Introduction. Cisplatin, a platinum‐based antineoplastic agent, is the cornerstone for the treatment of many malignancies. Nephrotoxicity is the primary dose‐limiting toxicity, and various hydration regimens and supplementation strategies are used to prevent cisplatin‐induced kidney injury. However, evidence‐based recommendations on specific hydration regimens are limited. A systematic review was performed to evaluate clinical studies that have examined hydration and supplementation strategies to prevent cisplatin‐induced nephrotoxicity. Materials and Methods. PubMed and Excerpta Medica databases were searched from 1966 through October 2015 for clinical trials and other studies focused on hydration regimens to prevent nephrotoxicity in cancer patients treated with cisplatin. The University of Oxford Centre for Evidence‐Based Medicine criteria were used to grade level of evidence. Results. Among the 1,407 identified studies, 24 were included in this systematic review. All studies differed on type, volume, and duration of hydration. Among the 24 studies, 5 evaluated short‐duration hydration, 4 evaluated low‐volume hydration, 4 investigated magnesium supplementation, and 7 reviewed forced diuresis with hydration. Short‐duration and lower‐volume hydration regimens are effective in preventing cisplatin‐induced nephrotoxicity. Magnesium supplementation may have a role as a nephroprotectant, and forced diuresis may be appropriate in some patients receiving cisplatin. Conclusion. Hydration is essential for all patients to prevent cisplatin‐induced nephrotoxicity. Specifically, short‐duration, low‐volume, outpatient hydration with magnesium supplementation and mannitol forced diuresis (in select patients) represent best practice principles for the safe use of cisplatin. The Oncologist 2017;22:609–619 Implications for Practice. The findings contained within this systematic review show that (a) hydration is essential for all patients to prevent cisplatin‐induced nephrotoxicity, (b) short‐duration, low‐volume, outpatient hydration regimens appear to be safe and feasible, even in patients receiving intermediate‐ to high‐dose cisplatin, (c) magnesium supplementation (8–16 milliequivalents) may limit cisplatin‐induced nephrotoxicity, and (d) mannitol may be considered for high‐dose cisplatin and/or patients with preexisting hypertension. These findings have broad implications for clinical practice and represent best practice principles for the prevention of cisplatin‐induced nephrotoxicity.

William Evans and colleagues find that the proinflammatory genes CASP1 and NLRP3 are expressed at higher levels in primary acute lymphoblastic leukemia cells that are resistant than in those that are sensitive to glucocorticoid treatment. They find that CASP1 mediates glucocorticoid resistance through cleavage of the glucocorticoid receptor. Glucocorticoids are universally used in the treatment of acute lymphoblastic leukemia (ALL), and resistance to glucocorticoids in leukemia cells confers poor prognosis. To elucidate mechanisms of glucocorticoid resistance, we determined the prednisolone sensitivity of primary leukemia cells from 444 patients newly diagnosed with ALL and found significantly higher expression of CASP1 (encoding caspase 1) and its activator NLRP3 in glucocorticoid-resistant leukemia cells, resulting from significantly lower somatic methylation of the CASP1 and NLRP3 promoters. Overexpression of CASP1 resulted in cleavage of the glucocorticoid receptor, diminished the glucocorticoid-induced transcriptional response and increased glucocorticoid resistance. Knockdown or inhibition of CASP1 significantly increased glucocorticoid receptor levels and mitigated glucocorticoid resistance in CASP1-overexpressing ALL. Our findings establish a new mechanism by which the NLRP3-CASP1 inflammasome modulates cellular levels of the glucocorticoid receptor and diminishes cell sensitivity to glucocorticoids. The broad impact on the glucocorticoid transcriptional response suggests that this mechanism could also modify glucocorticoid effects in other diseases.

Familial pulmonary arterial hypertension (PAH) is associated with mutations in bone morphogenetic protein type II receptor (BMPR2). Many of these mutations occur in the BMPR2 tail domain, leaving the SMAD functions intact. To determine the in vivo consequences of BMPR2 tail domain mutation, we created a smooth muscle-specific doxycycline-inducible BMPR2 mutation with an arginine to termination mutation at amino acid 899. When these SM22-rtTA x TetO₇-BMPR2^R899X mice had transgene induced for 9 wk, starting at 4 wk of age, they universally developed pulmonary vascular pruning as assessed by fluorescent microangiography. Approximately one-third of the time, the induced animals developed elevated right ventricular systolic pressures (RVSP), associated with extensive pruning, muscularization of small pulmonary vessels, and development of large structural pulmonary vascular changes. These lesions included large numbers of macrophages and T cells in their adventitial compartment as well as CD133-positive cells in the lumen. Small vessels filled with CD45-positive and sometimes CD3-positive cells were a common feature in all SM22-rtTA x TetO₇-BMPR2^R899X mice. Gene array experiments show changes in stress response, muscle organization and function, proliferation, and apoptosis and developmental pathways before RVSP increases. Our results show that the primary phenotypic result of BMPR2 tail domain mutation in smooth muscle is pulmonary vascular pruning leading to elevated RVSP, associated with early dysregulation in multiple pathways with clear relevance to PAH. This model should be useful to the research community in examining early molecular and physical events in the development of PAH and as a platform to validate potential treatments.

Despite the initial efficacy of androgen deprivation in prostate cancer, virtually all patients progress to castration-resistant prostate cancer (CRPC). Androgen receptor (AR) signaling is critically required for CRPC. A new generation of medications targeting AR, such as abiraterone and enzalutamide, has improved survival of metastatic CRPC (mCRPC) patients. However, a significant proportion of patients presents with primary resistance to these agents, and in the remainder, secondary resistance will invariably develop, which makes mCRPC the lethal form of the disease. Mechanisms underlying progression to mCRPC and treatment resistance are extremely complex. AR-dependent resistance mechanisms include AR amplification, AR point mutations, expression of constitutively active AR splice variants, and altered intratumoral androgen biosynthesis. AR-independent resistance mechanisms include glucocorticoid receptor activation, immune-mediated resistance, and neuroendocrine differentiation. The development of novel agents, such as seviteronel, apalutamide, and EPI-001/EPI-506, as well as the identification and validation of novel predictive biomarkers of resistance, may lead to improved therapeutics for mCRPC patients.

Idiopathic pulmonary arterial hypertension (IPAH) in human patients is associated with mutations in type 2 receptor for the bone morphogenic protein pathway (BMPR2). Mice expressing an inducible dominant negative form of BMPR2 in smooth muscle develop elevated right ventricular pressures when the transgene is activated. We hypothesized that transcriptional changes in these mice may allow insight into the early molecular events leading to IPAH. Microarray analysis was used to examine the transcriptional changes induced in whole lung by loss of normal smooth muscle cell (SMC) BMPR2 signaling in adult male or female mice (12 wk at time of death) expressing the transgene for either 1 or 8 wk. Our key results include a decrease in markers of smooth muscle differentiation, an increase in cytokines and markers of immune response, particularly in female mice, and a decrease in angiogenesis-related genes. These broad patterns of gene expression appear as early as 1 wk and are well established by 8 wk. Results were confirmed by quantitative RT-PCR to RNA from individual mice. Primary pulmonary artery SMC cultures transfected with small interfering RNA to BMPR2 also show loss of SMC markers myosin heavy chain 11 and calponin by quantitative RT-PCR and Western blot. These studies show classes of genes differentially regulated in response to loss of BMPR2 in SMC in vivo with clear relevance to the IPAH disease process, suggesting that the relevance of BMPR2 dysregulation may extend beyond proliferation.