Effect of Radical Prostatectomy on Survival for Men with High-risk Nonmetastatic Prostate Cancer Features Selected According to STAMPEDE Criteria: An EMPaCT Study.

BACKGROUND AND OBJECTIVE: A meta-analysis of two randomized STAMPEDE platform trials revealed that 3 yr of abiraterone acetate in addition to androgen deprivation therapy and radiation therapy significantly improved metastasis-free and overall survival (OS) in high-risk nonmetastatic prostate cancer (PCa) and should be considered a new standard of care. The aim of our study was to assess long-term cancer-specific survival (CSS) and OS for surgically treated patients with newly diagnosed nonmetastatic node-negative PCa meeting the STAMPEDE criteria for high risk. METHODS: This was a retrospective, multicenter cohort study of patients with European Association of Urology (EAU) high-risk PCa who underwent radical prostatectomy and extended pelvic lymph node dissection. CSS was assessed using cumulative incidence curves and the Kaplan-Meier method was used to evaluate OS. We used a Fine and Gray model to evaluate the prognostic value of STAMPEDE high-risk factors (SHRFs) for CSS, and a Cox proportional-hazards model to assess the association of SHRFs with OS. KEY FINDINGS AND LIMITATIONS: A total of 2994 patients with EAU high-risk PCa were divided into groups with 0, 1, 2, or 3 SHRFs. The 10-yr survival estimates for patients with 0-1 versus 2-3 SHRFs were 95% versus 82% for CSS and 81% versus 64% for OS (both p < 0.0001). In comparison to patients with 0 SHRFs, hazard ratios were 1.2 (p = 0.5), 3.9 (p < 0.0001), and 5.5 (p < 0.0001) for CSS, and 1.1 (p = 0.4), 2.2 (p < 0.0001), and 2.5 (p = 0.0004) for OS for patients with 1, 2, and 3 SHRFs, respectively. CONCLUSIONS AND CLINICAL IMPLICATIONS: Our results confirm that the STAMPEDE high-risk criteria identify a subgroup of patients with highly aggressive PCa features and adverse long-term oncological outcomes. This population is likely to benefit most from aggressive multimodal treatment. Nevertheless, we have shown for the first time that surgery remains a viable treatment option for patients with STAMPEDE high-risk PCa. PATIENT SUMMARY: Prostate cancer that meets the high-risk definitions from the STAMPEDE trial is an aggressive type of cancer. Our results for long-term cancer control outcomes indicate that surgery is a viable option for the subgroup of patients with this type of prostate cancer.

Safety and quality of cystectomy and pelvic lymph node dissection after neoadjuvant durvalumab and cisplatin/gemcitabine.

OBJECTIVE: To report on the surgical safety and quality of pelvic lymph node dissection (PLND) in patients treated with radical cystectomy (RC) and PLND for muscle-invasive bladder cancer (MIBC) after neoadjuvant chemo-immunotherapy. PATIENTS AND METHODS: The Swiss Group for Clinical Cancer Research (SAKK) 06/17 was an open-label single-arm phase II trial including 61 cisplatin-fit patients with clinical stage (c)T2-T4a cN0-1 operable urothelial MIBC or upper urinary tract cancer. Patients received neoadjuvant cisplatin/gemcitabine and durvalumab followed by surgery. Prospective quality assessment of surgeries was performed via central review of intraoperative photographs. Postoperative complications were assessed using the Clavien-Dindo Classification. Data were analysed descriptively. RESULTS: A total of 50 patients received RC and PLND. All patients received neoadjuvant chemo-immunotherapy. The median (interquartile range) number of lymph nodes removed was 29 (23-38). No intraoperative complications were registered. Grade ≥III postoperative complications were reported in 12 patients (24%). Complete nodal dissection (100%) was performed at the level of the obturator fossa (bilaterally) and of the left external iliac region; in 49 patients (98%) at the internal iliac region and at the right external iliac region; in 39 (78%) and 38 (76%) patients at the right and left presacral level, respectively. CONCLUSION: This study supports the surgical safety of RC and PLND following neoadjuvant chemo-immunotherapy in patients with MIBC. The extent and completeness of protocol-defined PLND varies between patients, highlighting the need to communicate and monitor the surgical template.

Stromal-epithelial interaction induces GALNT14 in prostate carcinoma cells.

