Molecular classification of cancers has been significantly improved patient outcomes through the implementation of treatment protocols tailored to the abnormalities present in each patient's cancer cells. Breast cancer represents the poster child with marked improvements in outcome occurring due to the implementation of targeted therapies for estrogen receptor or human epidermal growth factor receptor-2 positive breast cancers. Important subtypes with characteristic molecular features as potential therapeutic targets are likely to exist for all tumor lineages including hepatocellular carcinoma (HCC) but have yet to be discovered and validated as targets. Because each tumor accumulates hundreds or thousands of genomic and epigenetic alterations of critical genes, it is challenging to identify and validate candidate tumor aberrations as therapeutic targets or biomarkers that predict prognosis or response to therapy. Therefore, there is an urgent need to devise new experimental and analytical strategies to overcome this problem. Systems biology approaches integrating multiple data sets and technologies analyzing patient tissues holds great promise for the identification of novel therapeutic targets and linked predictive biomarkers allowing implementation of personalized medicine for HCC patients.
Oligonucleotide array sequence analysis; Gene expression profiling; Hepatocellular carcinoma; Genomics; Systems biology; Proteomics
Because alterations of expression patterns and genomic copy numbers of thousands of genes are fundamental properties of cancer cells, and the application of high-throughput microarray-based genomic technologies for the analysis of cancer inevitably generate many false-positive results, it is rarely possible to select a reasonable number of candidate genes for therapeutic targets and/or biomarkers for diagnosis and prognosis. Therefore, it will be necessary to devise new experimental and analytical strategies to overcome this problem. This review summarizes recent advances in gene expression profiling of hepatocellular carcinoma and discusses future strategies for analyzing large and complicated data sets from microarray studies and how to integrate these with diverse genomic data.
Transcription factors are direct effectors of altered signaling pathways in cancer and frequently determine clinical outcomes in cancer patients. To uncover new transcription factors that would determine clinical outcomes in breast cancer, we systematically analyzed gene expression data from breast cancer patients. Our results revealed that Forkhead box protein M1 (FOXM1) is the top-ranked survival-associated transcription factor in patients with triple-negative breast cancer. Surprisingly, silencing FOXM1 expression led breast cancer cells to become more sensitive to doxorubicin (Dox). We found that FOXM1-dependent resistance to Dox is mediated by regulating DNA repair genes. We further demonstrated that NFκB1 interacts with FOXM1 in the presence of Dox to protect breast cancer cells from DNA damage. Finally, silencing FOXM1 expression in breast cancer cells in a mouse xenograft model significantly sensitized the cells to Dox. Our systematic approaches identified an unexpected role of FOXM1 in Dox resistance by regulating DNA repair genes, and our findings provide mechanistic insights into how FOXM1 mediates resistance to Dox and evidence that FOXM1 may be a promising therapeutic target for sensitizing breast cancer cells to Dox.
Androgen-insensitive DU145 and PC3 human prostate cancer cells express high levels of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4, and treatment of cells with methyl 2-cyano-3,11-dioxo-18β-olean-1,12-dien-30-oate (CDODA-Me) inhibited cell growth and downregulated Sp1, Sp3 and Sp4 expression. CDODA-Me (15 mg/kg/d) was a potent inhibitor of tumor growth in a mouse xenograft model (PC3 cells) and also decreased expression of Sp transcription factors in tumors. CDODA-Me-mediated downregulation of Sp1, Sp3 and Sp4 was due to induction of the transcriptional repressor ZBTB4 which competitively binds and displaces Sp transcription factors from GC-rich sites in Sp1, Sp3, Sp4 and Sp-regulated gene promoters. ZBTB4 levels are relatively low in DU145 and PC3 cells due to suppression by microRNA (miR) paralogs that are members of the miR-17-92 (miR-20a/17-5p) and miR-106b-25 (miR-106b/93) clusters. Examination of publically available prostate cancer patient array data showed an inverse relationship between ZBTB4 and miRs-20a/17-5p/106b/93 expression, and increased ZBTB4 in prostate cancer patients was a prognostic factor for increased survival. CDODA-Me induces ZBTB4 in prostate cancer cells through disruption of miR-ZBTB4 interactions and this results in downregulation of pro-oncogenic Sp transcription factors and Sp-regulated genes.
