Cellular responses to Cisplatin-induced DNA damage

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.

Targeted Inhibition of miR-221/222 Promotes Cell Sensitivity to Cisplatin in Triple-Negative Breast Cancer MDA-MB-231 Cells

Cisplatin has been widely used in the treatment of a various types of cancers including triple-negative breast cancer (TNBC) by damaging DNA and inducing apoptosis. However, its anti-cancer effects are often limited due to chemo-resistance, which is one of the main reasons causing cancer relapse and metastasis. To overcome resistance, cisplatin is often used in combination with other drugs or molecules. Our study found that the targeted inhibition of miR-221/222 in MDA-MB-231 cells promoted cisplatin-induced cell apoptosis, and increased the cell sensitivity to cisplatin in vitro. Much higher expression levels of miR-221/222 were detected in the cisplatin-resistant MDA-MB-231 cells and in cisplatin-resistant breast cancer patients. The combination chemotherapy of cisplatin with anti-miR-221/222 showed much higher efficiency in suppressing tumor growth in the mice transplanted with MDA-MB-231 cells. In addition, anti-miR-221 and anti-miR-222 showed synergetic effects on improving sensitivity to cisplatin in MDA-MB-231 cells. Suppression of SOCS1-STAT3-Bcl-2 pathway and activation of p53-Pten signaling both contribute to anti-miR-221/222-induced sensitivity to cisplatin in MDA-MB-231 cells. These findings suggest the potential of a novel approach for the combination chemotherapy of cisplatin with small non-coding RNA in treatment of human TNBC.

Myricetin Abrogates Cisplatin-Induced Oxidative Stress, Inflammatory Response, and Goblet Cell Disintegration in Colon of Wistar Rats

Cisplatin [cis-diamminedichloroplatinum II] is an extensively prescribed drug in cancer chemotherapy; it is also useful for the treatment of diverse types of malignancies. Conversely, cisplatin is associated with a range of side effects such as nephrotoxicity, hepatotoxicity, gastrointestinal toxicity, and so on. Myricetin (3,5,7-trihydroxy-2-(3,4,5-trihydroxyphenyl)-4chromenone) is a very common natural flavonoid found in fruits, tea, and plants. It has been found to have high-value pharmacological properties and strong health benefits. To examine the role of myricetin in colon toxicity induced by cisplatin, we conducted a concurrent prophylactic study in experimental animals that were treated orally with myricetin for 14 days at two doses—25 and 50 mg/kg of body weight. On the 14th day, a single intraperitoneal injection of cisplatin (7.5 mg/kg body weight) was administered in all groups except control. The effects of myricetin in cisplatin-induced toxicity in the colon were assessed in terms of antioxidant status, phase-II detoxification enzymes, the level of inflammatory markers, and goblet cell disintegration. Myricetin was found to restore the level of all the antioxidant enzymes analyzed in the study. In addition, the compound ameliorated cisplatin-induced lipid peroxidation, increase in xanthine oxidase activity, and phase-II detoxifying enzyme activity. Myricetin also attenuated deteriorative effects induced by cisplatin by regulating the level of molecular markers of inflammation (NF-κB, Nrf-2, IL-6, and TNF-α), restoring Nrf-2 levels, and controlling goblet cell disintegration. The current study reinforces the conclusion that myricetin exerts protection in colon toxicity via up-regulation of inflammatory markers, improving anti-oxidant status, and protecting tissue damage.

Maresin 1 Mitigates Sepsis-Associated Acute Kidney Injury in Mice via Inhibition of the NF-κB/STAT3/MAPK Pathways

Acute kidney injury (AKI) is one of the most common and serious complications of sepsis in which the inflammatory cascade plays a crucial role. There is now increasing evidence that lipid mediators derived from the omega-3 fatty acid docosahexaenoic acid (DHA) have potent anti-inflammatory effects that promote the timely regression of acute inflammation. In this study, we investigated the protective effects and molecular mechanism of a novel DHA-derived lipid mediator Maresin 1 (MaR1) on AKI in septic mice. The cecal ligation and puncture (CLP) was used to establish a sepsis mice model. As a result, we found that MaR1 significantly increased the 7-day survival rate of septic mice and the anti-inflammatory factor IL-10 while reducing bacterial load and pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β). In addition, MaR1 dose dependently reduced renal injury scores and serum creatinine and urea nitrogen levels in septic mice while inhibiting renal neutrophil infiltration and myeloperoxidase (MPO) activity. In terms of signaling pathway, we found that MaR1 inhibits the expression of phosphorylated p65, Stat3, JNK, ERK, and p38 and significantly reduces nuclear translocation of p65. In conclusion, our results indicate that MaR1 is able to reduce neutrophil infiltration and inhibit nuclear factor-kappa B/signal transducer and activator of transcriptor 3/mitogen-activated protein kinase (NF-κB/STAT3/MAPK) activity and regulate inflammatory cytokine level to inhibit inflammatory response and thereby weaken sepsis-associated AKI in mice.

FEN1 inhibitor increases sensitivity of radiotherapy in cervical cancer cells

Background

Cervical cancer is one of the most common causes of cancer‐associated mortality among affected women in the world. At present, treatment with weekly cisplatin plus ionizing radiation (IR) therapy is the standard regimen for cervical cancer, especially for locally advanced cervical cancer. The purpose of this study is to determine whether FEN1 inhibitors could enhance the therapeutic effect of IR therapy.

Methods

Western blot was applied to determine the expression of FEN1‐ and apoptosis‐related proteins. Cell growth inhibition assay and colony formation assay were used to determine the effects of FEN1 inhibitor and IR exposure for Hela cells in vitro. CRISPR technology was used to knockdown FEN1 expression level of 293T cells, and tumor xenograft in nude mice was employed to determine the effects of FEN1 inhibitor and IR exposure on tumor growth in vivo.

Results

Our data revealed that FEN1 is overexpressed in HeLa cell and can be upregulated further by IR. We also demonstrated that FEN1 inhibitor enhances IR sensitivity of cervical cancer in vitro and in vivo.

Conclusion

FEN1 inhibitor SC13 could sensitize radiotherapy of cervical cancer cell.

Modulation of Calretinin Expression in Human Mesothelioma Cells Reveals the Implication of the FAK and Wnt Signaling Pathways in Conferring Chemoresistance towards Cisplatin

Malignant mesothelioma (MM) is an aggressive asbestos-linked neoplasm, characterized by dysregulation of signaling pathways. Due to intrinsic or acquired chemoresistance, MM treatment options remain limited. Calretinin is a Ca²⁺-binding protein expressed during MM tumorigenesis that activates the FAK signaling pathway, promoting invasion and epithelial-to-mesenchymal transition. Constitutive calretinin downregulation decreases MM cells’ growth and survival, and impairs tumor formation in vivo. In order to evaluate early molecular events occurring during calretinin downregulation, we generated a tightly controlled IPTG-inducible expression system to modulate calretinin levels in vitro. Calretinin downregulation significantly reduced viability and proliferation of MM cells, attenuated FAK signaling and reduced the invasive phenotype of surviving cells. Importantly, surviving cells showed a higher resistance to cisplatin due to increased Wnt signaling. This resistance was abrogated by the Wnt signaling pathway inhibitor 3289-8625. In various MM cell lines and regardless of calretinin expression levels, blocking of FAK signaling activated the Wnt signaling pathway and vice versa. Thus, blocking both pathways had the strongest impact on MM cell proliferation and survival. Chemoresistance mechanisms in MM cells have resulted in a failure of single-agent therapies. Targeting of multiple components of key signaling pathways, including Wnt signaling, might be the future method-of-choice to treat MM.

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

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

New Insights in the Pathogenesis of Cisplatin-Induced Nephrotoxicity

Cisplatin (cis-diamminedichloroplatinum II) is a widely used chemotherapeutic agent. However, efficacy and clinical utility of this drug is significantly limited by severe side effects such as nephrotoxicity which develops due to renal accumulation and bio-transformation in proximal tubular epithelial cells. Cisplatin-induced nephrotoxicity can be manifested as acute kidney injury (AKI), or as different types of tubulopathies, salt wasting, loss of urinary concentrating ability, and magnesium wasting. The attenuation of cisplatin-caused AKI is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis. However, mannitol treatment causes over-diuresis and consequent dehydration, indicating an urgent need for the clinical use of newly designed, safe and efficacious renoprotective drug, as an additive therapy for high dose cisplatin-treated patients. Accordingly, we emphasized current knowledge regarding molecular mechanisms responsible for cisplatin-caused nephrotoxicity and we described in detail the main clinical manifestations of cisplatin-induced renal dysfunction in order to pave the way for the design of new therapeutic approaches that can minimize detrimental effects of cisplatin in the kidneys. Having in mind that most of cisplatin-induced cytotoxic effects against renal cells are, at the same time, involved in anti-tumor activity of cisplatin, new nephroprotective therapeutic strategies have to prevent renal injury and inflammation without affecting cisplatin-induced toxicity against malignant cells.

