LINC00665 up-regulates SIN3A expression to modulate the progression of colorectal cancer via sponging miR-138-5p

The functions and mechanisms of long non-coding RNA in colorectal cancer

CRC poses a significant challenge in the global health domain, with a high number of deaths attributed to this disease annually. If CRC is detected only in its advanced stages, the difficulty of treatment increases significantly. Therefore, biomarkers for the early detection of CRC play a crucial role in improving patient outcomes and increasing survival rates. The development of a reliable biomarker for early detection of CRC is particularly important for timely diagnosis and treatment. However, current methods for CRC detection, such as endoscopic examination, blood, and stool tests, have certain limitations and often only detect cases in the late stages. To overcome these constraints, researchers have turned their attention to molecular biomarkers, which are considered a promising approach to improving CRC detection. Non-invasive methods using biomarkers such as mRNA, circulating cell-free DNA, microRNA, LncRNA, and proteins can provide more reliable diagnostic information. These biomarkers can be found in blood, tissue, stool, and volatile organic compounds. Identifying molecular biomarkers with high sensitivity and specificity for the early and safe, economic, and easily measurable detection of CRC remains a significant challenge for researchers.

LINC00665: A Promising Biomarker in Gastrointestinal Tumors

An increasing volume of studies has reported that long non-codingRNAs (lncRNAs) are involved in the carcinogenesis of many different cancers. Especially in gastrointestinal tumors, lncRNAs are found to participate in various physiological and pathological processes. LncRNAs can regulate gene expression at multiple levels, including transcriptional, post-transcription, translational, and post-translational levels. Long intergenic non-protein coding RNA 665(LINC00665), a novel cancer-related lncRNA, is frequently dysregulated in multiple gastrointestinal tumors, including gastric and colorectal cancers, hepatocellular carcinoma, and so on. In this review, we analyzed the expression and prognostic value of LINC00665 in human gastrointestinal tumors, systematically summarized the current literature about the clinical significance of this lncRNA, and explored the regulatory mechanisms of LINC00665 as a competing endogenous RNA (ceRNA) in tumor progression. Consequently, we concluded that LINC00665 might act as a prognostic biomarker and a potential target for gastrointestinal tumor diagnosis and treatment.

Regulatory mechanism of RNA binding motif protein 15-mediated N6 methyladenosine modification in proliferation, invasion, and migration of colorectal cancer cells

This study aims to explore the regulatory mechanism of RNA binding motif protein 15 (RBM15) on the proliferation, invasion, and migration of colorectal cancer (CRC) cells. RBM15, KLF1, or SIN3A expression in CRC tissues and cells was detected by RT-qPCR or Western blot. CRC cell functions were measured by CCK-8, colony formation, and Transwell assays after RBM15 intervention. MeRIP and RIP measured N6 methyladenosine (m6 A) and IGF2BP3 enrichment on KLF1 mRNA. ChIP and dual-luciferase analyzed KLF1 enrichment on SIN3A promoter. Combined experiments verified the effect of KLF1/SIN3A on CRC cell functions. Lung/liver metastasis models were established to validate the effect of RBM15 on CRC in vivo. RBM15, KLF1, and SIN3A were highly expressed in CRC. RBM15 knockdown reduced the proliferation, invasion, and migration of CRC cells in vitro. Mechanistically, RBM15 facilitated KLF1 mRNA stability and expression through IGF2BP3-dependent m6 A modification, thus promoting KLF1 enrichment on the SIN3A promoter and activating SIN3A transcription. Overexpression of KLF1 or SIN3A reversed the inhibitory effect of RBM15 knockdown on CRC cells. In vivo experiments verified that RBM15 promoted tumorigenesis and lung/liver metastasis via KLF1/SIN3A axis. In conclusion, RBM15 stimulated CRC proliferation and metastasis by promoting the KLF1/SIN3A axis through IGF2BP3-dependent m6 A modification.

Prognostic and clinicopathological values of LINC00665 in cancers: a systematic review and China population-based meta-analysis

BACKGROUND

Recent studies have uncovered that the aberrant expression of LINC00665 contributes to the malignant pathological process of various cancers and is closely related to the unfavorable prognosis of patients with cancer. However, a systematic analysis of the prognostic and clinicopathologic values of LINC00665 in cancers has not been conducted.

OBJECTIVE

We aim to clarify the association of LINC00665 expression with patient survival and clinicopathologic phenotypes in cancers.

METHODS

An electronic search of PubMed, Embase and Web of Science was performed to select eligible literature. Pooled hazard ratio (HR) and odds ratio (OR) were calculated to assess the clinical importance of LINC00665. The fixed-effects model was used to analyze the combined HR values and 95% CI when the studies had no significant heterogeneity (P > 0.1 for the Chi-square test or I2 < 50%). Begg's test and sensitivity analysis were also conducted. This study was registered in The International Prospective Register of Systematic Reviews (PROSPERO registration number: CRD42021290123).

RESULTS

A total of 710 patients from 10 eligible studies were enrolled in this meta-analysis, which was based on China population. The pooled results of this analysis revealed that high-level expression of LINC00665 was notably correlated with poor overall survival (HR = 2.08, 95% CI = 1.57-2.75) and recurrence-free survival (HR = 2.49, 95% CI = 1.63-3.80) in human cancers. Elevated LINC00665 expression was also correlated with more advanced clinical stage, earlier lymph node metastasis, lower tumor differentiation, earlier distant metastasis and larger tumor size.

CONCLUSION

LINC00665 expression was critically related to the cancer prognosis, which has important prognostic implications for clinical prediction.