Anti-Acat1 polyclonal antibody

Prostate cancer is the most common malignancy and the second leading cause of cancer-related deaths in men. One common treatment is androgen-deprivation therapy, which reduces symptoms in most patients. However, over time, patients develop tumors that are androgen-independent and ultimately fatal. The mechanisms that cause this transition remain largely unknown, and as a result, there are no effective treatments against androgen-independent prostate cancer. As a model platform, we used the LNCaP cell line and its androgen-independent derivative, LNCaP-SF. Utilizing stable isotope labeling with amino acids in cell culture coupled to mass spectrometry, we assessed the differential global protein expression of the two cell lines. Our proteomic analysis resulted in the quantification of 3355 proteins. Bioinformatic prioritization resulted in 42 up-regulated and 46 down-regulated proteins in LNCaP-SF cells relative to LNCaP cells. Our top candidate, HMGCS2, an enzyme involved in ketogenesis, was found to be 9-fold elevated in LNCaP-SF cells, based on peptide ratios. After analyzing the remaining enzymes of this pathway (ACAT1, BDH1, HMGCL, and OXCT1), we observed increased expression of these proteins in the LNCaP-SF cells, which was further verified using Western blotting. To determine whether these enzymes were up-regulated in clinical samples, we performed quantitative PCR and immunohistochemistry on human prostate cancer tissues, from which we observed significantly increased transcript and protein levels in high-grade cancer (Gleason grade >= 8). In addition, we observed significant elevation of these enzymes in the LuCaP 96AI castration-resistant xenograft. Further assessment of ACAT1 on human castration-resistant metastatic prostate cancer tissues revealed substantially elevated expression of ACAT1 in these specimens. Taken together, our results indicate that enzymes of the ketogenic pathway are up-regulated in high-grade prostate cancer and could serve as potential tissue biomarkers for the diagnosis or prognosis of high-grade disease.

Metabolic alteration for adaptation of the local environment has been recognized as a hallmark of cancer. GNPAT dysregulation has been implicated in hepatocellular carcinoma (HCC). However, the precise posttranslational regulation of GNPAT is still undiscovered. Here we show that ACAT1 is upregulated in response to extra palmitic acid (PA). ACAT1 acetylates GNPAT at K128, which represses TRIM21-mediated GNPAT ubiquitination and degradation. Conversely, GNPAT deacetylation by SIRT4 antagonizes ACAT1's function. GNPAT represses TRIM21-mediated FASN degradation and promotes lipid metabolism. Furthermore, shRNA-mediated ACAT1 ablation and acetylation deficiency of GNPAT repress lipid metabolism and tumor progression in xenograft and DEN/CCl4-induced HCC. Otherwise, ACAT1 inhibitor combination with sorafenib enormously retards tumor formation in mice. Collectively, we demonstrate that stabilization of FASN by ACAT1-mediated GNPAT acetylation plays a critical role in hepatocarcinogenesis.