HOXB13 is downregulated in colorectal cancer to confer TCF4-mediated transactivation

Differential Protein Expression Patterns of HOXA13 and HOXB13 Are Associated with Bladder Cancer Progression

Bladder cancer is a common urological cancer and has the highest recurrence rate of any cancer. The aim of our study was to profile and characterize the protein expression of homeobox A13 (HOXA13) and homeobox B13 (HOXB13) genes in Malaysian bladder cancer patients. The protein expression of HOXA13 and HOXB13 in formalin-fixed paraffin-embedded (FFPE) bladder cancer tissues was determined by immunohistochemistry (IHC) analysis. The association between HOXA13/HOXB13 protein expression and demographic/clinicopathological characteristics of the bladder cancer patients was determined by chi-square analysis. Approximately 63.6% of the bladder cancer tissues harbored high HOXA13 expression. High HOXA13 expression was significantly associated with non-muscle invasive bladder cancer, lower tumor grade, higher number of lymph node metastases, and recurrence risk. In contrast, low HOXB13 expression (including those with negative expression) was observed in 71.6% of the bladder cancer tissues analyzed. Low HOXB13 expression was significantly associated with muscle-invasive bladder cancer, higher tumor stage, tumor grade, and metastatic risk. Both HOXA13 and HOXB13 protein expression were found to be associated with bladder tumorigenesis. The putative oncogenic and tumor suppressive roles of HOXA13 and HOXB13, respectively, suggest their potential utility as biomarkers in bladder cancer.

Variants in HOXB13, G132E and F127C, Are Associated With Prostate Cancer Risk in Japanese Men

BACKGROUND/AIM

Several studies have reported on the relationship between HOXB13 variants and an increased prostate cancer (PC) risk. To our knowledge there are not many studies on HOXB13 mutations in Japanese patients with prostate cancer, and there many issues remain uninvestigated. We herein clarified the association between HOXB13 genetic variants and PC risk in a Japanese population.

PATIENTS AND METHODS

PC patients were diagnosed at the Gunma University Hospital and affiliated hospitals from 1994 to 2016. Sanger sequencing was performed on the coding regions of the HOXB13 gene in 152 familial PC (FPC) patients. Genotyping was performed on single nucleotide variants (SNVs) found in Sanger sequencing in 230 FPC patients from 152 pedigrees and 197 sporadic PC (SPC) patients and 144 controls. Allelic frequency and clinical data for each variant were studied in cases and controls.

RESULTS

G132E and F127C were identified in FPC patients. The frequencies of G132E and F127C were significantly higher compared to the control group (p=0.039). In three families, seven PC patients shared the G132E variant, within second-to-third-degree relatives. It was not possible to clarify to pathogenicity of each SNV alone.

CONCLUSION

We found two significant variants of the HOXB13 gene, G132E, F127C by analyzing and comparing gene samples from PC and non-PC patients. Furthermore, the HOXB13 G132E variant was found significantly increased in the FPC group.

Expression profile and prognostic significance of HOXB13 in rectal cancer

BACKGROUND

This study aimed to investigate the expression pattern and prognostic significance of HOXB13 in rectal cancer.

METHODS

HOXB13 expression in rectal cancer and normal adjacent tissues was detected by reverse transcriptase-polymerase chain reaction and immunohistochemistry, and its clinicopathological characteristics and prognosis were statistically tested. Furthermore, we evaluated the association between tumor immune infiltrating cells and HOXB13 using the tumor immune estimation resource (TIMER) database. The potential biological mechanism associated with HOXB13 overexpression was investigated by gene set enrichment analysis (GSEA).

RESULTS

The expression of HOXB13 messenger RNA and protein in human rectal cancer tissues were significantly higher than those in the normal adjacent tissues (P < 0.05). HOXB13 expression was significantly correlated with depth of invasion, lymphatic invasion, lymph node metastasis, distant metastasis, and pathological tumor node metastasis stage (P < 0.05). Kaplan-Meier survival curves confirmed that HOXB13 overexpression was correlated negatively with overall survival and disease-free survival in rectal cancer (P < 0.05). Also, multivariate Cox regression analysis demonstrated that HOXB13 expression, age, and lymphatic invasion were independent prognostic factors in rectal cancer (P < 0.05). Plus, the results from the TIMER database indicated that HOXB13 expression has a significant association with several immune cell infiltrates. Finally, the GSEA results indicated that HOXB13 participated in the various immune-associated processes, including natural killer cell-mediated cytotoxicity and the T-cell receptor signaling pathway.

CONCLUSION

Our study showed an essential role of HOXB13 in rectal cancer immunity and prognosis. Significantly, the overexpression of HOXB13 leads to the worse prognosis for patients with rectal cancer, which will contribute to understanding molecular mechanisms associated with tumor pathogenesis and prognosis in this disease.

Comprehensive Network Analysis of Dysregulated Genes Revealed MNX1‐AS1/ hsa‐miR‐4697‐3p/ HOXB13 Axis in OC Chemotherapy Response

Poor chemotherapy response is the main obstacle of ovarian cancer (OC) treatment. Platinum‐refractory and ‐resistant patients are associated with a worse outcome than platinum‐sensitive and partially sensitive patients, but the comprehensive similarities and differences among them are not yet clear. In this study, we analyzed the data of patients with different chemotherapy response in The Cancer Genome Atlas. We found a minority of altered genes were overlapped in refractory and resistant groups, as did the enriched pathways and Gene Ontology terms. We noticed that the neural signaling and drug metabolism enzymes were more significantly enriched and the protein–protein interaction supported these results. The transcription analysis highlighted PDX1 as the common and central transcription factor in both refractory and resistant groups. The competing endogenous RNA (ceRNA) network shared no common ceRNA pairs, indicating a major difference in noncoding RNA post‐transcriptional regulation. In the end, we validated the expression, regulation, binding, and effect on chemotherapy response for selected MNX1‐AS1/hsa‐miR‐4697‐3p/HOXB13 in OC cell lines. Our study offered a novel and comprehensive insight into chemotherapy response, and potential targets for improving chemotherapy response in OC.

HOX and PBX gene dysregulation as a therapeutic target in glioblastoma multiforme

BACKGROUND

Glioblastoma multiforme (GBM) is the most common high-grade malignant brain tumour in adults and arises from the glial cells in the brain. The prognosis of treated GBM remains very poor with 5-year survival rates of 5%, a figure which has not improved over the last few decades. Currently, there is a modest 14-month overall median survival in patients undergoing maximum safe resection plus adjuvant chemoradiotherapy. HOX gene dysregulation is now a widely recognised feature of many malignancies.

METHODS

In this study we have focused on HOX gene dysregulation in GBM as a potential therapeutic target in a disease with high unmet need.

RESULTS

We show significant dysregulation of these developmentally crucial genes and specifically that HOX genes A9, A10, C4 and D9 are strong candidates for biomarkers and treatment targets for GBM and GBM cancer stem cells. We evaluated a next generation therapeutic peptide, HTL-001, capable of targeting HOX gene over-expression in GBM by disrupting the interaction between HOX proteins and their co-factor, PBX. HTL-001 induced both caspase-dependent and -independent apoptosis in GBM cell lines.

CONCLUSION

In vivo biodistribution studies confirmed that the peptide was able to cross the blood brain barrier. Systemic delivery of HTL-001 resulted in improved control of subcutaneous murine and human xenograft tumours and improved survival in a murine orthotopic model.

Molecular implications of HOX genes targeting multiple signaling pathways in cancer

Homeobox (HOX) genes encode highly conserved homeotic transcription factors that play a crucial role in organogenesis and tissue homeostasis. Their deregulation impacts the function of several regulatory molecules contributing to tumor initiation and progression. A functional bridge exists between altered gene expression of individual HOX genes and tumorigenesis. This review focuses on how deregulation in the HOX-associated signaling pathways contributes to the metastatic progression in cancer. We discuss their functional significance, clinical implications and ascertain their role as a diagnostic and prognostic biomarker in the various cancer types. Besides, the mechanism of understanding the theoretical underpinning that affects HOX-mediated therapy resistance in cancers has been outlined. The knowledge gained shall pave the way for newer insights into the treatment of cancer.

