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Supplementary Materials and Methods

Frequency of germline ASPN D-repeat-length in JHH prostate cancer cases and controls.

Supplementary Table S2 shows bivariate and multivariable analyses of germline ASPN D13/14 compared to ASPN D13/13 for lymph node involvement and metastatic recurrence. Supplementary Table S3 show bivariate analyses of ASPN D genotypes/alleles for biochemical recurrence. Supplementary Table S4 shows multivariable analyses of ASPN D13/14 for biochemical recurrence.

This document contains supplemental details such as antibodies and primers, list of genes overrepresented in TWIST1 and TWIST1 mutants, IHC staining for TWIST1 in mouse prostate development, IHC staining for TWIST1 and HOXA9 in various mouse models of prostate cancer, correlation of TWIST1 and HOXA9 alteration with poor survival in human prostate cancer patients, IHC for TWIST1 and HOXA9 on primary tumors and bone metastasis from prostate cancer patients, IHC for HOXA9 on cell pellets expressing HOXA9 or control and on adult mouse prostate, data showing sufficiency of HOXA9 for some pro-metastatic behaviour in prostate cancer cells, data showing requirement of WDR5 and HOTTIP for TWIST1-dependent pro-metastatic behavior, ChIP data showing binding of TWIST1 and HOXA9 at the HOXA9 promoter, data showing effect of drugs that can inhibit HOXA9 on prostate cancer cell viability and pro metastatic behaviour.

ASPN antibody validation.

Figure S1: Comparison of Aspn+/+ and Aspn-/- mice. Figure S2: Representative gating of murine MSCs. Figure S3: ASPN restricts MSC differentiation. Figure S4: ASPN expression in cancer cell lines. Figure S5: ASPN increases cancer cell migration. Figure S6: ASPN expression in B6CaP allografts and organoids.

Tumor progression to metastasis is not cancer cell autonomous, but rather involves the interplay of multiple cell types within the tumor microenvironment. Here we identify asporin (ASPN) as a novel, secreted mesenchymal stromal cell (MSC) factor in the tumor microenvironment that regulates metastatic development. MSCs expressed high levels of ASPN, which decreased following lineage differentiation. ASPN loss impaired MSC self-renewal and promoted terminal cell differentiation. Mechanistically, secreted ASPN bound to BMP-4 and restricted BMP-4–induced MSC differentiation prior to lineage commitment. ASPN expression was distinctly conserved between MSC and cancer-associated fibroblasts (CAF). ASPN expression in the tumor microenvironment broadly impacted multiple cell types. Prostate tumor allografts in ASPN-null mice had a reduced number of tumor-associated MSCs, fewer cancer stem cells, decreased tumor vasculature, and an increased percentage of infiltrating CD8+ T cells. ASPN-null mice also demonstrated a significant reduction in lung metastases compared with wild-type mice. These data establish a role for ASPN as a critical MSC factor that extensively affects the tumor microenvironment and induces metastatic progression.Significance:These findings show that asporin regulates key properties of mesenchymal stromal cells, including self-renewal and multipotency, and asporin expression by reactive stromal cells alters the tumor microenvironment and promotes metastatic progression.

PDF file - 395KB, Figure S1. Pre-surgery plasma ddPCR analysis for PIK3CA mutations. Figure S2. Positive and negative controls for droplet thresholds and counts. Figure S3. Lower Limit of Detection for PIK3CA Exon 9. Supplementary Table S1: Primers used to amplify and sequence FFPE specimens. Supplementary Table S2: Primers and probes used for ddPCR on FFPE samples. Supplementary Table S3: Primers and probes for ddPCR of plasma DNA. Supplementary Table S4: Fractional abundance and 95% confidence intervals of positive ptDNA samples.

Purpose: Detecting circulating plasma tumor DNA (ptDNA) in patients with early-stage cancer has the potential to change how oncologists recommend systemic therapies for solid tumors after surgery. Droplet digital polymerase chain reaction (ddPCR) is a novel sensitive and specific platform for mutation detection.Experimental Design: In this prospective study, primary breast tumors and matched pre- and postsurgery blood samples were collected from patients with early-stage breast cancer (n = 29). Tumors (n = 30) were analyzed by Sanger sequencing for common PIK3CA mutations, and DNA from these tumors and matched plasma were then analyzed for PIK3CA mutations using ddPCR.Results: Sequencing of tumors identified seven PIK3CA exon 20 mutations (H1047R) and three exon 9 mutations (E545K). Analysis of tumors by ddPCR confirmed these mutations and identified five additional mutations. Presurgery plasma samples (n = 29) were then analyzed for PIK3CA mutations using ddPCR. Of the 15 PIK3CA mutations detected in tumors by ddPCR, 14 of the corresponding mutations were detected in presurgical ptDNA, whereas no mutations were found in plasma from patients with PIK3CA wild-type tumors (sensitivity 93.3%, specificity 100%). Ten patients with mutation-positive ptDNA presurgery had ddPCR analysis of postsurgery plasma, with five patients having detectable ptDNA postsurgery.Conclusions: This prospective study demonstrates accurate mutation detection in tumor tissues using ddPCR, and that ptDNA can be detected in blood before and after surgery in patients with early-stage breast cancer. Future studies can now address whether ptDNA detected after surgery identifies patients at risk for recurrence, which could guide chemotherapy decisions for individual patients. Clin Cancer Res; 20(10); 2643–50. ©2014 AACR.