ZBTB4; CDODA-Me; Sp; miR-17-92; miR-106b
The incidence of the esophagogastric junction cancer is growing rapidly. The purpose of this study is to clarify the outcome of the ratio between metastatic and examined lymph nodes in esophagogastric junction cancer patients with or without 7 examined lymph nodes.
A total of 3,481 patients who underwent operation are identified from the Surveillance, Epidemiology, and End Results database. Different lymph nodes resected groups are analyzed to test the lymph nodes ratio factor.
There are 2522 patients with 7 or more lymph nodes resected and 959 patients with less than 7 lymph nodes resected. Lymph nodes ratio and lymph node involvement are independent prognostic factors. But the lymph nodes ratio categories have a better prognostic value than the lymph node involvement categories. Compared with lymph node involvement categories, lymph nodes ratio categories represent patients with more homogeneous overall survival rate.
This study defines that the lymph nodes ratio is an independent prognostic factor for esophagogastric junction cancer. The lymph nodes ratio can prevent stage migration and may be a helpful system to predict the prognosis of esophagogastric junction cancer patients.
Most patients with non–small cell lung cancer (NSCLC) have responded poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We investigated the involvement of insulin-like growth factor 1 receptor (IGF-1R) signaling in primary resistance to EGFR TKIs and the molecular determinants of resistance to IGF-1R TKIs.
Phosphorylated IGF-1R/insulin receptor (pIGF-1R/IR) was immunohistochemically evaluated in a NSCLC tissue microarray. We analyzed the antitumor effects of an IGF-1R TKI (PQIP or OSI-906), either alone or in combination with a small-molecular inhibitor (PD98059 or U0126) or with siRNA targeting K-Ras or MAPK/extracellular signal-regulated kinase kinase (MEK), in vitro and in vivo in NSCLC cells with variable histologic features and EGFR or K-Ras mutations.
pIGF-1R/IR expression in NSCLC specimens was associated with a history of tobacco smoking, squamous cell carcinoma histology, mutant (mut) K-Ras, and wild-type (wt) EGFR, all of which have been strongly associated with poor response to EGFR TKIs. IGF-1R TKIs exhibited significant antitumor activity in NSCLC cells with wt EGFR and wt K-Ras but not in those with mutations in these genes. Introduction of mut K-Ras attenuated the effects of IGF-1R TKIs on NSCLC cells expressing wt K-Ras. Conversely, inactivation of MEK restored sensitivity to IGF-TKIs in cells carrying mut K-Ras.
The mutation status of both EGFR and K-Ras could be predictive markers of response to IGF-1R TKIs. Also, MEK antagonism can abrogate primary resistance of NSCLC cells to IGF-1R TKIs.
EGFR; K-Ras; IGF-1R; lung cancer; TKI
In precancerous and cancerous lesions, excessive growth signals resulting from activation of oncogenes or loss of tumor suppressor genes lead to intensive replication stress, which is recognized by a high level of replication-associated DNA double-strand breaks (DSBs). However, the molecular mechanism by which cells alleviate excessive replication stress remains unclear. In this study, we report that the human nuclease/helicase DNA2 facilitates homologous recombination to repair replication-associated DNA double-strand breaks (DSBs), thereby providing cells with survival advantages under conditions of replication stress. The nuclease activity of DNA2 was required for DSB end resection, which allowed subsequent recruitment of RPA and RAD51 to repair DSBs and restart replication. More importantly, DNA2 expression was significantly increased in human cancers and its expression correlated with patient outcome. Our findings therefore indicate that enhanced activity of DSB resection likely constitutes one mechanism whereby precancerous and cancerous cells might alleviate replication stress.
