1 |
Combining Noxa-Inducing Drugs with ABT-263 to Efficiently Increase Cell Death in Head and Neck Squamous Cell Carcinoma (HNSCC)Kim, Sung Woo 01 January 2017 (has links)
Head and neck cancer is the sixth leading cancer worldwide. Head and neck squamous cell carcinoma (HNSCC) accounts for more than 90% of incident cases. Despite intense, multimodality treatment regimens for HNSCC including surgery, chemotherapy, and radiation, little progress has been made over the past 30 years in improving overall survival rates. Tumor cell death induced by both conventional and targeted chemotherapy is often mediated by the BCL-2 family-dependent mitochondrial apoptotic pathway. However, initiators of this apoptotic pathway, such as p53, are more than 50% of the time mutated or deleted in HNSCC rendering the disease refractory to treatment. To counter such resistance, direct therapeutic targeting of the BCL-2 family is conceptually appealing. For this purpose, we use three clinically-available drugs: cisplatin, fenretinide, and ABT-263 (navitoclax). Both cisplatin and fenretinide are known to induce a BH3-only pro-apoptotic protein, Noxa, which binds to and inactivates multi-domain anti-apoptotic protein MCL-1 and release from its interaction with multi-domain pro-apoptotic protein BAK, followed by the phosphorylation via CDK2 for the proteasome-mediated degradation. Activated BAK can now go through conformational change for the oligomerization at the outer membrane of the mitochondria to release cytochrome c into the cytosol and induce caspase-dependent apoptotic cell death. ABT-263 directly binds to multi-domain anti-apoptotic proteins, such as BCL-2 and BCL-XL, to inhibit their activity and leads to the activation of multi-domain pro-apoptotic protein BAX to induce apoptosis.
We hypothesize that combining the Noxa-inducing drugs (cisplatin or fenretinide) along with ABT-263 can efficiently induce BAX and BAK activation and significantly increase cell death in HNSCC cells by simultaneously inhibiting the activity of MCL-1, BCL-2, and BCL-XL. Combination-induced treatments in four cell lines (HN8, HN30, HN31, and UMSCC1) tested led to significant increase in apoptotic cell death. Cisplatin and ABT-263 combined treatment is inducing the expression of Noxa and leading to increase in apoptosis in HN30, HN31, UMSCC1, but not HN8. Similarly, fenretinide and ABT-263 combined treatment is inducing the expression of Noxa in all four cell lines tested and is largely relying on expression of Noxa.
|
2 |
Targeting BCL-2 Family Members in the Cell Death Pathway to Treat Head and Neck CancerBritt, Erin L 01 January 2018 (has links)
Head and neck cancer accounts for approximately 3 percent of all cancers in the United States, and over 90% of them are head and neck squamous cell carcinoma (HNSCC). Chemotherapeutic drugs that treat HNSCC can activate BCL-2 family dependent apoptosis. Pro-apoptotic NOXA induced by adenovirus (Ad-NOXA) or fenretinide inactivates anti-apoptotic MCL-1, while ABT-263 can inactivate other anti-apoptotic BCL-2 family members such as BCL-2 and BCL-XL. We used p53 inactive HN8 and HN12, p53 wild-type UMSCC1, and HPV-positive UMSCC47 human HNSCC cell lines and five mouse HNSCC cell lines. Cells were treated with Ad-NOXA, ABT-263, and fenretinide alone or in combinations. Combinational treatment of ABT-263 with Ad-NOXA or fenretinide enhanced cell death among all cell lines we tested regardless of p53 status. These findings support the hypothesis that combinational treatment of Ad-NOXA or fenretinide with ABT-263 increases cell death by simultaneously inhibiting all anti-apoptotic BCL-2 family proteins in HNSCC cells.
