DNA methylation at the 5 position of cytosine (5-mC) has emerged as a key epigenetic marker that plays essential roles in various biological and pathological processes. 5-mC can be converted to 5-hydroxymethylcytosine (5-hmC) by the ten–eleven translocation (TET) family proteins, which is now widely recognized as the “sixth base” in the mammalian genome, following 5-mC, the “fifth base”. 5-hmC is detected to be abundant in brain and embryonic stem cells, and is also distributed in many different human tissues. Emerging evidence has shown that 5-hmC and TET family might serve unique biological roles in many biological processes such as gene control mechanisms, DNA methylation regulation, and involved in many diseases, especially cancers. In this paper we provide an overview of the role of 5-hmC as a new sight of epigenetics in human cancer.
5-hmC; TET; epigenetics; DNA methylation; cancer
Acute lymphoblastic leukemia (ALL) is a malignant disorder of lymphoid progenitor cells that are committed to the B- or the T-cell lineage. The pathogenesis of ALL is heterogeneous and may be at least in part caused by genetic alterations. Although the modern sequencing technologies make it possible to rapidly discover novel genetic and epigenetic alterations and molecular targets for therapeutic intervention for ALL, conventional chemotherapy is still the most important therapeutic approach. Relapses and high morbidity and mortality remain major challenges particularly in adult patients with ALL. Therefore, development of novel chemotherapeutic agents remains in demand for ALL patients. In the course of seeking novel agents against ALL, we screened a library of small molecules and identified that PQJS380, a S-(E)-4-([7S,10S]-4-ethyl-7-isopropyl-2,5,8,12-tetraoxo-9-oxa-3,6,13,18-tetraaza-bicycle[13,2,1] octadec-1-en-10-yl)but-3-enyl octanethioate, showed potent anti-leukemia activity. PQJS380 inhibited the proliferation with IC50 values of 14.25 nM and 5 nM in REH and NALM-6 cells, respectively. PQJS380 had 10-fold higher molar potency than the front-line ALL drugs Ara-C and VP-16. The median IC50 value for leukemia blast cells from 17 patients with ALL was 52 nM. PQJS380 induced G1-phase arrest in REH cells, and S-phase in NALM-6 cells, respectively. Treatment of PQJS380 led to apoptosis in ALL cell lines (REH and NALM-6) and primary ALL cells. Our data supported that PQJS380 may be a promising lead compound for ALL treatment even though the precise targets remain to be elucidated.
acute lymphoblastic leukemia; chemotherapeutic agent; lead compound; PQJS380; apoptosis
Protein phosphatase methylesterase 1 (PPME1) is a protein phosphatase 2A (PP2A)-specific methyl esterase that negatively regulates PP2A through demethylation at its carboxy terminal leucine 309 residue. Emerging evidence shows that the upregulation of PPME1 is associated with poor prognosis in glioblastoma patients. By performing an array comparative genomic hybridization analysis to detect copy number changes, we have been the first to identify PPME1 gene amplification in 3.8% (5/131) of Chinese gastric cancer (GC) samples and 3.1% (4/124) of Chinese lung cancer (LC) samples. This PPME1 gene amplification was confirmed by fluorescence in situ hybridization analysis and is correlated with elevated protein expression, as determined by immunohistochemistry analysis. To further investigate the role of PPME1 amplification in tumor growth, short-hairpin RNA-mediated gene silencing was employed. A knockdown of PPME1 expression resulted in a significant inhibition of cell proliferation and induction of cell apoptosis in PPME1-amplified human cancer cell lines SNU668 (GC) and Oka-C1 (LC), but not in nonamplified MKN1 (GC) and HCC95 (LC) cells. The PPME1 gene knockdown also led to a consistent decrease in PP2A demethylation at leucine 309, which was correlated with the downregulation of cellular Erk and AKT phosphorylation. Our data indicate that PPME1 could be an attractive therapeutic target for a subset of GCs and LCs.