Purpose: Mutations in the estrogen receptor (ER)α gene, ESR1, have been identified in breast cancer metastases after progression on endocrine therapies. Because of limitations of metastatic biopsies, the reported frequency of ESR1 mutations may be underestimated. Here, we show a high frequency of ESR1 mutations using circulating plasma tumor DNA (ptDNA) from patients with metastatic breast cancer.Experimental Design: We retrospectively obtained plasma samples from eight patients with known ESR1 mutations and three patients with wild-type ESR1 identified by next-generation sequencing (NGS) of biopsied metastatic tissues. Three common ESR1 mutations were queried for using droplet digital PCR (ddPCR). In a prospective cohort, metastatic tissue and plasma were collected contemporaneously from eight ER-positive and four ER-negative patients. Tissue biopsies were sequenced by NGS, and ptDNA ESR1 mutations were analyzed by ddPCR.Results: In the retrospective cohort, all corresponding mutations were detected in ptDNA, with two patients harboring additional ESR1 mutations not present in their metastatic tissues. In the prospective cohort, three ER-positive patients did not have adequate tissue for NGS, and no ESR1 mutations were identified in tissue biopsies from the other nine patients. In contrast, ddPCR detected seven ptDNA ESR1 mutations in 6 of 12 patients (50%).Conclusions: We show that ESR1 mutations can occur at a high frequency and suggest that blood can be used to identify additional mutations not found by sequencing of a single metastatic lesion. Clin Cancer Res; 22(4); 993–9. ©2015 AACR.

TWIST1 is a transcription factor critical for development that can promote prostate cancer metastasis. During embryonic development, TWIST1 and HOXA9 are coexpressed in mouse prostate and then silenced postnatally. Here we report that TWIST1 and HOXA9 coexpression are reactivated in mouse and human primary prostate tumors and are further enriched in human metastases, correlating with survival. TWIST1 formed a complex with WDR5 and the lncRNA Hottip/HOTTIP, members of the MLL/COMPASS–like H3K4 methylases, which regulate chromatin in the Hox/HOX cluster during development. TWIST1 overexpression led to coenrichment of TWIST1 and WDR5 as well as increased H3K4me3 chromatin at the Hoxa9/HOXA9 promoter, which was dependent on WDR5. Expression of WDR5 and Hottip/HOTTIP was also required for TWIST1-induced upregulation of HOXA9 and aggressive cellular phenotypes such as invasion and migration. Pharmacologic inhibition of HOXA9 prevented TWIST1-induced aggressive prostate cancer cellular phenotypes in vitro and metastasis in vivo. This study demonstrates a novel mechanism by which TWIST1 regulates chromatin and gene expression by cooperating with the COMPASS-like complex to increase H3K4 trimethylation at target gene promoters. Our findings highlight a TWIST1–HOXA9 embryonic prostate developmental program that is reactivated during prostate cancer metastasis and is therapeutically targetable. Cancer Res; 77(12); 3181–93. ©2017 AACR.

Supplementary Methods Figure S1 ESR1 Y537SY537N and D538G probes are mutation specific. Figure S2 Patient 1 and Patient 14's plasma DNA. Table S1 Additional patient characteristics. Table S2 Primers used in this study.

This document contains experimental details for microarray data acquisition and analysis, immunohistochemistry, immunofluorescence, western blotting, migration assay, invasion assay, anoikis assay, soft agar colony formation assay, RNA-immunoprecipitation, protein co-immunoprecipitation, Chromatin immunoprecipitation (ChIP), ChIP-Re-ChIP.

Supplementary Tables S6 shows bivariate analyses of the most common germline ASPN D genotypes/alleles for adverse pathology. Supplementary Table S7 shows multivariable analyses of ASPN D13/14 and Any 14 with lymph node involvement.

Supplementary Figure S6

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Supplementary Figure S5

This file consists of the Supplementary Materials and Methods and the Supplementary Figure Legends.

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Prostate cancer is a leading cause of cancer death in men due to the subset of cancers that progress to metastasis. Prostate cancers are thought to be hardwired to androgen receptor (AR) signaling, but AR-regulated changes in the prostate that facilitate metastasis remain poorly understood. We previously noted a marked reduction in secreted protein, acidic and rich in cysteine-like 1 (SPARCL1) expression during invasive phases of androgen-induced prostate growth, suggesting that this may be a novel invasive program governed by AR. Herein, we show that SPARCL1 loss occurs concurrently with AR amplification or overexpression in patient-based data. Mechanistically, we demonstrate that SPARCL1 expression is directly suppressed by androgen-induced AR activation and binding at the SPARCL1 locus via an epigenetic mechanism, and these events can be pharmacologically attenuated with either AR antagonists or HDAC inhibitors. We establish using the Hi-Myc model of prostate cancer that in Hi-Myc/Sparcl1−/− mice, SPARCL1 functions to suppress cancer formation. Moreover, metastatic progression of Myc-CaP orthotopic allografts is restricted by SPARCL1 in the tumor microenvironment. Specifically, we show that SPARCL1 both tethers to collagen in the extracellular matrix (ECM) and binds to the cell's cytoskeleton. SPARCL1 directly inhibits the assembly of focal adhesions, thereby constraining the transmission of cell traction forces. Our findings establish a new insight into AR-regulated prostate epithelial movement and provide a novel framework whereby SPARCL1 in the ECM microenvironment restricts tumor progression by regulating the initiation of the network of physical forces that may be required for metastatic invasion of prostate cancer. Cancer Res; 75(20); 4322–34. ©2015 AACR.

