Biology subjects

Raveenthiraraj, S.

Publications and source records attributed to Raveenthiraraj, S..

6 recordsLinked to original sources

bioRxiv2025

Glutamine antagonism suppresses tumor growth in adrenocortical carcinoma through inhibition of de novo nucleotide biosynthesis

Dysregulation of cellular metabolism is a hallmark of cancer, which remains poorly understood in adrenocortical carcinoma (ACC). Here, we dissected ACC metabolism by integrating transcriptional profiling from human and mouse ACC, targeted tissue metabolomics from a mouse ACC model, and untargeted serum metabolomics from a large patient cohort, providing cross-species validation of metabolic rewiring in ACC. This study revealed global metabolic dysregulation, involving glutamine-dependent pathways such as non-essential amino-acid and hexosamine biosynthesis, nucleotide metabolism, and glutathione biosynthesis, suggesting glutamine catabolism is a critical metabolic vulnerability in ACC. Treatment with glutamine antagonists 6-Diazo-5-Oxo-L-Norleucine (DON) and JHU-083 elicited robust anti-tumor responses. Mechanistic studies revealed DONs anti-tumor effect was primarily driven by selective inhibition of glutamine-fueled de novo nucleotide biosynthesis. Additionally, DON led to DNA damage, which yielded potent synergism with inhibition of the DNA damage response pathway. Collectively, this work highlights glutamine metabolism as a central metabolic dependency and therapeutic target in ACC. HighlightsO_LIMouse and human ACC share conserved transcriptional-metabolic programs, revealing Gln metabolism as a central, targetable vulnerability. C_LIO_LITargeted tissue metabolomic analysis in a mouse model of ACC validates dysregulation in Gln-dependent metabolic pathways. C_LIO_LITargeting of Gln metabolism with JHU-083 (6-diazo-5-oxo-L-norleucine (DON) pro-drug) achieves marked inhibition of tumor growth in vivo. C_LIO_LIHigh expression of Gln-metabolizing genes mediating de novo nucleotide biosynthesis is associated with poor prognosis in ACC. C_LIO_LIDON drives nucleotide depletion and DNA damage, leading to potent synergy with inhibition of the DNA damage response. C_LIO_LIUntargeted serum metabolomic analysis in a large cohort of patients with adrenal tumors demonstrates dysregulation of Gln and nucleotide metabolism in ACC. C_LI

cancer biology↗

bioRxiv2025

Loss of WNT2B Increases Progression from Dysplasia to Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related deaths in the United States, and upregulation of the WNT pathway is a primary driver in most cases. However, the role of individual WNT proteins in the development of CRC remains poorly understood. Our previous studies demonstrated that WNT2B loss-of-function leads to severe intestinal enteropathy in humans and increases chemically-induced colitis in mice, suggesting a protective function in the colon. Therefore, we investigated how loss of WNT2B affects CRC development. We used azoxymethane (AOM)/dextran sodium sulfate (DSS) to model colitis-associated cancer (CAC) and AOM-induced mutagenesis to model sporadic CRC. We measured the number and size of tumors and performed histopathological and molecular analyses. We also analyzed the Cancer Genome Atlas to evaluate WNT2B expression in human colon cancer. In CAC and CRC mouse models, Wnt2b KO mice showed decreased survival and enhanced tumor burden. Moreover, Wnt2b KO mice had larger tumors and enhanced dysplasia, with a higher frequency of animals progressing from adenomas to adenocarcinomas compared to control littermates. Wnt2b KO animals frequently presented with intestinal bleeding and rectum prolapse, which resembles obstructive CRC. Furthermore, WNT2B expression was downregulated in human CRC samples compared to healthy controls, which predicted a significantly lower patient survival. These findings support the conclusion that WNT2B is required for maximal resistance against tumorigenesis and raise the possibility that selectively increasing WNT2B signaling may be a useful colon cancer prevention strategy. SignificanceWNT2B loss-of-function increases colon cancer tumorigenesis. Targeting WNT2B may represent a novel strategy for intestinal diseases with a high risk of neoplastic transformation, potentially decreasing the progression to cancer development.

cancer biology↗

bioRxiv2025

Necrotizing enterocolitis causes increased ileal goblet cell loss in Wnt2b KO mice

WNT2B is Wnt ligand which is able to support intestinal stem cells (ISC) in culture and support the intestinal epithelium in vivo. We have previously shown that WNT2B is critical for resistance to colitis, but not small intestinal injury, in the adult mouse. WNT2B is thought to coordinate with WNT3 in supporting ISC, and we have also shown that WNT3 expression is low in the early postnatal ileum in mice. Here, we hypothesized that WNT2B may be more critical in the small intestine during early development, and we challenged Wnt2b KO mice and controls with experimental necrotizing enterocolitis (NEC) on postnatal days 5-8. Wnt2b KO mice had similar ileum histology and injury scores to control mice. Molecular analyses showed that Wnt2b KO mice have differences in Lgr5 and Tlr4 expression compared to wild type controls in untreated conditions, but under experimental NEC expression of epithelial markers and inflammatory genes associated with NEC were similar to wild type. Periodic acid Schiff positive cells were lower in the villi of Wnt2b KO mice during NEC, however expression of goblet cell markers was not different compared to wild type mice. We also used an organoid-based NEC model to highlight the epithelium in isolation and also found no impact of WNT2B KO in the setting of NEC. These data further affirm that WNT2B is critical for inflammation responses in the mouse colon, but does not appear to play a major role in the small intestine, no matter the developmental period.

