<p>Supplementary Figure 3: IgG immunological response: IgG responses to AR LBD protein (panel A), PSA protein (panel B), and tetanus toxoid (panel C) were evaluated by Luminex. Sera samples were assessed at a 1:100 dilution from the time points indicated. Data were plotted over time, subtracting the pre-treatment value to evaluate change in post-treatment specimens.</p>
29 Background: Gain of function of androgen receptor (AR) and PI3K/Akt/mTOR pathway due to loss of PTEN function are interrelated determinants of AIPC progression and resistance to antiandrogens. We determined that histone deacetylase inhibitors (HDACi), known to regulate AR expression and transcriptional activity, restore sensitivity to bicalutamide (Bic) of AIPC cells and the combination is synergistic. We postulate that adding a dual inhibitor of PI3K/mTOR would potentiate growth inhibition and apoptotic response. Methods: Androgen-independent, PTEN null AI-LNCaP (AI-cells) and wt PTEN RV1-cell lines were treated for 72h with the HDACi Panobinostat (PAN), the dual PI3K/mTOR inhibitor BEZ235 (E) and Bic as single agents or in doublet or triplet combinations. Growth was measured by MTT assay, Akt/mTOR pathway target proteins p-Akt, p-4EBP1 and p-S6K by western blot. Activation of ligand-independent AR downstream targets: CDC20, IDI1, CDK1, UBE2C, PRDM4 by qRT-PCR. Apoptosis by oligonucleosome quantification by ELISA was compared to docetaxel. Results: In both cell lines, the IC50s were markedly reduced in response to the doublet combinations and further decreased by the triplet. The isobolograms showed synergy. The apoptosis response increased by two fold in AI and RV1 cells in response to the doublet PAN+E and by four fold with the addition of Bic in AI cells. Only E decreased the protein levels of p473-akt, p-4EBP1, p-S6K markedly while only PAN decreased AR and these levels were not affected by the combinations. However, the triplet but not the doublets decreased by 2-fold the expression of AR targets in AI-cells but not in RV1 cells. Conclusions: The combination of PAN+E is highly effective in AIPC cells regardless of PTEN status but the addition of Bic is essential to maximize the effect in PTEN null AI-cells, suggesting they are more dependent on aberrant activation of AR. [Table: see text] No significant financial relationships to disclose.
e16108 Background: Platelet-derived growth factor is frequently expressed in advanced prostate cancer (PC) lesions where it supports PC cell growth and neo-angiogenesis. Im. is a PDGF inhibitor that blocks cell cycle in G1-S due to MEK/erk inhibition. D blocks cell cycle progression in G2-M. Sequential block of the cell cycle progression in G2-M followed by G1-S may increase anti-tumor responses. The phase II study dose of sequential D on day 1 and Im started 24–36h later given daily for 14 d was established in a previous phase I. Methods: Eligibility: at least 2 prior hormone manipulations and up to one prior chemotherapy, PSA>5ng/ml, ECOG PS 0–2. Treatment schedule: D 70mg/m2 day 1 followed 24–36 hours later by Im 600mg PO daily × 14 days. Cycles were repeated every 21d until toxicity or progression. Pegfilgrastim was given each cycle for neutropenia prevention. A two steps design was planned to assess activity (PSA decline >50% and/or measurable or symptomatic response) and tolerance including interim analysis to determine if 37 patients (pts) should be enrolled. Results: Of 15 pts enrolled, 13 had metastasis and 5(33%) received prior chemotherapy. There were 98 cycles of trial therapy administered and 9 events (PSA or bone progression) registered at the time of analysis. Median baseline PSA 73,5ng/ml (2.1–1954.3). Median follow-up estimated by inverse Kaplan Meier: 308 days (CI95%, 133–482). Median of cycles administrated 6 (1–12). PSA decline >50% observed in 7/15pts (46.67%) of which 3 was >80% (20%). PSA decline <50%, observed in 6/15(40%). 2/15(15.3%) were non-responders. Pain scores improved in all symptomatic pts. Median duration of response was 162 days (42- 281). Estimated median progression free survival by Kaplan-Meier was 155 days (CI95%, 80–339). Toxicity: there was G1–2 fatigue, anorexia, weight change in 66% pts; nausea, vomiting, taste changes in 66% pts, anemia in 46% and neuropathy in 46% pts. G3 fatigue in 2 pts, neuropathy and CHF in 1 pt. No G4 toxicities were observed. Conclusions: Sequential and intermittent D every 21 days and Im for 14 days is tolerable and active by PSA decline and symptomatic improvement. Compared to previous report with weekly D and continuous Im, this alternative schedule appears to have similar activity with better tolerance. [Table: see text]
This study assesses the action of panobinostat, a histone deacetylase inhibitor (HDACI), in restoring sensitivity to bicalutamide in a castration-resistant prostate cancer (CRPC) model and the efficacy and safety of the panobinostat/bicalutamide combination in CRPC patients resistant to second-line antiandrogen therapy (2ndLAARx).The CWR22PC xenograft and isogenic cell line were tested for drug interactions on tumor cell growth and on the androgen receptor (AR), AR-splice variant7, and AR targets. A phase I trial had a 3 × 3 panobinostat dose-escalation design. The phase II study randomized 55 patients to panobinostat 40 mg (A arm) or 20 mg (B arm) triweekly ×2 weeks with bicalutamide 50 mg/day in 3-week cycles. The primary endpoint was to determine the percentage of radiographic progression-free (rPF) patients at 36 weeks versus historic high-dose bicalutamide.In the model, panobinostat/bicalutamide demonstrated synergistic antitumor effect while reducing AR activity. The dose-limiting toxicity was not reached. The probability of remaining rPF exceeded protocol-specified 35% in the A arm and 47.5% and 38.5% in the B arm. The probabilities of remaining rPF were 47.5% in the A arm and 38.5% in the B arm, exceeding the protocol-specified threshold of 35%. A arm/B arm: adverse events (AE), 62%/19%; treatment stopped for AEs, 27.5%/11.5%; dose reduction required, 41%/4%; principal A-arm grade ≥3 AEs, thrombocytopenia (31%) and fatigue (14%).The 40 mg panobinostat/bicalutamide regimen increased rPF survival in CRPC patients resistant to 2ndLAARx. Panobinostat toxicity was tolerable with dose reductions. Epigenetic HDACI therapy reduces AR-mediated resistance to bicalutamide in CRPC models with clinical benefit in patients. The combination merits validation using a second-generation antiandrogen.
