Myxoid/round-cell liposarcoma (MRCL) is a specific histological subtype that accounts for 30–35% of liposarcomas and whose virulence depends on the quantity of round-cells within the tumor. MRCL is associated with specific chromosomal translocations resulting in the formation of CHOP/FUS and CHOP/EWS fusion proteins. A high sensitivity of MRCL to trabectedin was reported.
We report the case of a 63-year-old woman with a bulky and metastatic MRCL, treated with trabectedin 1.5 mg/m2 as a first-line treatment. She experienced a long-lasting clinical benefit. The patients received 14 cycles of trabectedin and achieved a durable partial response to the metastases and a stable disease of the primary tumor, which is a very favorable safety profile. Also noteworthy is that we have observed a calcification of the primary tumor and the metastasis. The response, which lasted 30 months, led to a symptomatic improvement, associated with an excellent general condition and an absence of pain.
To the best of our knowledge, this is the first report of a MRCL treated with trabectedin that resulted in a calcification of the primary tumor and the metastases, associated with an outstandingly long response. This case suggests that trabectedin may represent a feasible first-line therapeutic option for patients with MRCL, with meaningful clinical benefits and an acceptable safety profile.
Myxoid liposarcoma; Trabectedin; Tumor calcification
ET-743 (trabectedin; Yondelis) is approved in Europe for the treatment of soft tissue sarcomas. Emerging phase 1 and 2 clinical data have shown high response rates in myxoid liposarcoma in part owing to the inhibition of the FUS-CHOP transcription factor. In this report, we show that modulation of specific oncogenic transcription factors by ET-743 may extend to other tumor types. We demonstrate that, among a panel of pediatric sarcomas, Ewing sarcoma family of tumors (ESFTs) cell lines bearing the EWS-FLI1 transcription factor are the most sensitive to treatment with ET-743 compared with osteosarcoma, rhabdomyosarcoma, and synovial sarcoma. We show that ET-743 reverses a gene signature of induced downstream targets of EWS-FLI1 in two different ESFT cell lines (P = .001). In addition, ET-743 directly suppresses the promoter activity of a known EWS-FLI1 downstream target NR0B1 luciferase reporter construct without changing the activity of a constitutively active control in ESFT cells. Furthermore, the effect is specific to EWS-FLI1, as forced expression of EWS-FLI1 in a cell type that normally lacks this fusion protein, HT1080 cells, induces the same NR0B1 promoter, but this activation is completely blocked by ET-743 treatment. Finally, we used gene set enrichment analysis to confirm that other mechanisms of ET-743 are active in ESFT cells. These results suggest a particular role for ET-743 in the treatment of translocation-positive tumors. In addition, the modulation of EWS-FLI1 makes it a novel targeting agent for ESFT and suggests that further development of this compound for the treatment of ESFT is warranted.
Myxoid liposarcoma is a relatively common malignant soft tissue tumor, characterized by a (12;16) translocation resulting in a FUS-DDIT3 fusion gene playing a pivotal role in its tumorigenesis. Treatment options in patients with inoperable or metastatic myxoid liposarcoma are relatively poor though being developed and new hope is growing.
Using kinome profiling and subsequent pathway analysis in two cell lines and four primary cultures of myxoid liposarcomas, all of which demonstrated a FUS-DDIT3 fusion gene including one new fusion type, we aimed at identifying new molecular targets for systemic treatment. Protein phosphorylation by activated kinases was verified by Western Blot and cell viability was measured before and after treatment of the myxoid liposarcoma cells with kinase inhibitors. We found kinases associated with the atypical nuclear factor-kappaB and Src pathways to be the most active in myxoid liposarcoma. Inhibition of Src by the small molecule tyrosine kinase inhibitor dasatinib showed only a mild effect on cell viability of myxoid liposarcoma cells. In contrast, inhibition of the nuclear factor-kappaB pathway, which is regulated by the FUS-DDIT3 fusion product, in myxoid liposarcoma cells using casein kinase 2 inhibitor 4,5,6,7-tetrabromobenzotriazole (TBB) showed a significant decrease in cell viability, decreased phosphorylation of nuclear factor-kappaB pathway proteins, and caspase 3 mediated apoptosis. Combination of dasatinib and TBB showed an enhanced effect.
Kinases associated with activation of the atypical nuclear factor-kappaB and the Src pathways are the most active in myxoid liposarcoma in vitro and inhibition of nuclear factor-kappaB pathway activation by inhibiting casein kinase 2 using TBB, of which the effect is enhanced by Src inhibition using dasatinib, offers new potential therapeutic strategies for myxoid liposarcoma patients with advanced disease.
High-grade soft tissue sarcomas are a heterogeneous, complex group of aggressive malignant tumors showing mesenchymal differentiation. Recently, soft tissue sarcomas have increasingly been classified on the basis of underlying genetic alterations; however, the role of aberrant DNA methylation in these tumors is not well understood and, consequently, the usefulness of methylation-based classification is unclear.
