Membrane transporters as mediators of Cisplatin effects and side effects

Autophagy-mediated ID1 turnover dictates chemo-resistant fate in ovarian cancer stem cells

BACKGROUND

The mechanisms enabling dynamic shifts between drug-resistant and drug-sensitive states in cancer cells are still underexplored. This study investigated the role of targeted autophagic protein degradation in regulating ovarian cancer stem cell (CSC) fate decisions and chemo-resistance.

METHODS

Autophagy levels were compared between CSC-enriched side population (SP) and non-SP cells (NSP) in multiple ovarian cancer cell lines using immunoblotting, immunofluorescence, and transmission electron microscopy. The impact of autophagy modulation on CSC markers and differentiation was assessed by flow cytometry, immunoblotting and qRT-PCR. In silico modeling and co-immunoprecipitation identified ID1 interacting proteins. Pharmacological and genetic approaches along with Annexin-PI assay, ChIP assay, western blotting, qRT-PCR and ICP-MS were used to evaluate effects on cisplatin sensitivity, apoptosis, SLC31A1 expression, promoter binding, and intracellular platinum accumulation in ID1 depleted backdrop. Patient-derived tumor spheroids were analyzed for autophagy and SLC31A1 levels.

RESULTS

Ovarian CSCs exhibited increased basal autophagy compared to non-CSCs. Further autophagy stimulation by serum-starvation and chemical modes triggered proteolysis of the stemness regulator ID1, driving the differentiation of chemo-resistant CSCs into chemo-sensitive non-CSCs. In silico modeling predicted TCF12 as a potent ID1 interactor, which was validated by co-immunoprecipitation. ID1 depletion freed TCF12 to transactivate the cisplatin influx transporter SLC31A1, increasing intracellular cisplatin levels and cytotoxicity. Patient-derived tumor spheroids exhibited a functional association between autophagy, ID1, SLC31A1, and platinum sensitivity.

CONCLUSIONS

This study reveals a novel autophagy-ID1-TCF12-SLC31A1 axis where targeted autophagic degradation of ID1 enables rapid remodeling of CSCs to reverse chemo-resistance. Modulating this pathway could counter drug resistance in ovarian cancer.

Molecular Characteristics of Cisplatin-Induced Ototoxicity and Therapeutic Interventions

Cisplatin is a commonly used chemotherapeutic agent with proven efficacy in treating various malignancies, including testicular, ovarian, cervical, breast, bladder, head and neck, and lung cancer. Cisplatin is also used to treat tumors in children, such as neuroblastoma, osteosarcoma, and hepatoblastoma. However, its clinical use is limited by severe side effects, including ototoxicity, nephrotoxicity, neurotoxicity, hepatotoxicity, gastrointestinal toxicity, and retinal toxicity. Cisplatin-induced ototoxicity manifests as irreversible, bilateral, high-frequency sensorineural hearing loss in 40-60% of adults and in up to 60% of children. Hearing loss can lead to social isolation, depression, and cognitive decline in adults, and speech and language developmental delays in children. Cisplatin causes hair cell death by forming DNA adducts, mitochondrial dysfunction, oxidative stress, and inflammation, culminating in programmed cell death by apoptosis, necroptosis, pyroptosis, or ferroptosis. Contemporary medical interventions for cisplatin ototoxicity are limited to prosthetic devices, such as hearing aids, but these have significant limitations because the cochlea remains damaged. Recently, the U.S. Food and Drug Administration (FDA) approved the first therapy, sodium thiosulfate, to prevent cisplatin-induced hearing loss in pediatric patients with localized, non-metastatic solid tumors. Other pharmacological treatments for cisplatin ototoxicity are in various stages of preclinical and clinical development. This narrative review aims to highlight the molecular mechanisms involved in cisplatin-induced ototoxicity, focusing on cochlear inflammation, and shed light on potential antioxidant and anti-inflammatory therapeutic interventions to prevent or mitigate the ototoxic effects of cisplatin. We conducted a comprehensive literature search (Google Scholar, PubMed) focusing on publications in the last five years.

Long-term viable chimeric nephrons generated from progenitor cells are a reliable model in cisplatin-induced toxicity

Kidney organoids have shown promise as evaluation tools, but their in vitro maturity remains limited. Transplantation into adult mice has aided in maturation; however, their lack of urinary tract connection limits long-term viability. Thus, long-term viable generated nephrons have not been demonstrated. In this study, we present an approachable method in which mouse and rat renal progenitor cells are injected into the developing kidneys of neonatal mice, resulting in the generation of chimeric nephrons integrated with the host urinary tracts. These chimeric nephrons exhibit similar maturation to the host nephrons, long-term viability with excretion and reabsorption functions, and cisplatin-induced renal injury in both acute and chronic phases, as confirmed by single-cell RNA-sequencing. Additionally, induced human nephron progenitor cells differentiate into nephrons within the neonatal kidneys. Collectively, neonatal injection represents a promising approach for in vivo nephron generation, with potential applications in kidney regeneration, drug screening, and pathological analysis.

Insights into Repeated Renal Injury Using RNA-Seq with Two New RPTEC Cell Lines

Renal proximal tubule epithelial cells (RPTECs) are a primary site for kidney injury. We created two RPTEC lines from CD-1 mice immortalized with hTERT (human telomerase reverse transcriptase) or SV40 LgT antigen (Simian Virus 40 Large T antigen). Our hypothesis was that low-level, repeated exposure to subcytotoxic levels of 0.25-2.5 μM cisplatin (CisPt) or 12.5-100 μM aflatoxin B1 (AFB1) would activate distinctive genes and pathways in these two differently immortalized cell lines. RNA-seq showed only LgT cells responded to AFB1 with 1139 differentially expressed genes (DEGs) at 72 h. The data suggested that AFB1 had direct nephrotoxic properties on the LgT cells. However, both the cell lines responded to 2.5 μM CisPt from 3 to 96 h expressing 2000-5000 total DEGs. For CisPt, the findings indicated a coordinated transcriptional program of injury signals and repair from the expression of immune receptors with cytokine and chemokine secretion for leukocyte recruitment; robust expression of synaptic and substrate adhesion molecules (SAMs) facilitating the expression of neural and hormonal receptors, ion channels/transporters, and trophic factors; and the expression of nephrogenesis transcription factors. Pathway analysis supported the concept of a renal repair transcriptome. In summary, these cell lines provide in vitro models for the improved understanding of repeated renal injury and repair mechanisms. High-throughput screening against toxicant libraries should provide a wider perspective of their capabilities in nephrotoxicity.

Dysregulation and Epigenetic Reprogramming of NRF2 Signaling Axis Promote Acquisition of Cisplatin Resistance and Metastasis in Head and Neck Squamous Cell Carcinoma

PURPOSE

Cisplatin (CDDP)-based chemotherapy is a first-line treatment for patients with advanced head and neck squamous cell carcinomas (HNSCC), despite a high rate of treatment failures, acquired resistance, and subsequent aggressive behavior. The purpose of this study was to study the mechanism of CDDP resistance and metastasis in HNSCC. We investigated the role of NRF2 pathway activation as a driven event for tumor progression and metastasis of HNSCC.

