Cinnamaldehyde inhibits cytokine storms induced by the ORF3a protein of SARS-CoV-2 via ROS-elimination in activated T cells.

Cytokine storms are the cause of complications in patients with severe COVID-19, and it becomes the target of therapy. Several natural compounds were selected to screen the inhibitory effect on T-cell proliferation by Fluorescence-Activated Cell Sorting (FACS) and cytokine production by enzyme-linked immunosorbent assay (ELISA). Open reading frame 3a (ORF3a) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulates the specific T-cell activation model in vivo and in vitro. The coculture system included the macrophage cell line RAW264.7 and splenocytes. Reactive oxygen species (ROS) levels and glycolysis in T cells were evaluated. Cinnamaldehyde effectively inhibits cytokine storms both in vitro and in vivo. It decreased inflammatory cytokine (such as IFN-γ, TNF-α, IL-6, and IL-2) production by murine peripheral blood cells upon direct stimulation with ConA, after immunization with the MHV-A59 virus or ORF3a peptide from SARS-CoV-2. Cinnamaldehyde restored the percentage of T cells, which was originally decreased in the peripheral blood and splenocytes of ORF3a-immunized mice. In a coculture system, cinnamaldehyde reduced the secretion of inflammatory cytokines from macrophages in a T-cell dependent manner. Furthermore, cinnamaldehyde decreased the ROS level in activated T cells, which in turn reduced glycolysis and the activation of T cells. Cinnamaldehyde can be used as a candidate molecule for COVID-19.

An Asparagus polysaccharide fraction inhibits MDSCs by inducing apoptosis through toll-like receptor 4.

Despite decades of research, malignant tumors are extremely difficult to eliminate with conventional methods. Although surgical resection potentially eradicates the problem, only a few cases are suitable for operation, and other approaches often involve harmful consequences. Revolutionary methods are desperately needed to improve patient outcomes and diminish harmful side effects. Myeloid-derived suppressor cells (MDSCs), downregulators of the innate and adaptive immune systems, have been widely studied over the past 2 decades. MDSCs inhibit the antitumor immune response by suppressing T cell proliferation, cytokine production, and tumor cell killing. With MDSCs becoming novel targets in cancer therapy, our research has focused on the anti-MDSC function of Asparagus polysaccharide (AP), extracted from asparagus, a traditional Chinese herb. In this study, we have used MDSCs isolated from the spleen of mice with colon cancer as an in vitro model to assess the efficacy of AP. Treatment of MDSCs with AP significantly decreased cell proliferation and induced apoptotic cell death through a toll-like receptor 4 dependent way. Subsequent studies showed that the AP treatment enhanced the expression of Bax and Caspase-9 and inhibited the expression of Bcl-2, suggesting that AP induced apoptosis in the MDSCs via the intrinsic pathway. Altogether, the results showed that AP exhibited a significant anti-MDSC activity and attenuated suppression of the antitumor immune response, thereby indicating its potential use in cancer therapy.

Polysaccharides from Polygonatum Inhibit the Proliferation of Prostate Cancer-Associated Fibroblasts.

Inhibition of cancer-associated broblasts (CAFs) may improve the efficacy of cancer therapy. Polysaccharide extracted from polygonatum can selectively inhibit the growth of prostate-CAFs (<.001) without inhibiting the growth of normal broblasts (NAFs). Polysaccharides from polygonatum stimulate autophagy of prostate-CAFs. 3-methyl-adenine(3-MA) is an autophagy inhibitor. 3-MA was added to prostate-CAFs with polysaccharide from polygonatum to determine whether autophagy plays an important role in the restrained effect. Finally, polysaccharide from polygonatum treatment significantly increased the activation of Beclin-1 and LC3, key autophagy proteins. Polysaccharides from polygonatum stimulate autophagy of prostate-CAFs and inhibits prostate-CAF growth, indicating that a novel anti-cancer strategy involves inhibiting the growth of prostate- CAFs.

DH332, a synthetic ß-carboline alkaloid, inhibits B cell lymphoma growth by activation of the caspase family.

