HOXA10 expression in endometrial adenocarcinoma

Long Noncoding RNA HOXB-AS1 Is Upregulated in Endometrial Carcinoma and Sponged miR-149-3p to Upregulate Wnt10b

The functions of Long noncoding RNA (lncRNA) HOXB-AS1 have been investigated in glioblastoma and multiple myeloma. However, the role of lncRNA HOXB-AS1 in endometrial carcinoma (EC) remains largely unknown. This study investigated the underlying mechanisms of the lncRNA HOXB-AS1 on the progression of EC. In this study, We found that HOXB-AS1 expression was significantly upregulated in EC tissue samples and was associated with shorter survival time. Furthermore, upregulation of HOXB-AS1 promoted proliferation, invasion, and migration of EC cell. HOXB-AS1 and Wnt10b directly bound to miR-149-3p. HOXB-AS1 increased the expression of Wnt10b by binding to miR-149-3p. We further verified the upregulation of β-catenin, cyclin D1, and c-myc induced by HOXB-AS1. In conclusion, our results indicated that HOXB-AS1 exerted oncogenic function as competing endogenous RNA (ceRNA) of miR-149-3p to release Wnt10b and activated Wnt/β-catenin pathway.

PTEN loss and HOXA10 expression are associated with ovarian endometrioid adenocarcinoma differentiation and progression

Epithelial ovarian cancer is a heterogeneous disease that is subdivided into five major histotypes but the mechanisms driving their differentiation are not clear. Mutations in adenomatous polyposis coli (APC) and β-catenin are commonly observed in the human ovarian endometrioid adenocarcinoma (OEA) patients. However, the mechanisms subsequent to APC deletion in ovarian tumorigenesis have not been well characterized. We have conditionally deleted APC in the murine ovarian surface epithelium (OSE) and showed that its loss leads to development of epithelial inclusion cysts. High-grade OEAs with tightly packed villoglandular histology were observed in older APC-deleted mice. Phosphatase and tensin homolog (PTEN) expression was elevated in the early lesions but lost after progression to the more advanced tumors. Knockdown of APC or expression of a gain-of-function β-catenin similarly induced human OSE cells to develop tumors with endometrioid histology in xenografts. Expression of HOXA10 was induced in both the advanced APC-deleted murine tumors and in the tumor xenografts of human OSE cells with knocked-down APC. These results show that reduced APC activity is sufficient to induce formation of epithelial inclusion cysts and support OEA development and suggest that induced HOXA10 expression and loss of PTEN are key mechanisms driving endometrioid histotype differentiation and progression.

Homeodomain-containing protein HOXB9 regulates expression of growth and angiogenic factors, facilitates tumor growth in vitro and is overexpressed in breast cancer tissue

HOXB9 is a homeobox-containing gene and is critical for the development of mammary gland and sternum. HOXB9 is also regulated by estrogen and is critical for angiogenesis. We investigated the biochemical roles of HOXB9 and its homeodomain in cell-cycle progression and tumorigenesis. Our studies demonstrated that HOXB9 is overexpressed in breast cancer tissue. HOXB9 overexpression stimulated 3D formation in soft agar assay. HOXB9 binds to the promoters of various tumor growth and angiogenic factors and regulates their expression. The homeodomain of HOXB9 plays crucial roles in transcriptional regulation of tumor growth factors and also in 3D colony formation, indicating crucial roles of the HOXB9 homeodomain in tumorigenesis. Overall, we demonstrated that HOXB9 is a critical regulator of tumor growth factors and is associated with tumorigenesis.

miRNA-135a promotes breast cancer cell migration and invasion by targeting HOXA10

Background

miRNAs are a group of small RNA molecules regulating target genes by inducing mRNA degradation or translational repression. Aberrant expression of miRNAs correlates with various cancers. Although miR-135a has been implicated in several other cancers, its role in breast cancer is unknown. HOXA10 however, is associated with multiple cancer types and was recently shown to induce p53 expression in breast cancer cells and reduce their invasive ability. Because HOXA10 is a confirmed miR-135a target in more than one tissue, we examined miR-135a levels in relation to breast cancer phenotypes to determine if miR-135a plays role in this cancer type.