Intraductal cribriform (IDC) and invasive cribriform morphologies are associated with worse prostate cancer outcomes. Limited retrospective studies have associated IDC and cribriform morphology with germline mutations in DNA repair genes, particularly BRCA2. These findings, which prompted the National Comprehensive Cancer Network® (NCCN) Guidelines for Prostate Cancer and Genetic/Familial High- Risk Assessment to consider germline testing for individuals with IDC/cribriform histology, have been questioned in a recent prospective study. A deepened understanding of the molecular mechanisms driving disease aggressiveness in cribriform morphology is critical to provide more clarity in clinical decision making. This review summarizes the current understanding of IDC and cribriform prostate cancer, with an emphasis on clinical outcomes and molecular alterations.

Cribriform morphology, which includes intraductal carcinoma (IDCP) and invasive cribriform carcinoma, is an indicator of poor prognosis in prostate cancer. Phosphatase and tensin homologue (PTEN) loss is a predictor of adverse clinical outcomes. The association between PTEN expression and morphological patterns of prostate cancer is unclear.We explored the association between PTEN expression by immunohistochemistry, Gleason pattern 4 morphologies, IDCP and biochemical recurrence (BCR) in 163 radical prostatectomy specimens. IDCP was delineated from invasive cribriform carcinoma by p63 positive immunohistochemical staining in basal cells. Combined invasive cribriform carcinoma and IDCP were associated with a higher cumulative incidence of BCR [hazard ratio (HR) = 5.06; 2.21, 11.6, P 0.001]. When including PTEN loss in the analysis, invasive cribriform carcinoma remained predictive of BCR (HR = 3.72; 1.75, 7.94, P = 0.001), while PTEN loss within invasive cribriform carcinoma did not. Glomeruloid morphology was associated with lower odds of cancer stage pT3 and lower cumulative incidence of BCR (HR = 0.27; 0.088, 0.796, P = 0.018), while PTEN loss within glomeruloid morphology was associated with a higher cumulative incidence of BCR (HR = 4.07; 1.04, 15.9, P = 0.043).PTEN loss within glomeruloid pattern was associated with BCR. The presence of any cribriform pattern was associated with BCR, despite PTEN loss not significantly associated with invasive cribriform carcinoma. We speculate that other drivers independent from PTEN loss may contribute to poor prognostic features in cribriform carcinoma.

The ability to serially monitor tumor-derived cell-free DNA (cfDNA) brings with it the potential to measure response to anticancer therapies and detect minimal residual disease (MRD). This report describes a patient with HER2-positive metastatic breast cancer with an exceptional response to trastuzumab and nab-paclitaxel who remains in complete remission several years after cessation of therapy. Next-generation sequencing of the patient’s primary tumor tissue showed several mutations, including an oncogenic hotspot PIK3CA mutation. A sample of cfDNA was collected 6 years after her last therapy and then analyzed for mutant PIK3CA using digital PCR. No detectable mutations associated with the primary tumor were found despite assaying >10,000 genome equivalents, suggesting that the patient had achieved a molecular remission. Results of this case study suggest that serial monitoring of MRD using liquid biopsies could provide a useful method for individualizing treatment plans for patients with metastatic disease with extreme responses to therapy. However, large-scale clinical studies are needed to validate and implement these techniques for patient care.

Cancer-associated mutations in the spliceosome gene SF3B1 create a neomorphic protein that produces aberrant mRNA splicing in hundreds of genes, but the ensuing biologic and therapeutic consequences of this missplicing are not well understood. Here we have provided evidence that aberrant splicing by mutant SF3B1 altered the transcriptome, proteome, and metabolome of human cells, leading to missplicing-associated downregulation of metabolic genes, decreased mitochondrial respiration, and suppression of the serine synthesis pathway. We also found that mutant SF3B1 induces vulnerability to deprivation of the nonessential amino acid serine, which was mediated by missplicing-associated downregulation of the serine synthesis pathway enzyme PHGDH. This vulnerability was manifest both in vitro and in vivo, as dietary restriction of serine and glycine in mice was able to inhibit the growth of SF3B1(MUT) xenografts. These findings describe a role for SF3B1 mutations in altered energy metabolism, and they offer a new therapeutic strategy against SF3B1(MUT) cancers.

Tumor progression to metastasis is not cancer cell autonomous, but rather involves the interplay of multiple cell types within the tumor microenvironment. Here we identify asporin (ASPN) as a novel, secreted mesenchymal stromal cell (MSC) factor in the tumor microenvironment that regulates metastatic development. MSCs expressed high levels of ASPN, which decreased following lineage differentiation. ASPN loss impaired MSC self-renewal and promoted terminal cell differentiation. Mechanistically, secreted ASPN bound to BMP-4 and restricted BMP-4–induced MSC differentiation prior to lineage commitment. ASPN expression was distinctly conserved between MSC and cancer-associated fibroblasts (CAF). ASPN expression in the tumor microenvironment broadly impacted multiple cell types. Prostate tumor allografts in ASPN-null mice had a reduced number of tumor-associated MSCs, fewer cancer stem cells, decreased tumor vasculature, and an increased percentage of infiltrating CD8+ T cells. ASPN-null mice also demonstrated a significant reduction in lung metastases compared with wild-type mice. These data establish a role for ASPN as a critical MSC factor that extensively affects the tumor microenvironment and induces metastatic progression.Significance:These findings show that asporin regulates key properties of mesenchymal stromal cells, including self-renewal and multipotency, and asporin expression by reactive stromal cells alters the tumor microenvironment and promotes metastatic progression.

