Biology subjects

Pisitkun, T.

Publications and source records attributed to Pisitkun, T..

6 recordsLinked to original sources

bioRxiv2026

Mass Spectrometry-Based Profiling of Personalized Immunopeptidomes in Thai Renal Cell Carcinoma

This study profiles the personalized immunopeptidomes of 13 Thai patients with renal cell carcinoma (RCC), addressing a critical knowledge gap in Southeast Asian populations characterized by distinct HLA allele distributions. We combined whole-exome sequencing (WES)-based personalized proteome construction with liquid chromatography-tandem mass spectrometry (LC-MS/MS), using both database-driven searches and de novo peptide sequencing. HLA typing identified seven alleles not previously represented in major immunopeptidome databases, with HLA-A*11:01 being the most frequent (69%). Database-based analysis identified a single tumor-specific neoantigen derived from a mutant JADE2 peptide in the patient with the highest tumor mutational burden, which was validated by a mutant-specific ELISPOT response. In contrast, de novo sequencing revealed numerous non-canonical peptides, a subset of which were supported by proteogenomic validation using PepQuery and detected exclusively in cancer proteomes but not in normal tissue datasets, indicating their potential as tumor-associated antigens. Together, these results establish an integrated and scalable framework for identifying HLA-presented tumor-derived peptides and provide a foundational immunopeptidome resource to support personalized cancer immunotherapy development in Southeast Asia.

systems biology↗

bioRxiv2024

Cgas deficiency promotes tumor growth by supporting B cell persistence and angiogenesis

The cGAS sensor activates STING/IFN signaling, which is crucial for immune defense against pathogens and triggers inflammation in autoimmune diseases and antitumor responses. This study investigated the cGAS-mediated immune response in tumorigenesis using the MC-38 tumor model. Cgas-/- mice exhibited significantly larger tumors and lower survival rates than wild-type (WT) mice. Tumors in Cgas-/- mice showed increased fibrosis and neovascularity. WT mice mounted a more robust T-cell-mediated antitumor response, with higher levels of NK and effector T cells, while Cgas-/- mice showed an expansion of B cells, including regulatory B cells producing IL-10. B cells from tumor-bearing Cgas-/- mice survived better in the tumor- conditioned medium than those from WT mice. B cell depletion significantly reduced tumor size in WT mice but had minimal effect in Cgas-/- mice, where fibrosis and tumor vasculature persisted. Despite B cell depletion, B cells remained in the tumors of Cgas-/- mice, in contrast to WT mice, where their reduction correlated with an increase in CD8+ infiltrating cells. Expression of Tlr7 and Tlr9 remained elevated and unaffected by B cell depletion in Cgas-/- tumors, while Baff expression was higher and further increased after B cell depletion. Cgas-/- B cells promoted angiogenesis, as indicated by enhanced endothelial tube formation. In summary, cGAS deficiency fosters a tumor microenvironment that supports B cell survival, promotes a pro-tumor immune environment, and enhances angiogenesis, contributing to tumor progression.

cancer biology↗

bioRxiv2022

mTORC2 Interactome and Localization Determine Aggressiveness of High-Grade Glioma Cells through Association with Gelsolin

The mTOR complex 2 (mTORC2) has been implicated as a key regulator of glioblastoma cell migration. However, the roles of mTORC2 in the migrational control process have not been entirely elucidated. Here we elaborate that active mTORC2 is crucial for GBM cell motility. Inhibition of mTORC2 impaired cell movement and negatively affected microfilaments and microtubules functions. We also aimed to characterize important players involved in the regulation of cell migration and other mTORC2-mediated cellular processes in GBM cells through the proteomic and bioinformatic analyses. Therefore, we quantitatively characterized the alteration of mTORC2 interactome under selective conditions using affinity-purification mass spectrometry (AP-MS) in glioblastoma. We demonstrated that changes in cell migration ability specifically altered mTORC2-associated proteins. Gelsolin (GSN) was identified as one of the most dynamic proteins. The mTORC2-GSN linkage was mostly highlighted in high-grade glioma cells and shown to connect functional mTORC2 to multiple proteins responsible for directional cell movement in GBM. GSN also mediated membrane localization of mTORC2. Loss of GSN disconnected mTORC2 from numerous cytoskeletal proteins but did not affect mTORC2 integrity. In addition, we reported 86 stable mTORC2 interactome involved with diverse molecular functions, predominantly cytoskeletal remodeling in GBM. Our findings help expand future opportunities for predicting the highly migratory phenotype of brain cancers in the clinical investigation.

