Anthracene was attached to light activated, ruthenium-based DNA disruptors to probe their distribution in cancer cells. The objective of this research is to understand the photophysical properties (Chapter 2), photoreactivity toward DNA and proteins (Chapter 3), and localization within cancer cells (Chapter 4) of ruthenium complexes that demonstrate promise as photodynamic therapy (PDT) agents. [(AnthbpyMe)(bpy)Ru(dpp)]2+ (1) and [(AnthbpyMe)2Ru(dpp)]2+ (2) absorb visible light with metal-to-ligand charge transfer (MLCT) transitions at 459 nm (16,000 M-1 cm-1 ) and 461 nm (21,000 M-1 cm-1 ), respectively. These species exhibit 3 MLCT emissions at λem = 661 nm and λem = 663 nm for 1 and 2, respectively, while the anthracene show emissions at 450 – 560 nm. The anthracene unit(s) quench the 3 MLCT to give quantum yields (lifetime) of Φem = 0.0059 [398(1) ns] and Φem = 0.0011 [414(1) ns] for 1 and 2, respectively. Voltammetry shows an irreversible anthracene oxidation at 1.23 – 1.28 V, RuIII/II oxidation at 1.53 – 1.55 V, and quasi-reversible reduction couples attributed to dpp0/-1 at 0.98 V. DNA gel shift assays demonstrate that complexes 1 and 2 modify DNA in the presence and absence of 3 O2 upon light activation to convert supercoiled DNA to a mixture of open circular (OC) DNA and a species that exhibit sa distinctly different migration rate than either OC and linear DNA. Binding constants, Kb, for complexes 1 and 2, toward DNA are 3.50 × 105 (3.50 × 104 ) and 4.50 × 103 (4.50 × 102 ) respectively. SDS-PAGE assays show that the complexes 1 and 2 modify bovine serum albumin (BSA) through an 3 O2-dependent mechanism upon light iii activation. The localization and PDT potency of the anthracene-Ru-dpp complexes are tested against F98 cells, which are rat glioma cells that simulate the infiltrative patterns of growth in cancer. Confocal microscopy demonstrates that complexes 1 and 2 internalize and localize primarily along the cell membrane and associate with dot-like vesicles within the cytoplasm. Complexes 1 and 2 show IC50 values of 107 µM and 85 µM, respectively, after 15 min of drug exposure and 1 h of PDT-treatment (λPDT = 455 nm). / Ph. D.

No / Methionine dependence is unique to cancer cells and defined as the inability to grow in a methionine-deprived environment even if supplemented with the metabolic precursor homocysteine. Cobalamin-dependent methionine synthase (MS) catalyses the formation of methionine and tetrahydrofolate from homocysteine and methyltetrahydrofolate, thus linking the methionine and folate pathways. The apparent altered methionine metabolism in methionine-dependent cancer cells suggests a role for MS, although results to date are conflicting. We have analysed key metabolites of the MS-associated transmethylation, transsulphuration and folate pathways of the methionine-dependent MAC15A tumour model as a function of tumour progression over a 10-day period. MS activity increased 2-fold from day I to day 10. Cysteine, homocysteine, S-adenosylmethionine and S-adenosylhomocysteine levels in tumour cytosolic fractions decreased as a function of tumour progression. Plasma cysteine levels also decreased, whilst the distribution of folates in erythrocytes was altered, with a maximum increase in methyltetrahydrofolate observed by day 5. The increasing MS activity and decreasing cysteine levels suggest an increasing methionine requirement by the tumour, whilst the induction of enzyme activity indicates that MS is not defective in the methionine-dependent MAC15A tumour. The decrease in tumour S-adenosylmethionine and S-adenosylhomocysteine levels suggests that methionine is required for some function other than cellular methylation, e.g., incorporation into protein. Overall, the results support a theory of methionine conservation in response to tumour growth, where the methionine-dependent MAC15A tumour has a higher than normal methionine requirement.

