Liujunzi decoction exerts potent antitumor activity in oesophageal squamous cell carcinoma by inhibiting miR-34a/STAT3/IL-6R feedback loop, and modifies antitumor immunity.

BACKGROUND: Liujunzi decoction (LJZD), a traditional herbal formula and one of the most commonly used adjuvant medications for the treatment of oesophageal squamous cell carcinoma (ESCC), exerts good antitumor and immunomodulatory activity. However, its specific mechanism of action remains largely unclear. PURPOSE: In order to examine the potential primary and adjuvant antitumor mechanisms of LJZD, both in vitro and in vivo. METHODS: IL-6 and miR-34a inhibitors were used to activate the miR-34a/STAT3/IL-6R feedback loop to observe the effects of LJZD. A humanised mouse model with a functional human immune system was constructed to evaluate the antitumor efficacy of LJZD in vivo on xenograft tumours, which was compared to that of the positive control drug anti-PD-1 monoclonal antibodies (mAb). Finally, a co-culture system of peripheral blood mononuclear and tumour cells in vitro was used to analyse the cytotoxic activity of LJZD on T cells. RESULTS: LJZD significantly interfered with IL-6-induced activation of the miR-34a/STAT3/IL-6R feedback loop in ESCC by restoring the expression of the tumour suppressor miR-34a, and inhibited the proliferation of EC109 oesophageal cancer cells in a dose-dependant manner. Furthermore, LJZD effectively suppressed oesophageal tumour growth in vivo and alleviated organ injury and visceral index. Furthermore, LJZD boosted antitumor immunity by increasing IFN-γ expression and CD8+tumour-infiltrating lymphocytes (TILs) infiltration in the peripheral blood and tumour tissues, respectively, which may be related to a decrease in PD-1, but not PD-L1 expression. Finally, we confirmed that LJZD strengthens the killing ability of T cells by suppressing PD-1 expression in a co-culture system in vitro. CONCLUSION: LJZD exerts excellent antitumor effect by interfering with the miR-34a/STAT3/IL-6R feedback loop and augmenting antitumor immune responses. Which provides new insights into mechanisms for LJZD and sheds light on the multifaceted role of phytomedicine in cancer.

[Polysaccharide of Atractylodis Macrocephalae Rhizoma inhibits expression of immune checkpoint PD-L1 by targeting miR-34a in esophageal carcinoma cells].

The immune checkpoint programmed cell death-ligand 1(PD-L1)-mediated immunosuppression is among the important features of tumor. PD-L1, an immunosuppressant, can induce T cell failure by binding to programmed cell death-1(PD-1). Thus, the key to restoring the function of T cells is inhibiting the expression of PD-L1. The Chinese medicinal Atractylodis Macrocephalae Rhizoma(AMR) has the anti-tumor, anti-inflammatory, antioxidant, and hypoglycemic activities, and the polysaccharide in AMR(PAMR) plays a crucial role in immunoregulation, but the influence on the immune checkpoints which are closely related to immunosuppression has not been reported. MicroRNA-34 a(miR-34 a) expression in esophageal carcinoma tissue is significantly lower than that in normal tissue. This study aims to investigate the inhibitory effect of PAMR on esophageal carcinoma cells, and the relationship between its inhibitory effect on PD-L1 expression and miR-34 a, which is expected to clarify the anti-tumor mechanism of PAMR. Firstly, different human esophageal carcinoma cell lines(EC9706, EC-1, TE-1, EC109 cells) were screend out, and expression of PD-L1 was determined. Then, EC109 cells, with high expression of PD-L1, were selected for further experiment. The result showed that PAMR suppressed EC109 cell growth. According to the real-time quantitative PCR(qPCR) and Western blot, it significantly suppressed the mRNA and protein expression of PD-L1, while promoting the expression of tumor suppressor miR-34 a. The confocal microscopy and luci-ferase assay proved that PAMR alleviated the inhibitory effect of PD-L1 while blocked miR-34 a. Additionally, the expression of PD-L1 was controlled by miR-34 a, and the combination of miR-34 a inhibitor with high-dose PAMR reversed the inhibitory effect of PAMR on PD-L1 protein expression. Thus, the PAMR may inhibit PD-L1 by increasing the expression of miR-34 a and regulating its downstream target genes. In conclusion, PAMR inhibits the expression of PD-L1 mainly by inducing miR-34 a.

Toosendanin Shows Potent Efficacy Against Human Ovarian Cancer through Caspase-Dependent Mitochondrial Apoptotic Pathway.

Toosendanin (TSN) is a triterpenoid extracted from the bark or fruits of Melia toosendan Sieb et Zucc, which is a traditional Chinese medicine and mainly grows in China and India. TSN has been verified to possess antitumor activities on various human cancers, whereas the effects of TSN on ovarian cancer (OC) has not been reported yet. Here, TSN was shown to significantly inhibit proliferation of SKOV3 and OVCAR3 cell lines in a dose- and time-dependent manner. Treatment of OC cells with TSN resulted in colony formation reduction, S and G2/M phase arrest, cell apoptosis, and dramatic decrease in mitochondrial membrane potential. Furthermore, TSN suppressed invasion and migration of OC cells. Research on molecular mechanism indicated that the above efficacy of TSN was associated with decreased expression of survivin, PARP-1, Bcl-2, Bcl-xl, caspase-3, caspase-9, MMP-2 and MMP-9 and increased expression of cleaved PARP-1, Bax, cleaved caspase-3 and cleaved caspase-9. Finally, in vivo results showed that TSN suppressed OC xenograft tumor growth by inducing apoptosis and regulating the related protein expression levels of SKOV3 cells in transplanted tumors. Taken together, our data provide new insights into TSN as a potentially effective reagent against human OC through caspase-dependent mitochondrial apoptotic pathway.