Biology subjects

Kukreja, S.

Publications and source records attributed to Kukreja, S..

6 recordsLinked to original sources

bioRxiv2026

A tumor-cell MHC-II program is associated with checkpoint-blockade outcomes across stages of bladder cancer

Purpose: A minority of patients with bladder cancer derive lasting benefit from immunotherapy, and current biomarkers capture only part of the biology. We evaluated whether tumor-cell MHC class II defines an immune state associated with outcome across disease stages and after PD-1/PD-L1 blockade. Experimental Design: We localized differential MHC-II activity to malignant epithelial cells by single-nucleus and single-cell RNA sequencing and confirmed HLA-DR expression by immunohistochemistry in 122 specimens. Chromatin profiling and IFN-{gamma} stimulation of cell lines and primary tumors supported derivation of an 11-gene tumor-cell program. Associations were tested in 434 patients with non-muscle-invasive disease, 82 receiving neoadjuvant pembrolizumab, and 288 receiving atezolizumab for metastatic disease. Results: Tumor-cell MHC-II was present in approximately one third of bladder cancers, and malignant cells accounted for the differential signal between MHC-II-high and MHC-II-low tumors. The program was inducible by IFN-{gamma} through JAK/STAT signaling. Within luminal non-muscle-invasive disease, MHC-II-low status was associated with progression (HR 3.31, 95% CI 1.37 to 7.99). In PURE-01, the 11-gene program was associated with pathological complete response (52% versus 24%, p = 0.018) and recurrence-free survival (p = 0.0054), retaining an independent association in models including tumor mutational burden and PD-L1. In bladder-primary metastatic disease, program-high status was associated with overall survival in unadjusted analysis (HR 0.62, 95% CI 0.44 to 0.89); the association did not extend to upper tract tumors (interaction p = 0.0018). Conclusions: Tumor-cell MHC-II defines an inducible state associated with outcomes across bladder cancer stages and after checkpoint blockade, supporting prospective evaluation by RNA and immunohistochemistry.

cancer biology↗

bioRxiv2025

EED Maintains the Small Cell Lung Cancer Neuroendocrine Phenotype and Drives Lung Cancer Histological Transformation

Lung cancer histological subtypes include lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC). While typically distinct, combined LUAD/SCLC histology tumors occur, and LUAD can transform into SCLC as a resistance mechanism to targeted therapies, especially in EGFR-Mutant LUADs with RB1/TP53-inactivation. Although PRC2 complex expression increases during this transformation, its functional role has remained unclear. Using CRISPR-based autochthonous immunocompetent GEMMs, we demonstrate that inactivation of EED, the core PRC2 scaffolding subunit, impairs SCLC tumorigenesis and drives histological transformation from ASCL1-positive SCLC to LUAD through a transient NEUROD1-positive intermediate state. Mechanistically, EED loss de-represses bivalent genes co-marked by H3K27me3 and H3K4me3, including LUAD oncogenic RAS, PI3K, and MAPK pathway genes, to promote transformation to LUAD. Consistently, these same signaling genes are bivalently repressed in human SCLC patient-derived xenograft (PDX) tumors, suggesting a conserved PRC2-dependent mechanism to repress LUAD lineage oncogenic signaling to maintain the SCLC neuroendocrine identity. In a complementary EGFR-mutant LUAD GEMM with RB1/TP53 inactivation, EED was required for LUAD-to-SCLC transformation and distant metastasis upon EGFR withdrawal. These findings identify the PRC2 complex as a key epigenetic enforcer of SCLC neuroendocrine identity and nominate EED inhibition as a potential strategy to block SCLC transformation in high-risk LUAD.

cancer biology↗

bioRxiv2025

Epigenetic Subtypes of High-Grade T1 Bladder Cancer Reveal Intra-Tumor Heterogeneity and Distinct Interactions with Tumor Microenvironment.

