RETRACTED ARTICLE: Reduced LINC00467 elevates microRNA-125a-3p to suppress cisplatin resistance in non-small cell lung cancer through inhibiting sirtuin 6 and inactivating the ERK1/2 signaling pathway

Olaparib increases chemosensitivity by upregulating miR-125a-3p in ovarian cancer cells

OBJECTIVE

Ovarian cancer is associated with the highest mortality rate among all malignant gynecological tumors. PolyADP-ribose polymerase (PARP) inhibitor maintenance therapy is the standard treatment strategy for this type of cancer, and olaparib is a widely used oral PARP inhibitor for tumors with BRCA mutations. The present study aimed to investigate the effects of olaparib in non-BRCA-mutated ovarian cancer and the potential mechanisms involved.

METHODS

The antitumor effect of cisplatin alone or in combination with olaparib was analyzed in an ovarian cancer subcutaneous transplantation tumor model in nude mice. Furthermore, the differences in microRNA (miRNA) expression levels were analyzed using miRNA arrays. In addition, the effects of miR-125a-3p on the proliferation of non-BRCA-mutated (A2780 and OVCAR-3) ovarian cancer cells were detected using A Cell Counting Kit-8 and changes in the cell cycle were detected using flow cytometry. Furthermore, SPiDER-βGal was used to detect expression changes in cellular senescence, and the expression of DNA damage repair proteins was detected using western blot analysis.

RESULTS

The results revealed that cisplatin plus olaparib significantly reduced tumor volume in mice subjected to subcutaneous tumor transplantation, and the expression of miR-125a-3p significantly increased with this treatment combination. The overexpression of miR-125a-3p could inhibit cell migration, invasion and induces cell cycle arrest.

CONCLUSION

On the whole, the present study demonstrates that the increased expression of miR-125a-3p induces DNA damage and senescence in ovarian cancer cells, which enhances the therapeutic sensitivity.

Long non‑coding RNAs as potential therapeutic targets in non‑small cell lung cancer (Review)

Non‑small cell lung cancer (NSCLC) is one of the most common malignancies with a high morbidity and mortality rate. Long non‑coding RNAs (lncRNAs) have been reported to be closely associated with the occurrence and progression of NSCLC. In addition, lncRNAs have been documented to participate in the development of drug resistance and radiation sensitivity in patients with NSCLC. Due to their extensive functional characterization, high tissue specificity and sex specificity, lncRNAs have been proposed to be novel biomarkers and therapeutic targets for NSCLC. Therefore, in the current review, the functional classification of lncRNAs were presented, whilst the potential roles of lncRNAs in NSCLC were also summarized. Various physiological aspects, including proliferation, invasion and drug resistance, were all discussed. It is anticipated that the present review will provide a perspective on lncRNAs as potential diagnostic molecular biomarkers and therapeutic targets for NSCLC.

MicroRNA-122a aggravates intestinal ischemia/reperfusion injury by promoting pyroptosis via targeting EGFR-NLRP3 signaling pathway

Multiple studies have confirmed the significance of microRNA (miR)-122a in disease regulation. However, its impact on ischaemia/reperfusion (I/R) injury is unknown. In this study, we propose that the promoting role of miR-122a exists in I/R injuries. Two models, including hypoxia/reoxygenation (H/R)-injured IEC-6 cells in vitro and ischemia/reperfusion (I/R)-injured C57BL/6 mice intestinal tissues in vivo, were used to verify our purpose. Applying dual-luciferase reporter assays and transfection tests, the regulatory impacts of miR-122a were examined by promoting pyroptosis on intestinal I/R injury via targeting epidermal growth factor receptor (EGFR)-NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) signaling pathway. Both H/R-injured IEC-6 cells and I/R-injured mice intestinal tissues had elevated miR-122a expression, which targeted EGFR directly. Increased miR-122a expression significantly inhibited EGFR activity, decreased EGFR mRNA and protein expression, increased NLRP3 mRNA and protein expression, and up-regulated caspase 1, N-GSDMD, ASC, IL-1β, and IL-18 protein expression to promote pyroptosis. Furthermore, in IEC-6 cells, a miR-122a inhibitor and an EGFR-overexpression plasmid significantly reduced pyroptosis and alleviated intestinal I/R injury via activating the EGFR-NLRP3 signaling pathway, showing that miR-122a is very essential for regulating intestinal I/R injury. In brief, miR-122a promotes pyroptosis by inhibiting the EGFR-NLRP3 signaling pathway, which should be evaluated as a therapeutic target for intestinal I/R injury.

