Biology subjects

Yamoah, K.

Publications and source records attributed to Yamoah, K..

4 recordsLinked to original sources

bioRxiv2024

Oncogenic Alterations, Race, and Survival in US Veterans with Metastatic Prostate Cancer Undergoing Somatic Tumor Next Generation Sequencing

PurposeNational guidelines recommend next generation sequencing (NGS) of tumors in patients diagnosed with metastatic prostate cancer (mPCa) to identify potential actionable alterations. We sought to describe the spectrum and frequency of alterations in PCa-related genes and pathways, as well as associations with self-identified race/ethnicity, and overall survival in US Veterans. Patients and MethodsThis retrospective cohort study included Non-Hispanic Black (NHB) and Non-Hispanic white (NHW) Veterans with mPCa who obtained NGS through the Veterans Affairs National Precision Oncology Program. 45 genes in seven canonical or targetable mPCa pathways were evaluated in addition to TMB and MSI status. Multivariable logistic regression evaluated associations between race/ethnicity and genomic alteration frequencies. Cox proportional hazards models were used to determine associations between race/ethnicity, specific gene/pathway alteration, and overall survival. Results5,015 Veterans with mPCa who had NGS conducted were included (1,784 NHB, 3,231 NHW). NHB Veterans were younger, had higher PSA at diagnosis, were less likely to report Agent Orange exposure, and resided in more deprived neighborhoods compared to NHW Veterans. Nine of the top ten most commonly altered genes were the same in NHB v NHW Veterans; however, the frequencies of alterations varied by race/ethnicity. NHB race/ethnicity was associated with higher odds of genomic alterations in SPOP (OR 1.7 [1.2-2.6]) as well as immunotherapy targets (OR 1.7 [1.1-2.7]) including MSI high status (OR 3.1 [1.1-9.4]). Furthermore, NHB race/ethnicity was significantly associated with lower odds of genomic alterations in the AKT/PI3K pathway (OR 0.6 [0.4-0.7]), AR axis (OR 0.7 [0.5-0.9]), and tumor suppressor genes (OR 0.7 [0.5-0.8]). Cox proportional hazards modelling stratified by race/ethnicity demonstrated alterations in tumor suppressor genes including TP53 were associated with shorter OS in both NHB (HR 1.54 [1.13-2.11] and NHW individuals (HR 1.52 [1.25-1.85]). ConclusionIn the equal access VA healthcare setting, Veterans undergoing NGS for mPCa exhibited differences in alteration frequencies in both actionable and non-actionable pathways that may be associated with survival. This analysis affirms the utility of genomic testing for identifying candidates irrespective of race/ethnicity for precision oncology treatments, which could contribute to equitable outcomes in patients with mPCa.

genomics↗

bioRxiv2024

Nanoparticles use magnetoelectricity to target and eradicate cancer cells

This study presents the first in vivo and in vitro evidence of an externally controlled, predictive, MRI-based nanotheranostic agent capable of cancer cell specific targeting and killing via irreversible electroporation (IRE) in solid tumors. The rectangular-prism-shaped magnetoelectric nanoparticle is a smart nanoparticle that produces a local electric field in response to an externally applied magnetic field. When externally activated, MENPs are preferentially attracted to the highly conductive cancer cell membranes, which occurs in cancer cells because of dysregulated ion flux across their membranes. In a pancreatic adenocarcinoma murine model, MENPs activated by external magnetic fields during magnetic resonance imaging (MRI) resulted in a mean three-fold tumor volume reduction (62.3% vs 188.7%; P < .001) from a single treatment. In a longitudinal confirmatory study, 35% of mice treated with activated MENPs achieved a durable complete response for 14 weeks after one treatment. The degree of tumor volume reduction correlated with a decrease in MRI T2* relaxation time (r = .351; P = .039) which suggests that MENPs have a potential to serve as a predictive nanotheranostic agent at time of treatment. There were no discernable toxicities associated with MENPs at any timepoint or on histopathological analysis of major organs. MENPs are a noninvasive alternative modality for the treatment of cancer. SummaryWe investigated the theranostic capabilities of magnetoelectric nanoparticles (MENPs) combined with MRI via a murine model of pancreatic adenocarcinoma. MENPs leverage the magnetoelectric effect to convert an applied magnetic field into local electric fields, which can induce irreversible electroporation of tumor cell membranes when activated by MRI. Additionally, MENPs modulate MRI relaxivity, which can be used to predict the degree of tumor ablation. Through a pilot study (n=21) and a confirmatory study (n=27), we demonstrated that, [≥]300 {micro}g of MRI-activated MENPs significantly reduced tumor volumes, averaging a three-fold decrease as compared to controls. Furthermore, there was a direct correlation between the reduction in tumor T2 relaxation times and tumor volume reduction, highlighting the predictive prognostic value of MENPs. Six of 17 mice in the confirmatory studys experimental arms achieved a durable complete response, showcasing the potential for durable treatment outcomes. Importantly, the administration of MENPs was not associated with any evident toxicities. This study presents the first in vivo evidence of an externally controlled, MRI-based, theranostic agent that effectively targets and treats solid tumors via irreversible electroporation while sparing normal tissues, offering a new and promising approach to cancer therapy.

