Knock-Down of HOXB8 Prohibits Proliferation and Migration of Colorectal Cancer Cells via Wnt/β-Catenin Signaling Pathway

Downregulation of homeobox B8 in attenuating non-small cell lung cancer cell migration and invasion though the epithelial-mesenchymal transition pathway

Background

Homeobox (HOX) family genes have been identified as regulators of cancer development. No research exists concerning the mechanisms underlying homeobox B8 (HOXB8) activity in non-small cell lung cancer (NSCLC). In this study, we investigated expression and biological function in NSCLC to determine whether it is an important marker of patient prognosis.

Methods

HOXB8 expression in NSCLC tissues was investigated using immunohistochemistry (IHC) and Western blot assays. In addition, HOXB8 was knocked down in NSCLC cells to assess its biological functions in this context. The invasive and migratory potential of cells was evaluated by using Transwell (BD, Franklin Lakes, NJ, USA) inserts with 8-µm pores. Furthermore, Western blotting was used to explore whether HOXB8 can influence epithelial-mesenchymal transition (EMT).

Results

HOXB8 was expressed at high levels in NSCLC tissues and cell lines compared with adjacent normal tissues. Patients with high HOXB8 expression had shorter survival time and worse prognosis. HOXB8 expression was associated with pathological grading, tumor size, and lymph node metastasis. HOXB8 was prognostic in patients with NSCLC. After knockdown of HOXB8 via small interfering RNA, the proliferation, migration and invasion ability of the cells were significantly reduced compared with the control group. Moreover, EMT was inhibited by the downregulation of HOXB8 expression, as the expressions of E-cadherin was upregulated and that of the N-cadherin, vimentin, matrix metalloproteinase 2 (MMP2), and twist were downregulated. HOXB8 is a member of the ANTP homeobox family and encodes a nuclear protein with a homeobox DNA-binding domain. It is included in a cluster of homeobox B genes located on chromosome 17. The encoded protein functions as a sequence-specific transcription factor that is involved in development.

Conclusions

HOXB8 is highly expressed in NSCLC and may predict prognosis of patients with this type of cancer. Furthermore, HOXB8 may promote NSCLC progression through the regulation of the EMT process.

Modular and mechanistic changes across stages of colorectal cancer

BACKGROUND

While mechanisms contributing to the progression and metastasis of colorectal cancer (CRC) are well studied, cancer stage-specific mechanisms have been less comprehensively explored. This is the focus of this manuscript.

METHODS

Using previously published data for CRC (Gene Expression Omnibus ID GSE21510), we identified differentially expressed genes (DEGs) across four stages of the disease. We then generated unweighted and weighted correlation networks for each of the stages. Communities within these networks were detected using the Louvain algorithm and topologically and functionally compared across stages using the normalized mutual information (NMI) metric and pathway enrichment analysis, respectively. We also used Short Time-series Expression Miner (STEM) algorithm to detect potential biomarkers having a role in CRC.

RESULTS

Sixteen Thousand Sixty Two DEGs were identified between various stages (p-value ≤ 0.05). Comparing communities of different stages revealed that neighboring stages were more similar to each other than non-neighboring stages, at both topological and functional levels. A functional analysis of 24 cancer-related pathways indicated that several signaling pathways were enriched across all stages. However, the stage-unique networks were distinctly enriched only for a subset of these 24 pathways (e.g., MAPK signaling pathway in stages I-III and Notch signaling pathway in stages III and IV). We identified potential biomarkers, including HOXB8 and WNT2 with increasing, and MTUS1 and SFRP2 with decreasing trends from stages I to IV. Extracting subnetworks of 10 cancer-relevant genes and their interacting first neighbors (162 genes in total) revealed that the connectivity patterns for these genes were different across stages. For example, BRAF and CDK4, members of the Ser/Thr kinase, up-regulated in cancer, displayed changing connectivity patterns from stages I to IV.

CONCLUSIONS

Here, we report molecular and modular networks for various stages of CRC, providing a pseudo-temporal view of the mechanistic changes associated with the disease. Our analysis highlighted similarities at both functional and topological levels, across stages. We further identified stage-specific mechanisms and biomarkers potentially contributing to the progression of CRC.