EXPERIMENTAL DESIGN

Human HNSCC cell lines that are highly resistant to CDDP were generated. Clonogenic survival assays and a mouse model of oral cancer were used to examine the impact of NRF2 activation in vitro and in vivo on CDDP sensitivity and development of metastasis. Western blotting, immunostaining, whole-exome sequencing, single-cell transcriptomic and epigenomic profiling platforms were performed to dissect clonal evolution and molecular mechanisms.

RESULTS

Implantation of CDDP-resistant HNSCC cells into the tongues of nude mice resulted in a very high rate of distant metastases. The CDDP-resistant cells had significantly higher expression of NRF2 pathway genes in the presence of newly acquired KEAP1 mutations, or via epigenomic activation of target genes. Knockdown of NRF2 or restoration of the wild-type KEAP1 genes resensitized resistant cells to CDDP and decreased distant metastasis (DM). Finally, treatment with inhibitor of glutaminase-1, a NRF2 target gene, alleviated CDDP resistance.

CONCLUSIONS

CDDP resistance and development of DM are associated with dysregulated and epigenetically reprogrammed KEAP1-NRF2 signaling pathway. A strategy targeting KEAP1/NRF2 pathway or glutamine metabolism deserves further clinical investigation in patients with CDDP-resistant head and neck tumors.

Novel Platinum(II) and Platinum(IV) Antitumor Agents that Exhibit Potent Cytotoxicity and Selectivity

A novel platinum(II) complex 47OMESS(II) and its platinum(IV) derivative 47OMESS(IV) were synthesized and characterized. Cytotoxicity studies against mesenchymal cells (MCs) and lung (A549), breast (MDA-MB-231), and melanoma (A375) cancer cells demonstrated 7-20-fold superior activity for both complexes relative to cisplatin. Remarkably, 47OMESS(IV) demonstrated 17-22-fold greater selectivity toward the cancerous cells compared to the non-cancerous MCs. Western blot analysis on A549 cells showed the involvement of the intrinsic apoptotic pathway. Cellular fractionation and uptake experiments in A549 cells using ICP-mass spectrometry (MS) indicated that 47OMESS(II) and 47OMESS(IV) cross the cellular membrane predominantly via active transport mechanisms. The significant improvement in selectivity that is exhibited by 47OMESS(IV) is reported for the first time for this class of complexes.

Functional Evaluation and Nephrotoxicity Assessment of Human Renal Proximal Tubule Cells on a Chip

An in vitro human renal proximal tubule model that represents the proper transporter expression and pronounced epithelial polarization is necessary for the accurate prediction of nephrotoxicity. Here, we constructed a high-throughput human renal proximal tubule model based on an integrated biomimetic array chip (iBAC). Primary human renal proximal tubule epithelial cells (hRPTECs) cultured on this microfluidic platform were able to form a tighter barrier, better transporter function and more sensitive nephrotoxicity prediction than those on the static Transwell. Compared with the human immortalized HK2 model, the hRPTECs model on the chip gained improved apical-basolateral polarization, barrier function and transporter expression. Polymyxin B could induce nephrotoxicity not only from the apical of the hRPTECs, but also from the basolateral side on the iBAC. However, other chemotherapeutic agents, such as doxorubicin and sunitinib, only induced nephrotoxicity from the apical surface of the hRPTECs on the iBAC. In summary, our renal proximal tubule model on the chip exhibits improved epithelial polarization and membrane transporter activity, and can be implemented as an effective nephrotoxicity-screening toolkit.

Cellular landscaping of cisplatin resistance in cervical cancer

Cervical cancer (CC) caused by human papillomavirus (HPV) is one of the largest causes of malignancies in women worldwide. Cisplatin is one of the widely used drugs for the treatment of CC is rendered ineffective owing to drug resistance. This review highlights the cause of resistance and the mechanism of cisplatin resistance cells in CC to develop therapeutic ventures and strategies that could be utilized to overcome the aforementioned issue. These strategies would include the application of nanocarries, miRNA, CRIPSR/Cas system, and chemotherapeutics in synergy with cisplatin to not only overcome the issues of drug resistance but also enhance its anti-cancer efficiency. Moreover, we have also discussed the signaling network of cisplatin resistance cells in CC that would provide insights to develop therapeutic target sites and inhibitors. Furthermore, we have discussed the role of CC metabolism on cisplatin resistance cells and the physical and biological factors affecting the tumor microenvironments.

Oocyte CTR1 is not essential for cisplatin-induced oocyte death of primordial follicle

Accumulated evidence indicates that cisplatin, a platinum-based alkylating agent, causes preferential DNA damage to oocytes of primordial follicles (PFs) in the ovary, suggesting oocyte-favored accumulation of cisplatin. Copper transporter 1 (CTR1; Slc31a1 ) is implicated in facilitating cisplatin uptake in cells. Here we found that oocytes of PFs had constitutively higher expression of CTR1 than other cell types in mouse ovary. However, oocyte-specific Slc31a1 knockout was not sufficient to prevent cisplatin-induced depletion of PFs in vitro . Our data indicate that CTR1 would not be the only route for cisplatin to be transported inside the oocytes of PFs in the ovary.

Nimodipine Treatment Protects Auditory Hair Cells from Cisplatin-Induced Cell Death Accompanied by Upregulation of LMO4

Ototoxicity is one of the main dose-limiting side effects of cisplatin chemotherapy and impairs the quality of life of tumor patients dramatically. Since there is currently no established standard therapy targeting hearing loss in cisplatin treatment, the aim of this study was to investigate the effect of nimodipine and its role in cell survival in cisplatin-associated hearing cell damage. To determine the cytotoxic effect, the cell death rate was measured using undifferentiated and differentiated UB/OC−1 and UB/OC−2 cells, after nimodipine pre-treatment and stress induction by cisplatin. Furthermore, immunoblot analysis and intracellular calcium measurement were performed to investigate anti-apoptotic signaling, which was associated with a reduced cytotoxic effect after nimodipine pre-treatment. Cisplatin’s cytotoxic effect was significantly attenuated by nimodipine up to 61%. In addition, nimodipine pre-treatment counteracted the reduction in LIM Domain Only 4 (LMO4) by cisplatin, which was associated with increased activation of Ak strain transforming/protein kinase B (Akt), cAMP response element-binding protein (CREB), and signal transducers and activators of transcription 3 (Stat3). Thus, nimodipine presents a potentially well-tolerated substance against the ototoxicity of cisplatin, which could result in a significant improvement in patients’ quality of life.

Transporters and Toxicity: Insights from the International Transporter Consortium Workshop 4

Over the last decade, significant progress been made in elucidating the role of membrane transporters in altering drug disposition, with important toxicological consequences due to changes in localized concentrations of compounds. The topic of "Transporters and Toxicity" was recently highlighted as a scientific session at the International Transporter Consortium (ITC) Workshop 4 in 2021. The current white paper is not intended to be an extensive review on the topic of transporters and toxicity but an opportunity to highlight aspects of the role of transporters in various toxicities with clinically relevant implications as covered during the session. This includes a review of the role of solute carrier transporters in anticancer drug-induced organ injury, transporters as key players in organ barrier function, and the role of transporters in metal/metalloid toxicity.

