Cisplatin based therapy: the role of the mitogen activated protein kinase signaling pathway

Functional Analysis of BARD1 Missense Variants on Homology-Directed Repair in Ovarian and Breast Cancers

Women with germline BRCA1 mutations face an increased risk of developing breast and ovarian cancers. BARD1 (BRCA1 associated RING domain 1) is an essential heterodimeric partner of BRCA1, and mutations in BARD1 are also associated with these cancers. While BARD1 mutations are recognized for their cancer susceptibility, the exact roles of numerous BARD1 missense mutations remain unclear. In this study, we conducted functional assays to assess the homology-directed DNA repair (HDR) activity of all BARD1 missense substitutions identified in 55 breast and ovarian cancer samples, using the real-world data from the COSMIC and cBioPortal databases. Seven BARD1 variants (V85M, P187A, G491R, R565C, P669L, T719R, and Q730L) were confirmed to impair DNA damage repair. Furthermore, cells harboring these BARD1 variants exhibited increased sensitivity to the chemotherapeutic drugs, cisplatin, and olaparib, compared to cells expressing wild-type BARD1. These findings collectively suggest that these seven missense BARD1 variants are likely pathogenic and may respond well to cisplatin-olaparib combination therapy. This study not only enhances our understanding of BARD1's role in DNA damage repair but also offers valuable insights into predicting therapy responses in patients with specific BARD1 missense mutations.

Synergic effects of DL-limonene, R-limonene, and cisplatin on AKT, PI3K, and mTOR gene expression in MDA-MB-231 and 5637 cell lines

The anticancer and cytotoxic effects of DL-Limonene and R-Limonene are well-documented. However, the role of natural compounds in enhancing the efficacy of platinum-based drugs like Cisplatin (CisPt) remains debated. This study aims to boost Cisplatin's impact on breast (MDA-MB-231) and bladder (5637) cancer cells using DL-Limonene and R-Limonene. Different concentrations of DL-Limonene, R-Limonene, and Cisplatin, combined, were used to treat MDA-MB-231 and 5637 cells in this experimental study. The cell's viability was evaluated using an MTT assay. AnnexinV- PI staining was applied to evaluate the percentage of apoptotic cells. Cytotoxicity results showed that combining DL-Limonene, R-Limonene, and Cisplatin significantly improved outcomes in MDA-MB-231 cells (P < 0.05). Annexin/PI staining revealed apoptosis rates of 74 %, 28 %, 43 %, 81 %, and 91 % for Cisplatin40, R-Limonen1000, DL-Limonen1000, R-Limonen1000/DL-Limonen1000, and the combined treatment, respectively, versus 13 % in the control. The combination also resulted in the greatest reduction of AKT, PI3K, and mTOR gene expression. Our results show that R-Limonene and DL-Limonene enhance Cisplatin's cancer-inhibiting effects in breast and bladder cancer cell lines. These compounds may be promising for combination therapy, potentially allowing for lower doses of chemotherapy and reducing side effects like nephrotoxicity.

Hearing loss during chemotherapy: prevalence, mechanisms, and protection

Ototoxicity is an often-underestimated sequela for cancer patients undergoing chemotherapy, with an incidence rate exceeding 50%, affecting approximately 4 million individuals worldwide each year. Despite the nearly 2,000 publications on chemotherapy-related ototoxicity in the past decade, the understanding of its prevalence, mechanisms, and preventative or therapeutic measures remains ambiguous and subject to debate. To date, only one drug, sodium thiosulfate, has gained FDA approval for treating ototoxicity in chemotherapy. However, its utilization is restricted. This review aims to offer clinicians and researchers a comprehensive perspective by thoroughly and carefully reviewing available data and current evidence. Chemotherapy-induced ototoxicity is characterized by four primary symptoms: hearing loss, tinnitus, vertigo, and dizziness, originating from both auditory and vestibular systems. Hearing loss is the predominant symptom. Amongst over 700 chemotherapeutic agents documented in various databases, only seven are reported to induce hearing loss. While the molecular mechanisms of the hearing loss caused by the two platinum-based drugs are extensively explored, the pathways behind the action of the other five drugs are primarily speculative, rooted in their therapeutic properties and side effects. Cisplatin attracts the majority of attention among these drugs, encompassing around two-thirds of the literature regarding ototoxicity in chemotherapy. Cisplatin ototoxicity chiefly manifests through the loss of outer hair cells, possibly resulting from damages directly by cisplatin uptake or secondary effects on the stria vascularis. Both direct and indirect influences contribute to cisplatin ototoxicity, while it is still debated which path is dominant or where the primary target of cisplatin is located. Candidates for hearing protection against cisplatin ototoxicity are also discussed, with novel strategies and methods showing promise on the horizon.

What is the Reason That the Pharmacological Future of Chemotherapeutics in the Treatment of Lung Cancer Could Be Most Closely Related to Nanostructures? Platinum Drugs in Therapy of Non-Small and Small Cell Lung Cancer and Their Unexpected, Possible Interactions. The Review

Over the course of several decades, anticancer treatment with chemotherapy drugs for lung cancer has not changed significantly. Unfortunately, this treatment prolongs the patient's life only by a few months, causing many side effects in the human body. It has also been proven that drugs such as Cisplatin, Carboplatin, Oxaliplatin and others can react with other substances containing an aromatic ring in which the nitrogen atom has a free electron group in its structure. Thus, such structures may have a competitive effect on the nucleobases of DNA. Therefore, scientists are looking not only for new drugs, but also for new alternative ways of delivering the drug to the cancer site. Nanotechnology seems to be a great hope in this matter. Creating a new nanomedicine would reduce the dose of the drug to an absolute minimum, and thus limit the toxic effect of the drug; it would allow for the exclusion of interactions with competitive compounds with a structure similar to nucleobases; it would also permit using the so-called targeted treatment and bypassing healthy cells; it would allow for the introduction of other treatment options, such as radiotherapy directly to the cancer site; and it would provide diagnostic possibilities. This article is a review that aims to systematize the knowledge regarding the anticancer treatment of lung cancer, but not only. It shows the clear possibility of interactions of chemotherapeutics with compounds competitive to the nitrogenous bases of DNA. It also shows the possibilities of using nanostructures as potential Platinum drug carriers, and proves that nanomedicine can easily become a new medicinal product in personalized medicine.

Advances in Microfluidic-Based Core@Shell Nanoparticles Fabrication for Cancer Applications

Current research in cancer therapy focuses on personalized therapies, through nanotechnology-based targeted drug delivery systems. Particularly, controlled drug release with nanoparticles (NPs) can be designed to safely transport various active agents, optimizing delivery to specific organs and tumors, minimizing side effects. The use of microfluidics (MFs) in this field has stood out against conventional methods by allowing precise control over parameters like size, structure, composition, and mechanical/biological properties of nanoscale carriers. This review compiles applications of microfluidics in the production of core-shell NPs (CSNPs) for cancer therapy, discussing the versatility inherent in various microchannel and/or micromixer setups and showcasing how these setups can be utilized individually or in combination, as well as how this technology allows the development of new advances in more efficient and controlled fabrication of core-shell nanoformulations. Recent biological studies have achieved an effective, safe, and controlled delivery of otherwise unreliable encapsulants such as small interfering RNA (siRNA), plasmid DNA (pDNA), and cisplatin as a result of precisely tuned fabrication of nanocarriers, showing that this technology is paving the way for innovative strategies in cancer therapy nanofabrication, characterized by continuous production and high reproducibility. Finally, this review analyzes the technical, biological, and technological limitations that currently prevent this technology from becoming the standard.

Natural products reverse cisplatin resistance in the hypoxic tumor microenvironment

Cisplatin is one of the most commonly used drugs for cancer treatment. Despite much progress in improving patient outcomes, many patients are resistant to cisplatin-based treatments, leading to limited treatment efficacy and increased treatment failure. The fact that solid tumors suffer from hypoxia and an inadequate blood supply in the tumor microenvironment has been widely accepted for decades. Numerous studies have shown that a hypoxic microenvironment significantly reduces the sensitivity of tumor cells to cisplatin. Therefore, understanding how hypoxia empowers tumor cells with cisplatin resistance is essential. In the fight against tumors, developing innovative strategies for overcoming drug resistance has attracted widespread interest. Natural products have historically made major contributions to anticancer drug research due to their obvious efficacy and abundant candidate resources. Intriguingly, natural products show the potential to reverse chemoresistance, which provides new insights into cisplatin resistance in the hypoxic tumor microenvironment. In this review, we describe the role of cisplatin in tumor therapy and the mechanisms by which tumor cells generate cisplatin resistance. Subsequently, we call attention to the linkage between the hypoxic microenvironment and cisplatin resistance. Furthermore, we summarize known and potential natural products that target the hypoxic tumor microenvironment to overcome cisplatin resistance. Finally, we discuss the current challenges that limit the clinical application of natural products. Understanding the link between hypoxia and cisplatin resistance is the key to unlocking the full potential of natural products, which will serve as new therapeutic strategies capable of overcoming resistance.

Effects of artemisinin and cisplatin on the malignant progression of oral leukoplakia. In vitro and in vivo study

OBJECTIVES

Chemoprevention can be a treatment for potentially malignant lesions (PMLs). We aimed to evaluate whether artemisinin (ART) and cisplatin (CSP) are associated with apoptosis and immunogenic cell death (ICD) in vitro, using oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) cell lines, and whether these compounds prevent OL progression in vivo.

