Cellular responses to Cisplatin-induced DNA damage

Ergothioneine mitigates cisplatin-evoked nephrotoxicity via targeting Nrf2, NF-κB, and apoptotic signaling and inhibiting γ-glutamyl transpeptidase

AIM

Cisplatin is a potent chemotherapeutic agent whose therapeutic application is hindered by the associated nephrotoxicity. Cisplatin-evoked nephrotoxicity has been largely attributed to the induction of oxidative stress and inflammatory responses. The current study aimed at investigating the ability of ergothioneine to mitigate cisplatin-evoked nephrotoxicity and to elucidate the underlining molecular mechanisms.

MAIN METHODS

Wistar rats were treated with a daily dose of ergothioneine (70 mg/kg, po) for fourteen days and a single dose of cisplatin (5 mg/kg, ip) on day ten. On day fifteen, kidneys and blood specimens were collected and subjected to Western blotting, ELISA, histopathological, and spectrophotometric analysis.

KEY FINDINGS

Ergothioneine significantly enhanced renal function in cisplatin-treated rats as manifested by increased GFR and decreased serum creatinine and blood urea nitrogen. Ergothioneine effectively reduced the cisplatin-induced oxidative stress and mitigated apoptosis and the histopathological changes. Mechanistically, ergothioneine induced the expression of the antioxidant transcription factor Nrf2 and up-regulated its downstream targets NQO1 and HO-1. Equally important, ergothioneine inhibited γ-glutamyl transpeptidase that plays crucial roles in biotransformation of cisplatin into a toxic metabolite. Additionally, it reduced the pro-apoptotic protein p53 and the inflammatory transcription factor NF-κB along with its downstream pro-inflammatory cytokines TNF-α and IL-1β.

SIGNIFICANCE

The results of the current work shed the light on the ameliorating effect of ergothioneine on cisplatin-evoked nephrotoxicity that is potentially mediated through modulation of Nrf2, p53, and NF-κB signaling and inhibition of γ-glutamyl transpeptidase. This findings support the potential application of ergothioneine in controlling cisplatin-associated nephrotoxicity although clinical investigations are warranted.

The Synergistic Combination of Cisplatin and Piperine Induces Apoptosis in MCF-7 Cell Line

Background

Piperine is a natural compound obtained from the Piper nigrum that exhibits anti-proliferative and anti-cancer activity in cancer cell lines. We analyzed the cytotoxic effect of piperine combined with cisplatin compound in the human MCF-7 breast cancer cell line and the underlying mechanism.

Methods

The present in vitro study was performed on MCF-7 cell line in Jahrom University of Medical Sciences between, Jahrom, Iran from 2016 to 2017. Cultured MCF-7 cells were seeded into four groups: a control group (untreated group), a group treated with cisplatin, a group treated with piperine and a group treated with cisplatin and piperine. Cell viability was analyzed using the MTT assay method. Flow c-ytometric analysis was investigated for apoptosis. The mRNA and protein expression of the apoptotic regulators p53, Bcl-2, Bax, caspase 3 and caspase 9 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting analysis.

Results

Piperine (20 and 30 μM) in combination with cisplatin (5, 10 and 15 μM) for 24 h synergistically inhibited cell viability of MCF-7 breast cancer cells more than piperine and cisplatin used alone. Synergistic anti-breast cancer activities cisplatin (5 μM) and piperine (20 μM) were via inducing apoptosis. Piperine (20 μM) and cisplatin (5 μM) for 24 h induce apoptosis strongly through reduction of Bcl-2 and increase of caspase 3, p53, caspase 9, and Bax.

Conclusion

Piperine in combination with cisplatin could trigger p53-mediated apoptosis more effective than cisplatin alone in MCF-7 breast cancer cells, reducing the toxic dose of cisplatin used in cancer chemotherapy.

Captopril downregulates expression of Bax/cytochrome C/caspase-3 apoptotic pathway, reduces inflammation, and oxidative stress in cisplatin-induced acute hepatic injury

Cisplatin (Cis) is an effective cancer therapy commonly employed in many therapeutic regimens. However, treatment regimens that contain either a high dose or cumulative doses of Cis could trigger liver damage. A unique study demonstrated that captopril (Cap) protects against Cis-induced liver toxicity, but only some liver function enzymes and some antioxidant enzymes were investigated in that study. Our study aims to elucidate the protective mechanism of Cap against Cis liver toxicity. Acute liver toxicity was induced in rats by injecting a single Cis dose (7.5 mg/kg) in three groups (n = 6). Two groups were pre-treated with low (50 mg/kg) and high (100 mg/kg) Cap doses for one week before Cis injection, and the third group was injected with Cis only. The high Cap dose significantly improved liver function markers (ALT, AST, and ALP) and hepatic tissue pathology. The low Cap dose significantly improved ALP and, to a lesser extent, hepatic tissue pathology. Both Cap doses significantly decreased liver contents of MDA, IL-1β, and cleaved caspase-3; and liver protein expression of TNF-α, Bax, and caspase-3. The high Cap dose significantly increased liver contents of GSH, GPx, CAT, and SOD, and the liver protein expression of Bcl2. Moreover, only the high Cap dose significantly decreased liver IL-6 content and cytochrome C protein expression. Cap did not inhibit the antitumor impact of Cis against HCT116 cancer cells. Therefore, Cap restricts Cis-induced liver toxicity by reducing inflammation and apoptosis and augmenting the antioxidant system.

Platinum Complexes in Colorectal Cancer and Other Solid Tumors

Simple Summary

Cisplatin is successfully used for the treatment of various solid cancers. Unfortunately, it shows no activity in colorectal cancer. The resistance phenotype of colorectal cancer cells is mainly caused by alterations in p53-controlled DNA damage signaling and/or defects in the cellular mismatch repair pathway. Improvement of platinum-based chemotherapy in cisplatin-unresponsive cancers, such as colorectal cancer, might be achieved by newly designed cisplatin analogues, which retain activity in unresponsive tumor cells. Moreover, a combination of cisplatin with biochemical modulators of DNA damage signaling might sensitize cisplatin-resistant tumor cells to the drug, thus providing another strategy to improve cancer therapy.

Abstract

Cisplatin is one of the most commonly used drugs for the treatment of various solid neoplasms, including testicular, lung, ovarian, head and neck, and bladder cancers. Unfortunately, the therapeutic efficacy of cisplatin against colorectal cancer is poor. Various mechanisms appear to contribute to cisplatin resistance in cancer cells, including reduced drug accumulation, enhanced drug detoxification, modulation of DNA repair mechanisms, and finally alterations in cisplatin DNA damage signaling preventing apoptosis in cancer cells. Regarding colorectal cancer, defects in mismatch repair and altered p53-mediated DNA damage signaling are the main factors controlling the resistance phenotype. In particular, p53 inactivation appears to be associated with chemoresistance and poor prognosis. To overcome resistance in cancers, several strategies can be envisaged. Improved cisplatin analogues, which retain activity in resistant cancer, might be applied. Targeting p53-mediated DNA damage signaling provides another therapeutic strategy to circumvent cisplatin resistance. This review provides an overview on the DNA repair pathways involved in the processing of cisplatin damage and will describe signal transduction from cisplatin DNA lesions, with special attention given to colorectal cancer cells. Furthermore, examples for improved platinum compounds and biochemical modulators of cisplatin DNA damage signaling will be presented in the context of colon cancer therapy.

Regulation of Cellular and Cancer Stem Cell-Related Putative Gene Expression of Parental and CD44+CD24- Sorted MDA-MB-231 Cells by Cisplatin

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that promotes a higher risk of metastasis and cancer reoccurrence. Cisplatin is one of the potential anticancer drugs for treating TNBC. However, the occurrence of cisplatin resistance still remains one of the challenges in fully eradicating TNBC. The presence of cancer stem cells (CSCs) has been proposed as one of the factors contributing to the development of cisplatin resistance. In this study, we aimed to characterize the cellular properties and reveal the corresponding putative target genes involved in cisplatin resistance associated with CSCs using the TNBC cell line (MDA-MB-231). CSC-like cells were isolated from parental cells and the therapeutic effect of cisplatin on CSC-like cells was compared to that of the parental cells via cell characterization bioassays. A PCR array was then conducted to study the expression of cellular mRNA for each subpopulation. As compared to treated parental cells, treated CSCs displayed lower events of late apoptosis/necrosis and G2/M phase cell arrest, with higher mammosphere formation capacity. Furthermore, a distinct set of putative target genes correlated to the Hedgehog pathway and angiogenesis were dysregulated solely in CSC-like cells after cisplatin treatment, which were closely related to the regulation of chemoresistance and self-renewability in breast cancer. In summary, both cellular and gene expression studies suggest the attenuated cytotoxicity of cisplatin in CSC-like cells as compared to parental cells. Understanding the role of dysregulated putative target genes induced by cisplatin in CSCs may aid in the potential development of therapeutic targets for cisplatin-resistant breast cancer.

