Molecular characterisation of a panel of human ovarian carcinoma xenografts

Evolution of network biomarkers from early to late stage bladder cancer samples

We use a systems biology approach to construct protein-protein interaction networks (PPINs) for early and late stage bladder cancer. By comparing the networks of these two stages, we find that both networks showed very significantly different mechanisms. To obtain the differential network structures between cancer and noncancer PPINs, we constructed cancer PPIN and noncancer PPIN network structures for the two bladder cancer stages using microarray data from cancer cells and their adjacent noncancer cells, respectively. With their carcinogenesis relevance values (CRVs), we identified 152 and 50 significant proteins and their PPI networks (network markers) for early and late stage bladder cancer by statistical assessment. To investigate the evolution of network biomarkers in the carcinogenesis process, primary pathway analysis showed that the significant pathways of early stage bladder cancer are related to ordinary cancer mechanisms, while the ribosome pathway and spliceosome pathway are most important for late stage bladder cancer. Their only intersection is the ubiquitin mediated proteolysis pathway in the whole stage of bladder cancer. The evolution of network biomarkers from early to late stage can reveal the carcinogenesis of bladder cancer. The findings in this study are new clues specific to this study and give us a direction for targeted cancer therapy, and it should be validated in vivo or in vitro in the future.

Core and specific network markers of carcinogenesis from multiple cancer samples

Cancer is the leading cause of death worldwide and is generally caused by mutations in multiple proteins or the dysregulation of pathways. Understanding the causes and the underlying carcinogenic mechanisms can help fight this disease. In this study, a systems biology approach was used to construct the protein-protein interaction (PPI) networks of four cancers and the non-cancers by their corresponding microarray data, PPI modeling and database-mining. By comparing PPI networks between cancer and non-cancer samples to find significant proteins with large PPI changes during carcinogenesis process, core and specific network markers were identified by the intersection and difference of significant proteins, respectively, with carcinogenesis relevance values (CRVs) for each cancer. A total of 28 significant proteins were identified as core network markers in the carcinogenesis of four types of cancer, two of which are novel cancer-related proteins (e.g., UBC and PSMA3). Moreover, seven crucial common pathways were found among these cancers based on their core network markers, and some specific pathways were particularly prominent based on the specific network markers of different cancers (e.g., the RIG-I-like receptor pathway in bladder cancer, the proteasome pathway and TCR pathway in liver cancer, and the HR pathway in lung cancer). Additional validation of these network markers using the literature and new tested datasets could strengthen our findings and confirm the proposed method. From these core and specific network markers, we could not only gain an insight into crucial common and specific pathways in the carcinogenesis, but also obtain a high promising PPI target for cancer therapy.

Gamma irradiation and targeted radionuclides enhance the expression of the noradrenaline transporter transgene controlled by the radio-inducible p21(WAF1/CIP1) promoter

The use of radiation-inducible promoters to drive transgene expression offers the possibility of temporal and spatial regulation of gene activation. This study assessed the potential of one such promoter element, p21(WAF1/CIP1) (WAF1), to drive expression of the noradrenaline transporter (NAT) gene, which conveys sensitivity to radioiodinated meta-iodobenzylguanidine (MIBG). An expression vector containing NAT under the control of the radiation-inducible WAF1 promoter (pWAF/NAT) was produced. The non-NAT expressing cell lines UVW (glioma) and HCT116 (colorectal cancer) were transfected with this construct to assess radiation-controlled WAF1 activation of the NAT gene. Transfection of UVW and HCT cells with pWAF/NAT conferred upon them the ability to accumulate [(131)I]MIBG, which led to increased sensitivity to the radiopharmaceutical. Pretreatment of transfected cells with γ radiation or the radiopharmaceuticals [(123)I]MIBG or [(131)I]MIBG induced dose- and time-dependent increases in subsequent [(131)I]MIBG uptake and led to enhanced efficacy of [(131)I]MIBG-mediated cell kill. Gene therapy using WAF1-driven expression of NAT has the potential to expand the use of this therapeutic modality to tumors that lack a radio-targetable feature.

Cisplatin plus paclitaxel and maintenance of bevacizumab on tumour progression, dissemination, and survival of ovarian carcinoma xenograft models

Background:

Bevacizumab is being incorporated as first-line therapy with standard-of-care chemotherapy on epithelial ovarian carcinoma (EOC). We investigated bevacizumab combined with chemotherapy on tumour progression and mouse survival in EOC xenograft models.

Methods:

Bevacizumab was administered concomitantly with cisplatin plus paclitaxel (DDP+PTX), continued after induction (maintenance) or started after chemotherapy. The effect on tumour progression was monitored by bioluminescence imaging (BLI) (1A9-luc xenograft). Tumour dissemination into the peritoneal organs and ascites formation (HOC22 xenograft) was evaluated by histological analysis at the end of treatment (interim) and at euthanasia (survival). The effects on overall survival (OS) were investigated in both EOC models.

Results:

Bevacizumab with PTX+DDP delayed tumour progression in mice bearing EOC xenografts. OS was significantly extended, with complete responses, by bevacizumab continued after stopping chemotherapy in the HOC22 xenograft. Bevacizumab alone inhibited ascites formation, with only limited effect on tumour burden, but combined with PTX+DDP reduced ascites and metastases. Bevacizumab started after induction with PTX+DDP and maintained was equally effective on tumour progression and survival on 1A9-luc xenograft.

Conclusion:

Bevacizumab combined with chemotherapy not only affected tumour progression, but when administered as maintenance regimen significantly prolonged survival, reducing ascites, and tumour dissemination. We believe our findings are consistent with the clinical results and shed light on the potential effects of this kind of treatment on tumour progression.