Methods

Expression levels of miR-135a in tissues and cells were determined by poly (A)-RT PCR. The effect of miR-135a on proliferation was evaluated by CCK8 assay, cell migration and invasion were evaluated by transwell migration and invasion assays, and target protein expression was determined by western blotting. GFP and luciferase reporter plasmids were constructed to confirm the action of miR-135a on downstream target genes including HOXA10. Results are reported as means ± S.D. and differences were tested for significance using 2-sided Student"s t-test.

Results

Here we report that miR-135a was highly expressed in metastatic breast tumors. We found that the expression of miR-135a was required for the migration and invasion of breast cancer cells, but not their proliferation. HOXA10, which encodes a transcription factor required for embryonic development and is a metastasis suppressor in breast cancer, was shown to be a direct target of miR-135a in breast cancer cells. Our analysis showed that miR-135a suppressed the expression of HOXA10 both at the mRNA and protein level, and its ability to promote cellular migration and invasion was partially reversed by overexpression of HOXA10.

Conclusions

In summary, our results indicate that miR-135a is an onco-miRNA that can promote breast cancer cell migration and invasion. HOXA10 is a target gene for miR-135a in breast cancer cells and overexpression of HOXA10 can partially reverse the miR-135a invasive phenotype.

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.

HOXC10 is overexpressed in breast cancer and transcriptionally regulated by estrogen via involvement of histone methylases MLL3 and MLL4

HOXC10 is a critical player in the development of spinal cord, formation of neurons, and associated with human leukemia. We found that HOXC10 is overexpressed in breast cancer and transcriptionally regulated by estrogen (17β-estradiol, E(2)). The HOXC10 promoter contains several estrogen response elements (ERE1-7, half-sites). A luciferase-based reporter assay showed that ERE1 and ERE6 of HOXC10 promoter are E(2) responsive. ERα and ERβ play critical roles in E(2)-mediated activation of HOXC10. Knockdown of ERα and ERβ downregulated E(2)-induced HOXC10 expression. ERα and ERβ bind to ERE1 and ERE6 regions in an E(2)-dependent manner. Additionally, knockdown of histone methylases MLL3 and MLL4 (but not MLL1 and MLL2) diminished E(2)-induced expression of HOXC10. MLL3 and MLL4 were bound to the ERE1 and ERE6 regions of HOXC10 promoter in an E(2)-dependent manner. Overall, we demonstrated that HOXC10 is overexpressed in breast cancer, and it is an E(2)-responsive gene. Histone methylases MLL3 and MLL4, along with ERs, regulate HOXC10 gene expression in the presence of E(2).

Expression of HOXA10 in endometrial hyperplasia and adenocarcinoma and regulation by sex hormones in vitro

OBJECTIVE

The objective of the study was to determine the expression of HOXA10 in human endometrial tissue in endometrial hyperplasia and carcinomas, and regulation by sex steroids in Ishikawa cells.

METHODS

Endometrial tissue was obtained from 133 subjects with normal endometria, endometrial hyperplasia, or endometrial adenocarcinoma. Among 133 specimens, 20 were normal endometria, 19 were simple hyperplasias without atypia, 20 were complex hyperplasias without atypia, 33 were atypical hyperplasias, and 41 were endometrial adenocarcinomas. The expression of HOXA10 was analyzed by immunohistochemistry. Ishikawa cell lines were incubated with 17β estradiol (10⁻⁸ mol/L) alone, medroxyprogesterone acetate (10⁻⁶ mol/L) alone, or the combination of estrogen and progesterone for 48 hours, respectively. In certain experiments, the antiprogestin antagonist, RU486 (10⁻⁵ mol/L), was also added to Ishikawa cells along with estradiol and medroxyprogesterone acetate for 48 hours. The expression of HOXA10 gene was detected by reverse transcriptase-polymerase chain reaction and Western blotting.

RESULTS

HOXA10 was expressed in both normal and neoplastic endometria. No significant difference in HOXA10 expression was found between normal and hyperplastic endometrial tissues. The expression of HOXA10 was decreased in endometrial adenocarcinomas compared with normal endometria. Estrogen alone, progestin alone, or progestin combined with estrogen could significantly increase the expression of HOXA10 gene (P<0.05). RU486 could inhibit the effect of up-regulation of HOXA10 expression by progestin.

CONCLUSIONS

The expression of HOXA10 was deregulated in endometrial carcinomas and up-regulated by sex hormones.