Chemotherapy Side-Effects: Not All DNA Damage Is Equal

Recent advances have increased survival rates of children and adults suffering from cancer thanks to effective anti-cancer therapy, such as chemotherapy. However, during treatment and later in life they are frequently confronted with the severe negative side-effects of their life-saving treatment. The occurrence of numerous features of accelerated aging, seriously affecting quality of life, has now become one of the most pressing problems associated with (pediatric) cancer treatment. Chemotherapies frequently target and damage the DNA, causing mutations or genome instability, a major hallmark of both cancer and aging. However, there are numerous types of chemotherapeutic drugs that are genotoxic and interfere with DNA metabolism in different ways, each with their own biodistribution, kinetics, and biological fate. Depending on the type of DNA lesion produced (e.g., interference with DNA replication or RNA transcription), the organ or cell type inflicted (e.g., cell cycle or differentiation status, metabolic state, activity of clearance and detoxification mechanisms, the cellular condition or micro-environment), and the degree of exposure, outcomes of cancer treatment can largely differ. These considerations provide a conceptual framework in which different classes of chemotherapeutics contribute to the development of toxicities and accelerated aging of different organ systems. Here, we summarize frequently observed side-effects in (pediatric) ex-cancer patients and discuss which types of DNA damage might be responsible.

Comparison of Anticancer Drug Toxicities: Paradigm Shift in Adverse Effect Profile

The inception of cancer treatment with chemotherapeutics began in the 1940s with nitrogen mustards that were initially employed as weapons in World War II. Since then, treatment options for different malignancies have evolved over the period of last seventy years. Until the late 1990s, all the chemotherapeutic agents were small molecule chemicals with a highly nonspecific and severe toxicity spectrum. With the landmark approval of rituximab in 1997, a new horizon has opened up for numerous therapeutic antibodies in solid and hematological cancers. Although this transition to large molecules improved the survival and quality of life of cancer patients, this has also coincided with the change in adverse effect patterns. Typically, the anticancer agents are fraught with multifarious adverse effects that negatively impact different organs of cancer patients, which ultimately aggravate their sufferings. In contrast to the small molecules, anticancer antibodies are more targeted toward cancer signaling pathways and exhibit fewer side effects than traditional small molecule chemotherapy treatments. Nevertheless, the interference with the immune system triggers serious inflammation- and infection-related adverse effects. The differences in drug disposition and interaction with human basal pathways contribute to this paradigm shift in adverse effect profile. It is critical that healthcare team members gain a thorough insight of the adverse effect differences between the agents discovered during the last twenty-five years and before. In this review, we summarized the general mechanisms and adverse effects of small and large molecule anticancer drugs that would further our understanding on the toxicity patterns of chemotherapeutic regimens.

Panduratin A Derivative Protects against Cisplatin-Induced Apoptosis of Renal Proximal Tubular Cells and Kidney Injury in Mice

BACKGROUND

Panduratin A is a bioactive cyclohexanyl chalcone exhibiting several pharmacological activities, such as anti-inflammatory, anti-oxidative, and anti-cancer activities. Recently, the nephroprotective effect of panduratin A in cisplatin (CDDP) treatment was revealed. The present study examined the potential of certain compounds derived from panduratin A to protect against CDDP-induced nephrotoxicity.

METHODS

Three derivatives of panduratin A (DD-217, DD-218, and DD-219) were semi-synthesized from panduratin A. We investigated the effects and corresponding mechanisms of the derivatives of panduratin A for preventing nephrotoxicity of CDDP in both immortalized human renal proximal tubular cells (RPTEC/TERT1 cells) and mice.

RESULTS

Treating the cell with 10 µM panduratin A significantly reduced the viability of RPTEC/TERT1 cells compared to control (panduratin A: 72% ± 4.85%). Interestingly, DD-217, DD-218, and DD-219 at the same concentration did not significantly affect cell viability (92% ± 8.44%, 90% ± 7.50%, and 87 ± 5.2%, respectively). Among those derivatives, DD-218 exhibited the most protective effect against CDDP-induced renal proximal tubular cell apoptosis (control: 57% ± 1.23%; DD-218: 19% ± 10.14%; DD-219: 33% ± 14.06%). The cytoprotective effect of DD-218 was mediated via decreases in CDDP-induced mitochondria dysfunction, intracellular reactive oxygen species (ROS) generation, activation of ERK1/2, and cleaved-caspase 3 and 7. In addition, DD-218 attenuated CDDP-induced nephrotoxicity by a decrease in renal injury and improved in renal dysfunction in C57BL/6 mice. Importantly, DD-218 did not attenuate the anti-cancer efficacy of CDDP in non-small-cell lung cancer cells or colon cancer cells.

CONCLUSIONS

This finding suggests that DD-218, a derivative of panduratin A, holds promise as an adjuvant therapy in patients receiving CDDP.

Possible protective effect of pantoprazole against cisplatin-induced nephrotoxicity in head and neck cancer patients: a randomized controlled trial

Cisplatin is used to treat solid malignancies including head and neck cancer. However, nephrotoxicity limits its use. In this study, we looked for a possible protective effect of pantoprazole against cisplatin-induced nephrotoxicity. We used novel biomarkers for early detection of nephrotoxicity. Sixty chemotherapy naïve head and neck cancer patients completed the study. Following complete history taking and thorough clinical examination, patients were randomly divided into three groups: 20 patients in each. Group I (control group) received cisplatin without pantoprazole, groups II and III received pantoprazole 80 mg and 40 mg, respectively, concurrently with cisplatin. Blood and urine samples were collected at baseline, and 48 h after the first and third cycles of cisplatin administration. Assessment of serum creatinine and soluble FasL (sFasL), as well as urinary neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) was performed. Nephrotoxicity was detected in 6 patients in group I, none in group II and 3 patients in group III. Serum creatinine significantly increased at the end of treatment in group I compared to groups II and III. Group I also had significantly higher urinary KIM-1 and NGAL and serum sFasL compared to groups II and III after the first and third cycles. On the contrary, there was no significant difference between groups II and III. Pantoprazole prevented the increase in acute kidney injury biomarkers in cisplatin-treated patients. Therefore, it is a promising agent in reducing cisplatin-induced nephrotoxicity.Trial registration Clinical Trials.gov identifier: NCT04217512, registered in January 2020 " retrospectively registered".

