Frequent clonal relations between metastases and non-index prostate cancer lesions

\u3cp\u3ePrimary prostate cancer lesions are clonally heterogeneous and often arise independently. In contrast, metastases were reported to share a monoclonal background. Because prostate cancer mortality is the consequence of distant metastases, prevention of metastatic outgrowth by primary tumor ablation is the main focus of treatment for localized disease. Focal therapy is targeted ablation of the primary index lesion, but it is unclear whether remaining primary lesions metastasize at a later stage. In this study, we compared copy number aberration profiles of primary prostate cancer lesions with matching pelvic lymph node metastases of 30 patients to establish clonality between a lymph node metastasis and multiple primary lesions within the same patient. Interestingly, in 23.3% of the cases, the regional metastasis was not clonally linked to the index primary lesion. These findings suggest that focal ablation of only the index lesion is potentially an undertreatment of a significant proportion of prostate cancer patients.\u3c/p\u3

Frequent clonal relations between metastases and non-index prostate cancer lesions

Primary prostate cancer lesions are clonally heterogeneous and often arise independently. In contrast, metastases were reported to share a monoclonal background. Because prostate cancer mortality is the consequence of distant metastases, prevention of metastatic outgrowth by primary tumor ablation is the main focus of treatment for localized disease. Focal therapy is targeted ablation of the primary index lesion, but it is unclear whether remaining primary lesions metastasize at a later stage. In this study, we compared copy number aberration profiles of primary prostate cancer lesions with matching pelvic lymph node metastases of 30 patients to establish clonality between a lymph node metastasis and multiple primary lesions within the same patient. Interestingly, in 23.3% of the cases, the regional metastasis was not clonally linked to the index primary lesion. These findings suggest that focal ablation of only the index lesion is potentially an undertreatment of a significant proportion of prostate cancer patients

Agent-based modeling of the prostate tumor microenvironment uncovers spatial tumor growth constraints and immunomodulatory properties

Abstract Inhibiting androgen receptor (AR) signaling through androgen deprivation therapy (ADT) reduces prostate cancer (PCa) growth in virtually all patients, but response may be temporary, in which case resistance develops, ultimately leading to lethal castration-resistant prostate cancer (CRPC). The tumor microenvironment (TME) plays an important role in the development and progression of PCa. In addition to tumor cells, TME-resident macrophages and fibroblasts express AR and are therefore also affected by ADT. However, the interplay of different TME cell types in the development of CRPC remains largely unexplored. To understand the complex stochastic nature of cell-cell interactions, we created a PCa-specific agent-based model (PCABM) based on in vitro cell proliferation data. PCa cells, fibroblasts, “pro-inflammatory” M1-like and “pro-tumor” M2-like polarized macrophages are modeled as agents from a simple set of validated base assumptions. PCABM allows us to simulate the effect of ADT on the interplay between various prostate TME cell types. The resulting in vitro growth patterns mimic human PCa. Our PCABM can effectively model hormonal perturbations by ADT, in which PCABM suggests that CRPC arises in clusters of resistant cells, as is observed in multifocal PCa. In addition, fibroblasts compete for cellular space in the TME while simultaneously creating niches for tumor cells to proliferate in. Finally, PCABM predicts that ADT has immunomodulatory effects on macrophages that may enhance tumor survival. Taken together, these results suggest that AR plays a critical role in the cellular interplay and stochastic interactions in the TME that influence tumor cell behavior and CRPC development

Exploring the Onset and Progression of Prostate Cancer through a Multicellular Agent-based Model

Over 10% of men will be diagnosed with prostate cancer during their lifetime. Arising from luminal cells of the prostatic acinus, prostate cancer is influenced by multiple cells in its microenvironment. To expand our knowledge and explore means to prevent and treat the disease, it is important to understand what drives the onset and early stages of prostate cancer. In this study, we developed an agent-based model of a prostatic acinus including its microenvironment, to allow for in silico studying of prostate cancer development. The model was based on prior reports and in-house data of tumor cells cocultured with cancer-associated fibroblasts (CAF) and protumor and/or antitumor macrophages. Growth patterns depicted by the model were pathologically validated on hematoxylin and eosin slide images of human prostate cancer specimens. We identified that stochasticity of interactions between macrophages and tumor cells at early stages strongly affect tumor development. In addition, we discovered that more systematic deviations in tumor development result from a combinatorial effect of the probability of acquiring mutations and the tumor-promoting abilities of CAFs and macrophages. In silico modeled tumors were then compared with 494 patients with cancer with matching characteristics, showing strong association between predicted tumor load and patients' clinical outcome. Our findings suggest that the likelihood of tumor formation depends on a combination of stochastic events and systematic characteristics. While stochasticity cannot be controlled, information on systematic effects may aid the development of prevention strategies tailored to the molecular characteristics of an individual patient. SIGNIFICANCE: We developed a computational model to study which factors of the tumor microenvironment drive prostate cancer development, with potential to aid the development of new prevention strategies.</p

Multiplex gene editing by CRISPR-Cpf1 using a single crRNA array

Targeting of multiple genomic loci with Cas9 is limited by the need for multiple or large expression constructs. Here we show that the ability of Cpf1 to process its own CRISPR RNA (crRNA) can be used to simplify multiplexed genome editing. Using a single customized CRISPR array, we edit up to four genes in mammalian cells and three in the mouse brain, simultaneously.</p

DNA-guided DNA cleavage at moderate temperatures by Clostridium butyricum Argonaute

Prokaryotic Argonaute proteins (pAgos) constitute a diverse group of endonucleases of which some mediate host defense by utilizing small interfering DNA guides (siDNA) to cleave complementary invading DNA. This activity can be repurposed for programmable DNA cleavage. However, currently characterized DNA-cleaving pAgos require elevated temperatures (≥65°C) for their activity, making them less suitable for applications that require moderate temperatures, such as genome editing. Here, we report the functional and structural characterization of the siDNA-guided DNA-targeting pAgo from the mesophilic bacterium Clostridium butyricum (CbAgo). CbAgo displays a preference for siDNAs that have a deoxyadenosine at the 5'-end and thymidines at nucleotides 2-4. Furthermore, CbAgo mediates DNA-guided DNA cleavage of AT-rich double stranded DNA at moderate temperatures (37°C). This study demonstrates that certain pAgos are capable of programmable DNA cleavage at moderate temperatures and thereby expands the scope of the potential pAgo-based applications.BN/Chirlmin Joo La