Expression pattern of the class I homeobox genes in ovarian carcinoma

LINC00629, a HOXB4-downregulated long noncoding RNA, inhibits glycolysis and ovarian cancer progression by destabilizing c-Myc

Ovarian cancer (OC) cells typically reprogram their metabolism to promote rapid proliferation. However, the role of long noncoding RNAs (lncRNAs) in the metabolic reprogramming of ovarian cancer, especially in glucose metabolic reprogramming, remains largely unknown. LINC00629 has been reported in our previous study to promote osteosarcoma progression. Upregulated LINC00629 was found to enhance the growth-suppressive effect of apigenin on oral squamous cell carcinoma. However, the precise function of LINC00629 in ovarian cancer development remains poorly understood. In this study, we found that LINC00629 was significantly downregulated in OC tissues and that low LINC00629 expression was associated with poor survival. Inhibition of LINC00629 was required for increased glycolysis activity and cell proliferation in ovarian cancer. In vivo, overexpression of LINC00629 dramatically inhibited tumor growth and lung metastasis. Mechanistically, LINC00629 interacted with and destabilized c-Myc, leading to its ubiquitination and proteasome degradation, further resulting in increased expression of downstream glycolysis-related genes and glucose metabolic reprogramming in OC. Interestingly, HOXB4 bound to the LINC00629 promoter and inhibited its transcription, indicating that LINC00629 is a transcriptional target of HOXB4. Collectively, these findings establish a direct role for LINC00629 in suppressing glucose metabolism, and HOXB4/LINC00629/c-Myc might serve as a potential biomarker and an effective therapeutic strategy for OC cancer treatment.

Genome-wide association and functional interrogation identified a variant at 3p26.1 modulating ovarian cancer survival among Chinese women

Ovarian cancer survival varies considerably among patients, to which germline variation may also contribute in addition to mutational signatures. To identify genetic markers modulating ovarian cancer outcome, we performed a genome-wide association study in 2130 Chinese ovarian cancer patients and found a hitherto unrecognized locus at 3p26.1 to be associated with the overall survival (P_combined = 8.90 × 10⁻¹⁰). Subsequent statistical fine-mapping, functional annotation, and eQTL mapping prioritized a likely casual SNP rs9311399 in the non-coding regulatory region. Mechanistically, rs9311399 altered its enhancer activity through an allele-specific transcription factor binding and a long-range interaction with the promoter of a lncRNA BHLHE40-AS1. Deletion of the rs9311399-associated enhancer resulted in expression changes in several oncogenic signaling pathway genes and a decrease in tumor growth. Thus, we have identified a novel genetic locus that is associated with ovarian cancer survival possibly through a long-range gene regulation of oncogenic pathways.

HOXB4 inhibits the proliferation and tumorigenesis of cervical cancer cells by downregulating the activity of Wnt/β-catenin signaling pathway

Homeobox B4 (HOXB4), which belongs to the homeobox (HOX) family, possesses transcription factor activity and has a crucial role in stem cell self-renewal and tumorigenesis. However, its biological function and exact mechanism in cervical cancer remain unknown. Here, we found that HOXB4 was markedly downregulated in cervical cancer. We demonstrated that HOXB4 obviously suppressed cervical cancer cell proliferation and tumorigenic potential in nude mice. Additionally, HOXB4-induced cell cycle arrest at the transition from the G0/G1 phase to the S phase. Conversely, loss of HOXB4 promoted cervical cancer cell growth both in vitro and in vivo. Bioinformatics analyses and mechanistic studies revealed that HOXB4 inhibited the activity of the Wnt/β-catenin signaling pathway by direct transcriptional repression of β-catenin. Furthermore, β-catenin re-expression rescued HOXB4-induced cervical cancer cell defects. Taken together, these findings suggested that HOXB4 directly transcriptional repressed β-catenin and subsequently inactivated the Wnt/β-catenin signaling pathway, leading to significant inhibition of cervical cancer cell growth and tumor formation.