Tumor hypoxia: The major culprit behind cisplatin resistance in cancer patients

Cisplatin is the most commonly used first-line drug for cancer treatment. However, many patients develop resistance to cisplatin therapy which ultimately results in therapy failure and increased mortality. A growing body of evidence shows that the hypoxic microenvironment is the prime factor underlying tumor insensitivity to cisplatin treatment. Since tumors in the majority of cancer patients are under hypoxic stress (low oxygen supply), it becomes necessary to understand the pathobiology behind hypoxia-induced cisplatin resistance in cancer cells. Here, we discuss the molecular events that render hypoxic tumors insensitive to cisplatin therapy. Furthermore, various drugs and tumor oxygenation techniques have been developed to circumvent cisplatin resistance in hypoxic tumors. However, their pharmaceutical applications are limited due to failures in clinical investigations and a lack of preclinical studies in the hypoxic tumor microenvironment. This review addresses these challenges and provides new directions for the strategic deployment of cisplatin sensitizers in the hypoxic tumor microenvironment.

Mixed-Ligand Cobalt(III) Complexes of a Naturally Occurring Coumarin and Phenanthroline Bases as Mitochondria-Targeted Dual-Purpose Photochemotherapeutics

The bioessential nature of cobalt and the rich photochemistry of its coordination complexes can be exploited to develop potential next-generation photochemotherapeutics. A series of six novel mixed-ligand cobalt(III) complexes of the formulation [Co(B)₂(L)]ClO₄ (1-6), where B is an N,N-donor phenanthroline base, namely, 1,10-phenanthroline (phen in 1 and 4), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2 and 5), and dipyrido[3,2-a:2',3'-c]phenazine (dppz in 3 and 6), and L is an O,O-donor dianionic ligand derived from catechol (1,2-dihydroxybenzene, cat^2-, in 1-3) or esculetin (6,7-dihydoxycoumarin, esc^2-, in 4-6), have been prepared and characterized, and their light-triggered cytotoxicity has been studied in cancer cells. The single-crystal X-ray diffraction structures of complexes 1 (as PF₆^- salt, 1a) and 2 show distorted octahedral geometries around the cobalt(III) center formed by the set of N₄O₂ donor atoms. The low-spin and 1:1 electrolytic complexes 1-6 display a d-d transition around 700 nm. Complexes 4-6 with a coordinated esc^2- ligand additionally display a π → π* intraligand transition centered at 403 nm. Complexes 4-6 possessing a naturally occurring and photoactive esc^2- ligand show high visible-light-triggered cytotoxicity against HeLa and MCF-7 cancer cells, yielding remarkably low micromolar IC₅₀ values while being much less toxic under dark conditions. Control complexes 1-3 possessing the photoinactive cat^2- ligand show significantly less cytotoxicity either in the presence of light or in the dark. The complex-induced cell death is apoptotic in nature caused by the formation of reactive oxygen species via a type 1 photoredox pathway. Fluorescence microscopy of HeLa cells treated with complex 6 reveals mitochondrial localization of the complex. A significant decrease in the dark toxicity of free esculetin and dppz base is observed upon coordination to cobalt(III). Complexes bind to calf-thymus DNA with significant affinity, but 6 binds with the greatest affinity. Complex 6 efficiently photocleaves supercoiled DNA to its nicked circular form when irradiated with visible light via a photoredox type 1 pathway involving hydroxyl radicals (HO^•). Thus, complex 6 showing remarkable visible-light-triggered cytotoxicity but negligible toxicity in the dark is a good candidate for cancer photochemotherapy applications.

DNA repair pathways and their roles in drug resistance for lung adenocarcinoma

Lung cancer is the leading cancer type of death rate. The lung adenocarcinoma subtype is responsible for almost half of the total lung cancer deaths. Despite the improvements in cancer treatment in recent years, lung adenocarcinoma patients' overall survival rate remains poor. Immunetherapy and chemotherapy are two of the most widely used options for the treatment of cancer. Although many cancer types initially respond to these treatments, the development of resistance is inevitable. The rapid development of drug resistance mainly characterizes lung adenocarcinoma. Despite being the subject of many studies in recent years, the resistance initiation and progression mechanism is still unclear. In this review, we have examined the role of the primary DNA repair pathways (non-homologous end joining (NHEJ) pathway, homologous-recombinant repair (HR) pathway, base excision repair (BER) pathway, and nucleotide excision repair (NER) pathway and transactivation mechanisms of tumor protein 53 (TP53) in drug resistance development. This review suggests that mentioned pathways have essential roles in developing the resistance against chemotherapy and immunotherapy in lung adenocarcinoma patients.

Chloroxine overrides DNA damage tolerance to restore platinum sensitivity in high-grade serous ovarian cancer

High-grade serous cancer (HGSC) accounts for ~67% of all ovarian cancer deaths. Although initially sensitive to platinum chemotherapy, resistance is inevitable and there is an unmet clinical need for novel therapies that can circumvent this event. We performed a drug screen with 1177 FDA-approved drugs and identified the hydroxyquinoline drug, chloroxine. In extensive validation experiments, chloroxine restored sensitivity to both cisplatin and carboplatin, demonstrating broad synergy in our range of experimental models of platinum-resistant HGSC. Synergy was independent of chloroxine's predicted ionophore activity and did not relate to platinum uptake as measured by atomic absorption spectroscopy. Further mechanistic investigation revealed that chloroxine overrides DNA damage tolerance in platinum-resistant HGSC. Co-treatment with carboplatin and chloroxine (but not either drug alone) caused an increase in γH2AX expression, followed by a reduction in platinum-induced RAD51 foci. Moreover, this unrepaired DNA damage was associated with p53 stabilisation, cell cycle re-entry and triggering of caspase 3/7-mediated cell death. Finally, in our platinum-resistant, intraperitoneal in vivo model, treatment with carboplatin alone resulted in a transient tumour response followed by tumour regrowth. In contrast, treatment with chloroxine and carboplatin combined, was able to maintain tumour volume at baseline for over 4 months. In conclusion, our novel results show that chloroxine facilitates platinum-induced DNA damage to restore platinum sensitivity in HGSC. Since chloroxine is already licensed, this exciting combination therapy could now be rapidly translated for patient benefit.

FLYWCH1, a Multi-Functional Zinc Finger Protein Contributes to the DNA Repair Pathway

Over recent years, several Cys2-His2 (C2H2) domain-containing proteins have emerged as critical players in repairing DNA-double strand breaks. Human FLYWCH1 is a newly characterised nuclear transcription factor with (C2H2)-type zinc-finger DNA-binding domains. Yet, our knowledge about FLYWCH1 is still in its infancy. This study explores the expression, role and regulation of FLYWCH1 in the context of DNA damage and repair. We provide evidence suggesting a potential contribution of FLYWCH1 in facilitating the recruitment of DNA-damage response proteins (DDRPs). We found that FLYWCH1 colocalises with γH2AX in normal fibroblasts and colorectal cancer (CRC) cell lines. Importantly, our results showed that enforced expression of FLYWCH1 induces the expression of γH2AX, ATM and P53 proteins. Using an ATM-knockout (ATM^KO) model, we indicated that FLYWCH1 mediates the phosphorylation of H2AX (Ser139) independently to ATM expression. On the other hand, the induction of DNA damage using UV-light induces the endogenous expression of FLYWCH1. Conversely, cisplatin treatment reduces the endogenous level of FLYWCH1 in CRC cell lines. Together, our findings uncover a novel FLYWCH1/H2AX phosphorylation axis in steady-state conditions and during the induction of the DNA-damage response (DDR). Although the role of FLYWCH1 within the DDR machinery remains largely uncharacterised and poorly understood, we here report for the first-time findings that implicate FLYWCH1 as a potential participant in the DNA damage response signaling pathways.

Gold(III) complexes with thiosemicarbazonate ligands as potential anticancer agents: Cytotoxicity and interactions with biomolecular targets

Gold(III) complexes have been studied for the past years due to their anticancer properties and great affinity to biotargets, such as enzymes and proteins, which support their pharmacological applications. Within this scope, in this work the antiproliferative activities of two Au(III)-thiosemicarbazonate complexes, [AuClL₁] (1, L₁: (E,Z)-N-ethyl-N'-(3-nitroso-kN)butan-2-ylidene)carbamohydrazonothioato-k²N²,S) and [Au(Hdamp)L₂]Cl (2, L₂: N-(N'',N''-diethylaminothiocarbonyl)-N'(N''', N'''-dimethylcarbothioamide)benzamidineto-kN,k²S and Hdamp: 2-(N,N-dimethylaminomethyl)-phenyl-C¹), and their affinities to possible biological targets were investigated. Three different tumor cell lines were used to perform the cytotoxicity assays, including one cisplatin-resistant model, and the results showed lower EC₅₀ for 1 over 2 in every case: B16F10 (4.1 μM and 15.6 μM), A431 (4.0 μM and >50 μM) and OVCAR3 (4.2 μM and 24.5 μM). However, a lower toxicity to fibroblast 3T3 cell line was observed for 2 (30.58 μM) when compared to 1 (7.17 μM), resulting in comparable therapeutic indexes. Both complexes presented strong affinity to HSA: they distorted the secondary structure of the protein, as verified by circular dichroism, but 1 additionally presented the apparent fluorescence quenching constant (K_app) ten times greater than 2, which was probably due to the fact of 1 being able to denature HSA. The ethidium bromide displacement assay showed that neither 1 nor 2 are strong DNA intercalators, which is in agreement with what was observed through the UV-vis titration. In both cases, the 260 nm band presented hyperchromism, which can indicate ionic interactions or DNA damage. In fact, 1 was able to damage the pGEM plasmid, similarly to cisplatin, as verified by agarose gel electrophoresis and Atomic Force Microscopy. Biophysical studies in cancer cells model membranes were also performed in order to investigate the interaction of the gold complexes to lipid bilayers and revealed that the compounds interact with the membranes by exhibiting partition coefficients of 10³ order of magnitude. Overall, both complexes were found to be promising candidates for the development of a future anticancer drug against low sensitive or cisplatin resistant tumors.

