Elsa M. Li Ning Tapia

Combined Tumor Suppressor Defects Characterize Clinically Defined Aggressive Variant Prostate Cancers

Purpose: Morphologically heterogeneous prostate cancers that behave clinically like small-cell prostate cancers (SCPC) share their chemotherapy responsiveness. We asked whether these clinically defined, morphologically diverse, “aggressive variant prostate cancer (AVPC)” also share molecular features with SCPC. Experimental Design: Fifty-nine prostate cancer samples from 40 clinical trial participants meeting AVPC criteria, and 8 patient-tumor derived xenografts (PDX) from 6 of them, were stained for markers aberrantly expressed in SCPC. DNA from 36 and 8 PDX was analyzed by Oncoscan for copy number gains (CNG) and losses (CNL). We used the AVPC PDX to expand observations and referenced publicly available datasets to arrive at a candidate molecular signature for the AVPC. Results: Irrespective of morphology, Ki67 and Tp53 stained ≥10% cells in 80% and 41% of samples, respectively. RB1 stained <10% cells in 61% of samples and AR in 36%. MYC (surrogate for 8q) CNG and RB1 CNL showed in 54% of 44 samples each and PTEN CNL in 48%. All but 1 of 8 PDX bore Tp53 missense mutations. RB1 CNL was the strongest discriminator between unselected castration-resistant prostate cancer (CRPC) and the AVPC. Combined alterations in RB1, Tp53, and/or PTEN were more frequent in the AVPC than in unselected CRPC and in The Cancer Genome Atlas samples. Conclusions: Clinically defined AVPC share molecular features with SCPC and are characterized by combined alterations in RB1, Tp53, and/or PTEN. Clin Cancer Res; 22(6); 1520–30. ©2015 AACR.

Prostate cancer cell-stromal cell crosstalk via FGFR1 mediates antitumor activity of dovitinib in bone metastases.

Dovitinib is therapeutically active in a subset of patients with prostate cancer bone metastases, partly due to blockade of FGFR-mediated stromal-epithelial interactions in the bone microenvironment. Effective to the Bone Bone is the most common site of metastatic spread for prostate cancer, and tumors that have spread to the bone are usually very difficult to treat. Dovitinib is a recently developed drug that inhibits the fibroblast growth factor receptor. Now, Wan et al. have demonstrated that dovitinib is effective for some patients with prostate cancer that has spread to bone. The authors also identified an explanation for some of the observed antitumor effects by showing that the drug interferes with interactions between the prostate cancer cells and surrounding stromal cells in the bone microenvironment. Bone is the most common site of prostate cancer (PCa) progression to a therapy-resistant, lethal phenotype. We found that blockade of fibroblast growth factor receptors (FGFRs) with the receptor tyrosine kinase inhibitor dovitinib has clinical activity in a subset of men with castration-resistant PCa and bone metastases. Our integrated analyses suggest that FGF signaling mediates a positive feedback loop between PCa cells and bone cells and that blockade of FGFR1 in osteoblasts partially mediates the antitumor activity of dovitinib by improving bone quality and by blocking PCa cell–bone cell interaction. These findings account for clinical observations such as reductions in lesion size and intensity on bone scans, lymph node size, and tumor-specific symptoms without proportional declines in serum prostate-specific antigen concentration. Our findings suggest that targeting FGFR has therapeutic activity in advanced PCa and provide direction for the development of therapies with FGFR inhibitors.

Targeting Poly(ADP-Ribose) Polymerase and the c-Myb–Regulated DNA Damage Response Pathway in Castration-Resistant Prostate Cancer

