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Bloch, K.

Publications and source records attributed to Bloch, K..

2 recordsLinked to original sources

Lipidomic profiling of clinical prostate cancer reveals targetable alterations in lipid composition

Dysregulated lipid metabolism is a prominent feature of prostate cancer that is driven by androgen receptor (AR) signaling. Herein, we used quantitative mass spectrometry to define the "lipidome" in prostate tumors with matched benign tissues (n=21), independent tissues (n=47), and primary prostate explants cultured with a clinical AR antagonist, enzalutamide (n=43). Significant differences in lipid composition were detected and spatially visualized in tumors compared to matched benign samples. Notably, tumors featured higher proportions of monounsaturated lipids overall and elongated fatty acid chains in phosphatidylinositol and phosphatidylserine lipids. Significant associations between lipid profile and malignancy were validated in unmatched samples, and PL composition was characteristically altered in patient tissues that responded to AR inhibition. Importantly, targeting of altered tumor-related lipid features, via inhibition of acetyl CoA carboxylase 1, significantly reduced cellular proliferation in tissue explants (n=13). This first characterization of the prostate cancer lipidome in clinical tissues revealed enhanced fatty acid synthesis, elongation and desaturation as tumor-defining features, with potential for therapeutic targeting.

cancer biology↗

Endocytosis of very low-density lipoprotein particles: an unexpected mechanism for lipid acquisition by breast cancer cells

We previously described the expression of CD36 and lipoprotein lipase (LPL) by breast cancer (BC) cells and tissues, and the growth-promoting effect of very low-density lipoprotein (VLDL) supplementation observed in BC cell lines only in the presence of LPL. We now describe the deployment of LPL by BC cells. Our data support a model in which LPL is bound to a heparin-like heparan sulfate proteoglycan motif on the BC cell surface and acts in concert with the VLDL receptor to rapidly internalize intact lipoproteins via receptor-mediated endocytosis. We further observe substantial alterations in gene expression programs related to pathways for lipid acquisition (synthesis vs. uptake) in response to each the availability of exogenous triglyceride in tissue culture media and LPL expression status. Current literature emphasizes de novo fatty acid synthesis as the paramount mechanism for lipid acquisition by cancer cells. Our findings indicate that exogenous lipid uptake can serve as an important method of lipid acquisition for cancer cells, alongside de novo lipogenesis, and that the relative reliance on these two modes of lipid acquisition may vary among different BC cell lines and in response to nutrient availability. This concept has obvious implications for the development of therapies aimed at the lipid dependence of many different cancer types. Moreover, the mechanism that we have elucidated provides a direct connection between dietary fat and tumor biology.

cancer biology↗