RESUMEN
Emerging evidence suggests an important role for SIRT1, a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase in cancer development, progression and therapeutic resistance; making it a viable therapeutic target. Here, we examined the impact of resveratrol-mediated pharmacological activation of SIRT1 on the progression of HGPIN lesions (using the Pten-/- mouse model) and on prostate tumor development (using an orthotopic model of prostate cancer cells stably silenced for SIRT1). We show that precise SIRT1 modulation could benefit both cancer prevention and treatment. Positive effect of SIRT1 activation can prevent Pten deletion-driven development of HGPIN lesions in mice if resveratrol is administered early (pre-cancer stage) with little to no benefit after the establishment of HGPIN lesions or tumor cell implantation. Mechanistically, our results show that under androgen deprivation conditions, SIRT1 inhibition induces senescence as evidenced by decreased gene signature associated with negative regulators of senescence and increased senescence-associated ß-galactosidase activity. Furthermore, pharmacological inhibition of SIRT1 potentiated growth inhibitory effects of clinical androgen receptor blockade agents and radiation. Taken together, our findings provide an explanation for the discrepancy regarding the role of SIRT1 in prostate tumorigenesis. Our results reveal that the bifurcated roles for SIRT1 may occur in stage and context-dependent fashion by functioning in an antitumor role in prevention of early-stage prostate lesion development while promoting tumor development and disease progression post-lesion development. Clinically, these data highlight the importance of precise SIRT1 modulation to provide benefits for cancer prevention and treatment including sensitization to conventional therapeutic approaches.
Asunto(s)
Neoplasia Intraepitelial Prostática , Neoplasias de la Próstata , Antagonistas de Andrógenos/farmacología , Animales , Senescencia Celular , Humanos , Masculino , Ratones , Próstata/patología , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/prevención & control , Resveratrol/farmacología , Sirtuina 1/genéticaRESUMEN
2-Methoxyestradiol (2-ME2) possesses anti-tumorigenic activities in multiple tumor models with acceptable tolerability profile in humans. Incomplete understanding of the mechanism has hindered its development as an anti-tumorigenic compound. We have identified for the first-time macrophage stimulatory protein 1 receptor (MST1R) as a potential target of 2-ME2 in prostate cancer cells. Human tissue validation studies show that MST1R (a.k.a RON) protein levels are significantly elevated in prostate cancer tissues compared to adjacent normal/benign glands. Serum levels of macrophage stimulatory protein (MSP), a ligand for RON, is not only associated with the risk of disease recurrence, but also significantly elevated in samples from African American patients. 2-ME2 treatment inhibited mechanical properties such as adhesion and elasticity that are associated with epithelial mesenchymal transition by downregulating mRNA expression and protein levels of MST1R in prostate cancer cell lines. Intervention with 2-ME2 significantly reduced tumor burden in mice. Notably, global metabolomic profiling studies identified significantly higher circulating levels of bile acids in castrated animals that were decreased with 2-ME2 intervention. In summary, findings presented in this manuscript identified MSP as a potential marker for predicting biochemical recurrence and suggest repurposing 2-ME2 to target RON signaling may be a potential therapeutic modality for prostate cancer.
Asunto(s)
2-Metoxiestradiol/farmacología , Reposicionamiento de Medicamentos , Proteínas de Neoplasias , Neoplasias de la Próstata , Proteínas Tirosina Quinasas Receptoras , Animales , Humanos , Masculino , Ratones , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/metabolismo , Células PC-3 , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/patología , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Proteínas Tirosina Quinasas Receptoras/metabolismoRESUMEN
In this study we have identified POLθ-S6K-p62 as a novel druggable regulator of radiation response in prostate cancer. Despite significant advances in delivery, radiotherapy continues to negatively affect treatment outcomes and quality of life due to resistance and late toxic effects to the surrounding normal tissues such as bladder and rectum. It is essential to develop new and effective strategies to achieve better control of tumor. We found that ribosomal protein S6K (RPS6KB1) is elevated in human prostate tumors, and contributes to resistance to radiation. As a downstream effector of mTOR signaling, S6K is known to be involved in growth regulation. However, the impact of S6K signaling on radiation response has not been fully explored. Here we show that loss of S6K led to formation of smaller tumors with less metastatic ability in mice. Mechanistically we found that S6K depletion reduced NFκB and SQSTM1 (p62) reporter activity and DNA polymerase θ (POLθ) that is involved in alternate end-joining repair. We further show that the natural compound berberine interacts with S6K in a in a hitherto unreported novel mode and that pharmacological inhibition of S6K with berberine reduces Polθ and downregulates p62 transcriptional activity via NFκB. Loss of S6K or pre-treatment with berberine improved response to radiation in prostate cancer cells and prevented radiation-mediated resurgence of PSA in animals implanted with prostate cancer cells. Notably, silencing POLQ in S6K overexpressing cells enhanced response to radiation suggesting S6K sensitizes prostate cancer cells to radiation via POLQ. Additionally, inhibition of autophagy with CQ potentiated growth inhibition induced by berberine plus radiation. These observations suggest that pharmacological inhibition of S6K with berberine not only downregulates NFκB/p62 signaling to disrupt autophagic flux but also decreases Polθ. Therefore, combination treatment with radiation and berberine inhibits autophagy and alternate end-joining DNA repair, two processes associated with radioresistance leading to increased radiation sensitivity.