The DNA damage response is an appealing target for androgen inhibitor–resistant prostate cancer. Improving Therapy in Prostate Cancer Blocking androgen receptor (AR) signaling is standard therapy for prostate cancer, but tumor growth often recurs. Li et al. examined the gene expression profile in patient samples of primary and metastatic prostate cancer from patients in which AR signaling was blocked. Metastatic disease, which is associated with androgen inhibitor–resistant relapse, correlated with increased expression of genes encoding proteins in the DNA damage response (DDR) and MYB expression. AR and c-Myb shared a subset of target genes that encode DDR proteins; thus, c-Myb may functionally substitute for AR in the regulation of their common DDR targets. Targeting proteins within the Myb-regulated network in combination with a poly[adenosine 5′-diphosphate (ADP)–ribose] polymerase (PARP) inhibitor, which compromises the DDR, generated synergistic lethality in prostate cancer cells in culture and in mouse xenografts, suggesting potential new options for prostate cancer patients. Androgen deprivation is the standard treatment for advanced prostate cancer (PCa), but most patients ultimately develop resistance and tumor recurrence. We found that MYB is transcriptionally activated by androgen deprivation therapy or genetic silencing of the androgen receptor (AR). MYB silencing inhibited PCa growth in culture and xenografts in mice. Microarray data revealed that c-Myb and AR shared a subset of target genes that encode DNA damage response (DDR) proteins, suggesting that c-Myb may supplant AR as the dominant regulator of their common DDR target genes in AR inhibition–resistant or AR-negative PCa. Gene signatures including AR, MYB, and their common DDR-associated target genes positively correlated with metastasis, castration resistance, tumor recurrence, and decreased survival in PCa patients. In culture and in xenograft-bearing mice, a combination strategy involving the knockdown of MYB, BRCA1, or TOPBP1 or the abrogation of cell cycle checkpoint arrest with AZD7762, an inhibitor of the checkpoint kinase Chk1, increased the cytotoxicity of the poly[adenosine 5′-diphosphate (ADP)–ribose] polymerase (PARP) inhibitor olaparib in PCa cells. Our results reveal new mechanism-based therapeutic approaches for PCa by targeting PARP and the DDR pathway involving c-Myb, TopBP1, ataxia telangiectasia mutated– and Rad3-related (ATR), and Chk1.

HTLV-1-associated infective dermatitis demonstrates low frequency of FOXP3-positive T-regulatory lymphocytes

BACKGROUND Human T-lymphotropic virus (HTLV)-1-associated infective dermatitis (ID) is a rare severe chronic eczema, considered as a harbinger for the development of cutaneous adult T-cell leukemia/lymphoma (ATLL) and/or HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). The pathogenesis of ID remains unclear. High numbers of peripheral blood CD4+ CD25+ FoxP3+ regulatory T cells (Tregs) have been reported in ATLL and HAM/TSP. OBJECTIVE To investigate the status of Tregs, unknown to date, and the histopathological features of ID. METHODS We studied 16 skin biopsies from 15 Peruvian adults and children with ID by immunohistochemistry. RESULTS Histopathological patterns were seborrheic dermatitis-like and lichenoid. Intraepidermal lymphocytes were conspicuous. The infiltrate was composed of a CD3+ T cell infiltrate with a predominance of CD8+ over CD4+ cells. CD4+ CD25+ FoxP3+ Tregs were rare and their numbers were significantly lower than those reported in other inflammatory dermatoses. CONCLUSION Tregs have an essential role in maintaining immune homeostasis of skin. Treg dysregulation ends in severe clinical manifestations. The clinical presentation of ID, with lesions resembling those seen in patients with atopic dermatitis and with mutations in the FoxP3 gene, is in agreement with a common Treg-deficient skin environment in these disorders, possibly secondary to HTLV-1 infection.

Tissue Effects in a Randomized Controlled Trial of Short-term Finasteride in Early Prostate Cancer

Background In the Prostate Cancer Prevention Trial, finasteride selectively suppressed low-grade prostate cancer and significantly reduced the incidence of prostate cancer in men treated with finasteride compared with placebo. However, an apparent increase in high-grade disease was also observed among men randomized to finasteride. We aimed to determine why and hypothesized that there is a grade-dependent response to finasteride. Methods From 2007 to 2012, we randomized dynamically by intranet-accessible software 183 men with localized prostate cancer to receive 5 mg finasteride or placebo daily in a double-blind study during the 4–6 weeks preceding prostatectomy. As the primary end point, the expression of a predefined molecular signature (ERβ, UBE2C, SRD5A2, and VEGF) differentiating high- and low-grade tumors in Gleason grade (GG) 3 areas of finasteride-exposed tumors from those in GG3 areas of placebo-exposed tumors, adjusted for Gleason score (GS) at prostatectomy, was compared. We also determined androgen receptor (AR) levels, Ki-67, and cleaved caspase 3 to evaluate the effects of finasteride on the expression of its downstream target, cell proliferation, and apoptosis, respectively. The expression of these markers was also compared across grades between and within treatment groups. Logistic regression was used to assess the expression of markers. Findings We found that the predetermined molecular signature did not distinguish GG3 from GG4 areas in the placebo group. However, AR expression was significantly lower in the GG4 areas of the finasteride group than in those of the placebo group. Within the finasteride group, AR expression was also lower in GG4 than in GG3 areas, but not significantly. Expression of cleaved caspase 3 was significantly increased in both GG3 and GG4 areas in the finasteride group compared to the placebo group, although it was lower in GG4 than in GG3 areas in both groups. Interpretation We showed that finasterides effect on apoptosis and AR expression is tumor grade dependent after short-term intervention. This may explain finasterides selective suppression of low-grade tumors observed in the PCPT.

