Repurposing AZD5438 and Dabrafenib for Cisplatin-Induced AKI.

SIGNIFICANCE STATEMENT: To combat both untoward effects of nephrotoxicity and ototoxicity in cisplatin-treated patients, two potential therapeutic oral anticancer drugs AZD5438 and dabrafenib, a phase-2 clinical trial protein kinase CDK2 inhibitor and an US Food and Drug Administration-approved drug BRAF inhibitor, respectively, were tested in an established mouse AKI model. Both drugs have previously been shown to protect significantly against cisplatin-induced hearing loss in mice. Each drug ameliorated cisplatin-induced increases in the serum biomarkers BUN, creatinine, and neutrophil gelatinase-associated lipocalin. Drugs also improved renal histopathology and inflammation, mitigated cell death by pyroptosis and necroptosis, and significantly enhanced overall survival of cisplatin-treated mice. BACKGROUND: Cisplatin is an effective chemotherapy agent for a wide variety of solid tumors, but its use is dose-limited by serious side effects, including AKI and hearing loss. There are no US Food and Drug Administration-approved drugs to treat both side effects. Recently, two anticancer oral drugs, AZD5438 and dabrafenib, were identified as protective against cisplatin-induced hearing loss in mice. We hypothesize that similar cell stress and death pathways are activated in kidney and inner ear cells when exposed to cisplatin and tested whether these drugs alleviate cisplatin-induced AKI. METHODS: The HK-2 cell line and adult FVB mice were used to measure the protection from cisplatin-induced cell death and AKI by these drugs. Serum markers of kidney injury, BUN, creatinine, and neutrophil gelatinase-associated lipocalin as well as histology of kidneys were analyzed. The levels of markers of kidney cell death, including necroptosis and pyroptosis, pERK, and proliferating cell nuclear antigen, were also examined by Western blotting and immunofluorescence. In addition, CDK2 knockout (KO) mice were used to confirm AZD5438 protective effect is through CDK2 inhibition. RESULTS: The drugs reduced cisplatin-induced cell death in the HK-2 cell line and attenuated cisplatin-induced AKI in mice. The drugs reduced serum kidney injury markers, inhibited cell death, and reduced the levels of pERK and proliferating cell nuclear antigen, all of which correlated with prolonged animal survival. CDK2 KO mice were resistant to cisplatin-induced AKI, and AZD5438 conferred no additional protection in the KO mice. CONCLUSIONS: Cisplatin-induced damage to the inner ear and kidneys shares similar cellular beneficial responses to AZD5438 and dabrafenib, highlighting the potential therapeutic use of these agents to treat both cisplatin-mediated kidney damage and hearing loss.

Dabrafenib protects from cisplatin-induced hearing loss in a clinically relevant mouse model.

The widely used chemotherapy cisplatin causes permanent hearing loss in 40%-60% of patients with cancer. One drug, sodium thiosulfate, is approved by the FDA for use in pediatric patients with localized solid tumors for preventing cisplatin-induced hearing loss, but more drugs are desperately needed. Here, we tested dabrafenib, an FDA-approved BRAF kinase inhibitor and anticancer drug, in a clinically relevant multidose cisplatin mouse model. The protective effects of dabrafenib, given orally twice daily with cisplatin, were determined by functional hearing tests and cochlear outer hair cell counts. Toxicity of the drug cotreatment was evaluated, and levels of phosphorylated ERK were measured. A dabrafenib dose of 3 mg/kg BW, twice daily, in mice, was determined to be the minimum effective dose, and it is equivalent to one-tenth of the daily FDA-approved dose for human cancer treatment. The levels of hearing protection acquired, 20-25 dB at the 3 frequencies tested, in both female and male mice, persisted for 4 months after completion of treatments. Moreover, dabrafenib exhibited a good in vivo therapeutic index (> 25), protected hearing in 2 mouse strains, and diminished cisplatin-induced weight loss. This study demonstrates that dabrafenib is a promising candidate drug for protection from cisplatin-induced hearing loss.

Evaluation of anti-arthritic potential of Trigonella foenum graecum L. (Fenugreek) mucilage against rheumatoid arthritis.

Rheumatoid arthritis is a chronic inflammatory joint disease characterized by synovial proliferation and tissue destruction. Pro-inflammatory cytokines like interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) play a key role in the disease process and elevate energy expenditure, which further increases the joint pain and stiffness. The present study was undertaken to explore the anti-arthritic potential of fenugreek mucilage in adjuvant induced arthritic rats. In the present study, paw volume was measured on the 7th, 14th and 21st day. Finally, animals were anaesthetized; blood samples and tissues were collected for the assay of inflammatory enzymes like cyclooxygenase, lipoxygenase; evaluated the level of cytokines like IL-6, TNF-α, arthritic index and rheumatoid factor. Fenugreek mucilage exhibited maximum percentage of edema inhibition at a dose of 75 mg/kg on 21st day of adjuvant arthritis. The effect was higher than that of standard drug, indomethacin. The activities of inflammatory enzymes and concentration of mediators were decreased on treatment with fenugreek mucilage. Cytology of synovial fluid showed mild inflammation with normal synoviocytes (mesothelial cells) tried to bring back to normal characteristics on supplementation with fenugreek mucilage. Based on the observations, it can be suggested that fenugreek mucilage possesses promising anti-arthritic property and it can be used as a therapeutic agent for arthritis.