A Systematic Review on HOX Genes as Potential Biomarkers in Colorectal Cancer: An Emerging Role of HOXB9

Emerging evidence shows that Homeobox (HOX) genes are important in carcinogenesis, and their dysregulation has been linked with metastatic potential and poor prognosis. This review (PROSPERO-CRD42020190953) aims to systematically investigate the role of HOX genes as biomarkers in CRC and the impact of their modulation on tumour growth and progression. The MEDLINE, EMBASE, Web of Science and Cochrane databases were searched for eligible studies exploring two research questions: (a) the clinicopathological and prognostic significance of HOX dysregulation in patients with CRC and (b) the functional role of HOX genes in CRC progression. Twenty-five studies enrolling 3003 CRC patients, showed that aberrant expression of HOX proteins was significantly related to tumour depth, nodal invasion, distant metastases, advanced stage and poor prognosis. A post-hoc meta-analysis on HOXB9 showed that its overexpression was significantly associated with the presence of distant metastases (pooled OR 4.14, 95% CI 1.64–10.43, I² = 0%, p = 0.003). Twenty-two preclinical studies showed that HOX proteins are crucially related to tumour growth and metastatic potential by affecting cell proliferation and altering the expression of epithelial-mesenchymal transition modulators. In conclusion, HOX proteins may play vital roles in CRC progression and are associated with overall survival. HOXB9 may be a critical transcription factor in CRC.

Comprehensive bioinformatics analyses identified Homeobox B9 as a potential prognostic biomarker and therapeutic target for gastric cancer

Background

The Homeobox B (HOXB) family promotes tumor progression, but the mechanism of its action in gastric cancer (GC) is unclear. We sought to identify the HOXB family members that are critical to the prognosis of GC patients.

Methods

The Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, UALCAN, Kaplan-Meier plotter, and the GeneMANIA databases were used to analyze the messenger RNA (mRNA) expression levels, prognostic value, and gene-gene interaction network of the HOXB9 family members in GC. The expression of HOXB9 in GC and its relationship with various clinicopathological parameters and the prognosis of patients were verified by immunohistochemistry.

Results

The expression of HOXB3, HOXB5, HOXB6, HOXB7, HOXB9, and HOXB13 mRNA was significantly upregulated in GC. There was a significant correlation between the upregulation of HOXB3, HOXB5, and HOXB9 mRNA and a low overall survival (OS) rate. The high expression of HOXB7, HOXB9, and HOXB13 mRNA was closely correlated to tumor grade and stage. HOXB9 was the HOXB family member most closely related to the occurrence and development of GC. A further analysis showed that HOXB9 might be involved in deoxyribonucleic acid repair and division regulation. A validation study showed that the advanced cancer group had a higher level of HOXB9 expression than the early cancer group. The high expression of HOXB9 in gastric tissue plays an important role in the survival and prognosis of GC patients.

Conclusions

HOXB family members have different degrees of abnormal expression in GC. High HOXB9 expression in GC tissues was significantly correlated with a worse prognosis. Thus, HOXB9 is a potential novel biomarker and therapeutic target for GC.

Identification of HOXD10 as a Marker of Poor Prognosis in Glioblastoma Multiforme

Purpose

HOXD10 is a tumor modulator that can either be a tumor-suppressor or a tumor-promoting gene. However, the role of HOXD10 in glioblastoma multiforme (GBM) remains unclear.

Methods

Immunohistochemistry (IHC) was applied to detect protein expression of HOXD10 in GBM and normal brain tissue patients. Clinicopathological characteristics with GBM were recorded, and a Kaplan–Meier curve was plotted. Additionally, the mRNA expression of HOXD10 and its effect on prognosis were analyzed using the online tool GEPIA and the Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), and the Gene Expression Omnibus (GEO) databases. Based on the mRNA expression of HOXD10, GBM patients from TCGA database were divided into low- and high-HOXD10 expression groups to analyze the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and construct a lncRNA-miRNA-mRNA network and a protein–protein interaction (PPI) network.

Results

The mRNA expression of HOXD10 was up-regulated in GBM according to GEPIA, while the protein expression of HOXD10 in GBM was down-regulated according to IHC analysis of samples from patients collected from our hospital. Correlation analysis showed that HOXD10 expression was significantly related to IDH1 status. Univariate analysis revealed that low HOXD10 expression, complete surgical resection, postoperative radiotherapy, postoperative temozolomide chemotherapy and IDH1 mutation were all beneficial prognostic factors. Further multivariate analysis revealed that only complete surgical resection and postoperative radiotherapy were independent prognostic factors. GO and KEGG enrichment analyses indicated that HOXD10 expression is mainly involved in cytokine-cytokine receptor interactions. In the ceRNA network, 89 nodes, containing 45 mRNAs, 39 miRNAs and five lncRNAs associated with prognosis were involved. The PPI network revealed a tight interaction between HOXD10 and HOXD8, HOXD9, HOXD11, HOXD13 and HOXB3.

Conclusion

Based on our experimental data, although HOXD10 expression is low in GBM compared with normal brain tissue, GBM patients with high HOXD10 expression have a worse prognosis. HOXD10 may play different or even opposite roles in different stages of GBM occurrence and development. For patients with GBM, HOXD10 may be a valid predictor of prognosis.

Wnt/β-catenin signaling in cancers and targeted therapies

Wnt/β-catenin signaling has been broadly implicated in human cancers and experimental cancer models of animals. Aberrant activation of Wnt/β-catenin signaling is tightly linked with the increment of prevalence, advancement of malignant progression, development of poor prognostics, and even ascendence of the cancer-associated mortality. Early experimental investigations have proposed the theoretical potential that efficient repression of this signaling might provide promising therapeutic choices in managing various types of cancers. Up to date, many therapies targeting Wnt/β-catenin signaling in cancers have been developed, which is assumed to endow clinicians with new opportunities of developing more satisfactory and precise remedies for cancer patients with aberrant Wnt/β-catenin signaling. However, current facts indicate that the clinical translations of Wnt/β-catenin signaling-dependent targeted therapies have faced un-neglectable crises and challenges. Therefore, in this study, we systematically reviewed the most updated knowledge of Wnt/β-catenin signaling in cancers and relatively targeted therapies to generate a clearer and more accurate awareness of both the developmental stage and underlying limitations of Wnt/β-catenin-targeted therapies in cancers. Insights of this study will help readers better understand the roles of Wnt/β-catenin signaling in cancers and provide insights to acknowledge the current opportunities and challenges of targeting this signaling in cancers.

A molecular signature of well-differentiated oral squamous cell carcinoma reveals a resistance mechanism to metronomic chemotherapy and novel therapeutic candidates

Well-differentiated head and neck squamous cell carcinoma (HNSCC), accounts for approximately 10% of all HNSCCs and, while these cases are associated with good prognosis after surgery, these are resistant to chemotherapy. Here we designed a retrospective study to evaluate the effects of histological differentiation on tongue squamous cell carcinoma (TSCC) patients undergoing surgery or metronomic neoadjuvant chemotherapy. The metronomic neoadjuvant chemotherapy significantly improved overall survival of patients with poorly or moderately differentiated tumour, but not those with well-differentiated tumour. Analysis of the Cancer Genome Atlas (TCGA) showed that FAT1 mutations were significantly enriched in more differentiated HNSCC while ASPM mutations were significantly enriched among the poorly differentiated HNSCC. Interestingly, Wnt/β-catenin pathway was activated in well-differentiated HNSCC. Active β-catenin is translocated to the nucleus in the well-differentiated oral squamous cell carcinoma cell lines. Wnt inhibitor, Wnt974, were synergistic with methotrexate in killing well-differentiated oral squamous cell carcinoma (OSCC) cell lines. TCGA data analyses reveal a signature in patients with well-differentiated HNSCC who have no benefits from metronomic neoadjuvant chemotherapy, suggesting that there might be novel nosology and therapeutic candidates for improving HNSCC patient survival. Well-differentiated OSCC is synergistically killed by combination chemotherapy with Wnt inhibitor, making it promising therapeutic candidates.

Distinguishing Rectal Cancer from Colon Cancer Based on the Support Vector Machine Method and RNA-sequencing Data

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Several studies have indicated that rectal cancer is significantly different from colon cancer in terms of treatment, prognosis, and metastasis. Recently, the differential mRNA expression of colon cancer and rectal cancer has received a great deal of attention. The current study aimed to identify significant differences between colon cancer and rectal cancer based on RNA sequencing (RNA-seq) data via support vector machines (SVM). Here, 393 CRC samples from the The Cancer Genome Atlas (TCGA) database were investigated, including 298 patients with colon cancer and 95 with rectal cancer. Following the random forest (RF) analysis of the mRNA expression data, 96 genes such as HOXB13, PRAC, and BCLAF1 were identified and utilized to build the SVM classification model with the Leave-One-Out Cross-validation (LOOCV) algorithm. In the training (n=196) and the validation cohorts (n=197), the accuracy (82.1 % and 82.2 %, respectively) and the AUC (0.87 and 0.91, respectively) indicated that the established optimal SVM classification model distinguished colon cancer from rectal cancer reasonably. However, additional experiments are required to validate the predicted gene expression levels and functions.