Bayesian Hyper-LASSO Classification for Feature Selection with Application to Endometrial Cancer RNA-seq Data

Feature selection is demanded in many modern scientific research problems that use high-dimensional data. A typical example is to identify gene signatures that are related to a certain disease from high-dimensional gene expression data. The expression of genes may have grouping structures, for example, a group of co-regulated genes that have similar biological functions tend to have similar expressions. Thus it is preferable to take the grouping structure into consideration to select features. In this paper, we propose a Bayesian Robit regression method with Hyper-LASSO priors (shortened by BayesHL) for feature selection in high dimensional genomic data with grouping structure. The main features of BayesHL include that it discards more aggressively unrelated features than LASSO, and it makes feature selection within groups automatically without a pre-specified grouping structure. We apply BayesHL in gene expression analysis to identify subsets of genes that contribute to the 5-year survival outcome of endometrial cancer (EC) patients. Results show that BayesHL outperforms alternative methods (including LASSO, group LASSO, supervised group LASSO, penalized logistic regression, random forest, neural network, XGBoost and knockoff) in terms of predictive power, sparsity and the ability to uncover grouping structure, and provides insight into the mechanisms of multiple genetic pathways leading to differentiated EC survival outcome.

HOX Genes in High Grade Ovarian Cancer

HOX genes are highly conserved members of the homeobox superfamily that have a crucial role in determining cellular identity. High grade ovarian cancer is the most lethal gynaecological malignancy. Our understanding of the role of HOX genes in the oncogenesis of ovarian cancer is evolving, and here we review their dysregulated expression patterns, their function in cell survival and invasion, their potential uses as biomarkers, and ways in which HOX genes are being targeted with new and existing drugs.

HOXA4/HOXB3 gene expression signature as a biomarker of recurrence in patients with high-grade serous ovarian cancer following primary cytoreductive surgery and first-line adjuvant chemotherapy

OBJECTIVES

Aberrant homeobox (HOX) gene expression is reported in high-grade serous ovarian carcinoma (HGSOC), however, its prognostic significance remains unclear.

METHODS

HOX genes associated with progression-free survival (PFS) in a discovery cohort of primary HGSOC samples with RNA sequencing data, and those previously reported to be associated with clinical outcomes, were selected for qPCR testing in an independent training cohort of primary HGSOC samples (n=71). A prognostic model for PFS was developed using univariate and multivariate Cox regression. Patients were stratified into risk groups that optimized the test statistic. The model was tested in an independent HGSOC cohort from The Cancer Genome Atlas (TCGA) (n=320). The effect of selected HOX genes on drug sensitivity and reactive oxygen species (ROS) accumulation was examined in vitro.

RESULTS

Of 23 HOX genes tested in the training cohort, HOXA4 (HR=1.20, 95% CI=1.07-1.34, P=0.002) and HOXB3 (HR=1.09, 95% CI=1.01-1.17, P=0.027) overexpression were significantly associated with shorter PFS in multivariate analysis. Based on the optimal cutoff of the HOXA4/HOXB3 risk score, median PFS was 16.9months (95% CI=14.6-21.2months) and not reached (>80months) for patients with high and low risk scores, respectively (HR=8.89, 95% CI=2.09-37.74, P<0.001). In TCGA, the HOXA4/HOXB3 risk score was significantly associated with disease-free survival (HR=1.44, 95% CI=1.00-2.09, P=0.048). HOXA4 or HOXB3 overexpression in ovarian cancer cells decreased sensitivity to cisplatin and attenuated the generation of cisplatin-induced ROS (P<0.05).

CONCLUSIONS

HOXA4/HOXB3 gene expression-based risk score may be useful for prognostic risk stratification and warrants prospective validation in HGSOC patients.

miR-10b Inhibits Apoptosis and Promotes Proliferation and Invasion of Endometrial Cancer Cells via Targeting HOXB3

MicroRNAs are small RNA that are tightly interrelated with the initiation, development, and metastasis of cancers. Studies have shown that miR-10b is increased in various cancers. However, the underlying mechanisms of miR-10b in the occurrence and metastasis of endometrial cancer are poorly understood. To investigate its roles and correlations with Homeobox box 3 (HOXB3) in endometrial cancer, cancer tissues and adjacent normal endometrium tissues from 20 patients with endometrial cancer were studied. miR-10b expression was significantly up-regulated (p < 0.01) in endometrial cancer tissue, whereas HOXB3 was lowly expressed. The silence of miR-10b resulted in significantly enhanced cell apoptosis, and remarkably reduced cell proliferation, migration, and invasion (p < 0.05). Moreover, the protein levels of HOXB3 were increased in KLE cells with silenced miR-10b, and dual-luciferase reporter assay suggested that miR-10b could directly target HOXB3. Furthermore, overexpression of HOXB3 promoted cell apoptosis but inhibited cell proliferation, migration, and invasion (p < 0.01). To conclude, miR-10b might control cell apoptosis, proliferation, migration, and invasion in endometrial cancer via regulation of HOXB3 expression.