Comparative effect of horse gram and black gram on inflammatory mediators and antioxidant status.

A balanced diet is important for the overall wellbeing of an individual. Pulses are an important part of a nutritive diet. Pulses have been consumed for at least 10,000 years and are among the most extensively used foods in the world. They are a rich source of protein and fiber, as well as a significant source of vitamins and minerals, such as iron, zinc, and magnesium. The purpose of this study was to compare the effect of two pulses, horse gram and black gram, on inflammatory mediators and the antioxidant enzymes. Two sets of experiments were conducted in rats which were fed with boiled and unboiled horse gram and black gram, at a dose of 100 mg/100 g body weight, for 21 days and 60 days. The results showed that horse gram supplementation for 21 days and 60 days significantly increased the activities of antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase and showed no significant changes in the activities of the inflammatory mediators such as cyclooxygenase, lipoxygenase, myeloperoxidase, nitric oxide synthase, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1ß), etc. However, the black gram (with skin and without skin) supplementation significantly increased activities of the inflammatory mediators and showed a significant decrease in the antioxidant enzymes in both the 21-day and 60-day experiments. Thus, these preliminary results demonstrate the anti-inflammatory and antioxidant potential of horse gram and the proinflammatory effects of black gram in rats. This is in accordance with the dietary regime advised by Ayurveda practitioners, where horse gram is to be included and black gram is to be excluded from the diet for conditions such as rheumatoid arthritis. Further studies are to be conducted to validate the same.

Attenuation of atherosclerotic complications by modulating inflammatory responses in hypercholesterolemic rats with dietary Njavara rice bran oil.

Atherosclerosis is a chronic inflammatory disease. The role of inflammation in atherosclerosis is well established, with all stages of disease progression being assessed as inflammatory response to injury. Preventive treatments and drugs identified so far are based on lipid lowering strategies which also involves functional foods and dietary supplementation. The present study investigated the effect of supplementation of Njavara rice bran oil (NjRBO), extracted from a medicinal rice variety, to high cholesterol diet (HCD) fed rats on atherosclerosis by attenuating the inflammatory responses in PBMCs, aortic endothelial cells and macrophages. Adult male rats (Sprague-Dawley strain, weighing 100-120g) were grouped into 3 of six rats each. Group I served as control, Group II were fed high cholesterol diet (HCD) and Group III were fed a HCD and NjRBO (100mg/kg body weight). The experimental duration was 60days. Activities of cyclooxygenase, lipoxygenase, nitric oxide synthase, and myeloperoxidase, expression of Tumor necrosis factor-α, Interleukin-6, Interferon γ, monocyte chemoattractant protein-1, and cytosolic phospholipase A2 were found to be decreased on NjRBO supplementation which were increased in HCD fed rats. Expression of ICAM-1 and VCAM-1 in aortic endothelial cells was decreased significantly in NjRBO treatment than HCD fed rats. This attenuations were mainly due to inhibition in translocation of NF-κB into nucleus in aortic endothelial cells. Also, NjRBO treatment significantly decreased the gene expressions of TLR-2, TLR-4, and CD36 in both macrophages and endothelial cells than HCD fed rats indicates its anti-inflammatory effect via TLR - NF-κB signaling pathway. NjRBO has thereby shown to possess anti-atherogenic property by effectively modulating inflammatory mechanisms.

Tricin, flavonoid from Njavara reduces inflammatory responses in hPBMCs by modulating the p38MAPK and PI3K/Akt pathways and prevents inflammation associated endothelial dysfunction in HUVECs.

Previous studies revealed the potent anti-inflammatory activity of tricin, the active component of Njavara rice bran. Here, we report the involvement of specific signaling pathways in the protective effect of tricin against LPS induced inflammation in hPBMCs and the role of tricin in modulating endothelial dysfunction in LPS induced HUVECs. Pretreatment with tricin (15µM) significantly inhibited the release of TNF-α and was comparable to the specific pathway blockers like ERK inhibitor (PD98059), JNK inhibitor (SP600125) and p38 inhibitor (SB203580), whereas an increased release of TNF-α was observed in PI3K/Akt inhibitor (LY294002) treated cells. Tricin alone and combination treatment of tricin and SB203580 showed more significant inhibition of activation of COX-2 and TNF-α than that of SB203580 alone treated group. Combination treatment of tricin and LY294002 showed increased activation of COX-2 and TNF-α, proved that PI3K activation is essential for the anti-inflammatory effect of tricin. Studies conducted on HUVECs revealed the protective effect of tricin against endothelial dysfunction associated with LPS induced inflammation by inhibiting the activation of proinflammatory mediators like TNF-α, IFN-γ, MCP 1 by modulating NF-κB and MAPK signaling pathways. ELISA and flow cytometric analysis again confirmed the protection of tricin against endothelial damage, especially from the decreased activation of cell adhesion molecules like ICAM-1, VCAM-1 and E-Selectin upon tricin treatment. This work establishes the mechanism behind the potent anti-inflammatory activity of the flavonoid tricin.