Retracted Article: Long non-coding RNA GACAT1 alleviates doxorubicin and vincristine resistance through a PTEN/AKT/mTOR/S6K1 regulatory pathway in gastric cancer

Fangchinoline derivatives inhibits PI3K signaling in vitro and in vivo in non-small cell lung cancer

Fangchinoline (Fan) are extracted from the traditional Chinese medicine Stephania tetrandra S., which is a bis-benzyl isoquinoline alkaloids with anti-tumor activity. Therefore, 25 novel Fan derivatives have been synthesized and evaluated for their anti-cancer activity. In CCK-8 assay, these fangchinoline derivatives displayed higher proliferation inhibitory activity on six tumor cell lines than the parental compound. Compared to the parent Fan, compound 2h presented the anticancer activity against most cancer cells, especially A549 cells, with an IC50 value of 0.26 μM, which was 36.38-fold, and 10.61-fold more active than Fan and HCPT, respectively. Encouragingly, compound 2h showed low biotoxicity to the human normal epithelial cell BEAS-2b with an IC50 value of 27.05 μM. The results indicated compound 2h remarkably inhibited the cell migration by decreasing MMP-2 and MMP-9 expression and inhibited the proliferation of A549 cells by arresting the G2/M cell cycle. Meanwhile, compound 2h could also induce A549 cell apoptosis by promoting endogenous pathways of mitochondrial regulation. In nude mice presented that the growth of tumor tissues was markedly inhibited by the consumption of compound 2h in a dose-dependent manner, and it was found that compound 2h could inhibit the mTOR/PI3K/AKT pathway in vivo. In docking analysis, high affinity interaction between 2h and PI3K was responsible for drastic kinase inhibition by the compound. To conclude, this derivative compound may be useful as a potent anti-cancer agent for treatment of NSCLC.

LncRNA GACAT1 targeting miRNA-149 regulates the molecular mechanism of proliferation, apoptosis and autophagy of oral squamous cell carcinoma cells

To explore the effects of lncRNA GACAT1/miR-149 molecular axis on the proliferation, apoptosis, migration and autophagy of oral squamous cell carcinoma (OSCC) cells, and to explore its molecular mechanism. The expressions of lncRNA GACAT1 and miR-149 in tissues and cell lines of patients with OSCC were detected by qRT-PCR. Si-control, GACAT1-siRNA, inhibitor NC and miR-149 inhibitors were transfected into OSCC cells separately or in combination with Lipofectamine 2000. The binding sites between lncRNA GACAT1 and miR-149 were predicted using the miRanda website, and the targeting relationship was verified by dual-luciferase assay. The expression of lncRNA XIST and miR-149 was detected by qRT-PCR. CCK-8 assay was used to detect cell activity. Cell cycle distribution and apoptosis were detected by flow cytometry. Cell migration ability was detected by Transwell assay. The expression of migration and autophagy-related proteins was detected by western blot. LncRNA GACAT1 was highly expressed in cancer tissues and cell lines of OSCC patients (P < 0.01), while miR-149 was low expressed (P < 0.01). LncRNA GACAT1 binds to miR-149 targeting. The down-regulation of lncRNA GACAT1 inhibited the proliferation and migration of OSCC cells and promoted apoptosis and autophagy (P < 0.01). The transfection of miR-149 inhibitor had the opposite effect. Knockdown of lncRNA GACAT1 and transfection with miR-149 inhibitor reversed the effect of GACAT1 silencing on OSCC cells. Inhibition of lncRNA GACAT1 can inhibit the proliferation and migration of OSCC cells, promote apoptosis and autophagy, and the mechanism may be related to the targeting of miR-149.

The role of miRNAs and lncRNAs in conferring resistance to doxorubicin

Doxorubicin is a chemotherapeutic agent that inhibits topoisomerase II, intercalates within DNA base pairs and results in oxidative DNA damage, thus inducing cell apoptosis. Although it is effective in the treatment of a wide range of human cancers, the emergence of resistance to this drug can increase tumour growth and impact patients' survival. Numerous molecular mechanisms and signalling pathways have been identified that induce resistance to doxorubicin via stimulation of cell proliferation, cell cycle switch and preclusion of apoptosis. A number of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have also been identified that alter sensitivity to doxorubicin. Understanding the particular impact of these non-coding RNAs in conferring resistance to doxorubicin has considerable potential to improve selection of chemotherapeutic regimens for cancer patients. Moreover, modulation of expression of these transcripts is a putative strategy for combating resistance. In the current paper, the influence of miRNAs and lncRNAs in the modification of resistance to doxorubicin is discussed.