Bakgrund   Malignt tumörsår utvecklas hos 5–10 procent av personer med avancerad cancer och är en direkt konsekvens av sjukdomen, vilket leder till ytterligare komplikationer och obehag. Den fysiska smärtan och odör vid maligna tumörsår kräver vanligtvis en kombination av behandlingar, inklusive lokal och avancerad sårvård. Dessa två symtom genererade konsekvenser ur många perspektiv, vilket undersöks ur de fysiska, psykiska, sociala och existentiella dimensionerna utifrån teorin total pain. Syfte Syftet med denna uppsats var att belysa personers erfarenhet av att leva med maligna tumörsår. Metod Uppsatsen var en icke-systematisk litteraturöversikt som baserades på artiklar med både kvalitativ och kvantitativ ansats. Tio vetenskapliga artiklar valdes ut och hämtades från databaserna PubMed och CINAHL. Varje artikel kvalitetsgranskades noggrant enligt bedömningskriterierna för vetenskaplig klassificering och kvalitet via Sophiahemmet Högskola. En integrerad analysmetod tillämpades för sammanställning och bearbetning av resultaten från de olika studierna.  Resultat Maligna tumörsår orsakade betydande fysiska och psykologiska utmaningar för de drabbade, deras närstående och vårdpersonal. Smärtan var intensiv och svårbehandlad. Odören beskrevs som påträngande och svår kontrollerad. De psykologiska utmaningarna inkluderade skam och ångest, medan social isolering förstärktes av sårens odör och synlighet. Existentiella utmaningarna uppstod av att hantera en obotlig sjukdom och önskan om en fridfull död. Slutsats Uppsatsen belyste att personer med maligna tumörsår hade erfarenheter av lidande ur flera dimensioner. Enligt Saunders' teori krävdes en omfattande förståelse av smärtans alla aspekter för att förbättra välbefinnandet hos dessa personer. Effektiv hantering och identifiering av symtom relaterade till maligna tumörsår krävde utökad kunskap inom vården. Dessutom var det viktigt att öka allmänhetens medvetenhet för att minska stigma och skam kring tillståndet maligna tumörsår. / Background Malignant fungating wounds, occurring in 5-10 percent of individuals with advanced cancer, directly result from the disease and lead to significant complications and discomfort. Managing physical pain and odor often involves a combination of treatments, including local medications and advanced wound care. These two symptoms generated consequences from different perspectives, which is examined from the physical, psychological, social, and existential dimensions based on the theory of total pain. Aim The purpose of this study was to highlight the experiences of people living with malignant fungating wounds. Method The study was a non-systematic literature review based on articles with both qualitative and quantitative approaches. Ten scientific articles were selected and retrieved from the PubMed and CINAHL databases. Each article was meticulously quality assessed according to the criteria for scientific classification and quality via Sophiahemmet University College. An integrated analysis method was applied to compile and process the results from the numerous studies. Results Malignant fungating wounds caused significant physical and psychological challenges for those affected, their relatives, and healthcare providers. The pain was intense and difficult to treat. The odor was described as intrusive and hard to control. Psychological challenges included shame and anxiety, while social isolation was exacerbated by the odor and visibility of the wounds. Existential challenges arose from dealing with an incurable disease and the desire for a peaceful death. Conclusions The study highlighted those persons with malignant fungating wounds experienced suffering from multiple dimensions. According to Saunders' theory, a comprehensive understanding of all aspects of pain was required to improve the well-being of these individuals. Effective management and identification of symptoms related to malignant wounds required expanded knowledge within healthcare. Additionally, it was important to increase public awareness to reduce the stigma and shame associated with the condition of malignant fungating wounds.

