Downregulation of HOXC6 in Serous Ovarian Cancer

HOXC6: A promising biomarker linked to an immunoevasive microenvironment in colorectal cancer based on TCGA analysis and cohort validation

HOXC6 plays an essential part of the carcinogenesis of solid tumors, but its functional relevance within the immune contexture in patients with colorectal cancer (CRC) is still uncertain. We intended to investigate the predictive value of HOXC6 expression for survival outcomes and its correlation with immune contexture in CRC patients by utilizing the Cancer Genome Atlas database (n = 619). Validation was performed in cohorts from Zhongshan Hospital (n = 200) and Shanghai Cancer Center (n = 300). Immunohistochemical (IHC) staining was utilized to compare the levels of immunocytes infiltrating the tumor between the groups with high and low expression of HOXC6. Elevated levels of HOXC6 expression in CRC tissues were linked to malignant progression and poor prognosis. HOXC6 as a risk factor for survival of CRC patients was confirmed. Receiver operating characteristic analysis confirmed its diagnostic value, and a reliable prognostic nomogram was constructed. KEGG analysis and GSEA showed that HOXC6 participated in immune regulation, and its expression was tightly linked to the abundance of infiltrating immunocytes. HOXC6 was upregulated in patients diagnosed with CRC within the two cohorts, and high HOXC6 levels were correlated with a worse prognosis. The high-HOXC6 expression group showed increased infiltration of Treg cells, CD68+ macrophages, CD66b+ neutrophils, and CD8+ T-cells and elevated levels of PD-L1 and PD-1, but decreased levels of granzyme B and perforin. These findings suggest that HOXC6 abundance in patients with CRC determines a poor prognosis, promotes an immunoevasive environment, and directs CD8+ T-cell dysfunction. HOXC6 is expected to become a prospective biomarker for the outcome of CRC.

HomeoboxC6 affects the apoptosis of human vascular endothelial cells and is involved in atherosclerosis

Apoptosis of vascular endothelial cells (VECs) is highly important in the occurrence and development of atherosclerosis (AS). HomeboxC6 (HOXC6) is expressed in higher levels in multiple malignant tissues, and it influences the malignant biological behavior of the cancer cells. However, the effects of HOXC6 on AS and the apoptosis of VECs have not been fully elucidated. In this study, we demonstrated that HOXC6 expression was increased in aortic wall of AS rats and peripheral blood monocytes of patients with coronary heart disease. Furthermore, it was uncovered that BAX expression was upregulated, while BCL-2 expression was downregulated in the aortic wall of AS rats. The apoptosis of human VECs (HVECs) cultured normally or treated with oxidized low-density lipoprotein in vitro was decreased after transfection with HOXC6-siRNA. Moreover, the results of Western blot analysis unveiled that the expressions of proapoptotic proteins, such as BAX, caspase-3, cleaved-caspase-3, and caspase-9 were reduced, while the expression of antiapoptotic protein, BCL-2, was elevated. Meanwhile, mRNA and protein expressions of phospholipase C beta (PLCβ) were decreased, the phosphorylation levels of protein kinase C zeta (PKCζ) and nuclear transcription factor-κB-p65 (NF-κBp65) and the membrane translocation of PKCζ were reduced as well. Besides, the expression of interleukin-18 (IL-18) protein was downregulated. However, after overexpression of HOXC6, the opposite trends of the abovementioned indices were observed. Furthermore, the inhibition of apoptosis induced by HOXC6-siRNA was reversed by lysophosphatidylcholine, an activator of PKCζ. Taken together, our results indicated that HOXC6 can promote the apoptosis of HVECs and may be involved in the occurrence and development of AS, which may be partially associated with the activation of PLCβ/PKCζ/NF-κBp65/IL-18 signaling pathway.

The distribution of some homeobox proteins in the bovine placenta during gestation