DNA2; DNA end resection; homologous recombination; DNA repair; replication stress
There are 516 known kinases in the human genome. Because of their important role maintaining proper cellular function, they are often misregulated during tumorigenesis and associated with clinical outcomes in cancer patients, including clear cell renal cell carcinoma (ccRCC). However, less is known about the global expression status of these genes in renal cell carcinoma and their association with clinical outcomes. We performed a systematic analysis of gene expression for 503 kinases in 93 tumor samples and adjacent normal tissues. Expression patterns for 41 kinases were able to clearly differentiate tumor and normal samples. Expression of I-kappa-B kinase epsilon (IKBKE) was associated with a 5.3-fold increased risk of dying [95% confidence interval (CI): 1.93–14.59, P-value: 0.0012]. Individuals with high IKBKE expression were at a significantly increased risk of death (hazard ratio: 3.34, 95% CI: 1.07–10.40, P-value: 0.038) resulting in a significantly reduced overall survival time compared with those with low IKBKE tumor expression (P-value: 0.049). These results for IKBKE were validated in a replication population consisting of 237 ccRCC patients (P-value: 0.0021). Furthermore, IKBKE was observed to be higher expressed in tumors compared with adjacent normal tissues (P-value < 10−7). IKBKE is a member of the nuclear factor-kappaB (NF-κB) signaling pathway and interestingly, gene expression patterns for other members of the NF-κB pathway were not associated with survival, suggesting that IKBKE gene expression may be an independent marker of variation in overall survival. Overall, these results support a novel role for IKBKE expression in modulating overall survival in ccRCC patients.
Hepatocellular carcinoma (HCC) has the most rapidly rising cancer incidence in the US and Europe. The KLF6 tumor suppressor is frequently inactivated in HCC by loss-of-heterozygosity (LOH) and/or mutation.
Here we have analyzed 33 HBV- and 40 HCV-related HCCs for mRNA expression of wildtype KLF6 (wtKLF6) as well as the KLF6 variant 1 (SV1), a truncated, growth-promoting variant that antagonizes wtKLF6 function. The HCV-related tumors analyzed represented the full histologic spectrum from cirrhosis and dysplasia to metastatic cancer.
Expression of KLF6 mRNA is decreased in 73% of HBV-associated HCCs compared to matched surrounding tissue (ST), with reductions of ~80% in one-third of the patients. KLF6 mRNA expression is also reduced in dysplastic nodules from patients with HCV compared to cirrhotic livers (p < 0.005), with an additional, marked decrease in the very advanced, metastatic stage (p < 0.05). An increased ratio of KLF6SV1/wt KLF6 is present in a subset (6/33, 18%) of the HBV-related HCCs compared to matched ST. Reconstituting KLF6 in HepG2 cells by retroviral infection decreased proliferation and related markers including cyclin D1 and beta-catenin, increased cellular differentiation based on induction of albumin, E-cadherin, and decreased alpha fetoprotein.
We conclude that reduced KLF6 expression is common in both HBV- and HCV-related HCCs and occurs at critical stages during cancer progression. Effects of KLF6 are attributable to regulation of genes controlling hepatocyte growth and differentiation.
Hepatocellular carcinoma; Alternative splicing; KLF6SV1; Dysplasia; E-cadherin
Tumor cell proliferation requires both growth signals and sufficient cellular bioenergetics.The AMP-activated kinase (AMPK) pathway appears dominant over the oncogenic signaling pathway suppressing cell proliferation. This study investigated the preclinical efficacy of targeting the tumor bioenergetic pathway using a glycolysis inhibitor 2-deoxy glucose (2DG) and AMPK agonists, AICAR and metformin. We evaluated the in vitro anti-tumor activity of 2DG, metformin or AICAR alone, and 2DG in combination either with metformin or AICAR. We examined in vivo efficacy using xenograft mouse models. 2DG alone was not sufficient to promote tumor cell death, reflecting the limited efficacy demonstrated in clinical trials. A combined use of 2DG and AICAR also failed to induce cell death. However, 2DG and metformin led to significant cell death associated with decrease in cellular ATP, prolonged activation of AMPK, and sustained autophagy. Gene expression analysis and functional assays revealed that the selective AMPK agonist AICAR augments mitochondrial energy transduction (OXPHOS) while metformin compromises OXPHOS. Importantly, forced energy restoration with methylpyruvate reversed the cell death induced by 2DG and metformin, suggesting a critical role of energetic deprivation in the underlying mechanism of cell death. The combination of 2DG and metformin inhibited tumor growth in mouse xenograft models. Deprivation of tumor bioenergetics by dual inhibition of energy pathways might be an effective novel therapeutic approach for a broad spectrum of human tumors.
