Platinum anti-cancer drugs: Free radical mechanism of Pt-DNA adduct formation and anti-neoplastic effect

Platinum iodido drugs show potential anti-tumor activity, affecting cancer cell metabolism and inducing ROS and senescence in gastrointestinal cancer cells

Cisplatin-based chemotherapy has associated clinical disadvantages, such as high toxicity and resistance. Thus, the development of new antitumor metallodrugs able to overcome different clinical barriers is a public healthcare priority. Here, we studied the mechanism of action of the isomers trans and cis-[PtI2(isopropylamine)2] (I5 and I6, respectively) against gastrointestinal cancer cells. We demonstrate that I5 and I6 modulate mitochondrial metabolism, decreasing OXPHOS activity and negatively affecting ATP-linked oxygen consumption rate. Consequently, I5 and I6 generated Reactive Oxygen Species (ROS), provoking oxidative damage and eventually the induction of senescence. Thus, herein we propose a loop with three interconnected processes modulated by these iodido agents: (i) mitochondrial dysfunction and metabolic disruptions; (ii) ROS generation and oxidative damage; and (iii) cellular senescence. Functionally, I5 reduces cancer cell clonogenicity and tumor growth in a pancreatic xenograft model without systemic toxicity, highlighting a potential anticancer complex that warrants additional pre-clinical studies.

Synthesis, anticancer activity, and molecular docking of half-sandwich iron(II) cyclopentadienyl complexes with maleimide and phosphine or phosphite ligands

In these studies, we designed and investigated the potential anticancer activity of five iron(II) cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All complexes were characterized with spectroscopic analysis viz. NMR, FT-IR, ESI-MS, UV-Vis, fluorescence, XRD (for four complexes) and elemental analyses. For biological studies, we used three types of cells-normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and non-small-cell lung cancer A549 cells. We evaluated cell viability and DNA damage after cell incubation with these complexes. We observed that all iron(II) complexes were more cytotoxic for HL-60 cells than for A549 cells. The complex CpFe(CO)(P(OPh)3)(η1-N-maleimidato) 3b was the most cytotoxic with IC50 = 9.09 µM in HL-60 cells, IC50 = 19.16 µM in A549 and IC50 = 5.80 µM in PBM cells. The complex CpFe(CO)(P(Fu)3)(η1-N-maleimidato) 2b was cytotoxic only for both cancer cell lines, with IC50 = 10.03 µM in HL-60 cells and IC50 = 73.54 µM in A549 cells. We also found the genotoxic potential of the complex 2b in both types of cancer cells. However, the complex CpFe(CO)2(η1-N-maleimidato) 1 which we studied previously, was much more genotoxic than complex 2b, especially for A549 cells. The plasmid relaxation assay showed that iron(II) complexes do not induce strand breaks in fully paired ds-DNA. The DNA titration experiment showed no intercalation of complex 2b into DNA. Molecular docking revealed however that complexes CpFe(CO)(PPh3) (η1-N-maleimidato) 2a, 2b, 3b and CpFe(CO)(P(OiPr)3)(η1-N-maleimidato) 3c have the greatest potential to bind to mismatched DNA. Our studies demonstrated that the iron(II) complex 1 and 2b are the most interesting compounds in terms of selective cytotoxic action against cancer cells. However, the cellular mechanism of their anticancer activity requires further research.

Oxidative Damage as a Fundament of Systemic Toxicities Induced by Cisplatin-The Crucial Limitation or Potential Therapeutic Target?

Cisplatin, an inorganic complex of platinum, is a chemotherapeutic drug that has been used for 45 years. Despite the progress of pharmaceutical sciences and medicine and the successful application of other platinum complexes for the same purpose, cisplatin is still the therapy of choice in many cancers. Treatment for testicular, ovarian, head and neck, urothelial, cervical, esophageal, breast, and pulmonary malignancies is still unthinkable without the use of this drug. However, cisplatin is also known for many side effects, of which the most pronounced are nephrotoxicity leading to acute renal failure, neurotoxicity, and ototoxicity. Mechanistic studies have proven that one of the conditions that plays a major role in the development of cisplatin-induced toxicities is oxidative stress. Knowing the fact that numerous antioxidants can be used to reduce oxidative stress, thereby reducing tissue lesions, organ failure, and apoptosis at the cellular level, many studies have defined antioxidants as a priority for investigation as a cotreatment. To investigate the mechanism of antioxidant action in vivo, many animal models have been employed. In the last few years, studies have mostly used rodents and zebrafish models. In this article, some of the most recent investigations that used animal models are listed, and the advantages and disadvantages of such experimental studies are pointed out.

Nose to brain delivery of naringin-loaded chitosan nanoparticles for potential use in oxaliplatin-induced chemobrain in rats: impact on oxidative stress, cGAS/STING and HMGB1/RAGE/TLR2/MYD88 inflammatory axes

OBJECTIVES

Oxaliplatin induces chemobrain in cancer patients/survivors. Nutraceutical naringin has antioxidant and anti-inflammatory properties with low oral bioavailability. Our aim was to formulate naringin in chitosan nanoparticles for nose to brain delivery and assess its neuroprotective effect against oxaliplatin-induced chemobrain in rats.

METHODS

Naringin chitosan nanoparticles were prepared by ionic gelation. Rats were administered oral naringin (80 mg/kg), intranasal naringin (0.3 mg/kg) or intranasal naringin-loaded chitosan nanoparticles (0.3 mg/kg). Naringin's neuroprotective efficacy was assessed based on behavioral tests, histopathology, and measuring oxidative stress and inflammatory markers.