|
3 |
The Effect of Noxa Serine-13 Phosphorylation on Hyperthermia-Induced ApoptosisMorey, Trevor 13 February 2012 (has links)
Regulation of apoptosis is critical for cell survival during mild stress and for proper removal of damaged cells during severe stress including hyperthermia. Previous studies have shown that knockdown of the BH3-only protein Noxa prevents hyperthermia-induced Mcl-1 degradation and activation of apoptosis. Noxa is a pro-apoptotic BH3-only protein that is able to selectively bind to and disable anti-apoptotic Mcl-1. Phosphorylation of Noxa on serine-13 by the cyclin-dependent kinase CDK5 inhibits the apoptotic function of Noxa. In this study I investigated whether hyperthermia is able to induce apoptosis by preventing Noxa phosphorylation, due to reduced CDK5 activity, leading to activation of Noxa. I was able to demonstrate that both the phosphorylation status and solubility of CDK5 is reduced during hyperthermia. Furthermore, overexpression of a non-phosphorylatable Noxa (S13A) resulted in a significant decrease in cell viability and increase in caspase-3 activity compared to overexpression of wild-type Noxa at 37°C. However, I was unable to detect in vivo phosphorylation of Noxa serine-13 in lymphoid cells and therefore was unable to conclude whether or not hyperthermia affects the phosphorylation status of Noxa.
|
4 |
The Role of Noxa/MCL-1 in Head and Neck Squamous Cell Carcinoma (HNSCC) TreatmentLee, June Young 01 January 2015 (has links)
Head and neck cancer is the sixth leading type of cancer with 90 percent of head and neck cancer arising from squamous cell lining on the epithelium of the oral and nasal cavity, pharynx, and salivary gland. Even with tremendous achievements on chemotherapeutic drugs and therapies, the long-term prognosis of patients with advanced head and neck squamous cell carcinoma (HNSCC) has shown little improvement over the last three decades. Cisplatin is one of widely used chemotherapeutic drugs for multiple
cancers, including head and neck cancer, but the prolonged use of this drug is limited by its toxicity and by the development of resistance. To overcome these major roadblocks to improved prognosis requires mechanism-based therapeutic strategies to maximize the antitumor effect of drugs while limiting their toxicities. Cisplatin exerts anticancer effects via multiple mechanisms, yet its most prominent mode of action involves the generation of DNA lesions followed by the activation of the DNA damage response and the induction of BCL-2 family-dependent mitochondrial apoptosis. DNA damage activates a tumor suppressor p53 to induce apoptosis. One of its functions is to induce the expression of several pro-apoptotic proteins such as Noxa, which binds to an anti-apoptotic BCL-2 family protein, MCL-1 (myeloid leukemia cell-1) to inactivate its pro-survival function and induce apoptosis. We examined Noxa expression and apoptosis induced by cisplatin in p53-wild-type HN30 and HN31, p53-truncated and inactive HN4 and HN12, and p53-deleted HN22 and HN8 HNSCC cell lines. We found that Noxa was induced in HN30 and HN31 cells and down-regulation of Noxa by shRNA (short-hairpin RNA) decreased apoptosis, indicating Noxa contribution to cisplatin-induced apoptosis. Interestingly, cisplatin treatment induced Noxa and apoptosis even in p53-deleted HN22 and HN8 cells, suggesting the existence of the p53-independent pathways for the induction of Noxa. Based on these observations, we hypothesized that modulation of Noxa/MCL-1 axis could mimic cisplatin-induced cell death. We found that Noxa overexpression induced cell death in all cell lines tested regardless of p53 status. This finding could be applicable as a potential therapeutic strategy to treat head and neck cancer.
