Co-assembled nanocomplexes comprising epigallocatechin gallate and berberine for enhanced antibacterial activity against multidrug resistant Staphylococcus aureus.

Berberine (BBR), a major alkaloid in Coptis chinensis, and (-)-epigallocatechin-3-gallate (EGCG), a major catechin in green tea, are two common phytochemicals with numerous health benefits, including antibacterial efficacy. However, the limited bioavailability restricts their application. Advancement in the co-assembly technology to form nanocomposite nanoparticles precisely controls the morphology, electrical charge, and functionalities of the nanomaterials. Here, we have reported a simple one-step method for preparing a novel nanocomposite BBR-EGCG nanoparticles (BBR-EGCG NPs). These BBR-EGCG NPs exhibit improved biocompatibility and greater antibacterial effects both in vitro and in vivo relative to free-BBR and first-line antibiotics (i.e., benzylpenicillin potassium and ciprofloxacin). Furthermore, we demonstrated a synergistic bactericidal effect for BBR when combined with EGCG. We also evaluated the antibacterial activity of BBR and the possible synergism with EGCG in MRSA-infected wounds. A potential mechanism for synergism between S. aureus and MRSA was also explored through ATP determination, the interaction between nanoparticles and bacteria, and, then, transcription analysis. Furthermore, our experiments on S. aureus and MRSA confirmed the biofilm-scavenging effect of BBR-EGCG NPs. More importantly, toxicity analysis revealed that the BBR-EGCG NPs had no toxic effects on the major organs of mice. Finally, we proposed a green method for the fabrication of BBR-EGCG combinations, which may provide an alternative approach to treating infections with MRSA without using antibiotics.

REG3A promotes the proliferation, migration, and invasion of gastric cancer cells.

The mechanism underlying the metastasis of gastric cancer (GC) cells remains elusive. REG3A is considered an oncogene in various cancers, but in GC its role is unclear. Here, we report that the expression of REG3A was significantly increased in the tumor tissues of patients with GC compared with the matched normal tissues. Knockdown of REG3A induced by specific small interfering RNA (siRNA) significantly repressed the proliferation of GC cells for 24 h or 48 h. Moreover, knockdown of REG3A significantly suppressed the migration, invasion, and adhesion of GC cells in vitro. Furthermore, knockdown of REG3A reduced the phosphorylation of JAK2 and STAT3, and altered the messenger RNA (mRNA) and protein expression levels of E-cadherin, Snail, RhoC, MTA1, MMP-2, and MMP-9. Taken together, REG3A is overexpressed in GC and promotes the proliferation, migration, invasion, and adhesion of GC cells by regulating the JAK2/STAT3 signal pathway. REG3A may be a potential therapeutic target for GC.

The carcinogenic potential of extractable organic matter from urban airborne particles in Shanghai, China.

The genotoxicity of extractable organic matter (EOM) from airborne particles in Shanghai has been determined using short-term bioassays. EOM samples were investigated using cell morphological transformation and two-stage model of mouse skin tumorigenicity assays to detect their carcinogenic activity. DNA adducts were detected using the 32P-postlabeling technique. The results showed that EOMs induced cell morphological transformation and played a role in tumor-initiating carcinogenesis. The EOMs of airborne particles from different districts of Shanghai had similar carcinogenic activity except the result of sample E (at downtown of Shanghai) was relatively high. The polycyclic aromatic hydrocarbon (PAH) fraction makes a major contribution to carcinogenic activity according to the results of cell morphological transformation assay. DNA adducts were also detected in skin, liver, and kidney of mouse after treatment with EOMs. It is suggested that the urban airborne particles in Shanghai, which show carcinogenic potential and genotoxic activity in our bioassays, may be responsible for the increased incidence of lung cancer in Shanghai in last few years.