Hesperidin activates Nrf2 to protect cochlear hair cells from cisplatin-induced damage.

Cisplatin is widely employed in clinical oncology as an anticancer chemotherapy drug in clinical practice and is known for its severe ototoxic side effects. Prior research indicates that the accumulation of reactive oxygen species (ROS) plays a pivotal role in cisplatin's inner ear toxicity. Hesperidin is a flavanone glycoside extracted from citrus fruits that has anti-inflammatory and antioxidant effects. Nonetheless, the specific pharmacological actions of hesperidin in alleviating cisplatin-induced ototoxicity remain elusive. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical mediator of the cellular oxidative stress response, is influenced by hesperidin. Activation of Nrf2 was shown to have a protective effect against cisplatin-induced ototoxicity. The potential of hesperidin to stimulate Nrf2 in attenuating cisplatin's adverse effects on the inner ear warrants further investigation. This study employs both in vivo and in vitro models of cisplatin ototoxicity to explore this possibility. Our results reveal that hesperidin mitigates cisplatin-induced ototoxicity by activating the Nrf2/NQO1 pathway in sensory hair cells, thereby reducing ROS accumulation, preventing hair cell apoptosis, and alleviating hearing loss.

Reversible and monitorable nephrotoxicity in rats by the novel potent transcriptional enhanced associate domain (TEAD) inhibitor, K-975.

The Hippo pathway plays an important role in the growth, development, and regeneration of cells and organs. Transcriptional enhanced associate domain (TEAD), a transcription activator of the Hippo pathway, forms the complex with a transcriptional coactivator yes-associated protein (YAP) or a transcriptional coactivator PDZ-binding motif (TAZ). Their excessive activations are involved in carcinogenesis such as malignant pleural mesothelioma (MPM), and thus inhibition of the TEAD complex is expected to have potent anticancer activity against MPM. On the other hand, YAP or TAZ conditional knockout mice have been reported to show abnormal findings in various tissues, including the kidney, liver, and lung. In the present study, we evaluated the systemic toxicity of K-975, a novel TEAD inhibitor, in rats. When K-975 was administered orally to rats for 1 week, proteinuria suggestive of nephrotoxicity was observed. Electron microscopy revealed that K-975 at 300 mg/kg induced glomerular podocyte foot process effacement. After a 2-week recovery period, proteinuria with foot process effacement was recovered completely. Urinalysis and urinary biomarker evaluation suggested that the urinary albumin index (urinary albumin/urinary creatinine) was the most sensitive marker for detecting K-975-induced nephrotoxicity. After 3 cycles of 1-week administration followed by 2-week recovery periods, nephrotoxicity was reversible; however, incomplete reversibility was observed in rats with severe proteinuria. In conclusion, this study revealed that in rats, oral K-975 treatment induced severe proteinuria by podocyte foot process effacement, which was reversible and monitorable by the urinary albumin index, suggesting important information for developing K-975 as an anticancer drug.

Phytic Acid Maintains Peripheral Neuron Integrity and Enhances Survivability against Platinum-Induced Degeneration via Reducing Reactive Oxygen Species and Enhancing Mitochondrial Membrane Potential.

