ABSTRACT
This study aimed to evaluate the therapeutic potential of inhibiting protein arginine methyltransferase 5(PRMT5)in cisplatin-induced hearing loss.The effects of PRMT5 inhibition on cisplatin-induced auditory injury were determined using immunohistochemistry,apoptosis assays,and auditory brainstem response.The mechanism of PRMT5 inhibition on hair cell survival was assessed using RNA-seq and Cleavage Under Targets and Tagment-quantitative polymerase chain reaction(CUT&Tag-qPCR)analyses in the HEI-OC1 cell line.Pharmacological inhibition of PRMT5 significantly alleviated cisplatin-induced damage to hair cells and spiral ganglion neurons in the cochlea and decreased apoptosis by protecting mitochondrial function and preventing the accumulation of reactive oxygen species.CUT&Tag-qPCR analysis demonstrated that inhibition of PRMT5 in HEI-OC1 cells reduced the accumulation of H4R3me2s/H3R8me2s marks at the promoter region of the Pik3ca gene,thus activating the expression of Pik3ca.These findings suggest that PRMT5 inhibitors have strong potential as agents against cisplatin-induced ototoxicity and can lay the foundation for further research on treatment strategies of hearing loss.
ABSTRACT
Objective Protein arginine methyltransferase 5 (PRMT5),a member of the histone arginine methylation transferase family,is involved in a wide range of biological regulation through ei-ther epigenetic or posttranslational methylation modifications. The pur-pose of the present study was to investigate the effects of PRMT5 on cell proliferation of ovarian cancer cell HO8910. Methods Cell lines HO8910 with PRMT5 overexpression were obtained by transi-ent transfection,which were divided into three groups in the experiment: blank control group (wild-type cell line HO8910),negative control group (HO8910 cells were transfected with pCMV-myc plasmid),and experimental group (HO8910 cells were transfected with pCMV-myc-PRMT5 plasmid). Western blot was used to detect the expression of myc protein,and qRT-PCR was used to detect the ex-pression of PRMT5 mRNA. Cell lines HO8910 with inducible stable knockdown of PRMT5 were established by shRNA interference method,which were divided into four groups: pLKO control group (infected by empty vector lentivirus),pLKO+Dox (100ng/mL) group,shPRMT5 group (infected by PRMT5shRNA lentivirus) and shPRMT5+Dox (100 ng/mL) group. Western blot and qRT-PCR were used to detect the expression of PRMT5 protein and mRNA levels. Dox-induced PRMT5 knockdown was detected by increasing Dox concentration,which includes four groups,Dox 0ng/mL group,Dox 1ng/mL group,Dox 10ng/mL group,Dox 100ng/mL group,and each group was treated for 48 hours. Western blot and qRT-PCR were used to detect the PRMT5 protein and mRNA expression. Colony formation assay,EdU assay,and CCK-8 assay were used to test cells proliferation. The experiment was conducted in two large groups each with two subgroups: PRMT5 knockdown group (Dox-group,Dox+ group),PRMT5 overexpression group (pCMV-myc group,pCMV-myc-PRMT5 group). Western blot was used to detect the effects of PRMT5 expression on proliferation-related proteins. The experiment was conducted in two large groups,PRMT5 knockdown group with four subgroups : Dox 0ng/mL group,Dox 1ng/mL group,Dox 10ng/mL group and Dox 100ng/mL group,and PRMT5 overexpression group with two subgroups (pCMV-myc group and pCMV-myc-PRMT5 group). Results Western blot results showed that the expression of myc was detected in the experimental group in which HO8910 cells were transfected with pCMV-myc-PRMT5,and the expression of PRMT5 mRNA was significantly higher in the experimental group than those in the blank control group and the negative control group (P<0.001) . Western blot and qRT-PCR showed that PRMT5 protein (0.32±0.25) and mRNA expression levels in shPRMT5+Dox group were significantly lower than those of shPRMT5 group (0.89±0.18) (P<0.05). Western blot and qRT-PCR confirmed that PRMT5 protein (0.21±0.24) and mRNA expres-sion in Dox 10ng/mL group and Dox 100ng/mL group (0.08±0.15) were significantly downregulated compared to Dox 0ng/mL group (1.11±0.15) (P<0.05). Colony formation experiments,EdU experiments,and CCK-8 experiments confirmed that the proliferative ca-pacity of cells in Dox+group was lower than that of Dox-group in PRMT5 knockdown group(P<0.05); while in PRMT5 overexpression group,the proliferative capacity of pCMV-myc-PRMT5 group was significantly higher than that of the pCMV-myc group (P<0.05). Western blot results showed that the protein expression of Cyclin D1 was significantly lower in Dox 100 ng/mL group (0.17±0.06) than that in Dox 0 ng/mL group (1.18±0.18) (P<0.05) and the expression of P21 was significantly increased in PRMT5 knockdown group (P<0.05). In the PRMT5 overexpression group,the protein expression of Cyclin D1 in pCMV-myc-PRMT5 group (3.48± 0.22) was higher than that in pCMV-myc group (0.88±0.15) (P<0.05),while the protein expression of P21 (0.08±0.17) were significantly lower than that of pCMV-myc group (4.12±0.10) (P<0.05). Conclusion PRMT5 plays an important role in the proliferation of ovarian cancer cells. Down-regulation of PRMT5 can inhibit cell proliferation and up-regulation of PRMT5 can pro-mote cell proliferation.
ABSTRACT
Objective:To investigate the expression of protein arginine methyltransferase 5 (PRMT5)in the gastric cancer tissue,and to explore the relationship between the PRMT5 expression and the occurrence and the clinicopathologic characteristics of gastric cancer, and to find a new treatment target for gastric cancer.Methods:Forty-three cases of gastric cancer tissue and 15 cases of adjacent normal gastric tissue were used as gastric cancer group and control group,respectively.The immunohistochemical staining was used to detect the expression of PRMT5 in the specimens.Results:Compared with control group (13.3%),the expression rate of PRMT5 in gastric cancer group (72.1%)was significantly increased (P 0.05).Conclusion:High expression of PRMT5 may play an important role in the occurrence and development of gastric cancer.