Defining the challenges and opportunities for using patient-derived models in prostate cancer research.

BACKGROUND: There are relatively few widely used models of prostate cancer compared to other common malignancies. This impedes translational prostate cancer research because the range of models does not reflect the diversity of disease seen in clinical practice. In response to this challenge, research laboratories around the world have been developing new patient-derived models of prostate cancer, including xenografts, organoids, and tumor explants. METHODS: In May 2023, we held a workshop at the Monash University Prato Campus for researchers with expertise in establishing and using a variety of patient-derived models of prostate cancer. This review summarizes our collective ideas on how patient-derived models are currently being used, the common challenges, and future opportunities for maximizing their usefulness in prostate cancer research. RESULTS: An increasing number of patient-derived models for prostate cancer are being developed. Despite their individual limitations and varying success rates, these models are valuable resources for exploring new concepts in prostate cancer biology and for preclinical testing of potential treatments. Here we focus on the need for larger collections of models that represent the changing treatment landscape of prostate cancer, robust readouts for preclinical testing, improved in vitro culture conditions, and integration of the tumor microenvironment. Additional priorities include ensuring model reproducibility, standardization, and replication, and streamlining the exchange of models and data sets among research groups. CONCLUSIONS: There are several opportunities to maximize the impact of patient-derived models on prostate cancer research. We must develop large, diverse and accessible cohorts of models and more sophisticated methods for emulating the intricacy of patient tumors. In this way, we can use the samples that are generously donated by patients to advance the outcomes of patients in the future.

Altered expression of vesicular trafficking machinery in prostate cancer affects lysosomal dynamics and provides insight into the underlying biology and disease progression.

BACKGROUND: This study focuses on the role of lysosomal trafficking in prostate cancer, given the essential role of lysosomes in cellular homoeostasis. METHODS: Lysosomal motility was evaluated using confocal laser scanning microscopy of LAMP-1-transfected prostate cells and spot-tracking analysis. Expression of lysosomal trafficking machinery was evaluated in patient cohort databases and through immunohistochemistry on tumour samples. The roles of vesicular trafficking machinery were evaluated through over-expression and siRNA. The effects of R1881 treatment on lysosome vesicular trafficking was evaluated by RNA sequencing, protein quantification and fixed- and live-cell microscopy. RESULTS: Altered regulation of lysosomal trafficking genes/proteins was observed in prostate cancer tissue, with significant correlations for co-expression of vesicular trafficking machinery in Gleason patterns. The expression of trafficking machinery was associated with poorer patient outcomes. R1881 treatment induced changes in lysosomal distribution, number, and expression of lysosomal vesicular trafficking machinery in hormone-sensitive prostate cancer cells. Manipulation of genes involved in lysosomal trafficking events induced changes in lysosome positioning and cell phenotype, as well as differential effects on cell migration, in non-malignant and prostate cancer cells. CONCLUSIONS: These findings provide novel insights into the altered regulation and functional impact of lysosomal vesicular trafficking in prostate cancer pathogenesis.

Peroxisomal ß-oxidation enzyme, DECR2, regulates lipid metabolism and promotes treatment resistance in advanced prostate cancer.

BACKGROUND: Peroxisomes are central metabolic organelles that have key roles in fatty acid homoeostasis. As prostate cancer (PCa) is particularly reliant on fatty acid metabolism, we explored the contribution of peroxisomal ß-oxidation (perFAO) to PCa viability and therapy response. METHODS: Bioinformatic analysis was performed on clinical transcriptomic datasets to identify the perFAO enzyme, 2,4-dienoyl CoA reductase 2 (DECR2) as a target gene of interest. Impact of DECR2 and perFAO inhibition via thioridazine was examined in vitro, in vivo, and in clinical prostate tumours cultured ex vivo. Transcriptomic and lipidomic profiling was used to determine the functional consequences of DECR2 inhibition in PCa. RESULTS: DECR2 is upregulated in clinical PCa, most notably in metastatic castrate-resistant PCa (CRPC). Depletion of DECR2 significantly suppressed proliferation, migration, and 3D growth of a range of CRPC and therapy-resistant PCa cell lines, and inhibited LNCaP tumour growth and proliferation in vivo. DECR2 influences cell cycle progression and lipid metabolism to support tumour cell proliferation. Further, co-targeting of perFAO and standard-of-care androgen receptor inhibition enhanced suppression of PCa cell proliferation. CONCLUSION: Our findings support a focus on perFAO, specifically DECR2, as a promising therapeutic target for CRPC and as a novel strategy to overcome lethal treatment resistance.