Phytic acid (PA) has been reported to possess anti-inflammatory and antioxidant properties that are critical for neuroprotection in neuronal disorders. This raises the question of whether PA can effectively protect sensory neurons against chemotherapy-induced peripheral neuropathy (CIPN). Peripheral neuropathy is a dose-limiting side effect of chemotherapy treatment often characterized by severe and abnormal pain in hands and feet resulting from peripheral nerve degeneration. Currently, there are no effective treatments available that can prevent or cure peripheral neuropathies other than symptomatic management. Herein, we aim to demonstrate the neuroprotective effects of PA against the neurodegeneration induced by the chemotherapeutics cisplatin (CDDP) and oxaliplatin. Further aims of this study are to provide the proposed mechanism of PA-mediated neuroprotection. The neuronal protection and survivability against CDDP were characterized by axon length measurements and cell body counting of the dorsal root ganglia (DRG) neurons. A cellular phenotype study was conducted microscopically. Intracellular reactive oxygen species (ROS) was estimated by fluorogenic probe dichlorofluorescein. Likewise, mitochondrial membrane potential (MMP) was assessed by fluorescent MitoTracker Orange CMTMRos. Similarly, the mitochondria-localized superoxide anion radical in response to CDDP with and without PA was evaluated. The culture of primary DRG neurons with CDDP reduced axon length and overall neuronal survival. However, cotreatment with PA demonstrated that axons were completely protected and showed increased stability up to the 45-day test duration, which is comparable to samples treated with PA alone and control. Notably, PA treatment scavenged the mitochondria-specific superoxide radicals and overall intracellular ROS that were largely induced by CDDP and simultaneously restored MMP. These results are credited to the underlying neuroprotection of PA in a platinum-treated condition. The results also exhibited that PA had a synergistic anticancer effect with CDDP in ovarian cancer in vitro models. For the first time, PA's potency against CDDP-induced PN is demonstrated systematically. The overall findings of this study suggest the application of PA in CIPN prevention and therapeutic purposes.

Combined genetic polymorphisms of the GSTT1 and NRF2 genes increase susceptibility to cisplatin-induced ototoxicity: A preliminary study.

OBJECTIVE: The genotype-phenotype relationship in cisplatin-induced ototoxicity remains unclear. By assessing early shifts in distortion product otoacoustic emission (DPOAE) levels after initial cisplatin administration, we aimed to discriminate patients' susceptibility to cisplatin-induced ototoxicity and elucidate their genetic background. STUDY DESIGN: A prospective cross-sectional study. SETTING: Tertiary referral hospital in Japan. PATIENTS: Twenty-six patients with head and neck cancer were undergoing chemoradiotherapy with three cycles of 100 mg/m2 cisplatin. INTERVENTIONS: Repetitive pure-tone audiometry and DPOAE measurements, and blood sampling for DNA extraction were performed. Patients were grouped into early ototoxicity presence or absence based on whether DPOAE level shifts exceeded the corresponding reference limits of the 21-day test interval. MAIN OUTCOME MEASURES: Hearing thresholds after each cisplatin cycle, severity of other adverse events, and polymorphisms in cisplatin-induced ototoxicity-associated genes were compared. RESULTS: Early ototoxicity was present in 14 and absent in 12 patients. Ototoxicity presence on DPOAEs was associated with greater progression of hearing loss in frequencies ≥2 kHz throughout therapy and with higher ototoxicity grades compared with ototoxicity absence. Ototoxicity was further associated with grade ≥2 nausea. Ototoxicity presence was genetically associated with the GSTT1 null genotype and G-allele of NFE2L2 rs6721961, whereas ototoxicity absence was associated with the GSTM1 null genotype. Dose-dependent progression of hearing loss was the greatest in the combined genotype pattern of GSTT1 null and the T/G or G/G variants of rs6721961. CONCLUSION: Early DPOAE changes reflected genetic vulnerability to cisplatin-induced ototoxicity. Hereditary insufficiency of the antioxidant defense system causes severe cisplatin-induced hearing loss and nausea.

[Prediction of Cardiac Toxicity by Anti-cancer Drugs Using iPSC Cardiomyocytes].

Recent advances in cancer therapy have significantly improved the survival rate of patients with cancer. In contrast, anti-cancer drug-induced adverse effects, especially cardiotoxicity, have come to affect patients' prognosis and quality of life. Therefore, there is a growing need to understand the anti-cancer drug-induced cardiotoxicity. Human induced pluripotent stem (iPS) cell-derived cardiomyocytes (hiPSC-CMs) have been used to assess drug-induced cardiotoxicity by improving the predictability of clinical cardiotoxicity and the principles of the 3Rs (replacement, reduction and refinement). To predict the anti-cancer drug-induced cardiotoxicity, we developed a novel method to assess drug-induced proarrhythmia risk using hiPSC-CMs by participating in the international validation. In addition, we established the chronic contractility toxicity assessment by image-based motion analysis. The compound BMS-986094, which was withdrawn from clinical trials, inhibited contractility velocity and relaxation velocity in hiPSC-CMs. Currently, we are trying to investigate the predictability of the contractility assay by comparing the hiPSC-CM data with adverse events reports from real-world database. In this review, we would like to introduce the novel imaging-based contractility method using hiPSC-CMs and future perspectives in anti-cancer drug-induced cardiotoxicity.