Asunto(s)
FN-kappa B , Neoplasias de la Próstata , Tolerancia a Radiación , Proteína Sequestosoma-1 , Transducción de Señal , Masculino , Animales , Humanos , Neoplasias de la Próstata/radioterapia , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/tratamiento farmacológico , Proteína Sequestosoma-1/metabolismo , Proteína Sequestosoma-1/genética , FN-kappa B/metabolismo , FN-kappa B/genética , Transducción de Señal/efectos de los fármacos , Ratones , Tolerancia a Radiación/efectos de los fármacos , Línea Celular Tumoral , ADN Polimerasa Dirigida por ADN/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Proteínas Quinasas S6 Ribosómicas 70-kDa/genéticaRESUMEN
The purpose of this study was to examine the effects of exercise in modulating biomarkers of sarcopenia in a treatment naïve transgenic adenocardinoma of the mouse prostate (TRAMP) model. Thirty TRAMP mice were randomized to either exercise (voluntary wheel running) or no-treatment control group for a period of 20 weeks. During necropsy, gastrocnemius muscles and prostate tumors were harvested and weighed. Gastrocnemius concentrations of myostatin, insulin-like growth factor (IGF)-1 and tumor necrosis factor (TNF)-α were quantified. Exercise mice had greater muscle mass than controls (p=0.04). Myostatin was significantly lower in the exercise group compared to controls (p=0.01). Exercise mice maintained forelimb grip force while control mice had a significaint decrease (p=0.01). No significant difference was observed in pre-post all limb grip strength. Further, forelimb and all limb grip strength was negatively associated with tumor mass (p<0.01).
RESUMEN
The purpose of this investigation was to compare the antitumorigenic effects of the natural product Nexrutine to voluntary wheel running (VWR) in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Forty-five, 10-week old TRAMP mice were randomized to either receive free access to the running wheel, Nexrutine pelleted into chow at 600 mg/kg or no treatment control. Mice were serially sacrificed at weeks 4, 8,12 and 20 weeks. Palpable tumors, body weight, food consumption and running wheel activity were monitored weekly. At necropsy, tumors and serum were harvested and stored for analysis. Serum was used to quantify circulating cytokines in 4 and 20 week time points. Nexrutine supplementation led to a 66% protection against high grade tumors. Exercise resulted in a 60% protection against high grade tumors. Both interventions reduced concentrations of IL-1α. Exercise also significantly lowered concentrations of eotaxin, IL-5, IL-12(p40) and VEGF. While there were no significant differences at baseline, exercise mice had significantly lower IL-5 and VEGF compared to control at the 20 week time point. Nexrutine also significantly reduced circulating IL-9 concentrations. No significant differences were observed when compared to the control group. Immunohistochemistry of tumor sections showed significantly lower expression of pAkt in Nexrutine fed mice with no visible differences for NFκB. In conclusion, both Nexrutine and exercise suppressed tumor growth. Though similar outcomes were seen in this comparative effectiveness study, the mechanisms by which exercise and Nexrutine exert this benefit may focus on different pathways.
Asunto(s)
Condicionamiento Físico Animal , Extractos Vegetales/farmacología , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/prevención & control , Animales , Proliferación Celular/efectos de los fármacos , Citocinas/metabolismo , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Masculino , Ratones , Ratones Transgénicos , Clasificación del Tumor , Fosfoproteínas/metabolismo , Neoplasias de la Próstata/fisiopatología , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
Muscle loss is a debilitating side effect to prostate cancer (PCa) experienced by nearly 60% of men. The purpose of this study was to test the hypothesis that Nexrutine® , a bark extract from the Phellodendrum amurense, can protect against prostate cancer induced muscle loss in a similar manner as exercise, using the transgenic adenocarcinoma of mouse prostate (TRAMP) model. Forty-five, 8- to 10-week old TRAMP mice were randomized to either control, Nexrutine® (600 mg/kg pelleted in chow) or exercise (voluntary wheel running). Mice were serially sacrificed at weeks 4, 8, 12, and 20, at which time either the left or right gastrocnemius muscle was harvested, weighted, and frozen. Proteolysis inducing factor (PIF), ubiquitin, and NF-κB concentrations were quantified using ELISA kits. Nexrutine® and exercise were equally able to protect TRAMP mice against PCa-induced muscle loss (P = 0.04). Both interventions decreased intramuscular PIF concentrations at 20 weeks compared to control (P < 0.05). A treatment effect was also observed when all time points were combined with exercise significantly lowering PIF concentrations (P < 0.01). Exercise significantly lowered intramuscular ubiquitin concentrations in weeks 4, 8, and 20 compared to control mice (P < 0.001). A treatment effect was also observed with exercise significantly lowering ubiquitin compared to control mice (P < 0.001). No significant changes were observed for NF-κB. The results of this investigation demonstrate that PCa-induced muscle loss can be attenuated with the herbal supplement Nexrutine® . This investigation provides preliminary evidence to support continued research into Nexrutine® as a potential exercise analog in protecting against muscle loss.
