Combination of Sulindac and Eflornithine Delays the Need for Lower Gastrointestinal Surgery in Patients With Familial Adenomatous Polyposis: Post Hoc Analysis of a Randomized Clinical Trial.

BACKGROUND: Colectomy and proctocolectomy are the initial standard of care for patients with familial adenomatous polyposis. Pharmacotherapy to prevent the progression of polyposis and surgeries in the lower GI tract would be beneficial to patients with this disease. OBJECTIVE: This analysis aimed to evaluate the impact of eflornithine-sulindac combination versus monotherapy in delaying time to disease progression in the lower GI tract of patients with familial adenomatous polyposis. DESIGN: This is a post hoc analysis of a randomized phase 3 trial. SETTING: This study was conducted in 21 hospitals in 7 countries treating patients with familial adenomatous polyposis. PATIENTS: Adults with familial adenomatous polyposis were randomly assigned 1:1:1 into 3 arms. INTERVENTIONS: Patients received either eflornithine (750 mg), sulindac (150 mg), or both once daily for up to 48 months. MAIN OUTCOME MEASURES: Efficacy was evaluated as the time from randomization to predefined primary disease progression end points. RESULTS: A total of 158 patients were included in the study. Disease progression was observed in 2 of 54 (3.7%), 9 of 53 (17.0%), and 10 of 51 (19.6%) patients with at least partial lower GI tract in the combination, sulindac, and eflornithine arms, corresponding to risk reductions of 80% (p = 0.02) and 83% (p = 0.01) between combination and sulindac or eflornithine. When endoscopic excision of adenomas ≥10 mm in size was censored, the need for major surgery was observed in 0 of 54, 7 of 53 (13.2%), and 8 of 51 (15.7%) patients in the combination, sulindac, and eflornithine arms, corresponding to risk reductions approaching 100% between combination and sulindac (p = 0.005) or combination and eflornithine (p = 0.003). LIMITATIONS: This was a post hoc analysis, the sample size was small, and there were fewer than expected events. CONCLUSIONS: Eflornithine-sulindac combination therapy was superior to either drug alone in delaying or preventing the need for lower GI tract surgery in patients with familial adenomatous polyposis. See Video Abstract at http://links.lww.com/DCR/B658. REGISTRATION: ClinicalTrials.gov, NCT01483144; EU Clinical Trials Register, EudraCT 2012-000427-41. LA COMBINACIN DE SULINDAC Y EFLORNITINA RETRASA LA NECESIDAD DE CIRUGA DEL TUBO DIGESTIVO BAJO EN PACIENTES CON PAF ANLISIS POSTHOC DE UN ENSAYO CLNICO ALEATORIZADO: ANTECEDENTES:La colectomía y la proctocolectomía son el estándar inicial de atención para los pacientes con poliposis adenomatosa familiar. La farmacoterapia para prevenir la progresión de la poliposis y las cirugías en el tracto gastrointestinal inferior sería beneficiosa para los pacientes con esta enfermedad.OBJETIVO:Este análisis tuvo como objetivo evaluar el impacto de la combinación de eflornitina-sulindac versus la monoterapia en el retraso del tiempo hasta la progresión de la enfermedad en el tracto gastrointestinal inferior de pacientes con poliposis adenomatosa familiar.DISEÑO:Este es un análisis posthoc de un ensayo de fase 3 aleatorizado.ENTORNO CLINICO:Veintiún hospitales en 7 países que tratan a pacientes con poliposis adenomatosa familiar.PACIENTES:Adultos con poliposis adenomatosa familiar fueron aleatorizados 1: 1: 1 en 3 brazos.INTERVENCIONES:Los pacientes recibieron eflornitina (750 mg), sulindac (150 mg) o ambos una vez al día durante un máximo de 48 meses.PRINCIPALES MEDIDAS DE VALORACION:La eficacia se evaluó como el tiempo desde la aleatorización hasta los criterios de valoración primarios predefinidos de progresión de la enfermedad.RESULTADOS:Los resultados se informan para la población de estudio excluyendo a los pacientes que se habían sometido a ileostomías permanentes (n = 158). Se observó progresión de la enfermedad en 2/54 (3,7%), 9/53 (17,0%) y 10/51 (19,6%) pacientes con al menos tracto gastrointestinal inferior parcial en los brazos de combinación, sulindac y eflornitina, respectivamente, correspondientes al riesgo de reducciones del 80% (p = 0,02) y del 83% (p = 0,01) entre la combinación y el sulindaco o la eflornitina, respectivamente. Cuando se censuró la escisión endoscópica de adenomas ≥10 mm de tamaño, se observó la necesidad de cirugía mayor en 0/54, 7/53 (13,2%) y 8/51 (15,7%) pacientes en la combinación, sulindac y eflornitina, respectivamente, correspondientes a reducciones de riesgo cercanas al 100% entre combinación y sulindac (p = 0,005) o combinación y eflornitina (p = 0,003).LIMITACIONES:Este fue un análisis posthoc, el tamaño de la muestra fue pequeño y hubo menos eventos de los esperados.CONCLUSIONES:La terapia de combinación de eflornitina-sulindac fue superior a cualquier fármaco solo para retrasar o prevenir la necesidad de cirugía del tracto gastrointestinal inferior en pacientes con poliposis adenomatosa familiar. Consulte Video Resumen en http://links.lww.com/DCR/B658.