AIM: The purpose of this study was to investigate anti-tumor effects and safety of DH332, a new ß-carboline alkaloids derivatives in vitro and in vivo. MATERIALS AND METHODS: The effects of DH332 on human (RAMOS RA.1) and mouse (J558) B lymphoma cell lines were detected using a CCK-8 kit (Cell Counting Kit-8), and apoptosis was detected by flow cytometry with PI/annexinV staining. Western blotting was used to detected caspase-3 and caspase-8. Neurotoxic and anti-tumor effects were evaluated in animal experiments. RESULTS: DH332 exerts a lower neurotoxicity compared with harmine. It also possesses strong antitumor effects against two B cell lymphoma cell lines with low IC50s. Moreover, DH332 could inhibit the proliferation and induce the apoptosis of RAMOS RA.1 and J558 cell lines in a dose-dependent manner. Our results suggest that DH332 triggers apoptosis by mainly activating the caspase signaling pathway. In vivo studies of tumor-bearing BALB/c mice showed that DH332 significantly inhibited growth of J558 xenograft tumors. CONCLUSIONS: DH332 exerts effective antitumor activity in vitro and in vivo, and has the potential to be a promising drug candidate for lymphoma therapy.

A myeloid cell population induced by Freund adjuvant suppresses T-cell-mediated antitumor immunity.

Although adjuvants are important components of vaccines, few studies have been conducted to establish the criteria on adjuvant selection and to investigate mechanisms of adjuvant actions during vaccination. Here we found that complete Freund adjuvant (CFA) induced a CD11b cell population in a B-cell independent manner. This cell population exhibited strong ability to inhibit T-cell-mediated rejection of tumor transplants. In vitro studies indicated that these cells induced T-cell apoptosis and down-regulated interferon-gamma production. Nitric oxide (NO) played important roles to achieve these effects. Plenty of NO was produced by these CFA-induced CD11b cells. The addition of N-nitro-L-arginine-methyl ester, an inhibitor of NO synthase, rescued T cells from apoptosis and partially abrogated the detrimental effects of CFA in cancer vaccines. Incomplete Freund adjuvant, one of the adjuvants still being used in clinical trials, also induced a similar cell population. Our results reveal a previously unknown mechanism in which the myeloid cell population induced by Freund adjuvant impairs antitumor immunity, and highlight the importance of adjuvant selection during tumor vaccination.

[Relationships between tumor shrinkage and peripheral blood cell changes during tumor-rejection induced by a high dose of 5-FU in C57BL/6 mice].

AIM: To investigate the relationship between the alterations of complete blood counts and tumor shrinkage during tumor rejection induced by a high dose of 5-FU in C57BL/6 mice. METHODS: Wild type C57BL/6 tumor-bearing mice were treated with different doses of 5-FU intraperitoneally. 75 mg/kg 5-FU was the minimal effective dose of 5-FU that could cure the tumor-bearing mice. Then another 6 tumor-bearing mice were treated intraperitoneally with 5-FU (75 mg/kg). Blood samples were obtained from orbital venous sinus on different days before and after 5-FU treatment, and then complete blood counts were performed and the relationship between the alterations of blood counts and tumor shrinkage after 5-FU treatment was analyzed. RESULTS: Tumor sizes decreased steadily and tumors disappeared within the first week after 5-FU treatment; and at the same time 75 mg/kg 5-FU also had side effects on peripherial blood cells. The number of WBC significantly decreased from the first day after 5-FU treatment (P<0.001). But during the 7 th to 15 th day the number of WBC rebounced back to normal level (P>0.05). Later it decreased again and it couldn't recover back to normal level at the 28th day after 5-FU treatment (P<0.01). The concentration of Hb decreased at the first day and lasted for 2 weeks (P<0.01). It increased gradually back to normal in 2 weeks after 5-FU treatment. The inhibitory effect of 5-FU on platelets count was not obvious. The platelet count increased significantly at the first and at the 11th day after 5-FU treatment respectively (P<0.01). CONCLUSION: Tumor shrinkage after 5-FU treatment is not related to the decreased number of WBC or RBC, but correlated with the increased number of platelet at the first day after 5-FU treatment.