Role of the Mitochondria in Immune-Mediated Apoptotic Death of the Human Pancreatic β Cell Line βLox5

Mitochondria are indispensable in the life and death of many types of eukaryotic cells. In pancreatic beta cells, mitochondria play an essential role in the secretion of insulin, a hormone that regulates blood glucose levels. Unregulated blood glucose is a hallmark symptom of diabetes. The onset of Type 1 diabetes is preceded by autoimmune-mediated destruction of beta cells. However, the exact role of mitochondria has not been assessed in beta cell death. In this study, we examine the role of mitochondria in both Fas- and proinflammatory cytokine-mediated destruction of the human beta cell line, βLox5. IFNγ primed βLox5 cells for apoptosis by elevating cell surface Fas. Consequently, βLox5 cells were killed by caspase-dependent apoptosis by agonistic activation of Fas, but only after priming with IFNγ. This beta cell line undergoes both apoptotic and necrotic cell death after incubation with the combination of the proinflammatory cytokines IFNγ and TNFα. Additionally, both caspase-dependent and -independent mechanisms that require proper mitochondrial function are involved. Mitochondrial contributions to βLox5 cell death were analyzed using mitochondrial DNA (mtDNA) depleted βLox5 cells, or βLox5 ρ0 cells. βLox5 ρ0 cells are not sensitive to IFNγ and TNFα killing, indicating a direct role for the mitochondria in cytokine-induced cell death of the parental cell line. However, βLox5 ρ0 cells are susceptible to Fas killing, implicating caspase-dependent extrinsic apoptotic death is the mechanism by which these human beta cells die after Fas ligation. These data support the hypothesis that immune mediators kill βLox5 cells by both mitochondrial-dependent intrinsic and caspase-dependent extrinsic pathways

Contemporary update on neoadjuvant therapy for bladder cancer.

Administration of neoadjuvant chemotherapy preceding radical cystectomy in patients with bladder cancer remains a matter of debate. Results of prospective, randomized studies have demonstrated an overall absolute survival benefit of 5% at 5 years, provided cisplatin-based combination regimens are used. Owing to the perception of a modest survival benefit, the medical community has been slow to adopt the use of neoadjuvant chemotherapy. Other reasons for the underuse of neoadjuvant chemotherapy range from patient ineligibility to fear of delaying potentially curative surgery in nonresponders. Instead, several institutions have adopted an individualized, risk-adapted approach, in which the decision to administer chemotherapy is based on clinical stage and patient comorbidity profile. The development of new cytotoxic and targeted therapies, in particular immune checkpoint inhibitors, warrants well-designed prospective studies to test their efficacy alone or in combination in the neoadjuvant setting. Moving forward, genomic characterization of muscle-invasive bladder cancer could offer information that aids clinicians in selecting the appropriate chemotherapy regimen. Following neoadjuvant therapy, every effort should be made to ensure optimal surgery, as surgical margins and the number of removed lymph nodes are prognostic factors; thus, radical cystectomy and a meticulous extended pelvic lymph node dissection should be performed by expert surgeons