HOXB7-S3 inhibits the proliferation and invasion of MCF-7 human breast cancer cells

Homeobox B7 (HOXB7) has been found to be overexpressed in numerous types of human cancer. However, the role of HOXB7 in breast cancer remains to be elucidated. The aim of the present study was to investigate the effects of HOXB7 on the proliferation and invasion of breast cancer cells. Initially, reverse transcription quantitative polymerase chain reaction and western blotting were respectively employed to detect the mRNA and protein expression levels of the HOXB7 gene in the MDA-MB-231 and MCF-7 human breast cancer cell lines. Subsequently, small interfering RNAs designed to interfere with the expression of HOXB7 were used to knockdown the expression of HOXB7 in the MCF-7 cell line, the effects of which on cell proliferation, the apoptotic rate and invasion capacity were measured using a Cell Counting kit-8 assay, flow cytometry and transwell chambers, respectively. The results demonstrated that HOXB7 mRNA and protein were all overexpressed in MDA-MB-231 and MCF-7 breast cancer cell lines. Furthermore, HOXB7-S3 effectively inhibited the proliferation and invasion of MCF-7 breast cancer cells. In conclusion, these results demonstrated that HOXB7 may be a potential therapeutic target in human breast cancer.

miR-337 regulates the proliferation and invasion in pancreatic ductal adenocarcinoma by targeting HOXB7

Background

miRNAs are involved in coordinating a variety of cellular processes by regulating their target genes. Aberrant expression of miRNAs is correlated with various cancers. Previous studies have shown that miR-337 is significantly down-regulated in pancreatic ductal adenocarcinoma (PDAC) and that its expression is negatively correlated to the expression of HOXB7. Both miR-337 and HOXB7 are associated with the prognosis of PDAC patients. The purpose of this study was to identify the molecular mechanisms by which miR-337 acts as a tumor suppressor in PDAC.

Methods

Synthetic miR-337 mimics were transfected into PANC-1 and As-PC-1 cells using Lipofectamine™ 2000. The expression of HOXB7 protein was analyzed by Western blot. Luciferase reporter plasmids were constructed to confirm that HOXB7 3′UTR was the target of miR-337. The effect of miR-337 on cell proliferation was evaluated by CCK8 assay and colony formation assay, and cell invasion was evaluated by wound healing assay and transwell assay.

Results

Western blot and luciferase activity assays identified HOXB7 as the target of miR-337. A CCK-8 assay showed the absorbance of cells transfected with miR-337 mimics to be less than that of control cells, and that the number of cell clones was significantly decreased by miR-337 expression. A wound healing assay showed the invasion rate of cells transfected with miR-337 mimics at 36 h to be markedly lower than in controls. The average number of cells penetrating the Matrigel was significantly lower than the controls.

Conclusion

These findings suggest that miR-337 targets HOXB7 and effects significant suppression of PDAC cell proliferation and invasion.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_171

Levels of HOXB7 and miR-337 in pancreatic ductal adenocarcinoma patients

Background

Many studies have revealed that homeobox-B7 (HOXB7) and miR-337 play important roles in different types of human cancers. However, the relationship of HOXB7 and miR-337 in PDAC with clinicopathological factors has not yet been examined and their biological roles remain to be explored.

Methods

Using quantitative real-time RT-PCR and immunohistochemical staining, the expression of HOXB7 mRNA, miR-337, and HOXB7 protein in 44 PDAC samples was detected. Survival curves were made using follow-up data. The relationship between clinical or pathological characteristics and the prognosis was analyzed.