Homeobox proteins are transcription factors known to be involved in the molecular basics of body model formation and transformation. Some homeobox proteins are known to play critical roles in the control of the extraembryonic development of the placenta during gestation and in the regulation of uterine and placental physiology in adults. The gravid uteruses and placentas of 27 Holsteins cows, obtained from private slaughterhouses, were used in this study. The tissues were assigned to three groups as belonging to the first, second and third timesters of gestation, based on the fetal ages determined. Subsequently, the tissues were subjected to immunohistochemical staining using antibodies specific to the proteins investigated in the study. The evaluation of the immunohistochemical findings obtained in this study, demonstrated the presence of trimester-dependent varying intensities of immunoreactions in the uterus and placenta. Immunoreactivity was observed particularly in the luminal and glandular epithelial cells of the uterus, as well as in stromal and some endothelial cells. Furthermore, immunoreactivity for the proteins HOXA10, HOXB6, HOXC6 and Dlx-5 was determined in the smooth muscle cells. Moreover, immunoreactivity was also detected in the maternal epithelium and fetal trophoblasts found in the structure of the placenta. The results suggest that the homeobox proteins investigated may have critical roles in the regulation of endometrial functions in cows, and the proliferation and differentiation of endometrial and placental cells. It is concluded that these proteins may have physiological roles in the formation and development of the placenta, as well as in the maintenance of pregnancy.

HOXC9 overexpression is associated with gastric cancer progression and a prognostic marker for poor survival in gastric cancer patients

BACKGROUND

As a member of the homeobox family, HOXC9 is overexpressed in several malignant tumors and may be regarded as a biomarker for prognostic evaluation. However, the expression pattern and prognostic significance of HOXC9 in gastric cancer have not been detailedly studied.

METHODS

HOXC9 mRNA expression difference in normal tissues and gastric cancer tissues were investigated using RT-PCR, and immunohistochemistry was used to analyze HOXC9 protein expression in precancerous lesions and gastric cancer at different stages, and its clinicopathological characteristics and survival were statistically tested.

RESULTS

Compared to the normal gastric mucosa tissues, the expression levels of HOXC9 mRNA in the human gastric cancer tissues were significantly higher. HOXC9 protein levels of gastric cancer were obviously higher than that in other noncancerous tissues (P < 0.001). Positive expression of HOXC9 was associated with tumor size (P = 0.036), lymphatic invasion (P = 0.001), depth of invasion (P < 0.001), lymph-node metastasis (P < 0.001), and higher stage disease (P < 0.001). Furthermore, Kaplan-Meier survival curves showed that HOXC9 expression is inversely correlated with both disease-specific and disease-free 5 year survival of patients with gastric cancer (P < 0.001 for both). Strikingly, our multivariate Cox regression analysis revealed that HOXC9 expression was an independent poor prognostic factor in gastric cancer (P < 0.05).

CONCLUSIONS

HOXC9 expression was observed in a subset of patients with gastric cancer and was associated with an unfavorable prognosis. As well as being a new prognostic indicator, HOXC9 protein could be a useful marker for early diagnosis.

HOXC6 in the prognosis of prostate cancer

Aims: Our study aimed to investigate the expression and prognostic role of homeobox C6 (HOXC6) in prostate cancer (PCa). Methods: Relative expression of HOXC6 at mRNA and protein levels in tissues and cell lines of PCa were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis, respectively. Association between HOXC6 expression and clinical factors was analyzed by Chi-square test. HOXC6 effects on the proliferation, invasion and metastasis of PCa cells were severally examined through CCK-8 and transwell assays. Results: Relative expressions of HOXC6 at mRNA and protein levels were obviously higher in both PCa tissues and cells than in adjacent non-cancerous tissues and normal human prostate epithelial cells (p < .05). Chi-square test demonstrated that high expression of HOXC6 was significantly associated with PSA concentration, Gleason score and TNM stage (p < .05). The down-regulation of HOCX6 remarkably inhibited the proliferation, migration and invasion of PCa cells. Kaplan-Meier analysis showed that patients with high HOXC6 expression had shorter overall survival than those with low HOXC6 expression (log rank test, p < .001). Conclusion: Up-regulated HOXC6, in PCa patients, could not only participate in the progression of PCa but also function as an independent prognostic marker for the cancer.

Overexpression of HOXC6 promotes cell proliferation and migration via MAPK signaling and predicts a poor prognosis in glioblastoma

Background

Homeobox (HOX) genes encode transcription factors that are critical to morphogenesis and cell differentiation. Although the dysregulation of several HOX genes in glioblastoma (GBM) has been reported, little is known about HOXC6 expression in GBM. Therefore, in this study, we investigated the expression levels of the HOXC6 in GBM and explored the regulatory mechanism underlying the role of HOXC6 in GBM progression.