cancer biology↗

bioRxiv2021

Unsupervised mining of HLA-I peptidomes reveals new binding motifs and substantial false positives in community database

Modern vaccine designs and studies of human leukocyte antigen (HLA)-mediated immune responses rely heavily on the knowledge of HLA allele-specific binding motifs and computational prediction of HLA-peptide binding affinity. Breakthroughs in HLA peptidomics have considerably expanded the databases of natural HLA ligands and enabled detailed characterizations of HLA-peptide binding specificity. However, cautions must be made when analyzing HLA peptidomics data because identified peptides may be contaminants in mass spectrometry or may weakly bind to the HLA molecules. Here, a hybrid de novo peptide sequencing approach was applied to large-scale mono-allelic HLA peptidomics datasets to uncover new ligands and refine current knowledge of HLA binding motifs. Up to 12-40% of the peptidomics data were low-binding affinity peptides with an arginine or a lysine at the C-terminus and likely to be tryptic peptide contaminants. Thousands of these peptides have been reported in a community database as legitimate ligands and might be erroneously used for training prediction models. Furthermore, unsupervised clustering of identified ligands revealed additional binding motifs for several HLA class I alleles and effectively isolated outliers that were experimentally confirmed to be false positives. Overall, our findings expanded the knowledge of HLA binding specificity and advocated for more rigorous interpretation of HLA peptidomics data that will ensure the high validity of community HLA ligandome databases.

immunology↗

bioRxiv2020

Serratia marcescens secretes proteases and chitinases with larvicidal activity against Anopheles dirus

Vector control, the most efficient tool to reduce mosquito-borne disease transmission, has been compromised by the rise of insecticide resistance. Recent studies suggest the potential of mosquito-associated microbiota as a source for new biocontrol agents or new insecticidal chemotypes. In this study, we identified a strain of Serratia marcescens that has larvicidal activity against Anopheles dirus, an important malaria vector in Southeast Asia. This bacterium secretes heat-labile larvicidal macromolecules when cultured under static condition at 25{degrees}C but not 37{degrees}C. Two major protein bands of approximately 55 kDa and 110 kDa were present in spent medium cultured at 25{degrees}C but not at 37{degrees}C. The Liquid Chromatography-Mass Spectrometry (LC-MS) analyses of these two protein bands identified several proteases and chitinases that were previously reported for insecticidal properties against agricultural insect pests. The treatment with protease and chitinase inhibitors led to a reduction in larvicidal activity, confirming that these two groups of enzymes are responsible for the macromolecules toxicity. Taken together, our results suggest a potential use of these enzymes in the development of larvicidal agents against Anopheles mosquitoes.

microbiology↗

bioRxiv2019

Inhibition of Sting rescues lupus disease by the regulation of Lyn-mediated dendritic cell differentiation

SLE (systemic lupus erythematosus) is an autoimmune disease that causes chronic inflammation and leads to fatality if left untreated. Immune complex-mediated inflammation and type I IFN signaling pathways are one of the mechanisms initiating lupus disease. Signaling through stimulator of interferon genes (STING) leads to the production of type I IFN and inflammatory cytokines. However, the role of STING in lupus mouse models is controversy. Here we demonstrated the mechanisms of STING involving in SLE pathogenesis at the molecular level. The disruption of STING signaling rescued lupus disease in Fcgr2b-deficient mice. STING activated DC facilitated T cell proliferation, which depended on intrinsic expression of STING on DC but not on T cells. Upon STING activation, LYN was recruited and co-localized with STING in bone marrow-derived dendritic cells (BMDC). STING signaling induced phosphorylated LYN and AKT. The inhibition of LYN prohibited STING-induced DC differentiation. Adoptive transfer of STING-activated BMDC into the FCGR2B and STING double-deficiency mice restored lupus phenotypes. These findings provide the proof of concept that inhibition of STING signaling is a promising therapeutic approach for SLE patients.

immunology↗