CMTM4 is frequently downregulated and functions as a tumour suppressor in clear cell renal cell carcinoma

Abstract

BackgroundChemokine-like factor (CKLF)-like MARVEL transmembrane domain-containing family (CMTM) is a gene family involved in multiple malignancies. CMTM4 is a member of this family and is located at chromosome 16q22.1, a locus that harbours a number of tumour suppressor genes. It has been defined as a regulator of cell cycle and division in HeLa cells; however, its roles in tumourigenesis remain poorly studied.MethodsAn integrated bioinformatics analysis based on the array data from the GEO database was conducted to view the differential expression of CMTM4 across multiple cancers and their corresponding control tissues. Primary clear cell renal cell carcinoma (ccRCC) and the paired adjacent non-tumour tissues were then collected to examine the expression of CMTM4 by western blotting, immunohistochemistry, and quantitative RT-PCR. The ccRCC cell lines A498 and 786-O and the normal renal tubular epithelial cell line HK-2 were also tested for CMTM4 expression by western blotting. Cell Counting Kit-8 (CCK-8) and viable cell counting assays were used to delineate the growth curves of 786-O cells after CMTM4 overexpression or knockdown. Wound healing and transwell assays were performed to assess the cells’ ability to migrate. The effects of CMTM4 on cellular apoptosis and cell cycle progression were analysed by flow cytometry, and cell cycle hallmarks were detected by western blotting and RT-PCR. The xenograft model in nude mice was used to elucidate the function of CMTM4 in tumourigenesis ex vivo.ResultsBy omic data analysis, we found a substantial downregulation of CMTM4 in ccRCC. Western blotting then confirmed that CMTM4 was dramatically reduced in 86.9 % (53/61) of ccRCC tissues compared with the paired adjacent non-tumour tissues, as well as in the 786-O and A498 ccRCC cell lines. Restoration of CMTM4 significantly suppressed 786-O cell growth by inducing G2/M cell cycle arrest and p21 upregulation, and cell migration was also inhibited. However, knockdown of CMTM4 led to a completely opposite effect on these cell behaviours. Overexpression of CMTM4 also markedly inhibited the tumour xenograft growth in nude mice.ConclusionsCMTM4 is downregulated and exhibits tumour-suppressor activities in ccRCC, and could be exploited as a target for ccRCC treatment.

Alterations in genetic pathways following radiotherapy for head and neck cancer

“…To our knowledge, this is one of the first in vivo studies comparing the differences in gene and pathway expression in RT naïve HNC vs recurrent previously irradiated HNC samples. Our study identified a differential expression of various genes, with previously described associations with HNC stem cells, proliferation, and radioresistance . Most notably, our post‐RT samples had a significant downregulation of the Wnt and Myc pathways.…”

“…CMTM4 is a tumor suppressor gene characterized by G2/M phase regulation, p21 upregulation, and inhibition of cell migration . The downregulation of CMTM4 has been described in clear cell renal cell carcinoma, with restoration of expression significantly suppressing cell growth in vitro and in xenograft models . Our study suggests that the decreased expression of these tumor suppressor genes may play a larger role in the carcinogenesis and progression of RT naive tumors, but may have a limited role in the growth of recurrent previously irradiated HNC.…”

“…IGFBP‐rP4 can affect the interaction between growth factors and cell surface receptors, and has been suggested as a novel putative tumor suppressor in vitro . CMTM4 is a tumor suppressor gene characterized by G2/M phase regulation, p21 upregulation, and inhibition of cell migration . The downregulation of CMTM4 has been described in clear cell renal cell carcinoma, with restoration of expression significantly suppressing cell growth in vitro and in xenograft models .…”

Aloe-Emodin Ameliorates Renal Fibrosis Via Inhibiting PI3K/Akt/mTOR Signaling PathwayIn VivoandIn Vitro

“…Assessment of cell proliferation was done at AE (20, 40, 60, 80, 100 lM) with an optical density of 450 nm. 27 Triplicate wells were performed in each assay, and the assay was replicated at least four times.…”

Overexpression of G6PD Represents a Potential Prognostic Factor in Clear Cell Renal Cell Carcinoma

“…Therefore, it is extremely important for us to further explore the molecular mechanisms of this deadly disease. Identification of novel genes that are potentially recognized as diagnostic and prognostic biomarkers and functionally involved in the ccRCC tumorigenic initiation and progression may improve early diagnosis of ccRCC and further help to develop more strategies for ccRCC treatment 6.…”