Na/H Exchange Regulatory Factor 1 Deficient Mice Show Evidence of Oxidative Stress and Altered Cisplatin Pharmacokinetics

(1) Background: One third of patients who receive cisplatin develop an acute kidney injury. We previously demonstrated the Na/H Exchange Regulatory Factor 1 (NHERF1) loss resulted in increased kidney enzyme activity of the pentose phosphate pathway and was associated with more severe cisplatin nephrotoxicity. We hypothesized that changes in proximal tubule biochemical pathways associated with NHERF1 loss alters renal metabolism of cisplatin or response to cisplatin, resulting in exacerbated nephrotoxicity. (2) Methods: 2-4 month-old male wild-type and NHERF1 knock out littermate mice were treated with either vehicle or cisplatin (20 mg/kg dose IP), with samples taken at either 4, 24, or 72 h. Kidney injury was determined by urinary neutrophil gelatinase-associated lipocalin and histology. Glutathione metabolites were measured by HPLC and genes involved in glutathione synthesis were measured by qPCR. Kidney handling of cisplatin was assessed by a kidney cortex measurement of γ-glutamyl transferase activity, Western blot for γ-glutamyl transferase and cysteine S-conjugate beta lyase, and ICP-MS for platinum content. (3) Results: At 24 h knock out kidneys show evidence of greater tubular injury after cisplatin and exhibit a decreased reduced/oxidized glutathione ratio under baseline conditions in comparison to wild-type. KO kidneys fail to show an increase in γ-glutamyl transferase activity and experience a more rapid decline in tissue platinum when compared to wild-type. (4) Conclusions: Knock out kidneys show evidence of greater oxidative stress than wild-type accompanied by a greater degree of early injury in response to cisplatin. NHERF1 loss has no effect on the initial accumulation of cisplatin in the kidney cortex but is associated with an altered redox status which may alter the activity of enzymes involved in cisplatin metabolism.

Mechanisms of Cisplatin-Induced Acute Kidney Injury: Pathological Mechanisms, Pharmacological Interventions, and Genetic Mitigations

Administration of the chemotherapeutic agent cisplatin leads to acute kidney injury (AKI). Cisplatin-induced AKI (CIAKI) has a complex pathophysiological map, which has been linked to cellular uptake and efflux, apoptosis, vascular injury, oxidative and endoplasmic reticulum stress, and inflammation. Despite research efforts, pharmaceutical interventions, and clinical trials spanning over several decades, a consistent and stable pharmacological treatment option to reduce AKI in patients receiving cisplatin remains unavailable. This has been predominately linked to the incomplete understanding of CIAKI pathophysiology and molecular mechanisms involved. Herein, we detail the extensively known pathophysiology of cisplatin-induced nephrotoxicity that manifests and the variety of pharmacological and genetic alteration studies that target them.

F127/Cisplatin Microemulsions: In Vitro, In Vivo and Computational Studies

The development of effective strategies for local administration of chemotherapeutic drugs, thus minimizing the adverse side effects to patients, is one of the key challenges in biomedicine and cancer research. This work reports the formulation and characterization of PluronicF127 microemulsions to enhance the bioavailability of Cisplatin (Cis). The size of Cis microemulsion was about 12.0 nm, as assessed by dynamic light scattering analysis. In vitro cytotoxic activity of free Cis and F127/Cis microemulsions were studied on malignant (C152 and MCF7) and normal (HUVEC) cells via tetrazolium (MTT) colorimetric assay. Cell morphology was also monitored. In vitro assessments revealed thatF127/Cis microemulsions induced cytotoxicity/morphological changes to a lesser extent than free Cis. Regarding in vivo experiments, F127/Cis microemulsions were injected intraperitoneally at 7 and 14 mg/kg doses into adult male Wistar rats to assess histologic and biochemical changes. In this case, the bulk Cis group caused severe histopathological changes and significant increases in serum liver enzymes and serum kidney function markers. The group treated with the 14 mg/kg dose of F127/Cis microemulsions also showed severe fatty changes and significant increases in serum liver enzymes, blood urea nitrogen, and creatinine levels. The group treated with the low dose of nano-Cis showed a significant increase in serum liver enzymes levels accompanied by mild fatty changes of the liver. Theoretical surveys were performed to get an understanding of the interplay between F127 and Cis. Results reveal that hydrogen bonding (HB) interactions with F127have an influence on the molecular properties of Cis and may playa role in the lower toxicity of F127/Cis in comparison to free Cis.

A highly annotated database of genes associated with platinum resistance in cancer

Platinum-based chemotherapy, including cisplatin, carboplatin, and oxaliplatin, is prescribed to 10-20% of all cancer patients. Unfortunately, platinum resistance develops in a significant number of patients and is a determinant of clinical outcome. Extensive research has been conducted to understand and overcome platinum resistance, and mechanisms of resistance can be categorized into several broad biological processes, including (1) regulation of drug entry, exit, accumulation, sequestration, and detoxification, (2) enhanced repair and tolerance of platinum-induced DNA damage, (3) alterations in cell survival pathways, (4) alterations in pleiotropic processes and pathways, and (5) changes in the tumor microenvironment. As a resource to the cancer research community, we provide a comprehensive overview accompanied by a manually curated database of the >900 genes/proteins that have been associated with platinum resistance over the last 30 years of literature. The database is annotated with possible pathways through which the curated genes are related to platinum resistance, types of evidence, and hyperlinks to literature sources. The searchable, downloadable database is available online at http://ptrc-ddr.cptac-data-view.org .

Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology

Individual cells and epithelia control the chemical exchange with the surrounding environment by the fine-tuned expression, localization, and function of an array of transmembrane proteins that dictate the selective permeability of the lipid bilayer to small molecules, as actual gatekeepers to the interface with the extracellular space. Among the variety of channels, transporters, and pumps that localize to cell membrane, organic cation transporters (OCTs) are considered to be extremely relevant in the transport across the plasma membrane of the majority of the endogenous substances and drugs that are positively charged near or at physiological pH. In humans, the following six organic cation transporters have been characterized in regards to their respective substrates, all belonging to the solute carrier 22 (SLC22) family: the organic cation transporters 1, 2, and 3 (OCT1–3); the organic cation/carnitine transporter novel 1 and 2 (OCTN1 and N2); and the organic cation transporter 6 (OCT6). OCTs are highly expressed on the plasma membrane of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives). As part of the Special Issue Physiology, Biochemistry, and Pharmacology of Transporters for Organic Cations, this article critically presents the physio-pathological, pharmacological, and toxicological roles of OCTs in the tissues in which they are primarily expressed.

PPAR-α Deletion Attenuates Cisplatin Nephrotoxicity by Modulating Renal Organic Transporters MATE-1 and OCT-2

Cisplatin is a chemotherapy drug widely used in the treatment of solid tumors. However, nephrotoxicity has been reported in about one-third of patients undergoing cisplatin therapy. Proximal tubules are the main target of cisplatin toxicity and cellular uptake; elimination of this drug can modulate renal damage. Organic transporters play an important role in the transport of cisplatin into the kidney and organic cations transporter 2 (OCT-2) has been shown to be one of the most important transporters to play this role. On the other hand, multidrug and toxin extrusion 1 (MATE-1) transporter is the main protein that mediates the extrusion of cisplatin into the urine. Cisplatin nephrotoxicity has been shown to be enhanced by increased OCT-2 and/or reduced MATE-1 activity. Peroxisome proliferator-activated receptor alpha (PPAR-α) is the transcription factor which controls lipid metabolism and glucose homeostasis; it is highly expressed in the kidneys and interacts with both MATE-1 and OCT-2. Considering the above, we treated wild-type and PPAR-α knockout mice with cisplatin in order to evaluate the severity of nephrotoxicity. Cisplatin induced renal dysfunction, renal inflammation, apoptosis and tubular injury in wild-type mice, whereas PPAR-α deletion protected against these alterations. Moreover, we observed that cisplatin induced down-regulation of organic transporters MATE-1 and OCT-2 and that PPAR-α deletion restored the expression of these transporters. In addition, PPAR-α knockout mice at basal state showed increased MATE-1 expression and reduced OCT-2 levels. Here, we show for the first time that PPAR-α deletion protects against cisplatin nephrotoxicity and that this protection is via modulation of the organic transporters MATE-1 and OCT-2.

