Insights Into the Role of Epigenetic Factors Determining the Estrogen Response in Estrogen-Positive Ovarian Cancer and Prospects of Combining Epi-Drugs With Endocrine Therapy.

Ovarian cancer is one of the most lethal malignancies. The population at the risk is continually on the rise due to the acquired drug resistance, high relapse rate, incomplete knowledge of the etiology, cross-talk with other gynecological malignancies, and diagnosis at an advanced stage. Most ovarian tumors are thought to arise in surface epithelium somehow in response to changes in the hormonal environment. Prolonged treatment with hormone replacement therapy (HRT) is also considered a contributing factor. Estrogens influence the etiology and progression of the endocrine/hormone-responsive cancers in a patient-specific manner. The concept of hormonal manipulations got attention during the last half of the 20th century when tamoxifen was approved by the FDA as the first selective estrogen receptor modulator (SERM). Endocrine therapy that has been found to be effective against breast cancer can be an option for ovarian cancer. It is now established that global changes in the epigenetic landscape are not only the hallmark of tumor development but also contribute to the development of resistance to hormone therapy. A set of functionally related genes involved in epigenetic reprogramming are controlled by specific transcription factors (TFs). Thus, the activities of TFs mediate important mechanisms through which epigenetic enzymes and co-factors modify chromatin for the worst outcome in a site-specific manner. Furthermore, the role of epigenetic aberrations involving histone modifications is established in ovarian cancer pathogenesis. This review aims to provide insights on the role of key epigenetic determinants of response as well as resistance to the hormone therapy, the current status of research along with its limitations, and future prospects of epigenetic agents as biomarkers in early diagnosis, prognosis, and personalized treatment strategies. Finally, the possibility of small phytoestrogenic molecules in combination with immunotherapy and epi-drugs targeting ovarian cancer has been discussed.

Promising Anticancer Activity of [Bis(1,8-quinolato)palladium (II)] Alone and in Combination.

Due to similar coordination chemistry of palladium and platinum, a large number of palladium compounds as well have been investigated for their anticancer activity. In the present study, we describe synthesis, characterization, and anticancer activity of palladium complex [Bis(1,8-quinolato)palladium (II)], coded as NH3 against seven different cancer cell lines. NH3 is found to have higher antitumor activity than cisplatin against both parent ovarian A2780 cell line and cisplatin-resistant cell lines. Also, NH3 has the lower IC50 value in HT-29 colorectal cancer cell line. The higher antitumor activity of NH3 is due to the presence of bulky 8-Hydroxyquinoline ligand, thus reducing its reactivity. Proteomic study has identified significantly expressed proteins which have been validated through bioinformatics. NH3 has been found to be less toxic than cisplatin at 2.5 mg/kg and 5 mg/kg dosages on mice models. Binary combinations of NH3 with curcumin and epigallocatechin gallate (EGCG) have demonstrated dose and sequence-dependent synergism in ovarian and colorectal cancer models. All of the preclinical studies indicate promising therapeutic potential of NH3 [Bis(1,8-quinolato)palladium (II)] as an anticancer drug.

Enhanced Accumulation of Cisplatin in Ovarian Cancer Cells from Combination with Wedelolactone and Resulting Inhibition of Multiple Epigenetic Drivers.

