We describe the characterization and purification of a protease that cleaves sterol regulatory element-binding protein-1 (SREBP-1) and SREBP-2 in vitro. Cleavage occurs between the basic helix-loop-helix-leucine zipper and the first transmembrane domain of each SREBP. This is the region in which the SREBPs are cleaved physiologically by a sterol-regulated protease that releases an NH2-terminal fragment that activates transcription of the genes for the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl CoA synthase. The cleavage enzyme, designated SREBP cleavage activity (SCA), belongs to a new class of cysteine proteases of the interleukin-1 beta-converting enzyme (ICE) family, all of which cleave at aspartic acid residues. Like ICE, SCA was inactive in cytosol, and it was activated in vitro by incubation at 30 degrees C. SCA was resistant to inhibitors of serine, aspartyl, and metalloproteases, but it was sensitive to N-ethylmaleimide. The enzyme cleaved SREBP-1 and SREBP-2 between the Asp and Ser of a conserved sequence (S/DEPDSP). The activity was blocked by a tetrapeptide aldehyde, Ac-Asp-Glu-Ala-Asp-aldehyde (Ac-DEAD-CHO). A purified preparation of SCA from hamster liver contained a prominent 20-kDa polypeptide that could be labeled with [14C]iodoacetic acid. Labeling was blocked by Ac-DEAD-CHO. Partial amino acid sequence of this polypeptide revealed that it was the hamster equivalent of human CPP32, a putative protease whose cDNA was recently identified by virtue of sequence homology to ICE. CPP32 and ICE have been implicated in apoptosis in animal cells. Whether SCA/CPP32 participates in vivo in the sterol-regulated activation of SREBP, or whether it activates SREBPs during apoptosis, remains to be determined.

Among its interests, the company has initiated various programs to produce vaccines for Plasmodium falciparum malaria and Plasmodium vivax malaria.

Epithelial-to-mesenchymal transition (EMT) is a major process to regulate cell migration and invasion. Inhibition of epidermal growth factor receptor (EGFR)-mediated EMT by tyrosine kinase inhibitors (TKIs) is a strategy to prevent lung cancer invasion. However, drug resistance is emerged and accelerated invasion through other signaling bypassing EGFR after TKIs therapy. c-Met signaling pathway is highly activated in EGFR-mutated lung cancer cells. Targeting c-Met signaling pathway may be a strategy to suppress EGFR-independent migration and invasion for lung cancer therapy. Therefore, we examined the anti-migration and anti-invasion abilities of shikonin, an active compound from Lithospermum erythrorhizon, in highly and ligand-induced c-Met activation lung cancer cells. Our results revealed that cell viability and cell cycle progression did not change under 1 μM of shikoinin treatment in highly c-Met expressive HCC827 lung cancer cells. Endogenous c-Met activation was dose-dependently inhibited and the migration and invasion activity of HCC827 cells were suppressed by shikonin treatment. Induction of E-cadherin expression and inhibition of vimentin, slug, and snail expression by shikonin was through c-Met-mediated PI3K/Akt and ERK signaling suppression. Furthermore, hepatocyte growth factor (HGF)-induced migration, invasion and EMT marker change were reversed by shikonin in low c-Met expressive A549 lung cancer cells. Inhibition of HGF-induced c-Met, PI3K/Akt and MEK/ERK activation were observed in shikonin-treated cells. Co-treatment of PI3K/Akt inhibitor or ERK inhibitor with shikonin enhanced shikonin-reversed HGF-regulated EMT marker expression. Taken together, the results suggested that the anti-migration and anti-invasion activities of shikonin was through c-Met inhibition and following by EMT suppression in lung cancer. J. Cell. Biochem. 118: 4639-4651, 2017. © 2017 Wiley Periodicals, Inc.

BackgroundAn increased number of emergency visits at the end of life may indicate poor-quality cancer care. The study aimed to investigate the prevalence and utilization of emergency visits and to explore the reasons for emergency department (ED) visits among cancer patients at the end of life.MethodsA retrospective cohort study was performed by tracking one year of ambulatory medical service records before death. Data were collected from the cancer dataset of Taiwan’s National Health Insurance Research Database (NHIRD).ResultsA total of 32,772 (19.2%) patients with malignant cancer visited EDs, and 23,883 patients died during the study period. Of these, the prevalence of emergency visits in the mortality group was 81.5%, and their ED utilization was significantly increased monthly to the end of life. The most frequent types of cancer were digestive and peritoneum cancers (34.8%), followed by breast cancer (17.7%) and head and neck cancers (13.3%). Older patients, males, and those diagnosed with metastases, respiratory or digestive cancer were more likely to use ED services at the end of life. Use of an ED service in the nearest community hospital to replace medical centers for dying cancer patients would be more acceptable in emergency situations.ConclusionsOur study provided population-based evidence related to ED utilization. An understanding of the reasons for such visits could be useful in preventing overuse of ED visits to improve the quality of end-of-life care.