Intratumor heterogeneity is an important mediator of poor outcomes in many cancers, including breast cancer. Genetic subclones frequently contribute to this heterogeneity; however, their growth dynamics and interactions remain poorly understood. PIK3CA and HER2 alterations are known to coexist in breast and other cancers. Herein, we present data that describe the ability of oncogenic PIK3CA mutant cells to induce the proliferation of quiescent HER2 mutant cells through a cell contact–mediated mechanism. Interestingly, the HER2 cells proliferated to become the major subclone over PIK3CA counterparts both in vitro and in vivo. Furthermore, this phenotype was observed in both hormone receptor–positive and –negative cell lines, and was dependent on the expression of fibronectin from mutant PIK3CA cells. Analysis of human tumors demonstrated similar HER2:PIK3CA clonal dynamics and fibronectin expression. Our study provides insight into nonrandom subclonal architecture of heterogenous tumors, which may aid the understanding of tumor evolution and inform future strategies for personalized medicine.

Unlike several other tumor types, prostate cancer rarely responds to immune checkpoint blockade (ICB). To define tumor cell intrinsic factors that contribute to prostate cancer progression and resistance to ICB, we analyzed prostate cancer epithelial cells from castration-sensitive and -resistant samples using implanted tumors, cell lines, transgenic models and human tissue. We found that castration resulted in increased expression of interleukin-8 (IL-8) and its probable murine homolog Cxcl15 in prostate epithelial cells. We showed that these chemokines drove subsequent intratumoral infiltration of tumor-promoting polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), which was largely abrogated when IL-8 signaling was blocked genetically or pharmacologically. Targeting IL-8 signaling in combination with ICB delayed the onset of castration resistance and increased the density of polyfunctional CD8 T cells in tumors. Our findings establish a novel mechanism by which castration mediates IL-8 secretion and subsequent PMN-MDSC infiltration, and highlight blockade of the IL-8/CXCR2 axis as a potential therapeutic intervention. Drake and colleagues demonstrate that castration in prostate cancer models promotes IL-8 secretion and immunosuppressive myeloid-derived suppressor cell migration, and that inhibiting this axis in combination with checkpoint blockade can mitigate tumor progression.

// Ashley E. Ross 1, 2, 3, * , Robert M. Hughes 1, 2, 3, * , Stephanie Glavaris 1, 2, 3 , Kamyar Ghabili 1, 2, 3 , Ping He 3, 4 , Nicole M. Anders 3, 4 , Rana Harb 3 , Jeffrey J. Tosoian 1 , Luigi Marchionni 2, 3 , Edward M. Schaeffer 1, 2, 3 , Alan W. Partin 1, 2, 3 , Mohamad E. Allaf 1, 2, 3 , Trinity J. Bivalacqua 1, 2, 3 , Carolyn Chapman 1, 2, 3 , Tanya O’Neal 1, 2, 3 , Angelo M. DeMarzo 1, 3, 5 , Paula J. Hurley 1, 2, 3 , Michelle A. Rudek 3, 4, 6 and Emmanuel S. Antonarakis 1, 2, 3 1 James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, MD, USA 2 Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD, USA 3 Sidney Kimmel Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD, USA 4 Analytical Pharmacology Core Laboratory, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA 5 Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA 6 Department of Medicine, Division of Clinical Pharmacology, Johns Hopkins School of Medicine, Baltimore, MD, USA * These authors have contributed equally to this work Correspondence to: Emmanuel S. Antonarakis, email: eantona1@jhmi.edu Keywords: prostate cancer; Hedgehog; Sonidegib (LDE-225); GLI1 ; clinical trial Received: July 21, 2017 Accepted: September 15, 2017 Published: October 26, 2017 ABSTRACT Purpose: To determine the pharmacodynamic effects of Sonidegib (LDE-225) in prostate tumor tissue from men with high-risk localized prostate cancer, by comparing pre-surgical core-biopsy specimens to tumor tissue harvested post-treatment at prostatectomy. Methods: We conducted a prospective randomized (Sonidegib vs. observation) open-label translational clinical trial in men with high-risk localized prostate cancer undergoing radical prostatectomy. The primary endpoint was the proportion of patients in each arm who achieved at least a two-fold reduction in GLI1 mRNA expression in post-treatment versus pre-treatment tumor tissue. Secondary endpoints included the effect of pre-surgical treatment with Sonidegib on disease progression following radical prostatectomy, and safety. Results: Fourteen men were equally randomized (7 per arm) to either neoadjuvant Sonidegib or observation for 4 weeks prior to prostatectomy. Six of seven men (86%) in the Sonidegib arm (and none in the control group) achieved a GLI1 suppression of at least two-fold. In the Sonidegib arm, drug was detectable in plasma and in prostatic tissue; and median intra-patient GLI1 expression decreased by 63-fold, indicating potent suppression of Hedgehog signaling. Sonidegib was well tolerated, without any Grade 3-4 adverse events observed. Disease-free survival was comparable among the two arms (HR = 1.50, 95% CI 0.26–8.69, P = 0.65). Conclusions: Hedgehog pathway activity (as measured by GLI1 expression) was detectable at baseline in men with localized high-risk prostate cancer. Sonidegib penetrated into prostatic tissue and induced a >60-fold suppression of the Hedgehog pathway. The oncological benefit of Hedgehog pathway inhibition in prostate cancer remains unclear.