Methods

The ONCOMINE and Oncolnc databases were used to predict the expression level of HOXC6 mRNA and its prognostic value in GBM. The expressions of HOXC6 mRNA in GBM tissues and adjacent brain tissues were detected using qRT-PCR and Western blot. Immunohistochemistry was performed to verify the HOXC6 protein expression in 107 GBM tissues. Kaplan–Meier and Cox analyses were performed to validate the correlation between HOXC6 expression and GBM prognosis. Lentivirus-mediated HOXC6 mRNA overexpression and interference system were established and transfected into U251 and U87 cell lines. CCK-8, colony formation, wound healing and transwell assay were utilized to evaluate the effects of HOXC6 on proliferation and migration of human GBM cells.

Results

High expression of HOXC6 was observed in GBM tissues and GBM cells lines, and it correlated with a decreased overall survival and disease-free survival. Overexpression of HOXC6 promoted the GBM cell proliferation and migration, whereas depletion of HOXC6 reduced GBM cell proliferation and migration. Mechanistic study showed that upregulation of HOXC6 significantly increased the phosphorylation of Jun amino-terminal kinase, ERK and P38, as well as the expression of mitogen-activated protein kinase (MAPK) signaling–related genes, including c-myc, c-jun and p53. Inversely, silencing HOXC6 showed the opposite results.

Conclusion

HOXC6 promoted proliferation and migration of GBM cells via the activation of MAPK pathway.

HOX Genes in High Grade Ovarian Cancer

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

HOXC6 promotes migration, invasion and proliferation of esophageal squamous cell carcinoma cells via modulating expression of genes involved in malignant phenotypes

Background

HOXC6 is a member of the HOX gene family. The elevated expression of this gene occurs in prostate and breast cancers. However, the role of HOXC6 in esophageal squamous cell carcinoma (ESCC) remains largely uninvestigated.

Methods

The expression of HOXC6 was examined by immunohistochemistry, quantitative real-time PCR and immunoblotting assays. The lentivirus-mediated expression of HOXC6 was verified at mRNA and protein levels. Wound healing and Matrigel assays were performed to assess the effect of HOXC6 on the migration and invasion of cancer cells. The growth curving, CCK8, and colony formation assays were utilized to access the proliferation capacities. RNA-seq was performed to evaluate the downstream targets of HOXC6. Bioinformatic tool was used to analyze the gene expression.

Results

HOXC6 was highly expressed in ESCC tissues. HOXC6 overexpression promoted the migration, invasion, and proliferation of both Eca109 and TE10 cells. There were 2,155 up-regulated and 759 down-regulated genes in Eca109-HOXC6 cells and 95 up-regulated and 47 down-regulated genes in TE10-HOXC6 cells compared with the results of control. Interestingly, there were only 20 common genes, including 17 up-regulated and three down-regulated genes with similar changes upon HOXC6 transfection in both cell lines. HOXC6 activated several crucial genes implicated in the malignant phenotype of cancer cells.

Discussion

HOXC6 is highly expressed in ESCC and promotes malignant phenotype of ESCC cells. HOXC6 can be used as a new therapeutic target of ESCC.

Potential role of the HOXD8 transcription factor in cisplatin resistance and tumour metastasis in advanced epithelial ovarian cancer

Few studies have examined the potential transcription factor (TF) simultaneously associated with cisplatin resistance and metastasis in ovarian cancer. To assess a related mechanism, a 345-channel protein/DNA array and transcriptional activity ELISA were performed to compare the TF activities in the cisplatin-sensitive SKOV3 and cisplatin-resistant SKOV3-DDP cells and in HO-8910 and the homologous highly metastatic HO-8910PM cells. In SKOV3-DDP vs. SKOV3 cells, 43 TFs were up-regulated, while 31 were down-regulated. In HO-8910PM vs. HO-8910 cells, 13 TFs were up-regulated, while 18 were down-regulated. In these two models, 4 TFs (HOXD8(1), HOXD8(2), RB, RFX1/2/3) were simultaneously up-regulated, and 9 TFs (SRE, FKHR, Angiotensinogen ANG-IRE, Pax2, CD28RC/NF-IL2B, HLF, CPE, CBFB and c-Ets-1) were down-regulated. HOXD8 mRNA and protein expression levels measured by reverse transcription polymerase chain reaction and ELISA, respectively, were significantly higher in SKOV3-DDP and HO-8910PM than in their corresponding cell lines (both p < 0.05). In 52 cases of different ovarian disease, the patients with recurrent and cisplatin-resistant ovarian cancer had higher expression levels of HOXD8 than patients with primary malignant tumours (p = 0.018, p = 0.001) or benign tumours (p = 0.001, p < 0.001). Taken together, these results suggest that HOXD8 is potentially associated with both cisplatin resistance and metastasis in advanced ovarian cancer.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Dysregulation of AKT3 along with a small panel of mRNAs stratifies high-grade serous ovarian cancer from both normal epithelia and benign tumor tissues