|
5 |
"BH3-only" Noxa, cible spécifique de l'induction d'apoptose pour la thérapie des leucémies lymphoïdes chronique / The protein "bh3-only" noxa, specific target of the apoptosis induction for the therapy of the chronic lymphocytic leukemiaZaher, Murhaf 02 September 2011 (has links)
La Leucémie Lymphoïde Chronique (LLC) est caractérisée par l’accumulation dans le sang de lymphocytes B/CD5+ qui sont déficients pour leur programme de mort apoptotique. Malgré les progrès thérapeutiques récents, la LLC est une maladie toujours incurable. La stratégie de rétablissement des processus apoptotiques semble pertinente pour améliorer les traitements des patients, et cette stratégie nécessite l’identification de cibles spécifiques. Dans ce but, nous avons développé une recherche du mécanisme d’action de l’hyperforine, un phloroglucinol purifié à partir de la plante Millepertuis, qui est un inducteur d’apoptose des cellules de LLC ex vivo par la voie mitochondriale dépendante des caspases. Les résultats montrent que le traitement des cellules primaires de LLC régule positivement Noxa, une protéine de la famille Bcl-2 du type « BH3-only » qui est un ligand antagoniste spécifique de Mcl-1, la protéine de survie majeure pour le défaut d’apoptose dans les LLC. Nous montrons que Noxa interagit effectivement avec Mcl-1, ce qui entraine la dissociation du complexe que Mcl-1 forme avec Bak, et l’activation de cette protéine responsable de la libération par la mitochondrie des facteurs d’activation des caspases. La régulation positive de Noxa ne résulte apparemment pas d’une activation transcriptionnelle mais plutôt d’une régulation au niveau protéique comme le suggère la capacité de l’hyperforine à inhiber l’activité protéolytique du protéasome dans les cellules de LLC. Par ailleurs, l’apoptose induite par l’hyperforine est réduite en partie par l’extinction de Noxa avec des ARN interférents. Nos résultats indiquent donc que la régulation positive de Noxa est un des mécanismes qui permet à l’hyperforine de déclencher l’apoptose des cellules de LLC. Ce mécanisme semble être commun à d’autres composés d’origine végétale, comme nous l’avons observé avec l’extrait M2Yn dans la seconde partie de notre travail qui a permis de mettre en évidence que cet extrait de plantes d’Asie centrale est capable lui aussi d’induire l’apoptose des cellules de LLC par la voie mitochondriale dépendante des caspases. Enfin, nous avons contribué à la mise en évidence des propriétés pro-apoptotiques de l’hyperforine dans un autre modèle de leucémie, la leucémie myéloïde aiguë, grâce en partie à la régulation positive de Noxa ainsi qu’à l’inhibition de l’activité kinasique de Akt-1.En conclusion, nos travaux de thèse décrivent des nouvelles étapes dans le mécanisme d’action de l’hyperforine et permettent d’établir que la protéine « BH3-only » Noxa est une cible majeure pour la stratégie thérapeutique du rétablissement d’apoptose dans les LLC, ce qui devrait susciter le développement de nouveaux agents capables d’imiter spécifiquement l’action de Noxa. / Chronic lymphocytic leukemia (CLL) is characterized by blood accumulation of CD5+/B lymphocytes which are deficient in their apoptotic program. Despite recent therapeutic advances, CLL remains an incurable disease. Treatment strategy based on the re-establishment of apoptotic processes has retained much attention, and such a strategy requires the identification of specific targets. To this aim, we have investigated the mechanism of action of hyperforin, a phloroglucinol purified from St John’s wort, capable of inducing apoptosis of CLL cells ex vivo via the caspase-dependent mitochondrial pathway. Our results show that treatment of CLL patients’ cells upregulates the BH3-only protein Noxa that is a specific antagonist ligand of Mcl-1, the crucial prosurvival protein for apoptosis deficiency in CLL. We find that hyperforin provokes both the interaction of Noxa with Mcl-1 and the dissociation of Mcl-1/Bak complex, leading to Bak activation responsible for the release of apoptogenic factors from mitochondria. Noxa upregulation does not seem to result from transcription activation but rather from a regulation at the protein level, as suggested by the ability of hyperforin to inhibit proteasome activity in CLL cells. Using siRNA, Noxa silencing partially reduces hyperforin-induced apoptosis. Our data indicate that Noxa upregulation is one of the mechanisms through which hyperforin triggers CLL cell apoptosis. This mechanism appears to be shared with other plant-derived compounds, as observed with M2Yn, an extract from central Asia plants, that we show here to be an inducer of apoptosis in CLL cells by activating the caspase-dependent mitochondrial pathway. Finally, we have participated in highlighting the proapoptotic properties of hyperforin in another leukemia model, acute myeloid leukemia, via in part Noxa upregulation and Akt1 kinase activity inhibition.In conclusion, our data describe new steps in the mechanism of action of hyperforin and favor that the BH3-only protein Noxa is a major target for the therapeutic strategy based on apoptosis induction in CLL. Thus, this thesis should prompt the development of new BH3 mimetics specific for Noxa.