gastric cancer; lung cancer; PPME1 amplification; PP2A; shRNA-knockdown
A major problem in cancer treatment is the development of resistance to chemotherapeutic agents, multidrug resistance (MDR), associated with increased activity of transmembrane drug transporter proteins which impair cytotoxic treatment by rapidly removing the drugs from the targeted cells. Previously, it has been shown that heparin treatment of cancer patients undergoing chemotherapy increases survival. In order to determine whether heparin is capable reducing MDR and increasing the potency of chemotherapeutic drugs, the cytoxicity of a number of agents toward four cancer cell lines (a human enriched breast cancer stem cell line, two human breast cancer cell lines, MCF-7 and MDA-MB-231, and a human lung cancer cell line A549) was tested in the presence or absence of heparin. Results demonstrated that heparin increased the cytotoxicity of a range of chemotherapeutic agents. This effect was associated with the ability of heparin to bind to several of the drug transport proteins of the ABC and non ABC transporter systems. Among the ABC system, heparin treatment caused significant inhibition of the ATPase activity of ABCG2 and ABCC1, and of the efflux function observed as enhanced intracellular accumulation of specific substrates. Doxorubicin cytoxicity, which was enhanced by heparin treatment of MCF-7 cells, was found to be under the control of one of the major non-ABC transporter proteins, lung resistance protein (LRP). LRP was also shown to be a heparin-binding protein. These findings indicate that heparin has a potential role in the clinic as a drug transporter modulator to reduce multidrug resistance in cancer patients.
drug transport proteins; heparin; multidrug resistance (MDR); breast cancer
The androgen receptor (AR) is central to the initiation and progression of prostate cancer, even after castration. Its transcriptional activity has previously been studied in cell lines. A group at the University of Cambridge recently outlined the AR transcriptional program in tissue samples, with an emphasis on castration-resistant tumors. AR binding sites, gene-expression changes (in xenografts), and potential transcription factor interactions were notably different from those observed in cultured cells. These discrepancies suggest a distinct signaling network for the AR in vivo and serve as a reminder that results from in vitro models should be checked against clinical realities.
androgen receptor; binding site; castration-resistant prostate cancer; transcription factor; transcriptional program
Tyrosine kinase inhibitors are de facto the more used targeted therapies for upfront treatment of metastatic renal cell carcinoma (mRCC). Among these, sunitinib and pazopanib have reported greater activity in term of progression-free survival and overall survival compared with interferon-α or placebo in two independent large phase III studies. Despite a large use in clinical practice these molecules had never been compared. The COMPARZ study recently published in the New England Journal of Medicine reports the results of a non-inferiority trial that comparing pazopanib to sunitinib as first line of therapy in mRCC patients. Here we report the activity and safety data of the study and we discuss several critical aspects related to the study design and possible confounding factors that may alter the results’ interpretation.
pazopanib; sunitinib; renal cancer; first line; toxicity; non-inferiority study; phase III trial
Sorafenib is an oral multikinase inhibitor targeting Raf and other kinases. The anti-tumor effect of sorafenib is thought to be mediated through its inhibition of the RAS–Raf–Erk pathway, as well as its inhibition of VEGFR and PDGFR. Sorafenib has been effective at treating patients with renal cell carcinoma (RCC). Ovarian clear cell carcinoma (OCCC) is a chemoresistant subtype of ovarian cancer. OCCC is represented by cells with clear cytoplasm that resemble those observed in RCC. Using a microarray database, the gene expression profile of OCCC was similar to that of RCC. The effects of sorafenib against human OCCC are unknown. Therefore, we used sorafenib to treat two patients with recurrent chemoresistant OCCC, and observed good effect in both of them without severe side effects. We believe that sorafenib is an effective agent against OCCC. Given the chemoresistant nature of this tumor, this drug appears to be very valuable.