Exploring the role of ghrelin and des-acyl ghrelin in chemotherapy-induced nausea and vomiting.

Ghrelin and its mimetics have been shown to reduce cisplatin-induced emesis in preclinical studies using ferrets and shrews. This study investigated the effectiveness of ghrelin and des-acyl ghrelin (DAG) in antagonizing cisplatin-induced emesis and physiological changes indicative of nausea in Suncus murinus. Animals implanted with radiotelemetry devices were administered ghrelin (0.2, 1.0, and 5.0 µg/day), DAG (0.2, 1.0, and 5.0 µg/day), or saline (14 µL/day) intracerebroventricularly 4 days before and 3 days after treatment with cisplatin (30 mg/kg). At the end, the anti-apoptotic potentials of ghrelin and DAG were assessed by measuring Bax expression and cytochrome C activity. Neurotransmitter changes in the brain were evaluated using liquid chromatography-mass spectrometry analysis. Ghrelin and DAG reduced cisplatin-induced emesis in the delayed (24-72 h) but not the acute phase (0-24 h) of emesis. Ghrelin also partially reversed the inhibitory effects of cisplatin on food intake without affecting gastrointestinal myoelectrical activity or causing hypothermia; however, ghrelin or DAG did not prevent these effects. Ghrelin and DAG could attenuate the cisplatin-induced upregulation of Bax and cytochrome C in the ileum. Cisplatin dysregulated neurotransmitter levels in the frontal cortex, amygdala, thalamus, hypothalamus, and brainstem, and this was partially restored by low doses of ghrelin and DAG. Our findings suggest that ghrelin and DAG exhibit protective effects against cisplatin-induced delayed emesis. The underlying antiemetic mechanism may involve GHSR and/or unspecified pathways that modulate the neurotransmitters involved in emesis control in the brain and an action to attenuate apoptosis in the gastrointestinal tract.

Inhibition of CISD1 attenuates cisplatin-induced hearing loss in mice via the PI3K and MAPK pathways.

Cisplatin is an effective chemotherapeutic drug for different cancers, but it also causes severe and permanent hearing loss. Oxidative stress and mitochondrial dysfunction in cochlear hair cells (HCs) have been shown to be important in the pathogenesis of cisplatin-induced hearing loss (CIHL). CDGSH iron sulfur domain 1 (CISD1, also known as mitoNEET) plays a critical role in mitochondrial oxidative capacity and cellular bioenergetics. Targeting CISD1 may improve mitochondrial function in various diseases. However, the role of CISD1 in cisplatin-induced ototoxicity is unclear. Therefore, this study was performed to assess the role of CISD1 in cisplatin-induced ototoxicity. We found that CISD1 expression was significantly increased after cisplatin treatment in both HEI-OC1 cells and cochlear HCs. Moreover, pharmacological inhibition of CISD1 with NL-1 inhibited cell apoptosis and reduced mitochondrial reactive oxygen species accumulation in HEI-OC1 cells and cochlear explants. Inhibition of CISD1 with small interfering RNA in HEI-OC1 cells had similar protective effects. Furthermore, NL-1 protected against CIHL in adult C57 mice, as evaluated by the auditory brainstem response and immunofluorescent staining. Mechanistically, RNA sequencing revealed that NL-1 attenuated CIHL via the PI3K and MAPK pathways. Most importantly, NL-1 did not interfere with the antitumor efficacy of cisplatin. In conclusion, our study revealed that targeting CISD1 with NL-1 reduced reactive oxygen species accumulation, mitochondrial dysfunction, and apoptosis via the PI3K and MAPK pathways in HEI-OC1 cell lines and mouse cochlear explants in vitro, and it protected against CIHL in adult C57 mice. Our study suggests that CISD1 may serve as a novel target for the prevention of CIHL.