The Winged Helix Domain of CSB Regulates RNAPII Occupancy at Promoter Proximal Pause Sites

Cockayne syndrome group B protein (CSB), a member of the SWI/SNF superfamily, resides in an elongating RNA polymerase II (RNAPII) complex and regulates transcription elongation. CSB contains a C-terminal winged helix domain (WHD) that binds to ubiquitin and plays an important role in DNA repair. However, little is known about the role of the CSB-WHD in transcription regulation. Here, we report that CSB is dependent upon its WHD to regulate RNAPII abundance at promoter proximal pause (PPP) sites of several actively transcribed genes, a key step in the regulation of transcription elongation. We show that two ubiquitin binding-defective mutations in the CSB-WHD, which impair CSB's ability to promote cell survival in response to treatment with cisplatin, have little impact on its ability to stimulate RNAPII occupancy at PPP sites. In addition, we demonstrate that two cancer-associated CSB mutations, which are located on the opposite side of the CSB-WHD away from its ubiquitin-binding pocket, impair CSB's ability to promote RNAPII occupancy at PPP sites. Taken together, these results suggest that CSB promotes RNAPII association with PPP sites in a manner requiring the CSB-WHD but independent of its ubiquitin-binding activity. These results further imply that CSB-mediated RNAPII occupancy at PPP sites is mechanistically separable from CSB-mediated repair of cisplatin-induced DNA damage.

NEK1 deficiency affects mitochondrial functions and the transcriptome of key DNA repair pathways

Previous studies have indicated important roles for NIMA-related kinase 1 (NEK1) in modulating DNA damage checkpoints and DNA repair capacity. To broadly assess the contributions of NEK1 to genotoxic stress and mitochondrial functions, we characterised several relevant phenotypes of NEK1 CRISPR knockout (KO) and wild-type (WT) HAP1 cells. Our studies revealed that NEK1 KO cells resulted in increased apoptosis and hypersensitivity to the alkylator methyl methanesulfonate, the radiomimetic bleomycin and UVC light, yet increased resistance to the crosslinker cisplatin. Mitochondrial functionalities were also altered in NEK1 KO cells, with phenotypes of reduced mitophagy, increased total mitochondria, elevated levels of reactive oxygen species, impaired complex I activity and higher amounts of mitochondrial DNA damage. RNA-seq transcriptome analysis coupled with quantitative real-time PCR studies comparing NEK1 KO cells with NEK1 overexpressing cells revealed that the expression of genes involved in DNA repair pathways, such as base excision repair, nucleotide excision repair and double-strand break repair, are altered in a way that might influence genotoxin resistance. Together, our studies underline and further support that NEK1 serves as a hub signalling kinase in response to DNA damage, modulating DNA repair capacity, mitochondrial activity and cell fate determination.

Advances in Our Understanding of the Molecular Mechanisms of Action of Cisplatin in Cancer Therapy

Cisplatin and other platinum-based chemotherapeutic drugs have been used extensively for the treatment of human cancers such as bladder, blood, breast, cervical, esophageal, head and neck, lung, ovarian, testicular cancers, and sarcoma. Cisplatin is commonly administered intravenously as a first-line chemotherapy for patients suffering from various malignancies. Upon absorption into the cancer cell, cisplatin interacts with cellular macromolecules and exerts its cytotoxic effects through a series of biochemical mechanisms by binding to Deoxyribonucleic acid (DNA) and forming intra-strand DNA adducts leading to the inhibition of DNA synthesis and cell growth. Its primary molecular mechanism of action has been associated with the induction of both intrinsic and extrinsic pathways of apoptosis resulting from the production of reactive oxygen species through lipid peroxidation, activation of various signal transduction pathways, induction of p53 signaling and cell cycle arrest, upregulation of pro-apoptotic genes/proteins, and down-regulation of proto-oncogenes and anti-apoptotic genes/proteins. Despite great clinical outcomes, many studies have reported substantial side effects associated with cisplatin monotherapy, while others have shown substantial drug resistance in some cancer patients. Hence, new formulations and several combinational therapies with other drugs have been tested for the purpose of improving the clinical utility of cisplatin. Therefore, this review provides a comprehensive understanding of its molecular mechanisms of action in cancer therapy and discusses the therapeutic approaches to overcome cisplatin resistance and side effects.

Mechanisms of resistance to chemotherapy in non-small cell lung cancer

Non-small cell lung cancer (NSCLC), which represents 80-85% of lung cancer cases, is one of the leading causes of human death worldwide. The majority of patients undergo an intensive and invasive treatment regimen, which may include radiotherapy, chemotherapy, targeted therapy, immunotherapy, or a combination of these, depending on disease stage and performance status. Despite advances in therapeutic regimens, the 5-year survival of NSCLC is approximately 20-30%, largely due to diagnosis at advanced stages. Conventional chemotherapy is still the standard treatment option for patients with NSCLC, especially those with advanced disease. However, the emergence of resistance to chemotherapeutic agents (chemoresistance) poses a significant obstacle to the management of patients with NSCLC. Therefore, to develop efficacious chemotherapeutic approaches for NSCLC, it is necessary to understand the mechanisms underlying chemoresistance. Several mechanisms are known to mediate chemoresistance. These include altered cellular targets for chemotherapy, decreased cellular drug concentrations, blockade of chemotherapy-induced cell cycle arrest and apoptosis, acquisition of epithelial-mesenchymal transition and cancer stem cell-like phenotypes, deregulated expression of microRNAs, epigenetic modulation, and the interaction with tumor microenvironments. In this review, we summarize the mechanisms underlying chemoresistance and tumor recurrence in NSCLC and discuss potential strategies to avoid or overcome chemoresistance.

Mechanisms of Cisplatin in Combination with Repurposed Drugs against Human Endometrial Carcinoma Cells

Although endometrial carcinoma is one of the most common gynecological malignancies worldwide, its precise etiology remains unknown. Moreover, no novel adjuvant and/or targeted therapies are currently being developed to achieve greater efficacy for endometrial cancer patients who develop chemotherapeutic drug resistance. In this study, we used three human endometrial cancer cell lines, RL95-2, HEC-1-A, and KLE, to investigate the responsiveness of cisplatin alone and in combination with potential repurposed drugs. We first found that RL95-2 cells were more sensitive to cisplatin than HEC-1-A or KLE cells. The cytotoxicity of cisplatin in RL95-2 cells may reflect its ability to perturb the cell cycle, reactive oxygen species production and autophagy as well as to induce senescence and DNA damage. Similar effects, although not DNA damage, were also observed in HEC-1-A and KLE cells. In addition, downregulation of p53 and/or cyclin D1 may also impact the responsiveness of HEC-1-A and KLE cells to cisplatin. We also observed that resveratrol, trichostatin A (TSA), caffeine, or digoxin increased the apoptotic process of cisplatin toward RL95-2 cells, while amiodarone or TSA increased its apoptotic process toward HEC-1-A cells. The combination index supported the assertion that the combination of cisplatin with caffeine, amiodarone, resveratrol, metformin, digoxin, or TSA increases the cytotoxicity of cisplatin in HEC-1-A cells. These findings suggest potential strategies for enhancing the efficacy of cisplatin to overcome drug resistance in endometrial carcinoma patients.

SILAC-Based Quantitative Proteomic Analysis of Oxaliplatin-Resistant Pancreatic Cancer Cells

Simple Summary

Resistance to oxaliplatin remains a major challenge in pancreatic cancer therapy. However, molecular mechanisms underlying oxaliplatin resistance in pancreatic cancer is still unclear. The aim of this study was to identify global changes of proteins involved in oxaliplatin resistance in pancreatic cancer cells, thereby elucidating the multiple mechanisms of oxaliplatin resistance in pancreatic cancer. We presented the quantitative proteomic profiling of oxaliplatin-resistant pancreatic cancer cells via a stable isotope labelling by amino acids in cell culture (SILAC)-based shotgun proteomic approach. Multiple biological processes including DNA repair, cell cycle process, and type I interferon signaling pathway were enriched in oxaliplatin-resistant pancreatic cancer cells. Furthermore, we demonstrated that both Wntless homolog protein (WLS) and myristoylated alanine-rich C-kinase substrate (MARCKS) could participate in oxaliplatin resistance in pancreatic cancer cells.