|
6 |
Regulation des mitochondrialen Apoptosesignalwegs durch BH3-only Proteine und Bcl-2 InhibitorenGebhardt, Nina 27 November 2009 (has links)
In Tumoren führt die Deregulation von Proteinen der Bcl-2 Familie zur Apoptoseresistenz. Diese kann aus einem Verlust der pro-apoptotischen Proteine Bax bzw. Bak, einer Hochregulation von anti-apoptotischen Bcl-2 Proteinen oder aus einer Inaktivierung von BH3-only Proteinen heraus erfolgen. BH3-only Proteine sequestrieren anti-apoptotische Bcl-2 Proteine und induzieren dadurch die Aktivierung von Bax bzw. Bak. Ziel der vorliegenden Arbeit war daher, die Regulation von Apoptose durch das pro-apoptotische BH3-only-Protein Noxa zu untersuchen. Zusätzlich sollte der Mechanismus der Apoptoseinduktion durch niedermolekulare Bcl-2 Inhibitoren in Tumorzellen untersucht werden. Hier wird gezeigt, dass die putativen Bcl-2 Inhibitoren Gossypol, HA14-1 und zum Teil BH3I-2 unabhängig von Bax und Bak Zelltod induzierten. Dies weist darauf hin, dass die Apoptoseinduktion durch diese niedermolekularen Substanzen zumindest teilweise "off-target" ist, d.h. unabhängig von den Zielstrukturen der Bcl-2 Familie erfolgt. Eine andere Strategie zur Aktivierung des mitochondrialen Apoptosewegs ist die Expression von BH3-only Proteinen. Zunächst wurde die Expression putativer Spleißvarianten des Noxa-Gens auf mRNA- und Proteinebene durchgeführt. Hierbei wurde das bekannte BH3-only Protein Noxa als kurze Spleißvariante (NoxaS) und eine bisher unbekannte, lange Spleißvariante (NoxaL) gefunden. Zur funktionellen Analyse wurden konditionale Expressionsvektoren für beide Noxa-Varianten hergestellt. Die Expression von NoxaS führte zu einer differenziellen Aktivierung von Bak und/oder Bax. NoxaL hingegen verfügt über keine BH3-Domäne, induzierte aber dennoch Apoptose in einem Prostatakarzinom-Zelllinienmodell. Weitergehende Untersuchungen zeigten, dass es hier zu einer BH3-unabhängigen Aktivierung eines Bak-vermittelten Zelltod-Signalwegs kommt. Die vorliegende Arbeit liefert somit neue Erkenntnisse zur Zelltodregulation und experimentellen Apoptoseinduktion über BH3-unabhängige Signalmechanismen. / In many tumors deregulation of Bcl-2 family proteins lead to apoptosis resistance. This deregulation can occur through the loss of pro-apoptotic proteins Bax respectively Bak, through upregulation of anti-apoptotic Bcl-2 proteins or from the inactivation of BH3-only proteins. BH3-only proteins sequester anti-apoptotic Bcl-2 proteins and hereby activate Bax and Bak. Therefore aim of the present work was to study the regulation of apoptosis by the pro-apoptotic BH3-only protein Noxa. In addition the mechanism of apoptosis induction in different tumor cells by small molecular substances mimicking the function of BH3-only proteins ought to be investigated. Here we show that the putative Bcl-2 inhibitors Gossypol, HA14-1 and partly BH3I-2 induce cell death independent from Bax and Bak. This shows that the induction of apoptosis by these substances is at least partly off target, i.e. occurs independent of the target structures of the Bcl-2 family. Another strategy to activate the mitochondrial signaling pathway is the expression of BH3-only proteins. Initially the expression of putative splicing variants of the noxa gene was carried out on mRNA and protein level. Here the known NoxaS as short splicing variant (NoxaS) and an up to that point unknown long splicing variant (NoxaL) have been found. For functional analysis of the two splicing variants conditional expression vectors have been generated. The overexpression of NoxaS led to a differential activation of Bax and/or Bak. However NoxaL does not contain a BH3 domain but still induced apoptosis in a prostate carcinoma cell system. Advanced studies showed a BH3 independent activation of a Bak mediated cell death signaling pathway. The present work therefore provides new insights into cell death regulation and experimental apoptosis induction via BH3 independent signaling mechanisms.
