Biology subjects

Swiatnicki, M.

Publications and source records attributed to Swiatnicki, M..

4 recordsLinked to original sources

bioRxiv2024

Unravelling biological processess and EGFR pathway regulation by the receptor-like protein tyrosine phosphatase PTPRH in non-small cell lung cancer

The balance of protein phosphorylation is often disrupted in cancer, with hyperactivity of kinases and inactivation of phosphatases driving cell proliferation and survival pathways. PTPRH, a protein tyrosine phosphatase, is mutated in [~]5% of non-small cell lung cancers (NSCLC). However, how PTPRH contributes to biological processes and tumorigenesis was unknown. We uncovered PTPRHs candidate interactors and associated pathways by applying a proximity-dependent biotinylation assay (BioID) and generating a signature transcriptome in two NSCLC cell lines derived from the primary tumor (NCI-H23) or a metastatic site (NCI-H2023), followed by functional validation. Candidate interactors included signaling molecules and structural proteins linked to integrins and focal adhesions, adherens junctions, migration, and the cytoskeleton, in addition to interactions with the receptor tyrosine kinases EGFR, EPHA2, and ROR2, and the phosphatases PTPN3 and PTPRJ. Considering the importance of EGFR in lung cancers and the role of EPHA2 in regulating cell adhesion, we examined how PTPRH regulates their signaling. Overexpression of PTPRH decreased EGFR phosphorylation at tyrosine 1173. It also reduced phospho-EPHA2, with one of the target tyrosine residues identified as the ligand-dependent Y588. At the cellular level, PTPRH and EPHA2 colocalize, with PTPRH gain inducing morphological alterations, such as increased eccentricity, smaller size and changes in the cytoskeleton organization in NCI-H23 cells. These changes are accompanied by increased FAK Y397 phosphorylation, but reduced cell adhesion to the ECM. Additionally, pathway enrichment analysis revealed downregulation of multiple oncogenic, metabolic, and cell adhesion signaling pathways, with increased levels of PTPRH leading to reduced migration in vitro, suppressed tumor growth and lung colonization and tumor differentiation in vivo. Interestingly, some alterations may be independent of PTPRH catalytic activity and tailored to a cell lines site of origin and genetic background. These results indicate that PTPRH regulates key signaling, structural networks, and tumor behavior with loss facilitating NSCLC progression.

cancer biology↗

bioRxiv2021

Insight into mammary gland development and tumor prevention in a newly developed metastatic mouse model of breast cancer

The development of breast cancer has been observed due to altered regulation of mammary gland developmental processes. Thus, a better understand of the normal mammary gland development can reveal possible mechanism in how normal cells are re-programmed to become malignant cells. E2F1-4 are part of the E2F transcription factor family with varied roles in mammary development. However, little is known about the role of E2F5 in mammary gland development. A combination of scRNAseq and predictive signature tools demonstrate the presence of E2F5 in the mammary gland and showed altered activity during the various phases of mammary gland development and function. Testing the hypothesis that E2F5 regulates mammary function, we generated a mammary-specific E2F5 knockout mouse model, resulting in modest mammary gland development changes. However, after a prolonged latency the E2F5 conditional knockout mice developed highly metastatic mammary tumors with metastases in both the lung and liver. Transplantation of the tumors revealed metastases to lymph nodes that was enriched through serial transplantation. Through whole genome sequencing and RNAseq analysis we identified, and then confirmed in vivo, that Cyclin D1 was dysregulated in E2F5 conditional knockout mammary glands and tumors. Based on these findings, we propose that loss of E2F5 leads altered regulation of Cyclin D1, which facilitates the development of mammary tumors.

cancer biology↗

bioRxiv2019

Metastasis is altered through multiple processes regulated by the E2F1 transcription factor

The E2F family of transcription factors is important for many cellular processes, from their canonical role in cell cycle regulation to other roles in angiogenesis and metastasis. Alteration of the Rb/E2F pathway occurs in various forms of cancer, including breast cancer. E2F1 ablation has been shown to decrease metastasis in MMTV-Neu and MMTV-PyMT transgenic mouse models of breast cancer. Here we take a bioinformatic approach to determine the E2F1 regulated genomic alterations involved in the metastatic cascade, in both Neu and PyMT models. Through gene expression analysis, we reveal few transcriptome changes in non-metastatic E2F1-/- tumors relative to transgenic tumor controls. However investigation of these models through whole genome sequencing found numerous differences between the models, including differences in the proposed tumor etiology between E2F1-/- and E2F1+/+ tumors induced by Neu or PyMT. Investigating mutated genes through gene set analysis also found a significant number of genes mutated in the cell adhesion pathway in E2F1-/- tumors, indicating this may be a route for disruption of metastasis in E2F1-/- tumors. Overall, these findings illustrate the complicated nature of uncovering drivers of the metastatic process.

cancer biology↗

bioRxiv2018

Integrated sequence and gene expression analysis of mouse models of breast cancer reveals critical events with human parallels

Mouse models have an essential role in cancer research, yet little is known about how various models resemble human cancer at a genomic level. However, the shared genomic alterations in each model and corresponding human cancer are critical for translating findings in mice to the clinic. We have completed whole genome sequencing and transcriptome profiling of two widely used mouse models of breast cancer, MMTV-Neu and MMTV-PyMT. This genomic information was integrated with phenotypic data and CRISPR/Cas9 studies to understand the impact of key events on tumor biology. Despite the engineered initiating transgenic event in these mouse models, they contain similar copy number alterations, single nucleotide variants, and translocation events as human breast cancer. Through integrative in vitro and in vivo studies, we identified copy number alterations in key extracellular matrix proteins including Collagen 1 Type 1 alpha 1 (Col1a1) and Chondroadherin (CHAD) that drive metastasis in these mouse models. Importantly this amplification is also found in 25% of HER2+ human breast cancer and is associated with increased metastasis. In addition to copy number alterations, we observed a propensity of the tumors to modulate tyrosine kinase mediated signaling through mutation of phosphatases. Specifically, we found that 81% of MMTV-PyMT tumors have a mutation in the EGFR regulatory phosphatase, PTPRH. Mutation in PTPRH led to increased phospho-EGFR levels and decreased latency. Moreover, PTPRH mutations increased response to EGFR kinase inhibitors. Analogous PTPRH mutations are present in lung cancer patients and together this data suggests that a previously unidentified population of human lung cancer patients may respond to EGFR targeted therapy. These findings underscore the importance of understanding the complete genomic landscape of a mouse model and illustrate the utility this has in understanding human cancers.

cancer biology↗