morin and Tongue-Neoplasms

Morin is a naturally occurring bioflavonoid originally isolated from members of the Moraceae family of flowering plants and it possesses antitumor activity in various human cancer cells. The present study explored the antitumor effects of morin in tongue squamous cell carcinoma (TSCC) cells in vitro and investigated the underlying molecular events. A TSCC cell line was treated with different doses of morin for up to 48 h. Analyses of cell viability, using Cell Counting Kit‑8 (CCK‑8), EdU incorporation, colony formation, flow cytometric analysis of cell cycle distribution and apoptosis, wound healing assay, western blot analysis and qRT‑PCR assays, were then performed. The data revealed that morin treatment reduced Cal27 cell proliferation and reduced the migration capacity of tumor cells in a dose‑dependent manner. Morin treatment also significantly upregulated mammalian sterile 20‑like 1 (MST1) and MOB kinase activator 1 (MOB1) phosphorylation in CAL27 cells, but suppressed nuclear translocation of yes‑associated protein (YAP) through the induction of YAP phosphorylation in Cal27 cells. Moreover, the expression of YAP‑targeting genes, such as CTGF, CYR61 and ANKRD, was downregulated in morin‑treated TSCC cells, indicating that morin was able to activate the Hippo signaling pathway to inhibit YAP nuclear translocation and YAP‑related transcriptional activity in TSCC cells. In conclusion, the data from the present study demonstrated that morin produces anti‑TSCC activity in vitro through activation of the Hippo signaling pathway and the downstream suppression of YAP activity in TSCC cells. Future studies should assess the clinical antitumor effects of morin.

Topics: Antineoplastic Agents, Phytogenic; Apoptosis; Carcinoma, Squamous Cell; Cell Cycle Proteins; Cell Line, Tumor; Cell Movement; Cell Nucleus; Cell Proliferation; Cell Survival; Down-Regulation; Drug Screening Assays, Antitumor; Flavonoids; Head and Neck Neoplasms; Hippo Signaling Pathway; Humans; Moraceae; Nuclear Proteins; Plant Extracts; Protein Serine-Threonine Kinases; Signal Transduction; Squamous Cell Carcinoma of Head and Neck; Tongue Neoplasms; Transcription Factors; Up-Regulation

The modifying effects of dietary exposure of the flavonoid morin on 4-nitroquinoline 1-oxide (4-NQO)-induced tongue tumorigenesis, the activities of phase II detoxifying enzymes glutathione S-transferase (GST) and quinone reductase (QR) in liver and tongue, and cell proliferation activity in tongue were investigated in male F344 rats. At 7 weeks of age, all animals except those treated with morin alone and control group were given 4-NQO (20 ppm) in drinking water for 8 weeks to induce oral neoplasms. Starting 7 days before 4-NQO exposure, experimental groups were fed experimental diets containing morin (100 and 500 ppm) for 10 weeks ("initiation feeding"). Starting 1 week after the cessation of exposure to 4-NQO, other experimental groups given 4-NQO and a basal diet were given experimental diets for 22 weeks ("post-initiation feeding"). At week 32 week, "initiation feeding" of morin caused a significant reduction in the incidence of tongue carcinoma (by 44-100%). "Post-initiation feeding" with morin also significantly decreased the frequency of tongue carcinoma (by 44%). Morin feeding elevated liver GST and QR activities and GST activity in the anterior portion of tongue. Feeding with morin significantly lowered QR activity of the posterior part of the tongue. Dietary exposure to morin significantly decreased the proliferating cell nuclear antigen-positive index in the posterior portion. Also, morin feeding lowered tongue polyamine levels, especially in the "post-initiation feeding" group. Our results indicate that morin acts as a chemopreventive agent against tongue carcinogenesis induced by 4-NQO through modification of detoxifying enzyme activities and/or cell proliferation activities.

Topics: 4-Nitroquinoline-1-oxide; Animals; Anticarcinogenic Agents; Biogenic Polyamines; Diet; Flavonoids; Glutathione Transferase; Male; NAD(P)H Dehydrogenase (Quinone); Precancerous Conditions; Proliferating Cell Nuclear Antigen; Rats; Rats, Inbred F344; Tongue Neoplasms