developmental biology↗

bioRxiv2023

WNT2B Deficiency Causes Increased Susceptibility to Colitis in Mice and Impairs Intestinal Epithelial Development in Humans

Background and aimsWNT2B is a canonical Wnt ligand previously thought to be fully redundant with other Wnts in the intestinal epithelium. However, humans with WNT2B deficiency have severe intestinal disease, highlighting a critical role for WNT2B. We sought to understand how WNT2B contributes to intestinal homeostasis. MethodsWe investigated the intestinal health of Wnt2b knock out (KO) mice. We assessed the impact of inflammatory challenge to the small intestine, using anti-CD3{chi} antibody, and to the colon, using dextran sodium sulfate (DSS). In addition, we generated human intestinal organoids (HIOs) from WNT2B-deficient human iPSCs for transcriptional and histological analyses. ResultsMice with WNT2B deficiency had significantly decreased Lgr5 expression in the small intestine and profoundly decreased expression in the colon, but normal baseline histology. The small intestinal response to anti-CD3{chi} antibody was similar in Wnt2b KO and wild type (WT) mice. In contrast, the colonic response to DSS in Wnt2b KO mice showed an accelerated rate of injury, featuring earlier immune cell infiltration and loss of differentiated epithelium compared to WT. WNT2B-deficient HIOs showed abnormal epithelial organization and an increased mesenchymal gene signature. ConclusionWNT2B contributes to maintenance of the intestinal stem cell pool in mice and humans. WNT2B deficient mice, which do not have a developmental phenotype, show increased susceptibility to colonic injury but not small intestinal injury, potentially due to a higher reliance on WNT2B in the colon compared to the small intestine. WNT2B deficiency causes a developmental phenotype in human intestine with HIOs showing a decrease in their mesenchymal component and WNT2B-deficient patients showing epithelial disorganization. Data Transparency StatementAll RNA-Seq data will be available through online repository as indicated in Transcript profiling. Any other data will be made available upon request by emailing the study authors.

molecular biology↗

bioRxiv2022

Hepatocyte Growth Factor and β1-integrin signalling axis drives tunneling nanotube formation in A549 lung adenocarcinoma cells

Tunneling nanotubes (TNTs) are thin cytoplasmic protrusions involved in long-distance cellular communication. The presence of TNTs has been found in vivo and in vitro studies in non-small cell lung cancer (NSCLC). Cancer cells transport a range of organelles and signalling molecules along TNTs, to confer a survival phenotype for the recipient cell, contributing toward chemoresistance and malignancy. Despite its important role in cancer progression, the molecular mechanisms underlying TNT formation is not well defined. Within the tumour microenvironment (TME) of NSCLC, hepatocyte growth factor (HGF) and its receptor, c-Met, are mutationally upregulated causing growth, and invasion. In this study, we report a novel crosstalk between HGF/c-Met and {beta}1-integrin involved in the formation of functional TNTs in A549 cells. Through pharmacological inhibitor studies, we discovered Arp2/3 complex, MAPK and PI3K pathways were activated downstream of this crosstalk signalling axis. Furthermore, paxillin was recruited during this key process, localising at the protrusion site of HGF-induced TNTs, and therefore serving as the central link between the upstream and downstream regulators involved. Overall, these results demonstrate a novel strategy to inhibit TNT formation in NSCLC through targeting the HGF/c-Met and {beta}1-integrin signalling axis, thus highlighting the importance of personalised multi-drug targeting in NSCLC.

cancer biology↗

bioRxiv2022

M1 and M2 macrophages differentially regulate colonic crypt renewal.

The colonic epithelium is the most rapidly renewing tissue in the body and is organized into a single cell layer of invaginations called crypts. Crypt renewal occurs through Lgr5+ gut stem cells situated at the crypt base, which divide, produce daughter cells that proliferate, migrate, differentiate into all the cells required for normal gut function (eg. Goblet cells, enterocytes), and are finally shed into the crypt lumen. In health this rapid renewal helps maintain barrier function next to the hostile gut luminal environment that contains microbes and food. In parallel, the peri-cryptal lamina propria hosts the largest monocyte-derived macrophage population in the human body. Different macrophage phenotypes have been associated with intestinal health/intact barrier function, namely M2 compared to M1 macrophages that indicate inflammation/compromised barrier function. However, the direct effect of different macrophage subtypes have on colonic crypt renewal is not well understood. In this study we have utilized a reductionist 3D in vitro co-culture model to determine the regulatory capacity of M1 and M2 macrophages on colonic crypt renewal. We show that colonic crypt proliferation is increased in the presence of M1 or M2 macrophages, while we further demonstrate that a decrease in goblet and tuft cell expression as well as an increase in Lgr5+ stem cell numbers is only achieved through M1-crypt crosstalk in a contact dependent manner.

cell biology↗