CDK9 inhibition inhibits multiple oncogenic transcriptional and epigenetic pathways in prostate cancer.

BACKGROUND: Cyclin-dependent kinase 9 (CDK9) stimulates oncogenic transcriptional pathways in cancer and CDK9 inhibitors have emerged as promising therapeutic candidates. METHODS: The activity of an orally bioavailable CDK9 inhibitor, CDKI-73, was evaluated in prostate cancer cell lines, a xenograft mouse model, and patient-derived tumor explants and organoids. Expression of CDK9 was evaluated in clinical specimens by mining public datasets and immunohistochemistry. Effects of CDKI-73 on prostate cancer cells were determined by cell-based assays, molecular profiling and transcriptomic/epigenomic approaches. RESULTS: CDKI-73 inhibited proliferation and enhanced cell death in diverse in vitro and in vivo models of androgen receptor (AR)-driven and AR-independent models. Mechanistically, CDKI-73-mediated inhibition of RNA polymerase II serine 2 phosphorylation resulted in reduced expression of BCL-2 anti-apoptotic factors and transcriptional defects. Transcriptomic and epigenomic approaches revealed that CDKI-73 suppressed signaling pathways regulated by AR, MYC, and BRD4, key drivers of dysregulated transcription in prostate cancer, and reprogrammed cancer-associated super-enhancers. These latter findings prompted the evaluation of CDKI-73 with the BRD4 inhibitor AZD5153, a combination that was synergistic in patient-derived organoids and in vivo. CONCLUSION: Our work demonstrates that CDK9 inhibition disrupts multiple oncogenic pathways and positions CDKI-73 as a promising therapeutic agent for prostate cancer, particularly aggressive, therapy-resistant subtypes.

Fatty acid elongation regulates mitochondrial ß-oxidation and cell viability in prostate cancer by controlling malonyl-CoA levels.

Recently, the fatty acid elongation enzyme ELOVL5 was identified as a critical pro-metastatic factor in prostate cancer, required for cell growth and mitochondrial homeostasis. The fatty acid elongation reaction catalyzed by ELOVL5 utilizes malonyl-CoA as the carbon donor. Here, we demonstrate that ELOVL5 knockdown causes malonyl-CoA accumulation. Malonyl-CoA is a cellular substrate that can inhibit fatty acid ß-oxidation in the mitochondria through allosteric inhibition of carnitine palmitoyltransferase 1A (CPT1A), the enzyme that controls the rate-limiting step of the long chain fatty acid ß-oxidation cycle. We hypothesized that changes in malonyl-CoA abundance following ELOVL5 knockdown could influence mitochondrial ß-oxidation rates in prostate cancer cells, and regulate cell viability. Accordingly, we find that ELOVL5 knockdown is associated with decreased mitochondrial ß-oxidation in prostate cancer cells. Combining ELOVL5 knockdown with FASN inhibition to increase malonyl-CoA abundance endogenously enhances the effect of ELOVL5 knockdown on prostate cancer cell viability, while preventing malonyl-CoA production rescues the cells from the effect of ELOVL5 knockdown. Our findings indicate an additional role for fatty acid elongation, in the control of malonyl-CoA homeostasis, alongside its established role in the production of long-chain fatty acid species, to explain the importance of fatty acid elongation for cell viability.

Spatial MS multiomics on clinical prostate cancer tissues.

Mass spectrometry (MS) and MS imaging (MSI) are used extensively for both the spatial and bulk characterization of samples in lipidomics and proteomics workflows. These datasets are typically generated independently due to different requirements for sample preparation. However, modern omics technologies now provide higher sample throughput and deeper molecular coverage, which, in combination with more sophisticated bioinformatic and statistical pipelines, make generating multiomics data from a single sample a reality. In this workflow, we use spatial lipidomics data generated by matrix-assisted laser desorption/ionization MSI (MALDI-MSI) on prostate cancer (PCa) radical prostatectomy cores to guide the definition of tumor and benign tissue regions for laser capture microdissection (LCM) and bottom-up proteomics all on the same sample and using the same mass spectrometer. Accurate region of interest (ROI) mapping was facilitated by the SCiLS region mapper software and dissected regions were analyzed using a dia-PASEF workflow. A total of 5525 unique protein groups were identified from all dissected regions. Lysophosphatidylcholine acyltransferase 1 (LPCAT1), a lipid remodelling enzyme, was significantly enriched in the dissected regions of cancerous epithelium (CE) compared to benign epithelium (BE). The increased abundance of this protein was reflected in the lipidomics data with an increased ion intensity ratio for pairs of phosphatidylcholines (PC) and lysophosphatidylcholines (LPC) in CE compared to BE.