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.

Shaping Chromatin States in Prostate Cancer by Pioneer Transcription Factors

The androgen receptor (AR) is a critical therapeutic target in prostate cancer that responds to antagonists in primary disease, but inevitably becomes reactivated, signaling onset of the lethal castration-resistant prostate cancer (CRPC) stage. Epigenomic investigation of the chromatin environment and interacting partners required for AR transcriptional activity has uncovered three pioneer factors that open up chromatin and facilitate AR-driven transcriptional programs. FOXA1, HOXB13, and GATA2 are required for normal AR transcription in prostate epithelial development and for oncogenic AR transcription during prostate carcinogenesis. AR signaling is dependent upon these three pioneer factors both before and after the clinical transition from treatable androgen-dependent disease to untreatable CRPC. Agents targeting their respective DNA binding or downstream chromatin-remodeling events have shown promise in preclinical studies of CRPC. AR-independent functions of FOXA1, HOXB13, and GATA2 are emerging as well. While all three pioneer factors exert effects that promote carcinogenesis, some of their functions may inhibit certain stages of prostate cancer progression. In all, these pioneer factors represent some of the most promising potential therapeutic targets to emerge thus far from the study of the prostate cancer epigenome.

Identification of long non-coding RNA SCARNA9L as a novel molecular target for colorectal cancer

The aim of the present study was to analyze the microarray data of human colorectal cancer (CRC) tissues and identify novel therapeutic targets for CRC. Microarray analysis from the GSE73360 and GSE84984 datasets was performed to identify novel long non-coding RNAs (lncRNAs) that were differentially expressed in human CRC tissues. Additionally, small interfering RNAs were used to deplete the expression of the indicated lncRNAs in cells. Colony-formation, wound-closure, and transwell assays were performed on CRC cells to assess their proliferation and migration capacities. Through microarray analysis, SCARNA9L, SLMO2-ATP5E and LOC100132062 were identified as differentially expressed lncRNAs in CRC tissues. The present study demonstrated that the ablation of SCARNA9L inhibited cell proliferation and arrested the cell cycle of SW480 and SW620 CRC cells. Additionally, depletion of SCARNA9L restrained the migration of CRC cells in vitro. Overall, the present study investigated the potential involvement of SCARNA9L in CRC and suggests SCARNA9L as a potential biomarker.

HOXB13 controls cell state through super-enhancers

Expression of the homeodomain transcription factor HOXB13 has been demonstrated in several malignancies but its role in tumorigenesis remains elusive. We observed high levels of HOXB13 in poorly differentiated pediatric tumors including a highly aggressive childhood neoplasm - malignant rhabdoid tumor. In a xenograft model of rhabdoid tumor, knockout of HOXB13 diminished tumor growth while partial knockdown of HOXB13 promoted differentiation of tumor cells into bone. These results suggest that HOXB13 enhances rhabdoid malignancy by interfering with mesenchymal stem cell differentiation. Consistent with this hypothesis, overexpression of HOXB13 in mesenchymal progenitor cells inhibited adipogenic, myogenic, and osteogenic differentiation. Mechanistically, we demonstrated that HOXB13 binds to super-enhancer regions regulating genes involved in differentiation and tumorigenesis.

Mutation HOXB13 c.853delT in Martinican prostate cancer patients

BACKGROUND

In Martinique, prostate cancer (Pca) incidence rates are nowadays among the highest worldwide with a high incidence of early-onset and familial forms. Despite the demonstration of a strong familial component, identification of the genetic basis for hereditary Pca is challenging. The HOXB13 germline variant G84E (rs138213197) was described in men of European descent with Pca risk.

METHODS

To investigate the potential involvement of HOXB13 mutations in Martinique, we performed sequencing of the HOXB13 coding regions of 46 index cases with early-onset Pca (before the age of 51). Additional breast cancers and controls were performed. All cancer cases analyzed in this study have been observed in the context of genetic counseling.

RESULTS

We identified a rare heterozygous germline variant c.853delT (p.Ter285Lysfs) rs77179853, reported only among patients of African ancestry with a minor allele frequency of 3.2%. This variant is a stop loss reported only among patients of African ancestry with a frequency of 0.2%.

CONCLUSION

In conclusion, we think that this study provides supplementary arguments that HOXB13 variants are involved in Pca.

Right and left-sided colon cancers - specificity of molecular mechanisms in tumorigenesis and progression

Background

Given the differences in embryonic origin, vascular and nervous supplies, microbiotic burden, and main physiological functions of left and right colons, tumor location is increasingly suggested to dictate tumor behavior affecting pathology, progression and prognosis. Right-sided colon cancers arise in the cecum, ascending colon, hepatic flexure and/or transverse colon, while left-sided colon cancers arise in the splenic flexure, descending, and/or sigmoid colon. In contrast to prior reports, we attempt to delineate programs of tumorigenesis independently for each side.

Methods

Four hundred and eleven samples were extracted from The Cancer Genome Atlas-COAD cohort, based on a conservative sample inclusion criterion. Each side was independently analyzed with respect to their respective normal tissue, at the level of transcription, post-transcription, miRNA control and methylation in both a stage specific and stage-agnostic manner.

Results

Our results indicate a suppression of enzymes involved in various stages of carcinogen breakdown including CYP2C8, CYP4F12, GSTA1, and UGT1A within right colon tumors. This implies its reduced capacity to detoxify carcinogens, contributing to a genotoxic tumor environment, and subsequently a more aggressive phenotype. Additionally, we highlight a crucial nexus between calcium homeostasis (sensing, mobilization and absorption) and immune/GPCR signaling within left-sided tumors, possibly contributing to its reduced proliferative and metastatic potential. Interestingly, two genes SLC6A4 and HOXB13 show opposing regulatory trends within right and left tumors. Post-transcriptional regulation mediated by both RNA-binding proteins (e.g. NKRF (in left) and MSI2 (in right)) and miRNAs (e.g. miR-29a (in left); miR-155, miR181-d, miR-576 and miR23a (in right)) appear to exhibit side-specificity in control of their target transcripts and is pronounced in right colon tumors. Additionally, methylation results depict location-specific differences, with increased hypomethylation in open seas within left tumors, and increased hypermethylation of CpG islands within right tumors.

Conclusions

Differences in molecular mechanisms captured here highlight distinctions in tumorigenesis and progression between left and right colon tumors, which will serve as the basis for future studies, influencing the efficacies of existing and future diagnostic, prognostic and therapeutic interventions.

HOXB13 expression is correlated with hepatic inflammatory activity of patients with hepatic fibrosis

Liver fibrosis is a common pathological process of chronic hepatic injury, preceded by the chronic inflammation. The homeobox B13 (HOXB13) gene, a member of HOX family, plays diverse biological roles in embryonic development, carcinogenesis, and many inflammatory diseases. However, the expression of HOXB13 in chronic liver diseases including hepatic fibrosis remains to be defined. In present study, 55 patients with hepatic fibrosis, 15 patients of hepatocellular carcinoma, and 17 healthy controls were enrolled in this study. Pathological specimens were collected through liver biopsy or surgical resection. The degree of hepatic inflammation (G0-G4) and fibrosis (S0-S4) of hepatic fibrosis was scored based on the modified histology activity index. Intrahepatic HOXB13 expression was analyzed using immunohistochemistry analysis. Compared with healthy subjects, both patients with hepatic fibrosis and patients with hepatocellular carcinoma exhibited significant accumulations of HOXB13+ cells in the liver (p < 0.05). Additionally, the number of HOXB13+ cell was significantly elevated along with the increment of hepatic inflammatory activities, but not fibrosis stages, among these liver fibrosis samples (p < 0.01). Furthermore, the quantity of HOXB13+ cells were also positively correlated with hepatic enzymes, alanine transaminase (r = 0.299, p = 0.041) and aspartate aminotransferase (r = 0.317, p = 0.013) in our cohort of hepatic fibrosis. In conclusion, our study identified a strong hepatic expression of HOXB13 among patients with hepatic fibrosis, which strongly associated with the degree of hepatic inflammatory activity for patients with hepatic fibrosis, suggesting an important role of HOXB13 during the pathogenesis of liver fibrogenesis.