sorafenib; ovarian clear cell carcinoma; progression-free survival
Chemokines produced in distinct tissue microenvironments sustain migration of mature lymphocytes in lymphoglandula. Chemokine receptors expressed on chronic lymphocytic leukemia (CLL) cells regulate the migration of the leukemia cells within the bone marrow (BM), lymphoid organs in collaboration with chemokines. Chemokines form a pro-survival circuitry by regulating leukocyte trafficking, maintaining extended lymphocyte survival. Therefore, chemokines in tumor cell–microenvironment interactions represent a target for treatment of CLL. AMD3100 disrupts the CLL/microenvironment interactions and influences CXCL12/CXCR4 survival signaling. Fostamatinib, ibrutinib, and GS-1101 as B-cell receptor (BCR)-related kinase inhibitors inhibit BCR- and chemokine-receptor-signal-regulated kinase and have a good clinical response in CLL. Lenalidomide, sorafenib, and dasatinib are other additional drugs associated with chemokine in microenvironment. Inhibiting signaling through chemokine and microenvironment associated signaling are emerging as innovative therapeutic targets in CLL. In this article, we reviewed the role of chemokines in CLL microenvironment and novel therapeutics targeting CLL microenvironment.
chronic leukemia lymphoma; microenvironment; chemokines; chemokines receptors; targeted therapy
Multidrug resistance (MDR) is an important cause of treatment failure in acute lymphoblastic leukemia (ALL). The ABC family of membrane transporters is proposed, albeit with controversy, to be involved in this process. The present study aims to investigate the mRNA expression profile of several genes of this family, including ABCA2, ABCA3, ABCB1/MDR1, MRP1/ABCC1, MRP3/ABCC3, ABCG2/BCRP, and the intracellular transporter MVP/LRP, in childhood ALL, and to evaluate their association with response to therapy. Some genes in the present research are being studied for the first time in Iran. Using quantitative real-time PCR, we evaluated 27 children with ALL at diagnosis and 15 children with normal bone marrow. The status of response to therapy was assessed one year after the onset of therapy through investigating the IgH/TCRγ gene rearrangements. Our findings indicate a considerable and direct relationship between mRNA expression levels of ABCA2, ABCA3, MDR1, and MRP1 genes and positive minimal residual disease (MRD) measured after one year of treatment. Statistical analysis revealed that expression of these genes higher than the cutoff point will raise the risk of MRD by 15-, 6.25-, 12-, and 9-fold, respectively. No relationship was found between of MVP/LRP, MRP3 and ABCG2 genes expression and ALL prognoses. Considering the direct and significant relationship between the increased expression of ABCA2, ABCA3, MDR1, and MRP1 genes and positive risk of MRD in children with ALL, evaluating the expression profile of these genes on diagnosis may identify high risk individuals and help plan a more efficient treatment strategy.
acute lymphoblastic leukemia; minimal residual disease; multidrug resistance; ABC transporter
The latent membrane protein 1 (LMP1), which is encoded by the Epstein–Barr virus (EBV), has been suggested to be one of the major oncogenic factors in nasopharyngeal carcinoma (NPC). In previous studies, we experimentally demonstrated that downregulation of LMP1 expression by targeting EBV-LMP1 DNAzyme (Dz1) could increase the radiosensitivity of NPC. However, how Dz1 contributes to the radiosensitivity in NPC is still not clear. In the present study, we confirmed that Dz1 decreases LMP1 expression and downregulates the expression of the catalytic subunit of telomerase (hTERT), both at the protein and mRNA levels (P < 0.01), and therefore, consequently inhibits telomerase activity (P < 0.05) in LMP1-positive NPC cells. We also observed that LMP1 mediated Akt phosphorylation is involved in the regulation of hTERT expression and phosphorylation. After LMP1 and hTERT expression was silenced by Dz1 and hTERT-targeted siRNA, respectively, the radiosensitivity increased in CNE1-LMP1 cells (P < 0.05). The inhibition was more significant after Dz1 treatment was combined with siRNA (P < 0.01). We concluded that hTERT expression and phosphorylation could be regulated by LMP1 through the Akt pathway, and Dz1 enhances radiosensitivity of LMP1-positive NPC cells by inhibiting telomerase activity.