Food insecurity and unemployment as mediators of the relationship between the COVID-19 pandemic and psychological well-being in young South Africans with HIV.

BACKGROUND: Poor psychological well-being, including depression, anxiety, and low self-esteem, is both prevalent among young South Africans living with HIV and associated with poor HIV clinical outcomes. By impacting food insecurity and employment, the COVID-19 pandemic may have influenced psychological well-being in this population. This analysis sought to examine whether food insecurity and unemployment mediated the relationship between study cohort (pre- versus during-pandemic) and psychological well-being in our sample of young South Africans living with HIV. METHODS: This was a secondary analysis comparing baseline data from two cohorts of young South Africans ages 18-24 from the Cape Town and East London metro areas who tested positive for HIV at clinics (or mobile clinics) either before or during the COVID-19 pandemic. Baseline sociodemographic, economic, and psychological outcomes were analyzed through a series of bivariate logistic regression and mediation analyses. All data were analyzed in 2023 and 2024. RESULTS: Reported food anxiety, insufficient food quality, and insufficient food quantity were lower in the cohort recruited during the COVID-19 pandemic than those recruited before the pandemic (p < 0.001). Higher levels of food insecurity predicted higher depressive and anxiety symptoms and lower self-esteem. Food anxiety, insufficient food quality, and insufficient food quantity, but not unemployment, mediated the relationship between study cohort and depressive symptoms, anxiety symptoms, and self-esteem. CONCLUSION: Food insecurity may have decreased amongst our sample of young people during the COVID-19 pandemic. Our findings build on our understanding of how the psychological well-being of young people living with HIV was affected by the COVID-19 pandemic and may lend support to interventions targeting food insecurity to improve psychological well-being in this population.

Disclosure Events and Psychosocial Well-Being Among Young South African Adults Living with HIV.

BACKGROUND: Poor psychological well-being is both prevalent among South Africans living with HIV and has been associated with poor HIV clinical outcomes. However, the relationship between disclosure and psychological well-being remains unclear. This analysis sought to examine the relationship between two disclosure-related variables, disclosure status and reaction received, and psychosocial well-being among a sample of young adults living with HIV (YALWH) in urban South Africa. METHOD: This was a secondary analysis using observational data from Standing Tall, a randomized controlled trial that recruited 100 participants ages 18-24 who tested positive for HIV after initially presenting to two well-established mobile clinics for HIV testing. Interviews investigating primary and secondary outcomes of interest were done at baseline and 6 months following recruitment. RESULTS: About half (51%) of participants disclosed their HIV status within 6 months after recruitment. Simple linear regression analyses revealed that disclosure of HIV status within 6 months after study enrollment predicted significantly lower levels of disclosure concerns and internalized stigma (p < 0.05). Reactions to disclosure were not significantly associated with any of the measures of psychosocial well-being considered in this analysis (p > 0.05). CONCLUSION: The results suggest that the act of disclosure among newly diagnosed YALWH may be associated with reductions in internalized stigma. In addition, the finding that the act of disclosure may be a more important determinant of psychosocial well-being than the reaction to disclosure has important implications for interventions designed to promote disclosure and psychosocial well-being in YALWH.

Targeting hyaluronan-mediated motility receptor (HMMR) enhances response to androgen receptor signalling inhibitors in prostate cancer.