METHODS

Normal keratinocytes (HaCat), Dysplastic oral cells (DOK), and oral squamous cell carcinoma (SCC-180) cell lines were treated with ART, CSP, and ART + CSP to analyze cytotoxicity, genotoxicity, cell migration, and increased expression of proteins related to apoptosis and ICD. Additionally, 41 mice were induced with OL using 4NQO, treated with ART and CSP, and their tongues were histologically analyzed.

RESULTS

In vitro, CSP and CSP + ART showed dose-dependent cytotoxicity and reduced SCC-180 migration. No treatment was genotoxic, and none induced expression of proteins related to apoptosis and ICD; CSP considerably reduced High-mobility group box-1 (HMGB-1) protein expression in SCC-180. In vivo, there was a delay in OL progression with ART and CSP treatment; however, by the 16th week, only CSP prevented progression to OSCC.

CONCLUSION

Expression of proteins related to ICD and apoptosis did not increase with treatments, and CSP was shown to reduce immunogenic pathways in SCC-180, while reducing cell migration. ART did not prevent the malignant progression of OL in vivo; CSP did despite significant adverse effects.

SET8 inhibition preserves PTEN to attenuate kidney cell apoptosis in cisplatin nephrotoxicity

The aberrant expression of SET8, a histone methyltransferase that mediates H4 lysine 20 mono-methylation (H4K20me1), is implicated in the pathogenesis of various tumors, however, its role in acute kidney injury (AKI) is unknown. Here we showed that SET8 and H4K20me1 were upregulated in the murine kidney with AKI induced by cisplatin, along with increased renal tubular cell injury and apoptosis and decreased expression of E-cadherin and Phosphatase and Tensin Homolog (PTEN). Suppression of SET8 by UNC0379 improved renal function, attenuated tubule damage, and restored expression of PTEN, but not E-cadherin. UNC0379 was also effective in lessening cisplatin-induced DNA damage response (DDR) as indicated by reduced expression of γ-H2AX, p53, p21, and alleviating cisplatin-impaired autophagy as shown by retained expression of Atg5, Beclin-1, and CHMP2A and enhanced levels of LC3-II in the kidney. Consistently, inhibition of SET8 with either UNC0379 or siRNA mitigated apoptosis and DDR, and restored autophagy, along with PTEN preservation in cultured renal proximal tubular epithelial cell (TKPTs) exposed to cisplatin. Further studies showed that inhibition of PTEN with Bpv or siRNA potentiated cisplatin-induced apoptosis, DDR, and hindered autophagy, and conversely, alleviated by overexpression of PTEN in TKPTs. Finally, blocking PTEN largely abolished the inhibitory effect of UNC0379 on apoptosis. Taken together, these results suggest that SET8 inhibition protects against cisplatin-induced AKI and renal cell apoptosis through a mechanism associated with the preservation of PTEN, which in turn inhibits DDR and restores autophagy.

Mitochondria-Targeted Multifunctional Nanoprodrugs by Inhibiting Metabolic Reprogramming for Combating Cisplatin-Resistant Lung Cancer

How to address the resistance of cisplatin (CDDP) has always been a clinical challenge. The resistance mechanism of platinum-based drugs is very complex, including nuclear DNA damage repair, apoptosis escape, and tumor metabolism reprogramming. Tumor cells can switch between mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis and develop resistance to chemotherapy drugs through metabolic variability. In addition, due to the lack of histone protection and a relatively weak damage repair ability, mitochondrial DNA (mtDNA) is more susceptible to damage, which in turn affects mitochondrial OXPHOS and can become a potential target for platinum-based drugs. Therefore, mitochondria, as targets of anticancer drugs, have become a hot topic in tumor resistance research. This study constructed a self-assembled nanotargeted drug delivery system LND-SS-Pt-TPP/HA-CD. β-Cyclodextrin-grafted hydronic acid (HA-CD)-encapsulated prodrug nanoparticles can target CD44 on the tumor surface and further deliver the prodrug to intracellular mitochondria through a triphenylphosphine group (TPP+). Disulfide bonds can be selectively degraded by glutathione (GSH) in mitochondria, releasing lonidamine (LND) and the cisplatin prodrug (Pt(IV)). Under the action of GSH and ascorbic acid, Pt(IV) is further reduced to cisplatin (Pt(II)). Cisplatin can cause mtDNA damage, induce mitochondrial dysfunction and mitophagy, and then affect mitochondrial OXPHOS. Meanwhile, LND can reduce the hexokinase II (HK II) level, induce destruction of mitochondria, and block energy supply by glycolysis inhibition. Ultimately, this self-assembled nano targeted delivery system can synergistically kill cisplatin-resistant lung cancer cells, which supplies an overcome cisplatin resistance choice via the disrupt mitochondria therapy.

The Role and Efficacy of JNK Inhibition in Inducing Lung Cancer Cell Death Depend on the Concentration of Cisplatin

Toxicity and the emergence of resistance are the main challenges in cancer treatment. The optimal dose of cisplatin, one of the most widely used chemotherapeutic anticancer drugs, is currently being widely debated. Furthermore, the dose-dependent molecular mechanisms of its action are poorly understood. To assess the role of protein kinase JNK (cJun N-terminal kinase) signaling in lung cancer treatment, we combined small-molecule JNK inhibitors and cisplatin. Wild-type p53 (tumor suppressor transcription factor TP53) and mutated RAS-bearing lung adenocarcinoma cell line A549 was used as a model in our studies. Here, we demonstrate cisplatin concentration-dependent opposing roles of JNK in killing cancer cells: a cell-protective role at low cisplatin concentrations and an apoptosis-promoting (or neutral) role at high concentrations. Time- and dose-dependent activation of pro-survival protein kinase AKT and TP53 was shown, with similar activation dynamics in cells exposed to different (low and high) cisplatin concentrations. Selective inhibition of AKT and activation of TP53 (expression and phosphorylation) led to a decrease in cell survival, indicating their involvement in cisplatin-induced cell death regulation. The activation levels of TP53 and AKT in cisplatin-treated A549 cells after cotreatment with the JNK inhibitor SP600125 correlated with their role in regulating cell death. TP53 and AKT were proposed as signaling proteins mediating the outcome of JNK inhibition in A549 cells exposed to different concentrations of cisplatin. Our findings suggest that a combination of stress kinase JNK inhibition and low-dose cisplatin, together with manipulation of drug-induced signaling, could be considered as a promising treatment strategy for certain lung cancers.

The role of oxidative stress in intervertebral disc degeneration: Mechanisms and therapeutic implications

Oxidative stress is one of the main driving mechanisms of intervertebral disc degeneration(IDD). Oxidative stress has been associated with inflammation in the intervertebral disc, cellular senescence, autophagy, and epigenetics of intervertebral disc cells. It and the above pathological mechanisms are closely linked through the common hub reactive oxygen species(ROS), and promote each other in the process of disc degeneration and promote the development of the disease. This reveals the important role of oxidative stress in the process of IDD, and the importance and great potential of IDD therapy targeting oxidative stress. The efficacy of traditional therapy is unstable or cannot be maintained. In recent years, due to the rise of materials science, many bioactive functional materials have been applied in the treatment of IDD, and through the combination with traditional drugs, satisfactory efficacy has been achieved. At present, the research review of antioxidant bioactive materials in the treatment of IDD is not complete. Based on the existing studies, the mechanism of oxidative stress in IDD and the common antioxidant therapy were summarized in this paper, and the strategies based on emerging bioactive materials were reviewed.

Ondansetron attenuates cisplatin-induced behavioral and cognitive impairment through downregulation of NOD-like receptor inflammasome pathway

Cisplatin is an effective and commonly used chemotherapeutic drug; however, its use is accompanied by several adverse effects, including chemobrain. Ondansetron is a 5-HT3 antagonist, commonly used in prophylactic against chemotherapy-induced nausea and vomiting. Moreover, it has been identified as a novel neuroprotective agent in different animal models. However, its protective role against chemotherapy-induced chemobrain has not been investigated. The current study was the first study that explored the potential neuroprotective effect of ondansetron against cisplatin-induced chemobrain in rats. Cisplatin (5 mg/Kg) was injected intraperitoneally, once weekly, for 4 weeks with the daily administration of ondansetron (0.5 and 1 mg/Kg). Compared to the cisplatin-treated group, ondansetron administration showed a significant decrease in the latency time and a significant increase in ambulation, rearing, and grooming frequency in the open field test (OFT). Moreover, a significant improvement in the latency time in the rotarod and passive avoidance tests, following ondansetron administration. In addition, ondansetron treatment increased the percentage of alternation in the Y-maze test. Also, ondansetron showed a remarkable enhancement in the biochemical parameters in the hippocampus. It increased the acetylcholine (Ach) level and decreased the level of the acetylcholine esterase enzyme (AchE). Ondansetron significantly decreased interleukin-1β (Il-1β), tumor necrosis factor-alpha (TNF-α), toll-like receptor-4 (TLR-4), NOD-like receptor-3 (NLRP3) inflammasome as well as caspase-1 and caspase-3 levels. Furthermore, ondansetron significantly decreased the levels of copper transporter-1(CTR1) expression in the hippocampus. Collectively, these findings suggest that ondansetron may exhibit a neuroprotective and therapeutic activity against cisplatin-induced chemobrain.