RESULTS

Selected nanoparticles formulation showed drug loading of 5%, size of 150 nm and were cationic. Intranasal naringin administration enhanced memory function, inhibited hippocampal acetylcholinesterase activity, and corrected oxaliplatin-induced histological changes. Moreover, it reduced malondialdehyde and elevated reduced glutathione hippocampal levels. Furthermore, it decreased levels of inflammatory markers: NF-kB and TNF-α by 1.25-fold. Upstream to this inflammatory status, intranasal naringin downregulated the hippocampal protein levels of two pathways: cGAS/STING and HMGB1/RAGE/TLR2/MYD88.

CONCLUSION

Intranasal naringin-loaded chitosan nanoparticles showed superior amelioration of oxaliplatin-induced chemobrain in rats at a dose 267-fold lower to that administered orally. The potential involvement of cGAS/STING and HMGB1/RAGE/TLR2/MYD88 pathways in the mechanistic process of either oxaliplatin-induced chemobrain or naringin-mediated neuroprotection was evidenced.

Effect of cisplatin on respiratory activity in neonatal rats

One side effect of cisplatin, a cytotoxic platinum anticancer drug, is peripheral neuropathy; however, its central nervous system effects remain unclear. We monitored respiratory nerve activity from the C4 ventral root in brainstem and spinal cord preparations from neonatal rats (P0-3) to investigate its central effects. Bath application of 10-100 μM cisplatin for 15-20 min dose-dependently decreased the respiratory rate and increased the amplitude of C4 inspiratory activity. These effects were not reversed after washout. In separate perfusion experiments, cisplatin application to the medulla decreased the respiratory rate, and application to the spinal cord increased the C4 burst amplitude without changing the burst rate. Application of other platinum drugs, carboplatin or oxaliplatin, induced no change of respiratory activity. A membrane potential analysis of respiratory-related neurons in the rostral medulla showed that firing frequencies of action potentials in the burst phase tended to decrease during cisplatin application. In contrast, in inspiratory spinal motor neurons, cisplatin application increased the peak firing frequency of action potentials during the inspiratory burst phase. The increased burst amplitude and decreased respiratory frequency were partially antagonized by riluzole and picrotoxin, respectively. Taken together, cisplatin inhibited respiratory rhythm via medullary inhibitory system activation and enhanced inspiratory motor nerve activity by changing the firing property of motor neurons.

Recent Developments in the Study of the Microenvironment of Cancer and Drug Delivery

Cancer is characterized by disrupted molecular variables caused by cells that deviate from regular signal transduction. The uncontrolled segment of such cancerous cells annihilates most of the tissues that contact them. Gene therapy, immunotherapy, and nanotechnology advancements have resulted in novel strategies for anticancer drug delivery. Furthermore, diverse dispersion of nanoparticles in normal stroma cells adversely affects the healthy cells and disrupts the crosstalk of tumour stroma. It can contribute to cancer cell progression inhibition and, conversely, to acquired resistance, enabling cancer cell metastasis and proliferation. The tumour's microenvironment is critical in controlling the dispersion and physiological activities of nano-chemotherapeutics which is one of the targeted drug therapy. As it is one of the methods of treating cancer that involves the use of medications or other substances to specifically target and kill off certain subsets of malignant cells. A targeted therapy may be administered alone or in addition to more conventional methods of care like surgery, chemotherapy, or radiation treatment. The tumour microenvironment, stromatogenesis, barriers and advancement in the drug delivery system across tumour tissue are summarised in this review.

Prognostic role of pre-treatment serum ALB in Patients with oropharyngeal cancer: A retrospective cohort study

BACKGROUND

The morbidity of oropharyngeal cancer (OPC) is continuing to rise in numerous developed countries. An accurate prognostic assessment is needed to evaluate the malignant degree or risk classification to optimize treatment. Albumin (ALB) as an independent prognostic indicator of cancer survival has been established in previous studies. This study investigated the prognostic value of pre-treatment serum ALB in OPC patients.

METHODS

The clinicopathological data of 246 patients diagnosed with OPC from 2010 to 2019 were analyzed retrospectively. Analyze the relationship between ALB and clinicopathological characteristics of patients. The optimal cut-off values for ALB were determined via Cutoff Finder (Method for cutoff determination: Survival: significance (log-rank test)). To determine the independent prognostic factors, the Cox proportional hazards model was used to perform univariate and multivariate analyses of the serum ALB levels related to overall survival (OS) and disease-free survival (DFS).

RESULTS

The optimal cut-off point for ALB was 39.15 g/L determined via Cutoff Finder. Serum ALB levels were significantly associated with age (P=0.047), Presence of comorbidity (P=0.009), Charlson score index (P=0.007), Hemoglobin (P<0.001), Neutrophil to Lymphocyte Ratio (P=0.002), Albumin-To-Alkaline Phosphatase Ratio (P<0.001), Alkaline phosphatase (P=0.005), T stage (P=0.016), and HPV status (P=0.002). In the univariate and multivariate analyses, ALB was found to be an independent prognostic indicator for DFS (HR =0.39, 95% CI:0.23-0.66, P=0.000) and OS (HR =0.46, 95% CI: 0.25-0.83, P=0.01) in OPC patients.