Pharmacokinetic-toxicodynamic Modeling to Elucidate the Involvement of Dorsal Root Ganglion Neuron in Oxaliplatin-induced Peripheral Neuropathy.

BACKGROUND/AIM: Oxaliplatin (L-OHP)-induced peripheral neuropathy (OIPN) limits L-OHP dosage due to nerve cell damage in the dorsal root ganglion (DRG) caused by platinum (Pt). Despite various recommended approaches for OIPN management, no effective approach has been established. The aim of this study was to evaluate Pt distribution into DRG after repeat administrations of L-OHP in rats and to develop a pharmacokinetic-toxicodynamic (PK-TD) model using Pt concentrations in DRG to predict neuropathy severity. MATERIALS AND METHODS: Male Wistar rats were administered L-OHP (3, 5, or 8 mg/kg i.v.) once weekly. Blood and DRG samples were collected following L-OHP administration. For toxicodynamic (TD) study, OIPN was evaluated using the von Frey test. Plasma and DRG Pt concentrations and thresholds values in von Frey test were used for PK-TD modeling using Phoenix WinNonlin® version 8.3 software. RESULTS: Pt concentration in the DRG increased with repeated administration of L-OHP in a dose-dependent manner, indicating Pt accumulation in DRG following multiple administrations. The PK-TD model, consisting of an indirect response model and a transit compartment model with the DRG compartment, adequately described the temporal changes in OIPN with reliable TD parameters (≤36.4% with coefficient of variation). The maximum drug inhibition model could be employed to establish a quantitative correlation between the Pt content present in the DRG and the toxic potency resulting in OIPN. CONCLUSION: The utility of the PK-TD model for predicting neuropathy outcomes was established, suggesting that models composed of the DRG compartment contribute to determining an optimal dosing strategy for reducing OIPN.

Mechanism of DNA Intercalation by Chloroquine Provides Insights into Toxicity.

Chloroquine has been used as a potent antimalarial, anticancer drug, and prophylactic. While chloroquine is known to interact with DNA, the details of DNA-ligand interactions have remained unclear. Here we characterize chloroquine-double-stranded DNA binding with four complementary approaches, including optical tweezers, atomic force microscopy, duplex DNA melting measurements, and isothermal titration calorimetry. We show that chloroquine intercalates into double stranded DNA (dsDNA) with a KD ~ 200 µM, and this binding is entropically driven. We propose that chloroquine-induced dsDNA intercalation, which happens in the same concentration range as its observed toxic effects on cells, is responsible for the drug's cytotoxicity.

Analysis of the contributing role of drug transport across biological barriers in the development and treatment of chemotherapy-induced peripheral neuropathy.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) represents a major unmet medical need that currently has no preventive and/or curative treatment. This is, among others, driven by a poor understanding of the contributive role of drug transport across biological barriers to target-site exposure. METHODS: Here, we systematically investigated the transport of 11 small-molecule drugs, both, associated and not with CIPN development, at conventional (dorsal root ganglia, sciatic nerve) and non-conventional (brain, spinal cord, skeletal muscle) CIPN sites. We developed a Combinatory Mapping Approach for CIPN, CMA-CIPN, combining in vivo and in vitro elements. RESULTS: Using CMA-CIPN, we determined the unbound tissue-to-plasma concentration ratio (Kp,uu) and the unbound intracellular-to-extracellular concentration ratio (Kp,uu,cell), to quantitatively assess the extent of unbound drug transport across endothelial interfaces and parenchymal cellular barriers of investigated CIPN-sites, respectively, in a rat model. The analysis revealed that unique pharmacokinetic characteristics underly time-dependent accumulation of the CIPN-positive drugs paclitaxel and vincristine at conventional (dorsal root ganglia and sciatic nerve) and non-conventional (skeletal muscle) CIPN sites. Investigated CIPN-positive drugs displayed intracellular accumulation contrary to CIPN-negative drugs nilotinib and methotrexate, which lacked this feature in all investigated tissues. CONCLUSIONS: Hence, high unbound drug intracellular and extracellular exposure at target sites, driven by an interplay of drug transport across the endothelial and parenchymal cellular barriers, is a predisposing factor to CIPN development for CIPN-positive drugs. Critical drug-specific features of unbound drug disposition at various CIPN- sites provide invaluable insights into understanding the pharmacological/toxicological effects at the target-sites which will inform new strategies for monitoring and treatment of CIPN.