Introduction: Cell-cell communication is an important process in healthy tissue but also gains enhanced attention regarding pathological tissue. To date, the tumor microenvironment is gradually brought into focus when studying tumorigenesis. In the prostate gland, stromal and epithelial cells greatly interact to maintain homeostasis or tissue integrity. This study focuses on an indirect communication via soluble factors. Methods: To investigate the cell-cell interaction via soluble factors, the prostate carcinoma cell line LNCaP and the stromal primary cells p21 were co-cultured without direct contact and RNA was isolated at defined time points. Differences in gene expression were finally analyzed by RNA sequencing. Results: RNA sequencing revealed a time-depending differential expression profile. Selected factors were subsequently characterized at molecular level and analyzed in human prostate tissue of different developmental stages as well as pathology. GALNT14 was one of the highest induced co-culture-specific genes in LNCaP cells. Detection in healthy tissue and BPH revealed an age-dependent decrease in GALNT14 expression. Moreover, in prostate carcinoma, GALNT14 expression heavily varied independent of the Gleason score. Conclusion: Overall, this work provides a basis for further studies related to paracrine stromal-epithelial interaction in prostate carcinoma and highlights the importance of GALNT14.

Perioperative Chemoimmunotherapy With Durvalumab for Muscle-Invasive Urothelial Carcinoma: Primary Analysis of the Single-Arm Phase II Trial SAKK 06/17.

PURPOSE: The integration of immunotherapy in the perioperative setting of muscle-invasive urothelial carcinoma (MIUC) appears promising. SAKK 06/17 investigated the addition of neoadjuvant durvalumab to gemcitabine/cisplatin (GC) chemotherapy followed by radical surgery and adjuvant checkpoint inhibition with durvalumab. PATIENTS AND METHODS: SAKK 06/17 was an investigator-initiated, open-label, single-arm phase II study including cisplatin-fit patients with stage cT2-T4a cN0-1 operable MIUC. Four cycles of neoadjuvant GC in combination with four cycles of durvalumab (start with GC cycle 2) were administered, followed by radical surgery. Adjuvant durvalumab was given for 10 cycles. The primary end point was event-free survival (EFS) at 2 years. RESULTS: Sixty one patients were accrued at 12 sites. The full analysis set consisted of 57 patients, 54 (95%) had bladder cancer. Median follow-up was 40 months. The primary end point was met, with EFS at 2 years of 76% (one-sided 90% CI [lower bound], 67%; two-sided 95% CI, 62 to 85). EFS at 3 years was 73% (95% CI, 59 to 83). Complete pathologic response in resected patients (N = 52) was achieved in 17 patients (33%), and 31 (60%) had pathologic response

Novel sequential treatment strategy for patients with muscle-invasive bladder cancer (MIBC): intravesical recombinant BCG, followed by neoadjuvant chemoimmunotherapy, radical cystectomy plus pelvic lymphadenectomy and adjuvant immunotherapy - protocol of a multicentre, single arm phase 2 trial (SAKK 06/19).

INTRODUCTION: The combination of checkpoint inhibition and cisplatin-based chemotherapy is investigated in muscle invasive bladder cancer (MIBC) and results from phase 2 trials have been presented. Intravesical BCG has been used for non-MIBC (NMIBC) in patients with carcinoma in situ and high-grade Ta/T1 tumours. BCG induces innate and adapted immune response and upregulation of PD-L1 in preclinical models. The proposed trial is intended to implement a new immuno-immuno-chemotherapy induction therapy for MIBC. The combination of BCG and checkpoint inhibition with chemotherapy aims at higher intravesical responses and better local and systemic control of disease. METHODS AND ANALYSIS: SAKK 06/19 is an open-label single-arm phase II trial for patients with resectable MIBC T2-T4a cN0-1. Intravesical recombinant BCG (rBCG: VPM1002BC) is applied weekly for three instillations followed by four cycles of neoadjuvant cisplatin/gemcitabine every 3 weeks. Atezolizumab 1200 mg every 3 weeks is started together with rBCG and given for four cycles. All patients then undergo restaging and radical cystectomy and pelvic lymphadenectomy. Atezolizumab is continued as maintenance therapy after surgery every 3 weeks for 13 cycles. Pathological complete remission is the primary endpoint. Secondary endpoints include pathological response rate (

Epiregulin expression and secretion is increased in castration-resistant prostate cancer.