Discovery of Inhibitors for Proliferating Cell Nuclear Antigen Using a Computational-Based Linked-Multiple-Fragment Screen

Proliferating cell nuclear antigen (PCNA) is a central factor in DNA replication and repair pathways that plays an essential role in genome stability. The functional roles of PCNA are mediated through an extensive list of protein-protein interactions, each of which transmits specific information in protein assemblies. The flexibility at the PCNA-protein interaction interfaces offers opportunities for the discovery of functionally selective inhibitors of DNA repair pathways. Current fragment-based drug design methodologies can be limited by the flexibility of protein interfaces. These factors motivated an approach to defining compounds that could leverage previously identified subpockets on PCNA that are suitable for fragment-binding sites. Methodologies for screening multiple connected fragment-binding events in distinct subpockets are deployed to improve the selection of fragment combinations. A flexible backbone based on N-alkyl-glycine amides offers a scaffold to combinatorically link multiple fragments for in silico screening libraries that explore the diversity of subpockets at protein interfaces. This approach was applied to discover new potential inhibitors of DNA replication and repair that target PCNA in a multiprotein recognition site. The screens of the libraries were designed to computationally filter ligands based upon the fragments and positions to <1%, which were synthesized and tested for direct binding to PCNA. Molecular dynamics simulations also revealed distinct features of these novel molecules that block key PCNA-protein interactions. Furthermore, a Bayesian classifier predicted 15 of the 16 new inhibitors to be modulators of protein-protein interactions, demonstrating the method's utility as an effective screening filter. The cellular activities of example ligands with similar affinity for PCNA demonstrate unique properties for novel selective synergy with therapeutic DNA-damaging agents in drug-resistant contexts.

DNA Damage and Associated DNA Repair Defects in Disease and Premature Aging

Genetic information is constantly being attacked by intrinsic and extrinsic damaging agents, such as reactive oxygen species, atmospheric radiation, environmental chemicals, and chemotherapeutics. If DNA modifications persist, they can adversely affect the polymerization of DNA or RNA, leading to replication fork collapse or transcription arrest, or can serve as mutagenic templates during nucleic acid synthesis reactions. To combat the deleterious consequences of DNA damage, organisms have developed complex repair networks that remove chemical modifications or aberrant base arrangements and restore the genome to its original state. Not surprisingly, inherited or sporadic defects in DNA repair mechanisms can give rise to cellular outcomes that underlie disease and aging, such as transformation, apoptosis, and senescence. In the review here, we discuss several genetic disorders linked to DNA repair defects, attempting to draw correlations between the nature of the accumulating DNA damage and the pathological endpoints, namely cancer, neurological disease, and premature aging.

Protective effects of zingerone on cisplatin-induced nephrotoxicity in female rats

Zingerone (ZO), one of the active components of ginger (Zingiber officinale), is a phenolic alkanone with antioxidant, antiapoptotic, and anti-inflammatory properties. Cisplatin (CP) is a widely used chemotherapeutic drug for solid tumors, but its therapeutic use is limited due to dose-dependent nephrotoxicity. In the present study, we investigated the ameliorative effect of ZO against CP-induced nephrotoxicity. Intraperitoneal administration of single-dose CP (7 mg/kg body weight) on the first day enhanced kidney lipid peroxidation and reduced antioxidant enzyme activities such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione (GSH). CP increased serum urea and creatinine levels and disrupted histological integrity while causing a decrease aquaporin 1 (AQP1) level in the kidney tissues. CP induced inflammatory responses by elevating the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-33 (IL-33) and nuclear factor kappa B (NF-κB), and activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, it also caused oxidative DNA damage and activation of apoptotic pathway by increasing of 8-hydroxy-2'-deoxyguanosine (8-OHdG), p53, cysteine aspartate-specific protease-3 (caspase-3), and Bcl-2-associated x protein (bax) while decreasing B cell lymphoma-2 (Bcl-2). However, treatment with ZO at a dose of 25 and 50 mg/kg b.wt. for 7 days significantly decreased oxidative stress, apoptosis, inflammation, and histopathological alterations while increased AQP1 levels in the kidney tissue. The results of the current study suggested that ZO as an effective natural product attenuates CP-induced nephrotoxicity.

Expression Signatures of Cisplatin- and Trametinib-Treated Early-Stage Medaka Melanomas

Small aquarium fish models provide useful systems not only for a better understanding of the molecular basis of many human diseases, but also for first-line screening to identify new drug candidates. For testing new chemical substances, current strategies mostly rely on easy to perform and efficient embryonic screens. Cancer, however, is a disease that develops mainly during juvenile and adult stage. Long-term treatment and the challenge to monitor changes in tumor phenotype make testing of large chemical libraries in juvenile and adult animals cost prohibitive. We hypothesized that changes in the gene expression profile should occur early during anti-tumor treatment, and the disease-associated transcriptional change should provide a reliable readout that can be utilized to evaluate drug-induced effects. For the current study, we used a previously established medaka melanoma model. As proof of principle, we showed that exposure of melanoma developing fish to the drugs cisplatin or trametinib, known cancer therapies, for a period of seven days is sufficient to detect treatment-induced changes in gene expression. By examining whole body transcriptome responses we provide a novel route toward gene panels that recapitulate anti-tumor outcomes thus allowing a screening of thousands of drugs using a whole-body vertebrate model. Our results suggest that using disease-associated transcriptional change to screen therapeutic molecules in small fish model is viable and may be applied to pre-clinical research and development stages in new drug discovery.

Trifluoperazine, an Antipsychotic Drug, Effectively Reduces Drug Resistance in Cisplatin-Resistant Urothelial Carcinoma Cells via Suppressing Bcl-xL: An In Vitro and In Vivo Study

Cisplatin-based chemotherapy is the primary treatment for metastatic bladder urothelial carcinoma (UC). Most patients inevitably encounter drug resistance and resultant disease relapse. Reduced apoptosis plays a critical role in chemoresistance. Trifluoperazine (TFP), an antipsychotic agent, has demonstrated antitumor effects on various cancers. This study investigated the efficacy of TFP in inhibiting cisplatin-resistant bladder UC and explored the underlying mechanism. Our results revealed that cisplatin-resistant UC cells (T24/R) upregulated the antiapoptotic factor, B-cell lymphoma-extra large (Bcl-xL). Knockdown of Bcl-xL by siRNA resensitized cisplatin-resistant cells to the cisplatin cytotoxic effect. TFP (10–45 μM) alone elicited dose-dependent cytotoxicity, apoptosis, and G0/G1 arrest on T24/R cells. Co-treatment of TFP potentiated cisplatin-induced cytotoxicity in T24/R cells. The phenomenon that TFP alleviated cisplatin resistance to T24/R was accompanied with concurrent suppression of Bcl-xL. In vivo models confirmed that TFP alone effectively suppressed the T24/R xenograft in nude mice. TFP co-treatment enhanced the antitumor effect of cisplatin on the T24/R xenograft. Our results demonstrated that TFP effectively inhibited cisplatin-resistant UCs and circumvented cisplatin resistance with concurrent Bcl-xL downregulation. These findings provide a promising insight to develop a therapeutic strategy for chemoresistant UCs.