Preclinical and retrospective data suggest that cytoreductive radical prostatectomy may benefit a subset of men who present with metastatic prostate cancer (mPCa). Herein, we report the results of the first planned Phase 1 study on cytoreductive surgery.From four institutions, 36 patients consented to the study. However, four did not complete surgery because of rapid disease progression (n = 3) and another because of an intraoperatively discovered pericolonic abscess. Men with newly diagnosed clinical mPCa to lymph nodes or bones were eligible. The primary endpoint was the rate of major perioperative complications (Clavien-Dindo Grade 3 or higher) occurring within 90 days of surgery.The mean age at surgery was 64.0 years. The 90-day overall complication rate was 31.2% (n = 10), of which two (6.25%) were considered major complications: one acute tubular necrosis requiring temporary dialysis and one death. In men with more than 6 months of follow-up, 67.9% had prostate specific antigen nadir ≤0.2 ng/mL, while one patient experienced a rapid rise in prostate specific antigen and another a widely disseminated disease that resulted in death 5 months after surgery. Altogether, these results demonstrate that cytoreductive radical prostatectomy is safe and surgically feasible in selected patients who present with mPCa . Yet, there may be a small subset of patients in whom surgery may cause a significant harm.Therefore, cytoreductive surgery in men with mPCa should be limited to clinical trials until robust data are available.
PURPOSE: 13 cis Retinoic acid (isotretinoin) is a retinoid with preclinical evidence of anti–prostate cancer activity. This phase II, cross-over, randomized study of advanced, predominantly androgen-dependent prostate cancer patients was designed to assess primarily the effect on prostate-specific antigen (PSA) decline and toxicity of adding isotretinoin to hormonal therapy and, secondarily, the potential antitumor activity of the combination. PATIENTS AND METHODS: Thirty-seven D0 to D2 patients were randomized soon after initiating luteinizing hormone–releasing hormone agonist with antiandrogen treatment to add (arm 1) or not (arm 2) isotretinoin from weeks 1 to 12. After cross-over on week 13, patients in arm 1 discontinued while patients in arm 2 added isotretinoin from weeks 14 to 25. Observation on hormonal therapy alone continued until week 49. RESULTS: Baseline and randomization median PSA for 30 assessable patients were, respectively, 34 and 18.2 ng/mL for arm 1 and 31 and 13.4 ng/mL for arm 2. Median PSA at week 13 was 0.5 ng/mL (range, < 0.05 to 136 ng/mL) for arm 1 and 0.7 ng/mL (range, < 0.05 to 4.4 ng/mL) for arm 2; at week 25, 0.1 ng/mL (range, < 0.05 to 121 ng/mL) and 0.4 ng/mL (range, < 0.05 to 3.1 ng/mL), respectively. At week 49, arm 1 had median PSA of 0.1 ng/mL (range, < 0.05 to 345 ng/mL) and arm 2, 0.3 ng/mL (range, < 0.05 to 8.8 ng/mL); seven of 15 and three of 15 patients, respectively, had undetectable PSA levels (P = .12). Frequent isotretinoin-related toxicity included grade 1 cheilitis (76%), skin dryness (43%), and elevated triglycerides (50%). CONCLUSION: Isotretinoin does not impair PSA decline or add significant toxicity to hormonal therapy. An adequately powered, randomized study would be required to determine whether the combination is superior to standard hormonal treatment.