Introduction: In prostate cancer, long-term treatment directed against androgens often leads to the development of metastatic castration-resistant prostate cancer, which is more aggressive and not curatively treatable. Androgen deprivation results in elevated epiregulin expression in LNCaP cells which is a ligand of EGFR. This study aims to reveal the expression and regulation of epiregulin in different prostate cancer stages enabling a more specific molecular characterization of different prostate carcinoma types. Methods: Five different prostate carcinoma cell lines were used to characterize the epiregulin expression on the RNA and protein levels. Epiregulin expression and its correlation with different patient conditions were further analyzed using clinical prostate cancer tissue samples. Additionally, the regulation of epiregulin biosynthesis was examined at transcriptional, post-transcriptional and release level. Results: An increased epiregulin secretion is detected in castration-resistant prostate cancer cell lines and prostate cancer tissue samples indicating a correlation of epiregulin expression with tumor recurrence, metastasis and increased grading. Analysis regarding the activity of different transcription factors suggests the involvement of SMAD2/3 in the regulation of epiregulin expression. In addition, miR-19a, -19b, and -20b are involved in post-transcriptional epiregulin regulation. The release of mature epiregulin occurs via proteolytic cleavage by ADAM17, MMP2, and MMP9 which are increased in castration-resistant prostate cancer cells. Discussion: The results demonstrate epiregulin regulation by different mechanism and suggest a potential role as a diagnostic tool to detect molecular alterations in prostate cancer progression. Additionally, although EGFR inhibitors false in prostate cancer, epiregulin could be a therapeutic target for patients with castration-resistant prostate cancer.

ESTRO-ACROP recommendations for evidence-based use of androgen deprivation therapy in combination with external-beam radiotherapy in prostate cancer.

BACKGROUND AND PURPOSE: There is no consensus concerning the appropriate use of androgen deprivation therapy (ADT) during primary and postoperative external-beam radiotherapy (EBRT) in the management of prostate cancer (PCa). Thus, the European Society for Radiotherapy and Oncology (ESTRO) Advisory Committee for Radiation Oncology Practice (ACROP) guidelines seeks to present current recommendations for the clinical use of ADT in the various indications of EBRT. MATERIAL AND METHODS: A literature search was conducted in MEDLINE PubMed that evaluated EBRT and ADT in prostate cancer. The search focused on randomized, Phase II and III trials published in English from January 2000 to May 2022. In case topics were addressed in the absence of Phase II or III trials, recommendations were labelled accordingly based on the limited body of evidence. Localized PCa was classified according to D'Amico et al. classification in low-, intermediate and high risk PCa. The ACROP clinical committee identified 13 European experts who discussed and analyzed the body of evidence concerning the use of ADT with EBRT for prostate cancer. RESULTS: Key issues were identified and are discussed: It was concluded that no additional ADT is recommended for low-risk prostate cancer patients, whereas for intermediate- and high-risk patients four to six months and two to three years of ADT are recommended. Likewise, patients with locally advanced prostate cancer are recommended to receive ADT for two to three years and when ≥ 2 high-risk factors (cT3-4, ISUP grade ≥ 4 or PSA ≥ 40 ng/ml) or cN1 is present ADT for three years plus additional Abiraterone for two years is recommended. For postoperative patients no ADT is recommended for adjuvant EBRT in pN0 patients whereas for pN1 patients adjuvant EBRT with long-term ADT is performed for at least 24 to 36 months. In the setting of salvage EBRT ADT is performed in biochemically persistent PCa patients with no evidence of metastatic disease. Long-term ADT (24 months) is recommended in pN0 patients with high risk of further progression (PSA ≥ 0.7 ng/ml and ISUP grade group ≥ 4) and a life expectancy of over ten years, whereas short-term ADT (6 months) is recommended in pN0 patients with lower risk profile (PSA < 0.7 ng/ml and ISUP grade group 4). Patients considered for ultra-hypofractionated EBRT as well as patients with image based local recurrence within the prostatic fossa or lymph node recurrence should participate in appropriate clinical trials evaluating the role of additional ADT. CONCLUSION: These ESTRO-ACROP recommendations are evidence-based and relevant to the use of ADT in combination with EBRT in PCa for the most common clinical settings.