Abstract

Oxaliplatin is a commonly used chemotherapeutic drug for the treatment of pancreatic cancer. Understanding the cellular mechanisms of oxaliplatin resistance is important for developing new strategies to overcome drug resistance in pancreatic cancer. In this study, we performed a stable isotope labelling by amino acids in cell culture (SILAC)-based quantitative proteomics analysis of oxaliplatin-resistant and sensitive pancreatic cancer PANC-1 cells. We identified 107 proteins whose expression levels changed (thresholds of 2-fold changes and p-value ≤ 0.05) between oxaliplatin-resistant and sensitive cells, which were involved in multiple biological processes, including DNA repair, cell cycle process, and type I interferon signaling pathway. Notably, myristoylated alanine-rich C-kinase substrate (MARCKS) and Wntless homolog protein (WLS) were upregulated in oxaliplatin-resistant cells compared to sensitive cells, as confirmed by qRT-PCR and Western blot analysis. We further demonstrated the activation of AKT and β-catenin signaling (downstream targets of MARCKS and WLS, respectively) in oxaliplatin-resistant PANC-1 cells. Additionally, we show that the siRNA-mediated suppression of both MARCKS and WLS enhanced oxaliplatin sensitivity in oxaliplatin-resistant PANC-1 cells. Taken together, our results provide insights into multiple mechanisms of oxaliplatin resistance in pancreatic cancer cells and reveal that MARCKS and WLS might be involved in the oxaliplatin resistance.

Suppressed Hepatic Production of Indoxyl Sulfate Attenuates Cisplatin-Induced Acute Kidney Injury in Sulfotransferase 1a1-Deficient Mice

Endogenous factors involved in the progression of cisplatin nephropathy remain undetermined. Here, we demonstrate the toxico-pathological roles of indoxyl sulfate (IS), a sulfate-conjugated uremic toxin, and sulfotransferase 1A1 (SULT1A1), an enzyme involved in its synthesis, in cisplatin-induced acute kidney injury using Sult1a1-deficient (Sult1a1^-/- KO) mice. With cisplatin administration, severe kidney dysfunction, tissue damage, and apoptosis were attenuated in Sult1a1^-/- (KO) mice. Aryl hydrocarbon receptor (AhR) expression was increased by treatment with cisplatin in mouse kidney tissue. Moreover, the downregulation of antioxidant stress enzymes in wild-type (WT) mice was not observed in Sult1a1^-/- (KO) mice. To investigate the effect of IS on the reactive oxygen species (ROS) levels, HK-2 cells were treated with cisplatin and IS. The ROS levels were significantly increased compared to cisplatin or IS treatment alone. IS-induced increases in ROS were reversed by downregulation of AhR, xanthine oxidase (XO), and NADPH oxidase 4 (NOX4). These findings suggest that SULT1A1 plays toxico-pathological roles in the progression of cisplatin-induced acute kidney injury, while the IS/AhR/ROS axis brings about oxidative stress.

Cisplatin Cytotoxicity in Human Testicular Germ Cell Tumor Cell Lines Is Enhanced by the CDK4/6 Inhibitor Palbociclib

BACKGROUND

Cisplatin-based chemotherapy is the mainstay of pharmacological treatment of testicular germ cell tumors (TGCTs) that, together with early diagnosis, surgery, and/or radiotherapy, has dramatically improved the prognosis. However, under the pressure of such pharmacological therapy (both classical cytotoxic drugs and targeted therapy), cancer cells may develop resistance. Thus, combination therapy that may include cytotoxic drugs and targeted therapy could offer an advantage to curing cancers. Here, we investigated the in vitro and in vivo antitumor activity of cisplatin, as a single-agent or in combination with palbociclib.

PATIENTS AND METHODS

The cell viability of Ntera-2/cl.D1 (NT2/D1) and 833K after exposure to palbociclib and/or cisplatin was evaluated by MTT dye reduction assay and by ATPLite Luminescence Assay. Gene and protein expression was evaluated by quantitative reverse transcription polymerase chain reaction and by western blot. Flow cytometric cell-cycle analysis was performed, as well. The in vivo experiments were conducted on NT2/D1 xenografts in AB zebrafish embryos exposed to the drugs.

RESULTS

Palbociclib and cisplatin decreased TGCT cell viability both in vitro and in vivo. This effect was additive when cells were exposed to the drug combination. In the NT2/D1 cell lines, the drug combination also exerted a positive effect with regard to delaying cell recovery after the toxic insult. In the combination experiments, cisplatin-induced cell accumulation in G2/M was predominant compared with the palbociclib effect.

CONCLUSIONS

These results could provide the rationale for developing further studies to improve the pharmacological treatment of TGCTs, but they must be demonstrated in a dedicated clinical trial.

Inhibition of Kpnβ1 mediated nuclear import enhances cisplatin chemosensitivity in cervical cancer

Background

Inhibition of nuclear import via Karyopherin beta 1 (Kpnβ1) shows potential as an anti-cancer approach. This study investigated the use of nuclear import inhibitor, INI-43, in combination with cisplatin.

Methods

Cervical cancer cells were pre-treated with INI-43 before treatment with cisplatin, and MTT cell viability and apoptosis assays performed. Activity and localisation of p53 and NFκB was determined after co-treatment of cells.

Results

Pre-treatment of cervical cancer cells with INI-43 at sublethal concentrations enhanced cisplatin sensitivity, evident through decreased cell viability and enhanced apoptosis. Kpnβ1 knock-down cells similarly displayed increased sensitivity to cisplatin. Combination index determination using the Chou-Talalay method revealed that INI-43 and cisplatin engaged in synergistic interactions. p53 was found to be involved in the cell death response to combination treatment as its inhibition abolished the enhanced cell death observed. INI-43 pre-treatment resulted in moderately stabilized p53 and induced p53 reporter activity, which translated to increased p21 and decreased Mcl-1 upon cisplatin combination treatment. Furthermore, cisplatin treatment led to nuclear import of NFκB, which was diminished upon pre-treatment with INI-43. NFκB reporter activity and expression of NFκB transcriptional targets, cyclin D1, c-Myc and XIAP, showed decreased levels after combination treatment compared to single cisplatin treatment and this associated with enhanced DNA damage.

Conclusions

Taken together, this study shows that INI-43 pre-treatment significantly enhances cisplatin sensitivity in cervical cancer cells, mediated through stabilization of p53 and decreased nuclear import of NFκB. Hence this study suggests the possible synergistic use of nuclear import inhibition and cisplatin to treat cervical cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07819-3.

Implantable Cisplatin Synthesis Microdevice for Regional Chemotherapy

Cisplatin, the first platinum chemotherapy agent to obtain Food and Drug Administration (FDA) approval in 1978, is widely used for a number of cancers. However, the painful side effects stemming from systemic delivery are the inevitable limitation of cisplatin. A possible solution is regional chemotherapy using various drug delivery systems, which reduces the systemic toxicity and increases drug accumulation in the tumor. In this paper, a rice-grain sized, ultrasonically powered, and implantable microdevice that can synthesize cisplatin in situ is presented. The microdevice produces 0.7 mg of cisplatin within 1 h under ultrasonic irradiation (400 mW cm^-2 ). The effect of the microdevice-synthesized cisplatin is evaluated using in vitro murine breast cancer cells and ex vivo liver tissue. The results suggest that cytotoxic activities of the microdevice-mediated cisplatin delivery are significantly higher in both in vitro and ex vivo experiments. Overall, the proposed cisplatin synthesis microdevice represents a strong alternative treatment option for regional chemotherapy.

p38 Mitogen-activated protein kinase modulates cisplatin resistance in Head and Neck Squamous Cell Carcinoma cells

OBJECTIVE

This study aims to investigate the role of p38 Mitogen-activated protein kinase (MAPK) in imparting cisplatin resistance in head and neck squamous cell carcinoma (HNSCC) cells.

DESIGN

Laboratory generated cisplatin resistant HNSCC cells were treated with p38 inhibitor and were subjected to increasing dosage of cisplatin. Western blot, immunohistochemistry and RT PCR analysis were performed to investigate expression level of p-p38 and Cancer stem cell (CSC) markers in cisplatin resistant HNSCC cells with or without p38 inhibitor. Chemoresistance, wound healing capacity and Spheroids formation capacity were assessed following p38 inhibition in cisplatin resistant HNSCC cell lines. In addition, alkaline comet assay and γ-H2AX immunostaining were performed to evaluate the DNA damage response and repair abilities in cisplatin resistant HNSCC cells after p38 inhibition.