USP28 promotes tumorigenesis and cisplatin resistance by deubiquitinating MAST1 protein in cancer cells

Cisplatin is a chemotherapy drug that causes a plethora of DNA lesions and inhibits DNA transcription and replication, resulting in the induction of apoptosis in cancer cells. However, over time, patients develop resistance to cisplatin due to repeated treatment and thus the treatment efficacy is limited. Therefore, identifying an alternative therapeutic strategy combining cisplatin treatment along with targeting factors that drive cisplatin resistance is needed. CRISPR/Cas9 system-based genome-wide screening for the deubiquitinating enzyme (DUB) subfamily identified USP28 as a potential DUB that governs cisplatin resistance. USP28 regulates the protein level of microtubule-associated serine/threonine kinase 1 (MAST1), a common kinase whose expression is elevated in several cisplatin-resistant cancer cells. The expression level and protein turnover of MAST1 is a major factor driving cisplatin resistance in many cancer types. Here we report that the USP28 interacts and extends the half-life of MAST1 protein by its deubiquitinating activity. The expression pattern of USP28 and MAST1 showed a positive correlation across a panel of tested cancer cell lines and human clinical tissues. Additionally, CRISPR/Cas9-mediated gene knockout of USP28 in A549 and NCI-H1299 cells blocked MAST1-driven cisplatin resistance, resulting in suppressed cell proliferation, colony formation ability, migration and invasion in vitro. Finally, loss of USP28 destabilized MAST1 protein and attenuated tumor growth by sensitizing cells to cisplatin treatment in mouse xenograft model. We envision that targeting the USP28-MAST1 axis along with cisplatin treatment might be an alternative therapeutic strategy to overcome cisplatin resistance in cancer patients.

Cancer Mutations Converge on a Collection of Protein Assemblies to Predict Resistance to Replication Stress

Rapid proliferation is a hallmark of cancer associated with sensitivity to therapeutics that cause DNA replication stress (RS). Many tumors exhibit drug resistance, however, via molecular pathways that are incompletely understood. Here, we develop an ensemble of predictive models that elucidate how cancer mutations impact the response to common RS-inducing (RSi) agents. The models implement recent advances in deep learning to facilitate multidrug prediction and mechanistic interpretation. Initial studies in tumor cells identify 41 molecular assemblies that integrate alterations in hundreds of genes for accurate drug response prediction. These cover roles in transcription, repair, cell-cycle checkpoints, and growth signaling, of which 30 are shown by loss-of-function genetic screens to regulate drug sensitivity or replication restart. The model translates to cisplatin-treated cervical cancer patients, highlighting an RTK-JAK-STAT assembly governing resistance. This study defines a compendium of mechanisms by which mutations affect therapeutic responses, with implications for precision medicine.

SIGNIFICANCE

Zhao and colleagues use recent advances in machine learning to study the effects of tumor mutations on the response to common therapeutics that cause RS. The resulting predictive models integrate numerous genetic alterations distributed across a constellation of molecular assemblies, facilitating a quantitative and interpretable assessment of drug response. This article is featured in Selected Articles from This Issue, p. 384.

p90RSK pathway inhibition synergizes with cisplatin in TMEM16A overexpressing head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) constitutes one of the most common types of human cancers and often metastasizes to lymph nodes. Platinum-based chemotherapeutic drugs are commonly used for treatment of a wide range of cancers, including HNSCC. Its mode of action relies on its ability to impede DNA repair mechanisms, inducing apoptosis in cancer cells. However, due to acquired resistance and toxic side-effects, researchers have been focusing on developing novel combinational therapeutic strategies to overcome cisplatin resistance. In the current study, we identified p90RSK, an ERK1/2 downstream target, as a key mediator and a targetable signaling node against cisplatin resistance. Our results strongly support the role of p90RSK in cisplatin resistance and identify the combination of p90RSK inhibitor, BI-D1870, with cisplatin as a novel therapeutic strategy to overcome cisplatin resistance. In addition, we have identified TMEM16A expression as a potential upstream regulator of p90RSK through the ERK pathway and a biomarker of response to p90RSK targeted therapy in the context of cisplatin resistance.

Esketamine induces apoptosis of nasopharyngeal carcinoma cells through the PERK/CHOP pathway

Nasopharyngeal carcinoma, a malignant tumor prevalent in southeast Asia and north Africa, still lacks effective treatment. Esketamine, an N-methyl-D-aspartatic acid (NMDA) receptor (NMDAR) antagonist, is widely used in clinical anesthesia. Emerging evidence suggests that esketamine plays an important role in inhibiting tumor cell activity. However, the underlying mechanisms of esketamine on nasopharyngeal carcinoma remain unknown. In this study, we found that esketamine inhibited the proliferation and migration of nasopharyngeal carcinoma cells. Mechanically, transcriptome sequencing and subsequent verification experiments revealed that esketamine promoted the apoptosis of nasopharyngeal carcinoma cells through endoplasmic reticulum stress PERK/ATF4/CHOP signaling pathway mediated by NMDAR. Additionally, when combined with esketamine, the inhibitory effect of cisplatin on the proliferation of nasopharyngeal carcinoma cells was significantly enhanced. These findings provide new insights into future anti-nasopharyngeal carcinoma clinical strategies via targeting the NMDAR/PERK/CHOP axis alone or in combination with cisplatin.

Scanning ion conductance microscopy revealed cisplatin-induced morphological changes related to apoptosis in single adenocarcinoma cells

The studies of drug-induced apoptosis play a vital role in the identification of potential drugs that could treat diseases such as cancer. Alterations in the native morphology of cancer cells following treatment with anticancer drugs serve as one of the indicators that reveal drug efficacy. Various techniques such as optical microscopy, electron microscopy (EM), and atomic force microscopy (AFM) have been used to map the three dimensional (3D) morphological changes in cells induced with drugs. However, caution should be exercised when interpreting morphological data from techniques that might alter the native morphology of cells, caused by phototoxicity, electron beam invasiveness, intrusive sample preparation, and cell membrane deformation. Herein, we have used scanning ion conductance microscopy (SICM) to study the 3D morphology and roughness of A549 adenocarcinoma cells under physiological conditions before and after cisplatin induced apoptosis, where we observed an increase in height, overall shrinkage of the cells, and irregular features form on the cell membrane. Tracking the morphology of the same single A549 cells exposed to cisplatin unveiled heterogeneity in response to the drug, formation of membrane blebs, and an increase in membrane roughness. We have also demonstrated the use of SICM for studying the effect of cisplatin on the dynamic changes in the volume of A549 cells over days. SICM is demonstrated as a technique for studying the effect of drug induced apoptosis in the same cells over time, and for multiple different single cells.

Mechanisms underlying dose-limiting toxicities of conventional chemotherapeutic agents

Dose-limiting toxicities (DLTs) are severe adverse effects that define the maximum tolerated dose of a cancer drug. In addition to the specific mechanisms of each drug, common contributing factors include inflammation, apoptosis, ion imbalances, and tissue-specific enzyme deficiencies. Among various DLTs are bleomycin-induced pulmonary fibrosis, doxorubicin-induced cardiomyopathy, cisplatin-induced nephrotoxicity, methotrexate-induced hepatotoxicity, vincristine-induced neurotoxicity, paclitaxel-induced peripheral neuropathy, and irinotecan, which elicits severe diarrhea. Currently, specific treatments beyond dose reduction are lacking for most toxicities. Further research on cellular and molecular pathways is imperative to improve their management. This review synthesizes preclinical and clinical data on the pharmacological mechanisms underlying DLTs and explores possible treatment approaches. A comprehensive perspective reveals knowledge gaps and emphasizes the need for future studies to develop more targeted strategies for mitigating these dose-dependent adverse effects. This could allow the safer administration of fully efficacious doses to maximize patient survival.

The regulatory relationship between transcription factor STAT3 and noncoding RNA

Signal transducer and activator of transcription 3 (STAT3), as a key node in numerous carcinogenic signaling pathways, is activated in various tumor tissues and plays important roles in tumor formation, metastasis, and drug resistance. STAT3 is considered a potential subtarget for tumor therapy. Noncoding RNA (ncRNA) is a special type of RNA transcript. Transforming from "junk" transcripts into key molecules involved in cell apoptosis, growth, and functional regulation, ncRNA has been proven to be closely related to various epithelial-mesenchymal transition and drug resistance processes in tumor cells over the past few decades. Research on the relationship between transcription factor STAT3 and ncRNAs has attracted increased attention. To date, existing reviews have mainly focused on the regulation by ncRNAs on the transcription factor STAT3; there has been no review of the regulation by STAT3 on ncRNAs. However, understanding the regulation of ncRNAs by STAT3 and its mechanism is important to comprehensively understand the mutual regulatory relationship between STAT3 and ncRNAs. Therefore, in this review, we summarize the regulation by transcription factor STAT3 on long noncoding RNA, microRNA, and circular RNA and its possible mechanisms. In addition, we provide an update on research progress on the regulation of STAT3 by ncRNAs. This will provide a new perspective to comprehensively understand the regulatory relationship between transcription factor STAT3 and ncRNAs, as well as targeting STAT3 or ncRNAs to treat diseases such as tumors.

Inhibitors Targeting the F-BOX Proteins

F-box proteins are involved in multiple cellular processes through ubiquitylation and consequent degradation of targeted substrates. Any significant mutation in F-box protein-mediated proteolysis can cause human malformations. The various cellular processes F-box proteins involved include cell proliferation, apoptosis, invasion, angiogenesis, and metastasis. To target F-box proteins and their associated signaling pathways for cancer treatment, researchers have developed thousands of F-box inhibitors. The most advanced inhibitor of FBW7, NVD-BK M120, is a powerful P13 kinase inhibitor that has been proven to bring about apoptosis in cancerous human lung cells by disrupting levels of the protein known as MCL1. Moreover, F-box Inhibitors have demonstrated their efficacy for treating certain cancers through targeting particular mutated proteins. This paper explores the key studies on how F-box proteins act and their contribution to malignancy development, which fabricates an in-depth perception of inhibitors targeting the F-box proteins and their signaling pathways that eventually isolate the most promising approach to anti-cancer treatments.

