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- Glutaminolysis is a metabolic route essential for survival and growth of prostate cancer cells and a target of 5 alpha-dihydrotestosterone regulationPublication . Cardoso, Henrique J.; Figueira, Marilia, I; Vaz, Catia V.; Carvalho, Tiago M. A.; Bras, Luis A.; Madureira, Patricia; Oliveira, Paulo J.; Sardao, Vilma A.; Socorro, SilviaPurpose Resistance to androgen-deprivation therapies and progression to so-called castrate-resistant prostate cancer (CRPC) remain challenges in prostate cancer (PCa) management and treatment. Among other alterations, CRPC has been associated with metabolic reprogramming driven by androgens. Here, we investigated the role of androgens in regulating glutaminolysis in PCa cells and determined the relevance of this metabolic route in controlling the survival and growth of androgen-sensitive (LNCaP) and CRPC (DU145 and PC3) cells. Methods PCa cells (LNCaP, DU145 and PC3) and 3-month old rats were treated with 5 alpha-dihydrotestosterone (DHT). Alternatively, LNCaP cells were exposed to the glutaminase inhibitor BPTES, alone or in combination with the anti-androgen bicalutamide. Biochemical, Western blot and extracellular flux assays were used to evaluate the viability, proliferation, migration and metabolism of PCa cells in response to DHT treatment or glutaminase inhibition. Results We found that DHT up-regulated the expression of the glutamine transporter ASCT2 and glutaminase, both in vitro in LNCaP cells and in vivo in rat prostate cells. BPTES diminished the viability and migration of PCa cells, while increasing caspase-3 activity. CRPC cells were found to be more dependent on glutamine and more sensitive to glutaminase inhibition. BPTES and bicalutamide co-treatment had an additive effect on suppressing LNCaP cell viability. Finally, we found that inhibition of glutaminolysis differentially affected glycolysis and lipid metabolism in both androgen-sensitive and CRPC cells. Conclusion Our data reveal glutaminolysis as a central metabolic route controlling PCa cell fate and highlight the relevance of targeting glutaminase for CRPC treatment.
- TRIB2 confers resistance to anti-cancer therapy by activating the serine/threonine protein kinase AKTPublication . Hill, Richard; Madureira, Patricia; Ferreira, Bibiana; Baptista, Inês; Machado, S.; Colaco, Laura; dos Santos, Marta; Liu, Ningshu; Dopazo, Ana; Ugurel, Selma; Adrienn, Angyal; Kiss-Toth, Endre; Isbilen, Murat; Gure, Ali O.; Link, WolfgangIntrinsic and acquired resistance to chemotherapy is the fundamental reason for treatment failure for many cancer patients. The identification of molecular mechanisms involved in drug resistance or sensitization is imperative. Here we report that tribbles homologue 2 (TRIB2) ablates forkhead box O activation and disrupts the p53/MDM2 regulatory axis, conferring resistance to various chemotherapeutics. TRIB2 suppression is exerted via direct interaction with AKT a key signalling protein in cell proliferation, survival and metabolism pathways. Ectopic or intrinsic high expression of TRIB2 induces drug resistance by promoting phospho-AKT (at Ser473) via its COP1 domain. TRIB2 expression is significantly increased in tumour tissues from patients correlating with an increased phosphorylation of AKT, FOXO3a, MDM2 and an impaired therapeutic response. This culminates in an extremely poor clinical outcome. Our study reveals a novel regulatory mechanism underlying drug resistance and suggests that TRIB2 functions as a regulatory component of the PI3K network, activating AKT in cancer cells.
- Mechanism of plasmin generation by S100A10Publication . Miller, Victoria A.; Madureira, Patricia; Kamaludin, Ain Adilliah; Komar, Jeffrey; Sharma, Vandna; Sahni, Girish; Thewell, Craig; Longstaff, Colin; Waisman, David M.Plasminogen (Pg) is cleaved to form plasmin by the action of specific plasminogen activators such as the tissue plasminogen activator (tPA). Although the interaction of tPA and Pg with the surface of the fibrin clot has been well characterised, their interaction with cell surface Pg receptors is poorly understood. S100A10 is a cell surface Pg receptor that plays a key role in cellular plasmin generation. In the present report, we have utilised domain-switched/deleted variants of tPA, truncated plasminogen variants and S100A10 site-directed mutant proteins to define the regions responsible for S100A10-dependent plasmin generation. In contrast to the established role of the finger domain of tPA in fibrin-stimulated plasmin generation, we show that the kringle-2 domain of tPA plays a key role in S100A10-dependent plasmin generation. The kringle-1 domain of plasminogen, indispensable for fibrin-binding, is also critical for S100A10-dependent plasmin generation. S100A10 retains activity after substitution or deletion of the carboxyl-terminal lysine suggesting that internal lysine residues contribute to its plasmin generating activity. These studies define a new paradigm for plasminogen activation by the plasminogen receptor, S100A10.