We used the Infinium HumanMethylation27 platform to profile DNA methylation in 80 primary, untreated high-grade soft tissue sarcomas, representing eight relevant subtypes, two non-neoplastic fat samples and 14 representative sarcoma cell lines. The primary samples were partitioned into seven stable clusters. A classification algorithm identified 216 CpG sites, mapping to 246 genes, showing different degrees of DNA methylation between these seven groups. The differences between the clusters were best represented by a set of eight CpG sites located in the genes SPEG, NNAT, FBLN2, PYROXD2, ZNF217, COL14A1, DMRT2 and CDKN2A. By integrating DNA methylation and mRNA expression data, we identified 27 genes showing negative and three genes showing positive correlation. Compared with non-neoplastic fat, NNAT showed DNA hypomethylation and inverse gene expression in myxoid liposarcomas, and DNA hypermethylation and inverse gene expression in dedifferentiated and pleomorphic liposarcomas. Recovery of NNAT in a hypermethylated myxoid liposarcoma cell line decreased cell migration and viability.
Our analysis represents the first comprehensive integration of DNA methylation and transcriptional data in primary high-grade soft tissue sarcomas. We propose novel biomarkers and genes relevant for pathogenesis, including NNAT as a potential tumor suppressor in myxoid liposarcomas.
Soft tissue sarcoma accounts for less than 1% of all malignant neoplasms and is comprised of a very heterogeneous group of tumors with over 50 different subtypes. Due to its diversity and rarity, developing new therapeutics has been difficult, at best. The standard of care in the treatment of advanced and metastatic disease over the last 30 years has been doxorubicin and ifosfamide, either alone or in combination. There has been significant focus on developing new therapeutics to treat primary and metastatic disease. Trabectedin (ecteinascidin-743) is a tetrahydroiso-quinoline alkaloid which has been evaluated in the treatment of metastatic soft tissue sarcoma.
To review the current evidence for the therapeutic use of trabectedin in patients with soft tissue sarcoma.
Five phase I studies in patients with solid tumors, all of which include sarcoma patients, evaluating the dosing and toxicity of trabectedin were performed with efficacy being evaluated as a secondary endpoint. Additionally, there are four phase I trials evaluating trabectedin in combination with frontline therapeutic drugs in soft tissue sarcoma. Four phase II studies were performed in soft-tissue sarcoma patients with objective response rates ranging from 3.7% to 17.1%. Additionally, in two compassionate use trials, objective response rates between 14% and 51% were seen, the largest response resulting from a study specifically focusing on liposarcoma.
Place in therapy:
Trabectedin is a potential therapeutic option for the management of soft-tissue sarcoma. It appears to have specific activity in a select group of histologies, most notably myxoid/round cell liposarcoma. Although it would be helpful to study the use of trabectedin in a randomized, controlled fashion, the relative rarity of soft-tissue sarcoma, and heterogeneity of the histologic subtypes, makes phase III trials a difficult prospect.
soft tissue sarcoma; metastatic; trabectedin; ET-743; Yondelis®
Rhabdomyolysis is an uncommon side effect of trabectedin which is used for the second line therapy of metastatic sarcoma after anthracycline and ifosfamide failure. This side effect may be due to pharmacokinetic interactions caused by shared mechanisms of metabolism involving the cytochrome P450 (CYP) system in the liver. Here, for the first time in literature, we describe the unexpected onset of heavy toxicity, including rhabdomyolysis, after the fourth course of trabectedin in a patient with retroperitoneal liposarcoma who at the same time was taking an alternative herbal medicine suspected of triggering this adverse event.
This is the case of a 56 year old Caucasian man affected by a relapsed de-differentiated liposarcoma who, after the fourth cycle of second-line chemotherapy with trabectedin, complained of sudden weakness, difficulty walking and diffuse muscle pain necessitating complete bed rest. Upon admission to our ward the patient showed grade (G) 4 pancytopenia and a marked increase in liver lytic enzymes, serum levels of myoglobin, creatine phosphokinase (CPK) and lactate dehydrogenase. No cardiac or kidney function injuries were present. Based on these clinical and laboratory features, our conclusive diagnosis was of rhabdomyolysis induced by trabectedin.
The patient did not report any trauma or muscular overexertion and no co-morbidities were present. He had not received any drugs during treatment with trabectedin, but upon further questioning the patient informed us he had been taking a folk medicine preparation of chokeberry (Aronia melanocarpa) daily during the last course of trabectedin and in the 2 subsequent weeks.
One week after hospitalization and cessation of intake of chokeberry extract, CPK and other markers of myolysis slowly returned to standard range, and the patient noted a progressive recovery of muscle strength.
The patient was discharged on day 14 when a blood transfusion and parenteral hydration gradually lowered general toxicity. Progressive mobilization of the patient was obtained as well as a complete normalization of the laboratory findings.
The level of evidence of drug interaction leading to the adverse event observed in our patient was 2 (probable). Thus our case underlines the importance of understanding rare treatment-related toxicities such as trabectedin-induced rhabdomyolysis and the possible role of the drug-drug interactions in the pathogenesis of this rare side effect. Furthermore, this report draws attention to a potential problem of particular concern, that of nutritional supplements and complementary and alternative drug interactions. These are not widely recognized and can cause treatment failure.