CONCLUSIONS

Pre-treatment serum ALB could serve as a valuable prognostic biomarker for the prognostic stratification of OPC patients.

Deep-Penetrating Triple-Responsive Prodrug Nanosensitizer Actuates Efficient Chemoradiotherapy in Pancreatic Ductal Adenocarcinoma Models

Chemoradiotherapy (CRT) is the most accepted treatment for locally advanced pancreatic ductal adenocarcinoma (PDAC) and can significantly improve the R0 resection rate. However, there are few long-term survivors after CRT. Although some polymer nanoparticles have shown potential in alleviating the dose-limiting toxicity and assisting the chemotherapy of PDAC, there are few efficient nanosensitizers (NS) available for CRT of this malignancy, especially in the context of its hypoxic nature. Herein, based on the biological features of PDAC, a γ-glutamyl transpeptidase (GGT)/glutathione (GSH)/hypoxia triple-responsive prodrug NS to overcome the biological barrier and microenvironmental limitations confronted by CRT in PDAC is developed. Due to triple-responsiveness, deep tumor penetration, GSH/hypoxia-responsive drug release/activation, and hypoxia-induced chemoradio-sensitization can be simultaneously achieved with this NS. As a result, tumor shrinkage after CRT with this NS can be observed in both subcutaneous and orthotopic PDAC models, foreshadowing its potential in clinical neoadjuvant CRT.

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides as Novel Potential Anticancer Agents: Cytotoxic and Genotoxic Activities In Vitro

In this paper, we present for the first time the evaluation of cytotoxicity and genotoxicity of de novo synthesized pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides MM129, MM130, and MM131 in human tumor cell lines: HeLa, HCT 116, PC-3, and BxPC-3. Cytotoxic and genotoxic properties of the tested compounds were estimated using the MTT assay, comet assay (alkaline and neutral version), and γ-H2AX immuno-staining. Examined sulfonamides exhibited strong anticancer properties towards tested cells in a very low concentration range (IC₅₀ = 0.17-1.15 μM) after 72 h exposure time. The results of the alkaline and neutral version of the comet assay following 24 h incubation of the cells with tested compounds demonstrated the capability of heterocycles to induce significant DNA damage in exposed cells. HCT 116 cells were the most sensitive to the genotoxic activity of novel tricyclic pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides in the neutral version of the comet assay. Immunocytochemical detection of γ-H2AX showed an increase in DNA DSBs level in the HCT 116 cell line, after 24 h incubation with all tested compounds, confirming the results obtained in the neutral comet assay. Among all investigated compounds, MM131 showed the strongest cytotoxic and genotoxic activity toward all tested cell types. In conclusion, our results suggest that MM129, MM130, and MM131 exhibit high cytotoxic and genotoxic potential in vitro, especially towards the colorectal cancer cell line HCT 116. However, further investigations and analyses are required for their future implementation in the field of medicine.

Synthesis, Crystal Structure, and Hirshfeld Surface Analysis of Hexachloroplatinate and Tetraclorouranylate of 3-Carboxypyridinium—Halogen Bonds and π-Interactions vs. Hydrogen Bonds

This work aimed to synthesize new platinum and uranium compounds with nicotinic acid. In this article we describe the synthesis of two new anionic complexes (HNic)2[PtCl6] and (HNic)2[UO2Cl4] using wet chemistry methods. The structure of the obtained single crystals was established by single-crystal X-ray diffraction. The Hirshfeld surface analysis of the obtained complexes and their analogue (HNic)2[SiF6] was carried out for the analysis of intermolecular interactions. Hydrogen bonds (H···Hal/Hal···H and O···H/H···O) make the main contribution to intermolecular interactions in all compounds. Other important contacts in cations in all compounds are H···H, C···H/H···C and C···Hal/Hal···C; in anions H···Hal/Hal···H. The Pt-containing complex has a halogen-π interaction and halogen bonds, but Si-containing complex has a π–π staking interaction; these types of interactions are not observed in the U-containing compound.

The influence of acute kidney disease on the clinical outcomes of patients who received cisplatin, carboplatin, and oxaliplatin

Background and Aims

Cisplatin (CDDP) is used as the first line of treatment for some tumors, but its use may be restricted due to its nephrotoxicity. Carboplatin (CARBO) and oxaliplatin (OXA) are less nephrotoxic alternatives to CDDP. This study has the objective to determine the incidence of acute kidney disease after chemotherapy with CDDP, CARBO, or OXA.

Methods

A clinical study of a retrospective cohort of patients who underwent treatment with CDDP, CARBO, or OXA from January‐December 2016. Acute kidney Disease (AKD) was defined as elevated serum creatinine (sCR) levels before and up to 3 months after chemotherapy. Morbidities, type of tumor, and treatment data were recorded.

Results

A total of 212 patients aged 55.5 ± 14.0 years were evaluated. Among the comorbidities, 30% had arterial hypertension (AH) and 11% had diabetes, and 18% were treated with CDDP, 41% with CARBO, and 41% with OXA. There was no difference in sCR levels before and after chemotherapy regardless of the chemotherapy used. The prevalence of eGFRs <60 mL/min after chemotherapy was higher in patients with AH and cardiovascular disease (CVD). The incidence of post‐chemotherapy AKD was 7.0% (n = 13) and the mortality rate was 38.2%. Survival was lower in patients with AKD (P = .012).