The roles of HOXB8 through activating Wnt/β-catenin and STAT3 signaling pathways in the growth, migration and invasion of ovarian cancer cells

Ovarian cancer is one of the gynecological malignancies ranked third in incidence and first in mortality in the world. Homoboxb8 (HOXB8) has been demonstrated to play crucial roles in various tumors. However, the function of HOXB8 in ovarian cancer remains to be addressed. Quantitative real-time polymerase chain reaction, immunohistochemistry staining and western blot assays demonstrated that HOXB8 expression was up-regulated in human ovarian cancer tissues and cells. The results of CCK-8 and colony formation assays indicated that HOXB8 promoted the proliferation of ovarian cancer cells. Transwell and immunofluorescence (IF) staining assay demonstrated that HOXB8 promoted the migration and invasion of ovarian cancer cells. Importantly, mechanism analysis implied that HOXB8 increased the expression of β-catenin and phosphorylation of STAT3, and the downstream target molecules of Cyclin D1, c-Myc, TWIST1, MMP7 and MMP9, indicating that HOXB8 could promote the activation of Wnt/β-catenin and STAT3 pathways. Moreover, HOXB8 knockdown suppressed xenograft tumor growth, and inhibited the levels of HOXB8 and Ki-67, while increasing the level of E-cadherin in mice. In conclusion, HOXB8 promotes cell proliferation, migration and invasion through modulating Wnt/β-catenin and STAT3 signaling pathways in ovarian cancer, suggesting that HOXB8 may provide a promising target for the therapy of ovarian cancer.

GRAPHICAL ABSTRACT

Downstream of the HOX genes: explaining conflicting tumour suppressor and oncogenic functions in cancer

The HOX genes are a highly conserved group of transcription factors that have key roles in early development, but which are also highly expressed in most cancers. Many studies have found strong associative relationships between the expression of individual HOX genes in tumours and clinical parameters including survival. For the majority of HOX genes, high tumour expression levels seem to be associated with a worse outcome for patients, and in some cases this has been shown to result from the activation of pro-oncogenic genes and pathways. However, there are also many studies that indicate a tumour suppressor role for some HOX genes, sometimes with conclusions that contradict earlier work. In this review, we have attempted to clarify the role of HOX genes in cancer by focusing on their downstream targets as identified in studies that provide experimental evidence for their activation or repression. On this basis, the majority of HOX genes would appear to have a pro-oncogenic function, with the notable exception of HOXD10, which acts exclusively as a tumour suppressor. HOX proteins regulate a wide range of target genes involved in metastasis, cell death, proliferation, and angiogenesis, and activate key cell signalling pathways. Furthermore, for some functionally related targets, this regulation is achieved by a relatively small subgroup of HOX genes.

Dysregulation of FOXD2-AS1 promotes cell proliferation and migration and predicts poor prognosis in oral squamous cell carcinoma: a study based on TCGA data

FOXD2 adjacent opposite strand RNA 1 (FOXD2-AS1) plays an important role in the pathogenesis of some cancers. However, its functional role in oral squamous cell carcinoma (OSCC) remains largely unknown. In this study, we conducted expressional and functional analyses of FOXD2-AS1 using data from the Cancer Genome Atlas (TCGA) and in vitro OSCC assays. FOXD2-AS1 dysregulation was remarkably associated with radiation therapy, anatomic location, high histologic grade, and lymphovascular invasion (P < 0.05). A nomogram based on FOXD2-AS1 expression was constructed for use as a diagnostic indicator for OSCC patients, and multivariate cox regression analysis showed that FOXD2-AS1 expression was an independent prognostic factor for OSCC patients. KEGG, gene set enrichment analysis, and immune infiltration evaluations indicated that FOXD2-AS1 was involved in tumor progression via epithelial-to-mesenchymal transition and cell cycle regulation and was negatively associated with mast cell, DCs, iDCs, and B cells. FOXD2-AS1 silencing suppressed the proliferation and migration of Cal27 cells. Our findings showed that an aberrantly high FOXD2-AS1 expression predicts poor prognosis in OSCC; FOXD2-AS1 may act as an oncogenic protein by regulating cell proliferation and migration and may suppress adaptive immunity by modulating the number and function of antigen-presenting cells.

Downregulation of long non-coding RNA MAFG-AS1 represses tumorigenesis of colorectal cancer cells through the microRNA-149-3p-dependent inhibition of HOXB8

Background

Colorectal cancer (CRC) is considered as the second common death-induced cancer. More recently, association of long non-coding RNAs (lncRNAs) with CRC has been extensively investigated. Therefore, the present study was performed to determine whether lncRNA MAF BZIP Transcription Factor G Antisense RNA 1 (MAFG-AS1) could regulate biological activities of CRC cells and unravel the underlying mechanisms.

