The Mechanism Of Circ-PKD2 Regulating Cisplatin Sensitivity Of Oral Squamous Cell Carcinoma Through Autophagy

Objective: Cisplatin(CDDP),as a first-line chemotherapy agent for oral squamous cell carcinoma(OSCC),has largely weakened its efficacy due to drug resistance and reduced sensitivity during treatment.As a tumor suppressor gene,circ-PKD2 plays a role in the proliferation,migration,and invasion of oral squamous cell carcinoma(OSCC),but its role in cisplatin sensitivity has not been clarified.This study will investigate whether circ-PKD2 is involved in the regulation of oral squamous cell carcinoma sensitivity to cisplatin and its possible mechanism,in order to provide a new idea for clinical treatment.Methods: 1.The inhibitory rate of cisplatin on OSCC cells was detected by CCK-8 with gradient dilution of cisplatin;2.The expression of circ-PKD2 in SCC-15 and CAL-27 cell lines was detected by PCR between the cisplatin treated group and the control group;3.Under the treatment of cisplatin and overexpression of circ-PKD2,the number of autophagosomes in SCC-15 and CAL-27 cells was detected by transmission electron microscopy(TEM),and the expression of autophagy-related proteins P62 and LC3 B was detected by Western blot;4.Circ-PKD2 overexpression plasmid was used to detect changes in IC50;5.The downstream miRNA of circ-PKD2 was predicted by bioinformatics,and verified by PCR and dual luciferase reports;6.The effects of transfecting miR-646 mimics or miR-646 mimics+circ-PKD2 on the expression of autophagy related proteins P62 and LC3 b were detected by Western Blot;7.Circ-PKD2 was co-transfected with miR-646 mimics,and changes in IC50 were detected by CCK-8.Results: 1.The IC50 of cisplatin on SCC-15 and CAL-27 cell lines was 8.56±0.43μg/m L and 12.12±0.42μg/m L,respectively;2.The expression of circ-PKD2 in SCC-15 and CAL-27 cell lines treated with cisplatin was more than twice that in the untreated group;3.Under the action of cisplatin,overexpression of circ-PKD2 increased the number of autophagosome,at the same time autophagy related proteins LC3 Ⅱ / Ⅰ expression was increased,P62 expression was decreased;4.Compared with the control group,circ-PKD2 overexpression reduced the IC50 of OSCC with cisplatin,while the addition of autophagy inhibitors reversed this phenomenon;5.There were complementary base binding regions between miR-646 and circ-PKD2;6.The co-transfection of miR-646 mimics and circPKD2 reversed the reduction of autophagy induced by miR-646;7.As the downstream of circ-PKD2,miR-646 enhanced the IC50 of OSCC cells.Conclusion: 1.Circ-PKD2 enhanced the sensitivity of OSCC to cisplatin by sponge absorption of miR-646.2.Autophagy was involved in the regulation of cisplatin sensitivity of circ-PKD2 to OSCC.