Pro-Angiogenic and Pro-Inflammatory Regulation by lncRNA MCM3AP-AS1-Mediated Upregulation of DPP4 in Clear Cell Renal Cell Carcinoma

Abstract

Clear cell renal cell carcinoma (ccRCC) represents the most common type of renal cell carcinoma (RCC) in adults, in addition to the worst prognosis among the common epithelial kidney tumors. Inflammation and angiogenesis seem to potentiate tumor growth and metastasis of the malignancy. The current study explored the contributions of the lncRNA MCM3AP-AS1 in tumor-associated inflammation and angiogenesis in ccRCC with a specific focus on its transcriptional regulation and its interactions with transcription factor E2F1 and DPP4. Tumor tissues and matched adjacent non-tumor tissues were collected from 78 ccRCC patients. Methylation-specific PCR and ChIP assays were applied to detect the methylation at the promoter region of MCM3AP-AS1. Dual-luciferase reporter assay, RIP, RNA pull-down, and ChIP assays were employed to confirm the interactions between MCM3AP-AS1, E2F1, and DPP4. Nude mice were subcutaneously xenografted with human ccRCC cells. Cell proliferation was evaluated by CCK-8 assays and EDU staining in ccRCC cells in vitro and by immunohistochemical staining of Ki67 in vivo. Inflammation was examined by detecting the secretion of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6). Pro-angiogenic ability of ccRCC cells was assessed by the co-culture with human umbilical vein endothelial cells (HUVEC) in vitro and by microvessel density (MVD) measurements and angiogenesis in the chicken chorioallantoic membrane. MCM3AP-AS1 was highly-expressed in ccRCC and associated with poor patient survival. Demethylation of MCM3AP-AS1 was noted in ccRCC tissues and cells. Over-expression of MCM3AP-AS1 enhanced cell proliferation, the release of pro-inflammatory cytokines, and the tube formation of HUVECs in cultured human Caki-1 and 786-O cells. MCM3AP-AS1 was shown to enhance the E2F1 enrichment at the DPP4 promoter, to further increase the expression of DPP4. Knockdown of DPP4 could abate pro-angiogenic and pro-inflammatory abilities of MCM3AP-AS1 in ccRCC cells. Pro-angiogenic and pro-inflammatory abilities of MCM3AP-AS1 in vivo were confirmed in mice subcutaneously xenografted with human ccRCC cells. Our findings demonstrate a novel mechanism by which lncRNA MCM3AP-AS1 exerts pro-angiogenic and pro-inflammatory effects, highlighting the potential of MCM3AP-AS1 as a promising target for treating ccRCC.

MCM3AP-AS1: An Indispensable Cancer-Related LncRNA

“…MCM3AP-AS1 was also found to be upregulated in Burkitt lymphoma, glioblastoma, LC, nasopharyngeal carcinoma, clear cell renal cell carcinoma, pancreatic cancer, and papillary thyroid cancer tissues compared to the corresponding normal tissues (Yang et al, 2017(Yang et al, , 2019Liang et al, 2019;Guo et al, 2020;Li et al, 2020b;Qiu et al, 2020;Sun et al, 2020) In contrast to the above findings, MCM3AP-AS1 expression is markedly downregulated in CSCC tissue samples and predicts a poor outcome. Overexpression of MCM3AP-AS1 reduces CSCC cell proliferation, and MCM3AP-AS1 acts as a tumor suppressor during CSCC development and progression.…”

“…Qiu et al demonstrated that MCM3AP-AS1 could interact with E2F1 and enhance the enrichment of E2F1 at the DPP4 promoter, increasing the expression of DPP4. As a result, MCM3AP-AS1 promoted angiogenesis and inflammation in clear cell renal cell carcinoma (Qiu et al, 2020). Another study also revealed that MCM3AP-AS1 can recruit DNMT1/DNMT3 (A/B) to induce methylation of NPY1R promoter.…”

Long noncoding RNA MCM3AP‐AS1 enhances cell proliferation and metastasis in colorectal cancer by regulating miR‐193a‐5p/SENP1

“…MCM3AP-AS1 was originally reported to be overexpressed in glioblastoma 17 and the up-regulation of MCM3AP-AS1 stimulated cell migration and tube formation of clear cell renal cell carcinoma. 23 MCM3AP-AS1 could also exert a carcinogenic role in hepatocellular carcinoma and papillary thyroid cancer. 20,24 We revealed that MCM3AP-AS1 was aberrantly expressed in CRC tissues and associated with poor prognosis of CRC patients.…”

“…Recent studies have suggested that MCM3AP‐AS1 could play a key role in human cancers. MCM3AP‐AS1 was originally reported to be overexpressed in glioblastoma 17 and the up‐regulation of MCM3AP‐AS1 stimulated cell migration and tube formation of clear cell renal cell carcinoma 23 . MCM3AP‐AS1 could also exert a carcinogenic role in hepatocellular carcinoma and papillary thyroid cancer 20,24 .…”

Differential Expression of Long Noncoding RNAs in Patients with Coronary Artery Disease

“…Although several angiogenesisregulating lncRNAs such as MANTIS, MEG3, MIAT, MALAT1, and SENCR were shown to have a significant role in angiogenesis and cardiovascular diseases [Yu and Wang, 2018], lncRNA studies conducted in this field are still limited. Significance of several angiogenesis-regulating lncRNAs such as MCM3AP-AS1 [Li et al, 2020;Qiu et al, 2020] have not been uncovered in the development of cardiovascular disease. Accordingly, in this study, we aimed to assess the expression levels of 4 candidate angiogenesis regulating lncRNAs -MEG3, MIAT, MALAT1, and MCM3AP-AS1 -in patients with CAD who underwent coronary angiography and to investigate the diagnostic and therapeutic potentials of these lncRNAs for CAD.…”