Lysophosphatidic acid exerts protective effects on HEI-OC1 cells against cytotoxicity of cisplatin by decreasing apoptosis, excessive autophagy, and accumulation of ROS

Lysophosphatidic acid (LPA) is an active phospholipid signaling molecule that binds to six specific G protein-coupled receptors (LPA1-6) on the cell surface and exerts a variety of biological functions, including cell migration and proliferation, morphological changes, and anti-apoptosis. The earliest study from our group demonstrated that LPA treatment could restore cochlear F-actin depolymerization induced by noise exposure, reduce hair cell death, and thus protect hearing. However, whether LPA could protect against cisplatin-induced ototoxicity and which receptors play the major role remain unclear. To this end, we integrated the HEI-OC1 mouse cochlear hair cell line and zebrafish model, and found that cisplatin exposure induced a large amount of reactive oxygen species accumulation in HEI-OC1 cells, accompanied by mitochondrial damage, leading to apoptosis and autophagy. LPA treatment significantly attenuated autophagy and apoptosis in HEI-OC1 cells after cisplatin exposure. Further investigation revealed that all LPA receptors except LPA3 were expressed in HEI-OC1 cells, and the mRNA expression level of LPA1 receptor was significantly higher than that of other receptors. When LPA1 receptor was silenced, the protective effect of LPA was reduced and the proportion of apoptosis cells was increased, indicating that LPA-LPA1 plays an important role in protecting HEI-OC1 cells from cisplatin-induced apoptosis. In addition, the behavioral trajectory and in vivo fluorescence imaging results showed that cisplatin exposure caused zebrafish to move more actively, and the movement speed and distance were higher than those of the control and LPA groups, while LPA treatment reduced the movement behavior. Cisplatin caused hair cell death and loss in zebrafish lateral line, and LPA treatment significantly protected against hair cell death and loss. LPA has a protective effect on hair cells in vitro and in vivo against the cytotoxicity of cisplatin, and its mechanism may be related to reducing apoptosis, excessive autophagy and ROS accumulation.

Evaluation of the therapeutic efficacy of Vitex agnus-castus extract on cisplatin-induced hematotoxicity in female Wistar rats

Background and Aim

Cisplatin (CP) is a preferred drug for cancer treatment but it has dose-dependent side effects. Vitex agnus-castus (VAC) berry extract has antioxidant, free-radical scavenging, and anti-inflammatory activities. This study explored the mitigating effects of VAC extract (VACE) on acute hematotoxicity induced by CP in female Wistar rats.

Materials and Methods

Female Wistar rats (n = 30) were randomly divided into five groups (n = 6/group). The normal control (NC) group received no treatment. The CP control group received CP (7 mg/kg.b.w. ip, single dose) and the drug control group (VACE-650) received VACE (650 mg/kg b.w. oral, daily) for 7 days. Both groups received a single dose of CP (7 mg/kg b.w. ip), followed by 350 and 650 mg/kg.b.w. of VACE daily orally (CPVACE-350 and CPVACE-650 groups, respectively) for 7 days.

Results

After a single dose of CP (7 mg/kg b.w.), the red blood cells (RBC), hematocrit (HCT), white blood cells (WBC), and platelets significantly decreased. In the VAC-350 group, the reduction in total WBC count was less than that in the VAC-650 group on the 3rd day. The RBC and HCT values of the VACE groups were better than that of the CP control, but the VACE-350 treatment group showed significant improvement only on the 3rd day.

Conclusion

Our findings showed that VACE can mitigate CP-induced damage to peripheral blood cells at lower doses.

3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) protects hair cells from cisplatin-induced ototoxicity in vitro: possible relation to the activities of p38 MAPK signaling pathway

The 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) gene encodes rate-limiting enzyme in cholesterol biosynthesis, which is related to cell proliferation and mitochondrial function. The present study was designed to explore the expression of HMGCR in murine cochlear hair cells and HEI-OC1 cells and the possible mechanisms underpinning the actions of HMGCR in cisplatin-induced ototoxicity, with special attention given to p38 mitogen-activated protein kinase (MAPK) activities in vitro. The expressions of HMGCR, p-p38, cleaved caspase-3 and LC3B was measured by immunofluorescence and western blot. JC-1 staining and MitoSOX Red were used to detect mitochondria membrane potential (MMP) and reactive oxygen species (ROS) levels respectively. The apoptosis of auditory cells was assessed by TUNEL staining and flow cytometry. Protein levels of bcl2/bax and beclin1 were examined by western blot. We found that HMGCR was widely expressed in the auditory cells, of both neonatal mice and 2-month-old mice, in cytoplasm, nucleus and stereocilia. Moreover, 30 μM cisplatin elicited the formation of ROS, which, in turn, led to HMGCR reduction, activating p38 kinase-related apoptosis and autophagy in auditory cells. Meanwhile, co-treatment with ROS scavenger at a concentration of 2 mM, N-acetyl-L-cysteine (NAC), could alleviate the aforementioned changes. In addition, HMGCR silencing resulted in higher p38 MAPK-mediated apoptosis and autophagy under cisplatin injury. Taken together, we demonstrate that, for the first time, that HMGCR is expressed in the cochlear. Furthermore, HMGCR exerts protective benefit on auditory cells against cisplatin-mediated injury stimulated by ROS, culminating in regulation of p38 MAPK-dependent apoptosis and autophagy.

CAB39 promotes cisplatin resistance in bladder cancer via the LKB1-AMPK-LC3 pathway

Systemic therapy for muscle-invasive bladder cancer (BC) remains dominated by cisplatin-based chemotherapy. However, resistance to cisplatin therapy greatly limits long-term survival. Resistance to cisplatin-based chemotherapy still needs to be addressed. In this study, we established three cisplatin-resistant BC cell lines by multiple cisplatin pulse treatments. Interestingly, after exposure to cisplatin, all cisplatin-resistant cell lines showed lower reactive oxygen species (ROS) levels than the corresponding parental cell lines. Using proteomic analysis, we identified 35 proteins that were upregulated in cisplatin-resistant BC cells. By knocking down eleven of these genes, we found that after CAB39 knockdown, BC cisplatin-resistant cells were more sensitive to cisplatin. Overexpression of CAB39 had the opposite effect. Then, the knockdown of six genes downstream of CAB39 revealed that CAB39 promoted cisplatin resistance in BC through LKB1. Moreover, a key cause of cisplatin-induced cell death is damage to mitochondria and increased ROS levels. In our study, cisplatin-resistant cells exhibited higher autophagic flux and healthier mitochondrial status after cisplatin exposure. We demonstrated that the CAB39-LKB1-AMPK-LC3 pathway plays a critical role in enhancing autophagy to maintain the health of mitochondria and reduce ROS levels. In addition, the autophagy inhibitor chloroquine (CQ) can significantly enhance the killing effect of cisplatin on BC cells. Compared with gemcitabine plus cisplatin (GC), GC plus CQ significantly reduced tumor burden in vivo. In conclusion, our study shows that CAB39 counteracts the killing of cisplatin by enhancing the autophagy of BC cells to damaged mitochondria and other organelles to alleviate the damage of cells caused by harmful substances such as ROS.

Kuwanon H Inhibits Melanoma Growth through Cytotoxic Endoplasmic Reticulum Stress and Impaired Autophagy Flux

Although great progress has been made recently in targeted and immune-based therapies, additional treatments are needed for most melanoma patients due to acquired chemoresistance, recurrence, or metastasis. Elevated autophagy is required for the pathogenesis of melanoma to attenuate metabolic stress, protecting cancer cells from chemotherapeutics or radiation. Thus, intervention with autophagy is a promising strategy for melanoma treatment. Here, we examined a novel antimelanoma natural compound named kuwanon H (KuH), which significantly inhibited melanoma cell growth in vitro/vivo. Mechanistically, KuH induced cytotoxic endoplasmic reticulum (ER) stress, which inhibited cell viability and induced apoptosis. Meanwhile, KuH-induced ER stress mediated autophagysome formation through the ATF4-DDIT3-TRIB3-AKT-MTOR axis. Importantly, KuH impaired autophagy flux, which contributed to the anticancer effects of KuH. Finally, our results showed that KuH enhanced the sensitivity of melanoma cells to cisplatin, both in vitro and in vivo, by impairing autophagy degradation of reactive oxygen species and damaged mitochondria. Our findings indicate that KuH is a promising candidate anticancer natural product for melanoma therapy.

GABBR2 as a Downstream Effector of the Androgen Receptor Induces Cisplatin Resistance in Bladder Cancer

The precise molecular mechanisms responsible for resistance to cisplatin-based chemotherapy in patients with bladder cancer remain elusive, while we have indicated that androgen receptor (AR) activity in urothelial cancer is associated with its sensitivity. Our DNA microarray analysis in control vs. AR-knockdown bladder cancer sublines suggested that the expression of a GABA B receptor GABBR2 and AR was correlated. The present study aimed to determine the functional role of GABBR2 in modulating cisplatin sensitivity in bladder cancer. AR knockdown and dihydrotestosterone treatment considerably reduced and induced, respectively, GABBR2 expression, and the effect of dihydrotestosterone was at least partially restored by an antiandrogen hydroxyflutamide. A chromatin immunoprecipitation assay further revealed the binding of AR to the promoter region of GABBR2 in bladder cancer cells. Meanwhile, GABBR2 expression was significantly elevated in a cisplatin-resistant bladder cancer subline, compared with control cells. In AR-positive bladder cancer cells, knockdown of GABBR2 or treatment with a selective GABA B receptor antagonist, CGP46381, considerably enhanced the cytotoxic activity of cisplatin. However, no additional effect of CGP46381 on cisplatin-induced growth suppression was seen in GABBR2-knockdown cells. Moreover, in the absence of cisplatin, CGP46381 treatment and GABBR2 knockdown showed no significant changes in cell proliferation or migration. These findings suggest that GABBR2 represents a key downstream effector of AR signaling in inducing resistance to cisplatin treatment. Accordingly, inhibition of GABBR2 has the potential of being a means of chemosensitization, especially in patients with AR/GABBR2-positive bladder cancer.