Results

The expression levels of HOXB7 mRNA and HOXB7 protein were significantly elevated in PDAC samples than that in non-malignant adjacent tissues. There were obvious differences in HOXB7 mRNA and proteins between tumors of different diameters, differentiation, TNM stage, and lymph node status. The level of miR-337 was markedly lower in tumor samples than in non-malignant adjacent tissues. The expression of miR-337 was related to TNM stage and lymph node status. There were significant differences in survival curves between patients with tumors <4 cm in diameter and patients with tumors ≥4 cm, among groups of well, moderately, and poorly differentiated tumors, between groups with TNM stages I, II and III or IV, between groups with metastatic lymph nodes and non-metastatic lymph nodes, among groups of HOXB7 protein expression negative (or weak) and positive, between groups with low levels of miR-337 expression and with high levels of miR-337 expression. The levels of HOXB7 mRNA, HOXB7 protein, and miR-337 were found to be associated with longer survival.

Conclusion

The present study showed that HOXB7 was over-expressed and miR-337 was minimally expressed in PDAC tissues, and their levels were related to TNM stage and lymph node status. The levels of HOXB7 mRNA, HOXB7 protein, and miR-337 were associated with survival in PDAC patients. Results suggested that HOXB7 and miR-337 could be used as determinants of PDAC patient prognosis.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1509730773118658.

HOXB7 mRNA is overexpressed in pancreatic ductal adenocarcinomas and its knockdown induces cell cycle arrest and apoptosis

Background

Human homeobox genes encode nuclear proteins that act as transcription factors involved in the control of differentiation and proliferation. Currently, the role of these genes in development and tumor progression has been extensively studied. Recently, increased expression of HOXB7 homeobox gene (HOXB7) in pancreatic ductal adenocarcinomas (PDAC) was shown to correlate with an invasive phenotype, lymph node metastasis and worse survival outcomes, but no influence on cell proliferation or viability was detected. In the present study, the effects arising from the knockdown of HOXB7 in PDAC cell lines was investigated.

Methods

Real time quantitative PCR (qRT-PCR) (Taqman) was employed to assess HOXB7 mRNA expression in 29 PDAC, 6 metastatic tissues, 24 peritumoral tissues and two PDAC cell lines. siRNA was used to knockdown HOXB7 mRNA in the cell lines and its consequences on apoptosis rate and cell proliferation were measured by flow cytometry and MTT assay respectively.

Results

Overexpression of HOXB7 mRNA was observed in the tumoral tissues and in the cell lines MIA PaCa-2 and Capan-1. HOXB7 knockdown elicited (1) an increase in the expression of the pro-apoptotic proteins BAX and BAD in both cell lines; (2) a decrease in the expression of the anti-apoptotic protein BCL-2 and in cyclin D1 and an increase in the number of apoptotic cells in the MIA PaCa-2 cell line; (3) accumulation of cell in sub-G1 phase in both cell lines; (4) the modulation of several biological processes, especially in MIA PaCa-2, such as proteasomal ubiquitin-dependent catabolic process and cell cycle.

Conclusion

The present study confirms the overexpression of HOXB7 mRNA expression in PDAC and demonstrates that decreasing its protein level by siRNA could significantly increase apoptosis and modulate several biological processes. HOXB7 might be a promising target for future therapies.

Prognostic impact of the cancer stem cell-related marker NANOG in ovarian serous carcinoma

OBJECTIVE

The objective of this study was to evaluate the prognostic significance of NANOG expression in ovarian serous carcinoma.

METHODS

The expression of NANOG was evaluated in 6 ovarian carcinoma cell lines, paclitaxel-resistant SKOV3 cells, and SKOV3 spheroid cells with semiquantitative reverse transcription-polymerase chain reaction and Western blotting. NANOG expression was also measured immunohistochemically in a tissue microarray containing ovarian tissues from 74 patients with ovarian serous carcinoma and 24 with ovarian serous cystadenoma. Each sample was scored based on signal intensity and proportion, and a score greater than 4 was considered "positive."

RESULTS

NANOG mRNA expression was variable in different ovarian cancer cell lines. The mRNA level of NANOG was increased in the paclitaxel-resistant SKOV3 cells and SKOV3 spheroid cells compared with that in the SKOV3 cells. NANOG expression was positive in 21.6% of 74 ovarian serous carcinoma tissues, but none of the ovarian serous cystadenoma tissues were positive. Positive NANOG expression was associated with residual tumor size after surgery (P = 0.032). The overall survival of the patients with positive NANOG expression was poorer than that of the patients with negative NANOG expression (P = 0.020). In patients with stage I and II disease, positive NANOG expression was independently associated with shorter overall survival compared with negative NANOG expression (40 vs 120 months, respectively; P = 0.031).