PURPOSE: Cisplatin resistance is a major concern in ovarian cancer treatment. The aim of this study was to investigate if wedelolactone could perform better in resistant ovarian cancer cells when used in combination with cisplatin. METHODS: Growth inhibitory potential of wedelolactone and cisplatin was investigated through MTT reduction assay in ovarian cancer cell lines including A2780 (sensitive), A2780cisR (cisplatin resistant) and A2780ZD0473R. Resistance factor (RF) of drugs was determined in these three cell lines. Combination index (CI) was calculated as a measure of combined drug action. Effect of this combination on changes in the cellular accumulation of platinum levels and platinum-DNA binding was also determined in vitro using AutoDock Vina while the effect of wedelolactone on inhibition of possible key culprits of resistance including Chk1, CD73, AT tip60, Nrf2, Brd1, PCAF, IGF1, mTOR1 and HIF2α was investigated in silico. RESULTS: Cisplatin and wedelolactone showed a dose-dependent growth inhibitory effect. RF value of wedelolactone was 1.1 in the case of A2780cisR showing its potential to bring more cell death in cisplatin-resistant cells. CI values were found to vary showing antagonistic to additive outcomes. Additive effect was observed for all sequences of administration (0/0, 0/4 and 4/0 h) in A2780cisR. Enhanced cellular accumulation of cisplatin was observed in parent and resistant cells on combination. Docking results revealed that among the selected oncotargets, Chk1, CD73, Nrf2, PCAF and AT tip60 were more vulnerable to wedelolactone than their respective standard inhibitors. CONCLUSION: These findings have shown that additive outcome of drug combination in A2780cisR and raised levels of platinum accumulation followed a clear pattern. This observation indicates that the presence of wedelolactone might have contributed to sensitize A2780cisR. However, in silico results point to the possible effects of this compound on epigenetic factors involving tumor microenvironment, epithelial mesenchymal transition, and immune-checkpoint kinases.

Synergistic Cytotoxic Effect from Combination of Wedelolactone and Cisplatin in HeLa Cell Line: A Novel Finding.

CONTEXT AND OBJECTIVE: Cisplatin is a platinum drug in current clinical use for the treatment of cervical cancer. However, drug toxicity and resistance are its two major limitations. The aim of this investigation was to test the cytotoxic activity of potential phytochemicals alone and in combination with cisplatin in cervical cancer cells. METHODS: In this study, cytotoxicity of phytochemicals including wedelolactone (WDL), betulinic acid (BA) and epigallocatechin gallate (EGCG) was investigated in human cervical cancer cell line HeLa through 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) reduction assay. Combined drug action resulting from the combination of cisplatin with WDL and BA was investigated in the same cell line through median effect principle. The combination index (CI) was taken as a measure of combined drug action. RESULTS: BA resulted in synergistic outcome when co-administered with cisplatin at 0/0 time; (bolus administration) while administration of either drug (cisplatin or BA) four hours before the other (0/4 or 4/0) resulted in antagonistic action. WDL, on the other hand, was found out to be synergistic at any of the applied sequence of drug administration (0/0, 0/4 or 4/0). DISCUSSION AND CONCLUSION: This is the first study reporting cytotoxic activity of WDL in HeLa cells either as single agent or in combination with cisplatin. These results support the idea that sequential combination of cisplatin with WDL and BA may work effectively in cervical cancer cells.

Sequenced Combinations of Cisplatin and Selected Phytochemicals towards Overcoming Drug Resistance in Ovarian Tumour Models.

In the present study, cisplatin, artemisinin, and oleanolic acid were evaluated alone, and in combination, on human ovarian A2780, A2780ZD0473R, and A2780cisR cancer cell lines, with the aim of overcoming cisplatin resistance and side effects. Cytotoxicity was assessed by MTT reduction assay. Combination index (CI) values were used as a measure of combined drug effect. MALDI TOF/TOF MS/MS and 2-DE gel electrophoresis were used to identify protein biomarkers in ovarian cancer and to evaluate combination effects. Synergism from combinations was dependent on concentration and sequence of administration. Generally, bolus was most synergistic. Moreover, 49 proteins differently expressed by 2 ≥ fold were: CYPA, EIF5A1, Op18, p18, LDHB, P4HB, HSP7C, GRP94, ERp57, mortalin, IMMT, CLIC1, NM23, PSA3,1433Z, and HSP90B were down-regulated, whereas hnRNPA1, hnRNPA2/B1, EF2, GOT1, EF1A1, VIME, BIP, ATP5H, APG2, VINC, KPYM, RAN, PSA7, TPI, PGK1, ACTG and VDAC1 were up-regulated, while TCPA, TCPH, TCPB, PRDX6, EF1G, ATPA, ENOA, PRDX1, MCM7, GBLP, PSAT, Hop, EFTU, PGAM1, SERA and CAH2 were not-expressed in A2780cisR cells. The proteins were found to play critical roles in cell cycle regulation, metabolism, and biosynthetic processes and drug resistance and detoxification. Results indicate that appropriately sequenced combinations of cisplatin with artemisinin (ART) and oleanolic acid (OA) may provide a means to reduce side effects and circumvent platinum resistance.

