Wanqi Zhou

Development of a selective S1P1 receptor agonist, Syl930, as a potential therapeutic agent for autoimmune encephalitis

Sphingosine-1-phosphate receptor subtype 1 (S1P1) is essential for lymphocyte egress from secondary lymphoid organs and is a validated drug target for the treatment of autoimmune disorders. However, during the preclinical and clinical trials of S1P1 modulators, the undesired activation of S1P3, a subtype of sphingosine 1-phosphate (S1P) receptors family, by S1P1 modulators often results in bradycardia in patients. Thus, we designed and synthesized a new series of selective S1P1 agonists. One of them, Syl930 (the prodrug), is preference to activate S1P1 but not S1P3. In this study, we further investigated the therapeutic potential of Syl930 on an experimental autoimmune encephalomyelitis (EAE) model in Lewis rats. We found that Syl930 can activate and internalize S1P1 receptors and effectively decreased the periphery blood lymphocytes (PBL) in SD rats, and subsequently rendered PBL insensitive to egress signal from secondary lymphoid organs (SLO). Intriguingly, the treatment of Syl930 did not bring any side effect on heart rate of the tested rats. Furthermore, the suppressed PBL caused by Syl930 was able to recover within 3 days after the last dose of treatment, which is correlated to the relatively short elimination half-life of Syl930. In the rat EAE model, therapeutic treatment with Syl930 significantly inhibited the progression of EAE and EAE-associated histological changes in brain and spinal cord of Lewis rats. These results illustrate that, as a selective S1P1 agonist, Syl930 exhibits a profound and rapidly reversible suppression of lymphocyte trafficking and it has the potential to serve as a therapeutic agent for autoimmune encephalitis.

Design, synthesis and docking-based 3D-QSAR study of novel 2-substituted 2-aminopropane-1,3-diols as potent and selective agonists of sphingosine-1-phosphate 1 (S1P1) receptor

Spingosine-1-phosphate receptor 1 (S1P1) has been actively pursued as an important therapeutic target in immune regulation. A series of 2-substituted 2-aminopropane-1,3-diols were designed and synthesized as selective S1P1 agonists. Most of the compounds with a biphenyl ether scaffold showed moderate to excellent S1P1/S1P3 selectivity. Compound 40c is identified as a potent S1P1 agonist with 350-fold S1P1/S1P3 selectivity. 39c, the alcohol form of 40c exerted good lymphopenia activity in vivo but with weak influence on heart rate. To investigate the SARs of 2-substituted 2-aminopropane-1,3-diols in more details, COMFA (q2 = 0.547, r2 = 0.986) and COMSIA (q2 = 0.544, r2 = 0.943) models were established based on molecular docking alignment, which were validated with high reliability in predicting activities of agonists. The 3D-QSAR models will be helpful in the design of novel, potent and selective S1P1 agonists.

The novel anti-neuroblastoma agent PF403, inhibits proliferation and invasion in vitro and in brain xenografts

Neuroblastoma is the most common cancer in infants and the fourth most common cancer in children. Our previous study showed that PF403 had a potent antitumor ability. In the present study, we evaluated the anti-neuroblastoma property of PF403 and investigated the underlying mechanisms. MTT assay, colony formation assay and flow cytometry assay were used to assess cytotoxicity of PF403 on SH-SY5Y cells. Transwell assay was chosen to estimate the anti-invasion ability of PF403 on neuroblastoma cells. The protein expression was detected by western blot analysis. The SH-SY5Y brain xenograft model was used to assess in vivo antitumor activity of PF403. PF403-mediated SH-SY5Y cell death was found to be dose- and time-dependent, and PF403 was able to limit invasion and metastasis of neuroblastoma cells. MRI and pathology analysis proved that the pro-drug of PF403, CAT3, inhibited SH-SY5Y cells in vivo. PF403 decreased expression of phosphorylated FAK, MMP-2 and MMP-9 proteins, and downregulated the activity of PI3K/AKT and Raf/ERK pathways, followed by regulation of the proteins expression of Bcl-2 family, activated caspase-3, -9 and PARP and initiation of apoptosis of neuroblastoma cells. PF403 exerted cytotoxicity against SH-SY5Y neuroblastoma cell both in vitro and in vivo, and inhibited its invasion ability, suggesting PF403 has potential as a new anticancer drug for the treatment of neuroblastoma.