Veratricplatin inhibits the progression of hypopharyngeal squamous cell carcinoma FaDu cells in vitro and in vivo

PURPOSE

Head and neck squamous cell carcinoma (HNSCC) ranks as the sixth most prevalent cancer. In recent years, the modification of platinum(II) into platinum(IV) derivative compounds, by introducing biologically active molecules, has been extensively employed to develop novel platinum-based prodrugs. We investigated the anti-proliferative activity against HNSCC of a new veratric acid (COX-2 inhibitor)-platinum(IV) complex.

METHODS

In this study, a new veratric acid (COX-2 inhibitor)-platinum(IV) complex, termed veratricplatin, was synthesized. We evaluated the anti-tumor effect of in vitro and in vivo by western blotting, flow cytometry and DNA damage analysis.

RESULTS

Veratricplatin displayed remarkable anti-proliferative activity against various cancer cell lines, including A549, FaDu, HeLa, and MCF-7. Furthermore, veratricplatin demonstrated significantly stronger cytotoxicity than either platinum(II) or veratric acid monotherapy or their combination. Importantly, the synthesized prodrug exhibited less toxicity toward normal cells (MRC-5), while dramatically enhanced DNA damage in FaDu cells inducing apoptosis. Moreover, veratricplatin markedly reduced the migration ability of FaDu cells compared to the control or monotherapy. In vivo, veratricplatin displayed potent anti-tumor activity with no apparent toxicity in BALB/c nude mice bearing FaDu tumors. In addition, tissue immunofluorescence analysis revealed that veratricplatin could substantially inhibit the formation of tumor blood vessels.

CONCLUSION

Veratricplatin demonstrated remarkable drug efficacy, in terms of increased cytotoxicity in vitro and high efficiency with low toxicity in vivo.

MicroRNA-144-3p protects against chemotherapy-induced apoptosis of ovarian granulosa cells and activation of primordial follicles by targeting MAP3K9

Premature ovarian failure (POF) is defined by amenorrhea, ovarian atrophy, hypoestrogenism, elevated gonadotropin level, and infertility under the age of 40. POF is frequently induced by chemotherapeutic agents. However, the underlying mechanisms regarding chemotherapy-mediated damage to ovarian function are unclear. In this study, enhanced apoptosis of granulosa cells (GCs) and aberrant activation of primordial follicles were observed in a POF mouse model induced by cisplatin. We subsequently observed significant downregulation of miR-144-3p and upregulation of mitogen-activated protein kinase kinase kinase 9 (MAP3K9) in primary ovarian GCs from POF mice, as revealed by microarrays. Furthermore, MAP3K9 expression was higher in human ovarian granulosa cells (COV434) treated with cisplatin and was identified as a novel target of miR-144-3p. Functional analysis revealed that miR-144-3p attenuated cisplatin induced apoptosis of GCs via silencing MAP3K9 expression, which suppressed the activity of the downstream p38 mitogen activated protein kinase (MAPK) pathway. Meanwhile, miR-144-3p prevented premature primordial follicle depletion in cisplatin-induced POF mice through targeting Map3k9, which led to a decline in the phosphorylation and activation of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase b (AKT) pathway. Taken together, this study revealed the protective effects of miR-144-3p on ovarian function and shed light on the epigenetic regulatory mechanism in the development of POF, which might provide new biomarkers for the ovarian reserve.

Isoalantolactone Suppresses Glycolysis and Resensitizes Cisplatin-Based Chemotherapy in Cisplatin-Resistant Ovarian Cancer Cells

Cisplatin is a potent chemotherapeutic drug for ovarian cancer (OC) treatment. However, its efficacy is significantly limited due to the development of cisplatin resistance. Although the acquisition of cisplatin resistance is a complex process involving various molecular alterations within cancer cells, the increased reliance of cisplatin-resistant cells on glycolysis has gained increasing attention. Isoalantolactone, a sesquiterpene lactone isolated from Inula helenium L., possesses various pharmacological properties, including anticancer activity. In this study, isoalantolactone was investigated as a potential glycolysis inhibitor to overcome cisplatin resistance in OC. Isoalantolactone effectively targeted key glycolytic enzymes (e.g., lactate dehydrogenase A, phosphofructokinase liver type, and hexokinase 2), reducing glucose consumption and lactate production in cisplatin-resistant OC cells (specifically A2780 and SNU-8). Importantly, it also sensitized these cells to cisplatin-induced apoptosis. Isoalantolactone-cisplatin treatment regulated mitogen-activated protein kinase and AKT pathways more effectively in cisplatin-resistant cells than individual treatments. In vivo studies using cisplatin-sensitive and resistant OC xenograft models revealed that isoalantolactone, either alone or in combination with cisplatin, significantly suppressed tumor growth in cisplatin-resistant tumors. These findings highlight the potential of isoalantolactone as a novel glycolysis inhibitor for treating cisplatin-resistant OC. By targeting the dysregulated glycolytic pathway, isoalantolactone offers a promising approach to overcoming drug resistance and enhancing the efficacy of cisplatin-based therapies.

Elevated HMGB1 promotes the malignant progression and contributes to cisplatin resistance of non-small cell lung cancer

BACKGROUND

HMGB1 (high mobility group box B-1) exhibits crucial role in tumor genesis and development, including lung cancer. Whereas, more HMGB1-related details in non-small cell lung cancer (NSCLC) are still largely unclear.

METHODS

The HMGB1 and inflammatory factors in malignant (MPE) and non-malignant pleural effusion (BPE) were determined by ELISA. Additionally, qRT-PCR, western blot, or immunohistochemistry were used to determine HMGB1, drug-resistant and apoptotic proteins' expressions in NSCLC A549, A549-DDP cell lines, and xenograft model. Cell viability, migration/ invasion, and apoptosis were analyzed using MTT, Transwell, and flow cytometry assays, respectively.

RESULTS

Inflammatory factors and HMGB1 expressions in MPE were significantly higher than BPE of NSCLC. Compared with preoperative and adjacent tissues, significantly higher HMGB1, drug-resistant protein, and anti-apoptotic protein expressions were observed in recurrent tissues. Overexpressed HMGB1 induced NSCLC cells to exhibit stronger aggressive, proliferative, and drug-resistant features. The related abilities were reversed when HMGB1 was interfered. Overexpressed HMGB1 showed a similar co-localization with drug resistant protein P-gp in cytoplasm in xenograft model, while low HMGB1 expression localized in cell nucleus.

CONCLUSIONS

HMGB1 overexpression significantly promoted the malignant progression and cisplatin resistance of NSCLC in vitro and in vivo.

Cisplatin in Liver Cancer Therapy

Hepatocellular carcinoma (HCC) is the most common primary liver tumor and is often diagnosed at an unresectable advanced stage. Systemic chemotherapy as well as transarterial chemoembolization (TACE) and hepatic arterial infusion chemotherapy (HAIC) are used to treat advanced HCC. TACE and HAIC have long been the standard of care for patients with unresectable HCC but are limited to the treatment of intrahepatic lesions. Systemic chemotherapy with doxorubicin or chemohormonal therapy with tamoxifen have also been considered, but neither has demonstrated survival benefits. In the treatment of unresectable advanced HCC, cisplatin is administered transhepatic arterially for local treatment. Subsequently, for cisplatin-refractory cases due to drug resistance, a shift to systemic therapy with a different mechanism of action is expected to produce new antitumor effects. Cisplatin is also used for the treatment of liver tumors other than HCC. This review summarizes the action and resistance mechanism of cisplatin and describes the treatment of the major hepatobiliary cancers for which cisplatin is used as an anticancer agent, with a focus on HCC.

Monofunctional dimetallic Ru(η6-arene) complexes inhibit NOTCH1 signaling pathway and synergistically enhance anticancer effect in combination with cisplatin or vitamin C

ONS donor ligands L1-L4 were utilized in the preparation of monofunctional dimetallic Ru(η6-arene) complexes (C1-C4). These ONS donor ligand based novel tricoordinated Ru(II) complexes bearing η6-arene co-ligand were prepared for the first time. The current methodology resulted in excellent isolated yields and these complexes were characterized in detail by different spectroscopic and spectrometric techniques. The structures of C1-C2 and C4 were characterized in solid state by single crystal X-ray analysis. The in vitro anticancer analyses showed these novel complexes suppressed the growth of breast (MCF-7), liver (HepG2) and lung (A549) cancer cells. C2 suppressed the growth of these cells in dose-dependent manner revealed form the MTT and crystal violet cell viability assays. Moreover, C2 was observed the most potent complex that was used further in detailed mechanistic analyses in cancer cells. C2 showed good cytotoxic activity at 10 μM dose level as compared to cisplatin or oxaliplatin in these cancer cells. We observed morphological changes in cancer cells upon treatment with C2. Moreover, C2 suppressed the invasion and migration ability of cancer cells. C2 induced cellular senescence to retard cell growth and suppressed the formation of cancer stem cells. Importantly, C2 showed synergistic anticancer effect in combination with cisplatin and Vitamin C to further inhibit cell growth which suggested the potential role of C2 in cancer therapy. Mechanistically, C2 inhibited NOTCH1 dependent signaling pathway to suppress cancer cell invasion, migration and cancer stem cells formation. Thus, these data suggested potential role of C2 in cancer therapy by targeting NOTCH1-dependent signaling to suppress tumorigenesis. The results obtained in this study for these novel monofunctional dimetallic Ru(η6-arene) complexes showed their high anticancer potency and this study will pave to further cytotoxicity exploration on this class of complexes.