High-Grade T1 (HGT1) Non-Muscle Invasive Bladder Cancer (NMIBC) is a clinically heterogeneous disease, characterized by unpredictable treatment responses and limited tools for recurrence prediction. Although molecular classification efforts have been made, patient stratification still primarily relies on clinicopathological features, which offer limited clinical precision. In this study, we integrated chromatin profiling in bulk with single-nuclei(sn) RNA-seq, immunohistochemistry and spatial transcriptomics to define epigenetic subtypes of HGT1, characterize their heterogeneity, and investigate tumor-microenvironment interactions. Our findings reveal distinct chromatin profiles differentiating urothelial (URO) and micropapillary (MP) histological variants of high-risk HGT1. We identified three epigenetic states: two within the URO group, luminal-like inflammatory (LLI) and basal-like (BL), and a separate signature unique to MP tumors. Single-cell and spatial resolution approaches validated intratumoral heterogeneity and provided insight into subtype-specific microenvironmental contexts. Notably, [~]40% of URO tumors exhibited spatially distinct coexisting LLI and BL components. BL regions showed enrichment for angiogenesis and hypoxia pathways and were preferentially located near vascular stroma, while LLI regions showed to be located at the core of the tumor. MP tumors featured a markedly different microenvironment, characterized by diverse populations of cancer-associated fibroblasts (CAFs) and M2-polarized macrophages intermingled with tumor cells, suggesting a more immunosuppressive niche which could account for their worse clinical outcome. URO tumors, by comparison, showed a more immune-excluded phenotype. These findings provide a detailed molecular and spatial map of bladder cancer heterogeneity, highlighting how distinct epigenetic subtypes and histological variants are associated with tumor architecture and microenvironmental interactions. Our data underscore the need for subtype-specific therapeutic strategies to more effectively address the complexity already existing at HGT1 bladder cancer.

cancer biology↗

bioRxiv2025

EZH2 alters aggressive variant prostate cancer subtype evolution, but is not required for neuroendocrine prostate cancer

Advanced prostate cancer (PrCa) remains a leading cause of cancer-related death among men because nearly all patients progress on standard therapy that targets androgen receptor (AR) signaling. An important mechanism driving therapeutic resistance is lineage plasticity, the ability of PrCa cells to reprogram into lineage variants like neuroendocrine (NE) PrCa that no longer depend on AR signaling. The histone methyltransferase EZH2 has been implicated in PrCa lineage plasticity and EZH2 inhibitors are being evaluated clinically for the treatment of PrCa. Here we test how Ezh2 impacts the evolution of PrCa lineage plasticity using genetically engineered mice and human patient data. Reduced Ezh2 expression diversifies the evolution of PrCa lineage variants, including a newly discovered variant with high expression of neurofilament genes, in both mice and humans. Lineage variant diversification is associated with activation of Klf transcription factor programs and AR cistrome reprogramming that is normally repressed by Ezh2. These findings advance the understanding of PrCa lineage plasticity and have implications for using EZH2 as a target for PrCa therapy.

cancer biology↗

bioRxiv2022

Evidence for RNA or protein transport from somatic tissues to the male reproductive tract in mouse

The development of tools to manipulate the mouse genome, including knockout and transgenic technology, revolutionized our ability to explore gene function in mammals. Moreover, for genes that are expressed in multiple tissues or at multiple stages of development, the use of tissue-specific expression of the Cre recombinase allows gene function to be perturbed in specific cell types and/or at specific times. However, it is well known that putative tissue-specific promoters often drive unanticipated "off target" expression. In our efforts to explore the biology of the male reproductive tract, we unexpectedly found that expression of Cre in the central nervous system resulted in recombination in the epididymis, a tissue where sperm mature for ~1-2 weeks following the completion of testicular development. Remarkably, we not only observed reporter expression in the epididymis when Cre expression was driven from neuron-specific transgenes, but also when Cre expression in the brain was induced from an AAV vector carrying a Cre expression construct. A surprisingly wide range of Cre drivers - including six different neuronal promoters as well as the adipose-specific AdipoQ Cre promoter - exhibited off target recombination in the epididymis, with a subset of drivers also exhibiting unexpected activity in other tissues such as the reproductive accessory glands. Finally, using a combination of parabiosis and serum transfer experiments, we find evidence supporting the hypothesis that Cre may be trafficked from its cell of origin to the epididymis through the circulatory system. Together, our findings should motivate extreme caution when interpreting conditional alleles, and suggest the exciting possibility of inter-tissue RNA or protein trafficking in modulation of reproductive biology.

genetics↗

bioRxiv2018

Transitions in paternal dominance regulate offspring growth and metabolic transcription

Parental effects are an important source of adaptive traits. By contrast, parental effects failing to regulate offspring phenotype to fit current conditions could be deleterious. Although adaptive parental responses to single cues have been identified, we lack an understanding of the reversibility of parental effects across breeding cycles in a fluctuating environment. Social status of parents can occasionally fluctuate and, in turn, influence high-fitness pathways available to offspring. We show that social competition status results in robust parental effects on growth in mice. Dominant males produce faster growing offspring because of status related cues, not genetic associations. The timing, effect-size, and sex-specificity of this paternal effect are modulated by maternal experience. We experimentally demonstrate that status-ascending males produce heavier sons than before, and status-descending males produce lighter sons than before. Paternal status predicts genome-wide transcription in the liver, including transcriptional networks controlling xenobiotic and fatty acid metabolism, and oxidative phosphorylation. Our study demonstrates that paternal social status reversibly conditions offspring growth in naturalistic environments.

evolutionary biology↗