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Biology subjects

Ghoreyshi, Z.

Publications and source records attributed to Ghoreyshi, Z..

2 recordsLinked to original sources

A memory-driven model of phenotypic adaptation for anticipating the emergence of enzalutamide resistance in prostate cancer

While contemporary cancer treatment strategies have significantly prolonged the lives of patients, therapeutic resistance remains a predominant cause of disease progression and cancerrelated deaths. Cancer therapy often induces gene regulatory responses that promote cell survival in the face of this therapy. Herein, we sought to develop a stochastic model of the response to repeat therapeutic challenge. This model integrates reinforcement learning to account for environmental history-dependent cellular transitions and growth dynamics. When applied to prostate cancer, this memory-driven adaptive model successfully captures the experimentally-observed dynamics of drugsensitive and drug-resistant LNCaP cells under varying dosing schedules of androgen receptor blockade with enzalutamide (enza), significantly outperforming traditional transition models that lack history dependence. This performance is especially evident in the ability of our approach to robustly predict stochastic fluctuations in cancer cell population sizes across the entire disease trajectory, including subtle, later-emerging responses following initial therapy. The model was further evaluated by predicting the control of resistant cells in an enza environment by modeling inhibition of the p38/MAPK pro-survival stress axis, which was then validated experimentally. Lastly, we developed and applied a patient-calibrated model using prostate-specific antigen (PSA) data from clinical patient cohorts undergoing intermittent androgen deprivation therapy. Our model accurately predicts the PSA dynamics under repeated treatment cycles and effectively distinguishing between patients who respond and those who do not respond to treatment, thereby providing quantitative insight into prostate cancer progression. We anticipate that such adaptive modeling frameworks will be broadly useful for predicting cancer treatment outcomes and developing optimized adaptive therapeutic strategies tailored to patient-specific disease dynamics in additional cancer contexts.

evolutionary biology↗

How Modulation of the Tumor Microenvironment Drives Cancer Immune Escape Dynamics

Metastatic disease is the leading cause of cancer-related death, despite recent advances in therapeutic interventions. Prior modeling approaches have accounted for the adaptive immune systems role in combating tumors, which has led to the development of stochastic models that explain cancer immunoediting and tumor-immune co-evolution. However, cancer immunemediated dormancy, wherein the adaptive immune system maintains a micrometastatic population by keeping its growth in check, remains poorly understood. Immune-mediated dormancy can significantly delay the emergence (and therefore detection) of metastasis. An improved quantitative understanding of this process will thereby improve our ability to identify and treat cancer during the micrometastatic period. Here, we introduce a generalized stochastic model that incorporates the dynamic effects of immunomodulation within the tumor microenvironment on T cell-mediated cancer killing. This broad class of nonlinear birth-death model can account for a variety of cytotoxic T cell immunosuppressive effects, including regulatory T cells, cancer-associated fibroblasts, and myeloid-derived suppressor cells. We develop analytic expressions for the likelihood and mean time of immune escape. We also develop a method for identifying a corresponding diffusion approximation applicable to estimating population dynamics across a wide range of nonlinear birth-death processes. Lastly, we apply our model to estimate the nature and extent of immunomodulation that best explains the timing of disease recurrence in bladder and breast cancer patients. Our findings quantify the effects that stochastic tumor-immune interaction dynamics can play in the timing and likelihood of disease progression. Our analytical approximations provide a method of studying population escape in other ecological contexts involving nonlinear transition rates.

cancer biology↗