Tumor bioenergetics; Targeted therapy; Cancer energy metabolic pathway
Prostaglandin E2 (PGE2), the most abundant COX-2–derived prostaglandin found in colorectal cancer, promotes tumor cell proliferation and survival via multiple signaling pathways. However, the role of PGE2 in tumor hypoxia is not well understood. Here, we show a synergistic effect of PGE2 and hypoxia on enhancing ANGPTL4 expression and that elevation of ANGPTL4 promotes colorectal cancer growth. PGE2 induces ANGPTL4 expression at both the mRNA and protein levels under hypoxic conditions. Moreover, hypoxia induces one of the PGE2 receptors, namely EP1. Activation of EP1 enhances ANGPTL4 expression, whereas blockage of EP1 by its antagonist inhibits PGE2 induction of ANGPTL4 under hypoxic conditions. Importantly, over-expression of ANGPTL4 promotes cell proliferation and tumor growth in vitro and in vivo. In addition, treatment with ANGPTL4 recombinant protein increases colorectal carcinoma cell proliferation through effects on STAT1 signaling. The MAPK and Src pathways mediate ANGPTL4-induced STAT1 expression and activation. These results are relevant to human disease since we found that the expression of ANGPTL4 and STAT1 are elevated in 50% of human colorectal cancers tested and there is a positive correlation between COX-2 and ANGPTL4 as well STAT1 expression in colorectal carcinomas. Collectively, these findings suggest that PGE2 plays an important role in promoting cancer cell proliferation via ANGPTL4 under hypoxic conditions.
PGE2; hypoxia; ANGPTL4; colorectal cancer; proliferation
We investigated the clinical and biological significance of p130cas, an important cell signaling molecule, in ovarian carcinoma.
Expression of p130cas in ovarian tumors, as assessed by immunohistochemistry, was associated with tumor characteristics and patient survival. The effects of p130cas gene silencing with small interfering RNAs incorporated into neutral nanoliposomes (siRNA-DOPC), alone and in combination with docetaxel, on in vivo tumor growth and on tumor cell proliferation (proliferating cell nuclear antigen) and apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling) were examined in mice bearing orthotopic taxane-sensitive (HeyA8 and SKOV3ip1) or taxane-resistant (HeyA8-MDR) ovarian tumors (n = 10 per group). To determine the specific mechanisms by which p130cas gene silencing abrogates tumor growth, we measured cell viability (MTT assay), apoptosis (fluorescence-activated cell sorting), autophagy (immunoblotting, fluorescence, and transmission electron microscopy), and cell signaling (immunoblotting) in vitro. All statistical tests were two-sided.
Of 91 ovarian cancer specimens, 70 (76%) had high p130cas expression; and 21 (24%) had low p130cas expression. High p130cas expression was associated with advanced tumor stage (P < .001) and higher residual disease (>1 cm) following primary cytoreduction surgery (P = .007) and inversely associated with overall survival and progression-free survival (median overall survival: high p130cas expression vs low expression, 2.14 vs 9.1 years, difference = 6.96 years, 95% confidence interval = 1.69 to 9.48 years, P < .001; median progression-free survival: high p130cas expression vs low expression, 1.04 vs 2.13 years, difference = 1.09 years, 95% confidence interval = 0.47 to 2.60 years, P = .01). In mice bearing orthotopically implanted HeyA8 or SKOV3ip1 ovarian tumors, treatment with p130cas siRNA-DOPC in combination with docetaxel chemotherapy resulted in the greatest reduction in tumor growth compared with control siRNA therapy (92%–95% reduction in tumor growth; P < .001 for all). Compared with control siRNA therapy, p130cas siRNA-DOPC reduced SKOV3ip1 cell proliferation (31% reduction, P < .001) and increased apoptosis (143% increase, P < .001) in vivo. Increased tumor cell apoptosis may have persisted despite pan-caspase inhibition by the induction of autophagy and related signaling pathways.