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

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

Curcumin enhances cisplatin sensitivity by suppressing NADPH oxidase 5 expression in human epithelial cancer

Cisplatin-based chemotherapy regimens serve a pivotal role in human cancer treatment. Nevertheless, treatment failure may occur if the cancer is inherently resistant to cisplatin or acquires a resistant phenotype during the course of treatment. Although cisplatin resistance can hinder the efficacy of cisplatin treatment for human cancer, the underlying mechanism remains poorly understood. The current study established a cisplatin-resistant human epithelial cancer cell line. Notably, differential upregulation of NADPH oxidase 5 (NOX5) was identified in this resistant cell line. Furthermore, cisplatin treatment induced cancer cells to express NOX5 and cells that overexpressed NOX5 exhibited greater resistance to cisplatin via the activation of Akt. Treatment with curcumin may suppress NOX5 expression in cancer cells and enhance sensitivity to cisplatin treatment. In a xenograft model, a combined regimen of cisplatin with low-dose curcumin significantly reduced malignant tumor growth. These data demonstrate that curcumin has a chemosensitizing effect on cisplatin-resistant epithelial cancer types. Therefore, the use of curcumin in addition to a cisplatin-based treatment regimen may improve treatment outcomes in human patients with epithelial cancer.

ATR mediates cisplatin resistance in 3D-cultured breast cancer cells via translesion DNA synthesis modulation

Tissue architecture and cell–extracellular matrix (cell–ECM) interaction determine the organ specificity; however, the influences of these factors on anticancer drugs preclinical studies are highly neglected. For considering such aspects, three-dimensional (3D) cell culture models are relevant tools for accurate analysis of cellular responses to chemotherapy. Here we compared the MCF-7 breast cancer cells responses to cisplatin in traditional two-dimensional (2D) and in 3D-reconstituted basement membrane (3D-rBM) cell culture models. The results showed a substantial increase of cisplatin resistance mediated by 3D microenvironment. This phenotype was independent of p53 status and autophagy activity and was also observed for other cellular models, including lung cancer cells. Such strong decrease on cellular sensitivity was not due to differences on drug-induced DNA damage, since similar levels of γ-H2AX and cisplatin–DNA adducts were detected under both conditions. However, the processing of these cisplatin-induced DNA lesions was very different in 2D and 3D cultures. Unlike cells in monolayer, cisplatin-induced DNA damage is persistent in 3D-cultured cells, which, consequently, led to high senescence induction. Moreover, only 3D-cultured cells were able to progress through S cell cycle phase, with unaffected replication fork progression, due to the upregulation of translesion (TLS) DNA polymerase expression and activation of the ATR-Chk1 pathway. Co-treatment with VE-821, a pharmacological inhibitor of ATR, blocked the 3D-mediated changes on cisplatin response, including low sensitivity and high TLS capacity. In addition, ATR inhibition also reverted induction of REV3L by cisplatin treatment. By using REV3L-deficient cells, we showed that this TLS DNA polymerase is essential for the cisplatin sensitization effect mediated by VE-821. Altogether, our results demonstrate that 3D-cell architecture-associated resistance to cisplatin is due to an efficient induction of REV3L and TLS, dependent of ATR. Thus co-treatment with ATR inhibitors might be a promising strategy for enhancement of cisplatin treatment efficiency in breast cancer patients.

Interaction of tumor-associated macrophages and cancer chemotherapy

It has been recently recognized that the tumor microenvironment (TME) is an essential factor that defines the efficiency of chemotherapy. The local TME, consisting of immune cells with diverse phenotypes and functions, can strongly modulate the response to chemotherapy. Tumor-associated macrophages (TAMs) that display pronounced heterogeneity and phenotypic plasticity are the major innate immune component in the microenvironment of solid tumors. In our review, we elucidate the complex role of TAMs in the progression of different types of solid tumors, summarize the current knowledge about the effects of different anticancer chemotherapeutic agents on monocytes/macrophages, and describe the mechanisms of chemotherapy resistance mediated by TAMs.

Interaction of tumor-associated macrophages and cancer chemotherapy

It has been recently recognized that the tumor microenvironment (TME) is an essential factor that defines the efficiency of chemotherapy. The local TME, consisting of immune cells with diverse phenotypes and functions, can strongly modulate the response to chemotherapy. Tumor-associated macrophages (TAMs) that display pronounced heterogeneity and phenotypic plasticity are the major innate immune component in the microenvironment of solid tumors. In our review, we elucidate the complex role of TAMs in the progression of different types of solid tumors, summarize the current knowledge about the effects of different anticancer chemotherapeutic agents on monocytes/macrophages, and describe the mechanisms of chemotherapy resistance mediated by TAMs.

Cisplatin: The first metal based anticancer drug

Cisplatin or (SP-4-2)-diamminedichloridoplatinum(II) is one of the most potential and widely used drugs for the treatment of various solid cancers such as testicular, ovarian, head and neck, bladder, lung, cervical cancer, melanoma, lymphomas and several others. Cisplatin exerts anticancer activity via multiple mechanisms but its most acceptable mechanism involves generation of DNA lesions by interacting with purine bases on DNA followed by activation of several signal transduction pathways which finally lead to apoptosis. However, side effects and drug resistance are the two inherent challenges of cisplatin which limit its application and effectiveness. Reduction of drug accumulation inside cancer cells, inactivation of drug by reacting with glutathione and metallothioneins and faster repairing of DNA lesions are responsible for cisplatin resistance. To minimize cisplatin side effects and resistance, combination therapies are used and have proven more effective to defect cancers. This article highlights a systematic description on cisplatin which includes a brief history, synthesis, action mechanism, resistance, uses, side effects and modulation of side effects. It also briefly describes development of platinum drugs from very small cisplatin complex to very large next generation nanocarriers conjugated platinum complexes.

JMJD2 promotes acquired cisplatin resistance in non-small cell lung carcinoma cells

Platinum-based drugs such as cisplatin (CP) are the first-line chemotherapy for non-small-cell lung carcinoma (NSCLC). Unfortunately, NSCLC has a low response rate to CP and acquired resistance always occurs. Histone methylation regulates chromatin structure and is implicated in DNA repair. We hypothesize histone methylation regulators are involved in CP resistance. We therefore screened gene expression of known histone methyltransferases and demethylases in three NSCLC cell lines with or without acquired resistance to CP. JMJD2s are a family of histone demethylases that remove tri-methyl groups from H3K9 and H3K36. We found expression of several JMJD2 family genes upregulated in CP-resistant cells, with JMJD2B expression being upregulated in all three CP-resistant NSCLC cell lines. Further analysis showed increased JMJD2 protein expression coincided with decreased H3K9me3 and H3K36me3. Chemical inhibitors of JMJD2-family proteins increased H3K9me3 and H3K36me3 levels and sensitized resistant cells to CP. Mechanistic studies showed that JMJD2 inhibition decreased chromatin association of ATR and Chk1 and inhibited the ATR-Chk1 replication checkpoint. Our results reveal that JMJD2 demethylases are potential therapeutic targets to overcome CP resistance in NSCLC.

Cisplatin-Based Chemotherapy of Human Cancers

Cisplatin (cis-diammine-dichloro-platinum II) was initially discovered to prevent the growth of Escherichia coli and was further recognized for its anti-neoplastic and cytotoxic effects on cancer cells. Administered intravenously to humans, cisplatin is used as first-line chemotherapy treatment for patients diagnosed with various types of malignancies, such as leukemia, lymphomas, breast, testicular, ovarian, head and neck, and cervical cancers, and sarcomas. Once cisplatin enters the cell it exerts its cytotoxic effect by losing one chloride ligand, binding to DNA to form intra-strand DNA adducts, and inhibiting DNA synthesis and cell growth. The DNA lesions formed from cisplatin-induced DNA damage activate DNA repair response via NER (nuclear excision repair system) by halting cisplatin-induced cell death by activation of ATM (ataxia telangiectasia mutated) pathway. Although treatment has been shown to be effective, many patients experience relapse due to drug resistance. As a result, other platinum compounds such as oxaliplatin and carboplatin have since been used and have shown some levels of effectiveness. In this review, the clinical applications of cisplatin are discussed with a special emphasis on its use in cancer chemotherapy.

Carfilzomib enhances cisplatin-induced apoptosis in SK-N-BE(2)-M17 human neuroblastoma cells

Neuroblastoma is a solid malignant tumor of the sympathetic nervous system, which accounts for 8–10% of childhood cancers. Considering the overall high risk and poor prognosis associated with neuroblastoma, effective therapeutics should be developed to improve patient survival and quality of life. A recent study showed that a proteasome inhibitor, carfilzomib (CFZ), reduced cell viability of SK-N-BE(2)-M17 neuroblastoma cells. Therefore, we investigated the molecular mechanisms by which CFZ lower the cell viability of neuroblastoma cells. CFZ reduced cell viability via cell cycle arrest at G2/M and apoptosis, which involved caspase activation (caspases-8, 9, 4, and 3), endoplasmic reticulum stress, reactive oxygen species production, mitochondrial membrane potential loss, and autophagy in a dose- and time-dependent manner. The effect of CFZ was additive to that of cisplatin (Cis), a well-known chemotherapeutic drug, in terms of cell viability reduction, cell cycle arrest, and apoptosis. Importantly, the additive effect of CFZ was maintained in Cis-resistant neuroblastoma cells. These results suggest that CFZ can be used in combination therapy for patients with neuroblastoma to overcome the resistance and adverse side effects of Cis.