Dihydroartemisinin abolishes cisplatin-induced nephrotoxicity in vivo.

Dihydroartemisinin (DHA), a derivative of artemisinin which is primarily used to treat malaria in clinic, also confers protective effect on lipopolysaccharide-induced nephrotoxicity. While, the activities of DHA in cisplatin (CDDP)-caused nephrotoxicity are elusive. To investigate the role and underlying mechanism of DHA in CDDP-induced nephrotoxicity. Mice were randomly separated into four groups: normal, CDDP, and DHA (25 and 50 mg/kg were orally injected 1 h before CDDP for consecutive 10 days). All mice except the normal were single injected intraperitoneally with CDDP (22 mg/kg) for once on the 7th day. Combined with quantitative proteomics and bioinformatics analysis, the impact of DHA on renal cell apoptosis, oxidative stress, biochemical indexes, and inflammation in mice were investigated. Moreover, a human hepatocellular carcinoma cells xenograft model was established to elucidate the impact of DHA on tumor-related effects of CDDP. DHA reduced the levels of creatinine (CREA) (p < 0.01) and blood urea nitrogen (BUN) (p < 0.01), reversed CDDP-induced oxidative, inflammatory, and apoptosis indexes (p < 0.01). Mechanistically, DHA attenuated CDDP-induced inflammation by inhibiting nuclear factor κB p65 (NFκB p65) expression, and suppressed CDDP-induced renal cell apoptosis by inhibiting p63-mediated endogenous and exogenous apoptosis pathways. Additionally, DHA alone significantly decreased the tumor weight and did not destroy the antitumor effect of CDDP, and did not impact AST and ALT. In conclusion, DHA prevents CDDP-triggered nephrotoxicity via reducing inflammation, oxidative stress, and apoptosis. The mechanisms refer to inhibiting NFκB p65-regulated inflammation and alleviating p63-mediated mitochondrial endogenous and Fas death receptor exogenous apoptosis pathway.

Protective effect of alpha-lipoic acid and epalrestat on oxaliplatin-induced peripheral neuropathy in zebrafish.

INTRODUCTION/AIMS: Oxaliplatin is a platinum-based anti-cancer drug widely used in colorectal cancer patients, but it may cause peripheral neuropathy. As one of the main causes of oxaliplatin-induced peripheral neuropathy (OPN) is oxidative stress, which is also a key factor causing diabetic peripheral neuropathy (DPN), the aim of this study was to evaluate the preventive effects of alpha-lipoic acid (ALA) and epalrestat (EP), which are used for the treatment of DPN, in an OPN zebrafish model. METHODS: Tg(nbt:dsred) transgenic zebrafish, with sensory nerves in the peripheral lateral line, were treated with oxaliplatin, oxaliplatin/EP, and oxaliplatin/ALA for 4 days. A confocal microscope was used to visualize and quantify the number of axon bifurcations in the distal nerve ending. To analyze the formation of synapses on sensory nerve terminals, quantification of membrane-associated guanylate kinase (MAGUK) puncta was performed using immunohistochemistry. RESULTS: The number of axon bifurcations and intensity of MAGUK puncta were significantly reduced in the oxaliplatin-treated group compared with those in the embryo medium-treated group. In both the oxaliplatin/EP and oxaliplatin/ALA-treated groups, the number of axon bifurcations and intensity of MAGUK puncta were greater than those in the oxaliplatin-treated group (p < .0001), and no significant difference was observed between larvae treated with oxaliplatin/ALA 1 µM and oxaliplatin/EP 1 µM (p = .4292). DISCUSSION: ALA and EP have protective effects against OPN in zebrafish. Our findings show that ALA and EP can facilitate more beneficial treatment for OPN.