Synergistic Effect of Anethole and Platinum Drug Cisplatin against Oral Cancer Cell Growth and Migration by Inhibiting MAPKase, Beta-Catenin, and NF-κB Pathways

Cisplatin is a common drug used to treat patients with oral squamous cell carcinoma. However, cisplatin-induced chemoresistance poses a major challenge to its clinical application. Our recent study has shown that anethole possesses an anti-oral cancer effect. In this study, we examined the combined effect of anethole and cisplatin on oral cancer therapy. Gingival cancer cells Ca9-22 were cultured in the presence of various concentrations of cisplatin with or without anethole. The cell viability/proliferation and cytotoxicity were evaluated, respectively, by MTT, Hoechst staining, and LDH assay, while colony formation was measured by crystal violet. Oral cancer cell migration was evaluated by the scratch method. Apoptosis, caspase activity, oxidative stress, MitoSOX, and mitochondrial membrane potential (ΔΨm) levels were evaluated by flow cytometry, and the inhibition of signaling pathways was investigated by Western blot. Our results show that anethole (3 µM) potentiates cisplatin-induced inhibition of cell proliferation and decreases the ΔΨm on Ca9-22 cells. Furthermore, drug combination was found to inhibit cell migration and enhanced cisplatin cytotoxicity. The combination of anethole and cisplatin potentiates cisplatin-induced oral cancer cell apoptosis through the activation of caspase, while we also found anethole and cisplatin to enhance the cisplatin-induced generation of reactive oxygen species (ROS) and mitochondrial stress. In addition, major cancer signaling pathways were inhibited by the combination of anethole and cisplatin such as MAPKase, beta-catenin, and NF-κB pathways. This study reports that the combination of anethole and cisplatin might provide a beneficial effect in enhancing the cisplatin cancer cell-killing effect, thus lowering the associated side effects.

Hazard and health risk assessment of exposure to pharmaceutical active compounds via toxicological evaluation by zebrafish

The uncontrolled or continuous release of effluents from wastewater treatment plants leads to the omnipresence of pharmaceutical active compounds (PhACs) in the aquatic media. Today, this is a confirmed problem becoming a main subject of twin public and scientific concerns. However, still little information is available about the long-term impacts of these PhACs on aquatic organisms. In this review, efforts were made to reveal correlation between the occurrence in the environment, ecotoxicological and health risks of different PhACs via toxicological evaluation by zebrafish (Danio rerio). This animal model served as a bioindicator for any health impacts after the exposure to these contaminants and to better understand the responses in relation to human diseases. This review paper focused on the calculation of Risk Quotients (RQs) of 34 PhACs based on environmental and ecotoxicological data available in the literature and prediction from the ECOSAR V2.2 software. To the best of the authors' knowledge, this is the first report on the risk assessment of PhACs by the two different methods as mentioned above. RQs showed greater difference in potential environmental risks of the PhACs. These differences in risk values underline the importance of environmental and experimental factors in exposure conditions and the interpretation of RQ values. While the results showed high risk to Danio rerio of the majority of PhACs, risk qualification of the others varied between moderate to insignifiant. Further research is needed to assess pharmaceutical hazards when present in wastewater before discharge and monitor the effectiveness of treatment processes. The recent new advances in the morphological assessment of toxicant-exposed zebrafish larvae for the determination of test compounds effects on the developmental endpoints were also discussed. This review emphasizes the need for strict regulations on the release of PhACs into environmental media in order to minimize their toxicity to aquatic organisms.

Older but Stronger: Development of Platinum-Based Antitumor Agents and Research Advances in Tumor Immunity

Platinum (Pt) drugs have developed rapidly in clinical applications because of their broad and highly effective antitumor effects. In recent years, with the rapid development of immunotherapy, Pt-based antitumor agents have gained new challenges and opportunities. Since the discovery of their pharmacological effects in immunotherapy and tumor microenvironment regulation, research into Pt drugs has progressed to multi-ligand and multi-functional Pt precursors and their own shortcomings have been further highlighted. With the development of antitumor immunotherapy and the rise of combination therapy, the development of Pt-based drugs has started to move in the direction of multi-targeting, nanocarrier modification, immunotherapy and photodynamic therapy. In this paper, we first overview the recent applications of Pt-based drugs in antitumor inorganic chemistry, with a focus on summarizing the application of Pt-based drugs and their precursors in the anticancer immune response. The paper also provides a reasonable outlook on the future development of Pt-based drugs from the chemical and immunological perspectives, relying on the existing content and problems of Pt-based drug development. On the basis of the gathered information, joint multidisciplinary programs on implementing comprehensive immune analyses for the future development of novel anticancer metal compounds should be initiated.

Platin-C containing nanoparticles: a recipe for the delivery of curcumin-cisplatin combination chemotherapeutics to mitochondria

The success story of cisplatin spans over six decades now and yet it continues to be the key player in most chemotherapeutic regimens. Numerous efforts have been made to improve its efficacy, address its shortcomings, and overcome drug resistance. One such strategy is to develop new platinum(IV)-based prodrugs with functionally active ligands to deliver combination therapeutics. This strategy not only enables the drug candidate to access multiple drug targets but also enhances the kinetic inertness of platinum complexes and thereby ensures greater accumulation of active drugs at the target site. We report the synthesis of Platin-C, a platinum(IV)-based cisplatin prodrug tethered to the active component of ancient herbal medicine, curcumin, as one of the axial ligands. This combination complex showed improved chemotherapeutic efficacy in cisplatin resistant A2780/CP70 cell lines compared with the individual components. An amine-terminated biodegradable polymer was suitably functionalized with the triphenylphosphonium (TPP) cation to obtain a mitochondria-directed drug delivery platform. Quantification of Platin-C loading into these NPs using complementary techniques employing curcumin optical properties in high-performance liquid chromatography and platinum-based inductively coupled plasma mass spectrometry evidenced efficacious payload incorporation resulting in functional activities of both the components. Stability studies for a period of one week indicated that the NPs remain stable, enabling substantial loading and controlled release of the prodrug. The targeting nanoparticle (NP) platform was utilized to deliver Platin-C primarily in the mitochondrial network of cancer cells as monitored using confocal microscopy employing the green fluorescence of the curcumin pendant. Our studies showed that amine terminated NPs were relatively less efficient in their ability to target mitochondria despite being positively charged. This re-validated the importance of lipophilic positively charged TPP surface functionalities to successfully target cellular mitochondria. We validated the capabilities of Platin-C and its mitochondria-targeting nanoparticles towards inflicting mitochondria-directed activity in cisplatin-sensitive and cisplatin-resistant cell lines. Furthermore, our studies also demonstrated the effectiveness of Platin-C incorporated targeting NPs in attenuating cellular inflammatory markers by utilizing the curcumin component. This study advances our understanding of the cisplatin prodrug approach to combine chemotherapeutic and inflammatory effects in accessing combinatory pathways.

Endogenous production of ω-3 polyunsaturated fatty acids mitigates cisplatin-induced myelosuppression by regulating NRF2-MDM2-p53 signaling pathway

Cisplatin is a chemotherapy medication used to treat a wide range of cancers. A common side effect of cisplatin is myelosuppression. Research suggests that oxidative damages are strongly and consistently related to myelosuppression during cisplatin treatment. ω-3 polyunsaturated fatty acids (PUFAs) can enhance the antioxidant capacity of cells. Herein, we investigated the protective benefit of endogenous ω-3 PUFAs on cisplatin-induced myelosuppression and the underlying signaling pathways using a transgenic mfat-1 mouse model. The expression of mfat-1 gene can increase endogenous levels of ω-3 PUFAs by enzymatically converting ω-6 PUFAs. Cisplatin treatment reduced peripheral blood cells and bone marrow nucleated cells, induced DNA damage, increased the production of reactive oxygen species, and activated p53-mediated apoptosis in bone marrow (BM) cells of wild-type mice. In the transgenics, the elevated tissue ω-3 PUFAs rendered a robust preventative effect on these cisplatin-induced damages. Importantly, we identified that the activation of NRF2 by ω-3 PUFAs could trigger an antioxidant response and inhibit p53-mediated apoptosis by increasing the expression of MDM2 in BM cells. Thus, endogenous ω-3 PUFAs enrichment can strongly prevent cisplatin-induced myelosuppression by inhibiting oxidative damage and regulating the NRF2-MDM2-p53 signaling pathway. Elevation of tissue ω-3 PUFAs may represent a promising treatment strategy to prevent the side effects of cisplatin.

BDP1 as a biomarker in serous ovarian cancer

BACKGROUND

TFIIIB, an RNA polymerase III specific transcription factor has been found to be deregulated in human cancers with much of the research focused on the TBP, BRF1, and BRF2 subunits. To date, the TFIIIB specific subunit BDP1 has not been investigated in ovarian cancer but has previously been shown to be deregulated in neuroblastoma, breast cancer, and Non-Hodgkins lymphoma.