A small-molecule activator of the unfolded protein response eradicates human breast tumors in mice.

Metastatic estrogen receptor α (ERα)-positive breast cancer is presently incurable. Seeking to target these drug-resistant cancers, we report the discovery of a compound, called ErSO, that activates the anticipatory unfolded protein response (a-UPR) and induces rapid and selective necrosis of ERα-positive breast cancer cell lines in vitro. We then tested ErSO in vivo in several preclinical orthotopic and metastasis mouse models carrying different xenografts of human breast cancer lines or patient-derived breast tumors. In multiple orthotopic models, ErSO treatment given either orally or intraperitoneally for 14 to 21 days induced tumor regression without recurrence. In a cell line tail vein metastasis model, ErSO was also effective at inducing regression of most lung, bone, and liver metastases. ErSO treatment induced almost complete regression of brain metastases in mice carrying intracranial human breast cancer cell line xenografts. Tumors that did not undergo complete regression and regrew remained sensitive to retreatment with ErSO. ErSO was well tolerated in mice, rats, and dogs at doses above those needed for therapeutic responses and had little or no effect on normal ERα-expressing murine tissues. ErSO mediated its anticancer effects through activation of the a-UPR, suggesting that activation of a tumor protective pathway could induce tumor regression.

Antibody-dependent cell-mediated cytotoxicity effector-enhanced EphA2 agonist monoclonal antibody demonstrates potent activity against human tumors.

EphA2 is a receptor tyrosine kinase that has been shown to be overexpressed in a variety of human tumor types. Previous studies demonstrated that agonist monoclonal antibodies targeting EphA2 induced the internalization and degradation of the receptor, thereby abolishing its oncogenic effects. In this study, the in vitro and in vivo antibody-dependent cell-mediated cytotoxicity (ADCC) activity of EphA2 effector-enhanced agonist monoclonal antibodies was evaluated. With tumor cell lines and healthy human peripheral blood monocytes, the EphA2 antibodies demonstrated approximately 80% tumor cell killing. In a dose-dependent manner, natural killer (NK) cells were required for the in vitro ADCC activity and became activated as demonstrated by the induction of cell surface expression of CD107a. To assess the role of NK cells on antitumor efficacy in vivo, the EphA2 antibodies were evaluated in xenograft models in severe compromised immunodeficient (SCID) mice (which have functional NK cells and monocytes) and SCID nonobese diabetic (NOD) mice (which largely lack functional NK cells and monocytes). Dosing of EphA2 antibody in the SCID murine tumor model resulted in a 6.2-fold reduction in tumor volume, whereas the SCID/nonobese diabetic model showed a 1.6-fold reduction over the isotype controls. Together, these results demonstrate that the anti-EphA2 monoclonal antibodies may function through at least two mechanisms of action: EphA2 receptor activation and ADCC-mediated activity. These novel EphA2 monoclonal antibodies provide additional means by which host effector mechanisms can be activated for selective destruction of EphA2-expressing tumor cells.

TGF-beta signaling and androgen receptor status determine apoptotic cross-talk in human prostate cancer cells.

BACKGROUND: A signaling interaction between transforming growth factor-beta (TGF-beta) and androgens promotes apoptosis in human prostate cancer cells LNCaP-TbetaRII (androgen-sensitive and TGF-beta responsive). This study investigated the contribution of androgen receptor (AR) in the combined effect of TGF-beta and dihydrotestosterone (DHT), on regulation of apoptosis and AR- and TGF-beta mediated transcriptional activity in human prostate cancer cells. METHODS: Transcriptional activation in response to TGF-beta (5 ng/ml) and DHT (1 nM) was evaluated using transient transfections and luciferase assays in human prostate cancer cells, LNCaP-TbetaRII and PC-3, overexpressing the wild type AR. The apoptotic response to DHT/TGFbeta treatment was correlated with AR cellular distribution and the AR interaction with TGF-beta intracellular effector Smad4. RESULTS: The results revealed that TGF-beta signaling induced AR-mediated transcriptional activation in two androgen-responsive promoters [probasin and prostate specific antigen (PSA)]. TGF-beta1 induced transcriptional activity enhanced by DHT in both cell lines (LNCaP-TbetaRII and PC-3-AR) via AR-Smad4 interaction. This interaction however does not exclusively drive TGF-beta mediated apoptosis as DHT failed to enhance such an effect in PC-3 AR (wt) cells. CONCLUSIONS: These results demonstrate that the AR status determines the sensitivity of prostate cancer cells to the apoptotic effects of TGF-beta1, thus providing a new insight into the mechanism via which TGF-beta cross-sections the AR axis toward the functional convergence of the two pathways in the development of androgen-independent prostate cancer. This study is potentially significant in defining the contribution of AR status to the emergence of androgen-independent prostate tumors.