Pegylated nanoliposomal cisplatin ameliorates chemotherapy-induced peripheral neuropathy.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a serious adverse effect of cisplatin. The current study aimed to determine whether PEGylated nanoliposomal cisplatin can limit CIPN in an animal model. METHODS: Cisplatin-loaded PEGylated liposome nanoparticles (Cis-PL) were produced as a combination of lecithin, cholesterol, and DSPE-mPEG2000 in a molar ratio of 50:45:5 and were characterized by polydispersity index (PDI), zeta potential, Field emission scanning electron microscopy (FESEM) analysis, as well as encapsulation efficiency (EE). Fifteen male rats were provided and randomly divided into 3 groups including Cis-PL group, cisplatin group, and control group. Behavioural tests (hot-plate test and acetone drop test) were used for evaluating CIPN. Moreover, oxidative stress markers and histopathological analysis were applied. Treatment-related toxicity was assessed by haematological analysis as well as liver and renal function tests. RESULTS: Cis-PL had an average particle size of 125.4, PDI of 0.127, and zeta potential of -40.9 mV. Moreover, the Cis-PL exhibited a high EE as well as low levels of leakage rate at 25 °C. In a hot-plate test, paw withdrawal latency was longer in Cis-PL group in comparison to rats treated with cisplatin. A lower number of withdrawal responses was detected during acetone drop test in Cis-PL group than in cisplatin-treated rats. Assessment of oxidative stress markers showed that Cis-PL could improve oxidative stress. Additionally, histopathological assessment demonstrated that the number of satellite cells was significantly reduced in the dorsal root ganglion (DRG) of Cis-PL-treated rats compared with those treated with cisplatin. The cisplatin group had elevated white blood cells counts, reduced platelet counts, and higher levels of bilirubin, ALT (alanine aminotransferase, and AST (aspartate aminotransferase), and creatinine compared with the control group, which was ameliorated in Cis-PL group. CONCLUSIONS: Data from the current study support the previous hypothesis that Cisplatin-loaded PEGylated liposome could be a promising solution for CIPN in the future by modulating oxidative stress and preventing glial cell activation in DRG, suggesting further clinical studies to investigate the efficacy of this agent and its potential application in clinical practice.

Cisplatin Provokes Peripheral Nociception and Neuronal Features of Therapy-Induced Senescence and Calcium Dysregulation in Rats.

Therapy-Induced Senescence (TIS) is a form of senescence that is typically described in malignant cells in response to the exposure of cancer chemotherapy or radiation but can also be precipitated in non-malignant cells. TIS has been shown to contribute to the development of several cancer therapy-related adverse effects; however, evidence on its role in mediating chemotherapy-induced neurotoxicity, such as Chemotherapy-induced Peripheral Neuropathy (CIPN), is limited. We here show that cisplatin treatment over two cycles (cumulative dose of 23 mg/kg) provoked mechanical allodynia and thermal hyperalgesia in Sprague-Dawley rats. Isolation of dorsal root ganglia (DRG) from the cisplatin-treated rats demonstrated robust SA-ß-gal upregulation at both day 8 (after the first cycle) and day 18 (after the second cycle), decreased lmnb1 expression, increased expression of cdkn1a and cdkn2a, and of several factors of the Senescence-associated Secretory Phenotype (SASP) (Il6, Il1b, and mmp9). Moreover, single-cell calcium imaging of cultured DRGs revealed a significant increase in terms of the magnitude of KCl-evoked calcium responses in cisplatin-treated rats compared to vehicle-treated rats. No significant change was observed in terms of the magnitude of capsaicin-evoked calcium responses in cisplatin-treated rats compared to vehicle-treated rats but with decreased area under the curve of the responses in cisplatin-treated rats. Further evidence to support the contribution of TIS to therapy adverse effects is required but should encourage the use of senescence-modulating agents (senotherapeutics) as novel palliative approaches to mitigate chemotherapy-induced neurotoxicity.

Sodium thiosulfate does not protect ovarian reserve from cisplatin-induced gonadotoxicity†.