Network-based computational approach to identify genetic links between cardiomyopathy and its risk factors.

Cardiomyopathy (CMP) is a group of myocardial diseases that progressively impair cardiac function. The mechanisms underlying CMP development are poorly understood, but lifestyle factors are clearly implicated as risk factors. This study aimed to identify molecular biomarkers involved in inflammatory CMP development and progression using a systems biology approach. The authors analysed microarray gene expression datasets from CMP and tissues affected by risk factors including smoking, ageing factors, high body fat, clinical depression status, insulin resistance, high dietary red meat intake, chronic alcohol consumption, obesity, high-calorie diet and high-fat diet. The authors identified differentially expressed genes (DEGs) from each dataset and compared those from CMP and risk factor datasets to identify common DEGs. Gene set enrichment analyses identified metabolic and signalling pathways, including MAPK, RAS signalling and cardiomyopathy pathways. Protein-protein interaction (PPI) network analysis identified protein subnetworks and ten hub proteins (CDK2, ATM, CDT1, NCOR2, HIST1H4A, HIST1H4B, HIST1H4C, HIST1H4D, HIST1H4E and HIST1H4L). Five transcription factors (FOXC1, GATA2, FOXL1, YY1, CREB1) and five miRNAs were also identified in CMP. Thus the authors' approach reveals candidate biomarkers that may enhance understanding of mechanisms underlying CMP and their link to risk factors. Such biomarkers may also be useful to develop new therapeutics for CMP.

Machine Learning and Bioinformatics Models to Identify Pathways that Mediate Influences of Welding Fumes on Cancer Progression.

Welding generates and releases fumes that are hazardous to human health. Welding fumes (WFs) are a complex mix of metallic oxides, fluorides and silicates that can cause or exacerbate health problems in exposed individuals. In particular, WF inhalation over an extended period carries an increased risk of cancer, but how WFs may influence cancer behaviour or growth is unclear. To address this issue we employed a quantitative analytical framework to identify the gene expression effects of WFs that may affect the subsequent behaviour of the cancers. We examined datasets of transcript analyses made using microarray studies of WF-exposed tissues and of cancers, including datasets from colorectal cancer (CC), prostate cancer (PC), lung cancer (LC) and gastric cancer (GC). We constructed gene-disease association networks, identified signaling and ontological pathways, clustered protein-protein interaction network using multilayer network topology, and analyzed survival function of the significant genes using Cox proportional hazards (Cox PH) model and product-limit (PL) estimator. We observed that WF exposure causes altered expression of many genes (36, 13, 25 and 17 respectively) whose expression are also altered in CC, PC, LC and GC. Gene-disease association networks, signaling and ontological pathways, protein-protein interaction network, and survival functions of the significant genes suggest ways that WFs may influence the progression of CC, PC, LC and GC. This quantitative analytical framework has identified potentially novel mechanisms by which tissue WF exposure may lead to gene expression changes in tissue gene expression that affect cancer behaviour and, thus, cancer progression, growth or establishment.