RESULTS

Using in silico analysis of clinically derived platforms, we report a decreased BDP1 expression as a result of deletion in serous ovarian cancer and a correlation with higher and advanced ovarian stages. Further analysis in the context of TP53 mutations, a major contributor to ovarian tumorigenesis, suggests that high BDP1 expression is unfavorable for overall survival and high BDP1 expression occurs in stages 2, 3 and 4 serous ovarian cancer. Additionally, high BDP1 expression is disadvantageous and unfavorable for progression-free survival. Lastly, BDP1 expression significantly decreased in patients treated with first-line chemotherapy, platin and taxane, at twelve-month relapse-free survival.

CONCLUSIONS

Taken together with a ROC analysis, the data suggest BDP1 could be of clinical relevance as a predictive biomarker in serous ovarian cancer. Lastly, this study further demonstrates that both the over- and under expression of BDP1 warrants further investigation and suggests BDP1 may exhibit dual function in the context of tumorigenesis.

Insight into autophagy in platinum resistance of cancer

Platinum drugs, as a class of widely used chemotherapy agents, frequently appear in the treatment of cancer at different phrases. However, platinum resistance is the major bottleneck of platinum drugs for exerting anti-tumor effect. At present, the mechanism of platinum resistance has been thoroughly explored in terms of drug delivery methods, DNA damage repair function, etc., but it has not yet been translated into an effective weapon for reversing platinum resistance. Recently, autophagy has been proved to be closely related to platinum resistance, and the involved molecular mechanism may provide a new perspective on platinum resistance. The aim of this review is to sort out the studies related to autophagy and platinum resistance, and to focus on summarizing the relevant molecular mechanisms, so as to provide clues for future studies related to autophagy and platinum resistance.

Conjugated Linoleic Acid strengthens the apoptotic effect of low-dose cisplatin in A549 cells by inducing Bcl-2 downregulation

One of the chemotherapeutic agents widely used in the treatment of non-small cell lung cancer (NSCLC) is cisplatin. However, the resistance of cancer cells to cisplatin and additionally serious side effects from cisplatin limit its use. Conjugated linoleic acid (CLA) has been shown to suppress the development of carcinogenesis in vitro and in vivo studies and has antitumoral activity in many cancers. The study aimed to investigate the potential effect of using cisplatin, the first-line treatment for NSCLC, in combination with CLA to increase its efficacy in low-dose use. MTT cytotoxicity assay was performed to determine the effects of CLA in combination with cisplatin on cell viability of NSCLC cell lines. The apoptotic effect of this combination on NSCLC cell lines and cell cycle distribution was determined by flow cytometry. At the same time, apoptosis and cell cycle-related gene expression levels were determined by Real-Time PCR. Combination treatment of low-dose cisplatin with CLA resulted in a significant decrease in cell viability compared to cisplatin alone, and an increase in the rate of apoptotic cells was observed. While cisplatin caused G1 phase arrest in cancer cells, there was an increase in cell percentages in S and G2 phases after combined application with CLA. In high-dose cisplatin administration, it was observed that the efficiency of the decrease in anti-apoptotic BCL2 expression related to resistance to chemotherapeutic agents was less than that of low-dose cisplatin administration. Combined administration of high-dose cisplatin with CLA significantly recovered BCL2 downregulation.

ERK inhibitor: A candidate enhancing therapeutic effects of conventional chemo-radiotherapy in esophageal squamous cell carcinoma

For patients with esophageal squamous cell carcinoma (ESCC), standard therapeutic methods (cisplatin and radiotherapy) have been found to be ineffective and severely toxic. Targeted therapy emerges as a promising solution for this dilemma. It has been reported that targeted therapies are applied alone or in combination with standard conventional therapies for the treatment of a variety of cancers. To the best of our knowledge, in patients with ESCC, the combinational methods containing standard therapy and ERK-targeted therapy have yet to be explored. To analyze the prognostic role of p-ERK in ESCC patients, the Kaplan-Meier analysis and Cox regression model were used. To assess the effects of ERK-targeted therapy (GDC0994) on ESCC cells, in vitro studies including CCK-8 assay, colony formation assay, and scratch wound healing assay were conducted. In addition, the changes in cell cycle distribution and apoptosis were analyzed by flow cytometry. Besides, to assess the efficacy of different therapies in vivo, the xenograft tumor models were established by subcutaneously inoculating tumor cells into the flank/leg of mice. In patients with ESCC, a strong correlation between the high expression level of p-ERK and the poor prognosis (p < 0.01, Log-Rank test) has been identified. By analyzing the results from CCK-8 and scratch wound healing assays, we demonstrated that the ERK inhibitor repressed the viability and migration of ESCC cells. In addition, following the treatment of GDC0994, the volumes of xenograft tumors significantly decreased (p < 0.001, one-way ANOVA). Furthermore, blocking the mitogen-activated protein kinase (MAPK/ERK) pathway enhanced the therapeutic efficacy of both cisplatin and radiotherapy (p < 0.05). These findings imply the role of p-ERK in the prognosis of ESCC patients and the therapeutic value of ERK inhibitors in ESCC.

Venlafaxine, an anti-depressant drug, induces apoptosis in MV3 human melanoma cells through JNK1/2-Nur77 signaling pathway

Introduction: Venlafaxine is one of the most commonly used anti-depressant and antineoplastic drug. Previous studies have predicted venlafaxine as an anti-cancer compound, but the therapeutic effects of venlafaxine in melanoma have not yet been demonstrated. Nur77 is an orphan nuclear receptor that highly expressed in melanoma cells and can interact with Bcl-2 to convert Bcl-2 from an antiapoptotic to a pro-apoptotic protein. Method: We examined the effects of venlafaxine in MV3 cells in vitro and MV3 xenograft tumor in nude mice. Western-blot, PCR, TUNEL assay and immunofluorescence were used to reveal the growth of melanoma cells. Results: Here, our data revealed that venlafaxine could reduce the growth, and induce apoptosis of melanoma cells through a Nur77-dependent way. Our results also showed that treatment with venlafaxine (20 mg/kg, i.p.) potently inhibited the growth of melanoma cells in nude mice. Mechanistically, venlafaxine activated JNK1/2 signaling, induced Nur77 expressions and mitochondrial localization, thereby promoting apoptosis of melanoma cells. Knockdown of Nur77 and JNK1/2, or inhibition of JNK1/2 signaling with its inhibitor SP600125 attenuated the anti-cancer effects of venlafaxine. Conclusion: In summary, our results suggested venlafaxine as a potential therapy for melanoma.

Investigation of the Apoptosis Inducing and β-catenin Silencing by Tetradentate Schiff Base Zinc(II) Complex on the T-47D Breast Cancer Cells

INTRODUCTION

Several mechanisms are known for the anticancer effects of cisplatin. However, its most wellknown function involves binding to DNA and activating the DNA damage response.

METHODS

Despite its good effects, the treatment process often leads to chemoresistance and affects the mechanisms that support cell survival, such as pathways that promote cell growth, apoptosis, DNA damage repair, and endocytosis. For this reason, we investigated the effects of a new metal complex (tetradentate Schiff base zinc(II) complex) on breast cancer cells (T-47D). We evaluated its effect on cytotoxicity, apoptosis, and drug resistance in comparison to cisplatin.

RESULTS

The results of the MTT test showed that tetradentate Schiff base zinc(II) complex has good cytotoxicity compared to cisplatin. The IC50 values for the [Zn(SB)]Cl2 complex and cisplatin after 72 h of exposure were equal to 42.1 and 276.1 μM, respectively. Real-time PCR assay confirmed that the [Zn(SB)]Cl2 complex activated the mitochondrial pathway of apoptosis and increased the expression of Bak1 and caspase-3 genes significantly compared to cisplatin. More importantly, the [Zn(SB)]Cl2 was able to reduce the expression of the β-catenin gene, which plays a role in drug resistance, by 0.011 compared to the control.

CONCLUSION

Therefore, we can hope for this new complex because, without the help of any β-catenin silencing agent, it was able to inhibit the drug resistance in the T-47D cell line that overexpresses the β-catenin gene.

Transcriptional upregulation of MAPK15 by NF-κB signaling boosts the efficacy of combination therapy with cisplatin and TNF-α

The efficacy of cisplatin in treating advanced non-small cell lung cancer is limited mainly because of insensitivity and/or acquired resistance. MAPK15, previously shown by us to enhance the sensitivity of the anti-cancer drug arsenic trioxide, could also enhance the sensitivity of other anti-cancer drugs. Here, we explore the potential role of MAPK15 in chemosensitivity to cisplatin in human lung cancer cells. Our results indicated that the expression level of MAPK15 was positively correlated with cisplatin sensitivity through affecting the DNA repair capacity of cisplatin-treated cells. The expression of MAPK15 was transcriptionally regulated by the TNF-α-activated NF-κB signaling pathway, and TNF-α synergized with cisplatin, in a MAPK15-dependent manner, to exert cytotoxicity in vitro and in vivo. Therefore, levels of TNF-α dictate the responsiveness/sensitivity of lung cancer cells to cisplatin by transcriptionally upregulating MAPK15 to enhance chemosensitivity, suggesting manipulation of MAPK15 as a strategy to improve the therapeutic efficacy of chemotherapeutic drugs.