Performance of a Prostate Cancer Genomic Classifier in Predicting Metastasis in Men with Prostate-specific Antigen Persistence Postprostatectomy

BACKGROUND Prostate cancer patients who have a detectable prostate-specific antigen (PSA) postprostatectomy may harbor pre-existing metastatic disease. To our knowledge, none of the commercially available genomic biomarkers have been investigated in such men. OBJECTIVE To evaluate if a 22-gene genomic classifier can independently predict development of metastasis in men with PSA persistence postoperatively. DESIGN, SETTING, AND PARTICIPANTS A multi-institutional study of 477 men who underwent radical prostatectomy (RP) between 1990 and 2015 from three academic centers. Patients were categorized as detectable PSA (n=150) or undetectable (n=327) based on post-RP PSA nadir ≥0.1 ng/ml. OUTCOME MEASUREMENTS AND STATISITICAL ANALYSIS Cumulative incidence curves for metastasis were constructed using Fine-Gray competing risks analysis. Penalized Cox univariable and multivariable (MVA) proportional hazards models were performed to evaluate the association of the genomic classifier with metastasis. RESULTS AND LIMITATIONS The median follow-up for censored patients was 57 mo. The median time from RP to first postoperative PSA was 1.4 mo. Detectable PSA patients were more likely to have higher adverse pathologic features compared with undetectable PSA patients. On MVA, only genomic high-risk (hazard ratio [HR]: 5.95, 95% confidence interval [CI]: 2.02-19.41, p=0.001), detectable PSA (HR: 4.26, 95% CI: 1.16-21.8, p=0.03), and lymph node invasion (HR: 12.2, 95% CI: 2.46-70.7, p=0.003) remained prognostic factors for metastasis. Among detectable PSA patients, the 5-yr metastasis rate was 0.90% for genomic low/intermediate and 18% for genomic high risk (p<0.001). Genomic high risk remained independently prognostic on MVA (HR: 5.61, 95% CI: 1.48-22.7, p=0.01) among detectable PSA patients. C-index for Cancer of the Prostate Risk Assessment Postsurgical score, Gandaglia nomogram, and the genomic classifier plus either Cancer of the Prostate Risk Assessment Postsurgical score or Gandaglia were 0.69, 0.68, and 0.82 or 0.81, respectively. Sample size was a limitation. CONCLUSIONS Despite patients with a detectable PSA harboring significantly higher rates of aggressive clinicopathologic features, Decipher independently predicts for metastasis. Prospective validation of these findings is warranted and will be collected as part of the ongoing randomized trial NRG GU-002. PATIENT SUMMARY Decipher independently predicted metastasis for patients with detectable prostate-specific antigen after prostatectomy.

Positive margin length and highest Gleason grade of tumor at the margin predict for biochemical recurrence after radical prostatectomy in patients with organ-confined prostate cancer

BackgroundTo evaluate the pathologic features after radical prostatectomy to determine if the length of positive surgical margin (PSM) and the highest Gleason grade within the tumor at the PSM could risk stratify patients for biochemical recurrence (BCR).MethodsWe performed a retrospective, matched, cohort study to identify patients with pathologically organ-confined (pT2) tumors and negative nodes (pN0/Nx), receiving no adjuvant therapy. Specimens underwent single pathologist review. BCR-free survival was estimated using the Kaplan–Meier method and compared between subgroups using two-sided log-rank test. Using Classification and Regression Tree analysis (CART), we identified an optimal cutoff for the PSM length which differentiated risk for BCR. Cox proportional hazards regression models were fit to assess the association between variables and BCR-free survival.ResultsTwo-hundred PSM patients were matched to 200 patients with negative surgical margins (NSM). Median follow-up was 64 months. 5 year BCR-free survival was 90% (95% CI 84–97%) in the NSM group and 70% (95% CI 63–79%) in the PSM group. There was an increased risk of BCR with any PSM. Multivariable analysis demonstrated an association with length of PSM ( > 1 mm vs. ≤ 1 mm, HR 2.29; 95% CI 1.2–4.5) and having a highest Gleason grade of the cancer focus at the margin ≥ 4 (HR 6.8; 95% CI 1.6–29).ConclusionsWe demonstrated that patients with pathologic T2 tumors with PSM > 1 mm or a Gleason grade of tumor focus at the margin ≥ 4 are at elevated risk for BCR. However, this study suggests that patients with pT2 tumors with positive surgical margins have a relatively low risk of biochemical recurrence and adjuvant radiation may be over treating this sub population. The subsets at greatest risk for BCR may benefit from more frequent PSA monitoring to direct salvage therapies.