RESULTS

It was observed that following p38 inhibition, cisplatin resistant HNSCC cells exhibited significant reduction in expression of CSC markers, β-catenin, reduced migration potential and sphere forming ability along with increased apoptotic index demonstrating there was increased sensitivity towards Cisplatin. Molecular docking study identified several interface amino acid residues between p-p38 with CSC markers (Klf4 and CD44). p38 inhibited cisplatin resistant HNSCC cells also exhibited increased DNA damage as measured by Comet assay and γ-H₂AX foci formation index. There was significant decrease in DNA repair as confirmed by reduced ERRC1 expression.

CONCLUSIONS

Our study demonstrated that p38 MAPK inhibition can be a targeted approach to overcome resistance in HNSCC thereby escalating the effectiveness of chemotherapy in HNSCC.

Reactive Pt(II) center as part of redox-active quinoline-based heterocyclic scaffolds toward new anticancer leads

New cisplatin analogs in which the diamminedichloro-Pt(II) unit is conjugated to dihydroquinoline- or tetrahydroquinoline frameworks were synthesized and subjected to biological evaluation in order to understand their effects on cellular redox homeostasis and cell viability. They exhibited better selectivity towards cancer cells (A549) compared to mice fibroblast NIH3T3 cells, with cytotoxicity in the same range as that of cisplatin. There was structure-dependent variation in the levels of ROS and were also able to induce cell death, as evidenced by accumulation of cells in sub-G1 phase.

A Role for Maternal Factors in Suppressing Cytoplasmic Incompatibility

Wolbachia are maternally transmitted bacterial endosymbionts, carried by approximately half of all insect species. Wolbachia prevalence in nature stems from manipulation of host reproduction to favor the success of infected females. The best known reproductive modification induced by Wolbachia is referred to as sperm-egg Cytoplasmic Incompatibility (CI). In CI, the sperm of Wolbachia-infected males cause embryonic lethality, attributed to paternal chromatin segregation defects during early mitotic divisions. Remarkably, the embryos of Wolbachia-infected females “rescue” CI lethality, yielding egg hatch rates equivalent to uninfected female crosses. Several models have been discussed as the basis for Rescue, and functional evidence indicates a major contribution by Wolbachia CI factors. A role for host contributions to Rescue remains largely untested. In this study, we used a chemical feeding approach to test for CI suppression capabilities by Drosophila simulans. We found that uninfected females exhibited significantly higher CI egg hatch rates in response to seven chemical treatments that affect DNA integrity, cell cycle control, and protein turnover. Three of these treatments suppressed CI induced by endogenous wRi Wolbachia, as well as an ectopic wMel Wolbachia infection. The results implicate DNA integrity as a focal aspect of CI suppression for different Wolbachia strains. The framework presented here, applied to diverse CI models, will further enrich our understanding of host reproductive manipulation by insect endosymbionts.

Preparation of CoS nanoparticles-cisplatin bio-conjugates and investigation of their effects on SH-SY5Y neuroblastoma cell line

Neuroblastoma is one of the most widely seen under the age of 15 tumors that occur in the adrenal medulla and sympathetic ganglia. Cisplatin, an antineoplastic drug, is a Platinum-based compound and is known to inhibit the proliferation of neuroblastoma cells. Effective applications of nanoparticles in biomedical areas such as biomolecular, antimicrobial detection and diagnosis, tissue engineering, theranostics, biomarking, drug delivery, and anti-cancer have been investigated in many studies. This study aims to prepare the bioconjugates of CoS (cobalt sulfide) nanoparticles (NPs) with cisplatin combination groups and to evaluate their effects on the neuroblastoma cell line. Nanoparticle synthesis was done using the green synthesis technique using Punica granatum plant extract. The size and shape of CoS NPs were characterized by SEM, FT-IR, and XRD. Zeta potential was confirmed by the DLS study. For this purpose, the SH-SY5Y neuroblastoma cell line was cultured in a suitable cell culture medium. Cisplatin 5 µg and different concentrations (Cisplatin + CoS NPs bioconjugates (5, 10, 25, 50, 75 μg) doses were applied to SH-SY5Y neuroblastoma cell lines for 24 h. TAC, TOS and MTT tests were performed 24 h after the application. According to the MTT test results, cisplatin and CoS NP combinations reduced the proliferation of neuroblastoma cells by 78 to 57% compared to the cisplatin control. From the findings obtained; the most effective Bio-conjugate group was Cisplatin 5 μg/mL + CoS 75 μg/mL.

Lactate dehydrogenase inhibition affects homologous recombination repair independently of cell metabolic asset; implications for anticancer treatment

BACKGROUND

Cancer cells show highly increased glucose utilization which, among other cancer-essential functions, was found to facilitate DNA repair. Lactate dehydrogenase (LDH) activity is pivotal for supporting the high glycolytic flux of cancer cells; to our knowledge, a direct contribution of this enzyme in the control of DNA integrity was never investigated. In this paper, we looked into a possible LDH-mediated regulation of homologous recombination (HR) repair.

METHODS

We identified two cancer cell lines with different assets in energy metabolism: either based on glycolytic ATP or on oxidative reactions. In cells with inhibited LDH, we assessed HR function by applying four different procedures.

RESULTS

Our findings revealed an LDH-mediated control of HR, which was observed independently of cell metabolic asset. Since HR inhibition is known to make cancer cells responsive to PARP inhibitors, in both the cellular models we finally explored the effects of a combined inhibition of LDH and PARP.

CONCLUSIONS

The obtained results suggest for LDH a central role in cancer cell biology, not merely linked to the control of energy metabolism. The involvement of LDH in the DNA damage response could suggest new drug combinations to obtain improved antineoplastic effects.

GENERAL SIGNIFICANCE

Several evidences have correlated the metabolic features of cancer cells with drug resistance and LDH inhibition has been repeatedly shown to increase the antineoplastic power of chemotherapeutics. By shedding light on the processes linking cell metabolism to the control of DNA integrity, our findings also give a mechanistic explanation to these data.

Overcoming Limitations of Cisplatin Therapy by Additional Treatment With the HSP90 Inhibitor Onalespib

Rational

Cisplatin based cancer therapy is an affordable and effective standard therapy for several solid cancers, including lung, ovarian and head and neck cancers. However, the clinical use of cisplatin is routinely limited by the development of drug resistance and subsequent therapeutic failure. Therefore, methods of circumventing cisplatin resistance have the potential to increase therapeutic efficiency and dramatically increase overall survival. Cisplatin resistance can be mediated by alterations to the DNA damage response, where multiple components of the repair machinery have been described to be client proteins of HSP90. In the present study, we have investigated whether therapy with the novel HSP90 inhibitor onalespib can potentiate the efficacy of cisplatin and potentially reverse cisplatin resistance in ovarian and head and neck cancer cells.

Methods

Cell viability, cancer cell proliferation and migration capacity were evaluated in vitro on models of ovarian and head and neck cancer cells. Western blotting was used to assess the downregulation of HSP90 client proteins and alterations in downstream signaling proteins after exposure to cisplatin and/or onalespib. Induction of apoptosis and DNA damage response were evaluated in both monotherapy and combination therapy groups.

Results

Results demonstrate that onalespib enhances the efficiency of cisplatin in a dose-dependent manner. Tumor cells treated with both drugs displayed lower viability and a decreased migration rate compared to vehicle-control cells and cells treated with individual compounds. An increase of DNA double strand breaks was observed in both cisplatin and onalespib treated cells. The damage was highest and most persistent in the combination group, delaying the DNA repair machinery. Further, the cisplatin and onalespib co-treated cells had greater apoptotic activity compared to controls.

Conclusion

The results of this study demonstrate that the reduced therapeutic efficacy of cisplatin due to drug-resistance could be overcome by combination treatment with onalespib. We speculate that the increased apoptotic signaling, DNA damage as well as the downregulation of HSP90 client proteins are important mechanisms promoting increased sensitivity to cisplatin treatment.

Impact of mutations in homologous recombination repair genes on treatment outcomes for metastatic castration resistant prostate cancer

INTRODUCTION

A significant proportion of patients with metastatic castration-resistant prostate cancer (mCRPC) harbor mutations in homologous recombination (HR) repair genes, with some of these mutations associating with increased tumor susceptibility to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum-based chemotherapy. While mutations in some HR repair genes (e.g., BRCA1/2) have been associated with a more aggressive clinical course, prior studies correlating HR mutational status with treatment response to androgen receptor (AR) signaling inhibitors (ARSIs) or taxane-based chemotherapy have yielded conflicting results.

METHODS

We conducted a single-center retrospective analysis to assess clinical outcomes to conventional, regulatory-approved therapies in mCRPC patients with somatic (monoallelic and biallelic) and/or germline HR repair mutations compared to patients without alterations as determined by clinical-grade next-generation sequencing assays. The primary endpoint was PSA30/PSA50 response, defined as ≥30%/≥50% prostate-specific antigen (PSA) reduction from baseline. Secondary endpoints of PSA progression-free survival (pPFS) and clinical/radiographic progression-free survival (crPFS) were estimated using Kaplan-Meier methods.