This thesis deals with encounters between persons living with dementia and care managers. Dementia often results in progressive care needs that must be met by different social care services. The person’s care needs are assessed in an assessment meeting where the person and their relatives meet with a care manager to negotiate needs and social care services. The assessment is conducted through one or several conversations where the person with dementia meets the care manager; relatives are often present in the meetings. Dementia is a syndrome that involves a cognitive decline and a decreased ability to communicate and interact with others. It may therefore be difficult for a person with dementia to take part in discussions about their care needs and social care services. 15 audio recorded meetings have been studied to explore and understand how persons with dementia use their remaining communicative, cognitive and linguistic resources to invoke, negotiate, and use their rights as citizens in the institutional context where their care needs are assessed. The analysis concerns the organization of talk as a joint activity; the production of social actors in talk-in-interaction; the relation to institutional features of discourse. This dissertation concludes that the practice of citizenship is situation based and varies depending on the participants present. Care managers can facilitate for persons with dementia to overcome communication problems by using different discursive strategies and to make it possible for them to participate or at least be included in the negotiation. Persons with dementia are positioned as less competent than other persons participating in the assessment meeting. This might have an impact on the participation of people with dementia in negotiations regarding their future care. Furthermore, stories told in assessment meetings often position the person as dependent on others, which could undermine the identity and sense of self of the person with dementia. / Den här avhandlingen berör möten mellan personer med demenssjukdom och biståndshandläggare. Demenssjukdomar medför ofta komplexa omsorgsbehov, vilka kan mötas med hjälp av olika stödinsatser. Personens omsorgsbehov bedöms i ett biståndshandläggningssamtal där personen och dennes anhöriga träffar en biståndshandläggare för att förhandla dennes behov och eventuella insatser. Konversation är centralt i dessa möten. Demenssjukdomar medför kognitiva nedsättningar och nedsatt förmåga att kommunicera och interagera med andra. Det kan därför vara svårt för personer med demenssjukdom att deltaga i diskussioner om behov och insatser. 15 ljudinspelade samtal har studerats för att förstå hur personer med demens använder sina kvarvarande kommunikativa, kognitiva och språkliga resurser för att åberopa, förhandla och använda sina rättigheter som medborgare i den institutionella kontext där deras omsorgsbehov bedöms. I samtalet medverkar personen med demens, handläggaren samt ofta någon familjemedlem. Analysen fokuserar på organiseringen av samtal som en gemensam aktivitet; hur sociala aktörer skapas i samtal; hur det institutionella samtalets särdrag påverkar konversationen. Sammanfattningsvis visar denna avhandling på att hur medborgarskap praktiseras är situationsbaserat och varierar beroende på vilka som deltar i mötet. Biståndshandläggare kan underlätta för personer med demenssjukdom att övervinna kommunikativa problem genom att använda olika samtalsstrategier och göra det möjlig för dem att delta eller att åtminstone inkluderas i förhandlingen angående olika stödinsatser. Personer med demenssjukdom positioneras ofta som mindre kompetenta än andra personer som deltar i behovsbedömningssamtal, vilket kan medföra konsekvenser på personens delaktighet i planerandet av framtida insatser. Berättelser i dessa samtal positionerar ofta personen med demenssjukdom som beroende av andra, vilket kan underminera deras identitet och uppfattning av sig själva.

In the present investigation peripheral blood lymphocytes from patients with inflammatory bowel disease (IBD) and different cancer states were treated with various agents and compared with lymphocytes from healthy control individuals (HCI) treated in the same way and measured in the Comet assay. For inflammatory bowel disease, patient's responses in IBD patients treated with H2O2 were higher than in HCI and Crohn's patients (CD) were found to have higher responses than Ulcerative colitis (UC) patients. The responses for all IBD and HCI were all reduced in the presence of chaga mushroom extract which behaved in an antioxidant manner. A second group of IBD patients were treated with the heterocyclic amine (food mutagen), IQ and H2O2 and responses were reduced in the presence of the flavonoids, quercetin and epicatechin and compared with HCI similarity treated. In all cells responses were reduced with flavonoids and again CD had higher responses than the UC patients and IBD patients higher than HCI. The responses with CD and UC were that confirmed in two independent studies with IBD, one with chaga mushroom extract and the other with flavonoids. Peripheral lymphocytes from malignant melanoma and suspected melanoma patients and colon cancer and polyposis patients were compared to the lymphocytes from HCI and treated with UVA. There were differential sensitivities when measured in the micronucleus and Comet assays. The cancer patients had higher responses than those in the precancerous states and they in turn were higher than responses in HCI. In all the studies, untreated baseline DNA damage values were also higher in IBD and cancer patients and pre-cancerous patients than HCIs. This would suggest that baseline frequencies of different diseases compared to controls could be an important biomarker in the diagnosis of pre-cancers and early stage cancers. Also peripheral lymphocytes are a useful surrogate for cancers and pre-cancerous disease states since, blood is present in all organs and tissues and DNA is basically the same in all cells.

