Single-cell transcriptome sequencing reveals heterogeneity of gastric cancer: progress and prospects.

Gastric cancer is one of the most serious malignant tumor and threatens the health of people worldwide. Its heterogeneity leaves many clinical problems unsolved. To treat it effectively, we need to explore its heterogeneity. Single-cell transcriptome sequencing, or single-cell RNA sequencing (scRNA-seq), reveals the complex biological composition and molecular characteristics of gastric cancer at the level of individual cells, which provides a new perspective for understanding the heterogeneity of gastric cancer. In this review, we first introduce the current procedure of scRNA-seq, and discuss the advantages and limitations of scRNA-seq. We then elaborate on the research carried out with scRNA-seq in gastric cancer in recent years, and describe how it reveals cell heterogeneity, the tumor microenvironment, oncogenesis and metastasis, as well as drug response in to gastric cancer, to facilitate early diagnosis, individualized therapy, and prognosis evaluation.

A comparative investigation of catalytic mechanism and domain between catechol-O-methyltransferase isoforms by isomeric shikonin and alkannin.

The differences in catalytic mechanism and domain between the soluble (S-COMT) and membrane-bound catechol-O-methyltransferase (MB-COMT) are poorly documented due to the unavailable crystal structure of MB-COMT. Considering the enzymatic nature of S-COMT and MB-COMT, the challenge could be solvable by probing the interactions between the enzymes with the ligands with minor differences in structures. Herein, isomeric shikonin and alkannin bearing a R/S -OH group in side chain at the C2 position were used for domain profiling of COMTs. Human and rat liver-derived COMTs showed the differences in inhibitory response (human's IC50 and Ki values for S-COMT < rat's, 5.80-19.56 vs. 19.56-37.47 µM; human's IC50 and Ki values for MB-COMT > rat's) and mechanism (uncompetition vs. noncompetition) towards the two isomers. The inhibition of the two isomers against human and rat S-COMTs was stronger than those for MB-COMTs (S-COMT's IC50 and Ki values < MB-COMT's, 5.80-37.47 vs. 40.01-111.8 µM). Additionally, the inhibition response of alkannin was higher than those of shikonin in no matter human and rat COMTs. Molecular docking stimulation was used for analysis. The inhibitory effects observed in in vitro and in silico tests were confirmed in vivo. These findings would facilitate further COMT-associated basic and applied research.

Sanguinarine inhibits melanoma invasion and migration by targeting the FAK/PI3K/AKT/mTOR signalling pathway.

CONTEXT: Sanguinarine (SAG) is the most abundant constituent of Macleaya cordata (Willd.) R. Br. (Popaceae). SAG has shown antimammary and colorectal metastatic effects in mice in vivo, suggesting its potential for cancer chemotherapy. OBJECTIVE: To determine the antimetastatic effect and underlying molecular mechanisms of SAG on melanoma. MATERIALS AND METHODS: CCK8 assay was used to determine the inhibition of SAG on the proliferation of A375 and A2058 cells. Network pharmacology analysis was applied to construct a compound-target network and select potential therapeutic targets of SAG against melanoma. Molecular docking simulation was conducted for further analysis of the selected targets. In vitro migration/invasion/western blot assay with 1, 1.5, 2 µM SAG and in vivo effect of 2, 4, 8 mg/kg SAG in xenotransplantation model in nude mice. RESULTS: The key targets of SAG treatment for melanoma were mainly enriched in PI3K-AKT pathway, and the binding energy of SAG to PI3K, AKT, and mTOR were -6.33, -6.31, and -6.07 kcal/mol, respectively. SAG treatment inhibited the proliferation, migration, and invasion ability of A375 and A2058 cells (p < 0.05) with IC50 values of 2.378 µM and 2.719 µM, respectively. It also decreased the phosphorylation levels of FAK, PI3K, AKT, mTOR and protein expression levels of MMP2 and ICAM-2. In the nude mouse xenograft model, 2, 4, 8 mg/kg SAG was shown to be effective in inhibiting tumour growth. CONCLUSIONS: Our research offered a theoretical foundation for the clinical antitumor properties of SAG, further suggesting its potential application in the clinic.

Stability of a binge drinking model with delay.

A more realistic binge drinking model with time delay is introduced. Time delay is used to represent the time lag of the immunity against drinking in our model. For the model without the time delay, using Routh-Hurwitz criterion, we obtain that the alcohol-free equilibrium is locally asymptotically stable if [Formula: see text]. We also obtain that the unique alcohol-present equilibrium is locally asymptotically stable if [Formula: see text]. For the model with time delay, the local stability of all the equilibria is derived. Furthermore, regardless of the time delay length, using comparison theorem and iteration technique, we obtain that the alcohol-free equilibrium is globally asymptotically stable under certain conditions. Numerical simulations are also conducted to illustrate and extend our analytic results.