The histone deacetylase SIRT6 promotes glycolysis through the HIF-1α/HK2 signaling axis and induces erlotinib resistance in non-small cell lung cancer

Erlotinib is a first-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI). Overcoming erlotinib resistance is crucial to improve the survival of advanced non-small cell lung cancer (NSCLC) patients with sensitive EGFR mutations. It is also an important clinical problem that urgently needs a solution. In this study, we explored strategies to overcome erlotinib resistance from the perspective of energy metabolism. SIRT6 is a histone deacetylase. Here, we found that high expression of SIRT6 is associated with poor prognosis of lung adenocarcinoma, especially in EGFR-mutated NSCLC patients. The next cell experiment found that SIRT6 expression increased in erlotinib-resistant cells, and SIRT6 expression was negatively correlated with the sensitivity of NSCLC to erlotinib. Inhibition of SIRT6 promoted erlotinib-induced apoptosis in erlotinib-resistant cells, and glycolysis in drug-resistant cells was also inhibited. Functional studies have shown that SIRT6 increases glycolysis through the HIF-1α/HK2 signaling axis in drug-resistant cells and inhibits the sensitivity of NSCLC cells to erlotinib. In addition, the HIF-1α blocker PX478-2HCL attenuated the glycolysis and erlotinib resistance induced by SIRT6. More importantly, we confirmed the antitumor effect of SIRT6 inhibition combined with erlotinib in NSCLC-bearing mice. Our findings indicate that the cancer metabolic pathway regulated by SIRT6 may be a new target for attenuating NSCLC erlotinib resistance and has potential as a biomarker or therapeutic target to improve outcomes in NSCLC patients.

Whole-Exome Sequencing Uncovers Specific Genetic Variation Difference Based on Different Modes of Drug Resistance in Small Cell Lung Cancer

The poor survival rate of small cell lung cancer (SCLC) is mainly related to the condition that patients with SCLC often have good responses to first-line chemotherapy initially, but later on, most of these patients relapse rapidly due to resistance to further treatment. In this study, we attempted to analyze whole-exome sequencing data based on the largest sample size to date, to develop a classifier to predict whether a patient will be chemorefractory or chemosensitive and to explicate the risk of recurrence that affects the prognosis of patients. We showed the different characteristics of somatic mutational signatures, somatic mutation genes, and distinct genome instability between chemorefractory and chemosensitive SCLC patients. Amplified mutations in the chemosensitive group inhibited the regulation of the cell cycle process, transcription factor binding, and B-cell differentiation. Analysis of deletion mutation also suggested that detection of the chromosomal-level variation might influence our treatment decisions. Higher PD-L1 expressions (based on TPS methods) were mostly present among chemosensitive patients (p = 0.026), while there were no differences in PD-L1 expressions (based on CPS methods) and CD8⁺ TILs between the two groups. According to the model determined by logistic regression, each sample was endowed with a predictive probability value (PV). The samples were divided into a high-risk group (>0.55) and a low-risk group (≤0.55), and the survival analysis showed obvious differences between the two groups. This study provides a reference basis to translate this knowledge into practice, such as formulating personalized treatment plans, which may benefit Chinese patients with SCLC.

Long Noncoding RNA LINC00467: Role in Various Human Cancers

Intricate genetic mutations promote the progression of different cancer types. Long noncoding RNAs (lncRNAs) have been widely demonstrated to participate in the genomic activities of various human cancers. Long intergenic non-coding RNA 467 (LINC00467) is an upregulated lncRNA in diverse diseases, especially in several types of cancers. Functional experiments of LINC00467 revealed that LINC00467 overexpression enhanced cell chemoresistance, proliferation, migration, and invasion in several types of cancers. Moreover, overexpressed LINC00467 was associated with a poor clinical prognosis. The present evidence suggests that LINC00467 may serve as a promising prognostic indicator and become a novel cancer therapeutic target. In this review, we introduce the biologic functions of lncRNAs and describe the molecular mechanism and clinical significance of LINC00467 in detail.