Identification of molecular signatures and pathways to identify novel therapeutic targets in Alzheimer's disease: Insights from a systems biomedicine perspective.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. However, there are no peripheral biomarkers available that can detect AD onset. This study aimed to identify the molecular signatures in AD through an integrative analysis of blood gene expression data. We used two microarray datasets (GSE4226 and GSE4229) comparing peripheral blood transcriptomes of AD patients and controls to identify differentially expressed genes (DEGs). Gene set and protein overrepresentation analysis, protein-protein interaction (PPI), DEGs-Transcription Factors (TFs) interactions, DEGs-microRNAs (miRNAs) interactions, protein-drug interactions, and protein subcellular localizations analyses were performed on DEGs common to the datasets. We identified 25 common DEGs between the two datasets. Integration of genome scale transcriptome datasets with biomolecular networks revealed hub genes (NOL6, ATF3, TUBB, UQCRC1, CASP2, SND1, VCAM1, BTF3, VPS37B), common transcription factors (FOXC1, GATA2, NFIC, PPARG, USF2, YY1) and miRNAs (mir-20a-5p, mir-93-5p, mir-16-5p, let-7b-5p, mir-708-5p, mir-24-3p, mir-26b-5p, mir-17-5p, mir-193-3p, mir-186-5p). Evaluation of histone modifications revealed that hub genes possess several histone modification sites associated with AD. Protein-drug interactions revealed 10 compounds that affect the identified AD candidate biomolecules, including anti-neoplastic agents (Vinorelbine, Vincristine, Vinblastine, Epothilone D, Epothilone B, CYT997, and ZEN-012), a dermatological (Podofilox) and an immunosuppressive agent (Colchicine). The subcellular localization of molecular signatures varied, including nuclear, plasma membrane and cytosolic proteins. In the present study, it was identified blood-cell derived molecular signatures that might be useful as candidate peripheral biomarkers in AD. It was also identified potential drugs and epigenetic data associated with these molecules that may be useful in designing therapeutic approaches to ameliorate AD.

Prospects of Wedelolactone as a Chemotherapeutic Agent in Gynecological Cancers; Clue From its In Vitro and In Silico Investigation.

BACKGROUND: Identification and development of new drug candidates to be used singly or in combination therapy is critical in anticancer research. In recent years, accumulating evidence encouraged us to investigate the anti-proliferative effects of a small and emerging phytochemical Wedelolactone (WDL) in estrogen-dependent and independent multiple gynecological tumor models. OBJECTIVE: The aim of this study was to investigate the growth inhibitory effect of WDL on estrogen- dependent and independent gynecological cell lines and to explore its inhibitory potential towards key targets through in silico study. METHODS: Cytotoxicity of WDL was investigated in human breast and ovarian cancer cell lines (MCF-7 and SKOV3) through 3-(4,5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) reduction assay. Epigallocatechingallate (EGCG) was used as reference natural compound while cisplatin was taken as a standard clinical agent. Both WDL and EGCG in combination with cisplatin were also evaluated for their combined growth inhibitory potential in MCF-7 cells. WDL was also evaluated in silico against key factors including braf kinases, CDPK, ERα, aromatase, topoisomerase II and dihydrofolate reductase (DHFR) playing pivotal roles in driving multiple tumors. RESULTS AND DISCUSSION: The IC50 value of WDL was 25.77 ± 4.82 µM and 33.64 ± 1.45 µM in MCF-7 and SKOV-3 respectively. The binding energy order was as follows; WDL: DHFR >Braf kinases > CDPK; aromatase > topoisomerase II> ERα > NFkB > alkaline phosphatase; EGCG dihydrofolatereductase (DHFR) > aromatase >CDPK > topoisomerase II > braf kinases > alkaline phosphatase > CDPK > ERα > NFkB. CONCLUSION: We identified WDL as a cytotoxic agent in breast and ovarian tumor models with the potential to inhibit multiple targets in the oncogenic pathway including estrogen receptor ERα, as depicted through its in silico study. Based on our own research findings and from literature evidence, we conclude that further research should be encouraged to investigate different aspects of wedelolactone as an additional agent to be combined with antiestrogen/endocrine therapy.

Dose and Sequence Dependent Synergism from the Combination of Oxaliplatin with Emetine and Patulin Against Colorectal Cancer.

