Biology subjects

Duvvuri, U.

Publications and source records attributed to Duvvuri, U..

6 recordsLinked to original sources

bioRxiv2024

Epidrug Screening Identifies Type I PRMT Inhibitors as Modulators of Lysosomal Exocytosis and Drug Sensitivity in Cancers

Epigenetic changes drive differential gene expression, contributing to oncogenic transformation and drug resistance. Lysosomes are crucial in cell signaling and the sequestration of toxins and chemotherapeutic agents. This sequestration followed by expulsion through lysosomal exocytosis is a factor in drug resistance. The epigenetic regulation of lysosomal exocytosis remains poorly understood. Our research focuses on this regulation, hypothesizing that epigenetic modifier drugs (epidrugs) capable of inhibiting lysosomal exocytosis and could serve as potential therapeutics. Additionally, we investigate their potential synergy with drugs known to be sequestered in lysosomes. To examine this concept, we screened approximately 150 epigenetic drugs targeting various reader, writer, or eraser proteins. These drugs were assessed for their combined cytotoxic effects with cisplatin, their impact on lysosomal exocytosis, and on lysosomal biogenesis. Our findings reveal that among the epidrugs showing synergy with cisplatin and further reducing cell viability in combination, two type I PRMT inhibitors, MS023 and GSK3368715, inhibited lysosomal exocytosis. Notably, neither of these drugs altered the expression of the CLEAR lysosomal biogenesis network of genes, suggesting the involvement of novel regulators in lysosomal functions. To explore the specific components of the trafficking machinery affected by PRMT inhibitors, we conducted an RNA-seq analysis, uncovering several differentially expressed genes (DEGs). In addition to previously described functions such as methylation activity, or DNA repair; these DEGs included those involved in vesicular trafficking, lysosomal enzyme activity and lysosome dynamics, offering potential insights into the mechanism of reduced exocytosis and identifying a novel mode for its regulation. Additionally, both inhibitors exhibited synergy with other drugs known to be sequestered in lysosomes, such as carboplatin, oxaliplatin, sunitinib, and doxorubicin, indicating that inhibition of lysosomal exocytosis may be a common phenomenon for such drugs. These findings underscore the potential of Type I PRMT inhibitors as therapeutic agents in cancer treatment. Consistently, analysis on the publicly available patient data revealed that lower levels of type I PRMTs (PRMT1 and 6) were associated with better patient response to these drugs, further suggesting their potential as drug candidates for combination therapy to enhance chemotherapy efficacy and improve cancer patient survival rates.

cancer biology↗

bioRxiv2023

Polyamine transport inhibition and cisplatin synergistically enhance tumor control through oxidative stress in murine head and neck cancer models

BackgroundSurgery and/or platinum-based chemoradiation remain standard of care for patients with head and neck squamous cell carcinoma (HNSCC). While these therapies are effective in a subset of patients, a substantial proportion experience recurrence or treatment resistance. As cisplatin mediates cytotoxicity through oxidative stress while polyamines play a role in redox regulation, we posited that combining cisplatin with polyamine transport inhibitor, AMXT-1501, would increase oxidative stress and tumor cell death in HNSCC cells. MethodsCell proliferation was measured in syngeneic mouse HNSCC cell lines treated with cisplatin {+/-} AMXT-1501. Synergy was determined by administering cisplatin and AMXT-1501 at a ratio of 1:10 to cancer cells in vitro. Cancer cells were transferred onto mouse flanks to test the efficacy of treatments in vivo. Reactive oxygen species (ROS) were measured. Cellular apoptosis was measured with flow cytometry using Annexin V/PI staining. High-performance liquid chromatography (HPLC) was used to quantify polyamines in cell lines. Cell viability and ROS were measured in the presence of exogenous cationic amino acids. ResultsThe combination of cisplatin and AMXT-1501 synergize in vitro on HNSCC cell lines. In vivo combination treatment resulted in tumor growth inhibition greater than either treatment individually. The combination treatment increased ROS production and induced apoptotic cell death. HPLC revealed the synergistic mechanism was independent of intracellular polyamine levels. Supplementation of cationic amino acids partially rescued cancer cell viability and reduced ROS. ConclusionAMXT-1501 enhances the cytotoxic effects of cisplatin in vitro and in vivo in aggressive HNSCC cell lines through a polyamine-independent mechanism.

cancer biology↗

bioRxiv2023

Lysosomal mitochondrial interaction promotes tumor growth in squamous cell carcinoma of the head and neck