The identification of dual protective agents against cisplatin-induced oto- and nephrotoxicity using the zebrafish model

Dose-limiting toxicities for cisplatin administration, including ototoxicity and nephrotoxicity, impact the clinical utility of this effective chemotherapy agent and lead to lifelong complications, particularly in pediatric cancer survivors. Using a two-pronged drug screen employing the zebrafish lateral line as an in vivo readout for ototoxicity and kidney cell-based nephrotoxicity assay, we screened 1280 compounds and identified 22 that were both oto- and nephroprotective. Of these, dopamine and L-mimosine, a plant-based amino acid active in the dopamine pathway, were further investigated. Dopamine and L-mimosine protected the hair cells in the zebrafish otic vesicle from cisplatin-induced damage and preserved zebrafish larval glomerular filtration. Importantly, these compounds did not abrogate the cytotoxic effects of cisplatin on human cancer cells. This study provides insights into the mechanisms underlying cisplatin-induced oto- and nephrotoxicity and compelling preclinical evidence for the potential utility of dopamine and L-mimosine in the safer administration of cisplatin.

Toxic Peripheral Neuropathies: Agents and Mechanisms

Toxic peripheral neuropathies are an important form of acquired polyneuropathy produced by a variety of xenobiotics and different exposure scenarios. Delineating the mechanisms of neurotoxicants and determining the degenerative biological pathways triggered by peripheral neurotoxicants will facilitate the development of sensitive and specific biochemical-based methods for identifying neurotoxicants, designing therapeutic interventions, and developing structure-activity relationships for predicting potential neurotoxicants. This review presents an overview of the general concepts of toxic peripheral neuropathies with the goal of providing insight into why certain agents target the peripheral nervous system and produce their associated lesions. Experimental data and the main hypotheses for the mechanisms of selected agents that produce neuronopathies, axonopathies, or myelinopathies including covalent or noncovalent modifications, compromised energy or protein biosynthesis, and oxidative injury and disruption of ionic gradients across membranes are presented. The relevance of signaling between the main components of peripheral nerve, that is, glia, neuronal perikaryon, and axon, as a target for neurotoxicants and the contribution of active programmed degenerative pathways to the lesions observed in toxic peripheral neuropathies is also discussed.

The Predictive Role of the Biomarker Kidney Molecule-1 (KIM-1) in Acute Kidney Injury (AKI) Cisplatin-Induced Nephrotoxicity

Acute kidney injury (AKI) following platinum-based chemotherapeutics is a frequently reported serious side-effect. However, there are no approved biomarkers that can properly identify proximal tubular injury while routine assessments such as serum creatinine lack sensitivity. Kidney-injury-molecule 1 (KIM-1) is showing promise in identifying cisplatin-induced renal injury both in vitro and in vivo studies. In this review, we focus on describing the mechanisms of renal tubular cells cisplatin-induced apoptosis, the associated inflammatory response and oxidative stress and the role of KIM-1 as a possible biomarker used to predict cisplatin associated AKI.

Melatonin Attenuates Cisplatin-Induced Acute Kidney Injury through Dual Suppression of Apoptosis and Necroptosis

Melatonin is well known to modulate the sleep-wake cycle. Accumulating evidence suggests that melatonin also has favorable effects such as anti-oxidant and anti-inflammatory properties in numerous disease models. It has been reported that melatonin has therapeutic effects against cisplatin-induced acute kidney injury (AKI). However, mechanisms underlying the therapeutic action of melatonin on the renal side-effects of cisplatin therapy remain poorly understood. In this study, we showed that melatonin treatment significantly ameliorates cisplatin-induced acute renal failure and histopathological alterations. Increased expression of tubular injury markers was largely reduced by melatonin. Melatonin treatment inhibited caspase-3 activation and apoptotic cell death. Moreover, protein levels of key components of the molecular machinery for necroptosis were decreased by melatonin. Melatonin also attenuated nuclear factor-κB activation and suppressed expression of pro-inflammatory cytokines. Consistent with in vivo findings, melatonin dose-dependently decreased apoptosis and necroptosis in cisplatin-treated mouse renal tubular epithelial cells. Collectively, our findings suggest that melatonin ameliorates cisplatin-induced acute renal failure and structural damages through dual suppression of apoptosis and necroptosis. These results reveal a novel mechanism underlying the therapeutic effect of melatonin against cisplatin-induced AKI and strengthen the idea that melatonin might be a promising therapeutic agent for the renal side-effects of cisplatin therapy.

Advances in Toxicological Research of the Anticancer Drug Cisplatin

Cisplatin is one of the most widely used chemotherapeutic agents for various solid tumors in the clinic due to its high efficacy and broad spectrum. The antineoplastic activity of cisplatin is mainly due to its ability to cross-link with DNA, thus blocking transcription and replication. Unfortunately, the clinical use of cisplatin is limited by its severe, dose-dependent toxic side effects. There are approximately 40 specific toxicities of cisplatin, among which nephrotoxicity is the most common one. Other common side effects include ototoxicity, neurotoxicity, gastrointestinal toxicity, hematological toxicity, cardiotoxicity, and hepatotoxicity. These side effects together reduce the life quality of patients and require lowering the dosage of the drug, even stopping administration, thus weakening the treatment effect. Few effective measures exist clinically against these side effects because the exact mechanisms of various side effects from cisplatin remain still unclear. Therefore, substantial effort has been made to explore the complicated biochemical processes involved in the toxicology of cisplatin, aiming to identify effective ways to reduce or eradicate its toxicity. This review summarizes and reviews the updated advances in the toxicological research of cisplatin. We anticipate to provide insights into the understanding of the mechanisms underlying the side effects of cisplatin and designing comprehensive therapeutic strategies involving cisplatin.

Recent Advances in Models, Mechanisms, Biomarkers, and Interventions in Cisplatin-Induced Acute Kidney Injury

Cisplatin is a widely used chemotherapeutic agent used to treat solid tumours, such as ovarian, head and neck, and testicular germ cell. A known complication of cisplatin administration is acute kidney injury (AKI). The development of effective tumour interventions with reduced nephrotoxicity relies heavily on understanding the molecular pathophysiology of cisplatin-induced AKI. Rodent models have provided mechanistic insight into the pathophysiology of cisplatin-induced AKI. In the subsequent review, we provide a detailed discussion of recent advances in the cisplatin-induced AKI phenotype, principal mechanistic findings of injury and therapy, and pre-clinical use of AKI rodent models. Cisplatin-induced AKI murine models faithfully develop gross manifestations of clinical AKI such as decreased kidney function, increased expression of tubular injury biomarkers, and tubular injury evident by histology. Pathways involved in AKI include apoptosis, necrosis, inflammation, and increased oxidative stress, ultimately providing a translational platform for testing the therapeutic efficacy of potential interventions. This review provides a discussion of the foundation laid by cisplatin-induced AKI rodent models for our current understanding of AKI molecular pathophysiology.

