Functional Role of Glycosphingolipids in Cancer.

Glycosphingolipids (GSLs) are ubiquitous components on animal cell membranes, and exposed on the outer surface. Various studies have demonstrated that they play key roles in cell proliferation, adhesion, motility and differentiation. Usually, the specific types of GSLs are expressed more highly in tumors than in normal tissues, which are known as tumorassociated antigens. It has been revealed that most tumor cells show altered GSLs patterns on their surface, abnormal GSLs signaling and biosynthesis, which together play a major role in tumor development. Tumor-associated GSL antigens have been used in the development of antitumor vaccines. There is no doubt that GSLs play a crucial role in tumor progression and would be a promising target for cancer treatment.

Chemoenzymatic synthesis of arabinomannan (AM) glycoconjugates as potential vaccines for tuberculosis.

Mycobacteria infection resulting in tuberculosis (TB) is one of the top ten leading causes of death worldwide in 2018, and lipoarabinomannan (LAM) has been confirmed to be the most important antigenic polysaccharide on the TB cell surface. In this study, a convenient synthetic method has been developed for synthesizing three branched oligosaccharides derived from LAM, in which a core building block was prepared by enzymatic hydrolysis in flow chemistry with excellent yield. After several steps of glycosylations, the obtained oligosaccharides were conjugated with recombinant human serum albumin (rHSA) and the ex-vivo ELISA tests were performed using serum obtained from several TB-infected patients, in order to evaluate the affinity of the glycoconjugate products for the human LAM-antibodies. The evaluation results are positive, especially compound 21 that exhibited excellent activity which could be considered as a lead compound for the future development of a new glycoconjugated vaccine against TB.

Immobilized enzyme reactors based on nucleoside phosphorylases and 2'-deoxyribosyltransferase for the in-flow synthesis of pharmaceutically relevant nucleoside analogues.

In this work, a mono- and a bi-enzymatic analytical immobilized enzyme reactors (IMERs) were developed as prototypes for biosynthetic purposes and their performances in the in-flow synthesis of nucleoside analogues of pharmaceutical interest were evaluated. Two biocatalytic routes based on nucleoside 2'-deoxyribosyltransferase from Lactobacillus reuteri (LrNDT) and uridine phosphorylase from Clostridium perfrigens (CpUP)/purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) were investigated in the synthesis of 2'-deoxy, 2',3'-dideoxy and arabinonucleoside derivatives. LrNDT-IMER catalyzed the synthesis of 5-fluoro-2'-deoxyuridine and 5-iodo-2'-deoxyuridine in 65-59% conversion yield, while CpUP/AhPNP-IMER provided the best results for the preparation of arabinosyladenine (60% conversion yield). Both IMERs proved to be promising alternatives to chemical routes for the synthesis of nucleoside analogues. The developed in-flow system represents a powerful tool for the fast production on analytical scale of nucleosides for preliminary biological tests.

Design, synthesis and biological evaluation of new ganglioside GM3 analogues as potential agents for cancer therapy.

Ganglioside GM3 is well known as a tumor-associated carbohydrate antigen on several types of tumors. Many studies have demonstrated that GM3 plays roles in cells proliferation, adhesion, motility and differentiation, which is involved in the process of cancer development. In the present study, we developed methods to synthesize GM3 analogues conveniently. By enzymatic hydrolysis and chemical procedures, two novel analogues and two known analogues were synthesized, containing lactose and glucosamine. Then anti-proliferation and anti-migration activities were evaluated by cytotoxicity assays and wound healing tests, and the data demonstrated that these analogues exhibited anticancer activities. Based on our previous studies, the structure-activity relationships were discussed. This study could provide valuable sight to find new antitumor agents for cancer therapy.

Novel Vaccine Candidates against Tuberculosis.

Ranking above AIDS, Tuberculosis (TB) is the ninth leading cause of death affecting and killing many individuals every year. Drugs' efficacy is limited by a series of problems such as Multi- Drug Resistance (MDR) and Extensively-Drug Resistance (XDR). Meanwhile, the only licensed vaccine BCG (Bacillus Calmette-Guérin) existing for over 90 years is not effective enough. Consequently, it is essential to develop novel vaccines for TB prevention and immunotherapy. This paper provides an overall review of the TB prevalence, immune system response against TB and recent progress of TB vaccine research and development. Several vaccines in clinical trials are described as well as LAM-based candidates.

Chemoenzymatically synthesized ganglioside GM3 analogues with inhibitory effects on tumor cell growth and migration.

Ganglioside GM3, belonging to glycosphingolipid family, has been known as tumor-associated carbohydrate antigen on several types of tumor. Many studies have revealed that GM3 plays a role in cell proliferation, adhesion and differentiation, which is crucial in the process of cancer development. In the present study, we firstly synthesized novel mannose-containing GM3 analogues by enzymatic hydrolysis and chemical procedures. Then the antiproliferative activity of the novel analogues along with galactose-containing analogues we prepared previously was investigated and the data demonstrated that these analogues exhibited antiproliferative effect on K562 and HCT116 cells. Finally, the influence of these analogues on tumor cell migration was studied on B16, B16-F10 and HCCLM3 cells by wound healing test, because the migration of tumor cells represents one of the relevant factors in assessing the malignancy of cancer. This study could lay the foundation for optimizing leading compounds and provide valuable information for finding new antitumor drugs for cancer therapy.

