Burks, H. E. | bioRxiv Science

bioRxiv2020

Th17-skewed inflammation due to genetic deficiency of a cadherin stress sensor

Desmoglein 1 (Dsg1) is a cadherin restricted to stratified tissues of terrestrial vertebrates, which serve as essential physical and immune barriers. Dsg1s importance in epidermal integrity is underscored by genetic, autoimmune and bacterial toxin-mediated disorders interfering with Dsg1 function. Dsg1 loss-of-function mutations in humans result not only in skin lesions, but also multiple allergies, and isolated patient keratinocytes exhibit increased pro-allergic cytokine expression. However, the mechanism by which genetic deficiency of Dsg1 causes chronic inflammation is unknown. To determine the systemic response to Dsg1 loss, we deleted the three tandem Dsg1 genes in mice using CRISPR/Cas9. Whole transcriptome analysis of E18.5 Dsg1-/- skin showed changes consistent with the observed aberrant differentiation and barrier impairment. Comparing epidermal transcriptomes from E18.5 Dsg1-deficient mice and humans with Dsg1 mutations revealed a shared psoriatic-like IL-17-skewed inflammatory signature and less so a pro-allergic IL-4/13 signature. Although the impaired intercellular adhesion observed in Dsg1-/- mice resembles that resulting from autoimmune anti-Dsg1 pemphigus foliaceus antibodies, transcriptomic analysis of pemphigus skin lesions lacks a prominent IL-17 signature. Thus, beyond impairing the physical barrier, chronic loss of Dsg1 function through gene mutation results in a psoriatic-like inflammatory signature before birth, possibly predisposing to skin inflammation.

immunology↗

bioRxiv2019

Evaluation of deacetylase inhibition in metaplastic breast carcinoma using multiple derivations of preclinical models of a new patient-derived tumor

Metaplastic breast carcinoma (MBC) is a clinically aggressive and rare subtype of breast cancer, with similar features to basal-like breast cancers. Due rapid growth rates and characteristic heterogeneity, MBC is often unresponsive to standard chemotherapies; and novel targeted therapeutic discovery is urgently needed. Histone deacetylase inhibitors (DACi) suppress tumor growth and metastasis through regulation of the epithelial-to-mesenchymal transition axis in various cancers, including basal-like breast cancers. We utilized a new MBC patient-derived xenograft (PDX) to examine the effect of DACi therapy on MBC. Cell morphology, cell cycle-associated gene expressions, transwell migration, and metastasis were evaluated in patient-derived cells and tumors after treatment with romidepsin and panobinostat. Derivations of our PDX model, including cells, spheres, organoids, explants, and in vivo implanted tumors were treated. Finally, we tested the effects of combining DACi with approved chemotherapeutics on relative cell biomass. DACi significantly suppressed the total number of lung metastasis in vivo using our PDX model, suggesting a role for DACi in preventing circulating tumor cells from seeding distal tissue sites. These data were supported by our findings that DACi reduced cell migration, populations, and expression of mesenchymal-associated genes. While DACi treatment did affect cell cycle-regulating genes in vitro, tumor growth was not affected compared to controls. Importantly, gene expression results varied depending on the cellular or tumor system used, emphasizing the importance of using multiple derivations of cancer models in preclinical therapeutic discovery research. Furthermore, DACi sensitized and produced a synergistic effect with approved oncology therapeutics on inherently resistant MBC. This study introduced a role for DACi in suppressing the migratory and mesenchymal phenotype of MBC cells through regulation of the epithelial-mesenchymal transition axis and suppression of the CTC population. Preliminary evidence that DACi treatment in combination with MEK1/2 inhibitors exerts a synergistic effect on MBC cells was also demonstrated.

cancer biology↗