The study of a novel sorafenib derivative HLC-080 as an antitumor agent.

In this study, our objective is to evaluate the potential of a novel Sorafenib derivative, named HLC-080, as a new anticancer agent for colon cancer. We firstly carried out MTT assay, colony formation assay, flow cytometry analysis and transwell invasion assay to determine effect of our compound HLC-080 on cell viability, anti-proliferation activity, cell cycle arrest and the intervention on cell invasion, respectively. On the other hand, in vivo antitumor activity of HLC-080 was also tested using H22 xenograft model and the angiogenesis effect of HLC-080 was measured by EA.hy926 tube formation assay. The expression levels of various proteins in HLC-080 treated with HT-29 cell lines were examined using Western blot and ELISA experiments. The results showed that HLC-080 could dramatically inhibit the growth and colony formation of various tumor cells, therefore exhibited remarkable antitumor activity. HLC-080 can induce cell cycle arrest at G1 phase in HT-29 cells and subsequently inhibit the invasive potential of colon cancer cells. HLC-080 also exhibits anti-angiogenesis effect in EA.hy926 model. Additionally, the in vivo study showed that HLC-080 was able to reduced the tumor weight with the rate of 35.81%. And at the concentration of 0.352±0.034 µM, HLC-080 is able to reduce half of the regular protein level of p-c-Raf (Ser259), consequently block Raf/MEK/ERK signaling in HT-29 cell lines. In conclusion, our study suggests that Sorafenib derivative HLC-080 has the potential to inhibit cell proliferation and angiogenesis, Since, HLC-080 is particularly active against human colon cancer cells, our study highlights that HLC-080 and its related analogues may serve as a new anti-cancer drug, particularly against colon cancer.

Silencing Aurora A leads to re-sensitization of breast cancer cells to Taxol through downregulation of SRC-mediated ERK and mTOR pathways

While Taxol has been reported to improve the clinical survival of breast cancer patients, subsequently developed drug-resistance of the cancer cells limits its final efficacy and applications. Previous studies suggested that Aurora A is involved in the development of the Taxol-resistance of breast cancer. We established Taxol-resistant breast cancer MCF-7/T cells and xenograft models to explore the role of Aurora A in Taxol resistant ER-positive breast cancer. Compared with their parental MCF-7/C cells, the Taxol-resistant MCF-7/T cells exhibited enhanced colony formation, less cell death and higher invasive ability. The resistant cells presented overexpressed Aurora A, elevated phosphorylated SRC and upregulated Ras/Raf/ERK and Akt/mTOR pathways. Silencing of Aurora A reduced the activity of SRC and downregulated the ERK and Akt/mTOR pathways, which led to re-sensitization of the resistant MCF-7/T cells to Taxol in vitro. These results suggested that the activation of Aurora A and the subsequent upregulation of ERK and Akt through SRC induced Taxol-resistance in breast cancer cells, and inhibiting Aurora A and the related SRC/EKT/Akt pathway could restore the sensitivity of breast cancer cells to Taxol. These results might shed light on the development of strategies to circumvent Taxol-related chemoresistance in breast cancer clinical practice.

The molecular mechanisms of a novel multi-kinase inhibitor ZLJ33 in suppressing pancreatic cancer growth.

ZLJ33, an oral active multi-kinase inhibitor, was evaluated both in vitro and in vivo against human pancreatic cancer. It could effectively inhibit cell proliferation, induce apoptosis, and cause inhibition of invasion in pancreatic cancer cells. At a dose of 15.0 mg/kg, ZLJ33 induced tumor shrink in Mia-PaCa2, Capan2, and AsPC-1 xenografts models by 60.59%, 74.19%, and 71.54% according to the tumor weight, respectively. The effect of ZLJ33 on pancreatic cancer was mainly mediated by inactivation of p-PDGFRβ, p-c-Raf, and p-RET. Treatment with ZLJ33 did not cause side effect of hematology indexes in the pancreatic cancer xenograft model. ZLJ33 could be a potential therapeutic agent against pancreatic cancer.