HOXC6 Is transcriptionally regulated via coordination of MLL histone methylase and estrogen receptor in an estrogen environment

Homeobox (HOX)-containing gene HOXC6 is a critical player in mammary gland development and milk production, and is overexpressed in breast and prostate cancers. We demonstrated that HOXC6 is transcriptionally regulated by estrogen (E2). HOXC6 promoter contains two putative estrogen response elements (EREs), termed as ERE1(1/2) and ERE2(1/2). Promoter analysis using luciferase-based reporter assay demonstrated that both EREs are responsive to E2, with ERE1(1/2) being more responsive than ERE2(1/2). Estrogen receptors (ERs) ERα and ERβ bind to these EREs in an E2-dependent manner, and antisense-mediated knockdown of ERs suppressed the E2-dependent activation of HOXC6 expression. Similarly, knockdown of histone methylases MLL2 and MLL3 decreased the E2-mediated activation of HOXC6. However, depletion of MLL1 or MLL4 showed no significant effect. MLL2 and MLL3 were bound to the HOXC6 EREs in an E2-dependent manner. In contrast, MLL1 and MLL4 that were bound to the HOXC6 promoter in the absence of E2 decreased upon exposure to E2. MLL2 and MLL3 play key roles in histone H3 lysine-4 trimethylation and in the recruitment of general transcription factors and RNA polymerase II in the HOXC6 promoter during E2-dependent transactivation. Nuclear receptor corepressors N-CoR and SAFB1 were bound in the HOXC6 promoter in the absence of E2, and that binding was decreased upon E2 treatment, indicating their critical roles in suppressing HOXC6 gene expression under nonactivated conditions. Knockdown of either ERα or ERβ abolished E2-dependent recruitment of MLL2 and MLL3 into the HOXC6 promoter, demonstrating key roles of ERs in the recruitment of these mixed lineage leukemias into the HOXC6 promoter. Overall, our studies demonstrated that HOXC6 is an E2-responsive gene, and that histone methylases MLL2 and MLL3, in coordination with ERα and ERβ, transcriptionally regulate HOXC6 in an E2-dependent manner.

Cigarette smoke increases progesterone receptor and homeobox A10 expression in human endometrium and endometrial cells: a potential role in the decreased prevalence of endometrial pathology in smokers

Cigarette smoking has long been tied to a multitude of poor health outcomes; however, in reproductive biology, smoking has shown several unintuitive findings. Smoking is associated with significantly decreased rates of endometriosis and endometrial cancer. Here, we show that treatment with cigarette smoke extract leads to increased mRNA and protein expression of homeobox A10 (HOXA10) and progesterone receptor (PGR) as well as more rapid decidualization of endometrial stromal cells in vitro. In vivo, mice exposed to cigarette smoke similarly showed increased expression of HOXA10 and PGR in the endometrium. Both HOXA10 and PGR drive endometrial differentiation and are suppressed in endometrial tumors and in endometriosis. The increased expression found upon exposure to cigarette smoke may provide a protective effect, mediating the decreased incidence of endometrial disease among smokers. This mechanism contrasts with the accepted paradigm that the effects of smoking on the uterus are secondary to ovarian alterations rather than direct effects on endometrium as demonstrated here.

Expression pattern of the class I homeobox genes in ovarian carcinoma

OBJECTIVE

Although some sporadic reports reveal the link between the homeobox (HOX) genes and ovarian carcinoma, there is no comprehensive analysis of the expression pattern of the class I homeobox genes in ovarian carcinoma that determines the candidate genes involved in ovarian carcinogenesis.

METHODS

The different patterns of expression of 36 HOX genes were analyzed, including 4 ovarian cancer cell lines and 4 normal ovarian tissues. Using a reverse transcription-polymerase chain reaction (RT-PCR) and quantification analysis, the specific gene that showed a significantly higher expression in ovarian cancer cell lines than in normal ovaries was selected, and western blot analysis was performed adding 7 ovarian cancer tissue specimens. Finally, immunohistochemical and immunocytochemical analyses were performed to compare the pattern of expression of the specific HOX gene between ovarian cancer tissue and normal ovaries.

RESULTS

Among 36 genes, 11 genes had a different level of mRNA expression between the cancer cell lines and the normal ovarian tissues. Of the 11 genes, only HOXB4 had a significantly higher level of expression in ovarian cancer cell lines than in normal ovaries (p=0.029). Based on western blot, immunohistochemical, and immunocytochemical analyses, HOXB4 was expressed exclusively in the ovarian cancer cell lines or cancer tissue specimens, but not in the normal ovaries.