HoxB13 expression in ductal type adenocarcinoma of prostate: clinicopathologic characteristics and its utility as potential diagnostic marker

The histologic criteria and selective biomarkers of prostate ductal type adenocarcinoma (DAC) are relatively unknown compared to that known about acinar type adenocarcinoma (AAC). It is known that genetic alteration in Hox13 gene is associated with carcinogenesis of prostate cancer. In this study, we investigated clinicopathologic characteristics of HoxB13 expression in prostate cancer and compared clinicopathologic profiles of DAC and AAC of prostate. After slide review, some morphological variants of DAC, equivalent to Gleason pattern 3 and 5 of AAC were identified. High level of HoxB13 expression was identified in 46.5% (46 out of 99 cases) and 39.2% (31 out of 79 cases) of cases that belong to the training set and test set, respectively. In the training set, high level of HoxB13 expression was significantly correlated with DAC (P < 0.001), higher Gleason score (P < 0.001), advanced pathologic T stage (P = 0.010), and occurrence of biochemical recurrence (BCR; P < 0.001). The test set confirmed that high level of HoxB13 expression was associated with DAC (P < 0.001), higher Gleason score (P = 0.001), advanced pathologic T stage (P < 0.001), and occurrence of BCR (P < 0.001). Our findings suggest that HoxB13 may be a useful diagnostic marker for detection of DAC and a prognostic marker for prediction of BCR.

Tumor-suppressive function and mechanism of HOXB13 in right-sided colon cancer

Right-sided colon cancer (RCC) and left-sided colon cancer (LCC) differ in their clinical and molecular features. An investigation of differentially expressed genes (DEGs) between RCC and LCC could contribute to targeted therapy for colon cancer, especially RCC, which has a poor prognosis. Here, we identified HOXB13, which was significantly less expressed in RCC than in LCC and associated with prognosis in RCC, by using 5 datasets from the Gene Expression Omnibus (GEO). Tissue sample analysis showed that HOXB13 was differentially expressed between normal and only RCC tumor tissues. HOXB13 inhibited colon cancer cell proliferation and induced apoptosis both in vitro and in vivo. Furthermore, we found that HOXB13 might be regulated by DNMT3B and suppress C-myc expression to exert antitumor effects via β-catenin/TCF4 signals in RCC. In conclusion, the current study is the first to demonstrate that HOXB13 has a tumor-suppressive effect in RCC. High expression levels of HOXB13 are associated with prolonged overall survival in patients with RCC. The DNMT3B-HOXB13-C-myc signaling axis might be a molecular target for the treatment of RCC.

HOX family transcription factors: Related signaling pathways and post-translational modifications in cancer

HOX family transcription factors belong to a highly conserved subgroup of the homeobox superfamily that determines cellular fates in embryonic morphogenesis and the maintenance of adult tissue architecture. HOX family transcription factors play key roles in numerous cellular processes including cell growth, differentiation, apoptosis, motility, and angiogenesis. As tumor promoters or suppressors HOX family members have been reported to be closely related with a variety of cancers. They closely regulate tumor initiation and growth, invasion and metastasis, angiogenesis, anti-cancer drug resistance and stem cell origin. Here, we firstly described the pivotal roles of HOX transcription factors in tumorigenesis. Then, we summarized the main signaling pathways regulated by HOX transcription factors, including Wnt/β-catenin, transforming growth factor β, mitogen-activated protein kinase, phosphoinositide 3-kinase/Akt, and nuclear factor-κB signalings. Finally, we outlined the important post-translational modifications of HOX transcription factors and their regulation in cancers. Future research directions on the HOX transcription factors are also discussed.

Analysis of lncRNA-miRNA-mRNA Interactions in Hyper-proliferative Human Pulmonary Arterial Smooth Muscle Cells

We previously reported enhanced proliferation of smooth muscle cells on the combined exposure of HIV proteins and cocaine leading to the development of HIV-pulmonary arterial hypertension. Here, we attempt to comprehensively understand the interactions between long noncoding RNAs (lncRNAs), mRNAs and micro-RNAs (miRNAs) to determine their role in smooth muscle hyperplasia. Differential expression of lncRNAs, mRNAs and miRNAs were obtained by microarray and small-RNA sequencing from HPASMCs treated with and without cocaine and/or HIV-Tat. LncRNA to mRNA associations were conjectured by analyzing their genomic proximity and by interrogating their association to vascular diseases and cancer co-expression patterns reported in the relevant databases. Neuro-active ligand receptor signaling, Ras signaling and PI3-Akt pathway were among the top pathways enriched in either differentially expressed mRNAs or mRNAs associated to lncRNAs. HPASMC with combined exposure to cocaine and Tat (C + T) vs control identified the following top lncRNA-mRNA pairs, ENST00000495536-HOXB13, T216482-CBL, ENST00000602736-GDF7, and, TCONS_00020413-RND1. Many of the down-regulated miRNAs in the HPASMCs treated with C + T were found to be anti-proliferative and targets of up-regulated lncRNAs targeting up-regulated mRNAs, including down-regulation of miR-185, -491 and up-regulation of corresponding ENST00000585387. Specific knock down of the selected lncRNAs highlighted the importance of non-coding RNAs in smooth muscle hyperplasia.

Paralogous HOX13 Genes in Human Cancers

Hox genes (HOX in humans), an evolutionary preserved gene family, are key determinants of embryonic development and cell memory gene program. Hox genes are organized in four clusters on four chromosomal loci aligned in 13 paralogous groups based on sequence homology (Hox gene network). During development Hox genes are transcribed, according to the rule of “spatio-temporal collinearity”, with early regulators of anterior body regions located at the 3’ end of each Hox cluster and the later regulators of posterior body regions placed at the distal 5’ end. The onset of 3’ Hox gene activation is determined by Wingless-type MMTV integration site family (Wnt) signaling, whereas 5’ Hox activation is due to paralogous group 13 genes, which act as posterior-inhibitors of more anterior Hox proteins (posterior prevalence). Deregulation of HOX genes is associated with developmental abnormalities and different human diseases. Paralogous HOX13 genes (HOX A13, HOX B13, HOX C13 and HOX D13) also play a relevant role in tumor development and progression. In this review, we will discuss the role of paralogous HOX13 genes regarding their regulatory mechanisms during carcinogenesis and tumor progression and their use as biomarkers for cancer diagnosis and treatment.

HOXB13 promotes proliferation, migration, and invasion of glioblastoma through transcriptional upregulation of lncRNA HOXC-AS3

HOXB13 exerts a close relation in several human cancers. This study explored the role of HOXB13 in glioblastoma (GBM), a brain tissue with the highest aggressive rate and mortality in adults. Through microarray and immunohistochemistry analyses, HOXB13 was highly expressed in GBM tissues. Furthermore, we showed that high-level expression of HOXB13 in GBM was associated with worse survival, suggesting that HOXB13 could be a prognostic marker for patients with GBM. GBM cells U87 and U251 overexpressing HOXB13 showed enhanced proliferation, migration, and invasion relative to the control cells, while knockdown of HOXB13 led to decreased cell proliferation, migration, and invasion abilities. In addition, dual-luciferase report assay, chromatin immunoprecipitation assay, and quantitative real-time polymerase chain reaction data showed that HOXB13 directly bound to HOXC-AS3 promoter. HOXC-AS3 was involved in HOXB13-induced proliferation, migration, and invasion of GBM cells. In summary, this study revealed the prognostic potential of HOXB13 in GBM. We believed that HOXB13/HOXC-AS3 signaling axis can be served as therapeutic targets for this highly aggressive cancer.

The Role of HOX Transcription Factors in Cancer Predisposition and Progression

Homeobox (HOX) transcription factors, encoded by a subset of homeodomain superfamily genes, play pivotal roles in many aspects of cellular physiology, embryonic development, and tissue homeostasis. Findings over the past decade have revealed that mutations in HOX genes can lead to increased cancer predisposition, and HOX genes might mediate the effect of many other cancer susceptibility factors by recognizing or executing altered genetic information. Remarkably, several lines of evidence highlight the interplays between HOX transcription factors and cancer risk loci discovered by genome-wide association studies, thereby gaining molecular and biological insight into cancer etiology. In addition, deregulated HOX gene expression impacts various aspects of cancer progression, including tumor angiogenesis, cell autophagy, proliferation, apoptosis, tumor cell migration, and metabolism. In this review, we will discuss the fundamental roles of HOX genes in cancer susceptibility and progression, highlighting multiple molecular mechanisms of HOX involved gene misregulation, as well as their potential implications in clinical practice.