Asunto(s)
Adenocarcinoma/complicaciones , Músculo Esquelético/efectos de los fármacos , Extractos Vegetales/farmacología , Neoplasias de la Próstata/complicaciones , Animales , Atrofia/etiología , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Condicionamiento Físico Animal , Distribución AleatoriaRESUMEN
Radiation therapy (XRT) is a standard treatment for prostate cancer (PCa). Although dose escalation increases local control, toxicity hampers further escalation. Broader improvement will be possible by the addition of adjuvant therapies, which can synergize with radiation and thus improve efficacy. We have identified a natural compound (Nexrutine, Nx) that inhibits the survival and growth of PCa cells in combination with radiation. Combination studies demonstrated strong interaction between Nx and radiation both in vitro in multiple PCa cell lines and in the Transgenic adenocarcinoma of mouse prostate (TRAMP) model. Nx potentiated growth inhibitory effects of IR by down regulating ribosomal protein S6K (RPS6KB1), CyclinD1, Chk1 and HIF-1 α and prolonging G2/M checkpoint block. RPS6KB1 is upregulated in prostate cancers and its expression is correlated with tumor grade. Knockdown of RPS6KB1 in PCa cells increased their sensitivity toward radiation-induced survival inhibition. Overall, we provide scientific evidence (i) in support of Nx as an adjuvant in PCa patients receiving XRT (ii) suggesting that RPS6KB1 is an important player in Nx-mediated combinatorial benefits and emphasizes that RPS6KB1 is a novel target for PCa treatment. These data underscore the need to test the agent in additional preclinical models to validate these observations.
Asunto(s)
Antineoplásicos/farmacología , Extractos Vegetales/farmacología , Neoplasias de la Próstata/radioterapia , Proteínas Quinasas S6 Ribosómicas 70-kDa/antagonistas & inhibidores , Proteínas Quinasas S6 Ribosómicas 70-kDa/genética , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Proliferación Celular/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/biosíntesis , Ciclina D1/biosíntesis , Puntos de Control de la Fase G2 del Ciclo Celular/efectos de los fármacos , Técnicas de Silenciamiento del Gen , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/biosíntesis , Masculino , Ratones , Células PC-3 , Proteínas Quinasas S6 Ribosómicas 70-kDa/biosíntesisRESUMEN
PURPOSE: Near equal rates of incidence and mortality emphasize the need for novel targeted approaches for better management of patients with pancreatic cancer. Inflammatory molecules NF-κB and STAT3 are overexpressed in pancreatic tumors. Inhibition of one protein allows cancer cells to survive using the other. The goal of this study is to determine whether targeting STAT3/NF-κB crosstalk with a natural product Nexrutine can inhibit inflammatory signaling in pancreatic cancer. EXPERIMENTAL DESIGN: HPNE, HPNE-Ras, BxPC3, Capan-2, MIA PaCa-2, and AsPC-1 cells were tested for growth, apoptosis, cyclooxygenase-2 (COX-2), NF-κB, and STAT3 level in response to Nexrutine treatment. Transient expression, gel shift, chromatin immunoprecipitation assay was used to examine transcriptional regulation of COX-2. STAT3 knockdown was used to decipher STAT3/NF-κB crosstalk. Histopathologic and immunoblotting evaluation was performed on BK5-COX-2 transgenic mice treated with Nexrutine. In vivo expression of prostaglandin receptor E-prostanoid 4 (EP4) was analyzed in a retrospective cohort of pancreatic tumors using a tissue microarray. RESULTS: Nexrutine treatment inhibited growth of pancreatic cancer cells through induction of apoptosis. Reduced levels and activity of STAT3, NF-κB, and their crosstalk led to transcriptional suppression of COX-2 and subsequent decreased levels of prostaglandin E2 (PGE2) and PGF2. STAT3 knockdown studies suggest STAT3 as negative regulator of NF-κB activation. Nexrutine intervention reduced the levels of NF-κB, STAT3, and fibrosis in vivo. Expression of prostaglandin receptor EP4 that is known to play a role in fibrosis was significantly elevated in human pancreatic tumors. CONCLUSIONS: Dual inhibition of STAT3-NF-κB by Nexrutine may overcome problems associated with inhibition of either pathway.