Methods

CRC and corresponding adjacent tissues were collected to determine the expression of lncRNA MAFG-AS1, microRNA-149-3p (miR-149-3p) and homeobox B8 (HOXB8) by RT-qPCR. Dual luciferase reporter gene assay was used to explore the targeting relationship between miR-149-3p and lncRNA MAFG-AS1 and between miR-149-3p and HOXB8, followed by RNA immunoprecipitation for verification. Migration, proliferation, invasion, and apoptosis of HCT116 and LoVo cells were examined when lncRNA MAFG-AS1 was silenced or miR-149-3p was overexpressed. Furthermore, tumorigenicity of HCT116 and LoVo cells was measured in vivo by tumor xenograft in nude mice.

Results

LncRNA MAFG-AS1 and HOXB8 were found to be highly expressed in CRC tissues and cells, while miR-149-3p was under-expressed. LncRNA MAFG-AS1 negatively regulated miR-149-3p while miR-149-3p downregulated HOXB8. In addition, lncRNA MAFG-AS1 silencing by shRNA or miR-149-3p upregulation by mimic suppressed the migration, proliferation, invasion and tumorigenesis but promoted the apoptosis of HCT116 and LoVo cells.

Conclusion

Taken together, lncRNA MAFG-AS1 downregulation inhibits the malignant behaviors of CRC cells by upregulating miR-149-3p and downregulating HOXB8, providing a potential therapeutic target for CRC treatment.

miR-27a-3p Functions as a Tumor Suppressor and Regulates Non-Small Cell Lung Cancer Cell Proliferation via Targeting HOXB8

MicroRNA-27a-3p has been implicated to play crucial roles in human cancers. However, the biological role and underlying mechanisms of microRNA-27a-3p in regulating nonsmall lung cancer remain unclear. MicroRNA-27a-3p expression levels in non-small lung cancer cell lines were detected by quantitative real-time polymerase chain reaction, using a normal cell line as control. The effects of microRNA-27a-3p on cell proliferation and apoptosis were analyzed by Cell Counting Kit-8 assay and flow cytometry assay. Luciferase activity reporter assay and Western blot were conducted to validate the potential targets of miR27a-3p after preliminary screening by TargetScan. Effect of microRNA-27a-3p or homeobox B8 on the overall survival of patients with non-small lung cancer was analyzed at Kaplan-Meier Plotter website. MicroRNA-27a-3p expression levels were significantly reduced in non-small lung cancer cell lines compared with normal cell line. Overexpression of microRNA-27a-3p inhibits non-small lung cancer cell proliferation but promotes cell apoptosis. Homeobox B8 was further validated as a functional target of microRNA-27a-3p. Collectively, our results indicated that microRNA-27a-3p acts as a tumor suppressor in non-small lung cancer via targeting homeobox B8.

LINC01006 promotes cell proliferation and metastasis in pancreatic cancer via miR-2682-5p/HOXB8 axis

Background

Pancreatic cancer (PC) is one of the deadliest cancers about the digestive system. Recent researches have validated that long non-coding RNAs (lncRNAs) play vital roles in various cancers, while the function of LINC01006 in PC is rarely clarified.

Aim of the study

Investigation of the specific role of LINC01006 in PC.

Methods

LINC01006 expression was examined by RT-qPCR. CCK-8, EdU, transwell, wound healing, and western blot assays were carried out to explore the function of LINC01006 in PC. The interaction among LINC01006, miR-2682-5p and HOXB8 was verified by luciferase reporter, RIP and ChIP assays.

Results

The expression of LINC01006 was markedly upregulated in PC tissues and cells. Furthermore, LINC01006 knockdown inhibited PC cell proliferation, invasion and migration, and upregulation of LINC01006 led to the opposite results. Besides, miR-2682-5p expression was downregulated and negatively regulated by LINC01006 in PC. Meanwhile, LINC01006 could bind with miR-2682-5p in PC. Moreover, miR-2682-5p negatively regulated HOXB8 expression and there was a binding site between miR-2682-5p and HOXB8 in PC. Additionally, miR-2682-5p overexpression or HOXB8 knockdown rescued the promotive effects of LINC01006 upregulation on PC cell progression. Similarly, miR-2682-5p inhibition or HOXB8 overexpression countervailed the repressive role of LINC01006 downregulation in PC cell progression. In addition, the transcription factor HOXB8 could activate LINC01006 transcription in PC.

Conclusions

LINC01006 promotes cell proliferation and metastasis in pancreatic cancer via miR-2682-5p/HOXB8 axis, which may facilitate the treatment for PC.

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.

