The Apoptosis Repressor with a CARD Domain (ARC) Gene Is a Direct Hypoxia-Inducible Factor 1 Target Gene and Promotes Survival and Proliferation of VHL-Deficient Renal Cancer Cells

Triple-negative breast cancer (TNBC) is notoriously aggressive with high metastatic potential, which has recently been linked to high rates of fatty acid oxidation (FAO). Here we report the mechanism of lipid metabolism dysregulation in TNBC through the prometastatic protein, CUB-domain containing protein 1 (CDCP1). We show that a "low-lipid" phenotype is characteristic of breast cancer cells compared with normal breast epithelial cells and negatively correlates with invasiveness in 3D culture. Using coherent anti-Stokes Raman scattering and two-photon excited fluorescence microscopy, we show that CDCP1 depletes lipids from cytoplasmic lipid droplets (LDs) through reduced acyl-CoA production and increased lipid utilization in the mitochondria through FAO, fueling oxidative phosphorylation. These findings are supported by CDCP1's interaction with and inhibition of acyl CoA-synthetase ligase (ACSL) activity. Importantly, CDCP1 knockdown increases LD abundance and reduces TNBC 2D migration in vitro, which can be partially rescued by the ACSL inhibitor, Triacsin C. Furthermore, CDCP1 knockdown reduced 3D invasion, which can be rescued by ACSL3 co-knockdown. In vivo, inhibiting CDCP1 activity with an engineered blocking fragment (extracellular portion of cleaved CDCP1) lead to increased LD abundance in primary tumors, decreased metastasis, and increased ACSL activity in two animal models of TNBC. Finally, TNBC lung metastases have lower LD abundance than their corresponding primary tumors, indicating that LD abundance in primary tumor might serve as a prognostic marker for metastatic potential. Our studies have important implications for the development of TNBC therapeutics to specifically block CDCP1-driven FAO and oxidative phosphorylation, which contribute to TNBC migration and metastasis.he transmembrane glycoprotein, CUB-domain containing protein 1 (CDCP1), is a driver of migration and invasion in multiple forms of carcinoma, including renal (1, 2), ovarian (3, 4), prostate (5), pancreatic (6, 7), colon (8-12), and triple-negative breast (TNBC) (13, 14) carcinomas, among others. Furthermore, CDCP1's role in tumor metastasis was confirmed in vivo in lung (15, 16), ovarian (17), prostate (5), and colon (9) cancers. Although CDCP1's role in TNBC metastasis has not been established to date, high CDCP1 expression has been validated as a prognostic marker of poor survival in TNBC when combined with positive node status (18).Our understanding of CDCP1's upstream regulators, its mechanism of activation, and downstream signaling continues to expand (recently reviewed in ref. 19). Studies by others (5) and our group (14) have demonstrated that CDCP1 cleavage is necessary for its activation, and recently, we have further shown that cleavage stimulates CDCP1 homodimerization (14). Homodimeric CDCP1 stimulates phosphorylation of protein kinase C δ (PKCδ) by Src kinase, leading to migration and invasion of TNBC cells in vitro (14). Adding to our knowledge of CDCP1's downstream signaling, we report that CDCP1 regulates lipid m...

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“…The Western blotting protocol was adapted from Razorenova et al (79). Forty micrograms of protein were used per lane.…”

Section: Methodsmentioning

confidence: 99%

CDCP1 drives triple-negative breast cancer metastasis through reduction of lipid-droplet abundance and stimulation of fatty acid oxidation

Wright

Hou

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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148

102

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“…TRIM32 short hairpin RNA (shRNA) (target sequence: 5′‐GGUGGAAAGCUUUGGUGUU‐3′) was cloned into the pLKO.1 vector. Lentiviral particle production was performed according to other reports 14. Cells were infected with recombinant lentivirus‐transducing units plus 5 mg/mL Polybrene (Sigma, St Louis, MO, USA).…”

Section: Methodsmentioning

confidence: 99%

TRIM32 promotes cell proliferation and invasion by activating β‐catenin signalling in gastric cancer

Wang

et al. 2018

J Cellular Molecular Medi

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The tripartite motif (TRIM) family comprises more than 70 members involved in the regulation of many cellular pathways. TRIM32 acts as an E3 ubiquitin ligase and has been reported to participate in many human cancers. Here, we aimed to investigate the role of TRIM32 in gastric cancer (GC) and the clinical implications. High expression of TRIM32 was observed in GC tissues and cell lines, and was significantly associated with poor prognosis. Knockdown TRIM32 expression remarkably suppressed the proliferation, migration, and invasion of GC cells in vitro and tumour growth in vivo, whereas overexpression of TRIM32 yielded the opposite results. Western blotting and quantitative reverse‐transcription PCR (qRT‐PCR) analyses revealed that up‐regulation of TRIM32 significantly enhanced expression of β‐catenin protein and of its downstream targets TCF1, cyclin D1, Axin2 and MMP7 mRNAs. Moreover, we found that the mechanism behind the TRIM32‐promoted GC progression was related to the β‐catenin signalling pathway. Collectively, these data suggest that TRIM32 promotes GC cell proliferation, migration, and invasion by activating the β‐catenin signalling pathway.

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“…Under normoxic conditions, HIF-1a subunits are modified by prolyl hydroxylase, which leads to VHL tumor suppressor gene-mediated proteosomal degradation. Several recent studies have indicated that VHL loss enhances HIF-1a expression, thereby promoting cancer cell proliferation and survival [22]. Therefore, further study of the relationship between transcriptional levels of VHL and B7eH4 would be instructive.…”

Section: Discussionmentioning

confidence: 99%

Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

Jeon

Park

Choi

et al. 2015

Biochemical and Biophysical Research Communications

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The Apoptosis Repressor with a CARD Domain (ARC) Gene Is a Direct Hypoxia-Inducible Factor 1 Target Gene and Promotes Survival and Proliferation of VHL-Deficient Renal Cancer Cells

Cited by 33 publications

References 53 publications

CDCP1 drives triple-negative breast cancer metastasis through reduction of lipid-droplet abundance and stimulation of fatty acid oxidation

CDCP1 drives triple-negative breast cancer metastasis through reduction of lipid-droplet abundance and stimulation of fatty acid oxidation

TRIM32 promotes cell proliferation and invasion by activating β‐catenin signalling in gastric cancer

Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

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