Mohammad Waseem

Mitochondrial dysfunction mediated cisplatin induced toxicity: Modulatory role of curcumin

Anticancer agents help to suppress cellular damage but subsequently can lead to side effects and toxic manifestations. Toxicity of anticancer drug cisplatin (CP) is attributed to its interference of biological enzymes in metabolic pathways. Mitochondria have been recognized as targets in various kinds of toxicity including neurotoxicity and hepatotoxicity that can lead to neoplastic disease. Curcumin (CMN) is a known cytoprotectant with comprehensive anti-inflammatory and anti-cancerous properties. The aim of the present study was to evaluate the damage caused by CP and its abrogation by using antioxidant potential of CMN. CP caused a significant enhancement in the mitochondrial lipid peroxidation (LPO) levels and protein carbonyl (PC) content. Pre-treatment of rat with CMN significantly restored the mitochondrial LPO levels and PC content. It also replenished the CP induced modulatory effects on altered enzymatic and non-enzymatic antioxidants in both brain and liver mitochondria. It is suggested that CMN, by attenuating mitochondrial oxidative stress, holds promise that can decline CP induced adverse effects in brain and liver. CMN should be investigated as a potential safe and remarkable approach in attenuating the adverse effects induced by CP-related toxicants.

Cadmium‐induced hepatotoxicity and its abrogation by thymoquinone

Cadmium (Cd2+) causes alteration of the cellular homeostasis and oxidative damage. The aim of the present study was to investigate the possible protective role of thymoquinone (TQ), a predominant bioactive component present in black seed oil (Nigella sativa) on the hepatotoxicity of Cd2+ with special reference to its protection against perturbation of nonenzymatic and enzymatic antioxidants. The effect of TQ pretreatment was examined in postnuclear supernatant prepared from liver of Swiss albino mice under in vitro conditions. CdCl2 treatment (5 mM) resulted in a significant increase in antioxidant enzymatic activities. It also caused a significant (p < 0.001) increase in protein carbonyl and reduced glutathione content. Pretreatment with TQ (10 μM) showed a significant protection as manifested by noticed attenuation of protein oxidation and rejuvenation of the depleted antioxidants of cellular fraction. These results strengthen the hypothesis that TQ exerts modulatory influence on the antioxidant defense system on being subjected to toxic insult.

Neuroprotective activities of curcumin and quercetin with potential relevance to mitochondrial dysfunction induced by oxaliplatin

Peripheral neurotoxicity is one of the serious dose-limiting side effects of oxaliplatin (Oxa) when used in the treatment of malignant conditions. It is documented that it elicits major side effects specifically neurotoxicity due to oxidative stress forcing the patients to limit its clinical use in long-term treatment. Oxidative stress has been proven to be involved in Oxa-induced toxicity including neurotoxicity. The mitochondria have recently emerged as targets for anticancer drugs in various kinds of toxicity including neurotoxicity that can lead to neoplastic disease. However, there is paucity of literature involving the role of the mitochondria in mediating Oxa-induced neurotoxicity and its underlying mechanism is still debatable. The purpose of this study was to investigate the dose-dependent damage caused by Oxa on isolated brain mitochondria under in vitro conditions. The study was also designed to investigate the neuroprotective effects of nutraceuticals, curcumin (CMN), and quercetin (QR) on Oxa-induced mitochondrial oxidative stress and respiratory chain complexes in the brain of rats. Oxidative stress biomarkers, levels of nonenzymatic antioxidants, activities of enzymatic antioxidants, and mitochondrial complexes were evaluated against the neurotoxicity induced by Oxa. Pretreatment with CMN and QR significantly replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. CMN and QR ameliorated altered nonenzymatic and enzymatic antioxidants and complex enzymes of mitochondria. We conclude that CMN and QR, by attenuating oxidative stress as evident by mitochondrial dysfunction, hold promise as agents that can potentially reduce Oxa-induced adverse effects in the brain.

Postnuclear Supernatant: An In Vitro Model for Assessing Cadmium-Induced Neurotoxicity

Cadmium (Cd) is a toxic heavy metal commonly found in industrial workplaces, a food contaminant and a major constituent of cigarette smoke. Most of the organs are susceptible to Cd-induced toxicity, including brain. Postnuclear supernatant (PNS) has been accepted as an in vitro model for assessing xenobiotic induced toxicity. The goal of the present study was to validate PNS as an in vitro model for investigating the effect of Cd-induced neurotoxicity. Neurotoxic induction by Cd was established in a dose-dependent manner in PNS in vitro. Enzymatic and non-enzymatic antioxidants were used as biomarkers of exposure. Antioxidant enzymatic activity was measured as a significant increase in activities of catalase, superoxide dismutase, and glutathione S-transferase. On exposure to Cd, a significant increase in acetylcholinesterase and decrease in sodium–potassium ATPase activity was also observed. Non-enzymatic effect was also demonstrated as a significant elevation in reduced glutathione and non-protein thiol activity, but there was no significant increase or decrease in the concentrations of protein thiol. In accordance with the toxicity of Cd towards the studied brain structure, Cd-induced oxidative stress has been a focus of toxicological research as a possible mechanism of neurotoxicity. Our results suggest that PNS preparations can be used as a model for future investigation of xenobiotic-induced neurotoxicity under in vitro conditions.