Les mélanomes malins (MM) constituent le deuxième type de cancer le plus fréquent chez les jeunes adultes canadiens (entre 20 et 44 ans) ainsi qu’un des rares cancers dont l’incidence augmente annuellement. À moins que les MM ne soient excisés à temps par chirurgie, les chances de survie des patients sont pratiquement nulles puisque ce type de tumeur est très réfractaire aux traitements conventionnels. Il est bien connu que l’exposition aux rayons ultraviolets (UV), induisant des photoproduits génotoxiques, est une déterminante majeure dans l’acquisition de MM. À cet effet, la réparation par excision de nucléotides (NER) est la ligne de défense principale contre le développement des mélanomes puisqu’elle est la voie de réparation prépondérante en ce qui a trait aux dits photoproduits. Malgré cela, la contribution potentielle de défauts de la NER au développement des MM dans la population normale n’est toujours pas bien établie. Notre laboratoire a précédemment développé une méthode basée sur la cytométrie de flux qui permet de mesurer la NER en fonction du cycle cellulaire. Cette méthode a déjà mise en évidence qu’une déficience de l’activité de la protéine ATR peut mener à une déficience de la NER exclusive à la phase S dans des fibroblastes humains. Pareillement, nous avons démontré que plusieurs lignées cellulaires cancéreuses modèles comportent une déficience en NER en phase S, suggérant qu’une telle déficience puisse caractériser certains types de cancers. Nous avons voulu savoir si une déficience en NER en phase S pouvait être associée à une proportion significative de mélanomes et si le tout pouvait être attribuable à une diminution de l’activité d’ATR. Nos objectifs ont donc été de : (i) mesurer l’efficacité de la NER en fonction du cycle cellulaire dans les MM en comparaison avec les mélanocytes primaires, (ii) vérifier si le niveau d’activité d’ATR corrèle avec l’efficacité de la NER en phase S dans les lignées de MM et (iii) voir si un gène fréquemment muté dans les mélanomes (tels PTEN et BRAF) pouvait coopérer avec ATR pour réguler la NER en phase S dans les mélanomes. Nous avons démontré que 13 lignées de MM sur 16 ont une capacité grandement diminuée à réparer les photoproduits induits par UV spécifiquement en phase S. De plus, cette déficience corrèle fortement avec une réduction de l’activation d’ATR et, dans plusieurs lignées de MM, avec une phosphorylation d’Akt plus importante. L’utilisation d’ARN interférent ou d’un inhibiteur du suppresseur de tumeurs PTEN, a permis, en plus d’augmenter la phosphorylation d’Akt, de réduire la réparation des photoproduits et l’activation d’ATR dans les cellules en phase S. En addition, (i) l’expression ectopique de la protéine PTEN sauvage dans des lignées déficientes en PTEN (mais pas d’une protéine PTEN sans activité phosphatase) ou (ii) l’inhibition pharmacologique d’Akt a permis d’augmenter la réparation en phase S ainsi que l’activation d’ATR. En somme, cette étude démontre qu’une signalisation d’ATR dépendante de PTEN/Akt amenant à une réparation déficiente des photoproduits génomiques causés par les UV en phase S peut être déterminante dans le développement des mélanomes induits par UV. / Malignant melanoma (MM) is the second most frequent neoplasia among young Canadian adults (aged 20-44); moreover the incidence of this disease continues to rise annually at an alarming rate. Unless primary melanoma is diagnosed early and promptly resected the patient prognosis is dismal since this deadly tumour type metastasizes extremely aggressively and is highly refractory to conventional treatment protocols. It is well established that exposure to UV light, and subsequent induction of genotoxic DNA photoproducts, is a primary determinant in the initiation of MM. Furthermore nucleotide excision repair (NER) clearly represents a critical frontline