RESULTS

A total of 90 consecutively selected patients were included in this analysis, of which 33 (37%) were identified to have HR repair gene mutations. Age, race, Gleason score, prior surgery, and receipt of prior radiation therapy were comparable between carriers and non-carriers. There was no evidence that PSA30/PSA50 differed by HR gene mutational status. Median pPFS and crPFS ranged 3-14 months across treatment modalities, but there was no evidence either differed by HR gene mutational status (all p>0.05). There was also no difference in outcomes between those with BRCA2 or PALB2 mutations (n = 17) compared to those without HR repair mutations.

CONCLUSION

HR gene mutational status was associated with comparable clinical outcomes following treatment with ARSIs or taxane-based chemotherapy. Additional prospective studies are needed to confirm these findings.

The Anti-Tumor Effects of Oenothera odorata Extract Are Mediated by Inhibition of Glycolysis and Cellular Respiration in Cancer Cells

Cancer is caused by uncontrolled cell division and is a leading cause of mortality worldwide. Oenothera odorata (O. odorata) extract is used in herbal medicine to inhibit inflammation, but its potential anti-tumor properties have not been fully evaluated. Here, we demonstrated that O. odorata extract inhibits the proliferation of lung adenocarcinoma and melanoma cell lines In Vitro, and also inhibits the growth of melanoma cells In Vivo. After partitioning the extract with n-hexane, chloroform, ethyl acetate, and n-butanol, it was found that the butanol-soluble (OOB) and water-soluble (OOW) fractions of O. odorata extract are effective at inhibiting tumor cell growth In Vivo although OOW is more effective than OOB. Interestingly, these fractions did not inhibit the growth of non-cancerous cells. The anti-proliferative effects of the OOW fraction were found to be mediated by inhibition of glycolysis and cellular respiration. UPLC of both fractions showed two major common peaks, which were predicted to be hydrolyzable tannin-related compounds. Taken together, these data suggest that O. odorata extract has anti-tumor properties, and the molecular mechanism involves metabolic alterations and inhibition of cell proliferation. O. odorata extract therefore holds promise as a novel natural product for the treatment of cancer.

Isodeoxyelephantopin Inactivates Thioredoxin Reductase 1 and Activates ROS-Mediated JNK Signaling Pathway to Exacerbate Cisplatin Effectiveness in Human Colon Cancer Cells

Colon cancer is one of the leading causes of cancer-related death in the world. The development of new drugs and therapeutic strategies for patients with colon cancer are urgently needed. Isodeoxyelephantopin (ESI), a sesquiterpene lactone isolated from the medicinal plant Elephantopus scaber L., has been reported to exert antitumor effects on several cancer cells. However, the molecular mechanisms underlying the action of ESI is still elusive. In the present study, we found that ESI potently suppressed cell proliferation in human colon cancer cells. Furthermore, our results showed that ESI treatment markedly increased cellular reactive oxygen species (ROS) levels by inhibiting thioredoxin reductase 1 (TrxR1) activity, which leads to activation of the JNK signaling pathway and eventually cell death in HCT116 and RKO cells. Importantly, we found that ESI markedly enhanced cisplatin-induced cytotoxicity in HCT116 and RKO cells. Combination of ESI and cisplatin significantly increased the production of ROS, resulting in activation of the JNK signaling pathway in HCT116 and RKO cells. In vivo, we found that ESI combined with cisplatin significantly suppressed tumor growth in HCT116 xenograft models. Together, our study provide a preclinical proof-of-concept for ESI as a potential strategy for colon cancer treatment.

Brother of regulator of imprinted sites inhibits cisplatin-induced DNA damage in non-small cell lung cancer

Cisplatin (DDP) chemotherapy is the primary modality of treatment for non-small cell lung cancer (NSCLC). However, due to the occurrence of DDP resistance, only a limited number of patients benefit from this treatment regimen. Brother of Regulator of Imprinted Sites (BORIS) is expressed elevated in NSCLC. Whether BORIS is involved in the DDP resistance of NSCLC is currently undetermined. The association between BORIS expression and overall survival rate of 156 patients with NSCLC who received DDP chemotherapy was analyzed in the present study. In order to investigate the function of BORIS in DDP chemotherapy, BORIS was silenced or overexpressed in four NSCLC cell lines. The cell viabilities, apoptosis and DNA damage induced by DDP were evaluated in these cell lines. In addition, the regulations of DNA repair genes were assessed, including POLH, ERCC1, BRCA1, MSH6 and XPA. The present study demonstrated that high BORIS expression was associated with decreased overall survival rate in patients with NSCLC who received DDP chemotherapy. The patients who benefited and went into remission following DDP therapy expressed a relatively low level of BORIS, suggesting the potential function of BORIS in DDP resistance. Cell experiments revealed that NSCLC cells that had a higher proliferation rate and resisted DDP treatment expressed a relatively higher level of BORIS. Knockdown of BORIS in NSCLC cells induced DNA damage; inhibiting cell proliferation and sensitizing cells to DDP treatment. In contrast, BORIS overexpression suppressed DDP-induced DNA damage. Notably, the mismatch repair factor mutS homolog 6 (MSH6) was regulated by BORIS, indicating its association with BORIS-associated DDP resistance in NSCLC. The findings of the present study suggest that BORIS suppresses DNA damage and promotes the progression of NSCLC and DDP resistance. The present study indicates the potential application of BORIS in NSCLC therapy and prognosis.

Linagliptin, the dipeptidyl peptidase-4 enzyme inhibitor, lessens CHOP and GRP78 biomarkers levels in cisplatin-induced neurobehavioral deficits: A possible restorative gateway

Cisplatin (CP) is a cornerstone chemotherapeutic agent, however, its neurotoxicity is a chief cause of its limited usage. Linagliptin, which is a dipeptidyl peptidase-4 enzyme inhibitor, has exhibited considerable neuroprotective potential. We aimed to evaluate the linagliptin modulatory effects on endoplasmic reticulum (ER) stress, redox status, and apoptosis in CP-induced neurotoxicity. Thirty mice were allocated equally into the control group, Group II: CP group, and Group III: linagliptin treated CP group. All groups were subjected to the measurement of hippocampal messenger RNA gene expression of glucose-regulated protein-78 and C/EBP homologous protein (CHOP). Peroxisome proliferator-activated receptor γ coactivator 1α and cleaved caspase-3 levels were assessed by the enzyme-linked immunosorbent assay technique while malondialdehyde, reduced glutathione levels and superoxide dismutase activity were detected spectrophotometrically. Linagliptin ameliorated ER stress and enhanced antioxidant status with cognitive function improvement. Linagliptin may be considered a promising neuroprotective agent owing to its ability to reduce ER/oxidative stress.

Aconitase 2 sensitizes MCF-7 cells to cisplatin eliciting p53-mediated apoptosis in a ROS-dependent manner

Aconitase 2 (ACO2) belongs to the tricarboxylic acid (TCA) cycle, which represents a key metabolic hub for cellular metabolism that is frequently altered in cancer for satisfying bioenergetic and biosynthetic requirements of proliferating cells. The promotion of ACO2 activity in breast cancer cell lines was shown to slow down proliferation imposing a switch from aerobic glycolysis to oxidative metabolism. The alteration of metabolic pathways in cancer also impinges on the sensitivity to chemotherapeutic interventions. In this work, we evidence that the presence of ACO2 sensitizes cells to the treatment with the genotoxic agents cisplatin (CDDP) and doxorubicin activating the apoptotic cell death mechanism. This response was driven by the accumulation of reactive oxygen species (ROS) following both ACO2 overexpression and CDDP exposure that permit the stabilization/activation of p53 in nuclear and mitochondrial compartments. Collectively, our results highlight that in ACO2 overexpressing cells the promotion of mitochondrial metabolism accounts for increased ROS production that was buffered by p53 mitochondrial recruitment and autophagy induction. However, these systems are not able to counteract the CDDP-mediated oxidative stress that becomes the Achilles heel for increasing susceptibility to apoptotic cell death.

Kevetrin induces apoptosis in TP53 wild‑type and mutant acute myeloid leukemia cells

Tumor protein p53 is a key regulator of several cellular pathways, including DNA repair, cell cycle and angiogenesis. Kevetrin exhibits p53-dependent as well as-independent activity in solid tumors, while its effects on leukemic cells remain unknown. The aim of the present study was to analyze the response of acute myeloid leukemia (AML) cell lines (TP53 wild-type: OCI-AML3 and MOLM-13; and TP53-mutant: KASUMI-1 and NOMO-1) to kevetrin at a concentration range of 85–340 µM. The cellular and molecular effects of the treatment were analyzed in terms of cell growth, viability [Annexin V-propidium iodide (PI) staining] and cell cycle alterations (PI staining). Gene expression profiling, western blotting and immunofluorescence were performed to elucidate the pathways underlying kevetrin activity. Pulsed exposure exerted no effect on the wild-type cells, but was effective on mutant cells. After continuous treatment, significant cell growth arrest and apoptosis were observed in all cell lines, with TP53-mutant models displaying a higher sensitivity and p53 induction. Kevetrin also displayed efficacy against TP53 wild-type and mutant primary AML, with a preferential cytotoxic activity against blast cells. Gene expression profiling revealed a common core transcriptional program altered by drug exposure and the downregulation of glycolysis, DNA repair and unfolded protein response signatures. These findings suggest that kevetrin may be a promising therapeutic option for patients with both wild-type and TP53-mutant AML.