Loss of the Na+/H+ Exchange Regulatory Factor 1 Increases Susceptibility to Cisplatin-Induced Acute Kidney Injury

Na⁺/H⁺ exchange regulatory cofactor (NHERF)-1, a scaffolding protein, anchors multiple membrane proteins in renal proximal tubules. Cultured proximal tubule cells deficient in Nherf1 and proximal tubules from Nherf1-deficient mice exhibit aberrant trafficking. Nherf1-deficient cells also exhibit an altered transcription pattern and worse survival. These observations suggest that NHERF1 loss increases susceptibility to acute kidney injury (AKI). Male and female wild-type C57BL/6J and Nherf1 knockout mice were treated with saline or cisplatin (20 mg/kg dose i.p.) to induce AKI and were euthanized after 72 hours. Blood and urine were collected for assessments of blood urea nitrogen and neutrophil gelatinase-associated lipocalin, respectively. Kidneys were harvested for histology (hematoxylin and eosin, periodic acid-Schiff) and terminal deoxynucleotidyl transferase dUTP nick end labeling assay, Kim1 mRNA assessment, and Western blot analysis for cleaved caspase 3. Cisplatin treatment was associated with significantly greater severity of AKI in knockout compared with wild-type mice, as demonstrated by semiquantitative injury score (2.8 versus 1.89, P < 0.001), blood urea nitrogen (151.8 ± 17.2 mg/dL versus 97.8 ± 10.1 mg/dL, P < 0.05), and neutrophil gelatinase-associated lipocalin urine protein (55.6 ± 21.3 μg/mL versus 2.7 ± 0.53 μg/mL, P < 0.05). Apoptosis markers were significantly increased in cisplatin-treated Nherf1 knockout and wild-type mice compared to respective controls. These data suggest that NHERF1 loss increases susceptibility to AKI.

The Protective Effects of Ciji-Hua'ai-Baosheng II Formula on Chemotherapy-Treated H22 Hepatocellular Carcinoma Mouse Model by Promoting Tumor Apoptosis

Ciji-Hua'ai-Baosheng II Formula (CHB-II-F) is a traditional Chinese medical formula that has been shown in clinical practice to relieve side effects of chemotherapy and improve quality of life for cancer patients. In order to understand the mechanism of its protective effects on chemotherapy, mice with transplanted H₂₂ hepatocellular carcinoma were employed in this study. Ninety-two mice were injected subcutaneously with H₂₂ HCC cell suspension into the right anterior armpit. After mice were treated with 5-fluorine pyrimidine (5-FU), they were divided into six groups as untreated group, 5-FU group, 5-FU plus Yangzheng Xiaoji Capsule group and three groups of 5-FU plus different concentrations of CHB-II-F. Twenty mice were euthanized after 7 days of treatment in untreated and medium concentration of CHB-II-F groups and all other mice were euthanized after 14 days of treatment. Herbal components/metabolites were analyzed by UPLC-MS. Tumors were evaluated by weight and volume, morphology of light and electron microscope, and cell cycle. Apoptosis were examined by apoptotic proteins expression by western blot. Four major components/metabolites were identified from serum of mice treated with CHB-II-F and they are β-Sitosterol, Salvianolic acid, isobavachalcone, and bakuchiol. Treatment of CHB-II-F significantly increased body weights of mice and decreased tumor volume compared to untreated group. Moreover, CHB-II-F treatment increased tumor cells in G₀-G₁ transition instead of in S phase. Furthermore, CHB-II-F treatment increased the expression of pro-apoptotic proteins and decreased the expression anti-apoptotic protein. Therefore, CHB-II-F could improve mice general condition and reduce tumor cell malignancy. Moreover, CHB-II-F regulates apoptosis of tumor cells, which could contribute its protective effect on chemotherapy.

Genetic Variations and Cisplatin Nephrotoxicity: A Systematic Review

Background: Nephrotoxicity is a notable adverse effect in cisplatin treated patients characterized by tubular injury and/or increased serum creatinine (SCr) with incidence varying from 20 to 70%. Pharmacogenomics has been shown to identify strongly predictive genetic markers to help determine which patients are more likely to experience, for example, a serious adverse drug reaction or receive optimal benefit through enhanced efficacy. Genetic variations have been reported to influence the risk of cisplatin nephrotoxicity; however, a comprehensive overview is lacking. Methods: A systematic review was performed using Pubmed, Embase and Web of Science on clinical studies that used cisplatin-based chemotherapy as treatment, had available genotyping data, and evaluated nephrotoxicity as an outcome. The quality of reporting was assessed using the STrengthening the REporting of Genetic Association Studies (STREGA) checklist. Results: Twenty-eight eligible studies were included; all were candidate gene studies. Over 300 SNPs across 135 genes were studied; 29 SNPs in 14 genes were significantly associated with cisplatin-induced nephrotoxicity. A variation in SLC22A2 rs316019, a gene involved in platinum uptake by the kidney, was associated with different measures of nephrotoxicity in four independent studies. Further, variants of ERCC1 (rs11615 and rs3212986) and ERCC2 (rs13181), two genes involved in DNA repair, were found to be positively associated with increased risks of nephrotoxicity in two independent studies. Conclusion: Three genes consistently associated with cisplatin-induced nephrotoxicity. Further research is needed to assess the biological mechanism and the clinical value of modifying treatment based on SLCC22A2 and ERCC1/2 genotypes.

Non-Platinum Metal Complexes as Potential Anti-Triple Negative Breast Cancer Agents

Breast cancer (BC) is the most common cancer in women worldwide, with a mortality rate that has been forecasted to rise in the next decade. This is especially worrying for people with triple-negative BC (TNBC), because of its unresponsiveness to current therapies. Different drugs to treat TNBC have been assessed, and, although platinum chemotherapy drugs seem to offer some hope, their drawbacks have motivated extensive investigations into alternative metal-based BC therapies. This paper aims to: (i) describe the preliminary in vitro and in vivo anticancer properties of non-platinum metal-based complexes (NPMBC) against TNBC; and (ii) analyze the likely molecular targets involved in their anticancer activity.

S100A9 regulates cisplatin chemosensitivity of squamous cervical cancer cells and related mechanism

Objective

Our previous research has shown that the expression of S100 calcium-binding protein A9 (S100A9) in tumor cells was associated with neoadjuvant chemotherapy sensitivity in cervical squamous cell carcinoma. In the present study, we altered the expression of S100A9 through infecting lentivirus, investigated its effect on the chemosensitivity to cisplatin of cervical cancer cells and then made a primary exploration of the involved mechanism.