defence against MM because it is the only human pathway designed to remove the aforementioned DNA photoproducts. Despite this, the potential contribution of NER defects to sporadic MM development in the general population has remained unclear. Our laboratory previously developed a novel flow cytometry-based assay to evaluate the efficiency of NER as a function of cell cycle. This method was employed to demonstrate that functional ATR kinase is strictly required for NER during S phase in primary human fibroblasts. Intriguingly we also reported that many model tumour cell lines are deficient in NER uniquely in S phase populations, raising the possibility that such a defect might be characteristic of certain types of cancers. We therefore hypothesized that a significant proportion of human MM cell lines may exhibit reduced NER capacity specifically during S phase, and that this in turn might be attributeable to reduced ATR signaling. To test this hypothesis, three major specific aims were proposed: (i) To measure the efficiency of NER as a function of cell cycle among a panel of human MM cell lines and in primary melanocytes; (ii) To investigate whether any correlation exists between NER status and ATR activity during S phase in human MM cell lines; (iii) To investigate whether frequently mutated genes in melanoma (eg., PTEN, BRAF) might cooperate with ATR to regulate S phase-specific NER in MM cell lines. We were able to demonstrate that, in fact, 13/16 MM cell lines display remarkably diminished capacity to remove UV-induced DNA photoproducts specifically during S phase. Furthermore this defect correlates strongly with reduced activation of ATR kinase and, for a majority of MM, higher Akt phosphorylation levels. RNAi-mediated knockdown of the PTEN tumour suppressor, while stimulating Akt phosphorylation as expected, also engenders reductions in both photoproducts repair and ATR activation in S phase cells. In addition, (i) ectopic expression in PTEN-null strains of wild type PTEN but not of PTEN variants deficient in phosphatase activity, or (ii) pharmacological inhibition of Akt, significantly rescue S phase-specific repair as well as ATR activation. Our data indicate that reduced PTEN/Akt-dependent ATR signaling leading to defective repair of UV DNA photoproducts uniquely during S phase may represent an heretofore unrecognized major determinant in sunlight-induced melanoma development.

The energy metabolism of most tumor cells relies on aerobic glycolysis (Warburg effect) characterized by an increased glycolytic flux that is accompanied by the increased formation of the cytotoxic metabolite methylglyoxal (MGO). Consequently, the rate of detoxification of this reactive glycolytic byproduct needs to be increased in order to prevent deleterious effects to the cells. This is brought about by an increased expression of glyoxalase 1 (GLO1) that is the rate-limiting enzyme of the MGO-detoxifying glyoxalase system. Here, we overexpressed GLO1 in HEK 293 cells and silenced it in MCF-7 cells using shRNA. Tumor-related properties of wild type and transformed cells were compared and key glycolytic enzyme activities assessed. Furthermore, the cells were subjected to hypoxic conditions to analyze the impact on cell proliferation and enzyme activities. Our results demonstrate that knockdown of GLO1 in the cancer cells significantly reduced tumor-associated properties such as migration and proliferation, whereas no functional alterations where found by overexpression of GLO1 in HEK 293 cells. In contrast, hypoxia caused inhibition of cell growth of all cells except of those overexpressing GLO1. Altogether, we conclude that GLO1 on one hand is crucial to maintaining tumor characteristics of malignant cells, and, on the other hand, supports malignant transformation of cells in a hypoxic environment when overexpressed.