Ki-67, topoisomerase IIα and miR-221 have a limited prostate cancer risk stratification ability on a medium-term follow-up: results of a high-risk radical prostatectomy cohort.

Background: Currently, no biomarkers are able to differentiate lethal from relatively indolent prostate cancer (PCa) within high-risk diseases. Nonetheless, several molecules are under investigation. Amongst them, topoisomerase-II-alpha (TOPIIA), Ki67 and miR-221 showed promising results. Our aim was to investigate their prognostic role in the context of biochemical recurrence (BCR), clinical recurrence (CR) and PCa-related death (PcD). Methods: We included 64 consecutive cM0 high-risk PCa [prostate specific antigen (PSA) >20 ng/mL or Gleason Score (GS) >7 or cT >2] undergoing radical prostatectomy (RP). Changes in miR-221 expression and alternative splicing were determined using microarrays. Immunohistochemical determination of Ki67 and TOPIIa were performed using monoclonal antibody MIB-1 and 3F6 respectively. Cox proportional-hazards regression models were used to predict BCR and CR as multivariate analysis. BCR and CR were defined as three consecutive rises in PSA and PSA >0.2 ng/mL and histologically-proven local recurrence or imaging positive for distant metastasis respectively. Results: We included 64 men. Mean pre-operative PSA was 26.53 (range, 1.3-135); all GSs were ≥7 and pT was ≥ T3 in 78.13%. Positive margins and lymph-nodes were present in 42.19% and 32.81% respectively. At a mean follow-up of 5.7 years (range, 1.8-12.5), 42.18% experienced BCR (n=27), 29.68% CR (n=19) and 7.81% PcD (n=5). On univariate analysis positive nodes (<0.01), seminal vesicle invasion (0.02) and miR-221 downregulation (P=0.03), but not Ki67 and TOPIIA (both P>0.5) were associated with BCR whereas only PSA (P<0.01), seminal vesicle invasion (P<0.01) and positive nodes (both P<0.01) were linked to CR. No parameters predicted PcD (all P>0.05) or BCR and CR on multivariate analysis (all P>0.05 - miR-221 HR 0.776; 95% CI: 0.503-1.196 for BCR and HR 0.673; 95% CI: 0.412-1.099 for CR). Limitation of the study include its small sample size and limited follow-up. Conclusions: TOPIIA, Ki-67 and miR-221 may not predict BCR, CR or PcD in high-risk PCa patients who underwent RP at a medium-term follow-up. Longer follow-up and larger cohorts are needed to confirm our findings.

Newly Diagnosed Oligometastatic Prostate Cancer: Current Controversies and Future Developments.

This report presents a 56-yr-old man in good general health status, newly diagnosed with a cT3b, cN1, cM1b, International Society of Urological Pathology grade group 3, low-volume (CHAARTED criteria), low-risk (LATITUDE criteria) metastatic prostate cancer. Staging was performed with conventional imaging: a computed tomography (CT) scan showed the presence of two enlarged lymph nodes on the left, close to the external iliac vessels. In addition, a suspicious 15-mm metastatic lesion was detected in the left pubic bone. This lesion was confirmed on the bone scan, without further metastatic lesions. In the context of a clinical trial, after an initial course of androgen deprivation therapy (ADT), the patient was treated with robot-assisted radical prostatectomy and extended pelvic lymph node dissection (histopathological examination: ypT3b pN1 R1). Postprostatectomy radiation therapy was delivered on prostatic bed (70Gy), pelvic lymph node area (54Gy), and pubic bone (51Gy). ADT was scheduled for a total period of 36 mo. Currently, the patient is still receiving ADT, which will be completed within 6 mo. The last prostate-specific antigen level was undetectable. The discussion is focused on the following three open questions: (1) Would molecular imaging (eg, prostate-specific membrane antigen positron emission tomography/CT) change the therapeutic approach to the patient? (2) Is there a role for local treatment in the metastatic setting? (iii) Should metastasis-directed therapy be considered for this patient? PATIENT SUMMARY: The optimal management of patients newly diagnosed with oligometastatic prostate cancer remains challenging. The fields of staging with modern imaging and therapy with novel treatment options are evolving rapidly. In particular, the role of a prostate-specific membrane antigen positron emission tomography/computed tomography scan for primary staging, the impact of a local treatment on the prostate, and the effect of direct therapies on the metastases represent important open questions in this intriguing field.

