Cabozantinib Unlocks Efficient In Vivo Targeted Delivery of Neutrophil-Loaded Nanoparticles into Murine Prostate Tumors.

A major barrier to the successful application of nanotechnology for cancer treatment is the suboptimal delivery of therapeutic payloads to metastatic tumor deposits. We previously discovered that cabozantinib, a tyrosine kinase inhibitor, triggers neutrophil-mediated anticancer innate immunity, resulting in tumor regression in an aggressive PTEN/p53-deficient genetically engineered murine model of advanced prostate cancer. Here, we specifically investigated the potential of cabozantinib-induced neutrophil activation and recruitment to enhance delivery of BSA-coated polymeric nanoparticles (BSA-NPs) into murine PTEN/p53-deficient prostate tumors. On the basis of the observation that BSA coating of NPs enhanced association and internalization by activated neutrophils by approximately 6-fold in vitro, relative to uncoated NPs, we systemically injected BSA-coated, dye-loaded NPs into prostate-specific PTEN/p53-deficient mice that were pretreated with cabozantinib. Flow cytometric analysis revealed an approximately 4-fold increase of neutrophil-associated BSA-NPs and an approximately 32-fold increase in mean fluorescent dye uptake following 3 days of cabozantinib/BSA-NP administration, relative to BSA-NP alone. Strikingly, neutrophil depletion with Ly6G antibody abolished dye-loaded BSA-NP accumulation within tumors to baseline levels, demonstrating targeted neutrophil-mediated intratumoral NP delivery. Furthermore, we observed an approximately 13-fold decrease in accumulation of BSA-NPs in the liver, relative to uncoated NPs, post-cabozantinib treatment, suggesting that BSA coating of NPs can significantly enhance cabozantinib-induced, neutrophil-mediated targeted intratumoral drug delivery, while mitigating off-target toxicity. Collectively, we demonstrate a novel targeted nano-immunotherapeutic strategy for enhanced intratumoral delivery of BSA-NPs, with translational potential to significantly augment therapeutic indices of cancer medicines, thereby overcoming current pharmacologic barriers commonly encountered in preclinical/early-phase drug development.

A protective role of Gαq-RGS2 loop activator on streptozotocin induced diabetic complications in rats: An independent on elevated serum glucose level modulation.

An overactivation of Gαq dependent signaling pathway is crucial for development of metabolic and vascular abnormalities in diabetes. Therefore, our objective was to study effects of Gαq-RGS2 loop activator (1-(5-chloro-2-hydroxyphenyl)-3-(4-(trifluoromethyl)phenyl)-1H-1,2,4-triazol-5(4H)-one) on STZ induced diabetic complications in rats. Animals were divided into four groups; normal rats, diabetic rats (Streptozotocin, STZ, 60mg/kg, i.p.), Gαq-RGS2 loop activator (1mg/kg/d, i.p., 15 d, at 6 wk after citrate buffer or STZ administration, respectively) treated normal rats and diabetic rats. At the end of 8 wk, the metabolic parameters, hemodynamic parameters, in-vivo vascular reactivity and aortic anti-oxidant status were evaluated. A treatment of Gαq-RGS2 loop activator significantly decreased serum cholesterol (P < 0.001), triglyceride (P < 0.01), systolic/diastolic/mean arterial blood pressure (P < 0.001), lactate dehydrogenase (P < 0.001), cardiac selective creatinine kinase (P < 0.001), urea (P < 0.05), creatinine (P < 0.001), aortic superoxide dismutase (P < 0.05) and catalase(P < 0.05) in diabetic rats whereas increased basal (P < 0.05) and stimulated (acetylcholine (P < 0.01) and nitroglycerine (P < 0.05)) serum nitric oxide level without affecting elevated serum glucose level. The nitroglycerin stimulated NO production was significantly (P < 0.01) increased by Gαq-RGS2 loop activator administration in normal rats, too. Collectively, Gαq-RGS2 loop activator protects rats against streptozotocin induce hemodynamic and metabolic modulation without affecting elevated serum glucose level.