Malignant pleural mesothelioma (MPM) is a form of aggressive tumour that is almost always associated with prior exposure to asbestos. Currently responsible for over 47,000 deaths worldwide each year and rising, it poses a serious threat to global public health. Many clinical studies of MPM, including its diagnosis, prognostic planning, and the evaluation of a treatment, necessitate the accurate quantification of tumours based on medical image scans, primarily computed tomography (CT). Currently, clinical best practice requires application of the MPM-adapted Response Evaluation Criteria in Solid Tumours (MPM-RECIST) scheme, which provides a uni-dimensional measure of the tumour's size. However, the low CT contrast between the tumour and surrounding tissues, the extensive elongated growth pattern characteristic of MPM, and, as a consequence, the pronounced partial volume effect, collectively contribute to the significant intra- and inter-observer variations in MPM-RECIST values seen in clinical practice, which in turn greatly affect clinical judgement and outcome. In this thesis, we present a novel computer-assisted approach to evaluate MPM patient response to treatments, based on the volumetric segmentation of tumours (VTA) on CT. We have developed a 3D segmentation routine based on the Random Walk (RW) segmentation framework by L. Grady, which is notable for its good performance in handling weak tissue boundaries and the ability to segment any arbitrary shapes with appropriately placed initialisation points. Results also show its benefit with regard to computation time, as compared to other candidate methods such as level sets. We have also added a boundary enhancement regulariser to RW, to improve its performance with smooth MPM boundaries. The regulariser is inspired by anisotropic diffusion. To reduce the required level of user supervision, we developed a registration-assisted segmentation option. Finally, we achieved effective and highly manoeuvrable partial volume correction by applying a reverse diffusion-based interpolation. To assess its clinical utility, we applied our method to a set of 48 CT studies from a group of 15 MPM patients and compared the findings to the MPM-RECIST observations made by a clinical specialist. Correlations confirm the utility of our algorithm for assessing MPM treatment response. Furthermore, our 3D algorithm found applications in monitoring the patient quality of life and palliative care planning. For example, segmented aerated lungs demonstrated very good correlation with the VTA-derived patient responses, suggesting their use in assessing the pulmonary function impairment caused by the disease. Likewise, segmented fluids highlight sites of pleural effusion and may potentially assist in intra-pleural fluid drainage planning. Throughout this thesis, to meet the demands of probabilistic analyses of data, we have used the Non-Parametric Windows (NPW) probability density estimator. NPW outperforms the histogram in terms of its smoothness and kernel density estimator in its parameter setting, and preserves signal properties such as the order of occurrence and band-limitedness of the sample, which are important for tissue reconstruction from discrete image data. We have also worked on extending this estimator to analysing vector-valued quantities; which are essential for multi-feature studies involving values such as image colour, texture, heterogeneity and entropy.

Le mélanome malin (MM) est un cancer très réfractaire aux thérapies anticancéreuses, dont les vincalcaloïdes (VAs). Afin d'étudier le rôle de la GSTM1 (glutathion S-transférase 1) et la MRP1 (multidrug resistance protein 1) dans la résistance acquise du MM aux VAs, nous avons établi 4 modèles cellulaires de résistance à la vincristine (CAL1R-VCR), à la vindésine (CAL1R-VDS), à la vinorelbine (CAL1R-VRB) et à la vinflunine (CAL1R-VFL), par exposition continue de cellules du MM (CAL1-wt), pendant un an, à ces anticancéreux. L'expression d'ne GSTM1 fonctionnelle est spécifiquement observée (RT-PCR, western blot, activité GST totale) dans les cellules résistantes. Le curcumin (inhibiteur de GSTM1), la BSO (inhibiteur de synthèse de glutathion) et le MK571 (inhibiteur de MRP1), réduisent considérablement le résistance acquise à la VCR et à la VDS mais pas à la VRB ou à la VFL. Toutefois, tous ces VAs réduisent spécifiquement l'activité GSTM1. Ces données montrent