Tumor growth and proliferation are regulated by numerous mechanisms. Communication between intracellular organelles has recently been shown to regulate cellular proliferation and fitness. The way lysosomes and mitochondria communicate with each other (lysosomal/mitochondrial interaction) is emerging as a major determinant of tumor proliferation and growth. About 30% of squamous carcinomas (including squamous cell carcinoma of the head and neck, SCCHN) overexpress TMEM16A, a calcium-activated chloride channel, which promotes cellular growth and negatively correlates with patient survival. TMEM16A has recently been shown to drive lysosomal biogenesis, but its impact on mitochondrial function is unclear. Here, we show that (1) patients with high TMEM16A SCCHN display increased mitochondrial content specifically complex I; (2) In vitro and in vivo models uniquely depend on mitochondrial complex I activity for growth and survival; (3) {beta}-catenin/NRF2 signaling is a critical linchpin that drives mitochondrial biogenesis, and (4) mitochondrial complex I and lysosomal function are codependent for proliferation. Taken together, our data demonstrate that LMI drives tumor proliferation and facilitates a functional interaction between lysosomes and mitochondria. Therefore, inhibition of LMI may serve as a therapeutic strategy for patients with SCCHN.

cancer biology↗

bioRxiv2022

7-UP: generating in silico CODEX from a small set of immunofluorescence markers

Multiplex immunofluorescence (mIF) assays multiple protein biomarkers on a single tissue section. Recently, high-plex CODEX (co-detection by indexing) systems enable simultaneous imaging of 40+ protein biomarkers, unlocking more detailed molecular phenotyping, leading to richer insights into cellular interactions and disease. However, high-plex imaging can be slower and more costly to collect, limiting its applications, especially in clinical settings. We propose a machine learning framework, 7-UP, that can computationally generate in silico 40-plex CODEX at single-cell resolution from a standard 7-plex mIF panel by leveraging cellular morphology. We demonstrate the usefulness of the imputed biomarkers in accurately classifying cell types and predicting patient survival outcomes. Furthermore, 7-UPs imputations generalize well across samples from different clinical sites and cancer types. 7-UP opens the possibility of in silico CODEX, making insights from high-plex mIF more widely available.

bioinformatics↗

bioRxiv2022

SPACE-GM: geometric deep learning of disease-associated microenvironments from multiplex spatial protein profiles.

Multiplexed immunofluorescence imaging enables high-dimensional molecular profiling at subcellular resolution. However, learning disease-relevant cellular environments from these rich imaging data is an open challenge. We developed SPAtial CEllular Graphical Modeling (SPACE-GM), a geometric deep learning framework that flexibly models tumor microenvironments (TMEs) as cellular graphs. We applied SPACE-GM to 658 head-and-neck and colorectal human cancer samples assayed with 40-plex immunofluorescence imaging to identify spatial motifs associated with cancer recurrence and patient survival after immunotherapy. SPACE-GM is substantially more accurate in predicting patient outcomes than previous approaches for modeling spatial data using neighborhood cell-type compositions. Computational interpretation of the disease-relevant microenvironments identified by SPACE-GM generates insights into the effect of spatial dispersion of tumor cells and granulocytes on patient prognosis.

bioinformatics↗

bioRxiv2020

Recurrent human papillomavirus-related head and neck cancer undergoes metabolic re-programming and is driven by oxidative phosphorylation

Human papillomavirus (HPV) infection drives the development of some head and neck cancer squamous cell carcinomas (HNSC). This disease is rapidly increasing in incidence worldwide. Although these tumors are sensitive to treatment, ~10% of patients fail therapy. However, the mechanisms that underlie treatment failure remain unclear. Here, we show that the oxidative phosphorylation (OXPHOS) pathway is enriched in recurrent HPV-associated HNSC and may contribute to treatment failure. Nrf2-enriched HNSC samples from the Cancer Genome Atlas with enrichment in OXPHOS, fatty acid metabolism, Myc, Mtor, ROS, and glycolytic signaling networks exhibited worse survival. HPV-positive HNSC cells demonstrated sensitivity to the OXPHOS inhibitor, IACS-010759, in a Nrf2-dependent manner. Further, using murine xenograft models, we identified Nrf2 as a driver of tumor growth. Mechanistically, Nrf2 drives ROS and mitochondrial respiration, and Nrf2 is a critical regulator of redox homeostasis that can be crippled by disruption of OXPHOS. Nrf2 also mediated cisplatin sensitivity in endogenously overexpressing primary HPV-related HNSC cells. Cisplatin treatment demonstrated Nrf2-dependent synergy with OXPHOS inhibition. These results unveil a paradigm shifting translational target harnessing Nrf2-mediated metabolic reprogramming in HPV-related HNSC.

cancer biology↗