High expression of Sterol-O-Acyl transferase 1 (SOAT1), an enzyme involved in cholesterol metabolism, is associated with earlier biochemical recurrence in high risk prostate cancer.

BACKGROUND: Prostate cancer (PCa) is the most frequent cancer in men. The prognosis of PCa is heterogeneous with many clinically indolent tumors and rare highly aggressive cases. Reliable tissue markers of prognosis are lacking. Active cholesteryl ester synthesis has been associated with prostate cancer aggressiveness. Sterol-O-Acyl transferases (SOAT) 1 and 2 catalyze cholesterol esterification in humans. OBJECTIVE: To investigate the value of SOAT1 and SOAT2 tissue expression as prognostic markers in high risk PCa. PATIENTS AND METHODS: Formalin-fixed paraffin-embedded tissue samples from 305 high risk PCa cases treated with radical prostatectomy were analyzed for SOAT1 and SOAT2 protein expression by semi-quantitative immunohistochemistry. The Kaplan-Meier method and Cox proportional hazards modeling were used to compare outcome. MAIN OUTCOME MEASURE: Biochemical recurrence (BCR) free survival. RESULTS: SOAT1 expression was high in 73 (25%) and low in 219 (75%; not evaluable: 13) tumors. SOAT2 was highly expressed in 40 (14%) and at low levels in 249 (86%) samples (not evaluable: 16). By Kaplan-Meier analysis, we found significantly shorter median BCR free survival of 93 months (95% confidence interval 23.6-123.1) in patients with high SOAT1 vs. 134 months (112.6-220.2, Log-rank p < 0.001) with low SOAT1. SOAT2 expression was not significantly associated with BCR. After adjustment for age, preoperative PSA, tumor stage, Gleason score, resection status, lymph node involvement and year of surgery, high SOAT1 but not SOAT2 expression was associated with shorter BCR free survival with a hazard ratio of 2.40 (95% CI 1.57-3.68, p < 0.001). Time to clinical recurrence and overall survival were not significantly associated with SOAT1 and SOAT2 expression CONCLUSIONS: SOAT1 expression is strongly associated with BCR free survival alone and after multivariable adjustment in high risk PCa. SOAT1 may serve as a histologic marker of prognosis and holds promise as a future treatment target.

Dynamic prostate cancer transcriptome analysis delineates the trajectory to disease progression.

Comprehensive genomic studies have delineated key driver mutations linked to disease progression for most cancers. However, corresponding transcriptional changes remain largely elusive because of the bias associated with cross-study analysis. Here, we overcome these hurdles and generate a comprehensive prostate cancer transcriptome atlas that describes the roadmap to tumor progression in a qualitative and quantitative manner. Most cancers follow a uniform trajectory characterized by upregulation of polycomb-repressive-complex-2, G2-M checkpoints, and M2 macrophage polarization. Using patient-derived xenograft models, we functionally validate our observations and add single-cell resolution. Thereby, we show that tumor progression occurs through transcriptional adaption rather than a selection of pre-existing cancer cell clusters. Moreover, we determine at the single-cell level how inhibition of EZH2 - the top upregulated gene along the trajectory - reverts tumor progression and macrophage polarization. Finally, a user-friendly web-resource is provided enabling the investigation of dynamic transcriptional perturbations linked to disease progression.

Swiss germ-cell cancer consensus recommendations.

Approximately 420 men are diagnosed with germ-cell cancer (GCC) in Switzerland each year. Recent international guidelines outline management issues, but many aspects remain controversial in an area of highly individualised treatments. Even more than in other tumour types, in GCC the challenge is to choose exactly the correct treatment for an individual patient. Overtreatment in patients likely to be cured must be avoided to reduce long-term toxicities. On the other hand, treatment intensification is required in patients presenting with adverse prognostic factors. Therefore, referral to expert centres or consultations with an expert for a second opinion is strongly recommended. In 2020, Swiss experts discussed their strategies in a consensus meeting during the virtual Swiss Oncology and Haematology Congress (SOHC) in order to harmonise their concepts and to suggest optimal strategies for the management of GCC patients in Switzerland. Votes on controversial issues were obtained and are presented in this review wherever applicable.