Posterior HOX genes and HOTAIR expression in the proximal and distal colon cancer pathogenesis

BACKGROUND

Increasing evidences showed that the location of the primary tumor on the right (proximal) or left (distal) side of the colon have a prognostic/predictive value for colon cancer patients. However, the understanding of the molecular mechanisms that contribute to the pathogenesis in different location of colon is still unclear. Probably an important role could be played by genes that control the spatial-temporal development of bodily structures, such as HOX genes.

METHODS

The main purpose of this study was to analyze the expression of the paralogous 13 HOX genes and of the HOX regulating lncRNA HOTAIR in distal and proximal CRC cases. We have carried out a Tissue Micro Array with left and right CRC samples associated with all clinical-pathological parameters of patients. The expression of HOX genes was evaluated by immunohistochemistry and the staining of HOTAIR was performed by in situ hybridization using a specifically designed LNA probe.

RESULTS

All paralogous 13 HOX genes and HOTAIR are silent in normal tissue and expressed in CRC samples. HOXB13, HOXC13 and HOTAIR showed a statistical association with lymph nodes metastasis (p value = 0.003, p value = 0.05, p value = 0.04). HOXB13, HOXC13 and lncRNA HOTAIR are overexpressed in right CRCs samples (p value < 0 and p value = 0.021). HOTAIR is also strongly correlated with HOXB13 (p value = 0.02) and HOXC13 (p value = 0.042) expression.

CONCLUSIONS

Our data highlighted an important role of posterior HOX genes in colorectal cancer carcinogenesis. Specifically, the aberrant expression of the HOXB13, HOXC13 and HOTAIR in proximal colon cancers could add an important dowel in understanding molecular mechanisms related to tumor pathogenesis in this location.

HOXD10 silencing suppresses human fibroblast-like synoviocyte migration in rheumatoid arthritis via downregulation of the p38/JNK pathway

Homeobox D10 (HOXD10) belongs to the human homeobox (HOX) gene family, and the homologous protein encoded by HOX primarily controls cell differentiation and morphogenesis during embryonic development. The current study aimed to explore the roles and mechanisms of HOXD10 in the migration of human fibroblast-like synoviocytes in rheumatoid arthritis (RAFLS). Cell counting kit-8, cell migration and wound healing assays were performed to examine the cell viability and migration, respectively. Western blot and reverse transcription-quantitative polymerase chain reaction assays were used to evaluate the association between mRNA and protein expression levels. The results revealed HOXD10 expression was upregulated in tissues from patients with RA. HOXD10 silencing inhibited the viability of RAFLS. In addition, HOXD10 silencing suppressed the migration of RAFLS through modulating the expression of cadherin-11, N-cadherin, E-cadherin, vimentin, zonula occludens-1, integrinβ1 and paxillin. In conclusion, HOXD10 silencing downregulates the p38/c-Jun N-terminal kinase signaling pathway, which in turn may suppress the migration of RAFLS.

Differential preventive activity of sulindac and atorvastatin in Apc+/Min-FCCCmice with or without colorectal adenomas

OBJECTIVE

The response of subjects to preventive intervention is heterogeneous. The goal of this study was to determine if the efficacy of a chemopreventive agent differs in non-tumour-bearing animals versus those with colorectal tumours. Sulindac and/or atorvastatin was administered to Apc^+/Min-FCCC mice with known tumour-bearing status at treatment initiation.

DESIGN

Male mice (6-8 weeks old) underwent colonoscopy and received control chow or chow with sulindac (300 ppm), atorvastatin (100 ppm) or sulindac/atorvastatin. Tissues were collected from mice treated for 14 weeks (histopathology) or 7 days (gene expression). Cell cycle analyses were performed on SW480 colon carcinoma cells treated with sulindac, atorvastatin or both.

RESULTS

The multiplicity of colorectal adenomas in untreated mice bearing tumours at baseline was 3.6-fold higher than that of mice that were tumour free at baseline (P=0.002). Atorvastatin completely inhibited the formation of microadenomas in mice that were tumour free at baseline (P=0.018) and altered the expression of genes associated with stem/progenitor cells. Treatment of tumour-bearing mice with sulindac/atorvastatin led to a 43% reduction in the multiplicity of colorectal adenomas versus untreated tumour-bearing mice (P=0.049). Sulindac/atorvastatin increased the expression of Hoxb13 and Rprm significantly, suggesting the importance of cell cycle regulation in tumour inhibition. Treatment of SW480 cells with sulindac/atorvastatin led to cell cycle arrest (G0/G1).

CONCLUSIONS

The tumour status of animals at treatment initiation dictates response to therapeutic intervention. Atorvastatin eliminated microadenomas in tumour-free mice. The tumour inhibition observed with Sul/Atorva in tumour-bearing mice was greater than that achieved with each agent.

HOXB13 expression and promoter methylation as a candidate biomarker in gastric cancer

Homeobox b13 (HOXB13) is considered to be a tumor suppressor gene in multiple types of human cancer. The present study aimed to identify the difference in expression of HOXB13 mRNA between gastric cancer (GC) tissues and corresponding non-malignant gastric tissues. The clinical significance of HOXB13 mRNA expression was also assessed in GC and a potential association between HOXB13 mRNA expression and DNA promoter methylation was observed. The expression of HOXB13 mRNA was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and HOXB13 methylation status was assessed by methylation-specific PCR (MSP) in 5 GC cell lines and 85 paired GC and normal gastric tissues. Kaplan-Meier survival curves were used to assess the survival of patients with GC. HOXB13 mRNA expression was significantly lower in primary GC tissues than in corresponding nonmalignant gastric tissues, and decreased HOXB13 expression was associated with poorer differentiation, lymph node metastasis, invasion depth and Tumor-Node-Metastasis (TNM) stage. Kaplan-Meier survival analysis demonstrated that HOXB13 mRNA expression was a significant prognostic indicator of GC patient survival. Furthermore, MSP revealed that the proportion of GC samples with hypermethylated HOXB13 (60.0%, 51/85) was increased compared with the corresponding nonmalignant gastric tissues (11.8%, 10/85). Decreased HOXB13 mRNA expression was due to DNA hypermethylation as following treatment with the DNA methyltransferase inhibitor 5-Aza-dC, HOXB13 expression in the GC MKN-45 cell line was upregulated. The results of the present study indicate that decreased expression of HOXB13 mRNA was associated with tumor differentiation, depth of invasion, lymph node metastases and TNM stage in GC, and it was a significant poor prognostic factor for patients with GC. Aberrant DNA promoter methylation was a crucial reason for the downregulation of HOXB13 mRNA expression.

Multi-omics Approach Reveals Distinct Differences in Left- and Right-Sided Colon Cancer

Increasing evidence suggests that left-sided colon cancer (LCC) and right-sided colon cancer (RCC) are emerging as two different colorectal cancer types with distinct clinical characteristics. However, the discrepancy in the underlying molecular event between these types of cancer has not been thoroughly elucidated to date and warrants comprehensive investigation. To this end, an integrated dataset from The Cancer Genome Atlas was used to compare and contrast LCC and RCC, covering mutation, DNA methylation, gene expression, and miRNA. Briefly, the signaling pathway cross-talk is more prevalent in RCC than LCC, such as RCC-specific PI3K pathway, which often exhibits cross-talk with the RAS and P53 pathways. Meanwhile, methylation signatures revealed that RCC was hypermethylated relative to LCC. In addition, differentially expressed genes (n = 253) and differentially expressed miRNAs (n = 16) were determined between LCC and RCC. Especially for Prostate Cancer Susceptibility Candidate 1 (PRAC1), a gene that was closely associated with hypermethylation, was the top significantly downregulated gene in RCC. Multi-omics comparison of LCC and RCC suggests that there are more aggressive markers in RCC and that tumor heterogeneity occurs within the location-based subtypes of colon cancer. These results clarify the debate regarding the conflicting prognosis between LCC and RCC, as proposed by different studies.Implications: The underlying molecular features present in LCC and RCC identified in this study are beneficial for adopting reasonable therapeutic approaches to prolong overall survival and progression-free survival in colorectal cancer patients. Mol Cancer Res; 16(3); 476-85. ©2017 AACR.