Materials and methods

Lentivirus was employed to upregulate and downregulate S100A9 expression in SiHa cells. The protein expression level of apoptotic-related proteins Bcl-2 and Bax, drug resistance-related proteins multiple drug resistance protein 1 (MRP1), P glycoprotein (P-gp), glutathione-S-transferase-π (GST-π), lung resistance-related protein (LRP), and FOXO1 signaling pathway related proteins was detected by Western blot. The CCK-8 assay was used to examine chemosensitivity to cisplatin, and the proportion of apoptosis cells was analyzed by the flow cytometry.

Results

S100A9 overexpression could obviously increase the IC50 value of SiHa cells to cisplatin and decrease the apoptosis rate induced by cisplatin. Downregulation of S100A9 led to the opposite results. In S100A9 overexpression SiHa cells, the expression level of Bcl-2, LRP, GST-π, p-AKT, p-ERK, p-FOXO1, and Nanog was significantly increased, while FOXO1 expression was decreased. The opposite results were observed in S100A9 knockdown SiHa cells.

Conclusion

Downregulation of S100A9 could significantly increase apoptosis rate, resulting in enhancing sensitivity of SiHa cells to cisplatin, which may be related to Bcl-2, GST-π, and LRP protein and by altering the AKT/ERK-FOXO1-Nanog signaling pathway.

Theaflavin-3,3'-Digallate Enhances the Inhibitory Effect of Cisplatin by Regulating the Copper Transporter 1 and Glutathione in Human Ovarian Cancer Cells

Ovarian cancer has the highest fatality rate among the gynecologic cancers. The side effects, high relapse rate, and drug resistance lead to low long-term survival rate (less than 40%) of patients with advanced ovarian cancer. Theaflavin-3,3'-digallate (TF3), a black tea polyphenol, showed less cytotoxicity to normal ovarian cells than ovarian cancer cells. We aimed to investigate whether TF3 could potentiate the inhibitory effect of cisplatin against human ovarian cancer cell lines. In the present study, combined treatment with TF3 and cisplatin showed a synergistic cytotoxicity against A2780/CP70 and OVCAR3 cells. Treatment with TF3 could increase the intracellular accumulation of platinum (Pt) and DNA-Pt adducts and enhanced DNA damage induced by cisplatin in both cells. Treatment with TF3 decreased the glutathione (GSH) levels and upregulated the protein levels of the copper transporter 1 (CTR1) in both cells, which led to the enhanced sensitivity of both ovarian cancer cells to cisplatin. The results imply that TF3 might be used as an adjuvant to potentiate the inhibitory effect of cisplatin against advanced ovarian cancer.

On the toxicity and transport mechanisms of cisplatin in kidney tissues in comparison to a gold-based cytotoxic agent

Mechanisms of toxicity and cellular transport of anticancer metallodrugs, including platinum-based agents, have not yet been fully elucidated. Here, we studied the toxic effects and accumulation mechanisms of cisplatin in healthy rat kidneys ex vivo, using the Precision Cut Tissue Slices (PCTS) method. In addition, for the first time, we investigated the nephrotoxic effects of an experimental anticancer cyclometallated complex [Au(py^b-H)(PTA)Cl]PF₆ (PTA = 1,3,5-triazaphosphaadamantane). The viability of the kidney slices after metallodrug treatment was evaluated by ATP content determination and histomorphology analysis. A concentration dependent decrease in viability of PCKS was observed after exposure to cisplatin or the Au(iii) complex, which correlated with the increase in slice content of Pt and Au, respectively. Metal accumulation in kidney slices was analysed by ICP-MS. The involvement of OCTs and MATE transporters in the accumulation of both metal compounds in kidneys was evaluated co-incubating the tissues with cimitedine, inhibitor of OCT and MATE. Studies of mRNA expression of the markers KIM-1, villin, p53 and Bax showed that cisplatin damages proximal tubules, whereas the Au(iii) complex preferentially affects the distal tubules. However, no effect of cimetidine on the toxicity or accumulation of cisplatin and the Au(iii) complex was observed. The effect of temperature on metallodrug accumulation in kidneys suggests the involvement of a carrier-mediated uptake process, other than OCT2, for cisplatin; while carrier-mediated excretion was suggested in the cases of the Au(iii) complex.

Platinum-induced neurotoxicity: A review of possible mechanisms

Patients treated with platinum-based chemotherapy frequently experience neurotoxic symptoms, which may lead to premature discontinuation of therapy. Despite discontinuation of platinum drugs, these symptoms can persist over a long period of time. Cisplatin and oxaliplatin, among all platinum drugs, have significant neurotoxic potential. A distal dose-dependent symmetrical sensory neuropathy is the most common presentation of platinum neurotoxicity. DNA damage-induced apoptosis of dorsal root ganglion (DRG) neurons seems to be the principal cause of neurological symptoms. However, DRG injury alone cannot explain some unique symptoms such as cold-aggravated burning pain affecting distal extremities that is observed with oxaliplatin administration. In this article, we briefly reviewed potential mechanisms for the development of platinum drugs-associated neurological manifestations.

Acquired resistance of pancreatic cancer cells to cisplatin is multifactorial with cell context-dependent involvement of resistance genes

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal of malignancies, in large measure, due to the propensity of PDAC cells to acquire resistance to chemotherapeutic agents. A better understanding of the molecular basis of acquired resistance is a major focus of contemporary PDAC research. We report here the results of a study to independently develop cisplatin resistance in two distinct parental PDAC cell lines, AsPC1 and BxPC3, and to subsequently examine the molecular mechanisms associated with the acquired resistance. Cisplatin resistance in both resistant cell lines was found to be multifactorial and to be associated with mechanisms related to drug transport, drug inactivation, DNA damage response, DNA repair and the modulation of apoptosis. Our results demonstrate that the two resistant cell lines employed alternative molecular strategies in acquiring resistance dictated, in part, by pre-existing molecular differences between the parental cell lines. Collectively, our findings indicate that strategies to inhibit or reverse acquired resistance of PDAC cells to cisplatin, and perhaps other chemotherapeutic agents, may not be generalized but will require individual molecular profiling and analysis to be effective.

Molecular mechanisms of cisplatin resistance in cervical cancer

Patients with advanced or recurrent cervical cancer have poor prognosis, and their 1-year survival is only 10%–20%. Chemotherapy is considered as the standard treatment for patients with advanced or recurrent cervical cancer, and cisplatin appears to treat the disease effectively. However, resistance to cisplatin may develop, thus substantially compromising the efficacy of cisplatin to treat advanced or recurrent cervical cancer. In this article, we systematically review the recent literature and summarize the recent advances in our understanding of the molecular mechanisms underlying cisplatin resistance in cervical cancer.

