Involvement of circRNA Regulators MBNL1 and QKI in the Progression of Esophageal Squamous Cell Carcinoma.

OBJECTIVES: To investigate the role of circRNA regulators MBNL1 and QKI in the progression of esophageal squamous cell carcinoma. BACKGROUND: MBNL1 and QKI are pivotal regulators of pre-mRNA alternative splicing, crucial for controlling circRNA production - an emerging biomarker and functional regulator of tumor progression. Despite their recognized roles, their involvement in ESCC progression remains unexplored. METHODS: The expression levels of MBNL1 and QKI were examined in 28 tissue pairs from ESCC and adjacent normal tissues using data from the GEO database. Additionally, a total of 151 ESCC tissue samples, from stage T1 to T4, consisting of 13, 43, 87, and 8 cases per stage, respectively, were utilized for immunohistochemical (IHC) analysis. RNA sequencing was utilized to examine the expression profiles of circRNAs, lncRNAs, and mRNAs across 3 normal tissues, 3 ESCC tissues, and 3 pairs of KYSE150 cells in both wildtype (WT) and those with MBNL1 or QKI knockouts. Transwell, colony formation, and subcutaneous tumorigenesis assays assessed the impact of MBNL1 or QKI knockout on ESCC cell migration, invasion, and proliferation. RESULTS: ESCC onset significantly altered MBNL1 and QKI expression levels, influencing diverse RNA species. Elevated MBNL1 or QKI expression correlated with patient age or tumor invasion depth, respectively. MBNL1 or QKI knockout markedly enhanced cancer cell migration, invasion, proliferation, and tumor growth. Moreover, the absence of either MBNL1 or QKI modulated the expression profiles of multiple circRNAs, causing extensive downstream alterations in the expression of numerous lncRNAs and mRNAs. While the functions of circRNA and lncRNA among the top 20 differentially expressed genes remain unclear, mRNAs like SLCO4C1, TMPRSS15, and MAGEB2 have reported associations with tumor progression. CONCLUSIONS: This study underscores the tumor-suppressive roles of MBNL1 and QKI in ESCC, proposing them as potential biomarkers and therapeutic targets for ESCC diagnosis and treatment.

Heterogeneity and prognosis of programmed cell death-ligand 1 expression in the circulating tumor cells of non-small cell lung cancer.

Due to tumor heterogeneity, the consistency of programmed cell death-ligand 1 (PD-L1) expression between circulating tumor cells (CTCs) and tissue is controversial. This study aimed to establish a method for detecting CTC PD-L1 expression and exploring the impact of the same on the prognosis of lung cancer. In 32 patients with non-small cell lung cancer, lung cancer cells in the blood were enriched using CD326 immunomagnetic beads. Goat anti-mouse polyclonal CD326 antibody stained the epithelial lung cancer cells and anti-PD-L1 antibody was used to detect the expression of CTC PD-L1. The DAKO Link 48 automatic staining device detected the expression in lung cancer tissue. The consistency of PD-L1 expression was analyzed in lung cancer tissue and CTCs. The effect of plasma interferon gamma, tumor necrosis factor alpha, and interleukin-2 on PD-L1 expression and prognosis was analyzed. The number of CTCs detected in patients was 1-36, with a median of 2. There was no significant difference in PD-L1 expression fractions between CTCs and paired tumor tissue (p>0.05). The correlation coefficient was 0.20. Regardless of lung cancer tissue or CTCs, there was no statistically significant difference in the blood cytokine levels between the two groups with positive or negative PD-L1 expression (p>0.05). There was no correlation between CTCs and PD-L1 in 23 untreated patients. The expression of PD-L1 in CTCs and lung cancer tissue is heterogeneous and unaffected by the peripheral cytokines' levels. PD-L1 expression has no correlation between CTCs and tissues and is not related to prognosis.

Down-regulation of long non-coding RNA LET is associated with poor prognosis in gastric cancer.

INTRODUCTION: Long non-coding RNAs (lncRNAs) have emerged recently as major players in tumor biology and may be used for cancer diagnosis, prognosis, and potential therapeutic targets. Although down-regulation of lncRNA LET in several cancers has been studied, its role in gastric cancer remains unknown. The aim of our study was to investigate the expression, and clinical significance of lncRNA LET in gastric cancer. METHODS: The expression of lncRNA LET was detected by quantitative real-time PCR (qRT-PCR) in pairs of tumor tissues and adjacent non-tumor tissues of 93 gastric cancer patients. Then, we analyzed the potential relationship between lncRNA LET expression levels in tumor tissues and clinicopathological features of gastric cancer, and clinical outcome. RESULTS: We found that lncRNA LET expression was markedly down-regulated in tumor tissues compared with adjacent non-tumor tissues, and associated with depth of invasion, lymph node metastasis, distant metastasis, and TNM stage. Kaplan-Meier analysis showed that patients with low lncRNA LET expression had a poor overall survival than those with high lncRNA LET expression. Moreover, univariate and multivariate analyses showed that low lncRNA LET expression was an independent poor prognostic factor for gastric cancer patients. CONCLUSIONS: Our data provided the first evidence that lncRNA LET might be a novel prognostic indicator in gastric cancer and might be a potential target for diagnosis and gene therapy.