DNAzyme; LMP1; hTERT; telomerase; Akt; radiosensitivity; NPC
Multidrug resistance (MDR) is a hallmark of cancer cells and a crucial factor in chemotherapy failure, cancer reappearance, and patient deterioration. We have previously described the physicochemical characteristics and the in vitro anticancer properties of a multifunctional doxorubicin-loaded liposomal formulation. Lipodox®, a commercially available PEGylated liposomal doxorubicin, was made multifunctional by surface-decorating with a cell-penetrating peptide, TATp, conjugated to PEG1000-PE, to enhance liposomal cell uptake. A pH-sensitive polymer, PEG2000-Hz-PE, with a pH-sensitive hydrazone (Hz) bond to shield the peptide in the body and expose it only at the acidic tumor cell surface, was used as well. In addition, an anti-nucleosome monoclonal antibody 2C5 attached to a long-chain polymer to target nucleosomes overexpressed on the tumor cell surface was also present. Here, we report the in vitro cell uptake and cytotoxicity of the modified multifunctional immunoliposomes as well as the in vivo studies on tumor xenografts developed subcutaneously in nude mice with MDR and drug-sensitive human ovarian cancer cells (SKOV-3). Our results show the ability of multifunctional immunoliposomes to overcome MDR by enhancing cytotoxicity in drug-resistant cells, compared with non-modified liposomes. Furthermore, in comparison with the non-modified liposomes, upon intravenous injection of these multifunctional immunoliposomes into mice with tumor xenografts, a significant reduction in tumor growth and enhanced therapeutic efficacy of the drug in both drug-resistant and drug-sensitive mice was obtained. The use of “smart” multifunctional delivery systems may provide the basis for an effective strategy to develop, improve, and overcome MDR cancers in the future.
multifunctional immunoliposomes; doxorubicin; doxil; Lipodox; multidrug resistance; 2C5 mAb; TAT peptide; pH-sensitive polymers; SKOV-3 cells
The efficacy of conventional radiation therapy for gastric cancer is controversial. In this study, we evaluated the in vitro and in vivo effects of continuous low-dose-rate irradiation by I-125 seeds on different histological types of gastric cancer cell lines. Three human gastric cancer cell lines (MKN74, MKN45, and NUGC4) were treated with or without continuous low-dose irradiation by I-125 seeds in vitro and in vivo. Cell viability, apoptosis, caspase-3 assay, and cell-cycle distribution were examined in vitro. Body weight and tumor volumes of BALB/c nude mice bearing MKN74, MKN45, and NUGC4 gastric cancer xenografts were measured, and in vivo cell proliferation and apoptosis assays were performed by Ki67 and TUNEL staining, respectively. Continuous low-dose-rate irradiation by I-125 seeds reduced cell viability and induced cell apoptosis through the activation of caspase-3, and led to the accumulation of cells in the G2/M phase in vitro. It also suppressed the growth of gastric cancer xenografts in nude mice, while inhibiting cell proliferation and inducing apoptosis as demonstrated by Ki67 and TUNEL staining. Therefore, our data suggest that continuous low-dose-rate irradiation by I-125 seeds could be a promising new option for gastric cancer treatment, regardless of histological origin.
I-125 seed irradiation; gastric cancer; apoptosis; cell cycle; caspase
Recent studies suggest that erythropoietin (EPO) has pleiotropic effects in several cell types in addition to hematopoietic cells; however, the role of EPO-mediated cell signaling in nonhematopoietic cells, including in cancer cells, remains controversial. Here, we report our findings of autocrine/paracrine production of EPO by breast cancer cells and its functional significance. We detected a significant level of autocrine/paracrine EPO in the conditioned medium from the culture of SKBR3 breast cancer cells, particularly when the cells were cultured in hypoxia. Through knockdown of EPO and EPO receptor expression and experimental elevation of EPO receptor expression in SKBR3 breast cancer cells, we demonstrated novel roles of autocrine/paracrine EPO-mediated cell signaling in regulating migration and invasion potential and stemness-like properties of breast cancer cells.