Conclusions

There was a low incidence of AKD among the patients regardless of the chemotherapy used, but the patients with AKD had shorter survival. In addition, the reduction in eGFR after chemotherapy was greater in patients with AH and CVD.

Comparative NMR metabolomics of the responses of A2780 human ovarian cancer cells to clinically established Pt-based drugs

Pt-based drugs play a very important role in current cancer treatments; yet, their cellular and mechanistic aspects are not fully understood. NMR metabolomics provides a powerful tool to investigate the...

Antiproliferative, antimigratory, and prooxidative potential of novel platinum(IV) complexes and resveratrol on breast cancer (MDA-MB-231) and choriocarcinoma (JEG-3) cell lines

Platinum(IV) complexes offer the potential to overcome cisplatin resistance of cancer cells, with possible improved selectivity. Resveratrol, a natural polyphenol with anticancer and antioxidant capacity, could limit the possible side effects of chemotherapeutics on healthy cells. This study investigates the effects of platinum(IV) complexes containing some esters of the ethylenediamine-N,N'-di-S,S-(2,2'-dibenzyl)acetate acid (H₂ -S,S-eddba), and resveratrol on proliferation, migration, and redox balance of breast cancer (MDA-MB-231), choriocarcinoma (JEG-3), and human lung fibroblast (MRC-5) cell line. According to IC₅₀ values, all complexes exhibited a significantly stronger antiproliferative effect on tested cell lines compared to cisplatin. Due to reduced adverse effects on MRC-5 cells, the complex containing ethyl-substituent (10 μM) was selected for further examination with resveratrol (25 μM) cotreatment. Resveratrol enhanced the survival of MRC-5 cells while diminished the viability of both used cancer cell lines when applied combined with selected complex. Furthermore, cotreatment of these two compounds decreased the migratory potential of tested cancer cell lines. The examined platinum(IV) complex was able to induce oxidative stress in all tested cell lines. Resveratrol proved to be efficient in protecting MRC-5 cells from complex-induced oxidative damage, while it significantly amplified antiproliferative, antimigratory, and prooxidative effects of platinum(IV) complex on both examined cancer cell lines. These findings may be valuable in elucidating the mechanism of action of platinum(IV) drugs, which should be further investigated.

Half-lantern Cyclometalated Platinum(II) Complexes as Anticancer Agents: Molecular docking, Apoptosis, Cell Cycle Analysis and Cytotoxic Activity Evaluations

BACKGROUND AND OBJECTIVE

In the design of modern metal-based anticancer drugs, platinum-based complexes have gained growing interest. In this study, the anticancer activity of half-lantern cyclometalated Pt(II)‒Pt(II) complexes were was evaluated using MTT, apoptosis, cell cycle analysis, and DNA binding studies.

MATERIALS AND METHODS

The cytotoxicity of Pt(II)‒Pt(II) complexes were evaluated against different cancer cell lines such as human lung (A549), breast (MCF-7, and MDA-MB-231), ovarian (SKOV-3), and colon (HT-29) as well as normal breast (MCF-10A), and human lung fibroblast MRC-5 cells using MTT assay. BioLegend's PE Annexin V Apoptosis Detection Kit with 7AAD was applied to assess the apoptotic effects of 1A, and 1B compound against MCF-7, and A549 cell lines. Cell cycle analysis was determined using the flowcytometry method. The interaction of compounds with four different DNA structures with PDB codes (1BNA, 1LU5, 3CO3, and 198D) has been investigated by molecular docking. To achieve binding to DNA experimentally, the electrophoresis mobility shift assay and comet assay was applied.

RESULTS

In the evaluation of cytotoxic effects, 1A showed the highest cytotoxicity among the studied compounds, and it showed higher potency with more selectivity against normal cell lines than cisplatin. This compound had IC50 of 7.24, 2.21, 1.18, 2.71, 10.65, 18.32 and 49.21 μM against A549, SKOV3, HT29, MCF-7, MDA-MB-231, MRC-5, and MCF-10A, respectively, whereas cisplatin had IC50 of 9.75, 19.02, 107.23, 15.20, 18.09, 14.36, and 24.21 μm, respectively, on the same cell lines. In order to check the DNA binding activity of 1A, and 1B, electrophoretic mobility was also conducted, which indicated that the binding of these compounds led to a slight change in electrophoretic mobility to DNA. The migration of chromosomal DNA from the nucleus in the form of a tail or comet was executed in the comet assay of 1A on MCF-7. Examination of apoptosis of 1A, and 1B on the MCF-7 cancer cell line, showed that it could increase induction of apoptosis in this cancerous cell in a concentration-dependent manner. Investigating the effect of 1A using cell cycle analysis on MCF-7 cancer cell line showed that this complex affects the stage G1 and S of the cell cycle.

CONCLUSION

1A has the potential to play a significant role in future biopharmaceutical studies.

ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in patients with ovarian cancer: a systematic review and meta-analysis

OBJECTIVE

To explore the relationship between ERCC1 rs11615 polymorphism and chemosensitivity to platinum drugs in ovarian cancer by the method of meta-analysis.

METHODS

Pubmed, Web of Science, EMBASE, Cochrane Library, China National Knowledge Infrastructure (CNKI), and China Wanfang databases were comprehensively searched up to September 2020, to identify the relationship between ERCC1 rs11615 polymorphism and chemosensitivity of ovarian cancer. The data was analyzed by Stata 15.0 statistic software.

