Identification of angiogenesis-related subtypes, the development of prognostic models, and the landscape of tumor microenvironment infiltration in colorectal cancer.

Background: Angiogenesis is one of the most prominent markers of cancer progression and contributes to tumor metastasis and prognosis. Anti-angiogenic drugs have proven effective in treating metastatic colorectal cancer. However, there is some uncertainty regarding the potential role of angiogenesis-related genes in the tumor microenvironment. Methods: We analyzed 1,214 colorectal cancer samples to identify alterations in angiogenesis-related genes (ARGs), and then correlated angiogenesis with clinical features, prognosis, and TME. The ARGs expression profiles in colorectal cancer were analyzed using three computational methods (CIBERSORT, ssGSEA, and MCPcounter) and provided a systematic immune landscape. Patients with CRC were classified into two subtypes based on consensus clustering analysis of angiogenesis-related genes. The revealed differentially expressed genes between the two subtypes were used to create and validate ARGscore prognostic models. In addition, we collected eight colorectal cancer patient specimens and performed RT-qPCR to validate the signature gene expression. Results: We assessed the expression patterns of ARGs in colorectal cancer. We identified two molecular subtypes and confirmed that the expression of ARGs was associated with prognosis and TME characteristics. Based on differentially expressed genes between subtypes, we constructed ARGscore and evaluated their predictive power for the survival of colorectal cancer patients. We also developed an accurate nomogram to make the ARGscore more clinically useful. In addition, ARGscore was significantly correlated with microsatellite instability, cancer stem cells, and chemotherapeutic drug sensitivity. Patients with ARGscore-low characterized by immune activation and microsatellite instability high had a better prognosis. Conclusion: ARGs expression influenced the prognosis, clinicopathological features, and tumor stromal immune microenvironment in colorectal cancer. We developed a new risk model, ARGscore, for the treatment and prognosis of CRC patients and validated its promising predictive power. These findings will enable us to understand colorectal cancer better, assess prognoses, and develop more effective treatment options.

Reduced expression of microRNA-432-5p by DNA methyltransferase 3B leads to development of colorectal cancer through upregulation of CCND2.

BACKGROUND: The tumor suppressive function of microRNA-432-5p (miR-432-5p) has been reported in several human malignances. This study aimed to probe the expression profile and role of miR-432-5p in colorectal cancer (CRC) and the molecular mechanism. METHODS: Differentially expressed miRNAs between CRC and healthy samples were screened using a miRNA expression dataset GSE136020. The related molecules were identified by integrated bioinformatic analyses. A murine model of primary CRC was established and xenograft tumors were induced in mice. Altered expression of DNMT3B, miR-432-5p and cyclin D2 (CCND2) were introduced in CRC cells to determine their roles in the development of CRC. RESULTS: miR-432-5p was downregulated in CRC according to the GSE136020 dataset. CCND2 mRNA was confirmed as a target of miR-432-5p. miR-432-5p was downregulated, whereas CCND2 was abundantly expressed in CRC tissues and cells. DNA methyltransferase 3B (DNMT3B) induced DNA methylation at the CpG island of miR-432-5p to inhibit its expression. miR-432-5p mimic significantly suppressed tumorigenesis of primary CRC in mice. Downregulation of DNMT3B weakened viability, invasiveness, blocked the cell cycle progression of CRC cells in vitro, and inhibited xenograft tumor growth and metastasis in nude mice. However, additional downregulation of miR-432-5p or upregulation of CCND2 restored the malignant behaviors of CRC cells. CONCLUSION: This study showed that DNMT3B induced DNA methylation and downregulation of miR-432-5p to promote development of CRC by upregulating CCND2.

BTF3-mediated regulation of BMI1 promotes colorectal cancer through influencing epithelial-mesenchymal transition and stem cell-like traits.

The critical roles of transcription factors in cell differentiation and the delineation of cell phenotypes have been reported. The current study aimed to characterize the functions of the basic transcription factor 3 (BTF3) gene and its regulation of the intestinal stem cell marker B cell-specific Moloney murine leukemia virus insertion site 1 (BMI1) gene in colorectal cancer (CRC). Stem cell-like traits and epithelial-mesenchymal transition (EMT) of cultured human CRC cell line HCT116 were evaluated by CD133+ subpopulation counting, colony formation, tumorosphere generation, and expression of EMT-specific markers and stem cell markers. The interaction of BTF3 with BMI1 was analyzed. BTF3 was overexpressed in CRC tissues, which was associated with poor patient survival. BTF3 knockdown impaired the retention of stem cell-like traits of HCT116 and inhibited the EMT of HCT116 cells. BMI1 expression changed in a BTF3-dependent manner, and its overexpression could partially restore stem cell-like traits and EMT of cultured HCT116 cells after BTF3 knockdown. In parallel, treatment with the BMI1 inhibitor PTC-209 mimicked the effects of BTF3 knockdown on stem cell-like traits and EMT of cultured HCT116 cells. Together, these results support the notion that BTF3 and BMI1 are potential therapeutic targets to limit CRC metastasis.