MP64-12 ASSESSING DECIPHER FOR PREDICTING LYMPH NODE POSITIVE DISEASE AMONG MEN DIAGNOSED WITH INTERMEDIATE RISK DISEASE TREATED WITH PROSTATECTOMY AND EPLND

INTRODUCTION AND OBJECTIVES: Available recommendations for extended lymph node dissection [eLND] at radical prostatectomy [RP] do not consider patient age, but rely on cancer characteristics only. However, for patients with limited life-expectancy, eLND might be an overtreatment. We hypothesized that limited life-expectancy of older RP candidates might dilute any beneficial effect of eLND in terms of cancer staging and outcomes. Therefore, we aimed at assessing the differential effect of age on the risk of lymph node invasion [LNI] and mortality due to cause other than prostate cancer [OCM] in order to define an age limit above which eLND might be avoided. METHODS: We included 3,906 patients diagnosed with prostate cancer and treated with RP and an anatomically defined eLND at a single Institution. Logistic and Cox regression analyses were used to compute the risk of LNI at eLND and the risk of OCM 10 years after RP. Predictors of LNI were chosen in compliance with guidelines-recommended models and were PSA, primary and secondary biopsy Gleason score and clinical stage. Predictors of OCM were age at surgery, Charlson comorbidity index [CCI] and year of surgery. Locally weighted scatterplot smoothing method was used to graphically examine the differential effect of age on the risk of LNI and OCM. RESULTS: Median age was 65 years. LNI rate was 12%. 10year OCM rate was 5%. PSA (odd ratio [OR] 1.06; p<0.001), primary (OR 5.32; p<0.001) and secondary (OR 2.27; p<0.001) biopsy Gleason score 4 as well as clinical stage cT2 (OR 2.4; p<0.001) and cT3 (OR 3.24; p<0.001) were associated with higher LNI risk. Age (hazard ratio [HR] 1.11; p<0.001) and CCI (HR 1.28; p1⁄40.03) were associated with higher OCM risk. Year of surgery (HR 0.92; p<0.001) was associated with lower OCM risk. For patients aged 75 or younger, the risk of LNI (811%) was higher than the risk of OCM (<1-10%; Figure 1). Conversely, for patients aged 76 or older the risk of LNI (11-17%) was equal or lower than the risk of OCM (11-26%). CONCLUSIONS: For RP candidates older than 75 years, the risk of OCM equals or exceeds the risk of LNI. Such relatively high risk of OCM compared to the relatively low risk of LNI casts relevant doubts on any potential benefit related to eLND at RP. These findings argue against the routine use of eLND for older patients in clinical practice.

Abstract A03: Analyses of a prostate cancer patient-derived xenografts series, a resource for translational research