Integrative analysis of Paneth cell proteomic and transcriptomic data from intestinal organoids reveals functional processes dependent on autophagy

Paneth cells are key epithelial cells that provide an antimicrobial barrier and maintain integrity of the small-intestinal stem cell niche. Paneth cell abnormalities are unfortunately detrimental to gut health and are often associated with digestive pathologies such as Crohn's disease or infections. Similar alterations are observed in individuals with impaired autophagy, a process that recycles cellular components. The direct effect of autophagy impairment on Paneth cells has not been analysed. To investigate this, we generated a mouse model lacking Atg16l1 specifically in intestinal epithelial cells, making these cells impaired in autophagy. Using three-dimensional intestinal organoids enriched for Paneth cells, we compared the proteomic profiles of wild-type and autophagy-impaired organoids. We used an integrated computational approach combining protein-protein interaction networks, autophagy-targeted proteins and functional information to identify the mechanistic link between autophagy impairment and disrupted pathways. Of the 284 altered proteins, 198 (70%) were more abundant in autophagy-impaired organoids, suggesting reduced protein degradation. Interestingly, these differentially abundant proteins comprised 116 proteins (41%) that are predicted targets of the selective autophagy proteins p62, LC3 and ATG16L1. Our integrative analysis revealed autophagy-mediated mechanisms that degrade key proteins in Paneth cell functions, such as exocytosis, apoptosis and DNA damage repair. Transcriptomic profiling of additional organoids confirmed that 90% of the observed changes upon autophagy alteration have effects at the protein level, not on gene expression. We performed further validation experiments showing differential lysozyme secretion, confirming our computationally inferred downregulation of exocytosis. Our observations could explain how protein-level alterations affect Paneth cell homeostatic functions upon autophagy impairment.This article has an associated First Person interview with the joint first authors of the paper.

Therapeutic efficacy of intra-tumor AvidinOX and low systemic dose biotinylated cetuximab, with and without cisplatin, in an orthotopic model of head and neck cancer

In a previous study, the efficacy of low intraperitoneal doses of biotinylated cetuximab (bCet) in mice with subcutaneous tumor xenografts of human head and neck cancer (HNC) treated intra-tumors with AvidinOX was reported. Taking into account that the current standard treatment for HNC is the combination of cetuximab and cisplatin, the present study investigated the activity of AvidinOX-targeted bCet with and without cisplatin in an orthotopic model. The results confirmed that administration of intra-tumor AvidinOX makes an otherwise inactive dose of bCet effective in reducing tumor growth, and the addition of a low dose of cisplatin further improved tumor growth inhibition. Supporting the in vivo data, immunohistochemical staining of tumor masses from mice treated with AvidinOX, bCet and cisplatin exhibited the highest tumor cell damage and the lowest angiogenic activity among all treatment groups, measured as the number of γ-H2A.X and cleaved caspase-3-positive cells, and vascular endothelial growth factor-C and platelet and endothelial cell adhesion molecule 1-positive cells, respectively. AvidinOX is currently under clinical investigation to assess its use in delivering radioactive biotin to inoperable tumor lesions (ClinicalTrials.gov: NCT02053324 and NCT03188328). The present study further supported the potential clinical use of AvidinOX to target low bCet doses to inoperable tumor lesions, with or without an additional low dose of cisplatin. Since low doses of highly expensive monoclonal antibodies become effective with AvidinOX and low dose cisplatin, such therapies promise to be cheaper and less toxic than current treatments.

Molecular mechanisms of cisplatin-induced nephrotoxicity: a balance on the knife edge between renoprotection and tumor toxicity

Background

Cisplatin (cis-diamminedichloroplatinum II, CDDP) is one of the most effective chemotherapeutic agents. However, its clinical use is limited due to the severe side effects, including nephrotoxicity and acute kidney injury (AKI) which develop due to renal accumulation and biotransformation of CDDP. The alleviation or prevention of CDDP-caused nephrotoxicity is currently accomplished by hydration, magnesium supplementation or mannitol-induced forced diuresis which is considered for high-dose CDDP-treated patients. However, mannitol treatment causes over-diuresis and consequent dehydration in CDDP-treated patients, indicating an urgent need for the clinical use of safe and efficacious renoprotective drug as an additive therapy for high dose CDDP-treated patients.

Main body

In this review article we describe in detail signaling pathways involved in CDDP-induced apoptosis of renal tubular cells, oxidative stress and inflammatory response in injured kidneys in order to pave the way for the design of new therapeutic approaches that can minimize CDDP-induced nephrotoxicity. Most of these molecular pathways are, at the same time, crucially involved in cytotoxic activity of CDDP against tumor cells and potential alterations in their function might mitigate CDDP-induced anti-tumor effects.

Conclusion

Despite the fact that many molecules were designated as potential therapeutic targets for renoprotection against CDDP, modulation of CDDP-induced nephrotoxicity still represents a balance on the knife edge between renoprotection and tumor toxicity.

Targeting Burkitt lymphoma with a tumor cell-specific heptamethine carbocyanine-cisplatin conjugate

BACKGROUND

Burkitt lymphoma is a fast-growing mature B cell malignancy, whose genetic hallmark is translocation and activation of the c-myc gene. Prompt multiagent immunochemotherapy regimens can have favorable outcomes, but prognosis is poor in refractory or relapsed disease. We previously identified a novel family of near-infrared heptamethine carbocyanine fluorescent dyes (HMCD or DZ) with tumor-homing properties via organic anion-transporting peptides. These membrane carriers have uptake in tumor cells but not normal cells in cell culture, mouse and dog tumor models, patient-derived xenografts, and perfused kidney cancers in human patients.

METHODS

Here we report the cytotoxic effects of a synthesized conjugate of DZ with cisplatin (CIS) on B cell lymphoma CA46, Daudi, Namalwa, Raji, and Ramos cell lines in cell culture and in xenograft tumor formation. Impaired mitochondrial membrane permeability was examined as the mechanism of DZ-CIS-induced lymphoma cell death.

RESULTS

The new conjugate, DZ-CIS, is cytotoxic against Burkitt lymphoma cell lines and tumor models. DZ-CIS retains tumor-homing properties to mitochondrial and lysosomal compartments, does not accumulate in normal cells and tissues, and has no nephrotoxicity in mice. DZ-CIS accumulated in Burkitt lymphoma cells and tumors induces apoptosis and retards tumor cell growth in culture and xenograft tumor growth in mice.

CONCLUSION

DZ-CIS downregulated c-myc and overcame CIS resistance in myc-driven TP53-mutated aggressive B cell Burkitt lymphoma. We propose that DZ-CIS could be used to treat relapsed/refractory aggressive Burkitt lymphomas.

Expression of the lncRNA ZFAS1 in cervical cancer and its correlation with prognosis and chemosensitivity

OBJECTIVE

To investigate the expression of the lncRNA ZFAS1 in cervical cancer and its relationship with patient prognosis and cervical cancer cell chemosensitivity.

METHODS

The expression of ZFAS1 in cervical cancer tissues and cell lines was detected by qRT-PCR. The cervical cancer CaSki and the HeLa cell lines were transfected to be divided into Blank, siR-Control, and siR-ZFAS1 groups. MTT, wound-healing, and transwell assays were used to evaluate cell biological function. Cisplatin with different concentrations was used to treat cells in different transfection groups, and MTT assays were used to detect the cell growth inhibition rate and the half-inhibitory concentration (IC50) of cisplatin was measured. Cell apoptosis was determined by flow cytometry. A xenograft mouse model was used to investigate the effects of siR-ZFAS1 on the chemosensitivity to cisplatin.

