BAG3-mediated Mcl-1 stabilization contributes to drug resistance via interaction with USP9X in ovarian cancer.

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 anti-apoptotic Bcl-2 family proteins may be a useful therapeutic strategy for the treatment of chemoresistant ovarian cancers.

Successful delivery after transabdominal cerclage of uterine cervix for cervical incompetence after radical trachelectomy.

Pregnancy after radical trachelectomy (RT) has a high risk of prematurity and complications such as preterm premature rupture of the membrane and chorioamnionitis. Placing a cervical cerclage at the time of RT plays an important role in preventing such obstetrical complications. In patients who have trouble with the cervical cerclage, miscarriage during the second trimester seems to be inevitable. We have therefore started preconception transabdominal cerclage (TAC) for these patients. A 36-year-old Japanese woman who had a history of miscarriage due to trouble with the nylon thread used for cerclage, successfully delivered after TAC. TAC is a useful treatment modality to prevent miscarriage for patients who have trouble with cerclage after RT.

BAG3 increases the invasiveness of uterine corpus carcinoma cells by suppressing miR-29b and enhancing MMP2 expression.

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.

BAG3 upregulates Mcl-1 through downregulation of miR-29b to induce anticancer drug resistance in ovarian cancer.

OBJECTIVE: Ovarian cancer is the leading cause of death from gynecologic cancer, reflecting its often late diagnosis and its chemoresistance. We identified a set of microRNAs whose expression is altered upon BAG3 knockdown. Our primary objective was to examine the relationships between BAG3, miR-29b and Mcl-1, an antiapoptotic Bcl-2 family protein, in ovarian cancer cells. METHODS: Ovarian cancer cells were cultured and their responsiveness to paclitaxel was tested. Microarray analysis was performed to identify microRNAs differentially expressed in ES2 BAG3 knockdown ovarian cancer cells and their control cells. Primary ovarian cancer tissues were obtained from 56 patients operated on for ovarian cancer. The patients' clinical and pathological data were obtained from their medical records. RESULTS: BAG3 knockdown increased the chemosensitivity to paclitaxel of ES2 ovarian clear cell carcinoma cells to a greater degree than AMOC2 serous adenocarcinoma cells. qRT-PCR analysis showed that miR-29b expression was significantly upregulated in primary cancer tissue expressing low levels of BAG3, as compared to tissue expressing high levels. Moreover, levels of miR-29b correlated significantly with progression-free survival. Upregulation of miR-29b also reduced levels of Mcl-1 and sensitized ES2 cells to low-dose paclitaxel. CONCLUSIONS: BAG3 knockdown appears to downregulate expression of Mcl-1 through upregulation of miR-29b, thereby increasing the chemosensitivity of ovarian clear cell carcinoma cells. This suggests that BAG3 is a key determinant of the responsiveness of ovarian cancer cells, especially clear cell carcinoma, to paclitaxel and that BAG3 may be a useful therapeutic target for the treatment of ovarian cancer.

First case of vaginal radical trachelectomy in a pregnant Japanese woman.

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.

BAG3 (BCL2-associated athanogene 3) interacts with MMP-2 to positively regulate invasion by ovarian carcinoma cells.

BAG3 (BCL2-associated athanogene 3) is a member of the BAG family proteins, which interact with and regulate Hsp70. Our aim in the present study was to correlate BAG3 expression in ovarian cancer with invasion and progression-free survival. We found that BAG3 interacts with MMP2 in cultured ovarian cancer cells, and that knockdown of BAG3 expression downregulated MMP2 expression and diminished cell motility and invasiveness. The incidence of BAG3 positivity was significantly higher at advanced clinical stages of ovarian cancer than at early stages. We suggest that BAG3 binds to MMP2 to positively regulate the process of cell invasion.