ABSTRACT
Background: In Dayao County, Chuxiong Yi Autonomous Prefecture, Yunnan Province, Southwest China, 5% of the surface is scattered with blue asbestos, which has a high incidence of pleural mesothelioma (PMe). Simian virus 40 (SV40) is a small circular double-stranded DNA polyomavirus that can cause malignant transformation of normal cells of various human and animal tissue types and promote tumor growth. In this study, we investigate whether oncogenic SV40 is associated with the occurrence of PMe in the crocidolite-contaminated area of Dayao County, Yunnan Province, Southwest China. Methods: Tumor tissues from 51 patients with PMe (40 of whom had a history of asbestos exposure) and pleural tissues from 12 non-PMe patients (including diseases such as pulmonary maculopathy and pulmonary tuberculosis) were collected. Three pairs of low-contamination risk primers (SVINT, SVfor2, and SVTA1) were used to detect the gene fragment of SV40 large T antigen (T-Ag) by polymerase chain reaction (PCR). The presence of SV40 T-Ag in PMe tumor tissues and PMe cell lines was detected by Western blotting and immunohistochemical staining with SV40-related antibodies (PAb 101 and PAb 416). Results: PCR, Western blotting, and immunohistochemical staining results showed that the Met5A cell line was positive for SV40 and contained the SV40 T-Ag gene and protein. In contrast, the various PMe cell lines NCI-H28, NCI-H2052, and NCI-H2452 were negative for SV40. PCR was negative for all three sets of low-contamination risk primers in 12 non-PMe tissues and 51 PMe tissues. SV40 T-Ag was not detected in 12 non-PMe tissues or 51 PMe tissues by immunohistochemical staining. Conclusion: Our data suggest that the occurrence of PMe in the crocidolite-contaminated area of Yunnan Province may not be related to SV40 infection and that crocidolite exposure may be the main cause of PMe. The Clinical Trial Registration number: 2020-YXLL20.
Subject(s)
Asbestos, Crocidolite , Pleural Neoplasms , Simian virus 40 , Humans , Simian virus 40/genetics , China/epidemiology , Male , Female , Middle Aged , Aged , Pleural Neoplasms/epidemiology , Pleural Neoplasms/virology , Pleural Neoplasms/genetics , Mesothelioma/virology , Mesothelioma/epidemiology , Mesothelioma/genetics , Polyomavirus Infections/epidemiology , Tumor Virus Infections/epidemiology , Cell Line, Tumor , Mesothelioma, Malignant/genetics , Lung Neoplasms/virology , Lung Neoplasms/genetics , Lung Neoplasms/epidemiology , AdultABSTRACT
Cyclin-dependent kinase (CDK) family members have been considered as attractive therapeutic targets for cancer. In this study, we aim to investigate the anticancer effects of a selective CDK7 inhibitor, BS-181, in gastric cancer (GC) cell line. Human GC cells (BGC823) were cultured with or without BS-181 at different concentrations for 24-72 hours. BS-181 significantly reduced the activity of CDK7 with downregulation of cyclin D1 and XIAP in GC cells. Treatment with BS-181 induced cell cycle arrest and apoptosis. The expression of Bax and caspase-3 was significantly increased, while Bcl-2 expression was decreased in cells treated with BS-181. In addition, the inhibition of CDK7 with BS-181 resulted in reduced rates of proliferation, migration, and invasion of gastric cells. Those results demonstrated the anticancer activities of selective CDK7 inhibitor BS-181 in BGC823 cells, suggesting that CDK7 may serve as a novel therapeutic target or the treatment of GC.
Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Cyclin-Dependent Kinases/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Stomach Neoplasms/drug therapy , Stomach Neoplasms/pathology , Animals , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Cell Survival/drug effects , Cyclin-Dependent Kinases/metabolism , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/pathology , Protein Kinase Inhibitors/chemistry , Pyrazoles/chemistry , Pyrimidines/chemistry , Structure-Activity Relationship , Tumor Cells, Cultured , Cyclin-Dependent Kinase-Activating KinaseABSTRACT
Triptolide has been reported to exhibit antitumor effects in several cancers. This study investigates the mechanism by which triptolide induces apoptosis of gastric cancer cells. Gastric biopsies were collected for histological evaluation and detection of murine double minute 2 (MDM2) expression. Gastric cancer cells were cultured and treated with different concentrations of triptolide at indicated time points. The expression of MDM2, p53 protein, and target proteins including p21, PUMA, and X-linked inhibitor of apoptosis protein (XIAP) was detected. Apoptosis of cells treated with or without triptolide was evaluated. Our results showed that MDM2 protein was overexpressed in gastric cancer (p < 0.01, resp.). Triptolide induced significant apoptosis of gastric cancer cells in a dose- and time-dependent manner (p < 0.05). In addition, treatment with triptolide strongly inhibited the overexpression of MDM2 in gastric cancer cells, and this MDM2 inhibition led to increased levels of p53 protein and inhibition of XIAP (p < 0.05). However, triptolide failed to increase the expression of p53 target protein p21 and PUMA (p > 0.05). In conclusion, triptolide may induce apoptosis of gastric cancer cells via the inhibition of MDM2 overexpression in a p53-independent manner.