RESULTS

A total of 10 published papers were included, including 1866 patients with ovarian cancer. The results showed that compared allele C at ERCC1 rs11615 locus with allele T, the pooled OR was 0.92 (95%CI:0.68 ~ 1.24, P > 0.05). There were no significant differences in recessive, dominant, homozygous, and heterozygous models. In accordance with a subgroup analysis of Ethnicity, all genotypes were statistically significant in the Asian population. In the allelic, dominant, recessive, homozygous and heterozygous models, the OR was 0.70 (95%CI:0.51 ~ 0.95), 0.20 (95%CI:0.07 ~ 0.56), 0.79 (95%CI:0.63 ~ 1.00), 0.21 (95%CI:0.07 ~ 0.59), 0.19 (95%CI:0.07 ~ 0.54), respectively, while in the Caucasian population, no statistically significant genotype was found.

CONCLUSION

The ERCC1 rs11615 polymorphism is associated with chemosensitivity in patients with ovarian cancer, especially in the Asian population, but not in the Caucasian population.

Aptamer and Peptide-Modified Lipid-Based Drug Delivery Systems in Application of Combined Sequential Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is known as the most common malignancy of the hepatobiliary system with a continued increase in incidence but limited therapeutic options. Nanomedicine has provided a promising strategy through engineered nanocarriers that are capable of targeting therapeutic agents specifically to tumor cells. In this research, two aptamer/peptide-modified lipid-based drug delivery systems (A54-PEG-SLN/OXA and A15-PEG-SLN/SAL) were developed as a sequential therapeutic strategy to conquer specific hepatocellular carcinoma. The nanomedicine A54-PEG-SLN/OXA was able to target specific hepatocellular carcinoma cell BEL-7402 and exhibited a strong targeting ability and antitumor efficiency both in vitro and in vivo. The A15-PEG-SLN/SAL could target and penetrate deeply to the spheroid composed of CD133+ cancer cells. In the study of developing a sequential therapeutic strategy, we demonstrated that A54-PEG-SLN/OXA could kill tumor cells and expose CD133+ cancer cells. After the administration of A15-PEG-SLN/SAL, the growth of the tumors was significantly inhibited. In conclusion, the aptamer/peptide-modified lipid-based drug delivery systems, A54-PEG-SLN/OXA and A15-PEG-SLN/SAL, could specifically target carcinoma cells and had an evident antitumor effect when administrated sequentially.

The Impact of Platinum-Containing Chemotherapies in Advanced Triple-Negative Breast Cancer: Meta-Analytical Approach to Evaluating Its Efficacy and Safety

BACKGROUND

Triple-negative breast cancer (TNBC), the most common type of breast cancer, is associated with poor patient prognosis. Platinum-containing chemotherapies are commonly used in the treatment and prevention of advanced TNBC.

OBJECTIVES AND METHODS

To systematically evaluate the effectiveness and safety of platinum-containing chemotherapies in patients with advanced TNBC, we searched several databases, including PubMed, Medline, Embase, ClinicalTrials.gov, Cochrane Library, CNKI, CBM, and the Chinese Cochrane Center, to collect published randomized controlled clinical studies of platinum-containing chemotherapies for advanced TNBC before November 2020. The meta-analysis was performed using Review Manager version 5.3. To assess effectiveness and safety, dichotomous and continuous variables were assessed using odds ratio (OR) and mean difference (MD), respectively, with 95% CI.

RESULTS

A total of 1,222 patients with advanced TNBC were enrolled in 11 eligible trials, including 489 patients in the treatment group (platinum-containing) and 447 patients in the control group (non-platinum-containing). We also retrieved information whether a PARP inhibitor was combined with platinum-containing chemotherapy for patients with metastatic TNBC and identified 224 patients who received a PARP inhibitor combined with platinum-containing chemotherapy and 62 patients in the platinum-containing group who did not. The platinum-containing chemotherapy group had a significantly better objective response rate (OR 1.43, 95% CI 1.20-1.71, p < 0.001) and longer progression-free survival (PFS; MD 1.15, 95% CI 0.03-2.28, p < 0.05) than the non-platinum-containing chemotherapy group. However, there was no significant difference in overall survival (OS) of patients with advanced TNBC between the two groups (MD 2.04, 95% CI -0.83 to 4.91, p > 0.05). Related adverse effects of platinum-containing chemotherapies involved gastrointestinal reaction, myelosuppression and liver function damage. Platinum-containing chemotherapies were not associated with an increased incidence of adverse side effects compared with non-platinum-containing chemotherapies, with the exception of nausea and vomiting (OR 2.22, 95% CI 1.10-4.46, p < 0.05). Furthermore, the addition of the PARP inhibitor iniparib to gemcitabine and carboplatin treatment improved the rate of clinical benefit, OS and PFS.

CONCLUSIONS

Platinum-containing chemotherapy remains a highly recommended therapeutic regimen due to greater effectiveness and tolerance for patients with advanced TNBC.