erythropoietin; autocrine/paracrine loop; migration and invasion; stemness; breast cancer
Increasing evidence suggests tumor-associated macrophages (TAMs) are polarized M2 subtype of macrophage that exerts pro-tumor effects and promote the malignancy of some cancers, but the concrete mechanism is not well defined. Our previous research exhibited that proto-oncogene AP-1 regulated IL-6 expression in macrophages and promoted the formation of M2 macrophages. In this study, we investigate whether extra-cellular stimulus M-CSF help this process or nuclear factor NFκB has a synergistic role in the activation state of polarized M2 subtype of macrophage. RAW 264.7 macrophage and 4T1 mouse breast cancer cells were co-cultured to reconstruct tumor microenvironment. Being co-cultured with 4T1 or its supernatant, the expression of c-Jun, the member of AP-1 family, has a dramatically increase both on the level of gene and on the protein in RAW 264.7 macrophages, but the expression of c-Fos does not increase neither on the level of gene nor on the protein. After co-cultured with 4T1, RAW 264.7 has a higher consumption of M-CSF than RAW 264.7 macrophages alone. With the stimulation of M-CSF, the mRNA of c-Jun increased significantly, but decreased remarkably after adding the anti-M-CSF. And at the same time, p50, the member of NFκB family, has a similar tendency to c-Jun. WB results suggest that with the stimulation of M-CSF, p-Jun in nuclear increases heavily but decreases after the neutralizing antibody added. Coimmunoprecipitation and immunoblotting techniques confirmed that c-Jun and p50 NFκB coprecipitated, and c-Jun protein expression is properly enhanced with rM-CSF effect. In conclusion, M-CSF induces macrophage transformation by upregulating c-Jun with a certain synergy of NFκB. Our study may present a novel therapeutic strategy against cancer.
M-CSF; NFκB; c-Jun; co-culture; transformation
Lymphoma patients treated with autologous transplantation (ASCT) live an increasingly long life with the recent advancement in therapeutic modalities. This has resulted in an increase in the incidence of therapy-related myeloid neoplasms (t-MN), which is one of the leading causes of non-relapse mortality. Several observational studies have linked the development of t-MN after ASCT with the intensity and frequency of chemotherapy, particularly alkylating agents, use of total body irradiation (TBI), and peripheral blood progenitor cells. In addition, role of genetic factors is increasingly being identified. It is postulated that the use of chemotherapy prior to ASCT results in DNA damage of progenitor cells, mitochondrial dysfunction, and altered gene expression related to DNA repair, metabolism as well as hematopoietic regulation. Cytogenetic studies have shown the presence of abnormalities in the peripheral blood progenitor cells prior to ASCT. It is, therefore, likely that the reinfusion of peripheral blood progenitor cells, proliferative stress on infused progenitor cells during hematopoietic regeneration and associated telomere shortening ultimately result in clonal hematopoiesis and blastic transformation. Cytopenias, myelodysplasia, or cytogenetic abnormalities are common and can be transient after ASCT; therefore, only when present together, they do confirm the diagnosis of t-MN. Attempts to reduce the occurrence of t-MN should be directed toward minimizing the exposure to the identified risk factors. Although the median survival is few months to less than a year, studies have shown the promising role of allogeneic transplantation in select young t-MN patients without high-risk cytogenetics. In this review we will explain the recent findings in the field of t-MN in lymphoma patients that have implications for identifying the molecular and genetic mechanisms of leukemogenesis and discuss potential strategies to reduce the risk of t-MN in this patient population.
therapy-related myeloid neoplasms; myelodysplasia; acute myeloid leukemia; autologous hematopoietic stem cell transplantation; Hodgkin lymphoma; non-Hodgkin lymphoma
Extremely high cancer incidence in Fanconi anemia (FA) patients has long suggested that the FA signaling pathway is a tumor suppressor pathway. Indeed, our recent findings, for the first time, indicate that the FA pathway plays a significant role in suppressing the development of non-FA human cancer. Also our studies on FA group D2 protein (FANCD2) have, among the first, documented the crosstalks between the FA and Rad6/Rad18 (HHR6) pathways upon DNA damage. In this review, we will discuss how our studies enhance the understanding of the FA tumor suppressor pathway.
the FA tumor suppressor pathway; Rad6/Rad18 pathway; DNA damage; DNA polymerase eta; translesion synthesis; non-FA human tumors
Few data are available outlining outcomes of panitumumab in advanced colorectal cancer patients benefiting from prior cetuximab-based regimens.