Association of patients' sex with treatment outcomes after intravesical bacillus Calmette-Guérin immunotherapy for T1G3/HG bladder cancer.

PURPOSE: To investigate the association of patients' sex with recurrence and disease progression in patients treated with intravesical bacillus Calmette-Guérin (BCG) for T1G3/HG urinary bladder cancer (UBC). MATERIALS AND METHODS: We analyzed the data of 2635 patients treated with adjuvant intravesical BCG for T1 UBC between 1984 and 2019. We accounted for missing data using multiple imputations and adjusted for covariate imbalance between males and females using inverse probability weighting (IPW). Crude and IPW-adjusted Cox regression analyses were used to estimate the hazard ratios (HR) with their 95% confidence intervals (CI) for the association of patients' sex with HG-recurrence and disease progression. RESULTS: A total of 2170 (82%) males and 465 (18%) females were available for analysis. Overall, 1090 (50%) males and 244 (52%) females experienced recurrence, and 391 (18%) males and 104 (22%) females experienced disease progression. On IPW-adjusted Cox regression analyses, female sex was associated with disease progression (HR 1.25, 95%CI 1.01-1.56, p = 0.04) but not with recurrence (HR 1.06, 95%CI 0.92-1.22, p = 0.41). A total of 1056 patients were treated with adequate BCG. In these patients, on IPW-adjusted Cox regression analyses, patients' sex was not associated with recurrence (HR 0.99, 95%CI 0.80-1.24, p = 0.96), HG-recurrence (HR 1.00, 95%CI 0.78-1.29, p = 0.99) or disease progression (HR 1.12, 95%CI 0.78-1.60, p = 0.55). CONCLUSION: Our analysis generates the hypothesis of a differential response to BCG between males and females if not adequately treated. Further studies should focus on sex-based differences in innate and adaptive immune system and their association with BCG response.

Increased Expression of AKT3 in Neuroendocrine Differentiated Prostate Cancer Cells Alters the Response Towards Anti-Androgen Treatment.

Patients with advanced prostate carcinoma are often treated with an androgen deprivation therapy but long-term treatment can result in a metastatic castration-resistant prostate cancer. This is a more aggressive, untreatable tumor recurrence often containing areas of neuroendocrine differentiated prostate cancer cells. Using an in vitro model of NE-like cancer cells, it could previously be shown that neuroendocrine differentiation of LNCaP cells leads to a strong deregulation of mRNA and miRNA expression. We observe elevated RNA and protein levels of AKT Serine/Threonine Kinase 3 (AKT3) in neuroendocrine-like LNCaP cells. We used prostate resections from patients with neuroendocrine prostate cancer to validate these results and detect a co-localization of neuroendocrine marker genes with AKT3. Analysis of downstream target genes FOXO3A and GSK3 strengthens the assumption AKT3 may play a role in neuroendocrine differentiation. Overexpression of AKT3 shows an increased survival rate of LNCaP cells after apoptosis induction, which in turn reflects the significance in vivo or for treatment. Furthermore, miR-17, -20b and -106b, which are decreased in neuroendocrine-like LNCaP cells, negatively regulate AKT3 biosynthesis. Our findings demonstrate AKT3 as a potential therapeutic target and diagnostic tool in advanced neuroendocrine prostate cancer and a new mRNA-miRNA interaction with a potential role in neuroendocrine differentiation of prostate cancer.

Patient-derived xenografts and organoids model therapy response in prostate cancer.

Therapy resistance and metastatic processes in prostate cancer (PCa) remain undefined, due to lack of experimental models that mimic different disease stages. We describe an androgen-dependent PCa patient-derived xenograft (PDX) model from treatment-naïve, soft tissue metastasis (PNPCa). RNA and whole-exome sequencing of the PDX tissue and organoids confirmed transcriptomic and genomic similarity to primary tumor. PNPCa harbors BRCA2 and CHD1 somatic mutations, shows an SPOP/FOXA1-like transcriptomic signature and microsatellite instability, which occurs in 3% of advanced PCa and has never been modeled in vivo. Comparison of the treatment-naïve PNPCa with additional metastatic PDXs (BM18, LAPC9), in a medium-throughput organoid screen of FDA-approved compounds, revealed differential drug sensitivities. Multikinase inhibitors (ponatinib, sunitinib, sorafenib) were broadly effective on all PDX- and patient-derived organoids from advanced cases with acquired resistance to standard-of-care compounds. This proof-of-principle study may provide a preclinical tool to screen drug responses to standard-of-care and newly identified, repurposed compounds.