TWIST1 is a transcription factor critical for development that can promote prostate cancer metastasis. During embryonic development, TWIST1 and HOXA9 are coexpressed in mouse prostate and then silenced postnatally. Here we report that TWIST1 and HOXA9 coexpression are reactivated in mouse and human primary prostate tumors and are further enriched in human metastases, correlating with survival. TWIST1 formed a complex with WDR5 and the lncRNA Hottip/HOTTIP, members of the MLL/COMPASS–like H3K4 methylases, which regulate chromatin in the Hox/HOX cluster during development. TWIST1 overexpression led to coenrichment of TWIST1 and WDR5 as well as increased H3K4me3 chromatin at the Hoxa9/HOXA9 promoter, which was dependent on WDR5. Expression of WDR5 and Hottip/HOTTIP was also required for TWIST1-induced upregulation of HOXA9 and aggressive cellular phenotypes such as invasion and migration. Pharmacologic inhibition of HOXA9 prevented TWIST1-induced aggressive prostate cancer cellular phenotypes in vitro and metastasis in vivo. This study demonstrates a novel mechanism by which TWIST1 regulates chromatin and gene expression by cooperating with the COMPASS-like complex to increase H3K4 trimethylation at target gene promoters. Our findings highlight a TWIST1–HOXA9 embryonic prostate developmental program that is reactivated during prostate cancer metastasis and is therapeutically targetable. Cancer Res; 77(12); 3181–93. ©2017 AACR.

The combined contributions of oncogenes and tumor suppressor genes toward carcinogenesis remain poorly understood. Elucidation of cancer gene cooperativity can provide new insights leading to more effective use of therapies. We used somatic cell genome editing to introduce singly and in combination PIK3CA mutations (E545K or H1047R) with TP53 alterations (R248W or knockout), to assess any enhanced cancerous phenotypes. The non-tumorigenic human breast epithelial cell line, MCF10A, was used as the parental cell line, and resultant cells were assessed via various in vitro assays, growth as xenografts, and drug sensitivity assays using targeted agents and chemotherapies. Compared to single-gene-targeted cells and parental controls, cells with both a PIK3CA mutation and TP53 alteration had increased cancerous phenotypes including cell proliferation, soft agar colony formation, aberrant morphology in acinar formation assays, and genomic heterogeneity. Cells also displayed varying sensitivities to anti-neoplastic drugs, although all cells with PIK3CA mutations showed a relative increased sensitivity to paclitaxel. All cell lines remained non-tumorigenic. This cell line panel provides a resource for further elucidating cooperative genetic mediators of carcinogenesis and response to therapies.

BACKGROUND/PURPOSE: TrkA overexpression occurs in over 20% of breast cancers, including triple-negative breast cancers (TNBC), and has recently been recognized as a potential driver of carcinogenesis. Recent clinical trials of pan-Trk inhibitors have demonstrated targeted activity against tumors harboring NTRK fusions, a relatively rare alteration across human cancers. Despite this success, current clinical trials have not investigated TrkA overexpression as an additional therapeutic target for pan-Trk inhibitors. Here, we evaluate the cancerous phenotypes of TrkA overexpression relative to NTRK1 fusions in human cells and assess response to pharmacologic Trk inhibition. EXPERIMENTAL DESIGN/METHODS: To evaluate the clinical utility of TrkA overexpression, a panel of TrkA overexpressing cells were developed via stable transfection of an NTRK1 vector into the non-tumorigenic breast cell lines, MCF10A and hTERT-IMEC. A panel of positive controls was generated via stable transfection with a CD74-NTRK1 fusion vector into MCF10A cells. Cells were assessed via various in vitro and in vivo analyses to determine the transformative potential and targetability of TrkA overexpression. RESULTS: TrkA overexpressing cells demonstrated transformative phenotypes similar to Trk fusions, indicating increased oncogenic potential. TrkA overexpressing cells demonstrated growth factor-independent proliferation, increased PI3Kinase and MAPKinase pathway activation, anchorage-independent growth, and increased migratory capacity. These phenotypes were abrogated by the addition of the pan-Trk inhibitor, larotrectinib. In vivo analysis demonstrated increased tumorgenicity and metastatic potential of TrkA overexpressing breast cancer cells. CONCLUSIONS: Herein, we demonstrate TrkA overexpressing cells show increased tumorgenicity and are sensitive to pan-Trk inhibitors. These data suggest that TrkA overexpression may be an additional target for pan-Trk inhibitors and provide a targeted therapy for breast cancer patients.