Cisplatin hepatotoxicity mediated by mitochondrial stress

Abstract Context: Chemotherapy has long been the keystone of cancer regimen, and comprehensive research has been done on the development of more potent and less toxic anti-cancer agents. Cisplatin (CP) is a potent and extensively used chemotherapeutic agent. There is paucity of literature involving role of mitochondria in mediating CP-induced hepatic toxicity, and its underlying mechanism remains unclear. Oxidative stress is a well-established biomarker of the mitochondrial toxicity. Objective: This study evaluates the dose-dependent effects of CP-induced mitotoxicity under in vitro conditions, using mitochondria from rat liver. Materials and methods: The aim of our study was to determine the effect of CP with different concentrations in isolated liver mitochondria as an in vitro model. Results: CP exposure showed significantly compromised level of non enzymatic and enzymatic antioxidants with higher extent of lipid and protein oxidation. CP also caused significant alterations in the activity of respiratory chain enzymes (complex I–III and V) in liver mitochondria. Discussion and conclusion: It is suggested that mitochondria can be employed as a model for future investigations of anticancer drug-induced hepatotoxicity under in vitro conditions. Studies with selected pharmaceuticals and nutraceuticals might certainly play a definite role in deciphering cellular and molecular mechanisms of CP-induced hepatotoxicity and its amelioration.

Mitochondria-mediated mitigatory role of curcumin in cisplatin-induced nephrotoxicity

Cisplatin (CP) is one of the most potent chemotherapeutic anti‐tumour drugs, and it has been implicated in renal toxicity. Oxidative stress has been proven to be involved in CP‐induced toxicity including nephrotoxicity. However, there is paucity of literature involving role of mitochondria in mediating CP‐induced renal toxicity, and its underlying mechanism remains unclear. Therefore, the present study was undertaken to examine the antioxidant potential of curcumin (CMN; a natural polyphenolic compound) against the mitochondrial toxicity of CP in kidneys of male rats. Acute toxicity was induced by a single intra‐peritoneal injection of CP (6 mg kg−1). We studied the ameliorative effect of CMN pre‐treatment (200 mg kg−1) on the toxicity of CP in rat kidney mitochondria. CP caused a significant elevation in the mitochondrial lipid peroxidation (LPO) levels and protein carbonyl (PC) content. Pre‐treatment of rat with CMN significantly replenished the mitochondrial LPO levels and PC content. It also restored the CP‐induced modulatory effects on altered enzymatic and non‐enzymatic antioxidants in kidney mitochondria. We hypothesize that the reno‐protective effects of CMN may be related to its predisposition to scavenge free radicals, and upregulate antioxidant machinery in kidney mitochondria. Copyright

Ameliorative Action of Curcumin in Cisplatin-mediated Hepatotoxicity: An In Vivo Study in Wistar Rats

BACKGROUND AND AIMS Cisplatin (CP) is regarded as a major anticancer drug against a wide spectrum of leukemia and other malignancies. The mode of action of CP on cancer cells is attributed to its property of releasing free radicals which, at the same time, has the potential to damage liver and kidney cells. The tissue-specific toxicity of CP to the kidneys is well documented. However, there is a paucity of literature on systemic toxicity and also the amelioration of such effect. The aim of the present study was to evaluate the damage caused by CP and its modulation by using the antioxidant capacity of curcumin (CMN, a natural polyphenolic compound) in Wistar rats. METHODS We evaluated the ameliorative effect of CMN (200 mg/kg body weight, b.w.) on the toxicity of CP in rat liver. Oxidative stress biomarkers, enzymatic and nonenzymatic antioxidants were evaluated for assessing the mitigatory potential of CMN against CP-induced toxicity. RESULTS A single dose of CP (7 mg/kg b.w.) caused marked hepatic damage. CP caused a significant increase in lipid peroxidation (LPO) level and protein carbonyl (PC) content. Pretreatment of rat with CMN significantly restored the LPO levels and PC content. It also replenished the CP-induced modulatory effects on altered enzymatic and nonenzymatic antioxidants in liver. CONCLUSION Our results clearly demonstrated that the role of oxidative stress is detrimental in systemic toxicity induced by CP and suggest a mitigatory effect of CMN on CP-induced hepatotoxicity in rat.