Trabectedin related rhabdomyolysis; Liposarcomas; Drug-drug interactions; Chokeberry (Aronia melanocarpa)-drugs interaction
Trabectedin and thioglitazones have been documented to induce adipocytic maturation in myxoid liposarcoma; we have noted this in our experience as well. Intriguingly, we have also encountered this same phenomenon in myxoid liposarcomas exposed to various combinations of neoadjuvant doxorubicin and ifosfamide systemic chemotherapy with preoperative radiation, where the pathological effects have been less characterized. We examined the histological changes, including adipocytic maturation, associated with this treatment in patients with myxoid liposarcoma and evaluated for prognostic significance.
Twenty-two patients were identified with histologically confirmed myxoid liposarcomas (9 with variable hypercellular areas) who were treated with neoadjuvant doxorubicin (75-90 mg/m2/continous infusion over 72h every 3 week) and ifosfamide (2.5 g/m2 daily x 4 every 3 weeks) for 4-6 cycles. Twenty-one patients received pre-operative radiation including 5 with concurrent gemcitabine. Pre- and post-treatment MRI studies were compared for changes in tumor area, fat content and contrast uptake, with the latter two estimated as: none, <25%, 25-49% and >50%. Post-treatment specimens were evaluated for hyalinization, necrosis and adipocytic maturation. Clinical follow-up was obtained.
Median age was 45 (26-72) years with a median tumor size of 11 (2-18) cm. All occurred in the lower extremities except for one case in the neck. As is common in myxoid liposarcoma, all had extensive treatment changes (>90%) with extensive hyalinization (n = 16; >90%) or prominent adipocytic maturation (n = 6; >50%) including 2 cases composed almost entirely of mature-appearing adipose tissue. Variable necrosis was identified (5-30%). MRI revealed a decrease in tumor area in all but one tumor (median, 65%), an increase in fat content in 7 tumors (n = 2, >50%;n = 2, 25-50%;n = 3,<25%), and a decrease in contrast enhancement in most tumors (n = 5, >50%; n = 9, 25-49%; n = 7, <25%). Median follow-up was 57 (12-96) months with 17 alive with no disease/metastases, 3 alive with disease and 2 dead of disease. Six patients developed metastases with median interval of 26 (22-51) months post resection. Four of 6 tumors with increased adipocytic maturation >50% on histology had increased fat detected by MRI (>25%). All 6 are alive but 2 developed metastases. In the remaining patients, 4 developed metastases with 14 alive and 2 dead of disease.
Myxoid liposarcoma exposed to neoadjuvant doxorubicin and ifosfamide and pre-operative radiation can have prominent adipocytic maturation similar to trabectedin treatment. Myxoid liposarcomas exhibit extensive treatment changes with prominent hyalinization being the most common histological change. Despite this, patients develop metastases regardless of adipocytic maturation. While of unclear significance, no patient with fatty maturation died of disease.
Adipocytic maturation; Myxoid liposarcoma; Treatment
The present study describes a rare case of a mesenteric liposarcoma that resulted in a complete remission (CR) following treatment with trabectedin (Yondelis®). The patient presented with abdominal pain and fever. An abdominal mass was identified that corresponded to a mixed-type high-grade mesenteric liposarcoma with wide areas of necrosis, areas of dedifferentiation and features of a leiomyosarcoma. Three months after the removal of the first mass, the patient underwent a second laparotomy, followed by treatment with doxorubicin and ifosfamide. Subsequently, the patient was started on therapy with trabectedin and a CR was noted following only four cycles of therapy. The best responses that are reported in the literature for cases of liposarcoma treated with trabectedin are mostly for liposarcomas of the myxoid/round cell type and are mainly partial responses. In the present study, trabectedin was used for the treatment of a mesenteric liposarcoma of mixed morphological features and a CR was achieved.
mesenteric liposarcoma; complete remission; trabectedin; Yondelis®; dedifferentiation; leiomyosarcoma
Myxoid liposarcoma is a subtype of liposarcoma. This specific subtype can be identified based on its characteristic histological and cytogenetical features. The tumor has a fusion transcript of the CHOP and TLS genes, which is caused by t(12;16)(q13;p11). Most of the fusion transcripts that have been identified fall into three categories, specifically type I (exons 7-2), type II (exons 5-2), and type III (exons 8-2). A total of seven myxoid liposarcomas associated with the rare phenomenon of cartilaginous differentiation have been documented in the literature. Currently, only one of these cases has been cytogenetically analyzed, and the analysis indicated that it was a type II TLS-CHOP fusion transcript in both the typical myxoid liposarcoma and cartilaginous areas. This study presents a second report of myxoid liposarcoma with cartilaginous differentiation, and includes a cytogenetical analysis of both the myxoid and cartilaginous areas.
Liposarcoma, myxoid; Cartilaginous differentiation; Cartilage; Heterologous component; TLS/CHOP fusion transcript
ET-743 (trabectedin, Yondelis®) and PM00104 (Zalypsis®) are marine derived compounds that have antitumor activity. ET-743 and PM00104 exposure over sustained periods of treatment will result in the development of drug resistance, but the mechanisms which lead to resistance are not yet understood.