Monotherapy with immune checkpoint inhibitors has generally been unsuccessful in men with advanced prostate cancer. Preclinical data support the notion that cryotherapy may improve immune-mediated and anti-tumor responses. The objective of this study was to assess the safety and feasibility of whole-prostate gland cryotherapy combined with pembrolizumab and androgen deprivation in men with oligometastatic hormone-sensitive prostate cancer.This single-institution, pilot trial recruited 12 patients with newly diagnosed oligometastatic prostate cancer between 2015 and 2016. Patients underwent whole-prostate cryoablation combined with short-term androgen deprivation (eight months) and pembrolizumab (6 doses). The primary clinical endpoints were the number of patients with a PSA level of0.6 ng/mL at one year and the frequency of adverse events. Other outcome measures included progression-free survival and systemic therapy-free survival. Exploratory analyses included PD-L1 protein expression.Forty two percent (5/12) of patients had a PSAs of0.6 ng/mL at one year though only 2 of these patients had recovered their testosterone at this time point. Median progression-free survival was 14 months, and median systemic therapy-free survival was 17.5 months. PD-L1 expression was not detectable by IHC in patients with evaluable tissue. All adverse events were grade ≤2, and there were no apparent complications from cryotherapy.Whole-prostate cryoablation combined with short-term androgen deprivation and pembrolizumab treatment was well tolerated and no safety concerns were observed in men with oligometastatic prostate cancer. Though local disease appeared effectively treated in the majority of men, the regimen only infrequency led to sustained disease control following testosterone recovery.

We report the establishment of B6CaP, an allograft tumor line from a Hi-Myc transgenic mouse that had been backcrossed onto C57BL/6J background. This tumor line grows subcutaneously in wildtype C57BL/6J immunocompetent mice, expresses AR, and has a luminal cytokeratin profile. When digested into single cells and injected via intracardiac injection, B6CaP produces metastatic widespread metastases including frequent bone lesions. Metastatic lesions occur most often in the femur, spine, and skull, and have a mixed osteolytic/osteoblastic phenotype. B6CaP allografts are androgen dependent, and regress after castration. However, castration resistant tumors regrow after 4-6 months and can be maintained as androgen-independent clones. This is the first example of a prostate-derived tumor line that shows frequent metastasis to bone and grows in an immunocompetent host, making this model useful for studying mechanisms of bone metastasis and tumor immune response.

PURPOSE Androgen receptor ( AR) gene alterations, including ligand-binding domain mutations and copy number (CN) gain, have yet to be fully established as predictive markers of resistance to enzalutamide and abiraterone in men with metastatic castration-resistant prostate cancer (mCRPC). The goal of this study was to validate AR gene alterations detected in cell-free DNA (cfDNA) as markers of enzalutamide and abiraterone resistance in patients with mCRPC. METHODS Patients with mCRPC (N = 62) were prospectively enrolled between 2014 and 2018. Blood was collected before therapies—enzalutamide (n = 25), abiraterone (n = 35), or enzalutamide and abiraterone (n = 2) —and at disease progression. We used deep next-generation sequencing to analyze cfDNA for sequence variants and CN status in AR and 45 additional cancer-associated genes. Primary end points were prostate-specific antigen response, progression-free survival (PFS), and overall survival (OS). RESULTS Elevated tumor-specific cfDNA (circulating tumor DNA) was associated with a worse prostate-specific antigen response (hazard ratio [HR], 3.17; 95% CI, 1.11 to 9.05; P = .031), PFS (HR, 1.76; 95% CI, 1.03 to 3.01; P = .039), and OS (HR, 2.92; 95% CI, 1.40 to 6.11; P = .004). AR ligand-binding domain missense mutations (HR, 2.51; 95% CI, 1.15 to 5.72; P = .020) were associated with a shorter PFS in multivariable models. AR CN gain was associated with a shorter PFS; however, significance was lost in multivariable modeling. Genetic alterations in tumor protein p53 (HR, 2.70; 95% CI, 1.27 to 5.72; P = .009) and phosphoinositide 3-kinase pathway defects (HR, 2.62; 95% CI, 1.12 to 6.10; P = .026) were associated with a worse OS in multivariable models. CONCLUSION These findings support the conclusion that high circulating tumor DNA burden is associated with worse outcomes to enzalutamide and abiraterone in men with mCRPC. Tumor protein p53 loss and phosphoinositide 3-kinase pathway defects were associated with worse OS in men with mCRPC. AR status associations with outcomes were not robust, and additional validation is needed.

BACKGROUND: Monotherapy with immune checkpoint inhibitors has generally been unsuccessful in men with advanced prostate cancer. Preclinical data support the notion that cryotherapy may improve immune-mediated and anti-tumor responses. The objective of this study was to assess the safety and feasibility of whole-prostate gland cryotherapy combined with pembrolizumab and androgen deprivation in men with oligometastatic hormone-sensitive prostate cancer. METHODS: This single-institution, pilot trial recruited 12 patients with newly diagnosed oligometastatic prostate cancer between 2015 and 2016. Patients underwent whole-prostate cryoablation combined with short-term androgen deprivation (eight months) and pembrolizumab (6 doses). The primary clinical endpoints were the number of patients with a PSA level of