NEDD4 triggers FOXA1 ubiquitination and promotes colon cancer progression under microRNA-340-5p suppression and ATF1 upregulation.

NEDD4 is an E3 ubiquitin ligase that recognizes substrates through protein-protein interactions and is involved in cancer development. This study aimed to elucidate the function of NEDD4 in colon cancer (CC) progression and its mechanism of action. NEDD4 was abundantly expressed in CC tissues and cells, and the overexpression of NEDD4 promoted the growth and metastasis of xenograft tumours as well as the tumorigenesis rate of primary CC in mouse models. In in vitro experiments, the silencing (or upregulation) of NEDD4 inhibited (or increased) the viability, invasion, and epithelial-to-mesenchymal transition of CC cells. The binding relationships between NEDD4 and FOXA1, FOXA1 and microRNA (miRNA)-340-5p, and miR-340-5p and ATF1 were validated by Co-immunoprecipitation, chromatin immunoprecipitation and luciferase assays, and NEDD4 was demonstrated to trigger FOXA1 ubiquitination and degradation. FOXA1 transcriptionally activated miR-340-5p, which subsequently bound to ATF1 mRNA. The upregulation of FOXA1 or miR-340-5p or the downregulation of ATF1 blocked certain functions of NEDD4 in CC cells. Altogether, NEDD4 was demonstrated to trigger FOXA1 ubiquitination and promote CC progression under the involvement of microRNA-340-5p suppression and ATF1 upregulation.

Long non-coding RNA CERS6-AS1 facilitates the oncogenicity of pancreatic ductal adenocarcinoma by regulating the microRNA-15a-5p/FGFR1 axis.

The long non-coding RNA CERS6 antisense RNA 1 (CERS6-AS1) has critical regulatory roles in breast cancer progression. Here, we determined CERS6-AS1 expression in pancreatic ductal adenocarcinoma (PDAC) and the roles of CERS6-AS1 in PDAC carcinogenesis. The mechanisms underlying the regulatory actions of CERS6-AS1 in PDAC cells were elucidated in detail. CERS6-AS1 expression was evidently increased in PDAC tissues and cell lines. Patients with PDAC having high CERS6-AS1 expression had shorter overall survival periods than those having low CERS6-AS1 expression. Functionally, the knockdown of CERS6-AS1 attenuated the proliferation, migration, and invasion and stimulated apoptosis of PDAC cells in vitro. Additionally, CERS6-AS1 depletion decreased PDAC tumor growth in vivo. Mechanistically, CERS6-AS1 could competitively bind to microRNA-15a-5p (miR-15a-5p) and effectively work as a molecular sponge in PDAC cells, resulting in the upregulation of fibroblast growth factor receptor 1 (FGFR1), a direct target of miR-15a-5p. Rescue experiments revealed that miR-15a-5p downregulation or FGFR1 restoration rescued the effects of CERS6-AS1 knockdown on the behaviors of PDAC cells. In conclusion, CERS6-AS1 promoted the oncogenicity of PDAC by serving as a competing endogenous RNA to sequester miR-15a-5p and increase FGFR1 expression, which highlights the potential of the CERS6-AS1/miR-15a-5p/FGFR1 pathway as an effective target for cancer therapy.

microRNA-548b suppresses aggressive phenotypes of hepatocellular carcinoma by directly targeting high-mobility group box 1 mRNA.

Background and purpose: An increasing number of studies have revealed that microRNAs (miRNAs) are the main drivers of hepatocarcinogenesis including progression to later stages of liver cancer. Recently, miR-548b was identified as a cancer-related miRNA in glioma and tongue squamous cell carcinoma. Nonetheless, the expression pattern and specific roles of miR-548b in hepatocellular carcinoma (HCC) have not yet been clarified. Methods: Expression levels of miR-548b in HCC tissues and cell lines were measured by reverse-transcription quantitative PCR. In vitro and in vivo functional assays were performed to determine the effects of miR-548b on the malignant phenotypes of HCC cells. In addition, the molecular mechanisms by which miR-548b regulates the initiation and progression of HCC were investigated in detail. Results: miR-548b expression was weak in HCC tissues and cell lines. The low miR-548b expression significantly correlated with tumor size, TNM stage, and venous infiltration of HCC. In addition, exogenous miR-548b expression suppressed HCC cell proliferation, colony formation, and metastasis and induced apoptosis in vitro. Silencing of miR-548b exerted an opposite effect on these characteristics of HCC cells. Furthermore, miR-548b overexpression hindered tumor growth in vivo. Mechanistic analysis identified high-mobility group box 1 (HMGB1) as a direct target gene of miR-548b in HCC cells. Moreover, an HMGB1 knockdown reproduced the effects of miR-548b upregulation on HCC cells. Recovered HMGB1 expression reversed the effects of miR-548b on HCC cells. Notably, miR-548b overexpression deactivated the PI3K-AKT pathway in HCC cells in vitro and in vivo. Conclusion: Our findings provide the first evidence that miR-548b restrains HCC progression, at least partially, by downregulating HMGB1 and deactivating the PI3K-AKT pathway. Thus, miR-548b might be a novel target for the development of new therapies for HCC.