Patients and methods
Thirty patients with KRAS wild type metastatic colorectal cancer with clinical benefit from prior cetuximab-based regimens between May 2004 and October 2011 were reviewed at nine Italian Institutions. Inclusion key criteria included interruption of cetuximab for reasons other than progressive disease. Patients were classified according to prior regimens (0 or ≥1), prior response or stabilization, surgery of metastases, and Köhne prognostic score. At the time of subsequent progression, patients were treated with single agent panitumumab until progressive disease, unacceptable toxicity, or consent withdrawal.
Panitumumab obtained 67% disease control rate and 30% objective response rate, with median PFS of 4.2 and median OS of 9.6 mo. Patients with BRAF/NRAS/PI3KCA and KRAS (by mutant enriched technique) wild-type tumors had the best chance of response to panitumumab.
Single agent panitumumab provided significant clinical benefit in heavily pretreated patients without acquired resistance to prior cetuximab-based regimens.
colorectal cancer; cetuximab; panitumumab; rechallenge; KRAS
Early diagnosis and the ability to predict the most relevant treatment option for individuals is essential to improve clinical outcomes for non-small cell lung cancer (NSCLC) patients. Adenocarcinoma (ADC), a subtype of NSCLC, is the single biggest cancer killer and therefore an urgent need to identify minimally invasive biomarkers to enable early diagnosis. Recent studies, by ourselves and others, indicate that circulating miRNAs have potential as biomarkers. Here we applied global profiling approaches in serum from patients with ADC of the lung to explore if miRNAs have potential as diagnostic biomarkers. This study involved RNA isolation from 80 sera specimens including those from ADC patients (equal numbers of stages 1, 2, 3, and 4) and age- and gender-matched controls (n = 40 each). Six hundred and sixty-seven miRNAs were co-analyzed in these specimens using TaqMan low density arrays and qPCR validation using individual miRNAs. Overall, approximately 390 and 370 miRNAs were detected in ADC and control sera, respectively. A group of 6 miRNAs, miR-30c-1* (AUC = 0.74; P < 0.002), miR-616* (AUC = 0.71; P = 0.001), miR-146b-3p (AUC = 0.82; P < 0.0001), miR-566 (AUC = 0.80; P < 0.0001), miR-550 (AUC = 0.72; P = 0.0006), and miR-939 (AUC = 0.82; P < 0.0001) was found to be present at substantially higher levels in ADC compared with control sera. Conversely, miR-339-5p and miR-656 were detected at substantially lower levels in ADC sera (co-analysis resulting in AUC = 0.6; P = 0.02). Differences in miRNA profile identified support circulating miRNAs having potential as diagnostic biomarkers for ADC. More extensive studies of ADC and control serum specimens are warranted to independently validate the potential clinical relevance of these miRNAs as minimally invasive biomarkers for ADC.