|
7 |
La representación de mujeres en la literatura ecológica: ¿Con una agencia transcorpórea? : Una comparación ecofeminista entre las novelas Mugre Rosa y Noxa / The representation of women in ecological literature: With a transcorporeal agency? : An ecofeminist comparison of the novels Mugre Rosa and NoxaKarlsson, Sofia January 2023 (has links)
Las crecientes preocupaciones sobre el cambio climático y una creciente crisis ecológica se están volviendo cada vez más visibles en la literatura de diferentes géneros, especialmente en la literatura postapocalíptica y "cli-fi" (literatura sobre cambio climático). Reconociendo que el desastre ecológico afecta a las mujeres de manera desproporcionada, esta tesina emplea un análisis literario ecofeminista para examinar dos novelas en las que la trama principal está impulsada por una crisis ecológica causada por la contaminación. Más específicamente, esta tesina investiga la novela Mugre Rosa de Fernanda Trías (2021) y la novela Noxa de María Inés Krimer (2016), para descubrir qué estrategias utilizan las protagonistas femeninas para enfrentar sus situaciones peligrosas y cómo esto moldea su agencia desde un punto de vista ecofeminista. La tesis encuentra que las protagonistas de ambas novelas emplean varias estrategias para sobrevivir y a veces resistir la crisis ecológica que las rodea, pero también muestran momentos de apatía, rabia e inacción. Hay diferencias significativas entre las novelas, donde la protagonista de Noxa es retratada como más activa en la lucha contra la crisis y la protagonista de Mugre Rosa es más apática y furiosa. Esto se discute luego en términos de agencia transcorpórea y vulnerabilidad insurgente (Alaimo 2008, 2009). Finalmente, la tesina también discute de qué manera estas representaciones pueden transmitir unas preocupaciones ecofeministas al lector. Argumenta que muchas preocupaciones ecofeministas son visibles en ambas novelas, que van desde una crítica al capitalismo patriarcal hasta el control de los cuerpos femeninos, pasando por cuestiones de maternidad y monstruosidad, hasta finalmente la relación entre los seres humanos y la naturaleza. Esto demuestra la necesidad de un análisis más profundo de las preocupaciones ecológicas en la literatura, lo cual es probable que se vuelva cada vez más presente en estos tiempos. / Rising concerns about climate change and a mounting ecological crisis are becoming increasingly visible in literature of different genres, especially in post-apocalyptic and ‘cli-fi’ literature. Recognising that ecological disaster often disproportionally affects women, this thesis employs an ecofeminist literary analysis to examine two such novels where the main plot is driven by an ecological crisis caused by pollution. More specifically, this thesis investigates the novel Mugre Rosa by Fernanda Trías (2021) and the novel Noxa by María Inés Krimer (2016), to find out what strategies the female protagonists use to confront their perilous situations and how this shapes their agency from an ecofeminist standpoint. The thesis finds that protagonists in both novels employ various strategies to survive and sometimes resist the ecological crisis that surrounds them, but also show moments of apathy, rage and inaction. There are significant differences between novels, where the protagonist of Noxa is portrayed as more active in fighting against the crisis and the protagonist of Mugre Rosa is more apathetic and raging. This is then discussed in terms of transcorporeal agency and insurgent vulnerability (Alaimo 2008, 2009). Finally, the thesis also discusses in what ways these representations can convey ecofeminist concerns to readers. It argues that many ecofeminist concerns are visible in both novels, ranging from a criticism of patriarchal capitalism to the control of female bodies to issues of maternity and monstrosity to finally the relationship between humans and nature. This shows a need for further analysis of ecological concerns in literature, which is likely to become ever more present in these times.
