Searching for new strategies for effective elimination of human prostate cancer cells, we investigated the cooperative cytotoxic action of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and two platinum-based complexes, cisplatin or LA-12, and related molecular mechanisms. We demonstrated a notable ability of cisplatin or LA-12 to enhance the sensitivity of several human prostate cancer cell lines to TRAIL-induced cell death via an engagement of mitochondrial apoptotic pathway. This was accompanied by augmented Bid cleavage, Bak activation, loss of mitochondrial membrane potential, activation of caspase-8, -10, -9, and -3, and XIAP cleavage. RNAi-mediated silencing of Bid or Bak in Bax-deficient DU 145 cells suppressed the drug combination-induced cytotoxicity, further underscoring the involvement of mitochondrial signaling. The caspase-10 was dispensable for enhancement of cisplatin/LA-12 and TRAIL combination-induced cell death and stimulation of Bid cleavage. Importantly, we newly demonstrated LA-12-mediated enhancement of TRAIL-induced cell death in cancer cells derived from human patient prostate tumor specimens. Our results provide convincing evidence that employing TRAIL combined with cisplatin/LA-12 could contribute to more effective killing of prostate cancer cells compared to the individual action of the drugs, and offer new mechanistic insights into their cooperative anticancer action.

• MeSH
• Amantadine analogs & derivatives   pharmacology   MeSH
• Apoptosis drug effects   MeSH
• Cisplatin pharmacology   MeSH
• Caspase 10 metabolism   MeSH
• Humans MeSH
• Mitochondria drug effects   metabolism   MeSH
• Prostatic Neoplasms metabolism   pathology   MeSH
• Organoplatinum Compounds pharmacology   MeSH
• BH3 Interacting Domain Death Agonist Protein metabolism   MeSH
• TNF-Related Apoptosis-Inducing Ligand metabolism   MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amantadine MeSH
• BID protein, human MeSH Browser
• bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) MeSH Browser
• Cisplatin MeSH
• Caspase 10 MeSH
• Organoplatinum Compounds MeSH
• BH3 Interacting Domain Death Agonist Protein MeSH
• TNF-Related Apoptosis-Inducing Ligand MeSH

Although Chk1 kinase inhibitors are currently under clinical investigation as effective cancer cell sensitizers to the cytotoxic effects of numerous chemotherapeutics, there is still a considerable uncertainty regarding their role in modulation of anticancer potential of platinum-based drugs. Here we newly demonstrate the ability of one of the most specific Chk1 inhibitors, SCH900776 (MK-8776), to enhance human colon cancer cell sensitivity to the cytotoxic effects of platinum(II) cisplatin and platinum(IV)- LA-12 complexes. The combined treatment with SCH900776 and cisplatin or LA-12 results in apparent increase in G1/S phase-related apoptosis, stimulation of mitotic slippage, and senescence of HCT116 cells. We further show that the cancer cell response to the drug combinations is significantly affected by the p21, p53, and PTEN status. In contrast to their wt counterparts, the p53- or p21-deficient cells treated with SCH900776 and cisplatin or LA-12 enter mitosis and become polyploid, and the senescence phenotype is strongly suppressed. While the cell death induced by SCH900776 and cisplatin or LA-12 is significantly delayed in the absence of p53, the anticancer action of the drug combinations is significantly accelerated in p21-deficient cells, which is associated with stimulation of apoptosis beyond G2/M cell cycle phase. We also show that cooperative killing action of the drug combinations in HCT116 cells is facilitated in the absence of PTEN. Our results indicate that SCH900776 may act as an important modulator of cytotoxic response triggered by platinum-based drugs in colon cancer cells.

• MeSH
• Apoptosis drug effects   MeSH
• Cell Cycle drug effects   genetics   MeSH
• Checkpoint Kinase 1 antagonists & inhibitors   genetics   metabolism   MeSH
• Cisplatin pharmacology   MeSH
• Gene Knockout Techniques MeSH
• Cyclin-Dependent Kinase Inhibitor p21 genetics   metabolism   MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 genetics   metabolism   MeSH
• Colonic Neoplasms drug therapy   genetics   metabolism   pathology   MeSH
• DNA Damage drug effects   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Pyrazoles pharmacology   MeSH
• Pyrimidines pharmacology   MeSH
• Platinum Compounds pharmacology   MeSH
• Cellular Senescence drug effects   MeSH
• Cell Survival drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Checkpoint Kinase 1 MeSH
• CHEK1 protein, human MeSH Browser
• Cisplatin MeSH
• Cyclin-Dependent Kinase Inhibitor p21 MeSH
• MK-8776 MeSH Browser
• Tumor Suppressor Protein p53 MeSH
• Antineoplastic Agents MeSH
• Pyrazoles MeSH
• Pyrimidines MeSH
• Platinum Compounds MeSH

We demonstrated for the first time an outstanding ability of rosiglitazone to mediate a profound enhancement of LA-12-induced apoptosis associated with activation of mitochondrial pathway in human colon cancer cells. This effect was preferentially observed in the G1 cell cycle phase, independent on p53 and PPARγ proteins, and accompanied with significant changes of selected Bcl-2 family protein levels. Further stimulation of cooperative synergic cytotoxic action of rosiglitazone and LA-12 was demonstrated in the cells deficient for PTEN, where mitochondrial apoptotic pathway was more stimulated and G1-phase-associated dying was reinforced. Our results suggest that combined treatment with rosiglitazone and LA-12 might be promising anticancer strategy in colon-derived tumours regardless of their p53 status, and also favourable in those defective in PTEN function.