BACKGROUND: Colorectal cancer is the third most commonly diagnosed cancer in the world, causing many deaths every year. Combined chemotherapy has opened a new horizon in treating colorectal cancer. The objective of the present study is to investigate the activity of oxaliplatin in combination with emetine and patulin against colorectal cancer models. METHODS: IC50 values of oxaliplatin, emetine and patulin were determined against human colorectal cancer cell lines (HT-29 and Caco-2) using MTT reduction assay. Synergistic, antagonistic and additive effects from the selected binary combinations were determined as a factor of sequence of administration and added concentrations. Proteomics was carried out to identify the proteins which were accountable for combined drug action applying to the selected drug combination. RESULTS: Oxaliplatin in combination with patulin produced synergism against human colorectal cancer models depending on dose and sequence of drug administration. Bolus administration of oxaliplatin with patulin proved to be the best in terms of synergistic outcome. Altered expressions of nine proteins (ACTG, PROF1, PPIA, PDIA3, COF1, GSTP1, ALDOA, TBA1C and TBB5) were considered for combined drug actions of oxaliplatin with patulin. CONCLUSION: Bolus administration of oxaliplatin with patulin has the potential to be used in the treatment of colorectal cancer, and would warrant further evaluation using suitable animal model.

Machine learning and bioinformatics models to identify gene expression patterns of ovarian cancer associated with disease progression and mortality.

Ovarian cancer (OC) is a common cause of cancer death among women worldwide, so there is a pressing need to identify factors influencing OC mortality. Much OC patient clinical data is publicly accessible via the Broad Institute Cancer Genome Atlas (TCGA) datasets which include patient age, cancer site, stage and subtype and patient survival, as well as OC gene transcription profiles. These allow studies correlating OC patient survival (and other clinical variables) with gene expression to identify new OC biomarkers to predict patient mortality. We integrated clinical and tissue transcriptome data from patients available from the TCGA portal. We determined OC mRNA expression levels (compared to normal ovarian tissue) of 41 genes already implicated in OC progression, and assessed how their OC tissue expression levels predicts patient survival. We employed Cox Proportional Hazard regression models to analyse clinical factors and transcriptomic information to determine the relative effects on survival that is associated with each factor. Multivariate analysis of combined data (clinical and gene mRNA expression) found age and ovary tumour site significantly correlated with patient survival. The univariate analysis also confirmed significant differences in patient survival time when altered transcription levels of TLR4, BSCL2, CDH1, ERBB2, and SCGB2A1 were evident, while multivariate analysis that considered the 41 genes simultaneously revealed a significant relationship of survival with TLR4, BSCL2, CDH1, ERBB2 and PTPRE genes. However, analyses that considered all 41 genes with clinical variables together identified genes TLR4, BSCL2, CDH1, ERBB2, BRCA2 and SCGB2A1 as independently related to survival in OC. These studies indicate that the latter genes influence OC patient survival, i.e., expression levels of these genes provide mechanistic and predictive information in addition to that of the clinical traits. Our study provides strong evidence that these genes are important prognostic indicators of patient survival that give clues to biological processes that underlie OC progression and mortality.

Discovering Biomarkers and Pathways Shared by Alzheimer's Disease and Ischemic Stroke to Identify Novel Therapeutic Targets.

Background and objectives: Alzheimer's disease (AD) is a progressive neurodegenerative disease that results in severe dementia. Having ischemic strokes (IS) is one of the risk factors of the AD, but the molecular mechanisms that underlie IS and AD are not well understood. We thus aimed to identify common molecular biomarkers and pathways in IS and AD that can help predict the progression of these diseases and provide clues to important pathological mechanisms. Materials and Methods: We have analyzed the microarray gene expression datasets of IS and AD. To obtain robust results, combinatorial statistical methods were used to analyze the datasets and 26 transcripts (22 unique genes) were identified that were abnormally expressed in both IS and AD. Results: Gene Ontology (GO) and KEGG pathway analyses indicated that these 26 common dysregulated genes identified several altered molecular pathways: Alcoholism, MAPK signaling, glycine metabolism, serine metabolism, and threonine metabolism. Further protein-protein interactions (PPI) analysis revealed pathway hub proteins PDE9A, GNAO1, DUSP16, NTRK2, PGAM2, MAG, and TXLNA. Transcriptional and post-transcriptional components were then identified, and significant transcription factors (SPIB, SMAD3, and SOX2) found. Conclusions: Protein-drug interaction analysis revealed PDE9A has interaction with drugs caffeine, γ-glutamyl glycine, and 3-isobutyl-1-methyl-7H-xanthine. Thus, we identified novel putative links between pathological processes in IS and AD at transcripts levels, and identified possible mechanistic and gene expression links between IS and AD.