Purpose: Mutations in the estrogen receptor (ER)α gene, ESR1, have been identified in breast cancer metastases after progression on endocrine therapies. Because of limitations of metastatic biopsies, the reported frequency of ESR1 mutations may be underestimated. Here, we show a high frequency of ESR1 mutations using circulating plasma tumor DNA (ptDNA) from patients with metastatic breast cancer. Experimental Design: We retrospectively obtained plasma samples from eight patients with known ESR1 mutations and three patients with wild-type ESR1 identified by next-generation sequencing (NGS) of biopsied metastatic tissues. Three common ESR1 mutations were queried for using droplet digital PCR (ddPCR). In a prospective cohort, metastatic tissue and plasma were collected contemporaneously from eight ER-positive and four ER-negative patients. Tissue biopsies were sequenced by NGS, and ptDNA ESR1 mutations were analyzed by ddPCR. Results: In the retrospective cohort, all corresponding mutations were detected in ptDNA, with two patients harboring additional ESR1 mutations not present in their metastatic tissues. In the prospective cohort, three ER-positive patients did not have adequate tissue for NGS, and no ESR1 mutations were identified in tissue biopsies from the other nine patients. In contrast, ddPCR detected seven ptDNA ESR1 mutations in 6 of 12 patients (50%). Conclusions: We show that ESR1 mutations can occur at a high frequency and suggest that blood can be used to identify additional mutations not found by sequencing of a single metastatic lesion. Clin Cancer Res; 22(4); 993–9. ©2015 AACR.

Ki-67 expression is correlated with cell proliferation and is a prognostic marker for various cancers; however, its function is unknown. Here we demonstrate that genetic disruption of Ki-67 in human epithelial breast and colon cancer cells depletes the cancer stem cell niche. Ki-67 null cells had a proliferative disadvantage compared to wildtype controls in colony formation assays and displayed increased sensitivity to various chemotherapies. Ki-67 null cancer cells showed decreased and delayed tumor formation in xenograft assays, which was associated with a reduction in cancer stem cell markers. Immunohistochemical analyses of human breast cancers revealed that Ki-67 expression is maintained at equivalent or greater levels in metastatic sites of disease compared to matched primary tumors, suggesting that maintenance of Ki-67 expression is associated with metastatic/clonogenic potential. These results elucidate Ki-67's role in maintaining the cancer stem cell niche, which has potential diagnostic and therapeutic implications for human malignancies.

Background Prostate cancer remains the second leading cause of cancer related death in men. Immune check point blocking antibodies have revolutionized treatment of multiple solid tumors, but results in prostate cancer remain marginal. Previous reports have suggested that local therapies, in particular cryoablation might increase tumor immunogenicity. In this work, we examine potential synergism between tumor cryoabalation and check point blocking antibodies. Methods FVB/NJ mice were injected subcutaneously into each flank with either 1 × 106 or 0.2 × 106 isogenic hormone sensitive Myc-Cap cells to establish synchronous grafts. Mice were treated with four intraperitoneal injections of anti-PD-1 (10 mg/kg), anti-CTLA-4 (1 mg/kg), or isotype control antibody with or without adjuvant cryoablation of the larger tumor graft and with or without neo-adjuvant androgen deprivation with degarelix (ADT). Mouse survival and growth rates of tumor grafts were measured. The immune dependency of observed oncological effects was evaluated by T cell depletion experiments. Results Treatment with anti-CTLA-4 antibody and cryoablation delayed the growth of the distant tumor by 14.8 days (p = 0.0006) and decreased the mortality rate by factor of 4 (p = 0.0003) when compared to cryoablation alone. This synergy was found to be dependent on CD3+ and CD8+ cells. Combining PD-1 blockade with cryoablation did not show a benefit over use of either treatment alone. Addition of ADT to anti-PD1 therapy and cryoablation doubled the time to accelerated growth in the untreated tumors (p = 0.0021) and extended survival when compared to cryoablation combined with ADT in 25% of the mice. Effects of combining anti-PD1 with ADT and cryoablation on mouse survival were obviated by T cell depletion. Conclusion Trimodal therapy consisting of androgen deprivation, cryoablation and PD-1 blockade, as well as the combination of cryoablation and low dose anti-CTLA-4 blockade showed that local therapies with cryoablation could be considered to augment the effects of checkpoint blockade in prostate cancer.

// Hong Yuen Wong 1 , Grace M. Wang 1 , Sarah Croessmann 1 , Daniel J. Zabransky 1 , David Chu 1 , Joseph P. Garay 1 , Justin Cidado 1,6 , Rory L. Cochran 1 , Julia A. Beaver 1 , Anita Aggarwal 2,3,4 , Min-Ling Liu 2,4 , Pedram Argani 1 , Alan Meeker 1 , Paula J. Hurley 1 , Josh Lauring 1 and Ben Ho Park 1,5 1 The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA 2 Veterans Affairs Medical Center, Washington, DC, USA 3 The Georgetown University, Washington, DC, USA 4 George Washington University School of Medicine, Washington, DC, USA 5 The Whiting School of Engineering, Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, USA 6 Present address: Oncology iMED, AstraZeneca, Waltham, MA, USA Correspondence to: Ben Ho Park, email: // Keywords : male breast cancer, Y chromosome, TMSB4Y, tumor suppressor, cancer genetics Received : November 30, 2015 Accepted : December 20, 2015 Published : December 23, 2015 Abstract Male breast cancer comprises less than 1% of breast cancer diagnoses. Although estrogen exposure has been causally linked to the development of female breast cancers, the etiology of male breast cancer is unclear. Here, we show via fluorescence in situ hybridization (FISH) and droplet digital PCR (ddPCR) that the Y chromosome was clonally lost at a frequency of ~16% (5/31) in two independent cohorts of male breast cancer patients. We also show somatic loss of the Y chromosome gene TMSB4Y in a male breast tumor, confirming prior reports of loss at this locus in male breast cancers. To further understand the function of TMSB4Y , we created inducible cell lines of TMSB4Y in the female human breast epithelial cell line MCF-10A. Expression of TMSB4Y resulted in aberrant cellular morphology and reduced cell proliferation, with a corresponding reduction in the fraction of metaphase cells. We further show that TMSB4Y interacts directly with β-actin, the main component of the actin cytoskeleton and a cell cycle modulator. Taken together, our results suggest that clonal loss of the Y chromosome may contribute to male breast carcinogenesis, and that the TMSB4Y gene has tumor suppressor properties.