|
8 |
Structural Studies of Soluble Guanylyl Cyclase and Its Bacterial HomologsMA, Xiaolei 18 April 2008 (has links)
No description available.
|
9 |
Tumor-Specific Cell Death Induction by Noxa Overexpression for Head and Neck Squamous Cell Carcinoma (HNSCC) TreatmentMaxim, Nicolas T, Mr. 01 January 2016 (has links)
The primary focus of this research is the mechanisms of cell death in head and neck squamous cell carcinoma (HNSCC) treatment. These cancers typically originate in squamous cells that line the moist mucosal surfaces of head and neck. HNSCC is commonly treated with a platinum based agent, cisplatin. While the drug does offer strong antitumor effects, its prolonged use often results in tumor-acquired resistance, which limits treatment effectiveness. We have shown that cisplatin treatment induces the expression of a pro-apoptotic BCL-2 family member Noxa, which then initiates caspase- dependent apoptosis through its binding and sequestration of pro-survival protein MCL-1 for its inactivation. Without Noxa induction, cell death is significantly reduced when treating HNSCCs with cisplatin. The objectives of this study are (1) to determine the molecular mechanisms by which Noxa induces cell death in HNSCC cells; (2) to determine the molecular mechanisms of cisplatin-resistance in isogenic HNSCC cell lines.
We observed an increase of apoptosis by ectopic expression of Noxa in all HNSCC cell lines tested, but not in immortalized human normal oral keratinocytes (NOK), suggesting that Noxa overexpression is sufficient to induce tumor-specific cell death. Noxa-induced cell death was mediated by BAX and BAK activation. BAK activation was mediated through Noxa binding to MCL-1, but not BCL-XL. Cisplatin- resistant cells induced less Noxa and apoptosis, supporting that Noxa induction is prerequisite for apoptosis induced by cisplatin. Taken together, Noxa induces tumor- specific cell death in HNSCC cells primarily through BAX and BAK activation, which suggests the therapeutic potential of this protein.
|
10 |
Études multiparamétriques de biomarqueurs par immunofluorescence pour mieux suivre la progression du cancer de la prostateClairefond, Sylvie 12 1900 (has links)
Le cancer de la prostate est le cancer le plus fréquemment diagnostiqué et la troisième cause de mortalité liée au cancer chez les hommes au Canada. Un quart des patients diagnostiqués développeront une forme plus agressive de ce cancer. Bien que nous possédions plusieurs indices cliniques pronostiques dans les cancers localisés (score de Gleason, taux sérique d’antigène prostatique spécifique (APS), stade, etc.), ceux-ci sont insuffisants pour adéquatement distinguer les patients à faible risque de progression de ceux à haut risque. A ce jour, aucun biomarqueur pronostique n’est encore utilisé en clinique. Les cliniciens ont donc besoin de nouveaux outils plus efficaces pour stratifier ce cancer et pour s’assurer d’adapter au mieux le traitement à chaque patient.
En nous basant sur la littérature et sur des études préliminaires (cohortes de moins de 65 patients), notre hypothèse est que les protéines PUMA-NOXA et les récepteurs membranaires de la famille ERBB seraient, lorsqu’utilisés en combinaison, des biomarqueurs prédictifs de la progression du cancer de la prostate. Les objectifs de cette thèse sont : 1) identifier et valider de bons anticorps pour chaque biomarqueur d’intérêt, 2) définir les niveaux d’expression de chaque biomarqueur sur une cohorte de 285 patients, et 3) établir les corrélations entre les niveaux d’expression et les données cliniques des patients.