Genetic effects of welding fumes on the development of respiratory system diseases.

BACKGROUND: The welding process releases potentially hazardous gases and fumes, mainly composed of metallic oxides, fluorides and silicates. Long term welding fume (WF) inhalation is a recognized health issue that carries a risk of developing chronic health problems, particularly respiratory system diseases (RSDs). Aside from general airway irritation, WF exposure may drive direct cellular responses in the respiratory system which increase risk of RSD, but these are not well understood. METHODS: We developed a quantitative framework to identify gene expression effects of WF exposure that may affect RSD development. We analyzed gene expression microarray data from WF-exposed tissues and RSD-affected tissues, including chronic bronchitis (CB), asthma (AS), pulmonary edema (PE), lung cancer (LC) datasets. We built disease-gene (diseasome) association networks and identified dysregulated signaling and ontological pathways, and protein-protein interaction sub-network using neighborhood-based benchmarking and multilayer network topology. RESULTS: We observed many genes with altered expression in WF-exposed tissues were also among differentially expressed genes (DEGs) in RSD tissues; for CB, AS, PE and LC there were 34, 27, 50 and 26 genes respectively. DEG analysis, using disease association networks, pathways, ontological analysis and protein-protein interaction sub-network suggest significant links between WF exposure and the development of CB, AS, PE and LC. CONCLUSIONS: Our network-based analysis and investigation of the genetic links of WFs and RSDs confirm a number of genes and gene products are plausible participants in RSD development. Our results are a significant resource to identify causal influences on the development of RSDs, particularly in the context of WF exposure.

Genetic effects of welding fumes on the progression of neurodegenerative diseases.

BACKGROUND: Welding involves exposure to fumes, gases and radiant energy that can be hazardous to human health. Welding fumes (WFs) comprise a complex mixture of metallic oxides, silicates and fluorides that may result in different health effects. Inhalation of WFs in large quantities over a long periods may pose a risk of developing neurodegenerative diseases (NDGDs), but the nature of this risk is poorly understood. To address this we performed transcriptomic analysis to identify links between WF exposure and NDGDs. METHODS: We developed quantitative frameworks to identify the gene expression relationships of WF exposure and NDGDs. We analyzed gene expression microarray data from fume-exposed tissues and NDGDs including Parkinson's disease (PD), Alzheimer's disease (AD), Lou Gehrig's disease (LGD), Epilepsy disease (ED) and multiple sclerosis disease (MSD) datasets. We constructed disease-gene relationship networks and identified dysregulated pathways, ontological pathways and protein-protein interaction sub-network using multilayer network topology and neighborhood-based benchmarking. RESULTS: We observed that WF associated genes share 18, 16, 13, 19 and 19 differentially expressed genes with PD, AD, LGD, ED and MSD respectively. Gene expression dysregulation along with relationship networks, pathways and ontologic analysis indicate that WFs may be linked to the progression of these NDGDs. CONCLUSIONS: Our developed network-based approach to analysis and investigate the genetic effects of welding fumes on PD, AD, LGD, ED and MSD neurodegenerative diseases could be helpful to understand the causal influences of WF exposure for the progression of the NDGDs.

Polyphenols in Colorectal Cancer: Current State of Knowledge including Clinical Trials and Molecular Mechanism of Action.

Polyphenols have been reported to have wide spectrum of biological activities including major impact on initiation, promotion, and progression of cancer by modulating different signalling pathways. Colorectal cancer is the second most major cause of mortality and morbidity among females and the third among males. The objective of this review is to describe the activity of a variety of polyphenols in colorectal cancer in clinical trials, preclinical studies, and primary research. The molecular mechanisms of major polyphenols related to their beneficial effects on colorectal cancer are also addressed. Synthetic modifications and other future directions towards exploiting of natural polyphenols against colorectal cancer are discussed in the last section.