Effect of Ondansetron on Metformin Pharmacokinetics and Response in Healthy Subjects

The 5-hydroxytryptamine-3 (5-HT3) receptor antagonists such as ondansetron have been used to prevent and treat nausea and vomiting for over 2 decades. This study was to determine whether ondansetron could serve as a perpetrator drug causing transporter-mediated drug-drug interactions in humans. Twelve unrelated male healthy Chinese volunteers were enrolled into a prospective, randomized, double-blind, crossover study to investigate the effects of ondansetron or placebo on the pharmacokinetics of and the response to metformin, a well-characterized substrate of organic cation transporters and multidrug and toxin extrusions (MATEs). Ondansetron treatment caused a statistically significantly higher Cmax of metformin compared with placebo (18.3 ± 5.05 versus 15.2 ± 3.23; P = 0.006) and apparently decreased the renal clearance of metformin by 37% as compared with placebo (P = 0.001). Interestingly, ondansetron treatment also statistically significantly improved glucose tolerance in subjects, as indicated by the smaller glucose area under the curve in the oral glucose tolerance test (10.4 ± 1.43) as compared with placebo (11.5 ± 2.29 mmol∙mg/l) (P = 0.020). It remains possible that ondansetron itself may affect glucose homeostasis in human subjects, but our clinical study, coupled with our previous findings in cells and in animal models, indicates that ondansetron can cause a drug-drug interaction via its potent inhibition of MATE transporters in humans.

Quantitative imaging of platinum based on laser ablation-inductively coupled plasma-mass spectrometry to investigate toxic side effects of cisplatin

This work presents a quantitative bioimaging method for platinum based on laser ablation-inductively coupled plasma-mass spectrometry and its application for a biomedical study concerning toxic side effects of cisplatin. To trace the histopathology back to cisplatin, platinum was localized and quantified in major functional units of testicle, cochlea, kidney, nerve and brain sections from cisplatin treated mice. The direct consideration of the histology enables precise interpretation of the Pt images and the novel quantitative evaluation approach allows significantly more precise investigations than the pure image. For the first time, platinum was detected and quantified in all major injured structures including organ of Corti of cochlea and seminiferous tubule of testicle. In this way, proximal tubule in kidney, Leydig cells in testicle, stria vascularis and organ of Corti in cochlea and nerve fibers in sciatic nerves are confirmed as targets of cisplatin in these organs. However, the accumulation of platinum in almost all investigated structures also raises questions about more complex pathogenesis including direct and indirect interruption of several biological processes.

Current View in Platinum Drug Mechanisms of Peripheral Neurotoxicity

Peripheral neurotoxicity is the dose-limiting factor for clinical use of platinum derivatives, a class of anticancer drugs which includes cisplatin, carboplatin, and oxaliplatin. In particular cisplatin and oxaliplatin induce a severe peripheral neurotoxicity while carboplatin is less neurotoxic. The mechanisms proposed to explain these drugs' neurotoxicity are dorsal root ganglia alteration, oxidative stress involvement, and mitochondrial dysfunction. Oxaliplatin also causes an acute and reversible neuropathy, supposed to be due by transient dysfunction of the voltage-gated sodium channels of sensory neurons. Recent studies suggest that individual genetic variation may play a role in the pathogenesis of platinum drug neurotoxicity. Even though all these mechanisms have been investigated, the pathogenesis is far from clearly defined. In this review we will summarize the current knowledge and the most up-to-date hypotheses on the mechanisms of platinum drug-induced peripheral neurotoxicity.

Nanostructures Control the Hepatocellular Responses to a Cytotoxic Agent "Cisplatin"

In drug discovery programs, the alteration between in vivo and in vitro cellular responses to drug represents one of the main challenges. Since the variation in the native extracellular matrix (ECM) between in vivo and 2D in vitro conditions is one of the key reasons for such discrepancies, thus the utilization of substrate that likely mimics ECM characteristics (topography, stiffness, and chemical composition) is needed to overcome such problem. Here, we investigated the role of substrate nanotopography as one of the major determinants of hepatic cellular responses to a chemotherapeutic agent "cisplatin." We studied the substratum induced variations in cisplatin cytotoxicity; a higher cytotoxic response to cisplatin was observed for cells cultured on the nanopattern relative to a flat substrate. Moreover, the nanofeatures with grating shapes that mimic the topography of major ECM protein constituents (collagen) induced alterations in the cellular orientation and chromatin condensation compared to flat surfaces. Accordingly, the developments of biomimetic substrates with a particular topography could have potentials in drug development analyses to reflect more physiological mimicry conditions in vitro.

Sensory hair cell death and regeneration in fishes

Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation vs. direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

Disease pathways at the Rat Genome Database Pathway Portal: genes in context-a network approach to understanding the molecular mechanisms of disease

BACKGROUND

Biological systems are exquisitely poised to respond and adjust to challenges, including damage. However, sustained damage can overcome the ability of the system to adjust and result in a disease phenotype, its underpinnings many times elusive. Unraveling the molecular mechanisms of systems biology, of how and why it falters, is essential for delineating the details of the path(s) leading to the diseased state and for designing strategies to revert its progression. An important aspect of this process is not only to define the function of a gene but to identify the context within which gene functions act. It is within the network, or pathway context, that the function of a gene fulfills its ultimate biological role. Resolving the extent to which defective function(s) affect the proceedings of pathway(s) and how altered pathways merge into overpowering the system's defense machinery are key to understanding the molecular aspects of disease and envisioning ways to counteract it. A network-centric approach to diseases is increasingly being considered in current research. It also underlies the deployment of disease pathways at the Rat Genome Database Pathway Portal. The portal is presented with an emphasis on disease and altered pathways, associated drug pathways, pathway suites, and suite networks.

RESULTS

The Pathway Portal at the Rat Genome Database (RGD) provides an ever-increasing collection of interactive pathway diagrams and associated annotations for metabolic, signaling, regulatory, and drug pathways, including disease and altered pathways. A disease pathway is viewed from the perspective of networks whose alterations are manifested in the affected phenotype. The Pathway Ontology (PW), built and maintained at RGD, facilitates the annotations of genes, the deployment of pathway diagrams, and provides an overall navigational tool. Pathways that revolve around a common concept and are globally connected are presented within pathway suites; a suite network combines two or more pathway suites.

CONCLUSIONS

The Pathway Portal is a rich resource that offers a range of pathway data and visualization, including disease pathways and related pathway suites. Viewing a disease pathway from the perspective of underlying altered pathways is an aid for dissecting the molecular mechanisms of disease.

Cellular transport mechanisms of cytotoxic metallodrugs: an overview beyond cisplatin

The field of medicinal inorganic chemistry has grown consistently during the past 50 years; however, metal-containing coordination compounds represent only a minor proportion of drugs currently on the market, indicating that research in this area has not yet been thoroughly realized. Although platinum-based drugs as cancer chemotherapeutic agents have been widely studied, exact knowledge of the mechanisms governing their accumulation in cells is still lacking. However, evidence suggests active uptake and efflux mechanisms are involved; this may be involved also in other experimental metal coordination and organometallic compounds with promising antitumor activities in vitro and in vivo, such as ruthenium and gold compounds. Such knowledge would be necessary to elucidate the balance between activity and toxicity profiles of metal compounds. In this review, we present an overview of the information available on the cellular accumulation of Pt compounds from in vitro, in vivo and clinical studies, as well as a summary of reports on the possible accumulation mechanisms for different families of experimental anticancer metal complexes (e.g., Ru Au and Ir). Finally, we discuss the need for rationalization of the investigational approaches available to study metallodrug cellular transport.