Mechanisms of colitis-accelerated colon carcinogenesis and its prevention with the combination of aspirin and curcumin: Transcriptomic analysis using RNA-seq

Colorectal cancer (CRC) remains the leading cause of cancer-related death in the world. Aspirin (ASA) and curcumin (CUR) are widely investigated chemopreventive candidates for CRC. However, the precise mechanisms of their action and their combinatorial effects have not been evaluated. The purpose of the present study was to determine the effect of ASA, CUR, and their combination in azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colitis-accelerated colorectal cancer (CAC). We also aimed to characterize the differential gene expression profiles in AOM/DSS-induced tumors as well as in tumors modulated by ASA and CUR using RNA-seq. Diets supplemented with 0.02% ASA, 2% CUR or 0.01% ASA+1% CUR were given to mice from 1week prior to the AOM injection until the experiment was terminated 22weeks after AOM initiation. Our results showed that CUR had a superior inhibitory effect in colon tumorigenesis compared to that of ASA. The combination of ASA and CUR at a lower dose exhibited similar efficacy to that of a higher dose of CUR at 2%. RNA isolated from colonic tissue from the control group and from tumor samples from the experimental groups was subjected to RNA-seq. Transcriptomic analysis suggested that the low-dose combination of ASA and CUR modulated larger gene sets than the single treatment. These differentially expressed genes were situated in several canonical pathways important in the inflammatory network and liver metastasis in CAC. We identified a small subset of genes as potential molecular targets involved in the preventive action of the combination of ASA and CUR. Taken together, the current results provide the first evidence in support of the chemopreventive effect of a low-dose combination of ASA and CUR in CAC. Moreover, the transcriptional profile obtained in our study may provide a framework for identifying the mechanisms underlying the carcinogenesis process from normal colonic tissue to tumor development as well as the cancer inhibitory effects and potential molecular targets of ASA and CUR.

Exploration of the molecular mechanism of prostate cancer based on mRNA and miRNA expression profiles

Prostate cancer, the second most common cancer in men, has been rarely explored by integrating mRNA and miRNA expression profiles. In this study, we combined two mRNA expression datasets and six documented miRNAs to uncover the comprehensive molecular mechanism of prostate cancer. Results showed that a total of 30 genes were significantly differentially expressed in 49 tumor samples by comparing with 22 normal samples. Importantly, all samples from the two datasets can be clearly classified into two groups, tumor group and normal group, based on the selected differentially expressed genes (DEGs). The miRNA–mRNA regulation network indicated that 4 out of 30 DEGs can be regulated by three miRNAs. In addition, prognostic performance validation using in silico databases showed that the DEGs can significantly differentiate between low-risk and high-risk prostate cancer. In summary, multiple biological processes are probably involved in the development and progression of prostate cancer. First, dysregulation of SV2 can regulate transporter and transmembrane transporter activity and then provide the necessary nutrients for tumor cell proliferation. Second, HOXD10 can induce cell proliferation via TCF-4. Finally, dysregulation of CACNA1D can further suppress tumor apoptosis in prostate cancer. The identification of critical genes and valuable biological processes can be useful for the understanding of the molecular mechanism of prostate cancer.

The regulation of β-catenin activity and function in cancer: therapeutic opportunities

Wnt/β-catenin signaling is an evolutionarily conserved and versatile pathway that is known to be involved in embryonic development, tissue homeostasis and a wide variety of human diseases. Aberrant activation of this pathway gives rise to the accumulation of β-catenin in the nucleus and promotes the transcription of many oncogenes such as c-Myc and CyclinD-1. As a result, it contributes to carcinogenesis and tumor progression of several cancers, including colon cancer, hepatocellular carcinoma, pancreatic cancer, lung cancer and ovarian cancer. β-Catenin is a pivotal component of the Wnt signaling pathway and it is tightly regulated at three hierarchical levels: protein stability, subcellular localization and transcriptional activity. Uncovering the regulatory mechanisms of β-catenin will provide new insights into the pathogenesis of cancer and other diseases, as well as new therapeutic strategies against these diseases. In this review we dissect the concrete regulatory mechanisms of β-catenin from three aspects mentioned above. Then we focus on the role of β-catenin in cancer initiation, progression, dormancy, immunity and cancer stem cell maintenance. At last, we summarize the recent progress in the development of agents for the pharmacological modulation of β-catenin activity in cancer therapy.

Oncogenic mechanisms of HOXB13 missense mutations in prostate carcinogenesis

The recurrent germline mutation HOXB13 p.(Gly84Glu) (G84E) has recently been identified as a risk factor for prostate cancer. In a recent study, we have performed full sequencing of the HOXB13 gene in 462 Portuguese prostate cancer patients with early-onset and/or familial/hereditary disease, and identified two novel missense mutations, p.(Ala128Asp) (A128D) and p.(Phe240Leu) (F240L), that were predicted to be damaging to protein function. In the present work we aimed to investigate the potential oncogenic role of these mutations, comparing to that of the recurrent G84E mutation and wild-type HOXB13. We induced site-directed mutagenesis in a HOXB13 expression vector and established in vitro cell models of prostate carcinogenesis with stable overexpression of either the wild-type or the mutated HOXB13 variants. By performing in vitro assays we observed that, while the wild-type promotes proliferation, also observed with the F240L variant along with a decrease in apoptosis, the A128D mutation decreases apoptosis and promotes anchorage independent growth. No phenotypic impact was observed for the G84E mutation in the cell line model used. Our data show that specific HOXB13 mutations are involved in the acquisition of different cancer-associated capabilities and further support an oncogenic role for HOXB13 in prostate carcinogenesis.

Association between germline homeobox B13 (HOXB13) G84E allele and prostate cancer susceptibility: a meta-analysis and trial sequential analysis

Germline HOXB13 G84E mutation (rs138213197) has been described associated with prostate cancer (PCa) susceptibility but results of different studies are inconsistent. We conducted this meta-analysis to evaluate the specific role of this mutation. Relevant available studies were identified by searching the databases Pubmed, Embase and Web of Science. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to measure the strength of the association. Subgroup analysis were performed to evaluate the specific role of rs138213197 in disease aggressiveness, diagnostic age and family history. Furthermore, trial sequential analysis (TSA) was conducted for the first time to estimate whether the evidence of the results is sufficient. Our results indicated that significant increased PCa susceptibility was associated with rs138213197 compared with non-carriers (OR = 3.38, 95% CI: 2.45-4.66). Besides, in subgroup analysis, HOXB13 G84E variant was obviously associated with early onset (OR = 2.90, 95% CI: 2.24-3.75), affected relatives (OR = 2.60, 95% CI 2.19-3.10) and highly aggressive disease (OR = 2.38, 95% CI 1.84-3.08). By TSA, the findings in the current study were based on sufficient evidence. Therefore, our results indicated that the G84E mutation in HOXB13 gene might increase susceptibility to PCa.

Impact of homeobox genes in gastrointestinal cancer

Homeobox genes, including HOX and non-HOX genes, have been identified to be expressed aberrantly in solid tumors. In gastrointestinal (GI) cancers, most studies have focused on the function of non-HOX genes including caudal-related homeobox transcription factor 1 (CDX1) and CDX2. CDX2 is a crucial factor in the development of pre-cancerous lesions such as Barrett’s esophagus or intestinal metaplasia in the stomach, and its tumor suppressive role has been investigated in colorectal cancers. Recently, several HOX genes were reported to have specific roles in GI cancers; for example, HOXA13 in esophageal squamous cell cancer and HOXB7 in stomach and colorectal cancers. HOXD10 is upregulated in colorectal cancer while it is silenced epigenetically in gastric cancer. Thus, it is essential to examine the differential expression pattern of various homeobox genes in specific tumor types or cell lineages, and understand their underlying mechanisms. In this review, we summarize the available research on homeobox genes and present their potential value for the prediction of prognosis in GI cancers.