CONCLUSION

We suggest HOXB4 may be a novel candidate gene involved in ovarian carcinogenesis.

Differential expression of genes from the homeobox A cluster in deep endometriotic nodules and peritoneal lesions

OBJECTIVE

To compare expression of homeobox A (HOXA) genes involved in the differentiation of the female reproductive tract in deep endometriotic nodules and peritoneal lesions.

DESIGN

Prospective experimental study.

SETTING

Academic gynecology research unit.

PATIENT(S)

Thirty patients undergoing laparoscopy.

INTERVENTION(S)

During laparoscopy, deep endometriotic nodules (n=30) and peritoneal lesions (n=11) were recovered. Eutopic endometrium and vaginal tissue (n=30) were collected for control purposes.

MAIN OUTCOME MEASURE(S)

Quantification of HOXA-9, HOXA-10, HOXA-11, and HOXA-13 in deep nodules, peritoneal lesions, and control samples by real-time reverse-transcription polymerase chain reaction, and localization of HOXA-10 and HOXA-13 proteins by immunohistochemistry.

RESULT(S)

The HOXA-13 transcripts were detected in 29 out of 30 nodules, and their expression was significantly higher than in vaginal tissue, but they were barely detectable in endometrium and peritoneal lesions. Expression of HOXA-10 and HOXA-11 transcripts in deep nodules was similar to eutopic endometrium, and HOXA-10 expression was significantly lower in peritoneal endometriotic lesions. The HOXA-10 immunostaining was mainly localized in the stroma of deep endometriotic nodules, HOXA-13 in glandular structures and stroma, and neither of these proteins were detected in fibromuscular areas.

CONCLUSION(S)

Marked expression of HOXA-10 and HOXA-13 in the endometrium-like tissue of nodules but low expression in peritoneal endometriotic lesions supports the theory of differential origin of these two types of endometriosis.

Global analysis of genes regulated by HOXA10 in decidualization reveals a role in cell proliferation

Homeobox (HOX) A10 is essential for fertility as demonstrated in transgenic mice, specifically affecting implantation and decidualization. Its role in human decidualization, however, remains unknown. In this study, we used gene silencing followed by microarray analysis to decipher the role of HOXA10 during decidualization of human endometrial stromal cells (HESCs). HOXA10 was knocked down using siRNA oligonucleotide transfection and cells were treated with estradiol, medroxyprogesterone acetate and dibutyryl cAMP (H + cAMP) to induce decidualization. Genes significantly regulated were identified using the Affymetrix microarray chip. With this method, 2361 transcripts were significantly altered by 1.5-fold or higher (P < 0.05) with H + cAMP treatment only. Of these genes, 258 were significantly up-regulated by HOXA10 knockdown and 236 transcripts were significantly down-regulated by more than 1.5-fold, totaling 494 genes that were regulated by HOXA10 during decidualization. Data analysis using the Ingenuity System revealed that many of the genes regulated by HOXA10 knockdown during H + cAMP treatment were associated with cell cycle. Real-time PCR was used to confirm that HOXA10 knockdown decreased expression of the cell cycle genes CDC2 and CCNB2. In addition, a higher percentage of cells were arrested in the G2/M phase. Next, we observed that cell proliferation as measured by BrdU incorporation was decreased upon HOXA10 knockdown and H + cAMP treatment. Apoptosis, on the other hand, as measured by Annexin V staining was not influenced by siHOXA10 in decidualizing cells. Together, these data demonstrate that during decidualization of HESC, HOXA10 is actively involved in promoting cell proliferation through the regulation of hundreds of genes.

Smoking and cancer-related gene expression in bronchial epithelium and non-small-cell lung cancers