Cisplatin-Induced Nausea and Vomiting: Effect of Herbal Medicines

Cisplatin is a chemotherapeutic agent that is widely used to treat various types of cancers. However, its side effects, most commonly nausea and vomiting, limit its widespread use. Although various drugs, such as ondansetron and aprepitant, are used to alleviate these side effects, their efficacy is still debated. This review aims to summarize the results of 14 studies on the effects of seven single herbal extracts, one multiple herbal extract, and one ginger sub-component (i.e., [6]-gingerol) on cisplatin-induced nausea and vomiting. The results of the included studies were subdivided into four categories: kaolin consumption, retching and vomiting, food intake, and weight loss. Most studies used rodents, whereas four studies used minks or pigeons. The doses of cisplatin used in the studies varied from 3 mg/kg to 7.5 mg/kg, and only a single injection was used. Nine studies analyzed the mechanisms of action of herbal medicines and assessed the involvement of neurotransmitters, cytokines, enzymes, and various hematological parameters. Although further research is needed, this review suggests herbal medicine as a viable treatment option for cisplatin-induced neuropathic pain.

Genome Mining and Metabolic Profiling Reveal Cytotoxic Cyclodipeptides in Streptomyces hygrospinosus var. Beijingensis

Two new cyclodipeptide (CDP) derivatives (1-2) and another seven known cyclodipeptides (3-9) were isolated from Streptomyces 26D9-414 by the genome mining approach combined with genetic dereplication and the "one strain many compounds" (OSMAC) strategy. The structures of the new CDPs were established on the basis of 1D- and 2D-NMR and comparative electronic circular dichroism (ECD) spectra analysis. The biosynthetic gene clusters (BGCs) for these CDPs were identified through antiSMASH analysis. The relevance between this cdp cluster and the identified nine CDPs was established by genetic interruption manipulation. The newly discovered natural compound 2 displayed comparable cytotoxicity against MDA-MB-231 and SW480 with that of cisplatin, a widely used chemotherapeutic agent for the treatment of various cancers.

Diclofenac Sensitizes Signet Ring Cell Gastric Carcinoma Cells to Cisplatin by Activating Autophagy and Inhibition of Survival Signal Pathways

Gastric cancer has one of the highest incidence rates of cancer worldwide while also contributing to increased drug resistance among patients in clinical practice. Herein, we have investigated the role of diclofenac (DCF) on sensitizing cisplatin resistance in signet ring cell gastric carcinoma cells (SRCGC). Non-toxic concentrations of DCF significantly augmented cisplatin-induced cell death in cisplatin-resistant SRCGC cells (KATO/DDP) but not in cisplatin-sensitive SRCGC cells (KATOIII). Consistently, concomitant treatment of DCF and cisplatin significantly enhanced autophagic cell death due to overproduction of intracellular reactive oxygen species (ROS). At the molecular level, the induction of ROS has been associated with a reduction in antioxidant enzymes expression while inhibiting nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Moreover, the combination of DCF and cisplatin also inhibited the expression of survival proteins including Bcl-2, Bcl-xL, cIAP1 and cyclin D1 in KATO/DDP cells when compared with cisplatin alone. This was due, at least in part, to reduce MAPKs, Akt, NF-κB, AP-1 and STAT-3 activation. Taken together, our results suggested that DCF potentiated the anticancer effect of cisplatin in SRCGC via the regeneration of intracellular ROS, which in turn promoted cell death as an autophagy mechanism and potentially modulated the cell survival signal transduction pathway.

Combined treatment of marizomib and cisplatin modulates cervical cancer growth and invasion and enhances antitumor potential in vitro and in vivo

Proteasome inhibition is an attractive approach for anticancer therapy. Cisplatin (cis-diamminedichloroplatinum, CDDP) is widely used as a standard chemotherapy drug in the treatment of solid malignant tumors, such as cervical cancer, ovarian cancer, colorectal cancer, and lung cancer. However, the development of CDDP resistance largely limits its clinical application. Proteasome inhibitors may enhance traditional chemotherapy agent-induced cytotoxicity and apoptosis. Marizomib (NPI-0052, salinosporamide A, Mzb), a second-generation proteasome inhibitor, shows synergistic anticancer activity with some drugs. Currently, the effect of Mzb on cervical cancer cell proliferation remains unclear. In this study, we explored the role of Mzb in three cervical cancer cell lines, HeLa, CaSki, and C33A, representing major molecular subtypes of cervical cancer and xenografts. We found that Mzb alone showed noteworthy cytotoxic effects, and its combination with CDDP resulted in more obvious cytotoxicity and apoptosis in cervical cancer cell lines and xenografts. In order to investigate the mechanism of this effect, we probed whether Mzb alone or in combination with CDDP had a better antitumor response by enhancing CDDP-induced angiopoietin 1 (Ang-1) expression and inhibiting the expression of TEK receptor tyrosine kinase (Tie-2) in the Ang-1/Tie-2 pathway, FMS-like tyrosine kinase 3 ligand (Flt-3L) and stem cell factor (SCF) as identified by a cytokine antibody chip test. The results suggest that Mzb has better antitumor effects on cervical cancer cells and can sensitize cervical cancer cells to CDDP treatment both in vitro and in vivo. Accordingly, we conclude that the combination of CDDP with Mzb produces synergistic anticancer activity and that Mzb may be a potential effective drug in combination therapy for cervical cancer patients.

Downregulation of S100A9 Reverses Cisplatin-Resistance and Inhibits Proliferation and Migration in Hypopharyngeal Carcinoma

Purpose

Patients with hypopharyngeal carcinoma (HPC) often progress to an advanced clinical stage at diagnosis. Cisplatin has been widely used in first-line chemotherapy for advanced HPC. However, acquired chemotherapeutic resistance leads to recurrence, metastasis, and a poor survival rate. Therefore, identifying new drug targets to improve treatment effects is still in need.

Methods

To screen the differential expression genes (DEGs) and proteins (DEPs), we conducted transcriptomic and proteomic analysis on cisplatin-sensitive cell lines (FaDu) and cisplatin-resistant cell lines (FaDu/DDP) of hypopharyngeal carcinoma. DEGs and DEPs, possibly the most associated with cisplatin-resistance, were verified by real-time polymerase chain reaction (RT-PCR) and western blot (WB), respectively, and the biological function of the screened S100A9 was further tested by CCK8, wound healing, and transwell assays.

Results

We identified S100A9 as a target for resensitizing the response to cisplatin in an acquired resistance model. S100A9 overexpression was significantly related to cisplatin resistance. Functional studies in vitro models demonstrated that downregulation of S100A9 overcame cisplatin-resistance and inhibited proliferation and migration. Later, we verified that downregulation of S100A9 suppressed the interleukin-6 (IL6) expression and epithelial-mesenchymal transition (EMT) pathway.

Conclusion

In all, S100A9 plays a crucial role in cisplatin-resistance, proliferation, and migration of HPC. Targeting S100A9 may become a novel strategy for the treatment of HPC.

CRISPR/Cas9-based genome-wide screening for deubiquitinase subfamily identifies USP1 regulating MAST1-driven cisplatin-resistance in cancer cells

Background: Cisplatin is one of the frontline anticancer agents. However, development of cisplatin-resistance limits the therapeutic efficacy of cisplatin-based treatment. The expression of microtubule-associated serine/threonine kinase 1 (MAST1) is a primary factor driving cisplatin-resistance in cancers by rewiring the MEK pathway. However, the mechanisms responsible for MAST1 regulation in conferring drug resistance is unknown.

Methods: We implemented a CRISPR/Cas9-based, genome-wide, dual screening system to identify deubiquitinating enzymes (DUBs) that govern cisplatin resistance and regulate MAST1 protein level. We analyzed K48- and K63-linked polyubiquitination of MAST1 protein and mapped the interacting domain between USP1 and MAST1 by immunoprecipitation assay. The deubiquitinating effect of USP1 on MAST1 protein was validated using rescue experiments, in vitro deubiquitination assay, immunoprecipitation assays, and half-life analysis. Furthermore, USP1-knockout A549 lung cancer cells were generated to validate the deubiquitinating activity of USP1 on MAST1 abundance. The USP1-MAST1 correlation was evaluated using bioinformatics tool and in different human clinical tissues. The potential role of USP1 in regulating MAST1-mediated cisplatin resistance was confirmed using a series of in vitro and in vivo experiments. Finally, the clinical relevance of the USP1-MAST1 axis was validated by application of small-molecule inhibitors in a lung cancer xenograft model in NSG mice.

Results: The CRISPR/Cas9-based dual screening system identified USP1 as a novel deubiquitinase that interacts, stabilizes, and extends the half-life of MAST1 by preventing its K48-linked polyubiquitination. The expression analysis across human clinical tissues revealed a positive correlation between USP1 and MAST1. USP1 promotes MAST1-mediated MEK1 activation as an underlying mechanism that contributes to cisplatin-resistance in cancers. Loss of USP1 led to attenuation of MAST1-mediated cisplatin-resistance both in vitro and in vivo. The combined pharmacological inhibition of USP1 and MAST1 using small-molecule inhibitors further abrogated MAST1 level and synergistically enhanced cisplatin efficacy in a mouse xenograft model.

Conclusions: Overall, our study highlights the role of USP1 in the development of cisplatin resistance and uncovers the regulatory mechanism of MAST1-mediated cisplatin resistance in cancers. Co-treatment with USP1 and MAST1 inhibitors abrogated tumor growth and synergistically enhanced cisplatin efficacy, suggesting a novel alternative combinatorial therapeutic strategy that could further improve MAST1-based therapy in patients with cisplatin-resistant tumors.