BACKGROUND: Resistance to androgen receptor signalling inhibitors (ARSIs) represents a major clinical challenge in prostate cancer. We previously demonstrated that the ARSI enzalutamide inhibits only a subset of all AR-regulated genes, and hypothesise that the unaffected gene networks represent potential targets for therapeutic intervention. This study identified the hyaluronan-mediated motility receptor (HMMR) as a survival factor in prostate cancer and investigated its potential as a co-target for overcoming resistance to ARSIs. METHODS: RNA-seq, RT-qPCR and Western Blot were used to evaluate the regulation of HMMR by AR and ARSIs. HMMR inhibition was achieved via siRNA knockdown or pharmacological inhibition using 4-methylumbelliferone (4-MU) in prostate cancer cell lines, a mouse xenograft model and patient-derived explants (PDEs). RESULTS: HMMR was an AR-regulated factor that was unaffected by ARSIs. Genetic (siRNA) or pharmacological (4-MU) inhibition of HMMR significantly suppressed growth and induced apoptosis in hormone-sensitive and enzalutamide-resistant models of prostate cancer. Mechanistically, 4-MU inhibited AR nuclear translocation, AR protein expression and subsequent downstream AR signalling. 4-MU enhanced the growth-suppressive effects of 3 different ARSIs in vitro and, in combination with enzalutamide, restricted proliferation of prostate cancer cells in vivo and in PDEs. CONCLUSION: Co-targeting HMMR and AR represents an effective strategy for improving response to ARSIs.

The Origin and Contribution of Cancer-Associated Fibroblasts in Colorectal Carcinogenesis.

BACKGROUND & AIMS: Cancer-associated fibroblasts (CAFs) play an important role in colorectal cancer (CRC) progression and predict poor prognosis in CRC patients. However, the cellular origins of CAFs remain unknown, making it challenging to therapeutically target these cells. Here, we aimed to identify the origins and contribution of colorectal CAFs associated with poor prognosis. METHODS: To elucidate CAF origins, we used a colitis-associated CRC mouse model in 5 different fate-mapping mouse lines with 5-bromodeoxyuridine dosing. RNA sequencing of fluorescence-activated cell sorting-purified CRC CAFs was performed to identify a potential therapeutic target in CAFs. To examine the prognostic significance of the stromal target, CRC patient RNA sequencing data and tissue microarray were used. CRC organoids were injected into the colons of knockout mice to assess the mechanism by which the stromal gene contributes to colorectal tumorigenesis. RESULTS: Our lineage-tracing studies revealed that in CRC, many ACTA2+ CAFs emerge through proliferation from intestinal pericryptal leptin receptor (Lepr)+ cells. These Lepr-lineage CAFs, in turn, express melanoma cell adhesion molecule (MCAM), a CRC stroma-specific marker that we identified with the use of RNA sequencing. High MCAM expression induced by transforming growth factor ß was inversely associated with patient survival in human CRC. In mice, stromal Mcam knockout attenuated orthotopically injected colorectal tumoroid growth and improved survival through decreased tumor-associated macrophage recruitment. Mechanistically, fibroblast MCAM interacted with interleukin-1 receptor 1 to augment nuclear factor κB-IL34/CCL8 signaling that promotes macrophage chemotaxis. CONCLUSIONS: In colorectal carcinogenesis, pericryptal Lepr-lineage cells proliferate to generate MCAM+ CAFs that shape the tumor-promoting immune microenvironment. Preventing the expansion/differentiation of Lepr-lineage CAFs or inhibiting MCAM activity could be effective therapeutic approaches for CRC.

Relationship Power, Antiretroviral Adherence, and Physical and Mental Health Among Women Living with HIV in Rural Kenya.

Little is known about the association of gender-based power imbalances and health and health behaviors among women with HIV (WWH). We examined cross-sectional baseline data among WWH in a cluster-randomized control trial (NCT02815579) in rural Kenya. We assessed associations between the Sexual Relationship Power Scale (SRPS) and ART adherence, physical and mental health, adjusting for sociodemographic and social factors. SRPS consists of two subscales: relationship control (RC) and decision-making dominance. Women in the highest and middle tertiles for RC had a 7.49 point and 8.88 point greater Medical Outcomes Study-HIV mental health score, and a 0.27 and 0.29 lower odds of depression, respectively, compared to women in the lowest tertile. We did not find associations between SPRS or its subscales and ART adherence. Low sexual relationship power, specifically low RC, may be associated with poor mental health among WWH. Intervention studies aimed to improve RC among WWH should be studied to determine their effect on improving mental health.