Role of Long Non-Coding RNAs in the Chemoresistance of Gastric Cancer: A Systematic Review

PURPOSE

Accumulating evidence demonstrates that long non-coding RNAs (lncRNAs) play a vital role in the chemoresistance of gastric cancer (GC). The present systematic review summarises the emerging role, potential targets or pathways and regulatory mechanisms of lncRNAs involved in chemoresistance and proposes a number of clinical implications of lncRNAs as novel therapeutic targets for GC.

METHODS

Studies on lncRNAs involved in the chemoresistance of GC published until July 2020 in the PubMed and Web of Science databases were systematically reviewed and the expression form, role in chemoresistance, targets or pathways, corresponding drugs and potential mechanisms of relevant lncRNAs were summarised in detail.

RESULTS

A total of 48 studies were included in this systematic review. Amongst these studies, 32 involved single drug resistance and 16 involved in multidrug resistance (MDR). The 48 studies collected described 38 lncRNAs in the drug-resistant cells of GC, including 33 upregulated and 5 downregulated lncRNAs. Cisplatin (DDP) was the most studied drug and lncRNA MALAT1 was the most studied lncRNA related to the chemoresistance of GC. The potential mechanisms of chemoresistance for lncRNAs in GC mainly included, amongst others, reduction of apoptosis, induction of autophagy, repair of DNA damage, promotion of epithelial-mesenchymal transition (EMT) and regulation of the related signalling pathways.

CONCLUSION

LncRNAs play a vital role in the chemoresistance of GC and are novel therapeutic targets for the disease. Detailed chemoresistance mechanisms, translational studies and clinical trials on lncRNAs in GC are urgently needed.

Effect of knockdown of long-chain noncoding RNA KCNQ1 overlapping transcript 1 on growth and cisplatin sensitivity of HGC-27 cells

BACKGROUND

Gastric cancer (GC) had become one of the malignant tumors that threaten the safety of human life. At present, the molecular mechanism of the occurrence and development of GC has not been fully elucidated. The regulatory role of long-chain noncoding RNAs in these processes has not yet been elucidated.

AIM

To investigate the effect of KCNQ1 overlapping transcript 1 (KCNQ1OT1) on the proliferation, invasion, migration, and cisplatin sensitivity of HGC-27 cells.

METHODS

HCN-27 cells transfected with KCNQ1OT1-siRNA were used as a KCNQ1OT1-siRNA group, HGC-27 cells transfected with negative control siRNA were used as an NC-siRNA group, and normally cultured cells were used as a control group. After treatment of cells in the KCNQ1OT1-siRNA group and NC-siRNA group with cisplatin, cell viability was measured by Cell Counting Kit-8 assay, and the half-maximal inhibitory concentration (IC50) was calculated. Real-time quantitative polymerase chain reaction, Transwell assay, flow cytometry, and Western blot were used to detect KCNQ1OT1 expression level, cell proliferation, invasion, and migration, cycle distribution, and the expression of E-cadherin, N-cadherin, Vimentin, P-glycoprotein (P-gp), and multidrug resistance associated protein 1 (MRP1), respectively.

RESULTS

Compared with the control group, there was no significant change in the indexes in the NC-siRNA group (P > 0.05). Compared with the control group or NC-siRNA group, the expression level of KCNQ1OT1, the percentages of cells in S phase and G2/M phase, the ability of cell proliferation, invasion, and migration, and the expression levels of N-cadherin and Vimentin in cells of the KCNQ1OT1-siRNA group were significantly reduced, while the percentage of cells in G0/G1 phase was significantly reduced (P > 0.05). Compared with the NC-siRNA group, the protein levels of P-gp and MRP1 in the KCNQ1OT1-siRNA group were significantly reduced (P < 0.05), and the IC50 was significantly reduced (P < 0.05).

CONCLUSION

KCNQ1OT1 knockdown can inhibit the proliferation, invasion, and migration of HGC-27 cells and enhance their sensitivity to cisplatin.