An indicator of cancer: downregulation of monoamine oxidase-A in multiple organs and species

Background

Identifying consistent changes in cellular function that occur in multiple types of cancer could revolutionize the way cancer is treated. Previous work has produced promising results such as the identification of p53. Recently drugs that affect serotonin reuptake were shown to reduce the risk of colon cancer in man. Here, we analyze an ensemble of cancer datasets focusing on genes involved in the serotonergic pathway. Genechip datasets consisting of cancerous tissue from human, mouse, rat, or zebrafish were extracted from the GEO database. We first compared gene expression between cancerous tissues and normal tissues for each type of cancer and then identified changes that were common to a variety of cancer types.

Results

Our analysis found that significant downregulation of MAO-A, the enzyme that metabolizes serotonin, occurred in multiple tissues from humans, rodents, and fish. MAO-A expression was decreased in 95.4% of human cancer patients and 94.2% of animal cancer cases compared to the non-cancerous controls.

Conclusion

These are the first findings that identify a single reliable change in so many different cancers. Future studies should investigate links between MAO-A suppression and the development of cancer to determine the extent that MAO-A suppression contributes to increased cancer risk.

p21(WAF1)-mediated transcriptional targeting of inducible nitric oxide synthase gene therapy sensitizes tumours to fractionated radiotherapy

Cancer gene therapy that utilizes toxic transgene products requires strict transcriptional targeting to prevent adverse normal tissue effects. We report on the use of a promoter derived from the cyclin dependent kinase inhibitor, p21((WAF1)), to control transgene expression. We demonstrate that this promoter is relatively silent in normal cells (L132, FSK, HMEC-1) compared to the almost constitutive expression obtained in tumour cells (DU145, LNCaP, HT29 and MCF-7) of varying p53 status, a characteristic that will be important in gene therapy protocols. In addition, we found that the p21((WAF1)) promoter could be further induced by both external beam radiation (up to eight-fold in DU145 cells), intracellular-concentrated radionuclides ([(211)At]MABG) (up to 3.5-fold in SK-N-BE(2c) cells) and hypoxia (up to four-fold in DU145 cells). We have previously achieved significant radiosensitization of tumour cells both in vitro and in vivo by using inducible nitric oxide synthase (iNOS) gene therapy to generate the potent radiosensitizer, nitric oxide (NO(.-)). Here, we report that a clinically relevant schedule of p21((WAF1))-driven iNOS gene therapy significantly sensitized both p53 wild-type RIF-1 tumours and p53 mutant HT29 tumours to fractionated radiotherapy. Our data highlight the utility of this p21((WAF1))/iNOS-targeted approach.

Gene expression correlating with response to paclitaxel in ovarian carcinoma xenografts

We have investigated gene expression profiles of human ovarian carcinomas in vivo during Taxol® (paclitaxel) treatment and observed a difference in expression. Nude mice bearing 1A9 or 1A9PTX22 xenografts were given 60 mg/kg of paclitaxel. Therapeutic efficacy was achieved for 1A9, while 1A9PTX22 did not respond. Tumor tissues harvested 4 and 24 h after treatment were evaluated by cDNA microarray against untreated tumors. Paclitaxel caused the modulation of more genes in 1A9 than in 1A9PTX22 tumors, in accordance to their therapeutic response. Most gene expression alterations were detected 24 h after paclitaxel administration and affected genes involved in various biological functions including cell cycle regulation and cell proliferation (CDC2, CDKN1A, PLAB, and TOP2A), apoptosis (BNIP3 and PIG8), signal transduction and transcriptional regulation (ARF1, ATF2, FOS, GNA11, HDAC3, MADH2, SLUG, and SPRY4), fatty acid biosynthesis and sterol metabolism (FDPS, IDI1, LIPA, and SC5D), and IFN-mediated signaling (G1P3, IFI16, IFI27, IFITM1, and ISG15). The modulation of two representative genes, CDKN1A and TOP2A, was validated by Northern analyses on a panel of seven ovarian carcinoma xenograft models undergoing treatment with paclitaxel. We found that the changes in expression level of these genes was strictly associated with the responsiveness to paclitaxel. Our study shows the feasibility of obtaining gene expression profiles of xenografted tumor models as a result of drug exposure. This in turn might provide insights related to the drugs' action in vivo that will anticipate the response to treatment manifested by tumors and could be the basis for novel approaches to molecular pharmacodynamics.

Transcriptional Targeting in Cancer Gene Therapy

Cancer gene therapy has been one of the most exciting areas of therapeutic research in the past decade. In this review, we discuss strategies to restrict transcription of transgenes to tumour cells. A range of promoters which are tissue-specific, tumour-specific, or inducible by exogenous agents are presented. Transcriptional targeting should prevent normal tissue toxicities associated with other cancer treatments, such as radiation and chemotherapy. In addition, the specificity of these strategies should provide improved targeting of metastatic tumours following systemic gene delivery. Rapid progress in the ability to specifically control transgenes will allow systemic gene delivery for cancer therapy to become a real possibility in the near future.

Genetic alterations in ovarian cancer cells that might account for sensitivity to chemotherapy in patients

The cellular response to anticancer agent treatments is determined by many factors that could be altered in tumor cells. The induction of apoptosis of cancer cells is thought to be important for the overall response of these cells. Despite the introduction of new and potent anticancer agents, the survival rate for patients with ovarian cancer remains poor. In general ovarian cancer cells present a poor propensity to undergo apoptosis, which could be one of the reasons for this relatively poor response observed in the clinic. Induction of apoptosis is the result of activation and repression of pro- and antiapoptotic genes, which are regulated by complex mechanisms. Many cancer cells activate a "survival" program to escape disruption and allow propagation. In this review we have analyzed the role of genetic alterations observed in ovarian cancer cells in determining cellular response to drug treatment.