RESULTS

ZFAS1 was significantly upregulated in cervical cancer tissues and cell lines, and increased ZFAS1 levels led to poor prognoses in patients. In addition, cells in the siR-ZFAS1 group showed remarkably reduced ZFAS1 expression as well as cell proliferation, invasion and migration. After being treated with cisplatin at different concentrations, cells in the siR-ZFAS1 group had dramatically increased cell growth inhibition and apoptosis but lower cisplatin IC50s. In addition, siR-ZFAS1 reduced the volumes and weights of tumors in nude mice treated with cisplatin and enhanced the chemosensitivity of cervical cancer cells to cisplatin.

CONCLUSION

The lncRNA ZFAS1 was upregulated in cervical cancer tissues, and its high expression indicated a poor prognosis. Silencing ZFAS1 may inhibit cell proliferation, migration and invasion and enhance cisplatin chemosensitivity.

Differential damage and repair of DNA-adducts induced by anti-cancer drug cisplatin across mouse organs

The platinum-based drug cisplatin is a widely used first-line therapy for several cancers. Cisplatin interacts with DNA mainly in the form of Pt-d(GpG) di-adduct, which stalls cell proliferation and activates DNA damage response. Although cisplatin shows a broad spectrum of anticancer activity, its utility is limited due to acquired drug resistance and toxicity to non-targeted tissues. Here, by integrating genome-wide high-throughput Damage-seq, XR-seq, and RNA-seq approaches, along with publicly available epigenomic data, we systematically study the genome-wide profiles of cisplatin damage formation and excision repair in mouse kidney, liver, lung and spleen. We find different DNA damage and repair spectra across mouse organs, which are associated with tissue-specific transcriptomic and epigenomic profiles. The framework and the multi-omics data we present here constitute an unbiased foundation for understanding the mechanisms of cellular response to cisplatin. Our approach should be applicable for studying drug resistance and for tailoring cancer chemotherapy regimens.

RAP80 expression in breast cancer and its relationship with apoptosis in breast cancer cells

Background

RAP80 is a member of BRCA1-A complex, which plays an important role in regulating the cell cycle checkpoint and DNA damage repair in the nucleus.

Method

We investigated RAP80 expression in breast cancer and its paired normal breast tissues to further analyze its role in the biological behavior of breast cancer cells.

Results

RAP80 expression in breast cancer (62.3%, 101/162) was significantly lower than that in adjacent normal breast tissues (P<0.05). RAP80 expression was related to tumor size, lymph node metastasis, TNM stage, and molecular subtype (P<0.05). RAP80 mRNA expression was significantly lower in triple-negative breast cancer than other types. The mRNA and protein of RAP80 were obvious in MCF-7 and very weak in ZR-75 or MDA-MB-231, so we picked MCF-7 to be transfected with RAP80 siRNA. The survival rate of both cells decreased in a dose-dependent manner and the IC50 value for cisplatin in MCF-7 RAP80 siRNA cells was 0.83 µg/mL, and 1.69 µg/mL in wild-type MCF-7 according to MTT. RAP80 siRNA transfection upregulated the apoptosis and downregulated invasive or migrating ability of MCF-7. RAP80 siRNA also upregulated the protein expression of Caspase-3, cleaved Caspase-3, Apaf-1, Cytochrome C, Bax, and Fas, and downregulated the protein expression of Bcl-2.

Conclusion

RAP80 expression was related to ER or PR activity. Inhibition of RAP80 expression can induce apoptosis in breast cancer cells and improve chemosensitivity to cisplatin. Tumor cells can activate protective responses to inhibit cell cycle progression, which may be related to RAP80, and repair cisplatin-induced DNA damage. RAP80 is related to BRCA1's effect, which can be used as an interesting target for pharmacological modulation that can increase the efficiency of cisplatin chemotherapy.

Novel Palladium Complex: Cytotoxicity against Cisplatin-resistant K562 Cells

Today, development of resistance to anticancer drugs (including cisplatin) is noticed as a major problem. Recently several studies demonstrated that palladium complexes showed remarkable cytotoxic effects against K562 cell line and could be used efficiently for treatment of many human cancers including leukemia. Hereof, K562 cells were made resistant to cisplatin using increasing concentration of cisplatin up to 4.5 mM and then cytotoxic effect of synthesized palladium complex was evaluated on this sub-line using MTT assay. Annexin V/PI staining using flow cytometry and scanning electron microscopy (SEM) were performed to find out the mechanism of the observed cytotoxicity. Results indicated that tested compounds had a noticeable cytotoxic effect on K562 cells 80 times more than cisplatin. Palladium complex also showed significant cytotoxicity on resistant K562 sub-line. Flow cytometry and SEM results revealed that these compounds exert their cytotoxic effect via apoptosis and it could be concluded that the novel synthesized palladium complex might be a good candidate for replacing cisplatin in case of treatment of cisplatin resistant tumors.

Cisplatin-induced DNA double-strand breaks promote meiotic chromosome synapsis in PRDM9-controlled mouse hybrid sterility

PR domain containing 9 (Prdm9) is specifying hotspots of meiotic recombination but in hybrids between two mouse subspecies Prdm9 controls failure of meiotic chromosome synapsis and hybrid male sterility. We have previously reported that Prdm9-controlled asynapsis and meiotic arrest are conditioned by the inter-subspecific heterozygosity of the hybrid genome and we presumed that the insufficient number of properly repaired PRDM9-dependent DNA double-strand breaks (DSBs) causes asynapsis of chromosomes and meiotic arrest (Gregorova et al., 2018). We now extend the evidence for the lack of properly processed DSBs by improving meiotic chromosome synapsis with exogenous DSBs. A single injection of chemotherapeutic drug cisplatin increased frequency of RPA and DMC1 foci at the zygotene stage of sterile hybrids, enhanced homolog recognition and increased the proportion of spermatocytes with fully synapsed homologs at pachytene. The results bring a new evidence for a DSB-dependent mechanism of synapsis failure and infertility of intersubspecific hybrids.

Biological alterations in renal and hepatic tissues by a novel gold (III) anti-cancerous compound

Objective(s):

Newer organo-metallic, specifically gold (III) complexes with multiple ligands are currently being formulated with primary focus of having increased anti-cancerous properties and decreased cytotoxicity. In this study, histological toxicity profile of a newly formulated anti-cancerous gold (III) compound [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) was investigated by evaluation of kidney and liver tissues of rats treated by the compound.

Materials and Methods:

This is a quasi-experimental study. In acute toxicity component of the study, (n = 16) male rats weighing between 200–250 g were administered single, variable concentration of the gold (III) compound, [trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) to determine LD₅₀ (dose that is lethal to 50% of rats). An IP injection of 2.3 mg/kg (equivalent to 1/10 of LD₅₀) was injected for 14 consecutive days to (n=10) male rats in the sub-acute component of the study. Autopsy preservation of liver and kidney tissue in buffered formalin, sample processing, histopathological evaluation, and comparison with unremarkable controls (n=5) was conducted sequentially.

Results:

A dose of 2.3 mg/kg did not produce any tubular necrosis in kidney specimens. Mild interstitial inflammation with prominence of plasma cells was the main histological alteration. Plasmacytic pyelitis was also seen. Varying extents of cytoplasmic vacuolization and mild focal lobular and portal inflammation were predominant hepatic microscopic findings.

Conclusion:

[trans-(±)-1,2-(DACH)₂Au]Cl₃ Bis(trans-1,2-Diaminocyclohexane) produced no histological damage in renal and hepatic tissues of rats. This very limited sample animal-based study points to the relative safety of this new gold compound. However, there is a need to compare this compound with established drugs in a comparative non-animal based study.