micro-RNAs (miRNAs); circulating; minimally invasive; lung cancer; adenocarcinoma; biomarker; ROC curve
Mortality data by geographic area and trend-based surveillance are particularly relevant in orienting public health decisions targeting specific populations. We analyzed overall and site-specific cancer mortality between 1988 and 2009 in the metropolitan area of Naples and Caserta in southern Italy. Age-standardized mortality rates (SMR) were computed for each 5-y age group, by gender, primitive cancer site and specific Province in the overall population and age-defined subgroups. Cancer mortality trends were quantified by annual percent change (APC) and 95% confidence interval (CI). From Naples and Caserta, the reduction observed between 1988 and 2009 in SMR in males, but not in females, was significantly lower compared with the decrease reported at a national level (−11.4% and −28.4%, respectively). In elderly men, differences between local and national SMR were more pronounced (+13.6% compared with −2.7%). In males, the joinpoint regression analysis showed the following APC and 95% CI: −0.9%/year (−1.2; −0.7) and −0.6%/year (−1.0; −0.2) for Naples and Caserta, respectively. In females, estimates were −0.6%/year (−0.8; −0.5) and −0.7%/year (−1.2; −0.3). The overall orientation toward declining cancer mortality trends appeared in antithesis with the slight, but significant, increase for some tumors (e.g., pancreatic cancer in both genders). A complex mixture of heterogeneous factors concurs to explain the evidence observed including lifestyle, access to screening procedures, advancements in cancer diagnosis and treatment. Further details might eventually derive from biomonitoring studies for ascertaining the causal link between exposure to potential contaminants in air, water, and soil and cancer-related outcomes in the area of interest.
cancer mortality; time trends; Naples; metropolitan area; southern Italy; joinpoint; analysis
Chemotherapy has been widely used in cancer treatment, but the prognosis of the cancer patients following chemotherapy has not been substantially improved. Alternative strategies such as immunotherapy and their combinations with chemotherapy are now being considered; however, the effects of chemotherapy on the immune responses of cancer cells are not fully understood. In the present studies, we reveal a potential link between chemotherapy and cancer immunoresistance, we first examined the effects of chemopreventive agent DDP on the expression of a cell surface glycopreotein Trop-2 in lung cancer cells, and found that DDP not only induce Trop-2 surface expression in human lung cancer cells, but also induce T-cell apoptosis effectively. In order to investigate the relationship between DDP-induced Trop-2 expression and T-cell apoptosis, we stably transfected A549 and PC14 lung cancer cells with Trop-2 shRNA, the DDP-induced Trop-2 surface expression was effectively decreased in stably transfected cell lines, but chemotherapeutic reagent-induced cell proliferation inhibition and apoptosis were increased through inhibition of the MAPK signaling pathway. In vivo animal experiments showed that Trop-2 knockdown tumors displayed a slower growth rate than the control xenografts. Importantly, DDP treatment exhibited a strong antitumor activity in the mice with Trop-2 knockdown tumors, but only a marginal effect in the control group. Taken together, our data show that DDP resistance in lung cancer cells could be induced through increased surface expression of Trop-2, which at least partially by interfering with MAPK pathway. These results provide novel insight into the function of Trop-2 and encourage the design and testing of approaches targeting this protein and its partners.
Trop-2; lung cancer; immunoresistance; MAPK; DDP
Nasopharyngeal carcinoma (NPC) is uncommon worldwide but often highly invasive in late stages. Due to its special location and lack of specific symptoms, NPC is hardly detected in regular medical examination at the beginning. Development of sensitive and specific biomarkers should help to save lives against this type of disease. In the present report, we investigated the value of plasma miRNAs for diagnosis and prognosis of NPC. Using candidate approach, we selected 21 miRNAs from literature to compare their expression levels in the plasma of NPC patients and controls. As a result, 5 miRNAs showed diagnostic potentials (P < 0.01). Among them, miR-16, -21, -24, and -155 had increased levels in NPC patients, whereas the level of miR-378 was decreased. There was a negative correlation between plasma miRNA expression and cancer progression, where miR-21 was statistically significant in T and N staging and miR-16 and 24 were significant in N staging only. Combination of miR-16, -21, -24, -155, and -378 gives 87.7% of sensitivity and 82.0% of specificity for NPC diagnosis. Without miR-16, combination of the rest 4 miRNAs gives the same sensitivity but a slightly reduced specificity. After treatment, all 5 miRNAs were somewhat back to normal levels in patients without cancer recurrence but the prognostic value was not statistically significant. In conclusion, plasma miRNA expression is a useful biomarker for NPC diagnosis but not for its prognosis. More importantly, it is simple, effective, and non-invasive. Combination of several plasma miRNAs can increase both NPC diagnostic sensitivity and specificity.