Inflammation is associated with several diseases of the prostate including benign enlargement and cancer, but a causal relationship has not been established. Our objective was to characterize the prostate inflammatory microenvironment after infection with a human prostate-derived bacterial strain and to determine the effect of inflammation on prostate cancer progression. To this end, we mimicked typical human prostate infection with retrograde urethral instillation of CP1, a human prostatic isolate of Escherichia coli. CP1 bacteria were tropic for the accessory sex glands and induced acute inflammation in the prostate and seminal vesicles, with chronic inflammation lasting at least 1 year. Compared to controls, infection induced both acute and chronic inflammation with epithelial hyperplasia, stromal hyperplasia, and inflammatory cell infiltrates. In areas of inflammation, epithelial proliferation and hyperplasia often persist, despite decreased expression of androgen receptor (AR). Inflammatory cells in the prostates of CP1-infected mice were characterized at 8 weeks post-infection by flow cytometry, which showed an increase in macrophages and lymphocytes, particularly Th17 cells. Inflammation was additionally assessed in the context of carcinogenesis. Multiplex cytokine profiles of inflamed prostates showed that distinct inflammatory cytokines were expressed during prostate inflammation and cancer, with a subset of cytokines synergistically increased during concurrent inflammation and cancer. Furthermore, CP1 infection in the Hi-Myc mouse model of prostate cancer accelerated the development of invasive prostate adenocarcinoma, with 70% more mice developing cancer by 4.5 months of age. This study provides direct evidence that prostate inflammation accelerates prostate cancer progression and gives insight into the microenvironment changes induced by inflammation that may accelerate tumour initiation or progression.

Prostate cancer is one of the most common cancers in men in the United States. Comprehensive understanding of the biology contributing to prostate cancer will have important clinical implications. Animal models have greatly impacted our knowledge of disease and will continue to be a valuable resource for future studies. Herein, we describe a detailed protocol for the orthotopic engraftment of a murine prostate cancer cell line (Myc-CaP) into the anterior prostate of an immune competent mouse.

We previously reported that Polo-like kinase 2 (PLK2) is highly expressed in cells with defective mitochondrial respiration and is essential for their survival. Although PLK2 has been widely studied as a cell cycle regulator, we have uncovered an antioxidant function for this kinase that activates the GSK3-NRF2 signaling pathway. Here, we report that the expression of PLK2 is responsive to oxidative stress and that PLK2 mediates antioxidant signaling by phosphorylating GSK3, thereby promoting the nuclear translocation of NRF2. We further show that the antioxidant activity of PLK2 is essential for preventing p53-dependent necrotic cell death. Thus, the regulation of redox homeostasis by PLK2 promotes the survival of cells with dysfunctional mitochondria, which may have therapeutic implications for cancer and neurodegenerative diseases.

Purpose: Detecting circulating plasma tumor DNA (ptDNA) in patients with early-stage cancer has the potential to change how oncologists recommend systemic therapies for solid tumors after surgery. Droplet digital polymerase chain reaction (ddPCR) is a novel sensitive and specific platform for mutation detection. Experimental Design: In this prospective study, primary breast tumors and matched pre- and postsurgery blood samples were collected from patients with early-stage breast cancer (n = 29). Tumors (n = 30) were analyzed by Sanger sequencing for common PIK3CA mutations, and DNA from these tumors and matched plasma were then analyzed for PIK3CA mutations using ddPCR. Results: Sequencing of tumors identified seven PIK3CA exon 20 mutations (H1047R) and three exon 9 mutations (E545K). Analysis of tumors by ddPCR confirmed these mutations and identified five additional mutations. Presurgery plasma samples (n = 29) were then analyzed for PIK3CA mutations using ddPCR. Of the 15 PIK3CA mutations detected in tumors by ddPCR, 14 of the corresponding mutations were detected in presurgical ptDNA, whereas no mutations were found in plasma from patients with PIK3CA wild-type tumors (sensitivity 93.3%, specificity 100%). Ten patients with mutation-positive ptDNA presurgery had ddPCR analysis of postsurgery plasma, with five patients having detectable ptDNA postsurgery. Conclusions: This prospective study demonstrates accurate mutation detection in tumor tissues using ddPCR, and that ptDNA can be detected in blood before and after surgery in patients with early-stage breast cancer. Future studies can now address whether ptDNA detected after surgery identifies patients at risk for recurrence, which could guide chemotherapy decisions for individual patients. Clin Cancer Res; 20(10); 2643–50. ©2014 AACR.