Absence of REV3L promotes p53-regulated cancer cell metabolism in cisplatin-treated lung carcinoma cells

Emerging role of competing endogenous RNA in lung cancer drug resistance

Lung cancer remains one of the most common malignant cancers worldwide, and its survival rate is extremely low. Chemotherapy, the mainstay of lung cancer treatment, is not as effective as it could be due to the development of cellular resistance. The molecular mechanisms of drug resistance in lung cancer remain to be elucidated. Accumulating evidence suggests that ceRNAs are involved in various carcinogenesis and development. CeRNA is a transcript that regulates each other through competition with miRNA. However, the relationship between ceRNAs and chemoresistance in lung cancer remains unclear. In this narrative review, we provided a summary of treatment approaches that focus on ceRNA networks to overcome drug resistance.

Circ_0023984 Facilitates Esophageal Squamous Cell Carcinoma Progression by Regulating miR-433-3p/REV3L Axis

BACKGROUND

It has been revealed that circular RNAs (circRNAs) play an important role in regulating the malignant phenotype of tumor cells, thus involving in the progression of malignancies. However, the role of circ_0023984 in esophageal squamous cell carcinoma (ESCC) remains largely unclear.

METHODS

The quantitative real-time polymerase chain reaction and Western blot assays were used to detect the expression of circ_0023984, microRNA (miR)-443-3p, and protein reversionless 3-like (REV3L). In vitro and in vivo assays were performed using cell counting kit-8, colony formation, transwell, wound healing, flow cytometry, and xenograft assays. The interaction miR-433-3p and circ_0023984 or REV3L was confirmed by dual-luciferase reporter, pull-down or RIP assays.

RESULTS

Circ_0023984 was highly expressed in ESCC tissues and cells, knockdown of circ_0023984 suppressed cancer cell proliferation, migration, invasion, and promoted cell apoptosis in vitro. Mechanistic analysis confirmed that circ_0023984 functioned as a sponge for miR-433-3p to positively regulate the expression of REV3L that was verified to be a target of miR-433-3p. Circ_0023984 knockdown repressed the tumorigenesis of ESCC cells via targeting miR-433-3p. Additionally, miR-433-3p performed anti-proliferative, anti-migratory, and anti-invasive abilities in ESCC cells, which were reversed by REV3L overexpression. Pre-clinically, silencing of circ_0023984 suppresses the tumorigenesis and growth of xenografts in nude mice.

CONCLUSION

Circ_0023984 exerted an oncogenic role in ESCC tumorigenesis and aggressiveness through promoting cell growth, migration, and invasion via miR-433-3p/REV3L axis.

FLIM as a Promising Tool for Cancer Diagnosis and Treatment Monitoring

Fluorescence lifetime imaging microscopy (FLIM) has been rapidly developed over the past 30 years and widely applied in biomedical engineering. Recent progress in fluorophore-dyed probe design has widened the application prospects of fluorescence. Because fluorescence lifetime is sensitive to microenvironments and molecule alterations, FLIM is promising for the detection of pathological conditions. Current cancer-related FLIM applications can be divided into three main categories: (i) FLIM with autofluorescence molecules in or out of a cell, especially with reduced form of nicotinamide adenine dinucleotide, and flavin adenine dinucleotide for cellular metabolism research; (ii) FLIM with Förster resonance energy transfer for monitoring protein interactions; and (iii) FLIM with fluorophore-dyed probes for specific aberration detection. Advancements in nanomaterial production and efficient calculation systems, as well as novel cancer biomarker discoveries, have promoted FLIM optimization, offering more opportunities for medical research and applications to cancer diagnosis and treatment monitoring. This review summarizes cutting-edge researches from 2015 to 2020 on cancer-related FLIM applications and the potential of FLIM for future cancer diagnosis methods and anti-cancer therapy development. We also highlight current challenges and provide perspectives for further investigation.

Circular RNA PRMT5 confers cisplatin-resistance via miR-4458/REV3L axis in non-small-cell lung cancer

Multifactor and multistep processes were elucidated to participate in the progression of non-small-cell lung cancer (NSCLC). Circular RNA 0031250 (circ-PRMT5) was a vital factor in NSCLC. However, the role of circ-PRMT5 in cisplatin (DDP)-resistance needed to be further highlighted. Expression profiles of circ-PRMT5, microRNA (miR)-4458, and EV3-like DNA-directed polymerase ζ catalytic subunit (REV3L) were detected using quantitative real-time polymerase chain reaction. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry, and transwell assays were performed to determine the half-maximal inhibitory concentration of DDP, cell viability, apoptosis, and invasion in vitro. Besides, the protein levels of REV3L and indicated proteins were examined by adopting western blot. Dual-luciferase reporter assay was performed to analyze the interaction between miR-4458 and circ-PRMT5 or REV3L. The functional role of circ-PRMT5 was explored using a xenograft tumor model. Levels of circ-PRMT5 and REV3L were markedly increased, while miR-4458 was downregulated in resistant tissues and cells. Knockdown of circ-PRMT5 enhanced cell apoptosis, DDP-sensitivity, and declined metastasis in NSCLC with DDP resistance. Besides, miR-4458 inhibition or REV3L upregulation could revert circ-PRMT5 absence-mediated effect on DDP-sensitivity in vitro. Mechanically, circ-PRMT5 was a sponge of miR-4458 to regulate REV3L. Importantly, circ-PRMT5 silencing could interact with DDP treatment expedite the decrease of tumor growth in vivo. Circ-PRMT5 promoted DDP resistance via REV3L by sponging miR-4458 in NSCLC, thus providing a novel therapeutic strategy for patients with NSCLC.

HMGB1-containing nucleosome mediates chemotherapy-induced metastasis of human lung cancer

While chemotherapy is an important and widely used therapeutic for cancer, it may facilitate cancer metastasis. Herein, we report that human lung cancer cells exert higher invasion and metastasis after chemotherapy. In a human lung cancer xenograft model, chemotherapy promotes the cancer invasion and metastasis in HMGB1-dependent manner. Further studies identify HMGB1-containing nucleosome from chemotherapy-induced apoptotic cancer cells as an effective factor. Such nucleosome functions through TLR4 and TLR9 to drive cancer invasion and metastasis. In lung cancer patients, circulating HMGB1-containing nucleosome is higher in those under chemotherapy, predicting poorly cancer cell differentiation state, enhanced cancer invasion and advanced TNM stages. These findings provide a novel mechanism by which the tumor metastasis is propagated in lung cancer patients, especially in those under chemotherapy, and a clue for developing therapeutic strategies against chemotherapy-induced metastasis.