• MeSH
• Amantadine analogs & derivatives   pharmacology   MeSH
• Apoptosis drug effects   MeSH
• Cell Cycle drug effects   MeSH
• Energy Metabolism drug effects   MeSH
• PTEN Phosphohydrolase genetics   MeSH
• HCT116 Cells MeSH
• G1 Phase Cell Cycle Checkpoints drug effects   MeSH
• Humans MeSH
• RNA, Small Interfering MeSH
• Membrane Potential, Mitochondrial drug effects   MeSH
• Mitochondria metabolism   MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Colonic Neoplasms drug therapy   MeSH
• Organoplatinum Compounds pharmacology   MeSH
• PPAR gamma genetics   MeSH
• Cell Proliferation drug effects   MeSH
• Antineoplastic Agents pharmacology   MeSH
• RNA Interference MeSH
• Rosiglitazone MeSH
• Drug Synergism MeSH
• Thiazolidinediones pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Amantadine MeSH
• bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) MeSH Browser
• PTEN Phosphohydrolase MeSH
• RNA, Small Interfering MeSH
• Tumor Suppressor Protein p53 MeSH
• Organoplatinum Compounds MeSH
• PPAR gamma MeSH
• Antineoplastic Agents MeSH
• Pten protein, mouse MeSH Browser
• Rosiglitazone MeSH
• Thiazolidinediones MeSH

OBJECTIVES: Therapeutic potential of conventionally used platinum-based drugs in treatment of colorectal tumours has been limited due to high incidence of tumour resistance to them and to their severe side effects. This evokes a search for more suitable anti-cancer drugs. We have compared ability of oxaliplatin and a novel platinum(IV) complex, LA-12, to modulate the cell cycle and induce apoptosis in human colon adenocarcinoma HCT116 wt and p53/p21 null cells, and have investigated molecular mechanisms involved. MATERIALS AND METHODS: Cell cycle-related changes were analysed by flow cytometry (bromodeoxyuridine/propidium iodide staining, histone H3 phosphorylation). Apoptosis was detected using flow cytometry (assays monitoring caspase activity) and fluorescence microscopy (nuclear morphology). Changes in levels of genes/proteins involved in cell cycle and apoptosis regulation were examined by RT-PCR and western blotting. RESULTS: Our results highlight the outstanding ability of LA-12 to induce effective elimination of colon cancer cells independently of p53/p21, and in significantly lower doses compared to oxaliplatin. While oxaliplatin induced p53- and p21-dependent G2 -phase arrest associated with downregulation of cyclin B1 and Cdk1, LA-12 allowed cells to enter M-phase of the cell cycle regardless of p53/p21 status. CONCLUSIONS: Higher malignant cell toxicity and ability to bypass cell cycle arrest important for the cell damage repair suggest LA-12 to be a more effective candidate for elimination of colon tumours from a variety of genetic backgrounds, compared with oxaliplatin.

• MeSH
• Adenocarcinoma drug therapy   genetics   MeSH
• Amantadine analogs & derivatives   pharmacology   MeSH
• Apoptosis drug effects   genetics   MeSH
• Cell Division drug effects   genetics   MeSH
• Cyclin B1 genetics   MeSH
• HCT116 Cells MeSH
• Cyclin-Dependent Kinase Inhibitor p21 genetics   MeSH
• Humans MeSH
• Mitosis drug effects   genetics   MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Colonic Neoplasms drug therapy   genetics   MeSH
• Organoplatinum Compounds pharmacology   MeSH
• Oxaliplatin MeSH
• Cell Proliferation drug effects   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Amantadine MeSH
• bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) MeSH Browser
• CDKN1A protein, human MeSH Browser
• Cyclin B1 MeSH
• Cyclin-Dependent Kinase Inhibitor p21 MeSH
• Tumor Suppressor Protein p53 MeSH
• Organoplatinum Compounds MeSH
• Oxaliplatin MeSH
• Antineoplastic Agents MeSH

BACKGROUND: The initial pharmacokinetic study of a new anticancer agent (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum (IV) (LA-12) was complemented by proteomic screening of rat plasma. The objective of the study was to identify new LA-12 target proteins that serve as markers of LA-12 treatment, response and therapy monitoring. METHODS: Proteomic profiles were measured by surface-enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF MS) in 72 samples of rat plasma randomized according to LA-12 dose and time from administration. Correlation of 92 peak clusters with platinum concentration was evaluated using Spearman correlation analysis. RESULTS: We identified Retinol-binding protein 4 (RBP4) whose level correlated with LA-12 level in treated rats. Similar results were observed in randomly selected patients involved in Phase I clinical trials. CONCLUSIONS: RBP4 induction is in agreement with known RBP4 regulation by amantadine and cisplatin. Since retinol metabolism is disrupted in many cancers and inversely associates with malignancy, these data identify a potential novel mechanism for the action of LA-12 and other similar anti-cancer drugs.