l'implication différentielle de GSTM1 et MRP1 dans la résistance aux VAs. Pour déterminer les mécanismes moléculaires de cette chimiorésistance, nous avons réalisé une étude pangénomique (biopuces Affymetrix HG-U133 Plus 2.00) sur les lignées CAL1 (wt et R). Le regroupement hiérarchique (par Cluster et TreeView) des données des puces a révélé une similarité entre les profils d'expression génique de CAL1R-VRB et CAL1-wt mais aussi entre ceux de CAL1R-VCR et CAL1R-VDS. L'analyse bioinformatique (par IPA) des transcrits les plus différemment exprimés entre les lignées cellulaires, a mis en évidence 6 réseaux géniques connus pour leur rôle dans la chimiorésistance tumorale. Le programme FatiGO a révélé 3 termes biologiques sur-représentés (> 60%) dans CAL1R (ribosome, filaments intermédiaires du cytosquelette, récepteurs olfactifs) tandis que l'étude fonctionnelle (invalidation génique par siRNA, test de viabilité) de GPR143, KIT et SLC45A2 (gènes interagissant avec NF-κB et CCND1 (facteurs de la chimiorésistance tumorale), très exprimés dans CAL1-wt et muets dans CAL1R) a montré la faible tendance des deux premiers à être impliqués dans la résistance aux VAs. / Malignant melanoma (MM) is a very refractory tumor to anticancer therapies, including vinca alkaloïds (VAs). To investigate the role of GSTM1 (glutathione S-transferase μ1) and MRP1 (multidrug resistance protein 1) in MM acquired resistance to VAs, we established 4 cellular models of resistance to vincristine (CAL1R-VCR), to vindesine (CAL1R-VDS), to vinorelbine (CAL1R-VRB) and to vinflunine (CAL1R-VFL), by continuous exposure of MM cells (CAL1-wt), for one year, to these anticancer agents. The expression of a functional GSTM1 is specifically observed (RT-PCR, western blot, total GST activity) in resistant cells. Curcumin (GSTM1 inhibitor), BSO (glutathione synthesis inhibitor) and MK571 (MRP1 inhibitor), considerably reduce the acquired resistance to VCR and VDS but not that to VRB or VFL. However, all these VAs specifically reduce GSTM1 activity. These data show the differential involvement of GSTM1 and MRP1 in resistance to VAs. To determine the molecular mechanisms of this chemoresistance, we performed a pangenomic study (Affymetrix HG-U133 Plus 2.00 microarrays) on the CAL1 lines (wt and R). The hierarchical clustering (by Cluster and TreeView) of array data revealed a similarity between the gene expression profiles of CAL1R-VRB and CAL1-wt, but also between those of CAL1R-VCR and CAL1R-VDS. The bioinformatic analysis (by IPA) of the most differentially expressed transcripts between cell lines, highlighted 6 gene networks known for their role in tumor chemoresistance. FatiGO program revealed 3 biological terms overrepresented (>60%) in CAL1R (ribosome, intermediate filaments of cytoskeleton, olfactory receptors), while functional study (gene invalidation by siRNA, viability test) of GPR143, KIT and SLC45A2 (genes interacting with NF-kB and CCND1 (tumor chemoresistance factors), highly expressed in CAL1-wt and mute in CAL1R) showed the weak trend of the two formers to be involved in resistance to VAs.

Cancer is a leading cause of death in the western world and is increasing in frequency world-wide. Although diagnosis, treatment and therapeutic approaches to cancer have improved, many types of cancer are still lethal due to the lack of radical treatment. One of the fatal neoplastic disease types with poor prognosis is represented by malignant mesothelioma (MM). MM is characterised by very high mortality rate and limited therapeutic options. The etiology of the disease is mainly associated with exposure to asbestos fibres. The incidence of MM is increasing in many countries. The search for novel molecular targets, anti-cancer strategies and drugs, which would considerably improve the treatment is of great importance. Certain new drugs, especially those with specific molecular targets, show high selectivity in their action to cancer cells, and have considerably increased the cure rate in some types of cancer. Mitochondria have recently emerged as a very promising target for anti-cancer agents. A group of compounds with anti-cancer activity that induce apoptosis by way of mitochondrial destabilisation, termed 'mitocans', have been a recent focus of research. Several mitocans have been shown to selectively induce apoptosis in cancer cells and suppress the growth of many types of carcinomas in...