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Background: Cancer cells have to take metabolic transformation in tumor progression when facing need of increased energy and adequate vascularization. However, molecular mechanism is not fully known. In this study, we showed that expression of carnitine palmitoyltransferase 1C (Cpt1c), as a member of the gate-keeper enzymes , which transferring long-chain fatty acids into mitochondria to further oxidation, which is regulated by AMPK promotes papillary thyroid carcinomas cells survival under metabolic stress conditions.Methods: Firstly, we used qRT-PCR to detect expression of Cpt1c in papillary thyroid carcinomas tissues compared with paired normal tissues. Secondly, to evaluate whether Cpt1c is induced under metabolic stress, models of hypoxia (0.2% oxygen) and glucose deprivation for cultured papillary thyroid carcinomas cells were established. Lastly, KTC-1 cells were treated with AICAR (as an agonist of AMPK) and Compound C (as an inhibitor of AMPK) to investigate the correlation of AMPK activity with Cpt1c expression under metabolic stress.Results: Cpt1c is higher in papillary thyroid carcinomas tissues compared with paired normal tissues. Furthermore, Cpt1c up-regulation promotes cancer cell growth and metastasis. In addition, the results showed that Cpt1c expression is induced by metabolic stress, including hypoxia and low glucose treatment. Consistently, Cpt1c can protect cells from cancer cells death caused by hypoxia and low glucose. Lastly, Cpt1c expression is regulated by AMPK activity.Conclusion: Here we describe that induction of Cpt1c expression facing metabolic stress in papillary thyroid carcinomas is at least partly regulated by AMPK activity and ultimately contribute to development and progression of papillary thyroid carcinomas.

The incidence of esophageal adenocarcinoma (EAC) is rising rapidly, and early detection within the precursor state of Barrett's esophagus (BE) is challenged by flat premalignant lesions that are difficult detect with conventional endoscopic surveillance. Overexpression of cell surface fibroblast growth factor receptor 2 (FGFR2) is an early event in progression of BE to EAC, and is a promising imaging target. We used phage display to identify the peptide SRRPASFRTARE that binds specifically to the extracellular domain of FGFR2. We labeled this peptide with a near-infrared fluorophore Cy5.5, and validated the specific binding to FGFR2 overexpressed in cells in vitro. We found high affinity kd = 68 nM and rapid binding k = 0.16 min−1 (6.2 min). In human esophageal specimens, we found significantly greater peptide binding to high-grade dysplasia (HGD) versus either BE or normal squamous epithelium, and good correlation with anti-FGFR2 antibody. We also observed significantly greater peptide binding to excised specimens of esophageal squamous cell carcinoma and gastric cancer compared to normal mucosa. These results demonstrate potential for this FGFR2 peptide to be used as a clinical imaging agent to guide tissue biopsy and improve methods for early detection of EAC and potentially other epithelial-derived cancers.

N‐Acetyl‐seryl‐aspartyl‐lysyl‐proline (Ac‐SDKP) is a critical negative regulator of fibrosis development in the liver. However, its extremely short half‐life in vivo greatly compromises its potential applications. Here, we report an Ac‐SDKP analog peptide with d‐amino acid replacement (Ac‐SDDKDP). The stability of Ac‐SDDKDP and its prevention of liver fibrosis were investigated in vitro and in vivo. The stabilities of Ac‐SDKP and Ac‐SDDKDP exposed to angiotensin‐1‐converting enzyme (ACE) and their half‐lives in rats and human sera were determined by high‐performance liquid chromatography. The inhibitory effects of Ac‐SDKP and Ac‐SDDKDP on the proliferation and activation of hepatic stellate cells (HSC‐T6) were evaluated using the Cell Counting Kit‐8, Western blotting, reverse transcription quantitative polymerase chain reaction, and immunofluorescence assays. Finally, the protective effects of Ac‐SDKP and Ac‐SDDKDP on carbon tetrachloride (CCl4)‐induced liver fibrosis in rats were compared. d‐Amino acid replacement significantly enhanced the stability of the peptide to ACE and prolonged the half‐life of Ac‐SDKP in rats and human sera. The Ac‐SDKP‐mediated inhibition of HSC‐T6 cell proliferation was well preserved, and Ac‐SDDKDP exerted inhibitory effects comparable to Ac‐SDKP on α‐smooth muscle actin (α‐SMA), collagen I and III expression, and phosphorylated‐Smad‐2 expression. After intraperitoneal (i.p.) administration, Ac‐SDDKDP exhibited significantly greater protection than Ac‐SDKP against CCl4‐induced liver fibrosis in rats. The serum alanine aminotransferase, aspartate aminotransferase, albumin, and total protein levels of the Ac‐SDDKDP‐treated rats were significantly lower than those of the Ac‐SDKP‐treated rats. α‐SMA, CD45, and collagen I and III expression, as well as Smad‐2 phosphorylation were significantly attenuated in the livers of the Ac‐SDDKDP‐treated rats compared to those of the Ac‐SDKP‐treated rats. Furthermore, we showed that the Ac‐SDDKDP concentration in the rat liver increased to a physiological level of 60 min after i.p. administration, although i.p. administration of Ac‐SDKP failed to enhance the peptide concentration in the rat liver. Our findings indicate that d‐amino acid replacement is a simple and effective method to enhance the stability of Ac‐SDKP. Ac‐SDDKDP represents potential application of Ac‐SDKP in fibrosis treatment and provides a new potential treatment strategy for liver fibrosis. © 2019 IUBMB Life, 71(9):1302–1312, 2019

Tumor targeting agents are being developed for early tumor detection and therapeutics. We previously identified the peptide SNFYMPL (SNF*) and demonstrated its specific binding to human esophageal specimens of high-grade dysplasia (HGD) and adenocarcinoma with imaging ex vivo. Here, we aim to identify the target for this peptide and investigate its potential applications in imaging and drug delivery. With SNF* conjugated affinity chromatography, mass spectrum, Western blot, enzyme-linked immunosorbent assay (ELISA), and molecular docking, we found that the epithelial cell adhesion molecule (EpCAM) was the potential target of SNF*. Next, we showed that FITC-labeled SNF* (SNF*-FITC) colocalized with EpCAM antibody on the surface of esophageal adenocarcinoma cells OE33, and SNF*-FITC binding patterns significantly changed after EpCAM knockdown or exogenous EpCAM transfection. With the data from TCGA, we demonstrated that EpCAM was overexpressed in 17 types of cancers. Using colon and gastric adenocarcinoma cells and tissues as examples, we found that SNF*-FITC bound in a pattern was colocalized with EpCAM antibody, and the SNF* binding did not upregulate the EpCAM downstream Wnt signals. Subsequently, we conjugated SNF* with our previously constructed poly­(histidine)-PEG/DSPE copolymer micelles. SNF* labeling significantly improved the micelle binding with colon and gastric adenocarcinoma cells in vitro, and enhanced the antitumor effects and decreased the toxicities of the micelles in vivo. In conclusion, we identified and validated SNF* as a specific peptide for EpCAM. The future potential use of SNF* peptide in multiple tumor surveillance and tumor-targeted therapeutics was demonstrated.