Human chondrosarcoma cell lines resistant to ET-743 (CS-1/ER) or PM00104 (CS-1/PR) were established in this study. The CS-1/ER and CS-1/PR exhibited cross resistance to cisplatin and methotrexate but not to doxorubicin. Human Affymetrix Gene Chip arrays were used to examine relative gene expression in these cell lines. We found that a large number of genes have altered expression levels in CS-1/ER and CS-1/PR when compared to the parental cell line. 595 CS-1/ER and 498 CS-1/PR genes were identified as overexpressing; 856 CS-1/ER and 874 CS-1/PR transcripts were identified as underexpressing. Three zinc finger protein (ZNF) genes were on the top 10 overexpressed genes list. These genes have not been previously associated with drug resistance in tumor cells. Differential expressions of ZNF93 and ZNF43 genes were confirmed in both CS-1/ER and CS-1/PR resistant cell lines by real-time RT-PCR. ZNF93 was overexpressed in two ET-743 resistant Ewing sarcoma cell lines as well as in a cisplatin resistant ovarian cancer cell line, but was not overexpressed in paclitaxel resistant cell lines. ZNF93 knockdown by siRNA in CS-1/ER and CS-1/PR caused increased sensitivity for ET-743, PM00104, and cisplatin. Furthermore, ZNF93 transfected CS-1 cells are relatively resistant to ET-743, PM00104 and cisplatin.
This study suggests that zinc finger proteins, and ZNF93 in particular, are involved in resistance to ET-743 and PM00104.
FUS-DDIT3 is a chimeric protein generated by the most common chromosomal translocation t(12;16)(q13;p11) linked to liposarcomas, which are characterized by the accumulation of early adipocytic precursors. Current studies indicate that FUS-DDIT3- liposarcoma develops from uncommitted progenitors. However, the precise mechanism whereby FUS-DDIT3 contributes to the differentiation arrest remains to be elucidated.
Here we have characterized the adipocyte regulatory protein network in liposarcomas of FUS-DITT3 transgenic mice and showed that PPARγ2 and C/EBPα expression was altered. Consistent with in vivo data, FUS-DDIT3 MEFs and human liposarcoma cell lines showed a similar downregulation of both PPARγ2 and C/EBPα expression. Complementation studies with PPARγ but not C/EBPα rescued the differentiation block in committed adipocytic precursors expressing FUS-DDIT3. Our results further show that FUS-DDIT3 interferes with the control of initiation of translation by upregulation of the eukaryotic translation initiation factors eIF2 and eIF4E both in FUS-DDIT3 mice and human liposarcomas cell lines, explaining the shift towards the truncated p30 isoform of C/EBPα in liposarcomas. Suppression of the FUS-DDIT3 transgene did rescue this adipocyte differentiation block. Moreover, eIF4E was also strongly upregulated in normal adipose tissue of FUS-DDIT3 transgenic mice, suggesting that overexpression of eIF4E may be a primary event in the initiation of liposarcomas. Reporter assays showed FUS-DDIT3 is involved in the upregulation of eIF4E in liposarcomas and that both domains of the fusion protein are required for affecting eIF4E expression.
Taken together, this study provides evidence of the molecular mechanisms involve in the disruption of normal adipocyte differentiation program in liposarcoma harbouring the chimeric gene FUS-DDIT3.
Trabectedin is a promising anticancer agent, but dose-limiting hepatotoxicity was observed during phase I/II clinical trials. Dexamethasone (DEX) has been shown to significantly reduce trabectedin-mediated hepatotoxicity. The current study was designed to assess the capability of sandwich-cultured primary rat hepatocytes (SCRH) to predict the hepato-protective effect of DEX against trabectedin-mediated cytotoxicity. The role of multidrug resistance-associated protein 2 (Mrp2; Abcc2) in trabectedin hepatic disposition also was examined. In SCRH from wild-type Wistar rats, cytotoxicity was observed after 24-hr continuous exposure to trabectedin. SCRH pretreated with additional DEX (1 µM) exhibited a 2–3-fold decrease in toxicity at 100 nM and 1000 nM trabectedin. Unexpectedly, toxicity in SCRH from Mrp2-deficient (TR−) compared to wild-type Wistar rats was markedly reduced. Depletion of glutathione from SCRH using buthionine sulfoximine (BSO) mitigated trabectedin toxicity associated with 100 nM and 1000 nM trabectedin. Western blot analysis demonstrated increased levels of CYP3A1/2 and Mrp2 in SCRH pretreated with DEX; interestingly, Mrp4 expression was increased in SCRH after BSO exposure. Trabectedin biliary recovery in isolated perfused livers from TR− rats was decreased by ~75% compared to wild-type livers. In conclusion, SCRH represent a useful in vitro model to predict the hepatotoxicity of trabectedin observed in vivo. The protection by DEX against trabectedin-mediated cytotoxicity may be attributed, in part, to enhanced Mrp2 biliary excretion and increased metabolism by CYP3A1/2. Decreased trabectedin toxicity in SCRH from TR− rats, and in SCRH pretreated with BSO, may be due to increased basolateral excretion of trabectedin by Mrp3 and/or Mrp4.
Trabectedin; Dexamethasone; Sandwich-cultured primary rat hepatocytes; Multidrug resistance-associated proteins
Translocated in liposarcoma-CCAAT/enhancer binding protein homologous protein (TLS–CHOP) (also known as FUS-DDIT3) chimeric oncoprotein is found in the majority of human myxoid liposarcoma (MLS), but its molecular function remains unclear.
We knockdowned TLS–CHOP expression in MLS-derived cell lines by a specific small interfering RNA, and analysed the gene expression profiles with microarray.