Small Molecular Inhibitors Block TRPM4 Currents in Prostate Cancer Cells, with Limited Impact on Cancer Hallmark Functions.

Transient receptor potential melastatin 4 (TRPM4) is a broadly expressed Ca2+ activated monovalent cation channel that contributes to the pathophysiology of several diseases. For this study, we generated stable CRISPR/Cas9 TRPM4 knockout (K.O.) cells from the human prostate cancer cell line DU145 and analyzed the cells for changes in cancer hallmark functions. Both TRPM4-K.O. clones demonstrated lower proliferation and viability compared to the parental cells. Migration was also impaired in the TRPM4-K.O. cells. Additionally, analysis of 210 prostate cancer patient tissues demonstrates a positive association between TRPM4 protein expression and local/metastatic progression. Moreover, a decreased adhesion rate was detected in the two K.O. clones compared to DU145 cells. Next, we tested three novel TRPM4 inhibitors with whole-cell patch clamp technique for their potential to block TRPM4 currents. CBA, NBA and LBA partially inhibited TRPM4 currents in DU145 cells. However, none of these inhibitors demonstrated any TRPM4-specific effect in the cellular assays. To evaluate if the observed effect of TRPM4 K.O. on migration, viability, and cell cycle is linked to TRPM4 ion conductivity, we transfected TRPM4-K.O. cells with either TRPM4 wild-type or a dominant-negative mutant, non-permeable to Na+. Our data showed a partial rescue of the viability of cells expressing functional TRPM4, while the pore mutant was not able to rescue this phenotype. For cell cycle distribution, TRPM4 ion conductivity was not essential since TRPM4 wild-type and the pore mutant rescued the phenotype. In conclusion, TRPM4 contributes to viability, migration, cell cycle shift, and adhesion; however, blocking TRPM4 ion conductivity is insufficient to prevent its role in cancer hallmark functions in prostate cancer cells.

Stroma Transcriptomic and Proteomic Profile of Prostate Cancer Metastasis Xenograft Models Reveals Prognostic Value of Stroma Signatures.

Resistance acquisition to androgen deprivation treatment and metastasis progression are a major clinical issue associated with prostate cancer (PCa). The role of stroma during disease progression is insufficiently defined. Using transcriptomic and proteomic analyses on differentially aggressive patient-derived xenografts (PDXs), we investigated whether PCa tumors predispose their microenvironment (stroma) to a metastatic gene expression pattern. RNA sequencing was performed on the PCa PDXs BM18 (castration-sensitive) and LAPC9 (castration-resistant), representing different disease stages. Using organism-specific reference databases, the human-specific transcriptome (tumor) was identified and separated from the mouse-specific transcriptome (stroma). To identify proteomic changes in the tumor (human) versus the stroma (mouse), we performed human/mouse cell separation and subjected protein lysates to quantitative Tandem Mass Tag labeling and mass spectrometry. Tenascin C (TNC) was among the most abundant stromal genes, modulated by androgen levels in vivo and highly expressed in castration-resistant LAPC9 PDX. The tissue microarray of primary PCa samples (n = 210) showed that TNC is a negative prognostic marker of the clinical progression to recurrence or metastasis. Stroma markers of osteoblastic PCa bone metastases seven-up signature were induced in the stroma by the host organism in metastatic xenografts, indicating conserved mechanisms of tumor cells to induce a stromal premetastatic signature. A 50-gene list stroma signature was identified based on androgen-dependent responses, which shows a linear association with the Gleason score, metastasis progression and progression-free survival. Our data show that metastatic PCa PDXs, which differ in androgen sensitivity, trigger differential stroma responses, which show the metastasis risk stratification and prognostic biomarker potential.

Role of specialized composition of SWI/SNF complexes in prostate cancer lineage plasticity.