RESUMEN: Poco se sabe acerca de su asociación con los desequilibrios de poder basados en el género y los comportamientos de salud y salud entre las mujeres con Virus de Inmunodeficiencia Humana (VIH). Examinamos los datos de referencia transversales entre mujeres con VIH en un ensayo de control aleatorizado por grupos (NCT02815579) en las zonas rurales de Kenia. Evaluamos las asociaciones entre la Escala de Poder de Relación Sexual y la adherencia a la Terapia Antirretroviral (TAR), la salud física y mental, ajustando por factores sociodemográficos y sociales. La Escala de Poder de Relación Sexual consiste de dos subescalas: control de relaciones y dominio en la toma de decisiones. Las mujeres en los terciles más alto y mediano para control de relaciones tenían una puntuación de salud mental de 7.49 puntos y 8.88 puntos mayor en el Medical Outcomes Study HIV Health Survey (MOS)-HIV, y una puntuación de salud mental de 0.27 y 0.29 menores probabilidades de depresión, respectivamente, en comparación con las mujeres en el tercil más bajo. El bajo poder de relación sexual, específicamente el control de relaciones bajo, puede estar asociado con una salud mental deficiente entre las mujeres con VIH. Se deben estudiar estudios de intervención destinados a mejorar el control de relaciones entre mujeres con VIH para determinar su efecto en mejorar la salud mental.

Incidence of HIV disclosure among HIV affected heterosexual partners using a community health worker led mechanism in rural Uganda; a quasi-experimental study.

BACKGROUND: HIV disclosure is vital in HIV management. Community Health Workers (CHW) were reported to support partner disclosure among HIV affected heterosexual partners with disclosure difficulties. However, time to disclosure attributed to use of CHW led disclosure support mechanism was not documented. This study compared the incidence of sexual partner disclosure among adults living with HIV (ALHIV) with CHW support and those without in the greater Luwero region, Uganda. METHODS: We conducted a quasi-experimental study with two arms allocated by geographically determined clusters and adjusted for between-group differences; among ALHIV in the greater Luwero region of Uganda who had never disclosed to their current primary sexual partners. We allocated study clusters to either a CHW-led intervention or control arm. In both arms, we consecutively recruited participants; those in the intervention arm received CHW disclosure support in addition to routine care. The overall follow-up was six months, and the primary outcome was disclosure to the partner. We used survival analysis with proportional hazard ratios to determine the time to partner disclosure in both arms. RESULTS: A total of 245 participants were enrolled, and 230 (93.9%) completed the study; of these, 112 (48.7%) were in the intervention and 118 (51.3%) in the control arm. The mean age was 31 ± 8 years with a range of 18 to 55 years; the majority were females, 176 (76.5%). The cumulative incidence of disclosure was higher in the intervention arm, 8.76 [95% CI: 7.20-10.67] per 1,000 person-days versus 5.15 [95%CI: 4.85-6.48] per 1,000 person-days in the control arm, log-rank test, X2 = 12.93, P < 0.001. Male gender, aHR = 1.82, tertiary education, aHR = 1.51, and relationship duration of > six months, aHR = 1.19 predicted disclosure. Prior disclosure to a relative, aHR = 0.55, and having more than one sexual partner in the past three months, aHR = 0.74, predicted non-disclosure. CONCLUSION: CHW-led support mechanism increased the rate of sexual partner disclosure among ALHIV with disclosure difficulties. Therefore, to achieve the global targets of ending HIV, near location CHW-led disclosure support mechanism may be used to hasten HIV disclosure in rural settings.

Experiences and challenges of using community health worker-led mechanism in supporting HIV disclosure among adults living with HIV in heterosexual relationships in the rural Uganda.

BACKGROUND: HIV status disclosure among sexual partners is vital in HIV management. Community health workers (CHW) support HIV disclosure among adults living with HIV (ALHIV) in sexual relationships with disclosure difficulties. However, experiences and challenges of using CHW-led disclosure support mechanism were not documented. This study explored experiences and challenges involved in using CHW-led disclosure support mechanism among ALHIV in heterosexual relationships in the rural Uganda. METHODS: This was a phenomenological qualitative study involving in-depth interviews among CHWs and ALHIV with HIV disclosure difficulties to sexual partners in greater Luwero region, Uganda. We conducted 27 interviews among purposively selected CHWs and participants who had participated in the CHW-led disclosure support mechanism. Interviews were conducted until saturation was reached; and analysis was done using inductive and deductive content analysis in Atlas. RESULTS: All respondents viewed HIV disclosure as an important strategy in HIV management. Provision of adequate counseling and support to those intending to disclose was instrumental for successful disclosure. However, fear of the negative disclosure outcomes was viewed as a barrier to disclosure. The CHWs were viewed as having an added advantage in supporting disclosure as opposed to the routine disclosure counseling. However, HIV disclosure using CHW-led support mechanism would be limited by possible bleach of client's confidentiality. Therefore, respondents thought that appropriate selection of CHWs would improve their trust in the community. Additionally, providing CHWs with adequate training and facilitation during the disclosure support mechanism was viewed to improve their work. CONCLUSION: Community health workers were viewed as being more supportive in HIV disclosure among ALHIV with disclosure difficulties to sexual partners compared to routine facility based disclosure counseling. Therefore, near location CHW-led disclosure mechanism was acceptable and useful in supporting HIV disclosure among HIV-affected sexual partners in rural settings.