Protective effect of chrysin, a flavonoid, on the genotoxic activity of carboplatin in mice

Carboplatin is amongst the most commonly used anticancer drugs for the management of several human malignancies. However, it has displayed genotoxic properties against normal cells. Evaluation of natural products for their protective effects against chemotherapeutic drug induced toxicity has been growing in recent years. A naturally occurring flavonoid, chrysin, has strong antioxidant abilities and protects against DNA impairment. This study used multiple assays to evaluate the levels of damage to DNA in normal cells and to examine any possible protective role of chrysin against such damage. Male BALB/c mice were administered chrysin orally in two doses of 20 and 40 mg/kg for 10 consecutive days and then a single injection of carboplatin [90 mg/kg body weight (b.w.)] was administered intraperitoneally to induce carboplatin toxicity. 24 h after the carboplatin injection, mice were sacrificed. DNA damage was evaluated using several genotoxicity tests (8-Hydroxydeoxy-guanosine marker, comet assay, micronucleus test, and chromosomal aberration assay) to identify diverse types of damage to the DNA. The results suggest that pretreatment with chrysin significantly decreased the level of DNA damage caused by carboplatin probably due to its potent antioxidant traits. Therefore, chrysin can be considered to be developed as a chemoprotective agent against chemotherapy associated side-effects.

Cisplatin resistance reversal in lung cancer by tumor acidity-activable vesicular nanoreactors via tumor oxidative stress amplification

Drug resistance of cisplatin significantly limits its therapeutic efficacy in clinical applications against different cancers. Herein, we develop a novel strategy to overcome cisplatin drug resistance through sensitizing cisplatin-resistant human lung cancer cells (A549R) under amplified oxidative stress using a vesicular nanoreactor for simultaneous cisplatin delivery and H₂O₂ generation. We engineer the nanoreactor by the self-assembly of the amphiphilic diblock copolymers to co-deliver glucose oxidase (GOD) and cisplatin (Cis) (Cis/GOD@Bz-V). Cis/GOD@Bz-V was rationally designed to stay impermeable during blood circulation while mild acidity (pH 6.5-6.8) can activate its molecular-weight selective membrane permeability and release cisplatin locally. Diffusion of small molecules such as oxygen and glucose across the membranes can induce the in situ generation of superfluous H₂O₂ to promote cellular oxidative stress and sensitize A549R cells via activation of pro-apoptotic pathways. Cis/GOD@Bz-V nanoreactors could effectively kill A549R at pH 6.8 in the presence of glucose by the combination of H₂O₂ generation and cisplatin release. Growth of A549R xenograft tumors can be inhibited efficiently without the obvious toxic side effects via the systemic administration of Cis/GOD@Bz-V. Accordingly, the tumor acidity-activable cisplatin-loaded nanoreactors show great potential to enhance the therapeutic efficacy against cisplatin-resistant cancers.

Evaluation of Toxic Effects of Novel Platinum (IV) Complexes in Female Rat Liver: Potential Protective Role of Resveratrol

The use of cisplatin in chemotherapy may provoke a deteriorating impact in many vital organs, suggesting the need for more selective derivatives and effective protective cotreatments. This study assesses the effects of three novel Pt(IV) complexes containing ethyl-, propyl- and butyl-esters of the ethylenediamine-N, N'-di-S, S- (2,2'-dibenzyl) acetic acid on liver injury markers, redox parameters, and cell morphology of female rat liver tissue in comparison to cisplatin. In addition, the study evaluates the possible protective effects of resveratrol as well. The rats were divided into ten groups and were administered intraperitoneally with a single dose of cisplatin (7.5 mg/kg) or Pt(IV) complexes (10 mg/kg) and/or resveratrol (25 mg/kg). All treatments caused changes in body weight, food intake, and liver/bw ratio. Acute treatment with novel complexes decreased the levels of TB and TP while elevated the activity of ALT, AST, GGT, ALP which subsequently indicated on the liver damage. All three complexes significantly reduced the levels of LPO, O₂^.-, NO₂^- and activity of CAT, while increasing the activity of SOD, GSH-Px, GR, GST, and level of GSH, implying that these compounds could provoke redox balance disruption in liver cells. Moreover, according to the histopathological observations, the novel Pt(IV) complexes exerted stronger hepatotoxicity than cisplatin. Possible protective effects of resveratrol were not detected and even combined with examined compounds it abolished the activity of the antioxidative system of the liver cells causing more intense toxicity. Further investigation is required to elucidate the effects of Pt-based drugs and resveratrol in the estradiol-rich environment of female rats as well their influence on male rats' tissues.

Role of CC Chemokines Subfamily in the Platinum Drugs Resistance Promotion in Cancer

Cancer is a significant medical issue, being one of the main causes of mortality around the world. The therapies for this pathology depend on the stage in which the cancer is found, but it is usually diagnosed at an advanced stage in which the treatment is chemotherapy. Platinum drugs are among the most commonly used in therapy, unfortunately, one of the main obstacles to this treatment is the development of chemoresistance, which is the ability of cancer cells to evade the effects of drugs. Although some molecular mechanisms involved in resistance to platinum drugs are described, elucidation is still required of others. Secretion of inflammatory mediators such as cytokines and chemokines, by tumor microenvironment components or tumor cells, show direct influence on proliferation, metastasis and progression of cancer and are related to chemoresistance and poor prognosis. In this review, the general mechanisms associated with resistance to platinum drugs, inflammation on cancer development and chemoresistance in various types of cancer will be approached with special emphasis on the current history of CC chemokines subfamily-mediated chemoresistance.