- The biochemistry and regulation of S100A10: a multifunctional plasminogen receptor involved in oncogenesisPublication . Madureira, Patricia; O'Connell, Paul A.; Surette, Alexi P.; Miller, Victoria A.; Waisman, David M.The plasminogen receptors mediate the production and localization to the cell surface of the broad spectrum proteinase, plasmin. S100A10 is a key regulator of cellular plasmin production and may account for as much as 50% of cellular plasmin generation. In parallel to plasminogen, the plasminogen-binding site on S100A10 is highly conserved from mammals to fish. S100A10 is constitutively expressed in many cells and is also induced by many diverse factors and physiological stimuli including dexamethasone, epidermal growth factor, transforming growth factor-alpha, interferon-gamma, nerve growth factor, keratinocyte growth factor, retinoic acid, and thrombin. Therefore, S100A10 is utilized by cells to regulate plasmin proteolytic activity in response to a wide diversity of physiological stimuli. The expression of the oncogenes, PML-RAR alpha and KRas, also stimulates the levels of S100A10, suggesting a role for S100A10 in pathophysiological processes such as in the oncogenic-mediated increases in plasmin production. The S100A10-null mouse model system has established the critical role that S100A10 plays as a regulator of fibrinolysis and oncogenesis. S100A10 plays two major roles in oncogenesis, first as a regulator of cancer cell invasion and metastasis and secondly as a regulator of the recruitment of tumor-associated cells, such as macrophages, to the tumor site.
- Genotoxic agents promote the nuclear accumulation of annexin A2: role of annexin A2 in mitigating DNA damagePublication . Madureira, Patricia A.; Hill, Richard; Lee, Patrick W. K.; Waisman, David M.Annexin A2 is an abundant cellular protein that is mainly localized in the cytoplasm and plasma membrane, however a small population has been found in the nucleus, suggesting a nuclear function for the protein. Annexin A2 possesses a nuclear export sequence (NES) and inhibition of the NES is sufficient to cause nuclear accumulation. Here we show that annexin A2 accumulates in the nucleus in response to genotoxic agents including gamma-radiation, UV radiation, etoposide and chromium VI and that this event is mediated by the nuclear export sequence of annexin A2. Nuclear accumulation of annexin A2 is blocked by the antioxidant agent N-acetyl cysteine (NAC) and stimulated by hydrogen peroxide (H2O2), suggesting that this is a reactive oxygen species dependent event. In response to genotoxic agents, cells depleted of annexin A2 show enhanced phospho-histone H2AX and p53 levels, increased numbers of p53-binding protein 1 nuclear foci and increased levels of nuclear 8-oxo-2'-deoxyguanine, suggesting that annexin A2 plays a role in protecting DNA from damage. This is the first report showing the nuclear translocation of annexin A2 in response to genotoxic agents and its role in mitigating DNA damage.
- The role of hypoxia in glioblastoma invasionPublication . Monteiro, Ana; Hill, Richard; Pilkington, Geoffrey; A Madureira, PatriciaGlioblastoma multiforme (GBM), a grade IV astrocytoma, is the most common and deadly type of primary malignant brain tumor, with a patient's median survival rate ranging from 15 to 17 months. The current treatment for GBM involves tumor resection surgery based on MRI image analysis, followed by radiotherapy and treatment with temozolomide. However, the gradual development of tumor resistance to temozolomide is frequent in GBM patients leading to subsequent tumor regrowth/relapse. For this reason, the development of more effective therapeutic approaches for GBM is of critical importance. Low tumor oxygenation, also known as hypoxia, constitutes a major concern for GBM patients, since it promotes cancer cell spreading (invasion) into the healthy brain tissue in order to evade this adverse microenvironment. Tumor invasion not only constitutes a major obstacle to surgery, radiotherapy, and chemotherapy, but it is also the main cause of death in GBM patients. Understanding how hypoxia triggers the GBM cells to become invasive is paramount to developing novel and more effective therapies against this devastating disease. In this review, we will present a comprehensive examination of the available literature focused on investigating how GBM hypoxia triggers an invasive cancer cell phenotype and the role of these invasive proteins in GBM progression.