101 Background: Increased androgen receptor (AR) and PI3K/Akt/mTOR signaling drive androgen-independent (AI) prostate cancer (PC) progression. AR splice variants (SV) lacking the ligand-binding domain activate ligand-independent transcriptional programs that support castration resistant proliferation and survival. Treatment of the androgen-dependent PTEN null LNCaP (AD-cells), its AI derivative (AI-cells) and wt PTEN RV1 cells with the dual PI3K/mTOR inhibitor BEZ235 (E) combined with the histone deacetylase inhibitor Panobinostat (PAN) induced synergistic growth inhibition and cell death in vitro and in vivo. The effect of these treatments on AR splicing is unknown. Methods: LNCaP AD, AI and RV1 cells were treated with PAN 20nM, E 350nM, rapamycin (Rapa) 20nM and PI3Ki BKM120 (K) 1.5µM for 24h. Total (t) AR, SV’s and AR targets mRNA were measured by qtPCR and western. RV1 xenografts received 3 weeks E 35mg/kg/d or PAN 10mg/kg/QOD or PAN+E. Results: Baseline levels of tAR mRNA in AI were higher than AD and RV1 cells while SV1, SV7 and SV5-7 were higher in RV1 than AD and AI cells. Treatment with E, Rapa and K increased both tAR and SV’s mRNA’s and AR and PSA proteins. In contrast, treatment with PAN reduced tAR and SV’s levels in AD and AI with no effect on RV1. PAN reduced the induction of tAR by Rapa or K in AD, AI and RV1 but did not abrogate induction of SV’s. PAN inhibition was sufficient to abrogate the effect of E and decrease tAR and SV’s levels as well as AR protein and AR canonical and non-canonical targets (PSA, TMPRSS2 and UBE2C) and PSA protein below baseline levels in all cells treated with PAN+E. Similarly, RV1 tumors treated with E had a 50% increase in tAR and 20% in SV5-7 but no induction of CDK1 or UBE2C and a 35% reduction in PSA while RV1 tumors treated with PAN+E showed 40% reduction in both SV’s 1 and 7 and downstream targets CDK1 and UBE2C. Conclusions: Inhibition of PI3K/mTOR with E increases overall levels of AR transcription that is more pronounced on SV’s and uncouples AR’s transcriptional activity on canonical downstream targets in vivo. PAN can abrogate the stimulation of E by decreasing both SV’s expression and AR transcriptional activity on non-canonical targets. These effects may underlie their synergistic growth inhibition.
Thirty percent of patients treated with curative intent for localized prostate cancer (PC) experience biochemical recurrence (BCR) with rising serum prostate-specific antigen (sPSA), and of these, approximately 50% succumb to progressive disease. More discriminatory staging procedures are needed to identify occult micrometastases that spawn BCR.PSA mRNA copies in pathologically normal pelvic lymph nodes (N0-PLN) from 341 localized PC patients were quantified by real-time reverse-transcriptase polymerase chain reaction. Based on comparisons with normal lymph nodes and PLN with metastases and on normalization to 5 x 10(6) glyceraldehyde-3'-phosphate dehydrogenase mRNA copies, normalized PSA copies (PSA-N) and a threshold of PSA-N 100 or more were selected for continuous and categorical multivariate analyses of biochemical failure-free survival (BFFS) compared with established risk factors.At median follow-up of 4 years, the BFFS of patients with PSA-N 100 or more versus PSA-N less than 100 was 55% and 77% (P = .0002), respectively. The effect was greatest for sPSA greater than 20 ng/mL, 25% versus 60% (P = .014), Gleason score 8 or higher, 21% versus 66% (P = .0002), stage T3c, 18% versus 64% (P = .001), and high-risk group (50% v 72%; P = .05). By continuous analysis PSA-N was an independent prognostic marker for BCR (P = .049) with a hazard ratio of 1.25 (95% CI, 1.001 to 1.57). By categorical analysis, PSA-N 100 or more was an independent variable (P = .021) with a relative risk of 1.98 (95% CI, 1.11 to 3.55) for BCR compared with PSA-N less than 100.PSA-N 100 or more is a new, independent molecular staging criterion for localized PC that identifies high-risk group patients with clinically relevant occult micrometastases in N0-PLN, who may benefit from additional therapy to prevent BCR.
Twenty-two adult patients with relapsed leukemia were given aziridinylbenzoquinone (AZQ) intravenously in a phase I clinical trial. AZQ was administered as a 30-minute infusion daily for 17 days. Courses were repeated when the bone marrow returned to normal cellularity and full recovery from nonhematologic toxicity had occurred. The initial dose of AZQ was 8 mg/m2/d x 7. The highest dose given was 28 mg/m2/d x 7. A maximum of three patients were treated at each dose level and patients received at least two courses at a given dose level before they were eligible to be escalated to the next higher available AZQ dose level. Nonhematologic side effects were mild and included nausea/vomiting (32%), mucositis (18%), and alopecia (0%). Dose-limiting toxicity was bone marrow aplasia at the 28 mg/m2/d x 7 level. No complete or partial responses were observed in this initial study. For phase II adult leukemia studies using this schedule, it is recommended that the AZQ dose should be 24 mg/m2/d.