• Publication type
• Journal Article MeSH

BACKGROUND: Cisplatin and its derivatives are commonly used anti-cancer drugs. However, cisplatin has clinical limitations including serious side effects and frequent emergence of intrinsic or acquired resistance. Thus, the novel platinum(IV) complex LA-12 represents a promising treatment modality, which shows increased intracellular penetration resulting in improved cytotoxicity in various cancer cell lines, including cisplatin resistant cells. RESULTS: LA-12 disrupts cellular proliferation regardless of the p53 status in the cells, however the potency of the drug is greatly enhanced by the presence of a functional p53, indicating several mechanisms of action. Similarly to cisplatin, an interaction of LA-12 with molecular chaperone Hsp90 was proposed. Binding of LA-12 to Hsp90 was demonstrated by Hsp90 immunoprecipitation followed by platinum measurement using atomic absorption spectrometry (AAS). An inhibitory effect of LA-12 on Hsp90 chaperoning function was shown by decrease of Hsp90-assisted wild-type p53 binding to p21WAF1 promoter sequence in vitro and by accelerated ubiqutination and degradation of primarily unfolded mutant p53 proteins in cells exposed to LA-12. CONCLUSIONS: To generalize our findings, LA-12 induced degradation of other Hsp90 client proteins such as Cyclin D1 and estrogen receptor was shown and proved as more efficient in comparison with cisplatin. This newly characterised molecular mechanism of action opens opportunities to design new cancer treatment strategy profitable from unique LA-12 properties, which combine DNA damaging and Hsp90 inhibitory effects.

• MeSH
• Amantadine analogs & derivatives   pharmacology   MeSH
• Cisplatin pharmacology   MeSH
• Immunoprecipitation MeSH
• Cyclin-Dependent Kinase Inhibitor p21 drug effects   metabolism   MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 drug effects   metabolism   MeSH
• Organoplatinum Compounds pharmacology   MeSH
• HSP90 Heat-Shock Proteins drug effects   metabolism   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Spectrophotometry, Atomic MeSH
• Blotting, Western MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Amantadine MeSH
• bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) MeSH Browser
• CDKN1A protein, human MeSH Browser
• Cisplatin MeSH
• Cyclin-Dependent Kinase Inhibitor p21 MeSH
• Tumor Suppressor Protein p53 MeSH
• Organoplatinum Compounds MeSH
• HSP90 Heat-Shock Proteins MeSH
• Antineoplastic Agents MeSH

Platinum (IV) derivative with adamantylamine-LA-12-represents a new generation of highly efficient anti-cancer drug derived from cisplatin and is currently in the final stage of phase I clinical trials. Understanding the specific mechanisms of its effects on cell cycle is necessary for defining the mode of action of LA-12. In this study, we characterized the ability of LA-12 to induce cell cycle perturbations in ovarian cancer cell line A2780 as compared to equitoxic cisplatin treatment. LA-12 induced a permanent accumulation of A2780 cells in S phase while cisplatin caused G2/M arrest at 24-h time point, where we also detected an increased expression of Gadd45alpha protein. Although both derivatives induced a rapid increase of p53 expression, this was not associated with a down-regulation of Mdm2 protein. Increased expression of p21(Cip1/WAF1) protein and its association with cyclins A and B1 suggested that this cyclin-dependent kinase inhibitor might contribute significantly to the observed perturbations of cell cycle. The results of this study provide insight into the mechanism of action of platinum-based derivative with adamantylamine on cell cycle in ovarian cancer cells. The differences between effects of LA-12 and cisplatin suggest that more attention should be paid to elucidation of modes of action of novel platinum(IV) complexes at cellular level.

• MeSH
• Amantadine analogs & derivatives   pharmacology   MeSH
• Cell Cycle drug effects   MeSH
• Cisplatin pharmacology   MeSH
• Carcinoma drug therapy   metabolism   MeSH
• Humans MeSH
• Cell Line, Tumor MeSH
• Tumor Suppressor Protein p53 metabolism   MeSH
• Ovarian Neoplasms drug therapy   metabolism   MeSH
• Organoplatinum Compounds pharmacology   MeSH
• Cell Proliferation drug effects   MeSH
• bcl-2-Associated X Protein metabolism   MeSH
• Cell Cycle Proteins metabolism   MeSH
• Antineoplastic Agents pharmacology   MeSH
• Proto-Oncogene Proteins c-mdm2 metabolism   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Amantadine MeSH
• bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) MeSH Browser
• Cisplatin MeSH
• MDM2 protein, human MeSH Browser
• Tumor Suppressor Protein p53 MeSH
• Organoplatinum Compounds MeSH
• bcl-2-Associated X Protein MeSH
• Cell Cycle Proteins MeSH
• Antineoplastic Agents MeSH
• Proto-Oncogene Proteins c-mdm2 MeSH