Advances in the Application of Liposomal Nanosystems in Anticancer Therapy

Cancer is the disease with the highest mortality rate, which poses a great threat to people's lives. Cancer caused approximately 3.4 million death worldwide annually. Surgery, chemotherapy and radiotherapy are the main therapeutic methods in clinical practice. However, surgery is only suitable for patients with early-stage cancers, and chemotherapy as well as radiotherapy have various side effects, both of which limit the application of available therapeutic methods. In 1965, liposome was firstly developed to form new drug delivery systems given the unique properties of nanoparticles, such as enhanced permeability and retention effect. During the last 5 decades, liposome has been widely used for the purpose of anticancer drug delivery, and several advances have been made regarding liposomal technology, including long-circulating liposomes, active targeting liposomes and triggered release liposomes, while problems exist all along. This review introduced the advances as well as the problems during the development of liposomal nanosystems for cancer therapy in recent years.

Mechanisms of different response to ionizing irradiation in isogenic head and neck cancer cell lines

Background

Treatment options for recurrent head and neck tumours in the previously irradiated area are limited, including re-irradiation due to radioresistance of the recurrent tumour and previous dose received by surrounding normal tissues. As an in vitro model to study radioresistance mechanisms, isogenic cells with different radiosensitivity can be used. However, they are not readily available. Therefore, our objective was to establish and characterize radioresistant isogenic human pharyngeal squamous carcinoma cells and to evaluate early radiation response in isogenic parental, radioresistant and radiosensitive cells.

Methods

Radioresistant cells were derived from parental FaDu cells by repeated exposure to ionizing radiation. Radiosensitivity of the established isogenic radioresistant FaDu-RR cells was evaluated by clonogenic assay and compared to isogenic parental FaDu and radiosensitive 2A3 cells. Additional phenotypic characterization of these isogenic cells with different radiosensitivity included evaluation of chemosensitivity, cell proliferation, cell cycle, radiation-induced apoptosis, resolution of DNA double-strand breaks, and DNA damage and repair signalling gene expression before and after irradiation.

Results

In the newly established radioresistant cells in response to 5 Gy irradiation, we observed no alteration in cell cycle regulation, but delayed induction and enhanced resolution of DNA double-strand breaks, lower induction of apoptosis, and pronounced over-expression of DNA damage signalling genes in comparison to parental cells. On the other hand, radiosensitive 2A3 cells were arrested in G₂/M-phase in response to 5 Gy irradiation, had a prominent accumulation of and slower resolution of DNA double-strand breaks, and no change in DNA damage signalling genes expression.

Conclusions

We concluded that the emergence of the radioresistance in the established radioresistant isogenic cells can be at least partially attributed to the enhanced DNA double-strand break repair, altered expression of DNA damage signalling and repair genes. On the other hand, in radiosensitive isogenic cells the reduced ability to repair a high number of induced DNA double-strand breaks and no transcriptional response in DNA damage signalling genes indicate on a lack of adaptive response to irradiation. Altogether, our results confirmed that these isogenic cells with different radiosensitivity are an appropriate model to study the mechanisms of radioresistance.

The Protective Effect of Naringenin on Oxaliplatin-Induced Genotoxicity in Mice

Oxaliplatin is a third generation platinum based anti-cancer drug used against various human malignancies but displays genotoxic properties against normal cells. Naringenin is a naturally occurring bioflavonoid that possesses anti-oxidant properties and has protective effects against DNA damage. The aim of this study is to examine the protective effects of naringenin on oxaliplatin-induced DNA damage in mice. A total of 50, male BALB/c mice were randomly divided equally into five groups. Oxaliplatin toxicity was induced by a single dose (7 mg/kg body weight (b.w.)) injection (intraperitoneally (i.p.)) of oxaliplatin. Naringenin was given orally for ten consecutive days at two doses, 20 mg/kg b.w. (dose I) and 40 mg/kg b.w. (dose II), to group I and group II, respectively. On the tenth day of the experiment, animals in groups III, IV, and V were given a single i.p. injection of oxaliplatin (7 mg/kg b.w.). All the animals were sacrificed 24 h after oxaliplatin treatment. The extent of genotoxicity was assessed by multiple genotoxicity assays (8-hydroxydeoxy-guanosine marker, comet, micronucleus and chromosomal aberration assays, oxidative stress-marker Glutathione evaluation) in order to determine diverse kinds of DNA damage. The results indicated that naringenin administration significantly reduced the DNA damage induced by oxaliplatin possibly due to its strong anti-oxidant properties. The results suggest that naringenin is a potential candidate for future development as a chemoprotective agent against chemotherapy associated complications.

Molecular markers of DNA damage and repair in cervical cancer patients treated with cisplatin neoadjuvant chemotherapy: an exploratory study