Increased p130cas expression is associated with poor clinical outcome in human ovarian carcinoma, and p130cas gene silencing decreases tumor growth through stimulation of apoptotic and autophagic cell death.
Despite continual efforts to develop prognostic and predictive models of colorectal cancer by using clinicopathological and genetic parameters, a clinical test that can discriminate between patients with good or poor outcome after treatment has not been established. Thus, the authors aim to uncover subtypes of colorectal cancer that have distinct biological characteristics associated with prognosis and identify potential biomarkers that best reflect the biological and clinical characteristics of subtypes.
Unsupervised hierarchical clustering analysis was applied to gene expression data from 177 patients with colorectal cancer to determine a prognostic gene expression signature. Validation of the signature was sought in two independent patient groups. The association between the signature and prognosis of patients was assessed by Kaplan–Meier plots, log-rank tests and the Cox model.
The authors identified a gene signature that was associated with overall survival and disease-free survival in 177 patients and validated in two independent cohorts of 213 patients. In multivariate analysis, the signature was an independent risk factor (HR 3.08; 95% CI 1.33 to 7.14; p=0.008 for overall survival). Subset analysis of patients with AJCC (American Joint Committee on Cancer) stage III cancer revealed that the signature can also identify the patients who have better outcome with adjuvant chemotherapy (CTX). Adjuvant chemotherapy significantly affected disease-free survival in patients in subtype B (3-year rate, 71.2% (CTX) vs 41.9% (no CTX); p=0.004). However, such benefit of adjuvant chemotherapy was not significant for patients in subtype A.
The gene signature is an independent predictor of response to chemotherapy and clinical outcome in patients with colorectal cancer.
Epithelial ovarian cancers (EOCs) often exhibit morphologic features of embryonic Müllerian duct–derived tissue lineages and colonize peritoneal surfaces that overlie connective and adipose tissues. However, the mechanisms that enable EOC cells to readily adapt to the peritoneal environment are poorly understood. In this study, we show that expression of HOXA9, a Müllerian-patterning gene, is strongly associated with poor outcomes in patients with EOC and in mouse xenograft models of EOC. Whereas HOXA9 promoted EOC growth in vivo, HOXA9 did not stimulate autonomous tumor cell growth in vitro. On the other hand, expression of HOXA9 in EOC cells induced normal peritoneal fibroblasts to express markers of cancer-associated fibroblasts (CAFs) and to stimulate growth of EOC and endothelial cells. Similarly, expression of HOXA9 in EOC cells induced normal adipose- and bone marrow–derived mesenchymal stem cells (MSCs) to acquire features of CAFs. These effects of HOXA9 were due in substantial part to its transcriptional activation of the gene encoding TGF-β2 that acted in a paracrine manner on peritoneal fibroblasts and MSCs to induce CXCL12, IL-6, and VEGF-A expression. These results indicate that HOXA9 expression in EOC cells promotes a microenvironment that is permissive for tumor growth.
The human POK family members are transcription factors with a POZ domain and zinc fingers that act primarily as transcriptional repressors. Several members of this family are involved in oncogenesis and this prompted us to assess whether expression levels of individual POK family members are associated with clinical outcomes in cancer. We have observed that ZBTB4 is downregulated in breast cancer patients, and that its expression is significantly correlated with relapse-free survival. Further integrative analysis of mRNA and microRNA (miR) expression data from the NCI-60 cell lines revealed an inverse correlation between ZBTB4 and oncogenic miRs derived from the miR-17-92 cluster and its paralogues. The experimental results using MDA-MB-231 and MCF-7 human breast cancer cells confirm that miRNAs derived from these clusters, containing miR-17-5p, miR-20a, miR-106a, miR-106b and miR-93, negatively regulate ZBTB4 expression. Overexpression of ZBTB4 or restoration of ZBTB4 by using an antagomir inhibit growth and invasion of breast cancer cells, and this effect is due, in part, to ZBTB4-dependent repression of the specificity protein 1 (Sp1), Sp3, and Sp4 genes, and subsequent downregulation of several Sp-dependent oncogenes, in part, through competition between ZBTB4 and Sp transcription factors for GC-rich promoter sequences. These results confirm that ZBTB4 functions as a novel tumor suppressor gene with prognostic significance for breast cancer survival, and the oncogenic miR-17-92/ZBTB4/Sp axis may be a potential therapeutic target.