Germline HOXB13 p.Gly84Glu mutation and cancer susceptibility: a pooled analysis of 25 epidemiological studies with 145,257 participates

Numerous studies have investigated association between the germline HOXB13 p.Gly84Glu mutation and cancer risk. However, the results were inconsistent. Herein, we performed this meta-analysis to get a precise conclusion of the associations. A comprehensive literature search was conducted through Medline (mainly Pubmed), Embase, Cochrane Library databases. Crude odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated by STATA 12.1 software to evaluate the association of HOXB13 p.Gly84Glu mutation and cancer susceptibility. Then, 25 studies including 51,390 cases and 93,867 controls were included, and there was significant association between HOXB13 p.Gly84Glu mutation and overall cancer risk (OR = 2.872, 95% CI = 2.121-3.888, P < 0.001), particularly in prostate cancer (OR = 3.248, 95% CI = 2.313-4.560, P < 0.001), while no association was found in breast (OR = 1.424, 95% CI = 0.776-2.613, P = 0.253) and colorectal cancers (OR = 2.070, 95% CI = 0.485-8.841, P = 0.326). When we stratified analysis by ethnicity, significant association was found in Caucasians (OR = 2.673, 95%CI = 1.920-3.720, P < 0.001). Further well-designed with large samples and other various cancers should be performed to validate our results.

Polycomb Complex PRC1 Preserves Intestinal Stem Cell Identity by Sustaining Wnt/β-Catenin Transcriptional Activity

Polycomb repressive complexes (PRCs) are among the most important gatekeepers of establishing and maintaining cell identity in metazoans. PRC1, which plays a dominant role in this context, executes its functions via multiple subcomplexes, which all contribute to H2AK119 mono-ubiquitination (H2Aubq). Despite our comprehensive knowledge of PRC1-dependent H2Aubq in embryonic stem cells and during early development, its role in adult stem cells still remains poorly characterized. Here we show that PRC1 activity is required for the integrity of the intestinal epithelium, regulating stem cell self-renewal via a cell-autonomous mechanism that is independent from Cdkn2a expression. By dissecting the PRC1-dependent transcription program in intestinal stem cells, we demonstrate that PRC1 represses a large number of non-lineage-specific transcription factors that directly affect β-catenin/Tcf transcriptional activity. Our data reveal that PRC1 preserves Wnt/β-catenin activity in adult stem cells to maintain intestinal homeostasis and supports tumor formation induced by the constitutive activation of this pathway.

The HOX-Apoptosis Regulatory Interplay in Development and Disease

Apoptosis is a cellular suicide program, which is on the one hand used to remove superfluous cells thereby promoting tissue or organ morphogenesis. On the other hand, the programmed killing of cells is also critical when potentially harmful cells emerge in a developing or adult organism thereby endangering survival. Due to its critical role apoptosis is tightly controlled, however so far, its regulation on the transcriptional level is less studied and understood. Hox genes, a highly conserved gene family encoding homeodomain transcription factors, have crucial roles in development. One of their prominent functions is to shape animal body plans by eliciting different developmental programs along the anterior-posterior axis. To this end, Hox proteins transcriptionally regulate numerous processes in a coordinated manner, including cell-type specification, differentiation, motility, proliferation as well as apoptosis. In this review, we will focus on how Hox proteins control organismal morphology and function by regulating the apoptotic machinery. We will first focus on well-established paradigms of Hox-apoptosis interactions and summarize how Hox transcription factors control morphological outputs and differentially shape tissues along the anterior-posterior axis by fine-tuning apoptosis in a healthy organism. We will then discuss the consequences when this interaction is disturbed and will conclude with some ideas and concepts emerging from these studies.

Overexpression of homeobox B-13 correlates with angiogenesis, aberrant expression of EMT markers, aggressive characteristics and poor prognosis in pancreatic carcinoma

To investigate the expression of homeobox B (Hoxb)-13 and analyze its relationship with tumor angiogenesis, epithelial-mesenchymal transition (EMT)-associated markers (E-cadherin and vimentin), clinicopathologic data and prognosis in pancreatic carcinoma. Immunohistochemistry was applied to determine the level of Hoxb-13 expression in tumor tissues and surrounding non-tumor tissues from 85 subjects with pancreatic carcinoma. Besides, vascular endothelial growth factor (VEGF), CD31, E-cadherin and vimentin were also detected in tumor tissues by immunostaining. We found that the level of Hoxb-13 expression was significantly higher in pancreatic carcinoma tissues than in paracarcinomatous tissues (P < 0.05). Hoxb-13 staining was positively correlated with VEGF (r = 0.429, P < 0.001) and microvessel density (MVD) (r = 0.454, P < 0.001). Likewise, Hoxb-13 staining was positively correlated with vimentin (r = 0.448, P < 0.001); while it was negatively correlated with E-cadherin (r = -0.405, P < 0.001). High Hoxb-13 expression was associated with aggressive clinicopathological characteristics, worse disease-free survival (DFS) (P < 0.001) and worse overall survival (OS) (P < 0.001). Multivariate analysis showed that Hoxb-13 was an independent predictor for poor DFS (P < 0.001) and OS (P = 0.002). In conclusion, our data show that overexpressed Hoxb-13 is correlated with tumor angiogenesis, aberrant expression of EMT-associated markers and aggressive clinicopathological characteristics, and serves as a promising marker for unfavourable prognosis in pancreatic carcinoma.

Dysregulation of the homeobox transcription factor gene HOXB13: role in prostate cancer

Prostate cancer (PC) is the most common noncutaneous cancer in men, and epidemiological studies suggest that about 40% of PC risk is heritable. Linkage analyses in hereditary PC families have identified multiple putative loci. However, until recently, identification of specific risk alleles has proven elusive. Cooney et al used linkage mapping and segregation analysis to identify a putative risk locus on chromosome 17q21-22. In search of causative variant(s) in genes from the candidate region, a novel, potentially deleterious G84E substitution in homeobox transcription factor gene HOXB13 was observed in multiple hereditary PC families. In follow-up testing, the G84E allele was enriched in cases, especially those with an early diagnosis or positive family history of disease. This finding was replicated by others, confirming HOXB13 as a PC risk gene. The HOXB13 protein plays diverse biological roles in embryonic development and terminally differentiated tissue. In tumor cell lines, HOXB13 participates in a number of biological functions, including coactivation and localization of the androgen receptor and FOXA1. However, no consensus role has emerged and many questions remain. All HOXB13 variants with a proposed role in PC risk are predicted to damage the protein and lie in domains that are highly conserved across species. The G84E variant has the strongest epidemiological support and lies in a highly conserved MEIS protein-binding domain, which binds cofactors required for activation. On the basis of epidemiological and biological data, the G84E variant likely modulates the interaction between the HOXB13 protein and the androgen receptor, as well as affecting FOXA1-mediated transcriptional programming. However, further studies of the mutated protein are required to clarify the mechanisms by which this translates into PC risk.

HOXB13 regulates the prostate-derived Ets factor: implications for prostate cancer cell invasion

HOXB13 has been shown to enhance the invasive potential of breast and endometrial tumors. HOXB13 is also abundant in castration-resistant prostate tumors. To determine the invasive potential of HOXB13 in prostate tumors, highly metastatic PC3 prostate cancer cells were manipulated to express HOXB13 and/or the prostate-derived Ets factor (PDEF). The PDEF is believed to reduce the invasive potential of various tumors, including prostate tumors. To further demonstrate the functional correlation between HOXB13 and PDEF, transwell invasion and gelatin zymography assays were performed. In addition, the western blot analysis was used to demonstrate the expression of PDEF target proteins involved in cancer cell migration and invasion, MMP-9 and survivin. According to the results, HOXB13 promoted PC3 cell migration and invasion. The DNA microarray analysis demonstrated that HOXB13 significantly suppressed the expression of the PDEF. Accordingly, the expression of MMP-9 and survivin was regulated by HOXB13. In addition, HOXB13 promoted the invasive potential of PC3 cells while inhibiting the PDEF. The coexpression of HOXB13 and the PDEF led to moderate retardation of the number of invasive cells, indicating that HOXB13 functionally counteracted cell invasion by reducing PDEF expression. The western blot analysis demonstrated that HOXB13 counteracted the PDEF-mediated inhibition of the expression of PDEF target proteins such as MMP-9 and survivin. The results suggest that the HOXB13-mediated promotion of tumor cell invasion is accomplished mainly through the downregulation of PDEF expression.