Patients with metastatic prostate cancer (PCa) have effective therapy options, but none of them are curative. Thus, their mortality rates are persistently high. Essential to furthering our progress in PCa research and therapy development is a spectrum of models that reflect the heterogeneity of the disease at each tumor site as well as the different histological variants of PCa (e.g., adenocarcinoma, small cell carcinoma). To address this challenge, we developed a strategy to establish PCa patient-derived xenografts (PDXs), using PCa tissue specimens taken from PCa sites demonstrating clinical progression. This approach provided a diverse repository of PDXs that can be linked prospectively with clinical progression and led to the identification of clinically relevant therapy targets and have proven valuable for testing drugs. We studied the first 50 PDXs developed under our program to a) define the histopathological features of paired human PCa and corresponding PDXs applying the clinically defined morphological characterization groupings of human cancer to the PDX tumors; b) assess the expression of genes known to play roles in PCa pathogenesis (e.g., androgen receptor, PTEN, ETS gene fusions) in PDXs and the human tumors of origin using immunohistochemistry and fluorescence in situ hybridization and c) perform array comparative genomic hybridization to 42 PDXs. We found that the histopathological and molecular pattern of these PDXs maintain the fidelity with the human tumor of origin. Furthermore, of the 50 cases studied, 32 (64%) were adenocarcinomas, and 16 (32%) were small cell carcinomas, poorly differentiated neuroendocrine carcinomas or mixed adenocarcinoma/ small cell carcinomas. In our cohort, we also have one sarcomatoid tumor and one ductal adenocarcinoma. Of the 32 adenocarcinomas in this cohort, 26 were AR-positive (81%), and 11 of the 27 AR-positive adenocarcinomas (41%) had aberrant expression of genes frequently involved in recurrent rearrangement (e.g., ERG, ETV1, ETV5). Also, SCCs and poorly differentiated neuroendocrine carcinomas did not express AR and were negative for ERG. This distribution recapitulates that of human PCa in the general population. Comparative genomic hybridization demonstrated gains and losses previously reported in PCa with a defined cluster of genomic aberrations. Significant differences in oncogenic pathways activation in pairs of PDXs derived from different areas of the same tumor suggesting divergent cellular progression. Finally, using this platform, we identified a focal deletion of speckle-type POZ protein-like (SPOPL) gene in 7/28 PDX. SPOPL is a MATH-BTB protein that shares an overall 85% sequence identity with SPOP (a SPOPL paralog). SPOP was recently reported to be mutated in about 8% of PCa and to define a molecular subclass of PCa. No mutations were found in SPOP in our cohort. In support of our findings, deletions on SPOPL were also found in about 7% of the PCa in TCGA data suggesting that our cohort is a reliable platform for discovery. In conclusion, we have developed a dynamic repository of clinically annotated samples that can be used as a discovery platform. Furthermore, these clinically annotated samples can be linked prospectively to clinical progression/response to therapy and thus will help define therapeutic targets for subpopulations of men and to identify likely responders to previous and upcoming therapies. Citation Format: Nallasivam Palanisamy, Jun Yang, Xinhai Wan, Elsa M. li Ning Tapia, John C. Araujo, Eleni Efstathiou, Estefania Labanca, Louis Pisters, Ana Aparicio, Ritu Bhalla, Scott Tomlins, Lakshmi P. Kunju, Arul Chinnaiyan, Christopher J. Logothetis, Patricia Troncoso, Nora M. Navone. Analyses of a prostate cancer patient-derived xenografts series, a resource for translational research. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A03.

Abstract 2436: Fibroblast growth factor receptor blockade in prostate cancer bone metastases.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Castrate-resistant progression and bone metastases (BM) are hallmarks of advanced prostate cancer (PCa) for which there is no definitive cure. We previously reported that human PCa BM highly express fibroblast growth factor (FGF)-9 (J Clin Invest. 2008;118:2697). We now discovered that human PCa xenografts growing in the bone of mice induce bone cells to express components of the FGF/FGF receptor (FGFR) complex, Fgfr1, Fgfr2 and Fgf-2, as assessed by mouse-specific RT-PCR in bone bearing MDA PCa 118b tumors and in the contralateral bone (P 20 weeks in a subset of patients (∼25%). Dovitinib inhibits vascular endothelial growth factor receptors (VEGFRs) 1-3, with IC50s (∼10 nM) similar to those of FGFR1-3. To assess the relative antitumor activity of FGFR blockade (with respect to VEGFR), we tested a TKI, AZD4547 (AstraZeneca), which inhibits FGFR1-3 (IC50s <3 nM) but not VEGFRs. We found that AZD4547 had antitumor activity against MDA PCa 118b bone tumors and reduces the volume of normal bones and of FGFR1 expression in tumor-associated bone cells (P<0.001). Accordingly, we observed a decrease in the blood levels of bone-specific alkaline phosphatase of men enrolled in the dovitinib trial, and this reduction was associated with the time men remained on treatment (P=0.035) (eg, those who benefited from treatment). No association was found between PSA blood levels or urinary N-telopeptides and response to therapy. Finally, we found that PCa cells and/or osteoblasts express FGFR1 in a fraction of human PCa BM (assessed by immunohistochemistry). We conclude that dovitinib therapy benefits a subset (∼25%) of men with PCa BM and that FGFR blockade contributes to this antitumor effect, at least partially, by blockade of FGFR-mediated PCa-bone cross talk. Ongoing studies focused on further understanding the mechanism of this antitumor activity will help identify likely responders and elucidate FGF signaling interaction with other candidate targets (eg, AR, c-Met, IGF, Src, VEGF). Citation Format: Xinhai Wan, Paul Corn, Jun Yang, Eleni Efstathiou, Elsa M. Li Ning Tapia, Fen Wang, Wallace McKeehan, Christopher Logothetis, Patricia Troncoso, Nora M. Navone. Fibroblast growth factor receptor blockade in prostate cancer bone metastases. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2436. doi:10.1158/1538-7445.AM2013-2436 [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00831792&atom=%2Fcanres%2F73%2F8_Supplement%2F2436.atom