TLS-CHOP knockdown inhibited growth of MLS cells, and induced an anticancer cytokine, melanoma differentiation-associated gene 7 (MDA-7)/interleukin-24 (IL-24) expression. However, double knockdown of TLS–CHOP and MDA-7/IL-24 did not inhibit MLS cell growth.
Repression of MDA-7/IL-24 expression by TLS–CHOP is required for MLS tumour growth, and TLS–CHOP may become a promising therapeutic target for MLS treatment.
TLS–CHOP; FUS-DDIT3; myxoid liposarcoma; MDA-7/IL-24
Interest in marine natural products has allowed the discovery of new drugs and trabectedin (ET-743, Yondelis), derived from the marine tunicate Ecteinascidia turbinata, was approved for clinical use in 2007. It binds to the DNA minor groove leading to interferences with the intracellular transcription pathways and DNA-repair proteins. In vitro antitumor activity was demonstrated against various cancer cell lines and soft tissue sarcoma cell lines. In phase I studies tumor responses were observed also in osteosarcomas and different soft tissue sarcoma subtypes. The most common toxicities were myelosuppression and transient elevation of liver function tests, which could be reduced by dexamethasone premedication. The efficacy of trabectedin was established in three phase II studies where it was administered at 1.5 mg/m2 as a 24 h intravenous infusion repeated every three weeks, in previously treated patients. The objective response rate was 3.7%–8.3% and the tumor control rate (which included complete response, partial response and stable disease) was obtained in half of patients for a median overall survival reaching 12 months. In nonpretreated patients the overall response rate was 17%. Twenty-four percent of patients were without progression at six months. The median overall survival was almost 16 months with 72% surviving at one year. Predictive factors of response are being explored to identify patients who are most likely to respond to trabectedin. Combination with other agents are currently studied with promising results. In summary trabectedin is an active new chemotherapeutic agents that has demonstrated its role in the armamentarium of treatments for patients with sarcomas.
soft tissue sarcoma; trabectedin; chemotherapy; DNA-minor groove binder
Myxoid round cell liposarcoma (MRCLS) is a common liposarcoma subtype characterized by a translocation that results in the fusion protein TLS:CHOP as well as by mixed adipocytic histopathology. Both the etiology of MRCLS and the mechanism of action of TLS:CHOP remain poorly understood. It was previously shown that ET-743, an antitumor compound with an unclear mechanism of action, is highly effective in patients with MRCLS. To identify the cellular origin of MRCLS, we engineered a mouse model in which TLS:CHOP was expressed under the control of a mesodermally restricted promoter (Prx1) in a p53-depleted background. This model resembled MRCLS histologically as well as functionally in terms of its specific adipocytic differentiation–based response to ET-743. Specifically, endogenous mesenchymal stem cells (MSCs) expressing TLS:CHOP developed into MRCLS in vivo. Gene expression and microRNA analysis of these MSCs showed that they were committed to adipocytic differentiation, but unable to terminally differentiate. We also explored the method of action of ET-743. ET-743 downregulated TLS:CHOP expression, which correlated with CEBPα expression and adipocytic differentiation. Furthermore, PPARγ agonists enhanced the differentiation process initiated by ET-743. Our work highlights how clinical observations can lead to the generation of a mouse model that recapitulates human disease and may be used to develop rational treatment combinations, such as ET-743 plus PPARγ agonists, for the treatment of MRCLS.
Liposarcoma remains the most common mesenchymal cancer, with a mortality rate of 60% among patients with this disease. To address the present lack of therapeutic options, we embarked upon a study of microRNA (miRNA) expression alterations associated with liposarcomagenesis with the goal of exploiting differentially expressed miRNAs and the gene products they regulate as potential therapeutic targets. MicroRNA expression was profiled in samples of normal adipose tissue, well-differentiated liposarcoma, and dedifferentiated liposarcoma by both deep sequencing of small RNA libraries and hybridization-based Agilent microarrays. The expression profiles discriminated liposarcoma from normal adipose tissue and well-differentiated from dedifferentiated disease. We defined over 40 miRNAs that were dysregulated in dedifferentiated liposarcomas in both the sequencing and the microarray analysis. The upregulated miRNAs included two cancer-associated species (miR-21, miR-26a), and the downregulated miRNAs included two species that were highly abundant in adipose tissue (miR-143, miR-145). Restoring miR-143 expression in dedifferentiated liposarcoma cells inhibited proliferation, induced apoptosis, and decreased expression of BCL2, TOP2A, PRC1, and PLK1. The downregulation of PRC1 and its docking partner PLK1 suggests that miR-143 inhibits cytokinesis in these cells. In support of this idea, treatment with a PLK1 inhibitor potently induced G2/M growth arrest and apoptosis in liposarcoma cells. Taken together, our findings suggest that miR-143 re-expression vectors or selective agents directed at miR-143 or its targets may have therapeutic value in dedifferentiated liposarcoma.