nasopharyngeal carcinoma; NPC; miRNA; plasma; biomarker; diagnosis; prognosis
Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising molecule for anti-cancer therapies. Unfortunately, cancer cells frequently acquire resistance to rhTRAIL. Various co-treatments have been proposed to overcome apoptosis resistance to TRAIL. Here we show that downregulation of the deISGylase USP18 sensitizes cancer cells to rhTRAIL, whereas, elevate levels of USP18 inhibit TRAIL-induced apoptosis, in a deISGylase-independent manner. USP18 influences TRAIL signaling through the control of the IFN autocrine loop. In fact, cells with downregulated USP18 expression augment the expression of cellular TRAIL. Downregulation of cellular TRAIL abrogates the synergism between TRAIL and USP18 siRNA and also limits cell death induced by rhTRAIL. By comparing the apoptotic responsiveness to TRAIL in a panel of cancer cell lines, we have discovered a correlation between TRAIL levels and the apoptotic susceptibility to rhTRAIL, In cells expressing high levels of TRAIL-R2 susceptibility to rhTRAIL correlates with TRAIL expression. In conclusion, we propose that cellular TRAIL is an additional factor that can influence the apoptotic response to rhTRAIL.
IFN-α; IFNAR; TRAIL; TRAIL-R2; USP18; autocrine loop
ETV1 (ETS variant 1) is a transcription factor from the ETS family and an oncogene in several types of human malignancies. Paradoxically, a predicted inactivating mutation in ETV1 was previously found in a clone of HT1080 cells with reduced activity of p53. We report that elevated expression of ETV1 makes p53-null tumor cells hypersensitive to restoration of said tumor suppressor. Furthermore, elevated levels of either wild-type ETV1 or its truncated derivative, dETV1, which mimics the product of an oncogenic rearrangement in certain tumors, results in increased expression of mRNA for p14ARF, a known activator of p53. Accordingly, expression of a luciferase reporter, which is driven by a putative ARF promoter, was elevated by concomitant expression of either ETV1 or dETV1. Our observations point to yet another example of a tumor suppressor gene being activated by a potentially oncogenic signal. A better understanding of the mechanisms that allow a cell to bypass such safeguards is needed in order to predict and prevent the development of an oncogene-tolerant state during cancer evolution.
oncogenic transformation; tumor suppression; p14ARF; p53; ETV1
Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States when combining both genders. Circulating tumor cells (CTCs) are a prognostic marker for stage IV CRC patients. We hypothesized that CTC quantity varies among stage IV CRC populations.
Blood (7.5 ml) was prospectively collected from 90 stage IV CRC patients. EpCAM+ CTCs were analyzed with the FDA-approved CellSearch® system. CRC tumors were immunohistochemically stained for EpCAM expression. Imaging and clinicopathological data were collected. Statistical analysis was performed using correlation analysis, Kruskal–Wallis, Fisher exact, and log-rank test.
CTCs were detectable in 36/90 (40%) patients. Diffuse CRC metastases were associated with the highest CTC prevalence (24/40 [60%]), in contrast to limited lung (2/19 [11%]) or liver (10/31 [32%]) metastases (P = 0.027). The overall mean CTC number was 2.0 (range 0–56.3). The mean CTC number in patients with diffuse metastases was significantly higher (3.7 [SEM ± 1.7, range 0–56.3]) than with limited lung metastases (0.1 [± 0.1; range 0–1]) or liver metastases (0.9 [± 0.3, range 0–7.0]) (P = 0.001). CRC tumors were consistently expressing EpCAM. CTC numbers did not correlate with serum CEA levels or other routine clinical parameters (P = N.S.). Patients with diffuse metastases had the poorest overall survival (P = 0.0042).
CRC patients with diffuse metastases have the highest number of CTCs, in contrast to limited metastases to the liver or lungs. Future studies should correlate CTCs with recurrence patterns in patients with resected CRC lung or liver metastases to investigate whether CTCs represent micrometastatic disease causing early relapses.
colorectal cancer; circulating tumor cells; metastasis