ZBTB4; miR-17-92 cluster; breast cancer; prognostic; Sp transcription factors
LIN28B is a homolog of LIN28 which induces pluripotency when expressed in conjunction with OCT4, SOX2, and KLF4 in somatic fibroblasts. LIN28B represses biogenesis of let-7 microRNAs and is implicated in both development and tumorigenesis. Recently, we have determined that LIN28B overexpression occurs in colon tumors. We conducted a comprehensive analysis of Lin28b protein expression in human colon adenocarcinomas. We found that LIN28B overexpression correlates with reduced patient survival and increased probability of tumor recurrence. In order to elucidate tumorigenic functions of LIN28B, we constitutively expressed LIN28B in colon cancer cells and evaluated tumor formation in vivo. Tumors with constitutive Lin28b expression exhibit increased expression of colonic stem cell markers LGR5 and PROM1, mucinous differentiation, and metastasis. Together, our findings point to a function for LIN28B in promoting colon tumor pathogenesis, especially metastasis.
LIN28B; LIN28; let-7; colon cancer; differentiation; metastasis
P120ctn interacts with E-cadherin, but no formal proof that p120ctn functions as a bone fide tumor suppressor gene has emerged. We report herein that p120ctn loss leads to tumor development in mice. We have generated a conditional knockout model of p120ctn whereby mice develop pre-neoplastic and neoplastic lesions in the oral cavity, esophagus and squamous forestomach. Tumor derived cells secrete granulocyte macrophage colony stimulating factor (GM-CSF), macrophage colony stimulating factor (M-CSF), monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α (TNFα). The tumors contain significant desmoplasia and immune cell infiltration. Immature myeloid cells comprise a significant percentage of the immune cells present, and likely participate in fostering a favorable tumor microenvironment, including the activation of fibroblasts.
Human squamous cell cancers are the most common epithelially derived malignancies. One example is esophageal squamous cell carcinoma (ESCC), which is associated with a high mortality rate (1) that is related to a propensity for invasion and metastasis (2). Here we report that periostin, a highly expressed cell adhesion molecule, is a key component of a novel tumor invasive signature obtained from an organotypic culture model of engineered ESCC. This tumor invasive signature classifies with human ESCC microarrays, underscoring its utility in human cancer. Genetic modulation of periostin promotes tumor cell migration and invasion as revealed in gain of and loss of function experiments. Inhibition of EGFR signaling and restoration of wild-type p53 function were each found to attenuate periostin, suggesting interdependence of two common genetic alterations with periostin function. Collectively, our studies reveal periostin as an important mediator of ESCC tumor invasion and they indicate that organotypic (3D) culture can offer an important tool to discover novel biologic effectors in cancer.
tumor microenvironment; periostin; EGFR; p53
The heparin-degrading endosulfatases sulfatase 1 (SULF1) and sulfatase 2 (SULF2) have opposing effects in hepatocarcinogenesis despite structural similarity. Using mRNA expression arrays, we analyzed the correlations of SULF expression with signaling networks in human hepatocellular carcinomas (HCCs) and the associations of SULF expression with tumor phenotype and patient survival. Data from two mRNA microarray analyses of 139 and 36 HCCs and adjacent tissues were used as training and validation sets. Partek and Metacore software were used to identify SULF correlated genes and their associated signaling pathways. Associations between SULF expression, the hepatoblast subtype of HCC, and survival were examined. Both SULF1 and 2 had strong positive correlations with periostin, IQGAP1, TGFB1, and vimentin and inverse correlations with HNF4A and IQGAP2. Genes correlated with both SULFs were highly associated with the cell adhesion, cytoskeletal remodeling, blood coagulation, TGFB, and Wnt/β-catenin and epithelial mesenchymal transition signaling pathways. Genes uniquely correlated with SULF2 were more associated with neoplastic processes than genes uniquely correlated with SULF1. High SULF expression was associated with the hepatoblast subtype of HCC. There was a bimodal effect of SULF1 expression on prognosis, with patients in the lowest or highest tertile having a worse prognosis than those in the middle tertile. SULFs have complex effects on HCC signaling and patient survival. There are functionally similar associations with cell adhesion, ECM remodeling, TGFB, and WNT pathways, but also unique associations of SULF1 and SULF2. The roles and targeting of the SULFs in cancer require further investigation.