Ascorbate sensitizes human osteosarcoma cells to the cytostatic effects of cisplatin

Osteosarcoma (OS) is the most common malignant bone tumor and a leading cause of cancer-related deaths in children and adolescents. Current standard treatments for OS are a combination of preoperative chemotherapy, surgical resection, and adjuvant chemotherapy. Cisplatin is used as the standard chemotherapeutic for OS treatment, but it induces various adverse effects, limiting its clinical application. Improving treatment efficacy without increasing the cisplatin dosage is desirable. In the present study, we assessed the combined effect of ascorbate on cisplatin treatment using cultured human OS cells. Co-treatment with ascorbate induced greater suppression of OS cell but not nonmalignant cell proliferation. The chemosensitizing effect of ascorbate on cisplatin treatment was tightly linked to ROS production. Altered cellular redox state due to increased ROS production modified glycolysis and mitochondrial function in OS cells. In addition, OS cell sphere formation was markedly decreased, suggesting that ascorbate increased the treatment efficacy of cisplatin against stem-like cells in the cancer cell population. We also found that enhanced MYC signaling, ribosomal biogenesis, glycolysis, and mitochondrial respiration are key signatures in OS cells with cisplatin resistance. Furthermore, cisplatin resistance was reversed by ascorbate. Taken together, our findings provide a rationale for combining cisplatin with ascorbate in therapeutic strategies against OS.

Astragaloside IV sensitizes non-small cell lung cancer cells to cisplatin by suppressing endoplasmic reticulum stress and autophagy

Background

Cisplatin is an effective chemotherapeutic drug for treating various cancers including non-small cell lung cancer (NSCLC), but resistance to cisplatin remains the main limitation to its use in clinic. Astragaloside IV (AS-IV), which is derived from Astragalus membranaceus, has been proven to participate in various anti-cancer activities including anti-cancer, anti-oxidative, and anti-inflammatory functions.

Method

In this study, we explored the role of AS-IV in cisplatin chemoresistance to NSCLC cells by establishing cisplatin-resistant the NSCLC cell lines, A549^Cis and H1299^Cis.

Results

Cisplatin inhibited viability and promoted apoptosis of A549^Cis and H1299^Cis cells in a dose-dependent manner. In addition, cisplatin upregulated the levels of autophagy-related proteins (Beclin1, LC3 II/I) and endoplasmic reticulum (ER) stress-related proteins (glucose regulated protein 78: GRP78, protein kinase R (PKR)-like endoplasmic reticulum kinase: PERK), indicating that cisplatin caused autophagy and ER stress in NSCLC cells. However, treatment combined with AS-IV dose-dependently suppressed cell viability and increased the cell apoptosis rate in A549^Cis and H1299^Cis cells, suggesting that AS-IV elevated the anti-tumor role of cisplatin in NSCLC cells. AS-IV treatment suppressed the expression of GRP78 and Beclin1. Inhibition of ER stress or autophagy both counteracted the inhibitory effect of AS-IV on chemoresistance to cisplatin in NSCLC cells.

Conclusions

AS-IV sensitized NSCLC cells to cisplatin through suppressing ER stress and autophagy. This study provides a novel strategy of cisplatin combined with AS-IV for the treatment of cisplatin-resistant NSCLC patients.

Is GSH Chelated Pt Molecule Inactive in Anti-Cancer Treatment? A Case Study of Pt6 GS4

Platinum (Pt) drugs are widely used in anti-cancer treatment although many reports advocated that tumor cells could inactivate Pt drugs via glutathione-Pt (GSH-Pt) adducts formation. To date, GSH chelated Pt molecules have not been assessed in cancer treatment because GSH-Pt adducts are not capable of killing cancer cells, which is widely accepted and well followed. In this report, endogenous biothiol is utilized to precisely synthesize a GSH chelated Pt molecule (Pt₆ GS₄ ). This Pt₆ GS₄ molecule can be well taken up by aggressive triple negative breast cancer (TNBC) cells. Subsequently, its metabolites could enter nuclei to interact with DNA, finally the DNA-Pt complex triggers TNBC cell apoptosis via the p53 pathway. Impressively, high efficacy for anti-cancer treatment is achieved by Pt₆ GS₄ both in vitro and in vivo when compared with traditional first-line carboplatin in the same dosage. Compared with carboplatin, Pt₆ GS₄ keeps tumor bearing mice alive for a longer time and is non-toxic for the liver and kidneys. This work opens a route to explore polynuclear Pt compound with accurate architecture for enhancing therapeutic effects and reducing systemic toxicity.

Natural Function and Structural Modification of Climacostol, a Ciliate Secondary Metabolite

The review highlights the main results of two decades of research on climacostol (5-[(2Z)-non-2-en-1-yl]benzene-1,3-diol), the resorcinolic lipid produced and used by the ciliated protozoan Climacostomum virens for chemical defense against a wide range of predators, and to assist its carnivorous feeding. After the first studies on the physiological function of climacostol, the compound and some analogues were chemically synthesized, thus allowing us to explore both its effect on different prokaryotic and eukaryotic biological systems, and the role of its relevant structural traits. In particular, the results obtained in the last 10 years indicate climacostol is an effective antimicrobial and anticancer agent, bringing new clues to the attempt to design and synthesize additional novel analogues that can increase or optimize its pharmacological properties.

Pituranthos chloranthus Oil as an Antioxidant-Based Adjuvant Therapy against Cisplatin-Induced Nephrotoxicity

The therapeutic outcome of cisplatin is limited due to its adverse side effects in normal tissues. Despite its potent antineoplastic effect, cisplatin is known by a relevant collateral action, for instance, acute renal failure. The aim of this study was to assess the effectiveness of Pituranthos chloranthus (PC) essential oil for contracting cisplatin-induced toxicity, in Balb/c mice. The standard mouse model of cisplatin-induced acute kidney injury (AKI), consisting of one intraperitoneal injection of cisplatin (20 mg/kg), was adopted. Mice were pretreated by intraperitoneal administration of PC (5 and 10 mg/Kg b.w) for one week. Cisplatin induced alteration in renal and liver functions, evidenced by increased serum biomarkers levels (creatinine, ALT, and AST). Significant mitigation of cisplatin-induced toxicity was confirmed by lowered levels of serum biomarkers and reduced DNA damage in liver and kidney. PC also restored the alterations in oxidative stress markers and proinflammatory cytokine IFN-γ level. Overall, this study provides, for the first time, that PC can be applied as an antioxidant-adjuvant treatment to mitigate cisplatin-induced renal failure.

Prediction of Nephrotoxicity Associated With Cisplatin-Based Chemotherapy in Testicular Cancer Patients

Background

Cisplatin-based chemotherapy may induce nephrotoxicity. This study presents a random forest predictive model that identifies testicular cancer patients at risk of nephrotoxicity before treatment.

Methods

Clinical data and DNA from saliva samples were collected for 433 patients. These were genotyped on Illumina HumanOmniExpressExome-8 v1.2 (964 193 markers). Clinical and genomics-based random forest models generated a risk score for each individual to develop nephrotoxicity defined as a 20% drop in isotopic glomerular filtration rate during chemotherapy. The area under the receiver operating characteristic curve was the primary measure to evaluate models. Sensitivity, specificity, and positive and negative predictive values were used to discuss model clinical utility.

Results

Of 433 patients assessed in this study, 26.8% developed nephrotoxicity after bleomycin-etoposide-cisplatin treatment. Genomic markers found to be associated with nephrotoxicity were located at NAT1, NAT2, and the intergenic region of CNTN6 and CNTN4. These, in addition to previously associated markers located at ERCC1, ERCC2, and SLC22A2, were found to improve predictions in a clinical feature–trained random forest model. Using only clinical data for training the model, an area under the receiver operating characteristic curve of 0.635 (95% confidence interval [CI] = 0.629 to 0.640) was obtained. Retraining the classifier by adding genomics markers increased performance to 0.731 (95% CI = 0.726 to 0.736) and 0.692 (95% CI = 0.688 to 0.696) on the holdout set.

Conclusions

A clinical and genomics-based machine learning algorithm improved the ability to identify patients at risk of nephrotoxicity compared with using clinical variables alone. Novel genetics associations with cisplatin-induced nephrotoxicity were found for NAT1, NAT2, CNTN6, and CNTN4 that require replication in larger studies before application to clinical practice.

Evaluating the immunoproteasome as a potential therapeutic target in cisplatin-resistant small cell and non-small cell lung cancer

PURPOSE

We evaluated the expression of proteasome subunits to assess whether the proteasome could be a therapeutic target in cisplatin-resistant lung cancer cells.