Demethoxycurcumin-Loaded Chitosan Nanoparticle Downregulates DNA Repair Pathway to Improve Cisplatin-Induced Apoptosis in Non-Small Cell Lung Cancer

Demethoxycurcumin (DMC), through a self-assembled amphiphilic carbomethyl-hexanoyl chitosan (CHC) nanomatrix has been successfully developed and used as a therapeutic approach to inhibit cisplatin-induced drug resistance by suppressing excision repair cross-complementary 1 (ERCC1) in non-small cell lung carcinoma cells (NSCLC). Previously, DMC significantly inhibited on-target cisplatin resistance protein, ERCC1, via PI3K-Akt-snail pathways in NSCLC. However, low water solubility and bioavailability of DMC causes systemic elimination and prevents its clinical application. To increase its bioavailability and targeting capacity toward cancer cells, a DMC-polyvinylpyrrolidone core phase was prepared, followed by encapsulating in a CHC shell to form a DMC-loaded core-shell hydrogel nanoparticles (DMC-CHC NPs). We aimed to understand whether DMC-CHC NPs efficiently potentiate cisplatin-induced apoptosis through downregulation of ERCC1 in NSCLC. DMC-CHC NPs displayed good cellular uptake efficiency. Dissolved in water, DMC-CHC NPs showed comparable cytotoxic potency with free DMC (dissolved in DMSO). A sulforhodamine B (SRB) assay indicated that DMC-CHC NPs significantly increased cisplatin-induced cytotoxicity by highly efficient intracellular delivery of the encapsulated DMC. A combination of DMC-CHC NPs and cisplatin significantly inhibited on-target cisplatin resistance protein, ERCC1, via the PI3K-Akt pathway. Also, this combination treatment markedly increased the post-target cisplatin resistance pathway including bax, and cytochrome c expressions. Thymidine phosphorylase (TP), a main role of the pyrimidine salvage pathway, was also highly inhibited by the combination treatment. The results suggested that enhancement of the cytotoxicity to cisplatin via administration of DMC-CHC NPs was mediated by down-regulation of the expression of TP, and ERCC1, regulated via the PI3K-Akt pathway.

Relations between approved platinum drugs and non-coding RNAs in mesothelioma

Malignant mesothelioma diseases feature an increasing risk due to their severe forms and their association with asbestos exposure. Platinum(II) complexes such as cisplatin and carboplatin are clinically approved for the therapy of mesothelioma often in combination with antimetabolites such as pemetrexed or gemcitabine. It was observed that pathogenic properties of mesothelioma cells and the response of mesothelioma tumors towards platinum-based drugs are strongly influenced by non-coding RNAs, in particular, by small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). These non-coding RNAs controlled drug sensitivity and the development of tumor resistance towards platinum drugs. An overview of the interactions between platinum drugs and non-coding RNAs is given and the influence of non-coding RNAs on platinum drug efficacy in mesothelioma is discussed. Suitable non-coding RNA-modulating agents with potentially beneficial effects on cisplatin treatment of mesothelioma diseases are mentioned. The understanding of mesothelioma diseases concerning the interactions of non-coding RNAs and platinum drugs will optimize existing therapy schemes and pave the way to new treatment options in future.

The effect of cisplatin administration on certain trace elements homeostasis in rats and the protective effect of silver birch (Betula pendula) sap

BACKGROUND

A clinically active structure with known antitumor activities is cisplatin (CDDP), but this it comes with toxicity characteristics which can be faded by the beneficial effects of Silver birch (Betula pendula) sap.

OBJECTIVE

We aimed to assess the cisplatin activity on: Mn, Mg, Cu, Fe and Zn homeostasis in rats and to observe the effect of birch sap.

METHODS

Healthy Wistar rats (n = 10/group) were divided in four groups: Control: receiving 1 mL saline I.P. way + water; E1: cisplatin 20 mg kgbw^-1, I.P.; E2: cisplatin 20 mg kgbw^-1, I.P. + birch sap and Control sap group: 1 mL saline I.P. + birch sap. Blood was collected: at the trial's start and after 48 h, and blood and organs (liver, kidney and spleen) for the cytoarchitecture investigation and readings were sampled after seven days. Samples were processed in nitric acid by microwave digestion and readings were completed by flame atomic absorption spectroscopy, the outcomes being statistically analyzed by ANOVA.

RESULTS

Cisplatin produced a significant imbalance in the trace elements homeostasis, the birch sap administration recovering them usual homeostasis status. Comparatively with the Control, rats exposed to cisplatin presented a not significant (p > 0.05) decrease of Zn (-26.74%) and Mg (-10.25%), a significant (p < 0.05) decrease of Cu (-27.73%) at 48 h, a highly significant (p < 0.01) decrease of Cu (-56.08%) and Fe (-85.35%) at seven days after administration and a not significant (p > 0.05) increase of Mn (+28.16%). Birch sap administration after Cisplatin was followed by restoration or nevertheless significant increase (p < 0.05) of the investigated trace elements Zn (+56.88% to 48 h/+89.94% after seven days), Mg (+26.86%/+95.74%), Cu (+23.13%/+74.56%), Fe (+39.64%/+440.11%) and Mn (+4.30%/+15.87%), suggesting them defence against cisplatin. Histology revealed the order of main altered organs after the CDDP exposure: kidney, spleen and liver.

CONCLUSIONS

The study recommended the important protective role of Betula pendula sap against diverse cisplatin deleterious side-effects.

XPA, XPC, and XPD Modulate Sensitivity in Gastric Cisplatin Resistance Cancer Cells

Cisplatin is an election drug widely used in clinic for the treatment of advanced gastric cancer. However, the heterogeneity of the gastric tumors and its resistance to the drugs, make in some cases the response very low and the prognosis unpredictable. In this manuscript we aim to find the molecular processes involved in cisplatin-induced apoptosis in two gastric cancer cell lines with different sensitivity to the treatment: AGS and MKN45. The apoptosis induction is higher in MKN45 than in AGS cells in response to CDDP. The intrinsic apoptotic pathway study revealed that MKN45 cells undergo degradation of Mcl-1 together with an increase of Bid and Bad levels, which results in sensitivity to CDDP. In addition, DNA repair NER pathway is impair in MKN45 cells due to low levels of XPC and the absence of translocation of XPA and XPD to the nucleus after stimuli. Altogether, these results suggest that NER and Bcl-2 protein family proteins are potential targets to improve the response to cisplatin treatment.

Expression of Insulin-Like Growth Factor Binding Protein-5 (IGFBP5) Reverses Cisplatin-Resistance in Esophageal Carcinoma

Cisplatin (CDDP) is one of the front-line chemotherapeutic drugs used in the treatment of esophageal squamous cell carcinoma (ESCC). Occurrence of resistance to CDDP has become one of the main challenges in cancer therapy. In this study, the gene expression profile of CDDP-resistant ESCC cells was investigated and molecular approaches were explored in an attempt to reverse the CDDP resistance. A CDDP-resistant SLMT-1/CDDP1R cell line was established from SLMT-1 cells by subculturing in the medium containing an increasing concentration of CDDP (0.1–1μg/mL). Mitochondrial (MTS) cytotoxicity assay, cell proliferation assay and cell morphology were used to assess the acquisition of cisplatin-resistance. The most differentially expressed gene in SLMT-1/CDDP1R cells was identified by cDNA microarray analysis compared with the parental SLMT-1 cells and validated by quantitative real-time polymerase chain reaction (qPCR). Association between expression of the most differentially expressed target gene to cisplatin-resistance was verified by RNA interference. An attempt to reversecisplatin-resistance phenotypes was made by using the vector expressing the most downregulated target gene in the CDDP-resistant cells. A CDDP-resistant ESCC cell line, SLMT-1/CDDP1R, was established with 2.8-fold increase CDDP-resistance (MTS₅₀ = 25.8 μg/mL) compared with the parental SLMT-1 cells. cDNA microarray analysis revealed that IGFBP5 showed the highest level of downregulation in SLMT-1/CDDP1R cells compared with the parental SLMT-1 cells. Suppression of IGFBP5 mediated by IGFBP5-targeting siRNA in parental SLMT-1 cells confirmed that IGFBP5 suppression in ESCC cells would induce CDDP-resistance. More importantly, upregulation of IGFBP5 using IGFBP5 expression vector reduced cisplatin-resistance in SLMT-1/CDDP1R cells by 41%. Thus, our results demonstrated that IGFBP5 suppression is one of the mechanisms for the acquisition of cisplatin-resistance in ESCC cells. Cisplatin-resistance phenotype can be reversed by increasing the expression level of IGFBP5. The overall findings of this study thus offered a new direction for reversing the CDDP resistance in ESCC and possibly in other cancer types with further investigations in future.