Tobacco smoking is the leading cause of lung cancer worldwide. Gene expression in surgically resected and microdissected samples of non-small-cell lung cancers (18 squamous cell carcinomas and nine adenocarcinomas), matched normal bronchial epithelium, and peripheral lung tissue from both smokers (n = 22) and non-smokers (n = 5) was studied using the Affymetrix U133A array. A subset of 15 differentially regulated genes was validated by real-time PCR or immunohistochemistry. Hierarchical cluster analysis clearly distinguished between benign and malignant tissue and between squamous cell carcinomas and adenocarcinomas. The bronchial epithelium and adenocarcinomas could be divided into the two subgroups of smokers and non-smokers. By comparison of the gene expression profiles in the bronchial epithelium of non-smokers, smokers, and matched cancer tissues, it was possible to identify a signature of 23 differentially expressed genes, which might reflect early cigarette smoke-induced and cancer-relevant molecular lesions in the central bronchial epithelium of smokers. Ten of these genes are involved in xenobiotic metabolism and redox stress (eg AKR1B10, AKR1C1, and MT1K). One gene is a tumour suppressor gene (HLF); two genes act as oncogenes (FGFR3 and LMO3); two genes are involved in matrix degradation (MMP12 and PTHLH); three genes are related to cell differentiation (SPRR1B, RTN1, and MUC7); and five genes have not been well characterized to date. By comparison of the tobacco-exposed peripheral alveolar lung tissue of smokers with non-smokers and with adenocarcinomas from smokers, it was possible to identify a signature of 27 other differentially expressed genes. These genes are involved in the metabolism of xenobiotics (eg GPX2 and FMO3) and may represent cigarette smoke-induced, cancer-related molecular targets that may be utilized to identify smokers with increased risk for lung cancer.

Neonatal estrogenic exposure suppresses PTEN-related endometrial carcinogenesis in recombinant mice

Human endometrial carcinomas, as well as complex atypical hyperplasias (CAH), are estrogen related and frequently have mutations in the PTEN gene. However, the mutual contribution of estrogen and PTEN mutations to endometrial carcinogenesis in vivo is unknown. To address this issue, we investigated whether neonatal estrogenic treatments augment the incidence of CAH and carcinomas in murine PTEN (mPTEN) heterozygous (+/-) mutant mice, an animal model for endometrial carcinoma. Low doses of diethylstilbestrol (1 ng/g/day), genistein (50 microg/g/day) in phytoestrogens, estriol (E(3)) (4 microg/g/day), and vehicle (ethanol and corn oil) were administered subcutaneously daily to neonatal pups from the 1st to 5th day after birth. At 52 weeks of age, the morphological changes in the endometrium, and uterine expression of Hoxa 10 and Hoxa 11, were evaluated. These Hoxa genes are abdominal B-type homeobox genes, which normally regulate differentiation of the Müllerian duct. The incidence of CAH and adenocarcinomas of the endometrium was significantly decreased by the neonatal estrogenic treatments in the mPTEN+/- mice. Coincidentally, all treatments significantly decreased the stromal cell density, and CAH and adenocarcinomas rarely developed in the epithelium adjacent to the affected endometrial stroma. Moreover, the uterine expression of Hoxa 10 in mice with neonatal genistein and E(3) treatments, and that of Hoxa 11 in mice with all treatments, was significantly lower when compared with vehicle alone. Taken together, neonatal estrogenic exposure induced stromal atrophy and/or hyalinization accompanied by repressed expression of Hoxa 10 and Hoxa 11, and exerted an inhibitory effect on PTEN-related tumorigenesis. These findings provide new insight into the interaction between endometrial epithelium and stroma in endometrial carcinogenesis in vivo.

Deregulation of the HOXA10 homeobox gene in endometrial carcinoma: role in epithelial-mesenchymal transition

Homeobox genes encode transcription factors that control cell differentiation and play essential roles in developmental patterning. Increasing evidence indicates that many homeobox genes are aberrantly expressed in cancers, and that their deregulation significantly contributes to tumor progression. The homeobox gene HOXA10 controls uterine organogenesis during embryonic development and functional endometrial differentiation in the adult. We investigated whether HOXA10 expression is deregulated in endometrial carcinomas, and how counteracting this aberrant expression modifies tumor behavior. We found that down-regulation of HOXA10 expression in endometrial carcinomas strongly correlates with increased tumor grade and is associated with methylation of the HOXA10 promoter. Enforced expression of HOXA10 in endometrial carcinoma cells inhibited invasive behavior in vitro and tumor dissemination in nude mice. The inhibitory effect of HOXA10 on invasive behavior was attributable at least in part to the ability of HOXA10 to induce expression of the epithelial cell adhesion molecule E-cadherin by down-regulating expression of Snail, a repressor of E-cadherin gene transcription. These findings reveal a novel role for HOXA10 deregulation in the progression of endometrial carcinoma by promoting epithelial-mesenchymal transition.