High-level expression of HOXB13 is closely associated with tumor angiogenesis and poor prognosis of hepatocellular carcinoma

Homeobox B13 (HOXB13) is generally considered as a crucial regulator of terminal cellular differentiation. More recently, the absent or aberrant expression of HOXB13 has been increasingly implicated in cancer development and metastasis. However, the expression of HOXB13 in hepatocellular carcinoma (HCC) and its correlation with tumor angiogenesis and prognosis still remain unclear. The aim of the study was to evaluate the expression of HOXB13 in patients with HCC and explore the relationship of HOXB13 expression with clinicopathologic factors, tumor angiogenesis and prognosis. Immunohistochemistry was performed to determine the expression of HOXB13 in HCC and corresponding paracarcinomatous tissues from 72 patients. Vascular endothelial growth factor (VEGF) and CD31 were only examined in tissues of HCC patients mentioned above. The results showed that HOXB13 expression was significantly (P <0.001) higher in HCC (69.4%) than that in surrounding non-tumor tissues (26.4%), positively correlated with tumor VEGF (P <0.001) and microvessel density (MVD) (P = 0.013). Besides, it was associated with tumor capsula (P <0.001), vascular invasion (P <0.001), Edmondson grade (P <0.001), AFP (P = 0.007) and TNM stage (P <0.001). Univariate analysis showed poorer overall survival (OS) rate and disease free survival (DFS) rate in patients expressing higher levels of HOXB13. HOXB13 was also found to be an independent poor prognostic factor of OS and DFS in multivariate analysis. Taken together, our results suggest that increased HOXB13 expression is associated with tumor angiogenesis and progression in HCC and may function as a promising biomarker for unfavorable prognosis of HCC.

HOXB13 contributes to G1/S and G2/M checkpoint controls in prostate

HOXB13 is a homeobox protein that is expressed in normal adult prostate and colon tissues; however, its deregulated expression was evidenced in various malignancies. To characterize the putative role of HOXB13 in cell cycle progression, we performed overexpression and siRNA-mediated knockdown studies in PC-3 and LNCaP cells. Immunohistochemistry (IHC) analyses were also performed using formalin-fixed, paraffin-embedded tissues containing normal, H-PIN and PCa sections from 20 radical prostatectomy specimens. Furthermore, when the role of HOXB13 during cell cycle progression, association with cyclins, cell growth and colony formation using real-time cell proliferation were assessed, we observed that ectopic expression of HOXB13 accumulated cells at G1 through decreasing the cyclin D1 level by promoting its ubiquitination and degradation. This loss slowed S phase entry in both cell lines examined, with an associated decrease in pRb((S780) and (S795)) phosphorylations. Contrary, siRNA-mediated depletion of HOXB13 expression noticeably increased cyclin levels, stabilized E2F1 and CDC25C, subsequent to increased pRb phosphorylations. This increase in Cyclin B1 and CDC25C both together facilitated activation of cyclin B complex via dephosphorylating CDK1((T14Y15)), and resumed the G2/M transition after nocodazole synchronization. Despite an increase in the total expression level and cytoplasmic retention of HOXB13 in H-PIN and PCa samples that were observed via IHC evaluation of prostate tissues, HOXB13 depletion facilitated to an increase in PC-3 and LNCaP cell proliferation. Thus, we suggest that HOXB13 expression is required for cell cycle regulation, and increases by an unknown mechanism consequent to its functional loss in cancer.

Aberrant expression of posterior HOX genes in well differentiated histotypes of thyroid cancers

Molecular etiology of thyroid cancers has been widely studied, and several molecular alterations have been identified mainly associated with follicular and papillary histotypes. However, the molecular bases of the complex pathogenesis of thyroid carcinomas remain poorly understood. HOX genes regulate normal embryonic development, cell differentiation and other critical processes in eukaryotic cell life. Several studies have shown that HOX genes play a role in neoplastic transformation of several human tissues. In particular, the genes belonging to HOX paralogous group 13 seem to hold a relevant role in both tumor development and progression. We have identified a significant prognostic role of HOX D13 in pancreatic cancer and we have recently showed the strong and progressive over-expression of HOX C13 in melanoma metastases and deregulation of HOX B13 expression in bladder cancers. In this study we have investigated, by immunohistochemisty and quantitative Real Time PCR, the HOX paralogous group 13 genes/proteins expression in thyroid cancer evolution and progression, also evaluating its ability to discriminate between main histotypes. Our results showed an aberrant expression, both at gene and protein level, of all members belonging to paralogous group 13 (HOX A13, HOX B13, HOX C13 and HOX D13) in adenoma, papillary and follicular thyroid cancers samples. The data suggest a potential role of HOX paralogous group 13 genes in pathogenesis and differential diagnosis of thyroid cancers.

HOXB13 downregulates intracellular zinc and increases NF-κB signaling to promote prostate cancer metastasis

Characteristically, prostate cancer (PCa) cells exhibit marked decrease in intracellular zinc; however, the mechanism responsible is not clearly understood. HOXB13 is involved in PCa progression and is overexpressed in castration-resistant PCa. DNA microarray analysis of LNCaP Pca cells showed that ZnT zinc output transporters were strikingly upregulated among androgen-independent HOXB13 target genes. Furthermore, exogenous HOXB13 caused intracellular zinc concentrations to fall in PCa cells, stimulated NF-κB-mediated signaling by reducing inhibitor of NF-κB alpha (IκBα) and enhanced the nuclear translocation of RelA/p65. Human prostate tumors also exhibited strong inverse correlation between the protein expressions of HOXB13 and IκBα. Consequently, HOXB13 stimulated PCa cell invasion, and this was inhibited by the suppression of ZnT4. In addition, studies in a PC3 orthotopic mouse model of PCa metastasis showed that HOXB13 is a strong metastatic stimulator. Taken together, these results show that HOXB13 promotes PCa invasion and metastasis by decreasing intracellular zinc levels, thus stimulating NF-κB signals, and suggest that HOXB13 acts as a modulator of intracellular zinc levels that promotes the malignant characteristics of PCa.

HMCan: a method for detecting chromatin modifications in cancer samples using ChIP-seq data

MOTIVATION

Cancer cells are often characterized by epigenetic changes, which include aberrant histone modifications. In particular, local or regional epigenetic silencing is a common mechanism in cancer for silencing expression of tumor suppressor genes. Though several tools have been created to enable detection of histone marks in ChIP-seq data from normal samples, it is unclear whether these tools can be efficiently applied to ChIP-seq data generated from cancer samples. Indeed, cancer genomes are often characterized by frequent copy number alterations: gains and losses of large regions of chromosomal material. Copy number alterations may create a substantial statistical bias in the evaluation of histone mark signal enrichment and result in underdetection of the signal in the regions of loss and overdetection of the signal in the regions of gain.

RESULTS

We present HMCan (Histone modifications in cancer), a tool specially designed to analyze histone modification ChIP-seq data produced from cancer genomes. HMCan corrects for the GC-content and copy number bias and then applies Hidden Markov Models to detect the signal from the corrected data. On simulated data, HMCan outperformed several commonly used tools developed to analyze histone modification data produced from genomes without copy number alterations. HMCan also showed superior results on a ChIP-seq dataset generated for the repressive histone mark H3K27me3 in a bladder cancer cell line. HMCan predictions matched well with experimental data (qPCR validated regions) and included, for example, the previously detected H3K27me3 mark in the promoter of the DLEC1 gene, missed by other tools we tested.

Germline HOXB13 p.Gly84Glu mutation and risk of colorectal cancer

INTRODUCTION

The HOXB13 pGly84Glu mutation has recently been associated with an increased risk of prostate cancer but the association of other cancer sites with this allele has not been assessed. Data has suggested that HOXB13 expression levels are decreased in colorectal cancer (CRC) cell lines indicating this gene may be involved in colorectal tumourigenesis.

METHODS

To evaluate a potential association of this mutation with CRC, we genotyped the mutation in 2695 CRC cases and 4593 controls from population-based registries in Canada and Australia.

RESULTS

The HOXB13 pGly84Glu mutation was more common in CRC cases than controls (0.48% vs. 0.17%, P=0.02) indicating a significant association between the HOXB13 variant and CRC risk (OR=2.8; 95%CI: 1.2-6.8). This association was attenuated but remained significant with the inclusion of previously published and publicly available genotype data. Pedigree analysis of cases and controls revealed that 7/21 HOXB13 mutation carriers had a family history of prostate cancer.

DISCUSSION

This report is the first to suggest a risk of CRC associated with mutations in the HOXB13 gene. These findings require further validation but may be of importance in the screening and genetic counseling of families known to carry the HOXB13 pGly84Glu mutation.