A Triptolide Loaded HER2-Targeted Nano-Drug Delivery System Significantly Suppressed the Proliferation of HER2-Positive and BRAF Mutant Colon Cancer.

BACKGROUND: Colon cancer (CRC) was a malignant tumor and there were about 25% of patients with tumor metastasis at diagnosis stage. Chemotherapeutic agents for metastatic CRC patients were with great side effects and the clinical treatment results of advanced CRC were still not satisfactory. Human epidermal growth factor receptor 2 (HER2) is overexpressed in some CRC patients and is an effective target for CRC patient treatment. Anti-HER2 therapy had a beneficial role in the treatment of HER2-positive metastatic CRC with fewer side effects. CRC patients with BRAF mutations were resistant to HER2 antibodies treatment. Therefore, there was an urgent need to develop new therapeutic agents. METHODS: HER2 targeted nanoparticles (TPLNP) drug delivery system loading triptolide (TPL) were prepared and identified. The effects of TPLNP and free TPL on cell viability, targeting and cell cycle progression on HT29 (BRAF mutation) with HER2 overexpression, were evaluated by Cell Counting Kit-8 (CCK8), Fluorescence Activating Cell Sorter (FACS) and immunofluorescence methods, respectively. The anti-tumor efficacies of TPLNP were evaluated in subcutaneous xenograft model of colon cancer and the survival rate, tumor volume, liver and kidney indexes of tumor-bearing mice were measured. RESULTS: TPLNP was small in nanosize (73.4±5.2nm) with narrow size distribution (PDI=0.15±0.02) and favorable zeta potential (pH=9.6, zeta potential: -57.3±6.69mV; pH=7.0, zeta potential: -28.7±5.1mV; pH=5.6, zeta potential: -21.1±4.73mV). Comparing with free TPL treatment group, TPLNP developed stranger colon cancer-killing efficiency in a dose- and time-dependent manner detected with CCK8 method; achieved good in vitro colon cancer targeting detected with flow cytometry and immunofluorescence experiments; enhanced more HT29-HER2 apoptosis and induced more cell cycle arrested in G1-S phase detected with FACS in vitro. As for in vivo antitumor response, TPLNP remarkably inhibited the growth of colon cancer in the colon cancer xenograft model, significantly improved the survival rate and did not exhibit significant liver and kidney toxicity in contrast with free TPL in vivo. CONCLUSION: TPLNP was effectively against colon cancer with HER2 overexpression and BRAF mutation in pre-clinical models. In summary, the TPLNP appeared to be a promising treatment option for CRC in clinical application based on improved efficacy and the favorable safety profile.

Mecp2-mediated Epigenetic Silencing of miR-137 Contributes to Colorectal Adenoma-Carcinoma Sequence and Tumor Progression via Relieving the Suppression of c-Met.

The molecular mechanisms underlying colorectal cancer (CRC) development remain elusive. In this study, we examined the miRNA and mRNA expressions in the adenoma-carcinoma sequence (ACS), a critical neoplastic progression in CRC development. We found that miR-137 was down-regulated in all adenoma and carcinoma tissues. Low miR-137 levels were correlated negatively with tumor progression and metastasis. Then we identified the inhibition effect of the miR-137 in CRC development, both in CRC cell lines and mouse models. MiR-137 was shown to control CRC cell proliferation, colony formation, migration and invasion and to control tumor growth and metastasis. We further confirmed the negative association between miR-137 and c-Met expression and thus validated this important oncogene as the target of miR-137 in CRC. In addition, we found a DNA methyl-CpG-binding protein, Mecp2, was up-regulated in ACS tissues via mRNA sequencing. Further experiment showed that miR-137 expression in CRC was subjected to epigenetic regulation mediated by Mecp2. We also confirmed c-Met expression can be up-regulated by silencing of miR-137 and suppressed by coexpression of Mecp2 and miR-137. These findings highlight the critical role of miR-137-c-Met nexus in CRC development and reveal Mecp2-regulated epigenetic silence causes the downregulation of miR-137 in colorectal adenoma and carcinoma.

[A comparison study on the physical/chemical properties and immunomodulatory activities of mycelial polysaccharide extracts from five Ganoderma species].

Five Ganoderma species, including G. lucidum, G. tsugae, G. oerstedii, G. resinaceum and G. subamboinens, were parallel studied under an identical condition. These species were cultivated using liquid fermentation and their mycelia polysaccharides were extracted and compared on the physical/chemical properties and in vitro immunomodulatory activities. These results showed that the polysaccharide yields varied markedly among different species, and G. oerstedii was the highest among the five. However, HPLC analysis showed all the polysaccharide extracts had similar molecular weight distributions and monosaccharide compositions. They all contained glucose, galactose, mannose, glucosamine hydrochloride and fucose. In vitro assays, these polysaccharide extracts significantly stimulated phagocytosis and nitric oxide production by RAW 264.7 macrophage cell line, and G. subamboinens exerted the strongest potency. When Con A was not or presented, they all showed an up-or-down immunomodulatory effect on mouse splenocyte proliferation. The results illustrate that in addition to G. lucidum and G. tsugae, which are the two mostly studied and applied species, other Ganoderma species can also produce polysaccharides with similar physical/chemical properties and with similar immunomodulatory activities.