Liposarcomas are aggressive mesenchymal cancers with poor outcomes that exhibit remarkable histologic diversity, with five recognized subtypes. Currently, the mainstay of therapy for liposarcoma is surgical excision since liposarcomas are often resistant to traditional chemotherapy. In light of the high mortality associated with liposarcoma and the lack of effective systemic therapy, we sought novel genomic alterations driving liposarcomagenesis that might serve as therapeutic targets. ZIC1, a critical transcription factor for neuronal development, is overexpressed in all five subtypes of liposarcoma compared with normal fat and in liposarcoma cell lines compared with adipose-derived stem cells (ASC). Here we show that ZIC1 contributes to the pathogenesis of liposarcoma. ZIC1 knockdown inhibits proliferation, reduces invasion, and induces apoptosis in dedifferentiated and myxoid/round cell liposarcoma cell lines, but not in either ASC or a lung cancer cell line with low ZIC1 expression. ZIC1 knockdown is associated with increased nuclear expression of p27 protein, and the down-regulation of pro-survival target genes: BCL2L13, JunD, Fam57A, and EIF3M. Our results demonstrate that ZIC1 expression is essential for liposarcomagenesis and that targeting ZIC1 or its downstream targets may lead
to novel therapy for liposarcoma.
Liposarcoma; oncogenesis; ZIC1
Osteosarcomas are the most common primary malignant tumors of bone and show multiple and complex genomic aberrations. miRNAs are non-coding RNAs capable of regulating gene expression at the post transcriptional level, and miRNAs and their target genes may represent novel therapeutic targets or biomarkers for osteosarcoma. In order to investigate the involvement of miRNAs in osteosarcoma development, global microarray analyses of a panel of 19 human osteosarcoma cell lines was performed.
We identified 177 miRNAs that were differentially expressed in osteosarcoma cell lines relative to normal bone. Among these, miR-126/miR-126*, miR-142-3p, miR-150, miR-223, miR-486-5p and members of the miR-1/miR-133a, miR-144/miR-451, miR-195/miR-497 and miR-206/miR-133b clusters were found to be downregulated in osteosarcoma cell lines. All miRNAs in the paralogous clusters miR-17-92, miR-106b-25 and miR-106a-92 were overexpressed. Furthermore, the upregulated miRNAs included miR-9/miR-9*, miR-21*, miR-31/miR-31*, miR-196a/miR-196b, miR-374a and members of the miR-29 and miR-130/301 families. The most interesting inversely correlated miRNA/mRNA pairs in osteosarcoma cell lines included miR-9/TGFBR2 and miR-29/p85α regulatory subunit of PI3K. PTEN mRNA correlated inversely with miR-92a and members of the miR-17 and miR-130/301 families. Expression profiles of selected miRNAs were confirmed in clinical samples. A set of miRNAs, miR-1, miR-18a, miR-18b, miR-19b, miR-31, miR-126, miR-142-3p, miR-133b, miR-144, miR-195, miR-223, miR-451 and miR-497 was identified with an intermediate expression level in osteosarcoma clinical samples compared to osteoblasts and bone, which may reflect the differentiation level of osteosarcoma relative to the undifferentiated osteoblast and fully differentiated normal bone. Significance: This study provides an integrated analysis of miRNA and mRNA in osteosarcoma, and gives new insight into the complex genetic mechanisms of osteosarcoma development and progression.
Myxoid and round-cell liposarcoma is a frequently encountered liposarcoma subtype. The mainstay of treatment remains surgical excision with or without chemoradiation. However, treatment options are limited in the setting of metastatic disease. Cancer-testis antigens are immunogenic antigens with the expression largely restricted to testicular germ cells and various malignancies, making them attractive targets for cancer immunotherapy. Gene expression studies have reported the expression of various cancer-testis antigens in liposarcoma, with mRNA expression of CTAG1B, CTAG2, MAGEA9, and PRAME described specifically in myxoid and round-cell liposarcoma. Herein, we further explore the expression of the cancer-testis antigens MAGEA1, ACRBP, PRAME, and SSX2 in myxoid and round-cell liposarcoma by immunohistochemistry in addition to determining mRNA levels of CTAG2 (LAGE-1), PRAME, and MAGEA3 by quantitative real-time PCR. Samples in formalin-fixed paraffin-embedded blocks (n=37) and frozen tissue (n=8) were obtained for immunohistochemistry and quantitative real-time PCR, respectively. Full sections were stained with antibodies to MAGEA1, ACRBP, PRAME, and SSX2 and staining was assessed for intensity (1–2+) and percent tumor positivity. The gene expression levels of CTAG2, PRAME, and MAGEA3 were measured by quantitative real-time PCR. In total, 37/37 (100%) of the samples showed predominantly strong, homogenous immunoreactivity for PRAME. There was a variable, focal expression of MAGEA1 (11%) and SSX2 (16%) and no expression of ACRBP. Quantitative real-time PCR demonstrated PRAME and CTAG2 transcripts in all eight samples: six tumors with high mRNA levels; two tumors with low mRNA levels. The gene expression of MAGEA3 was not detected in the majority of cases. In conclusion, myxoid and round-cell liposarcomas consistently express PRAME by immunohistochemistry as well as CTAG2 and PRAME by qualitative real-time PCR. This supports the use of cancer-testis antigen-targeted immunotherapy in the treatment of this malignancy.