The Balance of Stromal BMP Signaling Mediated by GREM1 and ISLR Drives Colorectal Carcinogenesis.

BACKGROUND & AIMS: Cancer-associated fibroblasts (CAFs), key constituents of the tumor microenvironment, either promote or restrain tumor growth. Attempts to therapeutically target CAFs have been hampered by our incomplete understanding of these functionally heterogeneous cells. Key growth factors in the intestinal epithelial niche, bone morphogenetic proteins (BMPs), also play a critical role in colorectal cancer (CRC) progression. However, the crucial proteins regulating stromal BMP balance and the potential application of BMP signaling to manage CRC remain largely unexplored. METHODS: Using human CRC RNA expression data, we identified CAF-specific factors involved in BMP signaling, then verified and characterized their expression in the CRC stroma by in situ hybridization. CRC tumoroids and a mouse model of CRC hepatic metastasis were used to test approaches to modify BMP signaling and treat CRC. RESULTS: We identified Grem1 and Islr as CAF-specific genes involved in BMP signaling. Functionally, GREM1 and ISLR acted to inhibit and promote BMP signaling, respectively. Grem1 and Islr marked distinct fibroblast subpopulations and were differentially regulated by transforming growth factor ß and FOXL1, providing an underlying mechanism to explain fibroblast biological dichotomy. In patients with CRC, high GREM1 and ISLR expression levels were associated with poor and favorable survival, respectively. A GREM1-neutralizing antibody or fibroblast Islr overexpression reduced CRC tumoroid growth and promoted Lgr5+ intestinal stem cell differentiation. Finally, adeno-associated virus 8 (AAV8)-mediated delivery of Islr to hepatocytes increased BMP signaling and improved survival in our mouse model of hepatic metastasis. CONCLUSIONS: Stromal BMP signaling predicts and modifies CRC progression and survival, and it can be therapeutically targeted by novel AAV-directed gene delivery to the liver.

Combined impact of lipidomic and genetic aberrations on clinical outcomes in metastatic castration-resistant prostate cancer.

BACKGROUND: Both changes in circulating lipids represented by a validated poor prognostic 3-lipid signature (3LS) and somatic tumour genetic aberrations are individually associated with worse clinical outcomes in men with metastatic castration-resistant prostate cancer (mCRPC). A key question is how the lipid environment and the cancer genome are interrelated in order to exploit this therapeutically. We assessed the association between the poor prognostic 3-lipid signature (3LS), somatic genetic aberrations and clinical outcomes in mCRPC. METHODS: We performed plasma lipidomic analysis and cell-free DNA (cfDNA) sequencing on 106 men with mCRPC commencing docetaxel, cabazitaxel, abiraterone or enzalutamide (discovery cohort) and 94 men with mCRPC commencing docetaxel (validation cohort). Differences in lipid levels between men ± somatic genetic aberrations were assessed with t-tests. Associations between the 3LS and genetic aberrations with overall survival (OS) were examined using Kaplan-Meier methods and Cox proportional hazard models. RESULTS: The 3LS was associated with shorter OS in the discovery (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.4-3.3, p < 0.001) and validation cohorts (HR 2.32, 95% CI 1.59-3.38, p < 0.001). Elevated plasma sphingolipids were associated with AR, TP53, RB1 and PI3K aberrations (p < 0.05). Men with both the 3LS and aberrations in AR, TP53, RB1 or PI3K had shorter OS than men with neither in both cohorts (p ≤ 0.001). The presence of 3LS and/or genetic aberration was independently associated with shorter OS for men with AR, TP53, RB1 and PI3K aberrations (p < 0.02). Furthermore, aggressive-variant prostate cancer (AVPC), defined as 2 or more aberrations in TP53, RB1 and/or PTEN, was associated with elevated sphingolipids. The combination of AVPC and 3LS predicted for a median survival of ~12 months. The relatively small sample size of the cohorts limits clinical applicability and warrants future studies. CONCLUSIONS: Elevated circulating sphingolipids were associated with AR, TP53, RB1, PI3K and AVPC aberrations in mCRPC, and the combination of lipid and genetic abnormalities conferred a worse prognosis. These findings suggest that certain genotypes in mCRPC may benefit from metabolic therapies.

