A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro.

Therapeutic numbers of antigen-specific cytotoxic T lymphocytes (CTLs) are key effectors in successful adoptive immunotherapy. However, efficient and reproducible methods to meet the qualification remain poor. To address this issue, we designed the artificial antigen-presenting cell (aAPC) system based on poly(lactic-co-glycolic acid) (PLGA). A modified emulsion method was used for the preparation of PLGA particles encapsulating interleukin-2 (IL-2). Biotinylated molecular ligands for recognition and co-stimulation of T cells were attached to the particle surface through the binding of avidin-biotin. These formed the aAPC system. The function of aAPCs in the proliferation of specific CTLs against human Flu antigen was detected by enzyme-linked immunospot assay (ELISPOT) and MTT staining methods. Finally, we successfully prepared this suitable aAPC system. The results show that IL-2 is released from aAPCs in a sustained manner over 30 days. This dramatically improves the stimulatory capacity of this system as compared to the effect of exogenous addition of cytokine. In addition, our aAPCs promote the proliferation of Flu antigen-specific CTLs more effectively than the autologous cellular APCs. Here, this aAPC platform is proved to be suitable for expansion of human antigen-specific T cells.

Aplasia Ras homologue member I overexpression induces apoptosis through inhibition of survival pathways in human hepatocellular carcinoma cells in culture and in xenograft.

The aim of the present study was to determine the effects of ARHI (aplasia Ras homologue member I; also known as DIRAS3), a member of the Ras superfamily, on HCC (hepatocellular carcinoma) cells and to define the molecular pathways involved. Stable transfection of ARHI into the HCC cell line Hep3B that lacks expression of this gene reduced cell proliferation significantly as compared with the transfection of empty vector (P<0.01). Moreover, the re-expression of ARHI induced significant apoptosis, whereas a few vector transfectants or non-transfected cells displayed apoptosis. Mechanistically, ARHI restoration impeded the activation of both Akt (also called protein kinase B) and NF-κB (nuclear factor κB). In vivo, restoring ARHI also exerted suppressive effects on xenograft tumour growth, which was coupled with increased apoptosis. Together, these results indicate that ARHI has pro-apoptotic effects on HCC cells, which is associated with the inactivation of both Akt and NF-κB survival pathways.

Simultaneous measurements of serum AFP, GPC-3 and HCCR for diagnosing hepatocellular carcinoma.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is a prevalent malignant tumor. Tumor markers are very useful in early diagnosis; however a single marker is rather limited. We launched a test to increase the diagnostic sensitivity through the combined detection. METHODOLOGY: Serum concentration of three tumor-markers, Glypican-3 (GPC-3), Human-Cervical-Cancer-Oncogene (HCCR) and a-fetoprotein (AFP), were determined in 189 samples: 101 cases of HCC, 40 cases of cirrhosis, 18 cases of hepatitis and 30 cases of control healthy donors. Every marker was evaluated for its diagnostic value by one-way-analysis-of-variance and receiver-operating-characteristics analysis. RESULTS: GPC-3 was the best marker with an area under the curve (AUC) of 0.892; using 26.8ng/mL as the cut-off for HCC diagnosis, GPC-3 has a sensitivity of 51.5% and maintains a specificity of 92.8%. HCCR, with an AUC of 0.831, can reach a sensitivity of 22.8% and maintain a specificity of 90.9% if the cut-off is set as 58.8mAU/mL. With an AUC of 0.827, the efficacy and sensitivity of AFP were 36.6% and 98.5% when using 199.3ng/mL as the cut-off. No significant correlation was found between these three markers. Simultaneously detecting three markers can significantly increases the sensitivity to 80.2%, much higher than AFP alone. CONCLUSIONS: GPC-3 and HCCR are useful tumor markers complementary to AFP for clinical diagnosis of HCC.

Overexpression of human telomerase reverse transcriptase promotes the motility and invasiveness of HepG2 cells in vitro.

Recent studies have indicated that telomerase activity promotes cancer invasion and metastasis, but the underlying mechanism remains unclear. Several studies have shown that expression of exogenous human telomerase reverse transcriptase (hTERT) can promote motility and invasiveness among telomerase-negative tumor cells, and inhibition of endogenous telomerase activity can reduce invasiveness in tumor cells. However, whether overexpression of hTERT can further enhance the motility and invasiveness of telomerase­positive tumor cells has yet to be determined. In the present study, we showed that stable overexpression of hTERT can increase telomerase activity and telomere length, which significantly promotes the invasive and metastatic potential of telomerase­positive HepG2 cells but does not affect cell proliferation. Further analysis suggested that enhanced invasiveness and metastasis may act through corresponding upregulation of mRNA and protein expression of matrix metalloproteinase 9 (MMP9) and Ras homolog gene family member C (RhoC). Our study indicated that exogenous expression of hTERT may promote invasiveness and metastasis through upregulation of MMP9 and RhoC.