Silibinin inhibits migration and invasion of breast cancer MDA-MB-231 cells through induction of mitochondrial fusion

Human triple negative breast cancer cells, MDA-MB-231, show typical epithelial to mesenchymal transition associated with cancer progression. Mitochondria play a major role in cancer progression, including metastasis. Changes in mitochondrial architecture affect cellular migration, autophagy and apoptosis. Silibinin is reported to have anti-breast cancer effect. We here report that silibinin at lower concentrations (30-90 μM) inhibits epithelial to mesenchymal transition (EMT) of MDA-MB-231, by increasing the expression of epithelial marker, E-cadherin, and decreasing the expression of mesenchymal markers, N-cadherin and vimentin. Besides, silibinin inhibition of cell migration is associated with reduction in the protein expression of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) and paxillin. In addition, silibinin treatment increases mitochondrial fusion through down-regulating the expression of mitochondrial fission-associated protein dynamin-related protein 1 (DRP1) and up-regulating the expression of mitochondrial fusion-associated proteins, optic atrophy 1, mitofusin 1 and mitofusin 2. Silibinin perturbed mitochondrial biogenesis via down-regulating the levels of mitochondrial biogenesis regulators including mitochondrial transcription factor A (TFAM), peroxisome proliferator-activated receptor gamma coactivator (PGC1) and nuclear respiratory factor (NRF2). Moreover, DRP1 knockdown or silibinin inhibited cell migration, and MFN1&2 knockdown restored it. Mitochondrial fusion contributes to silibinin's negative effect on cell migration. Silibinin decreased reactive oxygen species (ROS) generation, leading to inhibition of the NLRP3 inflammasome activation. In addition, knockdown of mitofusin 1&2 (MFN 1&2) relieved silibinin-induced inhibition of NLRP3 inflammasome activation. Repression of ROS contributes to the inhibition of the expression of NLRP3, caspase-1 and IL-β proteins as well as of cell migration. Taken together, our study provides evidence that silibinin impairs mitochondrial dynamics and biogenesis, resulting in reduced migration and invasion of the MDA-MB-231 breast cancer cells.

Long non-coding RNA MIF-AS1 promotes breast cancer cell proliferation, migration and EMT process through regulating miR-1249-3p/HOXB8 axis

Breast cancer (BC) is one of the leading cause of cancer-related death among females worldwide. Mounting evidences indicate that long non-coding RNAs (lncRNAs) were involved in tumor progression by acting as either oncogenes or tumor suppressors in multiple cancers. In this study, we focused on the function and mechanism of lncRNA Migration Inhibitory Factor Antisense RNA 1 (MIF-AS1) in BC. qRT-PCR showed that MIF-AS1 was upregulated in BC tissues and cells. To detect its bio-function, a series of loss-of-function assays were carried out. Thereafter, we found that MIF-AS1 depletion inhibited BC cell proliferation, migration and epithelial-mesenchymal transition (EMT). Recently, increasing studies indicate that lncRNAs can function as competing endogenous RNAs (ceRNAs). Using bioinformatics analysis and luciferase reporter assay, we identified that MIF-AS1 regulated the level of Homeobox B8 (HOXB8) via binding to miR-1249-3p. Taken all together, our findings proved that MIF-AS1 acted as a ceRNA by modulating miR-1249-3p/HOXB8 axis in breast cancer. LncRNA MIF-AS1 might be a new biomarker and therapeutic target for BC patients.

RETRACTED: miR-27b Targets HOXB8 to Inhibit Malignant Behaviors of Osteosarcoma

MicroRNAs function as either tumor suppressor or oncogene in human cancers. This study aimed to explore the role of miR-27b in osteosarcoma. Expression of miR-27b or homeobox B8 in osteosarcoma cell lines was analyzed by quantitative real-time polymerase chain reaction and Western blot, respectively. Luciferase activity reporter assay and Western blot were conducted to explore the association between miR-27b and homeobox B8. Cell Counting Kit-8, colony formation assay, and wound-healing assay were performed to investigate the role of miR-27b or homeobox B8 on cell proliferation, colony formation, and cell migration. Expression of miR-27b was significantly reduced, while homeobox B8 was increased in osteosarcoma cell lines. In addition, homeobox B8 was validated as a direct target of homeobox B8. Moreover, miR-27b regulates osteosarcoma cell proliferation, colony formation, and migration through targeting homeobox B8. Taken together, our study provides novel insight into the progression of osteosarcoma, and the miR-27b–homeobox B8 axis identified may be developed as therapeutic targets against hepatocellular carcinoma in the future.