Changes in the in vitro activity of platinum drugs when administered in two aliquots.

BACKGROUND: The management of ovarian cancer remains a challenge. Because of the lack of early symptoms, it is often diagnosed at a late stage when it is likely to have metastasized beyond ovaries. Currently, platinum based chemotherapy is the primary treatment for the disease. However acquired drug resistance remains an on-going problem. As cisplatin brings about apoptosis by intrinsic and extrinsic pathways, this study aimed to determine changes in activity of platinum drugs when administered in two aliquots as against a bolus and sought to determine association with changes in GSH, speciation of platinum drugs and changes in protein expression. METHODS: The efficacy of administering cisplatin, carboplatin and oxaliplatin in two aliquots with a time gap was investigated in ovarian A2780, A2780(cisR), A2780(ZD0473R) and SKOV-3 cell lines. The cellular accumulation of platinum, level of platinum - DNA binding and cellular glutathione level were determined, and proteomic studies were carried out to identify key proteins associated with platinum resistance in ovarian A2780(cisR) cancer cell line. RESULTS: Much greater cell kill was observed with solutions left standing at room temperature than with freshly prepared solutions, indicating that the increase in activity on ageing was related to speciation of the drug in solution. Proteomic studies identified 72 proteins that were differentially expressed in A2780 and A2780(cisR) cell lines; 22 of them were restored back to normal levels as a result of synergistic treatments, indicating their relevance in enhanced drug action. CONCLUSIONS: The proteins identified are relevant to several different cellular functions including invasion and metastasis, cell cycle regulation and proliferation, metabolic and biosynthesis processes, stress-related proteins and molecular chaperones, mRNA processing, cellular organization/cytoskeleton, cellular communication and signal transduction. This highlights the multifactorial nature of platinum resistance in which many different proteins with diverse functions play key roles. This means multiple strategies can be harnessed to overcome platinum resistance in ovarian cancer. The results of the studies can be significant both from fundamental and clinical view points.

Synthesis of tris(quinoline)monochloroplatinum(II) Chloride and its Activity Alone and in Combination with Capsaicin and Curcumin in Human Ovarian Cancer Cell Lines.

Currently used platinum drugs fail to provide long-term cure for ovarian cancer mainly because of acquired drug resistance. With the idea that the difference may translate into an altered spectrum of activity, monofunctional planaramineplatinum(II) complex tris(quinoline)monochloro-platinum chloride (coded as LH5) was synthesized and investigated for its activity against human ovarian A2780, cisplatin-resistant A2780 (A2780(cisR)) and ZD0473-resistnat A2780 (A2780(ZD0473R)) cancer cell lines alone and in combination with the phytochemicals capsaicin (Caps) and curcumin (Cur) as a function of concentration and sequence of administration. Cell viability was quantified using the MTT reduction assay, while combination was used as a quantitative measure of the combined drug action. LH5 is found to be more active than cisplatin (CS) against both resistant cell lines. Combination of LH5 with capsaicin showed synergism in all three cell lines, with the bolus being most synergistic. Lack of association between the levels of platinum accumulation and platinum-DNA with cytotoxicity can be seen to indicate that binding with DNA may not be the main determinant of activity of LH5. Greater activity of LH5 compared to cisplatin, especially against the resistant cell lines, indicates that the compound may have the potential for development as a novel anticancer drug and that its combination with phytochemicals can serve to further enhance drug efficacy.

Combination of Genistein and Cisplatin with Two Designed Monofunctional Platinum Agents in Human Ovarian Tumour Models.