Cancer cells are metabolically stressed during tumour progression due to limited tumour vascularity and resultant nutrient, growth factor and oxygen deficiency that can induce cell death and inhibit tumour growth. We demonstrate that Rab25, a small GTPase involved in endosomal recycling, that is genomically amplified in multiple tumour lineages, is a key regulator of cellular bioenergetics and autophagy. RAB25 enhanced survival during nutrient stress by preventing apoptosis and autophagy via binding and activating AKT leading to increased glucose uptake and improved cellular bioenergetics. Unexpectedly, Rab25 induced the accumulation of glycogen in epithelial cancer cells, a process not previously identified. Strikingly, an increase in basal ATP levels combined with AKT-dependent increases in glucose uptake and glycogen storage allowed maintenance of ATP levels during bioenergetic stress. The clinical relevance of these findings was validated by the ability of a Rab25-dependent expression profile enriched for bioenergetics targets to identify patients with a poor prognosis. Thus, Rab25 is an unexpected regulator of cellular bioenergetics implicated as a useful biomarker and potential therapeutic target.
AKT; bioenergetic; cell death; glycogen; Rab25
ESR1 is one of the most important transcription factors and therapeutic targets in breast cancer. By applying systems-level re-analysis of publicly available gene expression data, we uncovered a potential regulator of ESR1. We demonstrated that orphan nuclear receptor NR2E3 regulates ESR1 via direct binding to the ESR1 promoter with concomitant recruitment of PIAS3 to the promoter in breast cancer cells, and is essential for physiological cellular activity of ESR1 in estrogen receptor (ER)-positive breast cancer cells. Moreover, expression of NR2E3 was significantly associated with recurrence-free survival and a favourable response to tamoxifen treatment in women with ER-positive breast cancer. Our results provide mechanistic insights on the regulation of ESR1 by NR2E3 and the clinical relevance of NR2E3 in breast cancer.
breast cancer; genomics; microarray; NR2E3; nuclear receptor
Metastasis-related recurrence often occurs in hepatocellular carcinoma (HCC) patients who receive curative therapies. At present, it is challenging to identify patients with high risk of recurrence, which would warrant additional therapies. In this study, we sought to analyze a recently developed metastasis-related gene signature for its utility in predicting HCC survival using two independent cohorts consisting of a total of 386 patients who received radical resection. Cohort-1 contained 247 predominantly HBV-positive cases analyzed with an Affymetrix platform, while cohort-2 contained 139 cases with mixed etiology analyzed with the NCI Oligo Set microarray platform. We employed a survival risk prediction algorithm with training, test, and independent cross-validation strategies and found that the gene signature is predictive of overall and disease-free survival. Importantly, risk was significantly predicted independently of clinical characteristics and microarray platform. In addition, survival prediction was successful in patients with early disease, such as small (<5 cm in diameter) and solitary tumors, and the signature predicted particularly well for early recurrence risk (<2 years), especially when combined with serum alpha fetoprotein or tumor staging. In conclusion, we have demonstrated in two independent cohorts with mixed etiologies and ethnicity that the metastasis gene signature is a useful tool to predict HCC outcome, suggesting the general utility of this classifier. We recommend the use of this classifier as a molecular diagnostic test to assess the risk that an HCC patient will develop tumor relaps within 2 years after surgical resection, particularly for those with early stage tumors and solitary presentation.