Cisplatin, a platinum-containing alkylating agent, is used in the treatment of various tumors owing to its potent antitumor activity. However, it causes permanent and adverse effects, particularly hearing loss and depletion of ovarian reserve. Until recently, there were no clinically available protective agents to mitigate the adverse side effects of cisplatin-induced cytotoxicity. In 2022, sodium thiosulfate (STS) was approved by the Food and Drug Administration for mitigating hearing loss in children and adolescents undergoing cisplatin treatment. Consequently, our investigation aimed to determine if STS could protect ovarian reserve against cisplatin-induced gonadotoxicity. In an ex vivo culture, the cisplatin-only group exhibited a loss of primordial follicles, while post-STS administration after cisplatin exposure effectively protected primordial follicles. However, when post-STS was administrated either 6 or 4 h after cisplatin exposure, it did not confer protection against cisplatin-induced gonadotoxicity in postnatal day 7 or adolescent mouse models. Immunofluorescence assays using γH2AX and cPARP revealed that oocytes within primordial follicles exhibited DNA damage after cisplatin exposure, irrespective of post-STS administration. This underscores the rapid and heightened sensitivity of oocytes to gonadotoxicity. In addition, oocytes demonstrated an increased expression of pCHK2 rather than pERK, suggesting that the pathway leading to oocyte death differs from the pathway observed in the inner ear cell death following cisplatin exposure. These results imply that while the administration of STS after cisplatin is highly beneficial in preventing hearing loss, it does not confer a protective effect on the ovaries in mouse models.

Otoprotection against aminoglycoside- and cisplatin-induced ototoxicity focusing on the upstream drug uptake pathway.

Aminoglycoside- and cisplatin-induced ototoxicity, which is a significant issue owing to the widespread use of these drugs in clinical practice, involves the entry of aminoglycosides and cisplatin into the endolymph and hair cells via specific channels or transporters, followed by reactive oxygen species (ROS) generation and hair cells apoptosis. Current strategies focalize primarily on interference with downstream ROS effects; however, recent evidence has demonstrated that inhibiting the uptake of aminoglycosides and cisplatin by hair cells is another promising strategy for tackling the upstream drug uptake pathway. With advances in structural biology, the conformations of certain aminoglycoside and cisplatin channels and transporters, such as the mechanoelectrical transduction channel and organic cation transporter-2, have been largely elucidated. These channels and transporters may become potential targets for the introduction of new otoprotective strategies. This review focuses on the strategies for inhibiting ototoxic drugs uptake by auditory hair cells and provides potential targets for recent developments in the field of otoprotection. Molecular dynamics (MD) simulations of these proteins could help identify the molecules that inhibit the uptake of aminoglycosides and cisplatin by hair cells. Integrating upstream drug uptake pathway targets and MD simulations may help dissect molecular mechanisms and develop novel otoprotective strategies for aminoglycoside- and cisplatin-induced ototoxicity.

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.

Morphofunctional characterisation of axonal damage in different rat models of chemotherapy-induced peripheral neurotoxicity: The role of nerve excitability testing.

BACKGROUND AND AIMS: Chemotherapy-induced peripheral neurotoxicity (CIPN) is a common and long-lasting adverse event of several anticancer compounds, for which treatment has not yet been developed. To fill this gap, preclinical studies are warranted, exploiting highly translational outcome measure(s) to transfer data from bench to bedside. Nerve excitability testing (NET) enables to test in vivo axonal properties and can be used to monitor early changes leading to axonal damage. METHODS: We tested NET use in two different CIPN rat models: oxaliplatin (OHP) and paclitaxel (PTX). Animals (female) were chronically treated with either PTX or OHP and compared to respective control animals. NET was performed as soon as the first injection was administered. At the end of the treatment, CIPN onset was verified via a multimodal and robust approach: nerve conduction studies, nerve morphometry, behavioural tests and intraepidermal nerve fibre density. RESULTS: NET showed the typical pattern of axonal hyperexcitability in the 72 h following the first OHP administration, whereas it showed precocious signs of axonal damage in PTX animals. At the end of the month of treatment, OHP animals showed a pattern compatible with a mild axonal sensory polyneuropathy. Instead, PTX cohort was characterised by a rather severe sensory axonal polyneuropathy with minor signs of motor involvement. INTERPRETATION: NET after the first administration demonstrated the ongoing OHP-related channelopathy, whereas in PTX cohort it showed precocious signs of axonal damage. Therefore, NET could be suggested as an early surrogate marker in clinical trials, to detect precocious changes leading to axonal damage.