METHODS

Cisplatin-resistant (CR) variants were established from three non-small cell lung cancer (NSCLC) cell lines (A549, H1299, and H1975) and two small cell lung cancer (SCLC) cell lines (SBC3 and SBC5). The expression of proteasome subunits, the sensitivity to immunoproteasome inhibitors, and 20S proteasomal proteolytic activity were examined in the CR variants of the lung cancer cell lines.

RESULTS

All five CR cell lines highly expressed one or both of the immunoproteasome subunit genes, PSMB8 and PSMB9, while no clear trend was observed in the expression of constitutive proteasome subunits. The CR cells expressed significantly higher levels of PSMB8 and PSMB9 proteins, as well. The CR variants of the H1299 and SBC3 cell lines were more sensitive to immunoproteasome inhibitors, and had significantly more proteasomal proteolytic activity than their parental counterparts.

CONCLUSIONS

The immunoproteasome may be an effective therapeutic target in a subset of CR lung cancers. Proteasomal proteolytic activity may be a predictive marker for the efficacy of immunoproteasome inhibitors in cisplatin-resistant SCLC and NSCLC.

Kaempferol ameliorates Cisplatin induced nephrotoxicity by modulating oxidative stress, inflammation and apoptosis via ERK and NF-κB pathways

Anticancer drug like Cisplatin are associated with serious problem like nephrotoxicity. The effect of Kaempferol is a plant-derived flavonoid compound. The present work evaluated the effect of Kaempferol in mouse model of Cisplatin mediated nephrotoxicity also the involved mechanism. Oxidative stress, kidney function, histology, inflammation, apoptosis, level of proteins, Nrf2 translocation and its effect on cascades such as NF-κB and ERK were studied. It was observed that the pre-treatment of KPF reduced the Cisplatin mediated oxidative stress, inflammation, apoptosis and ameliorated renal injury and its functioning. Kaempferol suppressed the Cisplatin induced infiltration of mononuclear cells, levels of TNF-α, iNOS, IL-12, activation of NF-κB, phosphorylation of IκBα and nuclear translocation of p65 in renal tissues. Also KPF attenuated Cisplatin mediated phosphorylation of p38, ERK1/2 and JNK in renal tissues. KPF also corrected the levels of renal antioxidants and elevated the nuclear levels of HO-1 and Nrf2 in renal tissues. KPF attenuated the Cisplatin mediated apoptosis via down-regulating the levels of TP53, Bax/Bcl2 imbalance, activating caspase-3/9 and PARP. The outcomes conclude that KPF ameliorates Cisplatin-mediated nephrotoxicity by modulating oxidative stress, inflammation and apoptosis via ERK and NF-κB pathway.

Anticancer Activities of the Quinone-Methide Triterpenes Maytenin and 22-β-hydroxymaytenin Obtained from Cultivated Maytenus ilicifolia Roots Associated with Down-Regulation of miRNA-27a and miR-20a/miR-17-5p

Natural triterpenes exhibit a wide range of biological activities. Since this group of secondary metabolites is structurally diverse, effects may vary due to distinct biochemical interactions within biological systems. In this work, we investigated the anticancer-related activities of the quinone-methide triterpene maytenin and its derivative compound 22-β-hydroxymaytenin, obtained from Maytenus ilicifolia roots cultivated in vitro. Their antiproliferative and pro-apoptotic activities were evaluated in monolayer and three-dimensional cultures of immortalized cell lines. Additionally, we investigated the toxicity of maytenin in SCID mice harboring tumors derived from a squamous cell carcinoma cell line. Both isolated molecules presented pronounced pro-apoptotic activities in four cell lines derived from head and neck squamous cell carcinomas, including a metastasis-derived cell line. The molecules also induced reactive oxygen species (ROS) and down-regulated microRNA-27a and microRNA-20a/miR-17-5p, corroborating with the literature data for triterpenoids. Intraperitoneal administration of maytenin to tumor-bearing mice did not lead to pronounced histopathological changes in kidney tissue, suggesting low nephrotoxicity. The wide-ranging activity of maytenin and 22-β-hydroxymaytenin in head and neck cancer cells indicates that these molecules should be further explored in plant biochemistry and biotechnology for therapeutic applications.

Investigation of Bladder Cancer Cell Response to Cryoablation and Adjunctive Cisplatin Based Cryo/Chemotherapy

Due to a rising annual incidence of bladder cancer, there is a growing need for development of new strategies for treatment. In 2018, the World Cancer Research Fund and other groups reported that there were ~550,000 new cases worldwide of bladder cancer. It has been further estimated that >200,000 individuals die annually from bladder cancer worldwide. Various treatment options exist. However, many if not all remain suboptimal. While the preferred chemotherapeutic options have changed in the past few years there have been few advances in the bladder cancer medical device field. Cryoablation is now being evaluated as a new option for the treatment of bladder cancer. While several studies have shown cryoablation to be promising for the treatment of bladder cancer, a lack of basic information pertaining to dosing (minimal lethal temperature) necessary to destroy bladder cancer has limited its use as a primary therapeutic option. Concerns with bladder wall perforation and other side effects have also slowed adoption.

In an effort to detail the effects of freezing on bladder cancer, two human bladder cancer cell lines, SCaBER and UMUC3, were evaluated in vitro. SCaBER, a basal subtype of muscle invasive bladder cancer, and UMUC3, an intermediate transitional cell carcinoma, are both difficult to treat but are reportedly responsive to most conventional treatments. SCaBER and UMUC3 cells were exposed to a range of freezing temperatures from −10 to −25°C and compared to non-frozen controls. The data show that a single 5 minute freeze to −10°C did not affect cell viability, whereas −15°C and −20°C results in a significant reduction in viability 1 day post freeze to <20%. These populations, however, were able to recover in culture. A complete loss of cell viability was found following a single freeze at −25°C. Application of a repeat (double) freeze resulted in complete cell death at −20°C. In addition to freezing alone, studies investigating the impact of adjunctive low dose (1 μM) cisplatin pre-treatment (30 minutes and 24 hours) in combination with freezing were conducted. The combination of 30 minute cisplatin pre-treatment and mild (−15°C) freezing resulted in complete cell death. This suggests that subclinical doses of cisplatin may be synergistically effective when combined with freezing.

In summary, these in vitro results suggest that freezing to temperatures in the range of −20 to 25°C results in a high degree of bladder cancer cell destruction. Further, the data describe a potential combinatorial chemo/cryo therapeutic strategy for the treatment of bladder cancer.

The expression of copper transporters associated with the ototoxicity induced by platinum-based chemotherapeutic agents

BACKGROUND

Antitumor agents based on platinum have gained a well-established place in the treatment of several forms of cancer. Their efficiency is hampered by serious toxic effects against healthy tissues as well. Ototoxicity is a serious side effect leading to hearing impairment and represents an important issue affecting the patients' quality of life. The currently used platinum chemotherapeutics exert different toxicity towards cochlear cells. The aim of our study was to answer some questions regarding the differential uptake and cellular pharmacodynamics of Cisplatin (CDDP), Carboplatin (CBDCA) and Oxaliplatin (L-OHP) in the HEI-OC1 cochlear cell line.

METHODS

We studied the expression of copper transporters CTR1, ATP7A and ATP7B which are presumably involved in the uptake, cellular transport and efflux of platinum compounds by immunofluorescence microscopy and flow-cytometry. The cellular uptake of the compounds was evaluated through the determination of intracellular platinum concentration by atomic absorption spectroscopy. The effects of the treatment of HEI-OC1 cells with platinum compounds were also evaluated: cytotoxicity with the Cell Titer Blue viability test, formation of reactive oxygen species with 2',7' -dichlorofluorescein diacetate, genotoxicity with the comet assay and apoptosis with the cleaved PARP ELISA test.

RESULTS

CTR1, ATP7A and ATP7B were all expressed by HEI-OC1 cells. The treatment with the platinum compounds led to a modulation of their expression, manifested in a differential platinum uptake. Treatment with Cisplatin led to the highest intracellular concentration of platinum compared to Oxaliplatin and Carboplatin at the same dose. Treatment with CuSO4 reduced platinum uptake of all the compounds, significantly in the case of Cisplatin and Carboplatin. CDDP was the most cytotoxic against HEI-OC1 cells, with an IC50 = 65.79  μM, compared to 611.7 μM for L-OHP and 882.9 μM for CBDCA, at the same molar concentration. The production of ROS was the most intense after CDDP, followed by L-OHP and CBDCA. In the comet assay, at the 100 μM concentration, L-OHP and CBDCA induced DNA adducts while CDDP induced adducts as well as DNA strand breaks. CBDCA and L-OHP lead to a significant increase of cleaved PARP at 24h (p < 0.001), suggesting an important apoptotic process induced by these compounds at the used concentrations.

CONCLUSIONS

The results obtained in the current study suggest that the modulation of copper transporters locally may represent a new strategy against platinum drugs ototoxicity.