bioengineering↗

bioRxiv2021

Macrophage-derived cholesterol contributes to therapeutic resistance in prostate cancer

Tumor-associated macrophages are key immune cells associated with cancer progression. Here we sought to determine the role of macrophages in castration-resistant prostate cancer (CRPC) using a syngeneic model that reflected the mutational landscape of the disease. A transcriptomic analysis of CRPC tumors following macrophage depletion revealed lower molecular signatures for steroid and bile acid synthesis, indicating potential perturbation of cholesterol metabolism. Since cholesterol is the precursor of the five major classes of steroid hormones, we reasoned that macrophages were regulating androgen biosynthesis within the prostate tumor microenvironment. Indeed, macrophage depletion reduced the levels of androgens within prostate tumors and restricted androgen receptor (AR) nuclear localization in vitro and in vivo. Macrophages were cholesterol rich and had the ability to transfer cholesterol to tumor cells in vitro, and AR nuclear translocation was inhibited by activation of Liver X Receptor (LXR)-{beta}, the master regulator of cholesterol homeostasis. Finally, combining macrophage depletion with androgen deprivation therapy increased survival, supporting the therapeutic potential of targeting macrophages in CRPC.

cancer biology↗

bioRxiv2019

Commercial gene expression tests for prostate cancer prognosis provide paradoxical estimates of race-specific risk

BackgroundCommercial gene expression signatures of prostate cancer (PCa) prognosis were developed and validated in cohorts of predominantly European American men (EAM). Limited research exists on the value of such signatures in African American men (AAM), who have poor PCa outcomes. We explored differences in gene expression between EAM and AAM for three commercially available panels recommended by the National Comprehensive Cancer Network for PCa prognosis. Materials and Methods: 232 EAM and 95 AAM patients provided radical prostatectomy specimens. Gene expression was quantified using Nanostring for 60 genes spanning the Oncotype DX Prostate, Prolaris, and Decipher panels. A continuous expression-based risk score was approximated for each. Differential expression, intrapanel co-expression and risk by race were assessed.\n\nResults and limitationsClinical and pathologic features were similar between AAM and EAM. Differential expression by race was observed for 48% of genes measured, though the magnitudes of expression differences were small. Coexpression patterns were more strongly preserved by race group for Oncotype DX and Decipher versus Prolaris (integrative correlations of 0.87, 0.73, and 0.62, respectively). Poorer prognosis was estimated in EAM versus AAM for Oncotype DX (p < 0.001), whereas no difference in prognosis was predicted between AAM and EAM using Prolaris or Decipher (p > 0.05). Replication of our findings directly on the commercial panels with long-term follow-up is warranted.\n\nConclusionsDue to observed racial differences across three commercial gene expression panels for PCa prognosis, caution is warranted when applying these panels in clinical decision-making in AAM.

epidemiology↗