- Androgens and low density lipoprotein-cholesterol interplay in modulating prostate cancer cell fate and metabolismPublication . Cardoso, Henrique J.; Figueira, Marília I.; Carvalho, Tiago M.A.; Serra, Catarina D.M.; Vaz, Cátia V.; Madureira, Patricia; Socorro, SílviaBackground: Androgens, the known drivers of prostate cancer (PCa), have been indicated as important metabolic regulators with a relevant role in stimulating lipid metabolism. Also, the relationship between obesity and the aggressiveness of PCa has been established. However, it is unknown if the androgenic hormonal environment may alter the response of PCa cells to lipid availability. Purpose: The present study evaluated the effect of 5 alpha-dihydrotestosterone (DHT) in regulating lipid metabolism, and the interplay between this hormone and low-density lipoprotein (LDL)-cholesterol in modulating PCa cells fate.Methods: Non-neoplastic and neoplastic PCa cells were treated with 10 nM DHT, and the expression of fatty acids transporter, fatty acid synthase (FASN), and carnitine palmitoyltransferase 1A (CPT1A) evaluated. PCa cells were also exposed to LDL (100 mu g/ml) in the presence or absence of DHT.Results: Treatment with DHT upregulated the expression of FASN and CPT1A in androgen-sensitive PCa cells. In contrast, LDL supplementation suppressed FASN expression regardless of the presence of DHT, whereas aug-menting CPT1A levels. Our results also showed that LDL-cholesterol increased PCa cells viability, proliferation, and migration dependently on the presence of DHT. Moreover, LDL and DHT synergistically enhanced the accumulation of lipid droplets in PCa cells.Conclusions: The obtained results show that androgens deregulate lipid metabolism and enhance the effects of LDL increasing PCa cells viability, proliferation and migration. The present findings support clinical data linking obesity with PCa and first implicate androgens in this relationship. Also, they sustain the application of phar-macological approaches targeting cholesterol availability and androgens signaling simultaneously.
- Corrigendum to IP1867B suppresses the insulin-like growth factor 1 receptor (IGF1R) ablating epidermal growth factor receptor inhibitor resistance in adult high grade gliomas (vol 458C, pg 29, 2019)Publication . Mihajluk, K.; Simms, C.; Reay, M.; A Madureira, Patricia; Howarth, A.; Murray, P.; Nasser, S.; Duckworth, C. A.; Pritchard, D. M.; Pilkington, G. J.; Hill, R.
- Retraction notice to " IP1867B suppresses the Insulin-like Growth Factor 1 Receptor (IGF1R) ablating epidermal growth factor receptor inhibitor resistance in adult high grade gliomas” [Canc. Lett., 458 (2019) pages 29–38]Publication . Mihajluk, K.; Simms, C.; Reay, M.; A Madureira, Patricia; Howarth, A.; Murray, P.; Nasser, S.; Duckworth, C.A.; Pritchard, D.M.; Pilkington, G.J.; Hill, R.This article has been retracted at the request of the Editor-in-Chief due to concerns regarding the legitimacy of images and data presented in the paper. Though a corrigendum (Can. Lett. Vol. 469, 2020, pages 524–535) was previously published to address some of these concerns, this corrigendum has also been found to contain errors and therefore cannot stand. Specific concerns are listed below.
- Retraction note: TRIB2 confers resistance to anti-cancer therapy by activating the serine/threonine protein kinase AKTPublication . Hill, Richard; Madureira, Patricia; Ferreira, Bibiana; Baptista, Ines; Machado, Susana; Colaҫo, Laura; dos Santos, Marta; Liu, Ningshu; Dopazo, Ana; Ugurel, Selma; Adrienn, Angyal; Kiss-Toth, Endre; Isbilen, Murat; Gure, Ali O.; Link, WolfgangThe authors have retracted this article as it has come to their attention that several images were inappropriately processed and duplicated in multiple figures. In particular, the data were duplicated, and in some cases inverted, across several panels in Figures 2c, 2b, 3d and Supplementary Figure 5. Erroneous data were also included in Figure 2e, Supplementary Figure 1 and Supplementary Figure 8. We apologize to the scientific community for any confusion this article may have caused. Richard Hill, Patricia Madureira, Bibiana I. Ferreira, Susana Machado, Ana Dopazo, Selma Ugurel, Endre Kiss-Toth, Murat isbilen and Wolfgang Link agree with this retraction. Inês Baptista, Laura Colaço, Marta dos Santos, Ningshu Liu, Angyal Adrienn and Ali O. Gure have not responded to correspondence from the Publisher about this retraction.