Acute toxic effects of ruthenium (II)/amino acid/diphosphine complexes on Swiss mice and zebrafish embryos

Anticancer potential of ruthenium complexes has been widely investigated, but safety evaluation studies are still scarce. Despite of ruthenium-based anticancer agents are known to cause fewer side effects compared to other metal-based drugs, these compounds are not fully free of toxicity, causing mainly nephrotoxicity. Based on the promising results from antitumor activity of the complexes [Ru(L-Met)(bipy)(dppb)]PF₆ (RuMet) and [Ru(L-Trp)(bipy)(dppb)]PF₆ (RuTrp), for the first time we investigated the toxicity profile of these complexes in rodent and zebrafish models. The acute oral toxicity was evaluated in Swiss mice. The mutagenic and genotoxic potential was determined by a combination of Micronucleus (MN) and Comet assay protocols, after exposure of Swiss mice to RuMet and RuTrp in therapeutic doses. Zebrafish embryos were exposed to these complexes, and their development observed up to 96 h post-fertilization. RuMet and RuTrp complexes showed low acute oral toxicity. Recorded behavioral changes were not recorded, nor were macroscopic morphological changes or structural modifications in the liver and kidneys. These complexes did not cause genetic toxicity, presenting a lack of micronuclei formation and low DNA damage induction in the cells from Swiss mice. In contradiction, cisplatin treatment exhibited high mutagenicity and genotoxicity. RuMet and RuTrp showed low toxicity in the embryo development of zebrafish. The RuMet and RuTrp complexes demonstrated low toxicity in the two study models, an interesting property in preclinical studies for novel anticancer agents.

Activity profile of the cisplatin analogue PN149 in different tumor cell lines

The efficacy of the anticancer drug cisplatin is restricted by tumor cell resistance and occurrence of severe side effects. One strategy to overcome these limitations is the development of new, improved platinum drugs. Previous investigations showed that platinum(IV)-nitroxyl complexes are able to circumvent cisplatin resistance in bladder cancer cells. In the present study the mode of action of the platinum(IV)-nitroxyl complex PN149 was investigated in the bladder cancer cell line RT112 and the renal cell carcinoma cell line A498 on the molecular and cellular level. Gene expression analysis showed that PN149 induced genes related to DNA damage response (RRM2B, GADD45A), cell cycle regulation (CDKN1A, PLK3, PPM1D) as well as those coding for the pro-apoptotic factors PUMA and Noxa. These findings on the transcriptional level were confirmed on the functional level revealing that PN149 treatment increased levels of p53 and resulted in cell cycle arrest and drug-induced cytotoxicity via induction of apoptosis. Regarding the expression of oxidative-stress sensitive genes, PN149 induced FTH1, GCLC, HMOX1 and TXNRD1 but relevant effects were restricted to RT112 cells treated with 50 µM. The pro-inflammatory IL-8 was induced by PN149 in RT112 but not A498 cells indicating a cell-type specific activation. Taken together, PN149 possessed promising activity in different tumor cell lines rendering it an interesting alternative to cisplatin in chemotherapy.

Millepachine showed novel antitumor effects in cisplatin-resistant human ovarian cancer through inhibiting drug efflux function of ATP-binding cassette transporters

Millepachine (MIL), a bioactive natural chalcone from Chinese herbal medicine Millettia pachycarpa Benth, exhibits strong antitumor effects against many human cancer cells both in vitro and in vivo. In this study, we found that MIL significantly inhibited the proliferation of cisplatin-resistant A2780CP cells via inducing obvious G2/M arrest and apoptosis and down-regulating the activity of topoisomerase II protein. We further found that the mechanism by which MIL showed good antitumor effects in cisplatin-resistant human ovarian cancer was associated with inhibiting the expression of ATP-binding cassette transporters in cisplatin-resistant A2780CP cells. Importantly, MIL did not only significantly inhibit the tumor growth in cisplatin-sensitive A2780S xenograft model, with an inhibitory rate of 73.21%, but also inhibited the tumor growth in the cisplatin-resistant A2780CP xenograft model, with an inhibitory rate of 65.68% (p < 0.001 vs. control; p < 0.001 vs. DDP). In addition, MIL did not induce acquired drug resistance in A2780S tumor-bearing mice with an inhibitory rate of 60.03%. The promising in vitro and in vivo performance indicated that MIL exhibited potential significance for drug research and development.

Asteriscus graveolens Extract in Combination with Cisplatin/Etoposide/Doxorubicin Suppresses Lymphoma Cell Growth through Induction of Caspase-3 Dependent Apoptosis

Chemotherapy drugs action against cancer is not selective, lead to adverse reactions and drug resistance. Combination therapies have proven more effective in defeating cancers. We hypothesize that plant extract/fraction contains many/several compounds and as such can target multiple pathways as cytotoxic agent and may also have chemo sensitizing activities. We designed a study in which, Asteriscus graveolens (Forssk.) Less (A. graveolens)-derived fraction that contains sesquiterpene lactone asteriscunolide isomers (AS) will be tested in combination with known chemotherapy drugs. Successful combination will permit to reduce chemotherapy drugs concentration and still get the same impact on cancer cells. Sesquiterpene lactone such as asteriscunolide isomers is a naturally occurring compound found in a variety of fruits, vegetables, and medicinal plants with anti-cancer properties. The experiments presented here showed that adding plant fraction containing AS permit reducing the concentration of cisplatin/etoposide/doxorubicin in order to reduce mouse BS-24-1 lymphoma cells (BS-24-1 cells) survival. It involved enhancing the production of Reactive Oxygen Species (ROS), activation of caspase-3 and inhibition of Topoisomerase I activity. Taken together, the results suggest that A. graveolens fraction sensitized BS-24-1 cells to cisplatin/etoposide/doxorubicin through induction of ROS and caspase-3-dependent apoptosis.

Thymidine Metabolism as a Confounding Factor for 3'-Deoxy-3'-18F-Fluorothymidine Uptake After Therapy in a Colorectal Cancer Model

Noninvasive monitoring of tumor therapy response helps in developing personalized treatment strategies. Here, we performed sequential PET and diffusion-weighted MRI to evaluate changes induced by a FOLFOX-like combination chemotherapy in colorectal cancer xenografts, to identify the cellular and molecular determinants of these imaging biomarkers. Methods: Tumor-bearing CD1 nude mice, engrafted with FOLFOX-sensitive Colo205 colorectal cancer xenografts, were treated with FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) weekly. On days 1, 2, 6, 9, and 13 of therapy, tumors were assessed by in vivo imaging and ex vivo analyses. In addition, HCT116 xenografts, which did not respond to the FOLFOX treatment, were imaged on day 1 of therapy. Results: In Colo205 xenografts, FOLFOX induced a profound increase in uptake of the proliferation PET tracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) accompanied by increases in markers for proliferation (Ki-67, thymidine kinase 1) and for activated DNA damage response (γH2AX), whereas the effect on cell death was minimal. Because tracer uptake was unaltered in the HCT116 model, these changes appear to be specific for tumor response. Conclusion: We demonstrated that 18F-FLT PET can noninvasively monitor cancer treatment-induced molecular alterations, including thymidine metabolism and DNA damage response. The cellular or imaging changes may not, however, be directly related to therapy response as assessed by volumetric measurements.

Emerging role of long non-coding RNAs in cisplatin resistance

Cisplatin (CDDP) is one of the most commonly used chemotherapy drugs for the treatment of various cancers. Although platinum-based therapies are highly efficacious against rapidly proliferating malignant tumors, the development of CDDP resistance results in significant relapse as well as decreased overall survival rates, which is a significant obstacle in CDDP-based cancer therapy. Long non-coding RNAs (lncRNAs) are involved in cancer development and progression by the regulation of processes related to chromatin remodeling, transcription, and posttranscriptional processing. Emerging evidence has recently highlighted the roles of lncRNAs in the development of CDDP resistance. In this review, we discuss the roles and mechanisms of lncRNAs in CDDP chemoresistance, including changes in cellular uptake or efflux of a drug, intracellular detoxification, DNA repair, apoptosis, autophagy, cell stemness, and the related signaling pathways, aiming to provide potential lncRNA-targeted strategies for overcoming drug resistance in cancer therapy.

Determining the Radiation Enhancement Effects of Gold Nanoparticles in Cells in a Combined Treatment with Cisplatin and Radiation at Therapeutic Megavoltage Energies

Combined use of chemotherapy and radiation therapy is commonly used in cancer treatment, but the toxic effects on normal tissue are a major limitation. This study assesses the potential to improve radiation therapy when combining gold nanoparticle (GNP) mediated radiation sensitization with chemoradiation compared to chemoradiation alone. Incorporation of GNPs with 2 Gy, 6 MV (megavoltage) radiation resulted in a 19 ± 6% decrease in survival of MDA-MB-231 cells. Monte-Carlo simulations were performed to assess dosimetric differences in the presence of GNPs in radiation. The results show that physics dosimetry represents a small fraction of the observed effect. The survival fraction of the cells exposed to GNPs, cisplatin, and radiation was 0.16 ± 0.007, while cells treated with cisplatin and radiation only was 0.23 ± 0.011. The presence of GNPs resulted in a 30 ± 6% decrease in the survival, having an additive effect. The concentration of the GNPs and free drug used for this study was 0.3 and 435 nM, respectively. These concentrations are relatively lower and achievable in an in vivo setting. Hence, the results of our study would accelerate the incorporation of GNP-mediated chemoradiation into current cancer therapeutic protocols in the near future.