Neuroprotective effects of melatonin as evidenced by abrogation of oxaliplatin induced behavioral alterations, mitochondrial dysfunction and neurotoxicity in rat brain

Neurotoxicity is a burdensome consequence of platinum-based chemotherapy that neutralizes the administration of effective dosage and often prompts treatment withdrawal. Oxaliplatin (Oxa), a third-era platinum analogue that is active against both early-organize and progressed colorectal growth, produces critical neurotoxicity. It has been reported that the Melatonin (Mel) is a pineal hormone its metabolites display important antioxidant properties in nervous system. There is dearth of literature involving the role of mitochondria and cytosolic compartments mediated Oxa-induced neurotoxicity and its underlying mechanisms are still debatable. Rats were pre-treated with Mel (10mg/kg b.wt., i.p.) and treated with Oxa (4mg/kg b.wt. i.p.) for 5 consecutive days. For neurobehavioral performances, decreased locomotor activity and muscular strength were observed in rats. Treatment with Mel in Oxa treated rats could protect the Oxa induced alterations in motor activity and muscular strength. For painful neuropathy, thermal hyperalgesia/nociceptive tests were evaluated. In addition, pre-treatment of Mel could block or alter the inactivation of Bcl-2, caspase 3 apoptotic protein and alterations Cytochrome c (Cyt c) release in an Oxa rich environment. Pre-treatment of Mel have shown an alteration in hyperalgesia behaviour in Oxa treated rats. Oxidative stress biomarkers, levels of non-enzymatic antioxidants and mitochondrial complexes were evaluated against neurotoxicity induced by Oxa. Mel pre-treatment replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. Mel also modulated altered non-enzymatic, enzymatic antioxidants and complex enzymes of mitochondria. Futures studies are also required to identify other molecular markers involved in neurotoxicity induced by Oxa and possible action of Mel in its modulation.

Melatonin pre-treatment mitigates SHSY-5Y cells against oxaliplatin induced mitochondrial stress and apoptotic cell death

Oxaliplatin (Oxa) treatment to SH-SY5Y human neuroblastoma cells has been shown by previous studies to induce oxidative stress, which in turn modulates intracellular signaling cascades resulting in cell death. While this phenomenon of Oxa-induced neurotoxicity is known, the underlying mechanisms involved in this cell death cascade must be clarified. Moreover, there is still little known regarding the roles of neuronal mitochondria and cytosolic compartments in mediating Oxa-induced neurotoxicity. With a better grasp of the mechanisms driving neurotoxicity in Oxa-treated SH-SY5Y cells, we can then identify certain pathways to target in protecting against neurotoxic cell damage. Therefore, the purpose of this study was to determine whether one such agent, melatonin (Mel), could confer protection against Oxa-induced neurotoxicity in SH-SY5Y cells. Results from the present study found Oxa to significantly reduce SH-SY5Y cell viability in a dose-dependent manner. Alternatively, we found Mel pre-treatment to SH-SY5Y cells to attenuate Oxa-induced toxicity, resulting in a markedly increased cell viability. Mel exerted its protective effects by regulating reactive oxygen species (ROS) production and reducing superoxide radicals inside Oxa-exposed. In addition, we observed pre-treatment with Mel to rescue Oxa-treated cells by protecting mitochondria. As Oxa-treatment alone decreases mitochondrial membrane potential (Δψm), resulting in an altered Bcl-2/Bax ratio and release of sequestered cytochrome c, so Mel was shown to inhibit these pathways. Mel was also found to inhibit proteolytic activation of caspase 3, inactivation of Poly (ADP Ribose) polymerase, and DNA damage, thereby allowing SH-SY5Y cells to resist apoptotic cell death. Collectively, our results suggest a role for melatonin in reducing Oxa induced neurotoxicity. Further studies exploring melatonin’s protective effects may prove successful in eliciting pathways to further alter the neurotoxic pathways of platinum compounds in cancer treatment.

Role of Mitochondrial Mechanism in Chemotherapy-Induced Peripheral Neuropathy

BACKGROUND Even though chemotherapeutic regimens show considerable importance, it may cause progressive, continuing and sometimes irreversible peripheral neuropathy. Chemotherapy induced peripheral neuropathy (CIPN) is comprised of sensory abnormalities that are most distressing issues. The mechanism associated with CIPN pathogenesis is not completely revealed and its treatment is still questionable. The purpose of this review was to investigate the role of mitochondria in CIPN. METHODS This review is literature based that describes the mitochondrial mechanism underlying CIPN and the neuropathic complications associated with different antineoplastic agents. RESULTS For severe pain, a modification towards less efficient chemotherapeutic drugs could possibly be needed and/or patients perhaps prefer to withdrawal therapeutic regimen. The epidemiology of CIPN is still debatable. The major recurrent molecules causing CIPN are platinum based drugs including cisplatin and oxaliplatin, thalidomide, bortezomib, vinka alkaloids and taxanes. Neuropathic pain is one of the symptoms of CIPN. Various neuropathic disorders as well as CIPN are due to mitochondrial impairment, relevant impairment of Ca2+ signalling pathways and reactive oxygen species (ROS) that ultimately leads to apoptosis. CONCLUSION The pathophysiology of CIPN is complicated as chemotherapeutic medications often involve combination of drugs. With these combinatorial therapies cancer survivors develop continuing effects of CIPN which require rehabilitation strategies for the recovery of patients condition and quality of life.