Dans l’optique d’une utilisation en clinique, des anticorps de type monoclonal ont été choisis pour identifier les biomarqueurs d’intérêts. Ces anticorps ont été testés et validés pour leur spécificité par immunobuvardage de type western blot et par immunofluorescence. La localisation de la protéine d’intérêt a été validée sur des échantillons de tissus de patients suivie de l’optimisation du multi-marquage sur les cellules épithéliales et basales. Après perfectionnement de l’analyse d’images, nous avons montré qu’une expression extrême (faible ou forte) de PUMA couplée à une forte expression de NOXA dans les glandes bénignes est associée à la rechute biochimique des patients. La présence de ces biomarqueurs dans les glandes bénignes permet d’envisager d’améliorer l’identification lors des premières biopsies des patients se qualifiant pour la surveillance active. Par ailleurs, le suivi de l’expression des récepteurs de la famille ERBB dans les glandes tumorales permet une stratification des patients atteints d’un cancer de la prostate en fonction des risques de rechute biochimique, de développement de métastases et de mort liée au cancer. Ainsi, les patients présentant la combinaison d’une forte expression de EGFR et d’une faible expression de ERBB3 sont les plus susceptibles de mourir spécifiquement de leur cancer de la prostate, en particulier si les cellules tumorales présentes en plus une faible expression de ERBB2 entrainant un fort risque de développer des métastases.
Mon projet de doctorat aura donc permis d’identifier et de valider des biomarqueurs d’intérêt pour prédire l’évolution du cancer de la prostate et démontrer l’intérêt de suivre ces biomarqueurs en combinaison afin d’obtenir une meilleure stratification des patients. Ces résultats devront être validés sur une cohorte indépendante et multicentrique en vue de fournir aux cliniciens un plus grand nombre d’outils pour leur permettre de réaliser une stratification fine des patients atteints d’un cancer de la prostate, et ouvrirait la voie à de nouvelles stratégies thérapeutiques plus ciblées. / Prostate cancer is the most frequently diagnosed cancer and the third leading cause of cancer-related death in men in Canada. A quarter of patients will develop a more aggressive form of this cancer. While there are several clinical prognostic variables for localized prostate cancer (Gleason score, prostate specific antigen (PSA) levels, stage, etc.), these are insufficient to adequately distinguish between low and high-risk of progression cases. As a result, clinicians need new, more effective tools to stratify this cancer and to ensure that treatments are best tailored to each patient. To date, no prognostic biomarker has yet been used clinically.
Based on the literature and preliminary studies of small cohorts (less than 65 patients), we hypothesize that the protein expression of PUMA-NOXA and ERBB family members could help with the prediction of prostate cancer progression. The objectives of this thesis are: 1) to identify and validate antibodies for each biomarker of interest, 2) to define the expression levels of each biomarker on a 285 patient cohort, 3) to evaluate the correlation between marker expression levels and patient clinical data.
For clinical use, monoclonal-type antibodies were chosen to identify the biomarkers of interest. These antibodies were validated for specificity by western blot and immunofluorescence techniques. The localization of the protein of interest was further identified within samples of patient tissues and additional optimization involving combinatorial staining for epithelial and basal cells. After refining the imaging and statistical analysis of PUMA and NOXA in benign glands, we found that extreme (weak or strong) PUMA expression coupled with high NOXA expression was associated with biochemical relapse. In addition, these proteins have significant potential for predicting disease evolution based on the initial radical prostatectomy sample. The presence of these proteins in benign glands would allow the identification of patients less suitable for active surveillance. Additionally, statistical analysis of ERBB family receptors in tumor glands, when used alone, allow stratification of prostate cancer patients for the prediction of biochemical relapse, development of metastases and also specific death from prostate cancer. Moreover, patients expressing a combination of high EGFR expression and low ERBB3 expression are at high risk of biochemical relapse and are at higher risk of prostate cancer specific mortality. In addition, coupling this high EGFR – low ERBB3 combination to a low ERBB2 expression helps classify patients at high risk of developing metastases.
My doctoral research project will have made it possible to identify and validate biomarkers of interest for predicting the progression of prostate cancer and demonstrating the interest of combining these biomarkers in order to achieve better stratification of patients with prostate cancer. In the context of clinical utility, these results need to be validated on an independent and multicenter cohort in order to confirm these findings. This would eventually provide clinicians with a greater number of tools at their disposal to correctly anticipate patient trajectories and possibly identify new therapeutic targets for the control of the disease.
|
Page generated in 0.0271 seconds