Biology subjects

Potluri, S.

Publications and source records attributed to Potluri, S..

7 recordsLinked to original sources

bioRxiv2026

ImmunoPheno: A Computational Framework for Data-Driven Design and Analysis of Immunophenotyping Experiments

Immunophenotyping is fundamental to characterizing tissue cellular composition, pathogenic processes, and immune infiltration, yet its accuracy and reproducibility remain constrained by heuristic antibody panel design and manual gating. Here, we present ImmunoPheno, an open-source computational platform that repurposes large-scale single-cell proteo-transcriptomic data to guide immunophenotyping experimental design and analysis. ImmunoPheno integrates existing datasets to automate the design of optimal antibody panels, gating strategies, and cell identity annotation. We used ImmunoPheno to construct a harmonized reference (HICAR) comprising 390 monoclonal antibodies and 93 human immune cell populations. Leveraging this resource, we algorithmically designed minimal panels to isolate rare populations, such as MAIT cells and pDCs, which we validated experimentally. We further demonstrate accurate cell identity annotation across publicly available and newly generated cytometry datasets spanning diverse technologies, including spatial platforms like CODEX. ImmunoPheno complements expert curation and supports continual expansion, providing a scalable framework to enhance the accuracy, reproducibility, and resolution of immunophenotyping.

bioinformatics↗

bioRxiv2025

Modulating AP-1 enables CAR-T cells to establish an intratumoral PD-1+Tcf1+ stem-like reservoir and overcomes resistance to PD-1 axis blockade

PD-1+Tcf1+ stem-like cells are critical mediators of endogenous T cell responses to PD-1/PD-L1 blockade and are maintained by MHC-dependent interactions with professional antigen-presenting cells (APCs). Unlike conventional T cells, CAR-T cells are activated by intact antigen expressed on tumors, not by peptide/MHC expressed on APCs, restricting their activation to the hostile tumor microenvironment (TME) that may impair preservation of this critical stem-like subset. Indeed, in an autochthonous model of ROR1+ lung cancer that we developed, CAR-T cells targeting the tumor-associated antigen ROR1 were uniformly Tcf1+ prior to infusion but rapidly downregulated Tcf1 in vivo and became terminally exhausted, similar to observations in patients, resulting in faster attrition and no enhancement in response to PD-L1 blockade. We hypothesized that overexpression of AP-1 family transcription factors, which can regulate T cell exhaustion, could enable CAR-Ts to maintain this critical PD-1+Tcf1+ subset within tumors independently of APCs and sensitize them to PD-1/PD-L1 blockade. Overexpression of the AP-1 TF c-Jun, but not BATF, improved preservation of PD-1+Tcf1+ CAR-T cells within tumors in a cell-intrinsic manner that correlated with increased persistence deeper within tumors. Notably, c-Jun overexpression alone was insufficient to prevent CAR-T exhaustion in the lung TME, in contrast to prior work in xenograft models, with progressive CAR-T dysfunction correlated with PD-1-dependent downregulation of c-Jun. However, c-Jun overexpression dramatically sensitized CAR-Ts to PD-L1 blockade, which restored c-Jun levels in CAR-Ts, drove log-fold expansion of CAR-Ts within tumors, and induced nearly complete eradication of ROR1+ tumor in highly aggressive models of lung cancer. Altogether, our data show that combination with PD-L1 blockade is necessary to unleash the full potential of c-Jun-overexpressing CAR-T cells in aggressive solid tumors like lung cancer and suggest that strategies to enhance formation of intratumoral PD-1+Tcf1+ reservoirs can overcome CAR-T resistance to PD-1 blockade.

immunology↗

bioRxiv2024

IGPR-1 is phosphorylated on the immunoreceptor tyrosine-based motif, stimulates AKT pathway and supports melanoma growth

Melanoma is a lethal form of skin cancer that impacts one out of every five Americans and ranks as the fifth most prevalent cancer among men and women in the United States. Immunoglobulin (Ig) and Proline-rich Receptor-1 (IGPR-1, also called TMIGD2/CD28H) is closely related to immune checkpoint, CD28/PDL1 family receptors. It controls important cellular processes including, immune cell regulation, cell-cell adhesion, mechanosensing, autophagy, and angiogenesis, and its activity is associated with multiple human malignancies. However, the role and signaling mechanism of IGPR-1 in melanoma remains largely undefined. Here, we report that IGPR-1 is mutated or upregulated in nearly 13% of melanoma and its pro-tumor signaling in melanoma cells is mediated by phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM) tyrosine (Y222). IGPR-1 is phosphorylated at Y222 in human melanoma and cell culture. Phosphorylation of Y222 is context-dependent and is catalyzed by EGFR and Src kinase. Inhibition of EGFR by pharmacological and shRNA strategies inhibited phosphorylation of Y222, whereas stimulation with EGF promoted phosphorylation of Y222 in vivo and recombinant active EGFR catalyzed its phosphorylation in an in vitro kinase assay. In vivo co-immunoprecipitation and in vitro GST-pull-down assays demonstrated that phospho-Y222 facilitates the binding of IGPR-1 with the SH2 domain-containing proteins, SHC1 and SHP2. IGPR-1 stimulates multiple key signal transduction pathways relevant to tumorigenesis, including AKT, mTOR, and MAPK. Mutation of Y222 blocked IGPR-1-mediated activation of AKT and MAPK leading to inhibition of 3D-spheroid tumor growth. By investigating the immunoreceptor tyrosine-based motif signaling of IGPR-1, this study uncovers new findings that could have significant diagnostic and therapeutic implications for melanoma.

