Circular RNA circ_0007841 participates in progression of nonsmall cell lung cancer via miR-199a-5p/SphK2 axis

Resveratrol suppresses NSCLC cell growth, invasion and migration by mediating Wnt/β-catenin pathway via downregulating SIX4 and SPHK2

Resveratrol (RSV) has been found to have a cancer-suppressing effect in a variety of cancers, including non-small cell lung cancer (NSCLC). Studies have shown that sine oculis homeobox 4 (SIX4) and sphingosine kinase 2 (SPHK2) are tumour promoters of NSCLC. However, whether RSV regulates SIX4 and SPHK2 to mediate NSCLC cell functions remains unclear. NSCLC cell functions were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry, transwell assay and wound healing assay. Protein expression levels were detected by western blot. SIX4 and SPHK2 mRNA levels in NSCLC tumour tissues were examined using quantitative real-time PCR. In addition, mice xenograft models were built to explore the impact of RSV on NSCLC tumour growth. RSV inhibited NSCLC cell proliferation, invasion and migration, while facilitated apoptosis. SIX4 and SPHK2 were up-regulated in NSCLC tissues and cells, and their expression was reduced by RSV. Knockdown of SIX4 and SPHK2 suppressed NSCLC cell growth, invasion and migration, and the regulation of RSV on NSCLC cell functions could be reversed by SIX4 and SPHK2 overexpression. RSV inactivated Wnt/β-catenin pathway via decreasing SIX4 and SPHK2 levels. In animal experiments, RSV reduced NSCLC tumour growth in vivo. RSV repressed NSCLC malignant process by decreasing SIX4 and SPHK2 levels to restrain the activity of Wnt/β-catenin pathway.

CircPDSS1 (hsa_circ_0017998) silencing induces ferroptosis in non-small-cell lung cancer cells by modulating the miR-137/SLC7A11/GPX4/GCLC axis

BACKGROUND

Circular RNAs (circRNAs) regulate the tumorigenesis of non-small-cell lung cancer (NSCLC). CircPDSS1 (hsa_circ_0017998) has been newly discovered, and its role in NSCLC remains elusive. We aimed to investigate the functional roles and downstream targets of circPDSS1 in NSCLC cells.

MATERIALS AND METHODS

Cellular viabilities were measured through the Cell Counting Kit-8 (CCK-8) assay, whereas cell death was assessed through flow cytometry. The lactate dehydrogenase activity, malondialdehyde levels, ferrous iron, and reactive oxygen species were measured using commercial assay kits. The interaction between circPDSSA/ microRNA-137 (miR-137) and miR-137/solute carrier family 7 member 11 (SLC7A11) was assayed through a dual luciferase activity assay. Finally, the mRNA and protein levels were measured using real-time reverse transcriptase-polymerase chain reaction and western blots, respectively.

RESULTS

CircPDSS1 expression was upregulated in NSCLC cells, compared with healthy lung cells. CircPDSS1 silencing suppressed the viability of NSCLC cells. Additionally, circPDSS1 knockdown induced ferroptosis rather than other types of cell death in NSCLC cells. Mechanically, circPDSS1 functions as a "sponge" to inversely control miR-137 expression, which directly targets SLC7A11. Moreover, circPDSS1 silencing causes the downregulation of glutathione peroxidase 4 (GPX4) and glutamate-cysteine ligase catalytic subunit (GCLC).

CONCLUSIONS

Targeting the circPDSS1/miR-137/SLC7A11/GPX4/GCLC axis may be a promising strategy to kill NSCLC cells.

Circ_0070934 promotes MGAT3 expression and inhibits epithelial-mesenchymal transition in bronchial epithelial cells by sponging miR-199a-5p

BACKGROUND

Circular RNA (circRNA) has the potential to serve as a crucial regulator in the progression of bronchial asthma. The objective of this investigation was to elucidate the functional dynamics of the circ_0070934/miR-199a-5p/Mannoside acetylglucosaminyltransferase 3 (MGAT3) axis in the development of asthma.

METHODS

Circ_0070934, miR-199a-5p and MGAT3 in peripheral venous blood of 38 asthmatic patients and 43 healthy controls were detected by qRT-PCR, and the expression of MGAT3 protein was examined by ELISA. The GSE148000 dataset was analyzed for differences in MGAT3. The BEAS-2B cells were transfected with circ_0070934 plasmid and small interfering RNA, miR-199a-5p mimics and inhibitors. The apoptosis level was detected by flow cytometry and MGAT3 was detected by qRT-PCR and Western blot. The expression of E-cadherin, N-cadherin, Vimentin was examined by Western blot. Interleukin-4 (IL-4) and IL-13 were used to co-stimulate BEAS-2B cells as an asthmatic airway epithelial cell model. BEAS-2B cells exposed to type 2 cytokines (IL-4 and IL-13) were treated with circ_0070934 plasmid, and the expression of E-cadherin, N-cadherin, and Vimentin was detected by Western blot. The binding relationships were verified using dual-luciferase reporter assay and miRNA pull-down assay.