Long-term suppression of experimental arthritis following intramuscular administration of a pseudotyped AAV2/1-TNFR:Fc Vector.

We previously reported that administration of an adeno-associated virus 2 (AAV2) vector encoding a rat tumor necrosis factor (TNF) receptor-immunoglobulin Fc (TNFR:Fc) fusion gene to rats with streptococcal cell wall-induced arthritis resulted in suppression of joint inflammation and cartilage and bone destruction, as well as expression of joint proinflammatory cytokines. In this study, we used an alternate rat model of arthritis to compare the serum levels and duration of TNFR:Fc protein expression following intramuscular administration of pseudotyped AAV-TNFR:Fc vectors based on serotypes 1, 2, and 5. All three pseudotyped AAV-TNFR:Fc vectors led to sustained expression of serum TNFR:Fc protein for at least one year. Serum TNFR:Fc protein levels in rats administered intramuscularly with AAV2/1-TNFR:Fc vector were up to 100- and 10-fold higher than in rats administered the AAV2-TNFR:Fc or AAV2/5-TNFR:Fc vectors, respectively. A single intramuscular administration of AAV2/1-TNFR:Fc vector at vector doses ranging from 10(10) to 10(12) DNase-resistant particles (DRP) per animal, resulted in complete and long-term suppression of recurrent joint inflammation for at least 150 days. Our results establish a proof of concept for administration of an AAV2/1-TNFR:Fc vector to the muscle to achieve long-term, sustained and therapeutically relevant levels of TNFR:Fc protein to treat chronic systemic inflammatory joint diseases.

Secretion of a TNFR:Fc fusion protein following pulmonary administration of pseudotyped adeno-associated virus vectors.

This study evaluated and compared delivery of the tumor necrosis factor alpha receptor (TNFR)-immunoglobulin G1 (IgG1) Fc fusion (TNFR:Fc) gene to the lung by single and repeat administrations of multiple pseudotyped adeno-associated virus (AAV) vectors as a means for achieving systemic distribution of the soluble TNFR:Fc protein. A single endotracheal administration of AAV[2/5]cytomegalovirus (CMV)-TNFR:Fc vector (containing the AAV2 inverted terminal repeats and AAV5 capsid) to the rat lung resulted in long-term, high levels of serum TNFR:Fc protein that gradually declined over a period of 8 months. Endotracheal delivery of AAV[2/1]CMV-TNFR:Fc resulted in serum TNFR:Fc protein levels that were detectable for at least 4 months but were 10-fold lower than that of the AAV[2/5] vector. In contrast, secretion of the TNFR:Fc protein following pulmonary delivery of AAV[2/2]CMV-TNFR:Fc vector was very inefficient, and the protein was detected in the blood only when an airway epithelial cell-specific promoter, CC10, was substituted for the CMV enhancer/promoter to control transgene expression. In the context of AAV[2/5], the CC10 promoter was as efficient as CMV enhancer/promoter in generating similar levels of systemic TNFR:Fc protein, suggesting that this protein is secreted primarily from the airway epithelium. In mice, comparable long-term secretion of TNFR:Fc protein was demonstrated after AAV[2/2] and AAV[2/5] delivery, although the kinetics of transduction appeared to be different. All pseudotyped AAV vectors elicited serum anti-AAV capsid-neutralizing antibody responses, but these did not prevent lung transduction and efficient secretion of TNFR:Fc protein to the circulation following readministration with AAV[2/5]. These results highlight the potential utility of AAV vectors containing serotype 5 capsid to deliver and redeliver genes of secreted proteins to the lung to achieve long-term systemic protein expression.

Regulation of Bcl-2 expression by dihydrotestosterone in hormone sensitive LNCaP-FGC prostate cancer cells.