cancer biology↗

bioRxiv2023

Gene regulatory network analysis predicts cooperating transcription factor regulons required for FLT3-ITD+ AML growth

AML is a heterogenous disease caused by different mutations. We have previously shown that each mutational sub-type develops its specific gene regulatory network (GRN) with transcription factors interacting with multiple gene modules, many of which are transcription factor genes themselves. Here we hypothesized that highly connected nodes within such networks comprise crucial regulators of AML maintenance. We tested this hypothesis using FLT3-ITD mutated AML as a model and conducted an shRNA drop-out screen informed by this analysis. We show that AML-specific GRNs predict identifying crucial regulatory modules required for AML but not normal cellular growth. Furthermore, our work shows that all modules are highly connected and regulate each other. The careful multi-omic analysis of the role of one (RUNX1) module by shRNA and chemical inhibition shows that this transcription factor and its target genes stabilize the GRN of FLT3-ITD AML and that its removal leads to GRN collapse and cell death.

cancer biology↗

bioRxiv2023

Leukemic stem cells hijack lineage inappropriate signalling pathways to promote their growth

Acute Myeloid Leukemia (AML) is caused by multiple mutations which dysregulate growth and differentiation of myeloid cells. Cells adopt different gene regulatory networks specific to individual mutations, maintaining a rapidly proliferating blast cell population with fatal consequences for the patient if not treated. The most common treatment option is still chemotherapy which targets such cells. However, patients harbour a population of quiescent leukemic stem cells (LSCs) which can emerge from quiescence to trigger relapse after therapy. The processes that allow such cells to re- grow remain unknown. Here, we examined the well characterised t(8;21) AML sub-type as a model to address this question. Using a novel t(8;21) patient-derived xenograft model, we show that t(8;21) LSCs aberrantly activate the VEGF and IL-5 signalling pathways. Both pathways operate within a regulatory circuit consisting of the driver oncoprotein RUNX1::ETO and an AP-1/GATA2 axis allowing LSCs to re-enter the cell cycle while preserving self-renewal capacity.

cancer biology↗

bioRxiv2021

Crosstalk between AML and stromal cells triggers acetate secretion through the metabolic rewiring of stromal cells

Acute myeloid leukaemia (AML) cells interact and modulate components of their surrounding microenvironment into their own benefit. Stromal cells have been shown to support AML survival and progression through various mechanisms. Nonetheless, it is unclear whether AML cells could establish beneficial metabolic interactions with stromal cells. Here, we identify a novel metabolic crosstalk between AML and stromal cells where AML cells prompt stromal cells to secrete acetate for their own consumption to feed the tricarboxylic acid cycle (TCA). By performing transcriptome analysis, tracer-based metabolic NMR analysis and ROS measurements, we observe that stromal cells present a higher rate of glycolysis. We also find that acetate in stromal cells is derived from pyruvate via chemical conversion under the influence of reactive oxygen species (ROS) following ROS transfer from AML to stromal cells via gap junctions. Overall, we present a unique metabolic communication between AML and stromal cells that could potentially be exploited for adjuvant therapy.

cell biology↗

bioRxiv2020

Survival and Proliferation of T-cell Acute Lymphoblastic Leukaemia Depends on mTOR-regulated Glutamine Uptake and EAAT1 Activity

T-cell acute lymphoblastic leukaemia (T-ALL) is a cancer of the immune system. Approximately 20% of paediatric and 50% of adult T-ALL patients have refractory disease or relapse and die from the disease. To improve patient outcome new therapeutics are needed. With the aim to identify new therapeutic targets, we analysed the metabolic adaptations that T-ALL cells exhibit and found that glutamine uptake is essential for their proliferation. Isotope tracing experiments showed that glutamine fuels aspartate synthesis through the TCA cycle and that glutamine and glutamine-derived aspartate together supply three nitrogen atoms in purines and all but one atom in pyrimidine rings. We show that the glutamate-aspartate transporter EAAT1, which is normally only expressed in the CNS, is crucial for glutamine conversion to nucleotides and that T-ALL cell proliferation depends on EAAT1 function. Through this work, we identify EAAT1 as a novel therapeutic target for T-ALL treatment.

cancer biology↗