Neoadjuvant (or induction) chemotherapy can be used for cervical cancer patients with locally advanced disease; this treatment is followed by radical surgery and/or radiation therapy. Cisplatin is considered to be the most active platinum agent drug for this cancer, with a response rate of 20%. In order to understand how the cisplatin treatment affects the stress response, in this work, we performed an exploratory study to analyze a number of stress proteins before and after cisplatin neoadjuvant chemotherapy. The study involved 14 patients; the pre- and post-chemotherapy paired biopsies were examined by hematoxylin and eosin staining and by immunohistochemistry. The proteins evaluated were p53, P16/INK4A, MSH2, nuclear protein transcriptional regulator 1 (NUPR1), and HSPB1 (total: HSPB1/t and phosphorylated: HSPB1/p). These proteins were selected because there is previous evidence of their relationship with drug resistance. The formation of platinum-DNA adducts was also studied. There was a great variation in the expression levels of the mentioned proteins in the pre-chemotherapy biopsies. After chemotherapy, p53 was not significantly affected by cisplatin, as well as P16/INK4A and MSH2 while nuclear NUPR1 content tended to decrease (p = 0.056). Cytoplasmic HSPB1/t expression levels decreased significantly following cisplatin therapy while nuclear HSPB1/t and HSPB1/p tended to increase. Since the most significant changes following chemotherapy appeared in the HSPB1 expression levels, the changes were confirmed by Western blot. The platinum-DNA adducts were observed in HeLa cell in apoptosis; however, in the tumor samples, the platinum-DNA adducts were observed in morphologically healthy tumor cells; these cells displayed nuclear HSPB1/p. Further mechanistic studies should be performed to reveal how HSPB1/p is related with drug resistance. When the correlations of the markers with the response to neoadjuvant chemotherapy were examined, only high pre-chemotherapy levels of cytoplasmic HSPB1/p correlated with a poor clinical and pathological response to neoadjuvant cisplatin chemotherapy (p = 0.056) suggesting that this marker could be useful opening its study in a larger number of cases.

MicroRNA-31 Regulates Chemosensitivity in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is associated with an extremely poor prognosis, and most patients initially are or rapidly become unresponsive to platinum-based chemotherapy. MicroRNA-31 (miR-31) is encoded on a genomic fragile site, 9p21.3, which is reportedly lost in many MPM tumors. Based on previous findings in a variety of other cancers, we hypothesized that miR-31 alters chemosensitivity and that miR-31 reconstitution may influence sensitivity to chemotherapeutics in MPM. Reintroduction of miR-31 into miR-31 null NCI-H2452 cells significantly enhanced clonogenic resistance to cisplatin and carboplatin. Although miR-31 re-expression increased chemoresistance, paradoxically, a higher relative intracellular accumulation of platinum was detected. This was coupled to a significantly decreased intranuclear concentration of platinum. Linked with a downregulation of OCT1, a bipotential transcriptional regulator with multiple miR-31 target binding sites, we subsequently identified an indirect miR-31-mediated upregulation of ABCB9, a transporter associated with drug accumulation in lysosomes, and increased uptake of platinum to lysosomes. However, when overexpressed directly, ABCB9 promoted cellular chemosensitivity, suggesting that miR-31 promotes chemoresistance largely via an ABCB9-independent mechanism. Overall, our data suggest that miR-31 loss from MPM tumors promotes chemosensitivity and may be prognostically beneficial in the context of therapeutic sensitivity.

Agrimonolide and Desmethylagrimonolide Induced HO-1 Expression in HepG2 Cells through Nrf2-Transduction and p38 Inactivation

Agrimonolide and desmethylagrimonolide are the main bioactive polyphenols in agrimony with well-documented antioxidant, anti-diabetic, and anti-inflammatory potential. We report here for the first time that agrimonolide and desmethylagrimonolide stimulate the expression of phase II detoxifying enzymes through the Nrf2-dependent signaling pathway. Agrimonolide and desmethylagrimonolide also possess considerable protective activity from oxidative DNA damage. In order to explore the cytoprotective potential of agrimonolide and desmethylagrimonolide on oxidative stress in liver, we developed an oxidative stress model in HepG2 cells, and check the hypothesis whether Nrf2 pathway is involved. Western blotting and luciferase assay revealed that exposure of HepG2 cells to agrimonolide or desmethylagrimonolide leads to increased heme oxygenase-1 (HO-1) expression by activating ARE through induction of Nrf2 and suppression of Kelch-like ECH-associated protein 1 (Keap1). Moreover, agrimonolide and desmethylagrimonolide also activated ERK signaling pathways and significantly attenuated individual p38 MAPK expression, subsequently leading to Nrf2 nuclear translocation. In conclusion, our results indicated that transcriptional activation of Nrf2/ARE is critical in agrimonolide and desmethylagrimonolide-mediated HO-1 induction, which can be regulated partially by the blockade of p38 MAPK signaling pathway and inhibiting nuclear translocation of Nrf2.

Elevated exhalation of hydrogen peroxide in patients with non-small cell lung cancer is not affected by chemotherapy

OBJECTIVES

Reactive oxygen species, which are implicated in the process of carcinogenesis, are also responsible for cell death during chemotherapy (CHT). Therefore, the aim of the study was to evaluate exhaled H₂O₂ levels in non-small cell lung cancer (NSCLC) patients before and after CHT.

METHODS

Thirty patients (age 61.3 ± 9.3 years) with advanced NSCLC (stage IIIB-IV) and 15 age-matched healthy cigarette smokers were enrolled into the study. Patients received four cycles of cisplatin or carboplatin with vinorelbine every three weeks. Before and after the first, second, and fourth cycle, the concentration of H₂O₂ in exhaled breath condensate was measured with respect to treatment response.

RESULTS

At the baseline, NSCLC patients exhaled 3.8 times more H₂O₂ than the control group (0.49 ± 0.14 vs. 0.13 ± 0.03 µmol/L, P < 0.05); this difference persisted throughout the study. CHT had no noticeable effect on exhaled H₂O₂ levels independent of the treatment response (partial remission vs. progressive disease). Pre- and post-CHT cycles of H₂O₂ levels generally correlated positively.

DISCUSSION

The study demonstrated the occurrence of oxidative stress in the airways of advanced NSCLC patients. Exhaled H₂O₂ level was not affected by CHT and independent of treatment results and changes in the number of circulating neutrophils.