Prostate cancer cell-intrinsic interferon signaling regulates dormancy and metastatic outgrowth in bone.

The latency associated with bone metastasis emergence in castrate-resistant prostate cancer is attributed to dormancy, a state in which cancer cells persist prior to overt lesion formation. Using single-cell transcriptomics and ex vivo profiling, we have uncovered the critical role of tumor-intrinsic immune signaling in the retention of cancer cell dormancy. We demonstrate that loss of tumor-intrinsic type I IFN occurs in proliferating prostate cancer cells in bone. This loss suppresses tumor immunogenicity and therapeutic response and promotes bone cell activation to drive cancer progression. Restoration of tumor-intrinsic IFN signaling by HDAC inhibition increased tumor cell visibility, promoted long-term antitumor immunity, and blocked cancer growth in bone. Key findings were validated in patients, including loss of tumor-intrinsic IFN signaling and immunogenicity in bone metastases compared to primary tumors. Data herein provide a rationale as to why current immunotherapeutics fail in bone-metastatic prostate cancer, and provide a new therapeutic strategy to overcome the inefficacy of immune-based therapies in solid cancers.

Water Insecurity is Associated with Lack of Viral Suppression and Greater Odds of AIDS-Defining Illnesses Among Adults with HIV in Western Kenya.

Reliable access to safe and acceptable water in sufficient quantities (i.e., water security) is important for medication adherence and limiting pathogen exposure, yet prior studies have only considered the role of food security as a social determinant of HIV-related health. Therefore, the objective of this analysis was to assess the relationships between household water insecurity and HIV-related outcomes among adults living with HIV in western Kenya (N = 716). We conducted a cross-sectional analysis of baseline data from Shamba Maisha (NCT02815579), a cluster randomized controlled trial of a multisectoral agricultural and asset loan intervention. Baseline data were collected from June 2016 to December 2017. We assessed associations between water insecurity and HIV-related outcomes, adjusting for clinical and behavioral confounders, including food insecurity. Each five-unit higher household water insecurity score (range: 0-51) was associated with 1.21 higher odds of having a viral load ≥ 1000 copies/mL (95% CI 1.07, 1.36) and 1.26 higher odds of AIDS-defining illness (95% CI 1.11, 1.42). Household water insecurity was not associated with CD4 cell count (B: 0.27; 95% CI -3.59, 13.05). HIV treatment and support programs should consider assessing and addressing water insecurity in addition to food insecurity to optimize HIV outcomes.

RESUMEN: El acceso seguro al agua potable en cantidades suficientes (es decir, seguridad hídrica) es importante para la adherencia a la medicación y para limitar la exposición a patógenos; sin embargo, estudios anteriores solo han considerado el papel de la seguridad alimentaria como un determinante social de salud relacionado con el VIH. Por lo tanto, el objetivo de este análisis fue evaluar las relaciones entre la inseguridad hídrica en hogares y los resultados relacionados con el VIH en adultos que viven con VIH en el oeste de Kenia (N = 716). Realizamos un análisis transversal de los datos basales de la iniciativa Shamba Maisha (NCT02815579), un ensayo controlado aleatorio por conglomerados de una intervención multisectorial de créditos para insumos agrícolas. Los datos basales se recopilaron de junio de 2016 a diciembre de 2017. Evaluamos las asociaciones entre la inseguridad hídrica y resultados relacionados con el VIH, ajustando por factores de confusión clínicos y conductuales, incluyendo inseguridad alimentaria. Cada cinco unidades superiores de puntajes de inseguridad hídrica doméstica (rango: 0-51) fue asociado con 1.21 mayores probabilidades de tener una carga viral más alta ≥ 1000 copias / ml (CI 95%: 1,07-1,36) y con 1.26 mayores probabilidades de factores determinantes del SIDA (CI 95%: 1,11-1,42). La inseguridad de hídrica doméstica no se asoció con el recuento de células CD4 (B: −0,27; CI 95%: -13,59-13,05). Los programas de tratamiento y de apoyo al VIH deben considerar evaluar y abordar la inseguridad hídrica además de la inseguridad alimentaria para optimizar los resultados del VIH.

