Circ_0000467 regulates proliferation, migration, invasion, and apoptosis in gastric cancer by targeting the miR-622/ROCK2 axis.

BACKGROUND: Gastric cancer (GC) ranks fourth as a cause of cancer-induced mortality worldwide. Recently, some studies have demonstrated that circular RNAs (circRNAs) play vital roles in human cancers, including GC. METHODS: The expression levels of circ_0000467, microRNA-622 (miR-622), and Rho-associated coiled-coil-containing protein kinase2 (ROCK2) were determined by RT-qPCR assay. The protein expression was quantified by western blot assay. The interaction relationship between miR-622 and circ_0000467 or ROCK2 was confirmed by dual-luciferase reporter assay and RIP assay. The biological behaviors of GC cells including proliferation, apoptosis, migration, and invasion were determined by EdU assay, colony-forming assay, flow cytometry, and transwell assay. The effects of circ_0000467 silencing in vivo were assessed by a xenograft experiment in nude mice. RESULTS: MiR-622 was downregulated and ROCK2 was upregulated in GC tissues and cells. Loss-of-function experiment revealed that overexpression of miR-622 decreased proliferation, migration, and invasion while it increased apoptosis in GC cells. Furthermore, ROCK2 was a functional target of miR-622, and upregulation of ROCK2 abolished miR-622-induced effects on GC cells. What's more, circ_0000467 was upregulated in GC, and inhibition of miR-622 reversed silencing of circ_0000467-caused effects on GC cells, suggesting that miR-622 was a target of circ_0000467. The suppression of circ_0000467 was able to slow the tumor growth in vivo. CONCLUSION: Mechanistically, circ_0000467 functioned as an oncogenic regulator in GC by specifically binding to miR-622 to upregulate ROCK2, which might be novel diagnostic markers for GC.

Anticancer and antibacterial flavonoids from the callus of Ampelopsis grossedentata; a new weapon to mitigate the proliferation of cancer cells and bacteria.

A new flavonoid angelioue (1) together with five known compounds cuminatanol (2), myricetin (3), epigallocatechin (4), taxifolin (5) and dihydromyricetin (6) was isolated from the callus extract of Ampelopsis grossedentata (Hand.-Mazz.) W. T. Wang and the structures were elucidated based on their detailed spectroscopic data. Among the compounds, the new compound angelioue (1) displayed significant antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) with the MIC value of 6.68 µg mL-1 and MBC value of 53.42 µg mL-1; in contrast the other compounds showed moderate to no antibacterial activity. In addition, known dihydromyricetin (6) exhibited potent cytotoxic activities against mouse breast cancer cells (4T1), human lung adenocarcinoma (A549) and human non-small cell lung cancer (NCI-H1975) tumor cell lines with GI50 values of 17.47, 18.91 and 20.50 µM mL-1, respectively. The compounds 1-5 exhibited low micro-molar inhibitory activities. Moreover, the structure-activity relationships of the most active compounds for antibacterial and cytotoxic activities are discussed. The present findings clearly suggest that the A. grossedentata callus is a good source of bioactive compounds.

Sodium Selenite Accentuates the Therapeutic Effect of Adriamycin Prodrug (PADM) against Gastric Cancer.

Selenium has remained a controversial character in cancer research. While its antitumor effects have been widely demonstrated, further evidence is required to establish it as a robust treatment regime. Sodium selenite (SS), an inorganic selenium, reportedly affected the proliferation and redifferentiation of gastric cancer cells, but whether it could act as a complement to conventional chemotherapeutic drugs for combination therapy is uncertain. Herein, SGC-7901 and MGC-803 gastric cancer cells were treated with PADM (Ac-Phe-Lys-PABC-ADM), a prodrug of doxorubicin/adriamycin (ADM), and the combined antitumor effects of the two drugs were evaluated. Characterization after treatment revealed that although PADM exhibited antitumor effects individually by inhibiting the proliferation and migration of gastric cancer cells and inducing apoptosis, the addition of SS significantly amplified these effects. Furthermore, gastric cancer cell apoptosis triggered by the combined treatment of SS and PADM may involve the participation of mitochondrial apoptosis, as evidenced by the changes in mitochondrial morphology and occurrence of mitochondrial fission. Collectively, SS could be a strong complementary drug that accentuates the therapeutic potential of PADM in gastric cancer treatment and management, and its significance could contribute to unique and innovative anticancer strategies.