PURPOSE: Up-regulation of the anti-apoptotic bcl-2 proto-oncogene is associated with androgen independent prostate cancer progression. This observation suggests that the expression of bcl-2 may be negatively regulated by androgens in prostate cancer cells. MATERIALS AND METHODS: The expression of the proto-oncogene bcl-2 was assessed in the hormone sensitive prostate cancer cell line LNCaP-FGC in the presence and absence of a physiological concentration of 1 nM. dihydrotestosterone (DHT). Sequence analysis of the bcl-2 promoter regions demonstrated the presence of 2 potential androgen response elements. Transient transfections of luciferase reporter constructs containing these potential androgen response elements into LNCaP-FGC cells in the presence and absence of DHT were performed. Steady-state transcripts of bcl-2 were assessed using RNase protection assays. RESULTS: Cells cultured in charcoal stripped serum in the presence of DHT resulted in down-regulation of bcl-2 protein. Down-regulation of bcl-2 protein and mRNA by DHT was inhibited by coincubation with the antiandrogen bicalutamide, an agent that competitively inhibits binding of DHT to androgen receptor. Luciferase reporter constructs containing candidate androgen response elements were transrepressed in the presence of DHT. Bcl-2 mRNA was also down-regulated by DHT and this down-regulation could not be abolished by cycloheximide. CONCLUSIONS: Together these results suggest that the suppression of bcl-2 expression by DHT in hormone sensitive LNCaP-FGC prostate cancer cells occurs directly. In addition, these results provide a possible mechanistic basis for the up-regulation (derepression) of bcl-2 observed in hormone independent prostate cancers.

Systemic gene therapy in human xenograft tumor models by liposomal delivery of the E1A gene.

The adenovirus type 5 E1A protein has been demonstrated to elicit antitumor effects through the induction of apoptosis, inhibition of cell cycle progression, induction of differentiated epithelial phenotypes, repression of oncogene expression and function, and sensitization to chemotherapeutic agents and radiation. These unique properties have led to use of the E1A gene in adenoviral and lipid-based gene therapy systems, and it has demonstrated antitumor effects in tumor xenograft model systems. However, the delivery systems used in those studies are best suited for local or intratumoral delivery rather than systemic delivery. Because the effective treatment of many primary tumors as well as metastatic disease requires systemic delivery systems, a novel gene delivery system composed of liposome/protamine/DNA (LPD) was investigated for systemic delivery of the E1A gene. Athymic nude mice bearing human breast (MDA-MB-361) or head and neck (WSUHN-31) tumor xenografts were treated i.v. with LPD-E1A, and the expression of E1A protein and effects on tumor growth were assessed. In the MDA-MB-361 breast model, expression of E1A protein was detected in the tumors after LPD-E1A treatment, which was associated with down-regulation of HER-2/neu protein expression and the presence of apoptotic cells. Tumor volume was also smaller in mice treated with LPD-E1A than in controls in both of the xenograft models. Lastly, LPD-E1A in combination with paclitaxel was more effective than LPD-E1A or paclitaxel alone in the MDA-MB-361 model. Additional preclinical and clinical development of LPD-E1A is warranted for the treatment of advanced or metastatic cancer.

Bcl-2 antagonizes the combined apoptotic effect of transforming growth factor-beta and dihydrotestosterone in prostate cancer cells.

BACKGROUND: We previously demonstrated that dihydrotestosterone (DHT) enhances transforming growth factor-beta (TGF-beta) -induced apoptosis in human prostate cancer cells (Endocrinology 2001;142:2419-2426). METHODS: In this study, the ability of the apoptosis suppressor bcl-2 to directly antagonize the combined apoptotic effect of TGF-beta and DHT in the androgen-sensitive LNCaP TbetaRII prostate cancer cells was examined. The previously cloned TGF-RbetaII receptor LNCaP cells, responsive to both TGF-beta and androgens, were engineered to overexpress the bcl-2 oncoprotein and the profile of apoptosis induction was analyzed in response to TGF-beta alone (5.0 ng/ml) or in combination with DHT (1 nM). RESULTS: Biological characterization of cloned LNCaP TbetaRII hygromycin/bcl-2 transfectants demonstrated that bcl-2 overexpression resulted in a significant inhibition of the combined TGF-beta and DHT apoptotic effect in prostate cancer cells (P < 0.01). Furthermore, molecular analysis indicated that this antagonistic effect of bcl-2 on apoptosis was due to partial suppression of TGF-beta and DHT-mediated induction of caspase-1 expression and activation in LNCaP TbetaRII-hygro/bcl-2 transfectants. These results support a potential bcl-2 interference with the TGF-beta and androgen apoptotic signaling in prostate cancer cells by means of an antagonistic effect on caspase-1 activation. CONCLUSION: This evidence may have mechanistic significance in understanding the contribution of bcl-2 overexpression in the development of androgen-independent prostate cancer by means of conferring resistance to TGF-beta-mediated apoptosis.