Reciprocal signaling between mTORC1 and MNK2 controls cell growth and oncogenesis.

eIF4E plays key roles in protein synthesis and tumorigenesis. It is phosphorylated by the kinases MNK1 and MNK2. Binding of MNKs to eIF4G enhances their ability to phosphorylate eIF4E. Here, we show that mTORC1, a key regulator of mRNA translation and oncogenesis, directly phosphorylates MNK2 on Ser74. This suppresses MNK2 activity and impairs binding of MNK2 to eIF4G. These effects provide a novel mechanism by which mTORC1 signaling impairs the function of MNK2 and thereby decreases eIF4E phosphorylation. MNK2[S74A] knock-in cells show enhanced phosphorylation of eIF4E and S6K1 (i.e., increased mTORC1 signaling), enlarged cell size, and increased invasive and transformative capacities. MNK2[Ser74] phosphorylation was inversely correlated with disease progression in human prostate tumors. MNK inhibition exerted anti-proliferative effects in prostate cancer cells in vitro. These findings define a novel feedback loop whereby mTORC1 represses MNK2 activity and oncogenic signaling through eIF4E phosphorylation, allowing reciprocal regulation of these two oncogenic pathways.

Inhibition of de novo lipogenesis targets androgen receptor signaling in castration-resistant prostate cancer.

A hallmark of prostate cancer progression is dysregulation of lipid metabolism via overexpression of fatty acid synthase (FASN), a key enzyme in de novo fatty acid synthesis. Metastatic castration-resistant prostate cancer (mCRPC) develops resistance to inhibitors of androgen receptor (AR) signaling through a variety of mechanisms, including the emergence of the constitutively active AR variant V7 (AR-V7). Here, we developed an FASN inhibitor (IPI-9119) and demonstrated that selective FASN inhibition antagonizes CRPC growth through metabolic reprogramming and results in reduced protein expression and transcriptional activity of both full-length AR (AR-FL) and AR-V7. Activation of the reticulum endoplasmic stress response resulting in reduced protein synthesis was involved in IPI-9119-mediated inhibition of the AR pathway. In vivo, IPI-9119 reduced growth of AR-V7-driven CRPC xenografts and human mCRPC-derived organoids and enhanced the efficacy of enzalutamide in CRPC cells. In human mCRPC, both FASN and AR-FL were detected in 87% of metastases. AR-V7 was found in 39% of bone metastases and consistently coexpressed with FASN. In patients treated with enzalutamide and/or abiraterone FASN/AR-V7 double-positive metastases were found in 77% of cases. These findings provide a compelling rationale for the use of FASN inhibitors in mCRPCs, including those overexpressing AR-V7.

"You are not alone": a qualitative study to explore barriers to ART initiation and implications for a proposed community-based youth treatment club among young adults newly diagnosed with HIV in South Africa.

In South Africa, despite universal antiretroviral therapy (ART) availability, 60% of persons living with HIV (PLWH) ages 15-24 are not on treatment. This qualitative study aimed to identify barriers to ART initiation and the implications for a proposed community-based Youth Treatment Club to improve ART initiation for young PLWH in limited-resource, high HIV-prevalence communities in Cape Town, South Africa. Recruiting participants at community testing sites from 2018 to 2019, we conducted semi-structured interviews, informed by Social Action Theory (SAT), with 20 young adults, ages 18- to 24-years-old, newly diagnosed with HIV, along with 10 healthcare providers. Through systematic qualitative analysis, we found that young PLWH face barriers to treatment initiation in three SAT domains: (1) stigmatizing social norms (social regulation processes); (2) challenges coping with a new diagnosis (self-regulation processes); and (3) anticipated stigma in the clinic environment (contextual factors). Participants shared that a proposed community-based Youth Treatment Club for newly diagnosed youth would be an acceptable strategy to promote ART initiation. They emphasized that it should include supportive peers, trained facilitator support for counseling and education, and a youth-friendly environment.