RESULTS

The expression of circ_0070934 and MGAT3 in peripheral venous blood of asthmatic patients was down-regulated, and the expression of miR-199a-5p was up-regulated. And the expression of MGAT3 was reduced in sputum of asthma patients. Down-regulating the expression of circ_0070934 could promote apoptosis of BEAS-2B cells and increase epithelial-mesenchymal transition (EMT), and this effect can be partially reversed by down-regulating miR-199a-5p. Circ_0070934 could inhibit the process of epithelial mesenchymal transition induced by IL-4 and IL-13 in BEAS-2B cells. In addition, miR-199a-5p could respectively bind to circ_0070934 and MGAT3.

CONCLUSION

The findings of this study indicate that circ_0070934 may function as a competitive endogenous RNA (ceRNA) of miR-199a-5p, thereby modulating the expression of MGAT3 and impacting the process of EMT in bronchial epithelial cells. These results contribute to the establishment of a theoretical framework for advancing the prevention and treatment strategies for asthma.

The quantification of circular RNA 0007841 during induction therapy helps estimate the response and survival benefits to bortezomib-based regimen in multiple myeloma

OBJECTIVE

Circular RNA_0007841 (Circ_0007841) facilitates multiple myeloma (MM) progression and resistance of the bortezomib by experimental studies, while its clinical implication in MM patients is still unclear. This study intended to evaluate the longitudinal change and prognostic role of circ_0007841 expression in MM patients receiving bortezomib-based induction therapy.

METHODS

In this prospective study, bone marrow plasma cell (BMPC) samples were gained from 97 MM patients at diagnosis and after bortezomib-based induction therapy, and from 30 healthy controls (HCs) proposing BM donation. Then, circ_0007841 expression in BMPC samples was measured by reverse transcription-quantitative polymerase chain reaction. Additionally, MM patients were followed up for a median of 29.4 months.

RESULTS

Circ_0007841 expression was increased in MM patients compared to HCs (P < 0.001), but it was decreased after bortezomib-based induction therapy in MM patients (P < 0.001). Moreover, circ_0007841 expression at diagnosis was associated with the presence of t (4; 14) (P = 0.034), while its expression after bortezomib-based induction therapy was linked with higher revised international staging system stage (P = 0.025) in MM patients. Interestingly, circ_0007841 expression after bortezomib-based induction therapy was lower in MM patients who achieved complete remissions (P = 0.001) and overall responses (P = 0.002) compared to those who did not. Prognostically, circ_0007841 expression after bortezomib-based induction therapy (over the median vs. below the median) independently predicted shorter progression-free survival (hazard ratio (HR): 2.497, P = 0.002) and overall survival (HR: 3.107, P = 0.008) in MM patients.

CONCLUSION

Circ_0007841 quantification during induction therapy may reflect the response and survival benefits to bortezomib-based regimen in MM patients.

The role of circRNAs in regulation of drug resistance in ovarian cancer

Ovarian cancer is one of the female reproductive system tumors. Chemotherapy is used for advanced ovarian cancer patients; however, drug resistance is a pivotal cause of chemotherapeutic failure. Hence, it is critical to explore the molecular mechanisms of drug resistance of ovarian cancer cells and to ameliorate chemoresistance. Noncoding RNAs (ncRNAs) have been identified to critically participate in drug sensitivity in a variety of human cancers, including ovarian cancer. Among ncRNAs, circRNAs sponge miRNAs and prevent miRNAs from regulation of their target mRNAs. CircRNAs can interact with DNA or proteins to modulate gene expression. In this review, we briefly describe the biological functions of circRNAs in the development and progression of ovarian cancer. Moreover, we discuss the underneath regulatory molecular mechanisms of circRNAs on governing drug resistance in ovarian cancer. Furthermore, we mention the novel strategies to overcome drug resistance via targeting circRNAs in ovarian cancer. Due to that circRNAs play a key role in modulation of drug resistance in ovarian cancer, targeting circRNAs could be a novel approach for attenuation of chemoresistance in ovarian cancer.