Asunto(s)
Ciclooxigenasa 2/metabolismo , FN-kappa B/metabolismo , Neoplasias Pancreáticas/metabolismo , Extractos Vegetales/farmacología , Subtipo EP4 de Receptores de Prostaglandina E/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Antineoplásicos Fitogénicos/administración & dosificación , Antineoplásicos Fitogénicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Fibrosis , Expresión Génica , Humanos , Inmunohistoquímica , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Extractos Vegetales/administración & dosificación , Unión Proteica , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
SIRT1 (mammalian ortholog of the yeast silent information regulator 2) is a NAD-dependent histone deacetylase belonging to the multigene family of sirtuins. Anecdotal and epidemiologic observations provide evidence for beneficial effects of the calorie restriction mimetic resveratrol (RES), a SIRT1 activator in preventing cardiovascular diseases and cancer. Although SIRT1 possesses both tumorigenic and antitumorigenic potential, the molecular mechanisms underlying SIRT1-mediated tumor progression or inhibition are poorly understood. In this study, we investigated the role of SIRT1 in multiple human prostate cancer cell lines and prostate-specific PTEN knockout mouse model using resveratrol. Androgen-independent prostate cancer cell lines (C42B, PC3, and DU145) express higher levels of SIRT1 than androgen-responsive (LNCaP) and nontumorigenic prostate cells (RWPE-1). Resveratrol enhanced this expression without any significant effect on SIRT1 enzymatic activity. Inhibition of SIRT1 expression using shRNA enhanced cell proliferation and inhibited autophagy by repressing phosphorylation of S6K and 4E-BP1. These biologic correlates were reversed in the presence of resveratrol. Analysis of prostates from dietary intervention with resveratrol showed a significant reduction in prostate weight and reduction in the incidence of high-grade prostatic intraepithelial neoplastic (HGPIN) lesions by approximately 54% with no significant change in body weight. Consistent with the in vitro findings, resveratrol intervention in the PTEN knockout mouse model was associated with reduction in the prostatic levels of mTOR complex 1 (mTORC1) activity and increased expression of SIRT1. These data suggest that SIRT1/S6K-mediated inhibition of autophagy drives prostate tumorigenesis. Therefore, modulation of SIRT1/S6K signaling represents an effective strategy for prostate cancer prevention.
Asunto(s)
Neoplasia Intraepitelial Prostática/tratamiento farmacológico , Neoplasias de la Próstata/tratamiento farmacológico , Proteínas Quinasas S6 Ribosómicas/metabolismo , Sirtuina 1/metabolismo , Estilbenos/administración & dosificación , Alimentación Animal , Animales , Línea Celular Tumoral , Supervivencia Celular , Dieta , Humanos , Inmunohistoquímica/métodos , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Ratones Noqueados , Complejos Multiproteicos/metabolismo , Mutación , Fosforilación , Neoplasia Intraepitelial Prostática/prevención & control , Neoplasias de la Próstata/prevención & control , ARN Interferente Pequeño/metabolismo , Resveratrol , Transducción de Señal , Estilbenos/farmacología , Serina-Treonina Quinasas TOR/metabolismo , Sales de Tetrazolio/farmacología , Tiazoles/farmacología , Factores de TiempoRESUMEN
Prostate cancer is the second leading cause of cancer-related deaths in men in Western society. Epidemiological studies suggest that a reduced risk of cancer is associated with the consumption of a phytochemical-rich diet that includes fruits and vegetables. Strategies to delay clinically significant prostate cancer will have a tremendous impact in reducing the overall incidence of prostate cancer as well as improving quality of life for elderly men. Furthermore, the long latency involved in the development of clinically significant prostate cancer provides a plethora of opportunities for its management, especially using prevention approaches. Previous studies from our laboratory show that Nexrutine (bark extract from Phellodendron amurense) prevents prostate tumor development when given prior to the development of high-grade prostatic intraepithelial neoplasia in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. In this study, we investigated the effect on the progression of established tumors in the TRAMP model by administering Nexrutine to 28-week-old TRAMP mice. Efficacy of Nexrutine was determined by histopathological evaluation of the prostate. Our data indicate that Nexrutine inhibited progression of prostate tumors that was correlated with tissue levels of transcription factors nuclear factor kappa B, cyclic-AMP response element-binding protein and phosphorylated CREB. Moreover, Nexrutine intervention resulted in a significant increase in the bone mineral density of the left femur diaphysis (p=0.009) and prevented the development of metastatic lesions. Nexrutine treatment also significantly (p=0.005) inhibited invasion of androgen-independent prostate cancer cells.