Early Recurrence; Prognosis; Gene Signature; HCC
Gene expression is suppressed by DNA methylation. The goal of this study was to identify genes whose CpG site methylation and mRNA expression are associated with recurrence after surgical resection for hepatocellular carcinoma (HCC). Sixty-two HCCs were examined by both whole genome DNA methylation and transcriptome analysis. The Cox model was used to select genes associated with recurrence. A validation was performed in an independent cohort of 66 HCC patients. Among fifty-nine common genes, increased CpG site methylation and decreased mRNA expression were associated with recurrence for 12 genes (Group A), whereas decreased CpG site methylation and increased mRNA expression were associated with recurrence for 25 genes (Group B). The remaining 22 genes were defined as Group C. Complement factor H (CFH) and myosin VIIA and Rab interacting protein (MYRIP) in Group A; proline/serine-rich coiled-coil 1 (PSRC1), meiotic recombination 11 homolog A (MRE11A), and myosin IE (MYO1E) in Group B; and autophagy-related protein LC3 A (MAP1LC3A), and NADH dehydrogenase 1 alpha subcomplex assembly factor 1 (NDUFAF1) in Group C were validated. In conclusion, potential tumor suppressor (CFH, MYRIP) and oncogenes (PSRC1, MRE11A, MYO1E) in HCC are reported. The regulation of individual genes by methylation in hepatocarcinogenesis needs to be validated.
Carcinoma, Hepatocellular; Gene Expression Profiling; Microarray analysis; DNA methylation; Survival
RNA interference holds tremendous potential as a therapeutic approach, especially in the treatment of malignant tumors. However, efficient and biocompatible delivery methods are needed for systemic delivery of small interfering RNA (siRNA). To maintain a high level of growth, tumor cells scavenge high-density lipoprotein (HDL) particles by overexpressing its receptor: scavenger receptor type B1 (SR-B1). In this study, we exploited this cellular characteristic to achieve efficient siRNA delivery and established a novel formulation of siRNA by incorporating it into reconstituted HDL (rHDL) nanoparticles. Here, we demonstrate that rHDL nanoparticles facilitate highly efficient systemic delivery of siRNA in vivo, mediated by the SR-B1. Moreover, in therapeutic proof-of-concept studies, these nanoparticles were effective in silencing the expression of two proteins that are key to cancer growth and metastasis (signal transducer and activator of transcription 3 and focal adhesion kinase) in orthotopic mouse models of ovarian and colorectal cancer. These data indicate that an rHDL nanoparticle is a novel and highly efficient siRNA carrier, and therefore, this novel technology could serve as the foundation for new cancer therapeutic approaches.
Angiogenesis is critical for tumor growth and metastasis, and several inhibitors of angiogenesis are currently in clinical use for the treatment of cancer. However, not all patients benefit from antiangiogenic therapy, and those tumors that initially respond to treatment ultimately become resistant. The mechanisms underlying this, and the relative contributions of tumor cells and stroma to resistance, are not completely understood. Here, using species-specific profiling of mouse xenograft models of human lung adenocarcinoma, we have shown that gene expression changes associated with acquired resistance to the VEGF inhibitor bevacizumab occurred predominantly in stromal and not tumor cells. In particular, components of the EGFR and FGFR pathways were upregulated in stroma, but not in tumor cells. Increased activated EGFR was detected on pericytes of xenografts that acquired resistance and on endothelium of tumors with relative primary resistance. Acquired resistance was associated with a pattern of pericyte-covered, normalized revascularization, whereas tortuous, uncovered vessels were observed in relative primary resistance. Importantly, dual targeting of the VEGF and EGFR pathways reduced pericyte coverage and increased progression-free survival. These findings demonstrated that alterations in tumor stromal pathways, including the EGFR and FGFR pathways, are associated with, and may contribute to, resistance to VEGF inhibitors and that targeting these pathways may improve therapeutic efficacy. Understanding stromal signaling may be critical for developing biomarkers for angiogenesis inhibitors and improving combination regimens.