Screening methods of High-Grade Serous Ovarian Cancer (HGSOC) lack specificity and sensitivity, partly due to benign tumors producing false-positive findings. We utilized a differential expression analysis pipeline on malignant tumor (MT) and normal epithelial (NE) samples, and also filtered the results to discriminate between MT and benign tumor (BT). We report that a panel of 26 dysregulated genes stratifies MT from both BT and NE. We further validated our findings by utilizing unsupervised clustering methods on two independent datasets. We show that the 26-genes panel completely distinguishes HGSOC from NE, and produces a more accurate classification between HGSOC and BT. Pathway analysis reveals that AKT3 is of particular significance, because of its high fold change and appearance in the majority of the dysregulated pathways. mRNA patterns of AKT3 suggest essential connections with tumor growth and metastasis, as well as a strong biomarker potential when used with 3 other genes (PTTG1, MND1, CENPF). Our results show that dysregulation of the 26-mRNA signature panel provides an evidence of malignancy and contribute to the design of a high specificity biomarker panel for detection of HGSOC, potentially in an early more curable stage.

Dysregulated expression of homeobox family genes may influence survival outcomes of patients with epithelial ovarian cancer: analysis of data from The Cancer Genome Atlas

Homeobox (HOX) family genes encode key transcription factors for embryogenesis and may be correlated with carcinogenesis. The aim of this study was to elucidate whether aberrant expression of HOX genes influences outcomes in epithelial ovarian cancer (EOC). Gene expression data and clinicopathologic information from 630 patients with EOC were downloaded from The Cancer Genome Atlas database. We explored correlations between expression levels of HOX gene family members and clinicopathological variables. Higher expression of HOXA1, A4, A5, A7, A10, A11, B13, C13, D1, and D3 was associated with advanced FIGO stage. Suboptimal residual disease after debulking surgery was significantly correlated with higher expression of HOXB9, B13, and C13. Additionally, patients with high expression of HOXC6 and C11 were significantly more likely to have poor performance status. Overall survival was significantly shorter in patients with high, rather than low, expression of two HOX genes (HOXA10 and B3), and significantly longer in patients with high rather than low HOXC5 expression. Dysregulated expression of the HOXA10, B3, and C5 was significantly correlated with overall survival in EOC patients. HOX gene expression levels are potentially useful as a prognostic indicator in EOC, and HOX genes may represent a novel and promising target for anticancer therapeutics.

Homeobox C9 suppresses Beclin1-mediated autophagy in glioblastoma by directly inhibiting the transcription of death-associated protein kinase 1

BACKGROUND

The transcription factor homeobox C9 (HOXC9) plays a crucial role in developmental regulatory systems, where it determines the specific positional identities of cells along the anteroposterior axis. The expression of HOXC9 has been found to be dysregulated in some cancers such as lung cancer, breast cancer, and neuroblastoma. Here, we report for the first time that HOXC9 is a novel autophagy regulator and reveal its oncogenic role in cell survival and its usefulness as a prognostic marker in glioblastoma patients.

METHODS

Kaplan-Meier analysis was performed to evaluate the possible prognostic value of HOXC9 in glioblastoma. Growth curve assays, subcutaneous, and orthotopic implantations were used to analyze cell viability and tumor formation, respectively. Luciferase and chromatin immunoprecipitation assays were employed to explore the mechanisms involved in the association between HOXC9 and its downstream effector, death-associated protein kinase 1 (DAPK1).

RESULTS

High expression of HOXC9 was found to be an indicator of a poor prognosis in glioblastoma. HOXC9 knockdown resulted in a significant reduction of cell viability, migration, invasion, and tumorigenicity and a marked increase in autophagy. During the autophagy process, HOXC9 inhibited DAPK1 transcription by directly binding to its promoter. The downregulation of HOXC9 releases its transcriptional inhibition of DAPK1, resulting in the activation of the DAPK1-Beclin1 pathway, which induces autophagy in glioblastoma cells.

CONCLUSIONS

Collectively, our data indicate that HOXC9 is an oncogene in glioblastoma. We have revealed its role in the control of autophagy, and we suggest that HOXC9 is a novel and promising therapeutic target.