Creation of Colonic Anastomosis in Mice

Intestinal anastomoses are commonly performed in both elective and emergent operations. Even so, anastomotic leaks are a highly feared complications of ...

University of Oklahoma Health Sciences Center

Docosahexaenoic acid (DHA) is a natural compound with anticancer and anti-angiogenesis activity that is currently under investigation as both a preventative agent and an adjuvant to breast cancer therapy. However, the precise mechanisms of DHA's anticancer activities are unclear. It is understood that the intercommunication between cancer cells and their microenvironment is essential to tumor angiogenesis. Exosomes are extracellular vesicles that are important mediators of intercellular communication and play a role in promoting angiogenesis. However, very little is known about the contribution of breast cancer exosomes to tumor angiogenesis or whether exosomes can mediate DHA's anticancer action.

Exosome-mediated microRNA signaling from breast cancer cells is altered by the anti-angiogenesis agent docosahexaenoic acid (DHA).

Platelet-derived growth factor (PDGF) acts through two conserved receptor tyrosine kinases: PDGFRα and PDGFRβ. Gain-of-function mutations in human  have been linked recently to genetic diseases characterized by connective tissue wasting (Penttinen syndrome) or overgrowth (Kosaki overgrowth syndrome), but it is unclear whether  mutations alone are responsible. Mice with constitutive PDGFRβ signaling caused by a kinase domain mutation (D849V) develop lethal autoinflammation. Here we used a genetic approach to investigate the mechanism of autoinflammation in  mice and test the hypothesis that signal transducer and activator of transcription 1 (STAT1) mediates this phenotype. We show that  mice with  knockout ( ) are rescued from autoinflammation and have improved life span compared with  mice. Furthermore, PDGFRβ-STAT1 signaling suppresses PDGFRβ itself. Thus,  fibroblasts exhibit increased PDGFRβ signaling, and mice develop progressive overgrowth, a distinct phenotype from the wasting seen in  mice. Deletion of interferon receptors ( or ) does not rescue wasting in  mice, indicating that interferons are not required for autoinflammation. These results provide functional evidence that elevated PDGFRβ signaling causes tissue wasting or overgrowth reminiscent of human genetic syndromes and that the STAT1 pathway is a crucial modulator of this phenotypic spectrum.

STAT1 modulates tissue wasting or overgrowth downstream from PDGFRβ.

Renal cell carcinoma (RCC) is a common and devastating disease characterized by a hypoxic microenvironment, epithelial-mesenchymal transition and potent resistance to therapy evidencing the presence of cancer stem cells (CSCs). Various CSC markers have been studied in RCC, but overall there is limited data on their role and most markers studied have been relatively nonspecific. Doublecortin-like kinase 1 (DCLK1) is a validated CSC marker in the gastrointestinal tract and evidence for an equivalent role in other cancers is accumulating. We used bioinformatics, immunohistochemistry, flow cytometry, spheroid self-renewal and chemoresistance assays in combination with overexpression and siRNA-knockdown to study the stem cell-supportive role of DCLK1 alternative splice variants (DCLK1 ASVs) in RCC. To target tumor cells expressing DCLK1 ASVs directly, we developed a novel monoclonal antibody (CBT-15) and delivered it systemically to RCC tumor xenografts. DCLK1 ASVs were overexpressed, enriched together with CSC markers and predictive of overall and recurrence-free survival in RCC patients. In vitro, DCLK1 ASVs were able to directly stimulate essential molecular and functional characteristics of renal CSCs including expression of aldehyde dehydrogenase, self-renewal and resistance to FDA-approved receptor tyrosine kinase and mTOR inhibitors, while targeted downregulation of DCLK1 reversed these characteristics. Finally, targeting DCLK1 ASV-positive cells with the novel CBT-15 monoclonal antibody blocked RCC tumorigenesis in vivo. These findings establish DCLK1 as a CSC marker with implications for therapy, disease progression and survival in RCC and demonstrate the therapeutic value of DCLK1-targeted monoclonal antibodies against renal CSCs.

Alternative splice variants of DCLK1 mark cancer stem cells, promote self-renewal and drug-resistance, and can be targeted to inhibit tumorigenesis in kidney cancer.

Article	Year
Exosome-mediated microRNA signaling from breast cancer cells is altered by the anti-angiogenesis agent docosahexaenoic acid (DHA). Molecular cancer\| PubMed ID: 26178901	2015
STAT1 modulates tissue wasting or overgrowth downstream from PDGFRβ. Genes & development\| PubMed ID: 28924035	2017
Alternative splice variants of DCLK1 mark cancer stem cells, promote self-renewal and drug-resistance, and can be targeted to inhibit tumorigenesis in kidney cancer. International journal of cancer\| PubMed ID: 29577277	2018

William L Berry

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