A great amount of research effort has been directed at platinum compounds that bind with DNA differently from cisplatin with the idea that the difference may translate into an altered spectrum of activity. Recently research has also been directed at applying combinations of platinum agents with tumour-active phytochemicals with the aim of providing a means of overcoming platinum resistance in ovarian cancer. Herein we report the synthesis of monofunctional platinum tris(3-hydroxypyridine)chloroplatinum(II) chloride (coded as LH1) and tris(imidazole)chloroplatinum(II) chloride (coded as LH2), and their activity alone and in combination with genistein and cisplatin against human ovarian A2780, cisplatin-resistant A2780(cisR) and picoplatin-resistant A2780(ZD0473R) cancer cell lines. Although both LH1 and LH2 were found to be less active than cisplatin against the tumour models, they produced synergistic outcomes in combination with genistein. Both the level of cellular accumulation of Pt and of Pt-DNA binding resulting from the combination were greater in the A2780(cisR) cell line than in the parental A2780 cell line, irrespective of the sequence of administration. Absence of association between activity of LH1 and LH2 and the level of Pt-DNA binding indicates that the cell death induced by LH1 and LH2 may not be limited to the effect of their binding with DNA.

Monofunctional Platinum-containing Pyridine-based Ligand Acts Synergistically in Combination with the Phytochemicals Curcumin and Quercetin in Human Ovarian Tumour Models.

With the idea that platinum compounds that bind with DNA differently than cisplatin may be better-able to overcome platinum resistance in ovarian tumor, the monofunctional platinum complex tris(imidazo(1,2-α)pyridine) chloroplatinum(II) chloride (coded as LH6) has been synthesized and investigated for its activity, alone and in combination with the phytochemicals curcumin and quercetin, against human ovarian A2780, A2780(cisR) and A2780(ZD0473R) cancer cell lines. LH6 is found to be more active than cisplatin against the resistant cell lines and its bolus combinations with curcumin and quercetin are found to produce more pronounced cell kill. Whereas platinum accumulation from cisplatin is found to increase almost linearly with time, that from LH6 reaches a maximum at 4 h and is somewhat lowered at 24 h. It is possible that the presence of bulky hydrophobic imidazo (1,2-α-pyridine) ligand in LH6 facilitates its rapid uptake through the cytoplasmic membrane. Lower platinum accumulation at 24 h than at 4 h for LH6 can be seen to imply that efflux processes may be more dominant as the period of incubation is increased. When platinum-DNA binding levels at 24 h are compared, cisplatin is found to be associated with the higher level in the parent A2780 cell line and LH6 in the resistant A2780(cisR) cell line, in line with greater activity of cisplatin in the parent cell line and that of LH6 in the resistant cell line. If the observed in vitro activity of LH6 is confirmed in vivo, it can be seen to have the potential for development as novel platinum based anticancer drug.

Synthesis of a monofunctional platinum compound and its activity alone and in combination with phytochemicals in ovarian tumor models.

Currently used platinum drugs fail to provide long-term cure for ovarian cancer mainly because of acquired drug resistance. In this study, a new monofunctional planaramineplatinum(II) complex, namely tris(8-hydroxyquinoline)monochloroplatinum(II) chloride (coded as LH3), was synthesised and investigated for its activity against human ovarian A2780, cisplatin-resistant A2780 (A2780(cisR)) and ZD0473-resistant A2780 (A2780(ZD0473R)) cancer cell lines, alone and in combination with the phytochemicals curcumin, genistein and resveratrol. Cellular levels of glutathione in A2780 and A2780(cisR) cell lines before and after treatment with LH3 and its combinations with genistein and curcumin were also determined. Interaction of the compounds with salmon sperm DNA, pBR322 plasmid DNA and damage to DNA in A2780 and A2780(cisR) cells due to interaction with LH3-alone and in combination with phytochemicals were also investigated. LH3 was found to be much more active than cisplatin against the resistant tumor models and greatest synergism in activity was observed when combinations of LH3 with genistein and curcumin were administered as a bolus. For combinations of LH3 with the phytochemicals, platinum accumulation and the level of Pt-DNA binding were found to be greater in the resistant A2780(cisR) cell line than in the parental A2780 cell line. Greater activity of LH3 than cisplatin against the resistant ovarian cell lines indicates that it may have the potential for development as a novel anticancer drug and that its combination with phytochemicals can serve to further enhance drug efficacy.