Ganglioside GM3 and Its Role in Cancer.

Ganglioside GM3 is strongly related with human tumors, such as lung, brain cancers and melanomas, and more and more evidences have revealed that GM3 possesses powerful effects on cancer development and progression. GM3 is over expressed on several types of cancers, and can be as a tumor-associated carbohydrate antigen, used for immunotherapy of cancers. GM3 can also inhibit tumor cells growth by anti-angiogenesis or motility and so on. Especially, GM3 has effects on the EGFR tyrosine kinase signaling, uPAR-related signaling and glycolipid-enriched microdomains, which are essential for cancer signaling conduction. It is obvious that GM3 will be a promising target for cancer treatment.

Chemoenzymatically synthesized GM3 analogues as potential therapeutic agents to recover nervous functionality after injury by inducing neurite outgrowth.

Ganglioside GM3 is implicated in a variety of physiological and pathological processes. Due to GM3 exposes on the outer surface of cell membranes, it is strongly associated with cell adhesion, motility and differentiation. Neurite outgrowth is a key process in the development of functional neuronal circuits and regeneration of the nervous system after injury. In the present study, we used enzymatic hydrolysis and chemical synthesis to obtain novel galactose containing GM3 analogues. By enzymatic hydrolysis to prepare GM3 building block, we can avoid multiple chemical procedures. Next, we employed the PC12 cells as a model to evaluate the effects of GM3 analogues on neurite outgrowth with or without NGF induction. The biological tests showed that GM3 analogues could induce neurite outgrowth, which provides the valuable sights for potential nervous system treatment after injury.

Structural elucidation of a pectin from flowers of Lonicera japonica and its antipancreatic cancer activity.

To investigate polysaccharide structure from Lonicera japonica, and study its effects on behavior of pancreatic cells, a homogenous polysaccharide, LJ-02-1, was extracted and purified from flowers of L. japonica by DEAE-cellulose and Sephacryl S-200HR column. The molecular weight was estimated to be 54kDa. Monosaccharide composition was determined to be rhamnose, galacturonic acid, galactose and arabinose in the molar ratio of 10.77:7.88:15.45:65.89 by analyzing the PMP derivatives of the monosaccharides from 2M trifluoracetic acid hydrolysis via HPLC. Based on methylation analysis, partial acid hydrolysis, and NMR spectra, the polysaccharide was elucidated to be a rhamnogalacturonan backbone and substituted partly at C-4 of rhamnose. The branches were determined to be T- and 1,4,6-linked ß-d-Galp, T- and 1,5-linked α-l-Araf. The polysaccharide might inhibit BxPC-3 and PANC-1 pancreatic cancer cells growth at the concentration of 1mg/mL with inhibitory ratio of 66.7% and 52.1%, respectively.

Structural characterization of a polysaccharide from Chrysanthemum morifolium flowers and its antioxidant activity.

The flowers of Chrysanthemum morifolium were extracted by boiling water, and a water-soluble polysaccharide (CMJA0S2) with a molecular weight of 6.5 kDa was isolated by anion-exchange chromatography on a DEAE-cellulose column and gel permeation chromatography on a Sephacryl S-300 HR column. Monosaccharide composition analysis indicated that CMJA0S2 was composed of galactose, glucose, mannose and arabinose in molar ratio of 4.1: 3.3: 1.0: 2.3. According to linkage analysis, partial acid hydrolysis and NMR spectra, the backbone was shown to contain 1, 4-linked ß-Galp, 1, 4-linked ß-Glcp and 1, 4-linked ß-Manp, with branches substituted at C-6 of 1, 4-linked ß-Manp by 1, 6-linked ß-Galp and at O-6 of partial 1, 4-linked ß-Galp substituted by T-linked α-Glcp. About 40% of 1, 6-linked ß-Galp with T-linked α-Glcp was substituted at O-3 by α-Araf-(1→[5)-α-Araf-(1]3. The anti-oxidative analysis showed that CMJA0S2 could scavenge the DPPH radicals and relieve the damage of PC12 cells caused by H2O2, thus it could be regarded as a potential natural antioxidant.

Structural elucidation of a polysaccharide from Chrysanthemum morifolium flowers with anti-angiogenic activity.

The flowers of Chrysanthemum morifolium were extracted with 5% sodium hydroxide, yielding a neutral polysaccharide (JHB0S2) with a molecular weight of 16 kDa by anion-exchange chromatography on a DEAE-cellulose column and gel permeation chromatography on a Sephacryl S-200 HR column. JHB0S2 was found to contain glucose, xylose, arabinose and galactose in molar ratio of 2.9:2.3:1.0:1.2. Through the linkage analysis, partial acid hydrolysis and NMR spectra and so forth, indicated that its backbone consisted of 1,4-linked ß-Glcp, nearly 50% of which was substituted at O-6 by 1,2-linked α-Xylp terminated with Galp or Xylp. Furthermore, some of 1,2-linked α-Xylp was substituted at O-4 by α-Araf-(1→5)-α-Araf-(1→6)-ß-Galp. The biological test showed that JHB0S2 could inhibit the tube formation of HMEC-1 cells.