Thomas R. Cox, May 2019
Proteomic Profiling of Human Prostate Cancer-associated Fibroblasts (CAF) Reveals LOXL2-dependent Regulation of the Tumor Microenvironment
A new paper has just been published revealing the role of Lysyl Oxidase Like 2 (LOXL2) in the remodelling of the prostate cancer microenvironment. The work, carried out in collaboration with lead researchers from the Cancer Program, Biomedicine Discovery Institute at Monash University has just been published in Molecular and Cellular Proteomics.
In this paper we look at the differences between Normal Prostate Fibroblasts (NPFs) and prostate Cancer-Associated Fibroblasts (CAFs). We used quantitative mass-spectrometry based proteomics to determine which components of the ‘altered’ or reactive prostate cancer stroma are associated with poor patient prognosis. Our unique matched prostatic CAF and NPF approach to resolve key mediators of intercellular signaling within the tumor stroma identified LOXL2 as a critical mediator. We present the first data showing that the inhibition of LOXL2 in prostate CAFs can significantly perturb the prostate tumor microenvironment.
In prostate cancer, cancer-associated fibroblasts (CAF) exhibit contrasting biological properties to non-malignant prostate fibroblasts (NPF) and promote tumorigenesis. Resolving intercellular signaling pathways between CAF and prostate tumor epithelium may offer novel opportunities for research translation. To this end, the proteome and phosphoproteome of four pairs of patient-matched CAF and NPF were characterized to identify discriminating proteomic signatures. Samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a hyper reaction monitoring data-independent acquisition (HRM-DIA) workflow. Proteins that exhibited a significant increase in CAF versus NPF were enriched for the functional categories “cell adhesion” and the “extracellular matrix.” The CAF phosphoproteome exhibited enhanced phosphorylation of proteins associated with the “spliceosome” and “actin binding.” STRING analysis of the CAF proteome revealed a prominent interaction hub associated with collagen synthesis, modification, and signaling. It contained multiple collagens, including the fibrillar types COL1A1/2 and COL5A1; the receptor tyrosine kinase discoidin domain-containing receptor 2 (DDR2), a receptor for fibrillar collagens; and lysyl oxidase-like 2 (LOXL2), an enzyme that promotes collagen crosslinking. Increased activity and/or expression of LOXL2 and DDR2 in CAF were confirmed by enzymatic assays and Western blotting analyses. Pharmacological inhibition of CAF-derived LOXL2 perturbed extracellular matrix (ECM) organization and decreased CAF migration in a wound healing assay. Further, it significantly impaired the motility of co-cultured RWPE-2 prostate tumor epithelial cells. These results indicate that CAF-derived LOXL2 is an important mediator of intercellular communication within the prostate tumor microenvironment and is a potential therapeutic target.
Nguyen EV et al. Proteomic Profiling of Human Prostate Cancer-associated Fibroblasts (CAF) Reveals LOXL2-dependent Regulation of the Tumor Microenvironment.
Molecular and Cellular Proteomics (2019) | doi: 10.1074/mcp.RA119.001496
Cancer biomarker(s), Cancer-associated fibroblasts, Fibroblasts, LOXL2, Non-malignant prostate fibroblasts, Phosphoproteome, Prostate cancer, Prostate cancer biomarkers, Tumor microenvironment
Funding & Support
RJD, NLL, RAT, and GPR acknowledge grant support from Cancer Australia/Prostate Cancer Foundation of Australia (ID NCG2616). BAP was supported by the Australian Government Research Training Program (RTP) Scholarship. NLL was supported by a Strategic Grant Scheme (SGS16-0295). TRC and JNS are supported by the Cancer Institute NSW (171105) and National Health and Medical Research Council (NHMRC) (1140125). GPR was supported by the NHMRC Senior Principal Research Fellowship (1102752). RAT and MGL were supported by the Victorian Government through the Victorian Cancer Agency (VCA; Fellowships to RAT MCRF15023 and Fellowship to MGL MCRF18017). RJD was supported by a NHMRC Fellowship (1058540). Clinical data and patient follow up were kindly provided by the Melbourne Urological Research Alliance (MURAL) and biospecimens obtained from the Australian Prostate Cancer BioResource (APCB). The authors acknowledge the facilities, scientific and technical assistance of Monash Micro Imaging (MMI), Monash Biomedical Proteomics Facility and Flowcore, Monash University, Victoria, Australia. The authors acknowledge Jack Lonnborn for assistance with migration data analysis. The PXS-S2A compound was kindly supplied by Pharmaxis. The results published here are in part based upon data generated by the TCGA Research Network: http://cancergenome.nih.gov/.