cancer-testis antigens; immunotherapeutics; myxoid and round-cell liposarcoma
Paclitaxel (Taxol) resistance remains a major obstacle for the successful treatment of ovarian cancer. MicroRNAs (miRNAs) have oncogenic and tumor suppressor activity and are associated with poor prognosis phenotypes. miRNA screenings for this drug resistance are needed to estimate the prognosis of the disease and find better drug targets. miRNAs that were differentially expressed in Taxol-resistant ovarian cancer cells, compared with Taxol-sensitive cells, were screened by Illumina Human MicroRNA Expression BeadChips. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to identify target genes of selected miRNAs. Kaplan–Meier survival analysis was applied to identify dysregulated miRNAs in ovarian cancer patients using data from The Cancer Genome Atlas. A total of 82 miRNAs were identified in ovarian carcinoma cells compared to normal ovarian cells. miR-141, miR-106a, miR-200c, miR-96, and miR-378 were overexpressed, and miR-411, miR-432, miR-494, miR-409-3p, and miR-655 were underexpressed in ovarian cancer cells. Seventeen miRNAs were overexpressed in Taxol-resistant cells, including miR-663, miR-622, and HS_188. Underexpressed miRNAs in Taxol-sensitive cells included miR-497, miR-187, miR-195, and miR-107. We further showed miR-663 and miR-622 as significant prognosis markers of the chemo-resistant patient group. In particular, the downregulation of the two miRNAs was associated with better survival, perhaps increasing the sensitivity of cancer cells to Taxol. In the chemo-sensitive patient group, only miR-647 could be a prognosis marker. These miRNAs inhibit several interacting genes of p53 networks, especially in TUOS-3 and TUOS-4, and showed cell line-specific inhibition effects. Taken together, the data indicate that the three miRNAs are closely associated with Taxol resistance and potentially better prognosis factors. Our results suggest that these miRNAs were successfully and reliably identified and would be used in the development of miRNA therapies in treating ovarian cancer.
microRNA; ovarian cancer; Taxol resistance; Kaplan–Meier survival analysis
Gene regulation in cells exposed to ionizing radiation (IR) occurs at the transcriptional and post-transcriptional levels. Recent studies have suggested that micro-RNA (miRNA) play a significant role in post-transcriptional gene regulation in irradiated cells. miRNA are RNA molecules 18–24 nucleotides in length that are involved in negatively regulating the stability or translation of target messenger RNA. Previous studies from our laboratory have shown that the expression of various miRNA is altered in IR-treated cells. In the present study we monitored genome-wide expression changes of miRNA transcriptome by massively parallel sequencing of human cells irradiated with X-rays. The baseline expression of 402 miRNA indicated a wide range of modulation without exposure to IR. Differences in the expression of many miRNA were observed in a time-dependent fashion following radiation treatment. The Short Time-series Expression Miner (STEM) clustering tool was used to characterize 190 miRNA to six statistically significant temporal expression profiles. miR-19b and miR-93 were induced and miR-222, miR-92a, and miR-941 were repressed after radiation treatment. miR-142-3p, miR-142-5p, miR-107, miR-106b, miR-191, miR-21, miR-26a, miR-182, miR-16, miR-146a, miR-22 and miR-30e exhibited two peaks of induction: one at 8 h and the other at 24 h post-irradiation. miR-378, miR-let-7a, miR-let-7g, miR-let-7f, miR-103b, miR-486-3p, miR-423-5p, miR-4448, miR-3607-5p, miR-20b, miR-130b, miR-155, miR-181, miR-30d and miR-378c were induced only at the 8-h time-point. This catalogue of the inventory of miRNA that are modulated as a response to radiation exposure will be useful for explaining the mechanisms of gene regulation under conditions of stress.
micro-RNA; differential gene expression; next-generation sequencing; TK6 cells; radiation effects
MicroRNAs (miRNAs) are coordinators of cellular differentiation, including granulopoiesis. Although differential expression of many miRNAs is associated with the maturation of granulocytes, analysis of differentially expressed miRNAs and their cellular localization across all stages of granulopoiesis, starting from hemopoietic stems cells, is not well characterized.
We analyzed whole cell miRNA and mRNA expression during granulopoiesis using Taqman low-density and Affymetrix arrays respectively. We also performed nuclear and cytoplasmic fractionation followed by Taqman low-density array and/or quantitative PCR to identify nuclear-enriched miRNAs in hemopoietic stem/progenitor cells, promyelocytes, myelocytes, granulocytes and several hemopoietic cell lines. Anti-correlation between the expression of miRNA and target pairs was used to determine putative miRNA targets.
Analyses of our array data revealed distinct clusters of differentially expressed miRNAs that are specific to promyelocytes and granulocytes. While the roles of many of these miRNAs in granulopoiesis are not currently known, anti-correlation of the expression of miRNA/mRNA target pairs identified a suite of novel target genes. Clusters of miRNAs (including members of the let-7 and miR-17-92 families) are downregulated in hemopoietic stem/progenitor cells, potentially allowing the expression of target genes known to facilitate stem cell proliferation and homeostasis. Additionally, four miRNAs (miR-709, miR-706, miR-690 and miR-467a*) were found to be enriched in the nucleus of myeloid cells and multiple hemopoietic cell lines compared to other miRNAs, which are predominantly cytoplasmic-enriched. Both miR-709 and miR-706 are nuclear-enriched throughout granulopoiesis and have putative binding sites of extensive complementarity downstream of pri-miRNAs. Nuclear enrichment of miR-467a* is specific to hemopoietic stem/progenitors and promyelocytes. These miRNAs are also nuclear-enriched in other hemopoietic cell lines, where nuclear sequestering may fine-tune the expression of cytoplasmic mRNA targets.
