Biology subjects

Afzal, J.

Publications and source records attributed to Afzal, J..

5 recordsLinked to original sources

bioRxiv2026

Cyclic Hypoxia drives Wnt5a-ROR1 stroma-tumor crosstalk promoting breast cancer growth

Tumor hypoxia can be stable, or cyclic based on proximity to vasculature, and affects not just the cancer cells, but also other cells in the tumor microenvironment (TME). Although cyclic hypoxia can affect cells in the tumor microenvironment differently from stable hypoxia, its effect on non-malignant cells in the tumor microenvironment (TME) is unclear. Here, using single cell RNA ATAC sequencing of multicellular co-culture model of triple-negative breast cancer (TNBC), comprising MDA-MB-231 cells, fibroblasts (Fbs), mesenchymal stromal cells (MSCs), endothelial cells, and macrophages, we systemically map the transcriptomic response shaped by dynamic oxygen regimes. Cyclic hypoxia induced a distinct transcriptional program compared to stable hypoxia in a cell type specific manner, regulating cell subpopulation proportions with key phenotypic implications. In TNBC, cyclic hypoxia reversed chronic hypoxia-induced cell cycle arrest, and reversed the enrichment of a highly mesenchymal WNT5A+/COL6+ subpopulation stabilized in hypoxia. Furthermore, cyclic hypoxia increased fibroblast activation, but suppressed MSC proliferation. Mechanistically, cyclic hypoxia coordinated paracrine WNT5A/B-ROR1 signaling between fibroblasts and TNBCs. In a mouse breast CAF-TNBC co-xenograft model, disrupting this cyclic hypoxia driven WNT5A-ROR1 stroma-cancer crosstalk reduced tumor growth in vivo. Together, our findings highlight dynamics in oxygen regimen as distinct microenvironmental cues, reprograming the TME compartments to accelerate cancer growth and invasion.

cancer biology↗

bioRxiv2025

Identifying genes underlying parallel evolution of stromal resistance to placental and cancer invasion

Stromal regulation of cancer dissemination is now well recognized, however causal stromal genes and factors have yet not been identified. Placental invasion into endometrial stroma phenotypically is similar to cancer dissemination. There are also vast differences in the extent of placental invasion across mammals, with human pregnancies at the higher extreme end of invasiveness. We have previously demonstrated that epitheliochorial species, characterized by non-invasive placentation, have acquired stromal resistance to placental invasion, correlating with low cancer malignancy rates. Similarly, decidualization of human endometrial fibroblasts confers resistance to placental invasion. We hypothesized that both trajectories may convergently use similar pathways, using endometrial fibroblasts from 9 species to identify putative ELI-D1 genes underlying stromal vulnerability to invasion. ELI-D1 were negatively enriched in T1-T2 stage transition in many human cancers, typically preceding dissemination, bioinformatically validating their contribution to dissemination-preceding fibroblast activation in cancers. Finally, we have identified candidate transcriptional regulators underlying variation in ELI-D1 genes across eutherians, functionally showing that a key transcriptional regulator of ELI-D1 genes across species, Nr2f6, can regulate stromal resistance to invasion in human fibroblasts. Our comparative approach provides us with a putative, limited, gene-set linked to stromal vulnerability in human cancers, providing therapeutic opportunities to target cancer dissemination.

cancer biology↗

bioRxiv2024

Stable and Oscillatory Hypoxia Differentially Regulate Invasibility of Breast Cancer Associated Fibroblasts

As local regions in the tumor outstrip their oxygen supply, hypoxia can develop, affecting not only the cancer cells, but also other cells in the microenvironment, including cancer associated fibroblasts (CAFs). Hypoxia is also not necessarily stable over time, and can fluctuate or oscillate. Hypoxia Inducible Factor-1 is the master regulator of cellular response to hypoxia, and can also exhibit oscillations in its activity. To understand how stable, and fluctuating hypoxia influence breast CAFs, we measured changes in gene expression in CAFs in normoxia, hypoxia, and oscillatory hypoxia, as well as measured change in their capacity to resist, or assist breast cancer invasion. We show that hypoxia has a profound effect on breast CAFs causing activation of key pathways associated with fibroblast activation, but reduce myofibroblast activation and traction force generation. We also found that oscillatory hypoxia, while expectedly resulted in a "sub-hypoxic" response in gene expression, it resulted in specific activation of pathways associated with actin polymerization and actomyosin maturation. Using traction force microscopy, and a nanopatterned stromal invasion assay, we show that oscillatory hypoxia increases contractile force generation vs stable hypoxia, and increases heterogeneity in force generation response, while also additively enhancing invasibility of CAFs to MDA-MB-231 invasion. Our data show that stable and unstable hypoxia can regulate many mechnobiological characteristics of CAFs, and can contribute to transformation of CAFs to assist cancer dissemination and onset of metastasis.

cancer biology↗

bioRxiv2024

Oscillatory Hypoxia Induced Unfolded Protein Folding Response Gene Expression Predicts Low Survival in Human Breast Cancer Patients

Hypoxia is one of the key factors in the tumor microenvironment regulating nearly all steps in the metastatic cascade in many cancers, including in breast cancer. The hypoxic regions can however be dynamic with the availability of oxygen fluctuating or oscillating. The canonical response to hypoxia is relayed by transcription factor HIF-1, which is stabilized in hypoxia and acts as the master regulator of a large number of downstream genes. However, HIF-1 transcriptional activity can also fluctuate either due to unstable hypoxia, or by lactate mediated non-canonical degradation of HIF-1. Our understanding of how oscillatory hypoxia or HIF-1 activity specifically influence cancer malignancy is very limited. Here, using MDA-MB-231 cells as a model of triple negative breast cancer characterized by severe hypoxia, we measured the gene expression changes induced specifically by oscillatory hypoxia. We found that oscillatory hypoxia can specifically regulate gene expression differently, and at times opposite to stable hypoxia. Using The Cancer Genome Atlas (TCGA) RNAseq data of human cancer samples, we show that the oscillatory specific gene expression signature in MDA-MB-231 is enriched in most human cancers, and prognosticate low survival in breast cancer patients. In particular, we found that oscillatory hypoxia, unlike stable hypoxia, induces unfolded protein folding response (UPR) in cells resulting in gene expression predicting reduced survival.

cancer biology↗

bioRxiv2019

The Evolution of Placental Invasion and Cancer Metastasis are Causally Linked

Among mammals, the extent of placental invasion is correlated with vulnerability to malignancy. Animals with more invasive placentation (e.g. humans) are more vulnerable to malignancy, whereas animals with a non-invasive placenta (e.g. ruminants) are less likely to develop malignant cancer. To explain this correlation, we propose the hypothesis of Evolved Levels of Invasibility (ELI) positing that the permissiveness of stromal tissue to invasion is a unitary character affecting both placental and cancer invasion. We provide evidence for this hypothesis by contrasting invasion of human and bovine cancer and placental cells into a lawn of stromal cells from different species. We find that both bovine endometrial and skin fibroblasts are more resistant to invasion of placental and cancer cells than their human counterparts. Gene expression profiling identified genes with high expression in human but not bovine fibroblasts. Knocking down of a subset of them in human fibroblasts leads to significantly stronger resistance to cancer cell invasion. Comparative analysis of gene expression among mammals suggests that humans evolved higher vulnerability to malignancy than the eutherian ancestor, possibly as a correlate of more invasive placentation, and boroeutherians evolved to decrease stromal invasibility. Identifying the evolutionary determinants of stromal invasibility can provide significant insights to develop rational anti-metastatic therapeutics.

cancer biology↗