Identification of Novel and Early Biomarkers for Cisplatin-induced Nephrotoxicity and the Nephroprotective Role of Cimetidine using a Pharmacometabolomic-based Approach Coupled with In Vitro Toxicodynamic Modeling and Simulation.

Cisplatin is widely used for the treatment of various types of cancer. However, cisplatin-induced nephrotoxicity (CIN) is frequently observed in patients receiving cisplatin therapy which poses a challenge in its clinical utility. Currently used clinical biomarkers for CIN are not adequate for early detection of nephrotoxicity, hence there is a need to identify potential early biomarkers in predicting CIN. In the current study, a combination of in vitro toxicodynamic (TD) modeling and untargeted global metabolomics approach was used to identify novel potential metabolite biomarkers for early detection of CIN. In addition, we investigated the protective role of cimetidine (CIM), an inhibitor of the organic cation transporter 2 (OCT2), in suppressing CIN. We first characterized the time-course of nephrotoxic effects of cisplatin (CIS) and the protective effects of CIM in a human pseudo-immortalized renal proximal tubule epithelial cell line (RPTEC), SA7K cell line. Secondly, we used a mathematical cell-level, in vitro TD modeling approach to quantitatively characterize the time-course effects of CIS and CIM as single agents and combination in SA7K cells. Based on the experimental and modeling results, we selected relevant concentrations of CIS and CIM for our metabolomics study. With the help of PCA (Principal Component Analysis) and PLS-DA (Projection to Latent Structure - Discriminate Analysis) analyses, we confirmed global metabolome changes for different groups (CIS, CIM, CIS+CIM vs control) in SA7K cells. Based on the criterion of a p-value ≤ 0.05 and a fold change ≥ 2 or ≤ 0.5, we identified 20 top metabolites that were significantly changed during the early phase i.e. within first 12 h of CIS treatment. Finally, pathway analysis was conducted that revealed the key metabolic pathways that were most impacted in CIN.

Cinchonine and cinchonidine alleviate cisplatin-induced ototoxicity by regulating PI3K-AKT signaling.

AIM: Cinchonine (CN) and its isomer cinchonidine (CD), two of the common cinchona alkaloids, are wildly used as antimalarial drugs. However, the effects of CN and CD on the auditory system are unknown. METHODS: Molecular docking and molecular dynamics (MD) simulation were used for predicting effective drugs. The CCK-8 assay was conducted for assessing cell viability in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells. MitoSox Red staining revealed reactive oxygen species (ROS) amounts. TMRM staining was used to assess the mitochondrial membrane potential (ΔΨm). Immunofluorescence staining of myosin 7a was used to examine hair cells (HCs) in cisplatin-treated neonatal mouse cochlear explants, while TUJ-1 immunostaining was used for the detection of spiral ganglion neurons (SGNs). Cleaved caspase-3 and TUNEL immunostaining were utilized for apoptosis assessment. Immunoblot was carried out to detect PI3K-AKT signaling effectors. RESULTS: Pretreatment with CN or CD significantly increased cell viability and reduced mitochondrial dysfunction and ROS accumulation in cisplatin-treated HEI-OC1 cells. Immunofluorescent staining of cochlear explants showed that CN and CD attenuated cisplatin-induced damage to SGNs and HCs. Immunoblot revealed that CN and CD downregulated the expression of cleaved caspase-3 and activated PI3K-AKT signaling in cisplatin-injured HEI-OC1 cells. CONCLUSION: CD and CN can reduce ototoxicity caused by cisplatin and might help treat cisplatin-associated hearing loss.