Advanced prostate cancer initially responds to hormonal treatment, but ultimately becomes resistant and requires more potent therapies. One mechanism of resistance observed in around 10-20% of these patients is lineage plasticity, which manifests in a partial or complete small cell or neuroendocrine prostate cancer (NEPC) phenotype. Here, we investigate the role of the mammalian SWI/SNF (mSWI/SNF) chromatin remodeling complex in NEPC. Using large patient datasets, patient-derived organoids and cancer cell lines, we identify mSWI/SNF subunits that are deregulated in NEPC and demonstrate that SMARCA4 (BRG1) overexpression is associated with aggressive disease. We also show that SWI/SNF complexes interact with different lineage-specific factors in NEPC compared to prostate adenocarcinoma. These data point to a role for mSWI/SNF complexes in therapy-related lineage plasticity, which may also be relevant for other solid tumors.

miR-221-3p Regulates VEGFR2 Expression in High-Risk Prostate Cancer and Represents an Escape Mechanism from Sunitinib In Vitro.

Downregulation of miR-221-3p expression in prostate cancer (PCa) predicted overall and cancer-specific survival of high-risk PCa patients. Apart from PCa, miR-221-3p expression levels predicted a response to tyrosine kinase inhibitors (TKI) in clear cell renal cell carcinoma (ccRCC) patients. Since this role of miR-221-3p was explained with a specific targeting of VEGFR2, we examined whether miR-221-3p regulated VEGFR2 in PCa. First, we confirmed VEGFR2/KDR as a target gene of miR-221-3p in PCa cells by applying Luciferase reporter assays and Western blotting experiments. Although VEGFR2 was mainly downregulated in the PCa cohort of the TCGA (The Cancer Genome Atlas) database, VEGFR2 was upregulated in our high-risk PCa cohort (n = 142) and predicted clinical progression. In vitro miR-221-3p acted as an escape mechanism from TKI in PC3 cells, as displayed by proliferation and apoptosis assays. Moreover, we confirmed that Sunitinib induced an interferon-related gene signature in PC3 cells by analyzing external microarray data and by demonstrating a significant upregulation of miR-221-3p/miR-222-3p after Sunitinib exposure. Our findings bear a clinical perspective for high-risk PCa patients with low miR-221-3p levels since this could predict a favorable TKI response. Apart from this therapeutic niche, we identified a partially oncogenic function of miR-221-3p as an escape mechanism from VEGFR2 inhibition.

Preoperative Risk-Stratification of High-Risk Prostate Cancer: A Multicenter Analysis.

Background: Cancer-specific survival (CSS) within high-risk non-metastatic prostate cancer varies dramatically. It is likely that within this heterogenous population there are subgroup(s) at extraordinary risk, burdened with an exaptational poor prognosis. Establishing the characteristics of these group(s) would have significant clinical implications since high quality preoperative risk stratification remains the cornerstone of therapeutic decision making to date. Objective: To stratify high-risk prostate cancer based on preoperative characteristics and evaluate cancer specific survival after radical prostatectomy. Method: The EMPaCT multi-center database offers an international population of non-metastatic high-risk prostate cancer. Preoperative characteristics such as age, biopsy Gleason score, PSA and clinical stage were subcategorized. A multivariate analysis was performed using predictors showing significant survival heterogeneity after stratification, as observed by a univariate analysis. Based upon the hazard ratios of this multivariate analysis, a proportional score system was created. The most ideal group distribution was evaluated trough different score cut-off's. The predictive value was tested by the herald C index. Results: An overall 5-years CSS of 94% was noted within the entire high-risk cohort (n = 4,879). Except for age, all preoperative risk factors showed a significantly differing CSS. Multivariate analysis indicated, T4 stage as being the strongest predictor of CSS (HR: 3.31), followed by ISUP grade 5 group (HR 3,05). A score system was created by doubling the hazard ratios of this multivariate analysis and rounding off to the nearest complete number. Multivariate analysis suggested 0, 4, 8, and 12 pts as being the most optimal group distribution (p-value: 0.0015). Five-years CSS of these groups were 97, 93, 87, and 70%, respectively. The calculated Herald C-index of the model was 0.77. Conclusion: An easy-to-use pre-operative model for risk stratification of newly diagnosed high-risk prostate cancer is presented. The heterogeneous CSS of high-risk non-metastatic prostate cancer after radical prostatectomy is illustrated. The model is clinically accessible through an online calculator, presenting cancer specific survival based on individualized patient characteristics.