Abstract. Paclitaxel in combination with carboplatin improves survival among patients with susceptible ovarian cancers, but no strategy has been established against resistant ovarian cancers. BAG3 (Bcl-2-associated athanogene 3) is one of six BAG family proteins, which are involved in such cellular processes as proliferation, migration and apoptosis. In addition, expression of BAG3 with Mcl-1, a Bcl-2 family protein, reportedly associates with resistance to chemotherapy. Our aim in this study was to evaluate the functional role of BAG3 and Mcl-1 in ovarian cancer chemoresistance and explore possible new targets for treatment. We found that combined expression of BAG3 and Mcl-1 was significantly associated with a poor prognosis in ovarian cancer patients. In vitro, BAG3 knockdown in ES2 clear ovarian cancer cells significantly increased the efficacy of paclitaxel in combination with the Mcl-1 antagonist MIM1, with or without the Bcl-2 family antagonist ABT737. Moreover, BAG3 was found to positively regulate Mcl-1 levels by binding to and inhibiting USP9X. Our data show that BAG3 and Mcl-1 are key mediators of resistance to chemotherapy in ovarian cancer. In BAG3 knockdown ES2 clear ovarian cancer cells, combination with ABT737 and MIM1 enhanced the efficacy of paclitaxel. These results suggest that inhibiting BAG3 in addition to antiapoptotic Bcl-2 family proteins may be a useful therapeutic strategy for the treatment of chemoresistant ovarian cancers.
A diagnosis of cervical cancer during pregnancy poses difficult management and ethical problems. Survival of the patient is the foremost concern, but fetal viability and well-being must also be addressed. Radical trachelectomy (RT) has recently begun to be performed as a possible treatment modality for early stage invasive uterine cervical cancer in pregnant patients who would like to continue their pregnancy. A 32-year-old Japanese woman visited a local hospital for prenatal care, and was diagnosed with a FIGO I B1 adenocarcinoma of the uterine cervix. She had a strong desire to avoid pregnancy termination, so she was admitted to our hospital for fertility-preserving surgery. After extensive counseling, vaginal radical trachelectomy with abdominal pelvic lymphadenectomy was performed in the 16th gestational week. The excised uterine cervix and lymph nodes were pathologically negative for cancer. To maintain her pregnancy, daily vaginal disinfection with povidone iodine, bed rest, and administration of ritodrine and an ulinastatin vaginal suppository were continued until the delivery. At 34 weeks' gestation, an emergency cesarean section was performed because of sudden premature rupture of the membranes. A baby girl was born weighing 2112 g, with Apgar score of 8/9. The mother remains without evidence of recurrence at the time of this report. This is the first case of successful pregnancy and delivery in Japan after vaginal RT.
Approximately 30% of uterine corpus carcinomas are diagnosed at an advanced stage and have a poor prognosis. Our previous study indicated that BCL2-associated athanogene 3 (BAG3) enhances matrix metalloproteinase-2 (MMP2) expression and binds to MMP2 to positively regulate the process of cell invasion in ovarian cancer cells. Recently, altered miRNA expression patterns were observed in several groups of patients with endometrial cancers. One of the altered miRNAs, miR-29b, reportedly reduces tumor invasiveness by suppressing MMP2 expression. Our aim in the present study was to examine the relationships among BAG3, miR-29b and MMP2 in endometrioid adenocarcinoma cells. We found that BAG3 suppresses miR-29b expression and enhances MMP2 expression, which in turn increases cell motility and invasiveness. Moreover, restoration of miR-29b through BAG3 knockdown reduced MMP2 expression, as well as cell motility and invasiveness. Collectively, our findings indicate that BAG3 enhances MMP2 expression by suppressing miR-29b, thereby increasing the metastatic potential of endometrioid adenocarcinomas.
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