Overall, we have demonstrated differentially expressed miRNAs that have not previously been associated with hemopoietic differentiation and provided further evidence of regulated nuclear-enrichment of miRNAs. Further studies into miRNA function in granulocyte development may shed light on fundamental aspects of regulatory RNA biology and the role of nuclear miRNAs.
miRNAs; mRNA targets; Nuclear; Granulopoiesis; Gene expression; Stem cell
Soft tissue sarcomas are heterogeneous tumors that are difficult to treat. Up to 50 percent of patients develop metastatic disease and require systemic chemotherapy. Ifosfamide and doxorubicin are the two most active agents.
A 33-year-old Caucasian woman presented to our facility with a metastatic myxoid liposarcoma. Our patient was initially treated with surgery and radiation therapy, but experienced three recurrences during a six-year period, the first and the last occurring while our patient was pregnant. The first recurrence, which occurred two years after diagnosis and was localized in the left cervical and right axillary region, was treated with surgery followed by chemotherapy. Molecular analysis of this tumor showed a t(12,16) + translocation resulting in a FUS-DDIT3 or EWSR1-DDIT3 fusion. Three years later our patient experienced a second recurrence in the left supraclavicular fossa, upper thoracic and anterior mediastinum, which was treated with surgery alone. Eight months later, during the second pregnancy, our patient experienced a third recurrence as a large cervical mass that was treated, upon pregnancy, with trabectedin (1.5mg/m2/24-hour continuous infusion) for a total of 12 cycles. At that time a computed tomography scan showed long-term partial response with excellent treatment tolerability.
This case report illustrates the potential therapeutic activity of trabectedin in patients with myxoid liposarcoma.
Liposarcomas are mesenchymal tumors containing variable numbers of lipoblasts or adipocytes. The most common entities, well differentiated/dedifferentiated liposarcoma (WDLS/DDLS) and myxoid/round cell liposarcoma (MLS/RCLS), are both characterized by genetic rearrangements that affect the expression of the transcription factor DDIT3. DDIT3 induces liposarcoma morphology when ectopically expressed in a human fibrosarcoma. The role of DDIT3 in lipomatous tumors is, however, unclear. We have analyzed the expression of DDIT3 in 37 cases of liposarcoma (WDLS/DDLS n = 10, MLS/RCLS n = 16, and pleomorphic liposarcomas (PLS) n = 11) and 11 cases of common benign lipomas. Major cell subpopulations of WDLS/DDLS and MLS/RCLS tumors were found to express DDIT3 or the derived fusion protein, whereas PLS cases showed only a few positive cells. The lipomas contained large subpopulations expressing DDIT3. No correlation between numbers of DDIT3 expressing cells and numbers of lipoblasts/adipocytes was found. In vitro adipogenic treatment of two DDIT3 expressing cell lines induced lipid accumulation in small subpopulations only. Our results suggest a dual, promoting and limiting, role for DDIT3 in the formation of lipoblasts and liposarcoma morphology.
Trabectedin has mostly been studied in metastatic leiomyosarcoma and liposarcomas. Only limited data are available in other sarcoma subtypes, heavily pretreated and elderly patients. We retrospectively analyzed 101 consecutive sarcoma patients treated with trabectedin at our center. We recorded progression-free survival (PFS), clinical benefit rate (CBR, defined as complete or partial response or stable disease for at least 6 weeks) and toxicity. Covariates were sarcoma subtype, age and pretreatment. On average, trabectedin was administered for 2nd relapse/progression (range 1st to 12th line). A median of 2 cycles and a dose of 1.5 mg/m2 (range 1–21 cycles; 1.3–1.5 mg/m2) was administered. The median PFS under treatment with trabectedin was 2.1 months in the overall population. Different clinical outcomes were observed with respect to sarcoma subtypes: in patients with L-sarcoma [defined as leiosarcoma and liposarcoma (n=25)] the CBR was 55%. Notably, long lasting remissions were even observed in 7th-line treatment. In contrast, the majority of patients with non-L-sarcomas quickly progressed (median PFS 1.6 months). Nevertheless, a CBR of 34% was achieved, including long-lasting disease stabilization in subtypes such as rhabdomyosarcoma. Patients treated with trabectedin at 1st or 2nd line (n=16) achieved an improved PFS (median 5.7 months, range) and a CBR of 59%. No differences in terms of toxicity or efficacy were observed between patients older than 65 years (n=23) and younger patients (n=78). In this non-trial setting, port-associated complications were more frequent (14%) with trabectedin compared to other continuous infusion protocols administered at our outpatient therapy center. The majority of patients with relapsing L-sarcomas and a substantial fraction of patients with non-L-sarcomas derive a clinically meaningful benefit from trabectedin. Outpatient treatment is well tolerated also in elderly and heavily pretreated patients. Port-associated complications were observed at an unusually high rate. This suggests a drug-specific local toxicity that merits further investigation.
sarcoma; trabectedin; port complication