20(S)-Protopanaxadiol (PPD) is one of the major active metabolites of ginseng. It has been reported that 20(S)-PPD shows a broad spectrum of antitumor effects. Our research study aims were to investigate whether apoptosis of human breast cancer MCF-7 cells could be induced by 20(S)-PPD by targeting the Phosphatidylinositol 3-kinase/Protein kinase B/Mammalian target of rapamycin (PI3K/AKT/mTOR) signal pathway in vitro and in vivo. Cell cycle analysis was performed by Propidium Iodide (PI) staining. To overexpress and knock down the expression of mTOR, pcDNA3.1-mTOR and mTOR small interfering RNA (siRNA) transient transfection assays were used, respectively. Cell viability and apoptosis were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-test and Annexin V /PI double-staining after transfection. The antitumor effect in vivo was determined by the nude mice xenograft assay. After 24 h of incubation, treatment with 20(S)-PPD could upregulate phosphorylated-Phosphatase and tensin homologue deleted on chromosome 10 (p-PTEN) expression and downregulate PI3K/AKT/mTOR-pathway protein expression. Moreover, G0/G1 cell cycle arrest in MCF-7 cells could be induced by 20(S)-PPD treatment at high concentrations. Furthermore, overexpression or knockdown of mTOR could inhibit or promote the apoptotic effects of 20(S)-PPD. In addition, tumor volumes were partially reduced by 20(S)-PPD at 100 mg/kg in a MCF-7 xenograft model. Immunohistochemical staining indicated a close relationship between the inhibition of tumor growth and the PI3K/AKT/mTOR signal pathway. PI3K/AKT/mTOR pathway-mediated apoptosis may be one of the potential mechanisms of 20(S)-PPD treatment.

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Ginsenoside-Rb3 (G-Rb3) has been previously demonstrated to attenuate myocardial ischemia-reperfusion injury (MIRI). The aim of the present study was to investigate this further and determine whether G-Rb3 protects the myocardium from ischemia-reperfusion injury via the inhibition of apoptosis. Adult male Sprague Dawley rats were randomly divided into four groups: Sham, MIRI, G-Rb3 treatment (orally, 20 mg/kg) and ischemic postconditioning (as the positive control). The drug or placebo treatment was administered to the rats once a day for three consecutive days, and MIRI was then induced by subjecting the rats to left anterior descending coronary artery ligation for 30 min and reperfusion for 2 h. The results showed that G-Rb3 treatment significantly reduced the number of apoptotic cells in the myocardium and the expression of B-cell lymphoma 2-associated X protein, and increased the expression of B-cell lymphoma 2. The activities of aspartate aminotransferase, lactate dehydrogenase and creatine kinase-MB in the serum were also reduced significantly by the G-Rb3 treatment. These findings suggest that G-Rb3 inhibits apoptosis in the early stage of MIRI, and attenuates MIRI when the reperfusion continues. G-Rb3 was also shown to significantly reduce the level of malondialdehyde and increase the activity of superoxide dismutase in the myocardium, which suggests that attenuating reactive oxygen species accumulation and oxidative stress may be the major mechanism underlying the anti-apoptotic effects of G-Rb3. The release of inflammatory factors was significantly attenuated by G-Rb3, which may also be associated with its anti-apoptotic effects.

There is an urgent need for a broad-spectrum and protective vaccine due to the emergence and rapid spreading of more contagious SARS-CoV-2 strains. We report the development of RBMRNA-176, a pseudouridine (Ψ) nucleoside-modified mRNA-LNP vaccine encoding pre-fusion stabilized trimeric SARS-CoV-2 spike protein ectodomain, and evaluate its immunogenicity and protection against virus challenge in mice and nonhuman primates. A prime-boost immunization with RBMRNA-176 at intervals of 21 days resulted in high IgG titers (over 1:819,000 endpoint dilution) and a CD4+ Th1-biased immune response in mice. RBMRNA-176 vaccination induced pseudovirus-neutralizing antibodies with IC50 ranging from 1:1020 to 1:2894 against SARS-CoV-2 spike pseudotyped wild-type and variant viruses, including Alpha, Beta, Gamma, and Kappa. Moreover, significant control of viral replication and histopathology in lungs was observed in vaccinated mice. In nonhuman primates, a boost given by RBMRNA-176 on day 21 after the prime induced a persistent and sustained IgG response. RBMRNA-176 vaccination also protected macaques against upper and lower respiratory tract infection, as well as lung injury. Altogether, these findings support RBMRNA-176 as a vaccine candidate for prevention of COVID-19.