CONCLUSIONS

Positive NANOG expression is associated with poor prognosis of ovarian serous carcinoma. NANOG has potential as a predictor of survival for patients with ovarian carcinomas and may be involved in the mechanism of chemoresistance.

The loss of Hoxa5 function causes estrous acyclicity and ovarian epithelial inclusion cysts

Hox genes encode transcription factors that play essential roles during embryo morphogenesis and organogenesis. Expression of several Hox members persists at the adult age, indicating a wide spectrum of action from embryonic to postnatal life. In the present study, we reported that in adult mice, the Hoxa5 gene shows a dynamic expression profile in the ovary that depends on the estrous cycle, the gestational status, and the age of the female, suggesting that Hoxa5 may have distinct physiological functions in the ovary. Consistent with a role for Hoxa5 in ovarian function, Hoxa5(-/-) nulliparous females exhibit precocious puberty and an early onset of estrous acyclicity. They show a prolonged estrous cycle with increased metestrus-diestrus length, a phenotype that worsens with age. Older mutant females also develop ovarian epithelial inclusion cysts reminiscent of human endosalpingiosis. Immunolabeling studies suggest that these cysts originate from the ovarian surface epithelium, a source of epithelial ovarian carcinomas. Staining of the Hoxa5(-/-) ovarian cysts by the ovarian cancer markers paired box gene 8 (PAX8) and Wilms' tumor 1 (WT1) further strengthens the notion that these cysts may constitute preneoplastic lesions. Moreover, the deregulation of the estrous cycle and the presence of ovarian epithelial cysts in Hoxa5(-/-) older females correlate with a reduced expression of specific epidermal growth factor receptor signaling components, namely Egfr, Areg, and Btc. Altogether, our data unveil that Hoxa5, a stroma-specific gene, plays a significant role in ovarian biology and may be involved in ovarian cancer predisposition.

Optimizing molecular-targeted therapies in ovarian cancer: the renewed surge of interest in ovarian cancer biomarkers and cell signaling pathways

The hallmarks of ovarian cancer encompass the development of resistance, disease recurrence and poor prognosis. Ovarian cancer cells express gene signatures which pose significant challenges for cancer drug development, therapeutics, prevention and management. Despite enhancements in contemporary tumor debulking surgery, tentative combination regimens and abdominal radiation which can achieve beneficial response rates, the majority of ovarian cancer patients not only experience adverse effects, but also eventually relapse. Therefore, additional therapeutic possibilities need to be explored to minimize adverse events and prolong progression-free and overall response rates in ovarian cancer patients. Currently, a revival in cancer drug discovery is devoted to identifying diagnostic and prognostic ovarian cancer biomarkers. However, the sensitivity and reliability of such biomarkers may be complicated by mutations in the BRCA1 or BRCA2 genes, diverse genetic risk factors, unidentified initiation and progression elements, molecular tumor heterogeneity and disease staging. There is thus a dire need to expand existing ovarian cancer therapies with broad-spectrum and individualized molecular targeted approaches. The aim of this review is to profile recent developments in our understanding of the interrelationships among selected ovarian tumor biomarkers, heterogeneous expression signatures and related molecular signal transduction pathways, and their translation into more efficacious targeted treatment rationales.

HOX genes in ovarian cancer

The HOX genes are a family of homeodomain-containing transcription factors that determine cellular identity during development. Here we review a number of recent studies showing that HOX genes are strongly expressed in ovarian cancer, and that in some cases the expression of specific HOX genes is sufficient to confer a particular identity and phenotype upon cancer cells. We also review the recent advances in elucidating the different functions of HOX genes in ovarian cancer. A literature search was performed using the search terms HOX genes (including specific HOX genes), ovarian cancer and oncogenesis. Articles were accessed through searches performed in ISI Web of Knowledge, PubMed and ScienceDirect. Taken together, these studies have shown that HOX genes play a role in the oncogenesis of ovarian cancer and function in the inhibition of apoptosis, DNA repair and enhanced cell motility. The function of HOX genes in ovarian cancer oncogenesis supports their potential role as prognostic and diagnostic markers, and as therapeutic targets in this disease.