TP53 Arg72Pro polymorphism is associated with increased overall survival but not response to therapy in Portuguese/Caucasian patients with advanced cervical cancer

Identification of mechanisms that influence the therapeutic response and survival in patients with cancer is important. It is known that the genetic variability of the host, including presence of genetic polymorphisms in genes involved in DNA damage response, serves a crucial role in the prognosis of these patients. The present hospital-based retrospective cohort study aimed to evaluate the influence of TP53 Arg72Pro (rs1042522) polymorphism in the clinical outcome of 260 Caucasian patients diagnosed with cervical cancer and treated with concomitant radiotherapy and chemotherapy. The polymorphism genotyping was assessed using allelic discrimination by quantiative polymerase chain reaction. The results indicate that the TP53 Arg72Pro polymorphism did not significantly impact the response to therapy (P=0.571) nor disease-free survival (P=0.081). However, the polymorphism did influence overall survival, as increased median survival time was observed for patients carrying Arg/Pro genotype when compared with patients with Arg/Arg and Pro/Pro genotypes (126 months vs. 111 months, respectively; P=0.047). To conclude, the present findings suggest that a pharmacogenomic profile based on the genetic background of patients, including the analysis of the TP53 genotypes, may individualize treatment nad assist in the selection of therapies that may improve clinical outcome and lower toxicity for the patients.

ERβ alters the chemosensitivity of luminal breast cancer cells by regulating p53 function

Estrogen receptor α (ERα)-positive breast cancers tend to develop resistance to both endocrine therapy and chemotherapy. Despite recent progress in defining molecular pathways that confer endocrine resistance, the mechanisms that regulate chemotherapy response in luminal tumors remain largely elusive. Luminal tumors often express wild-type p53 that is a major determinant of the cellular DNA damage response. Similar to p53, the second ER subtype, ERβ, has been reported to inhibit breast tumorigenesis by acting alone or in collaboration with p53. However, a synergistic mechanism of action has not been described. Here, we suggest that ERβ relies on p53 to elicit its tumor repressive actions in ERα-positive breast cancer cells. Upregulation of ERβ and treatment with ERβ agonists potentiates the tumor suppressor function of p53 resulting in decreased survival. This effect requires molecular interaction between the two proteins that disrupts the inhibitory action of ERα on p53 leading to increased transcriptional activity of p53. In addition, we show that the same interaction alters the chemosensitivity of endocrine-resistant cells including their response to tamoxifen therapy. Our results suggest a collaboration of ERβ and p53 tumor suppressor activity in breast cancer cells that indicates the importance of ligand-regulated ERβ as a tool to target p53 activity and improve the clinical management of resistant disease.

MTH1 deficiency selectively increases non-cytotoxic oxidative DNA damage in lung cancer cells: more bad news than good?

Background

Targeted therapies are based on exploiting cancer-cell-specific genetic features or phenotypic traits to selectively kill cancer cells while leaving normal cells unaffected. Oxidative stress is a cancer hallmark phenotype. Given that free nucleotide pools are particularly vulnerable to oxidation, the nucleotide pool sanitising enzyme, MTH1, is potentially conditionally essential in cancer cells. However, findings from previous MTH1 studies have been contradictory, meaning the relevance of MTH1 in cancer is still to be determined. Here we ascertained the role of MTH1 specifically in lung cancer cell maintenance, and the potential of MTH1 inhibition as a targeted therapy strategy to improve lung cancer treatments.

Methods

Using siRNA-mediated knockdown or small-molecule inhibition, we tested the genotoxic and cytotoxic effects of MTH1 deficiency on H23 (p53-mutated), H522 (p53-mutated) and A549 (wildtype p53) non-small cell lung cancer cell lines relative to normal MRC-5 lung fibroblasts. We also assessed if MTH1 inhibition augments current therapies.

Results

MTH1 knockdown increased levels of oxidatively damaged DNA and DNA damage signaling alterations in all lung cancer cell lines but not normal fibroblasts, despite no detectable differences in reactive oxygen species levels between any cell lines. Furthermore, MTH1 knockdown reduced H23 cell proliferation. However, unexpectedly, it did not induce apoptosis in any cell line or enhance the effects of gemcitabine, cisplatin or radiation in combination treatments. Contrastingly, TH287 and TH588 MTH1 inhibitors induced apoptosis in H23 and H522 cells, but only increased oxidative DNA damage levels in H23, indicating that they kill cells independently of DNA oxidation and seemingly via MTH1-distinct mechanisms.

Conclusions

MTH1 has a NSCLC-specific p53-independent role for suppressing DNA oxidation and genomic instability, though surprisingly the basis of this may not be reactive-oxygen-species-associated oxidative stress. Despite this, overall our cell viability data indicates that targeting MTH1 will likely not be an across-the-board effective NSCLC therapeutic strategy; rather it induces non-cytotoxic DNA damage that could promote cancer heterogeneity and evolution.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4332-7) contains supplementary material, which is available to authorized users.

Cisplatin-induced ERK1/2 activity promotes G1 to S phase progression which leads to chemoresistance of ovarian cancer cells

The link between ERK1/2 activity and cisplatin cytotoxicity, in association with the cell cycle, in ovarian cancer cell lines resistant (A2780cis; SK-OV-3) and sensitive (A2780) to cisplatin was determined. We observed that cisplatin, at a low concentration enhanced the activation of ERK1/2 in A2780 cells and increased their accumulation in the S phase, resulting in low cytotoxicity. A high concentration of drug induced dephosphorylation and degradation of ERK1/2 and was extremely toxic, accumulating most of to these cells in the sub-G1 phase. The PD98059, pharmacological inhibitor of ERK1/2 activation, increased the cytotoxicity of cisplatin applied at a low concentration to A2780 cells (decreased ERK1/2 activity), causing shift of cell accumulation from the S to G1 phase. Surprisingly, PD98059 enhanced cell viability when a chemotherapeutic was used at high concentration, intensifying phosphorylation level of ERK1/2 and reversing cell cycle arrest in sub-G1 to promote the G1 and S phases. A2780cis cells demonstrated resistance to cisplatin with high ERK1/2 activity and accumulation of cells in the G1 and S phases. PD98059 sensitized resistant cells to drug toxicity during the first 24 hours of treatment, with blocked ERK1/2 phosphorylation and prevented progression from the G1 to S phase. SK-OV-3 resistant cells characterized with extremely high basal phosphorylation of ERK1/2, which wasn't changed after exposure to cisplatin. Administration of PD98059 didn't change the cytotoxicity of cisplatin in these cells. In conclusion, ERK1/2, activated by cisplatin, participates in the cell cycle progression from the G1 to S phase, enhancing cells’ survival and drug resistance.

Combination Therapy With Histone Deacetylase Inhibitors (HDACi) for the Treatment of Cancer: Achieving the Full Therapeutic Potential of HDACi

Genetic and epigenetic changes in DNA are involved in cancer development and tumor progression. Histone deacetylases (HDACs) are key regulators of gene expression that act as transcriptional repressors by removing acetyl groups from histones. HDACs are dysregulated in many cancers, making them a therapeutic target for the treatment of cancer. Histone deacetylase inhibitors (HDACi), a novel class of small-molecular therapeutics, are now approved by the Food and Drug Administration as anticancer agents. While they have shown great promise, resistance to HDACi is often observed and furthermore, HDACi have shown limited success in treating solid tumors. The combination of HDACi with standard chemotherapeutic drugs has demonstrated promising anticancer effects in both preclinical and clinical studies. In this review, we summarize the research thus far on HDACi in combination therapy, with other anticancer agents and their translation into preclinical and clinical studies. We additionally highlight the side effects associated with HDACi in cancer therapy and discuss potential biomarkers to either select or predict a patient's response to these agents, in order to limit the off-target toxicity associated with HDACi.