Rap1 is indispensable for TRF2 function in etoposide-induced DNA damage response in gastric cancer cell line

The telomeric protein TRF2, involving in telomeric and extratelomeric DNA damage response, has been previously reported to facilitate multidrug resistance (MDR) in gastric cancer cells by interfering ATM-dependent DNA damage response induced by anticancer drugs. Rap1 is the TRF2-interacting protein in the shelterin complex. Complex formation between Rap1 and TRF2 is essential for their function in telomere and end protection. Here we focus on the effects of Rap1 on TRF2 function in DNA damage response induced by anticancer drugs. Both Rap1 and TRF2 expression were upregulated in SGC7901 and its MDR variant SGC7901/VCR after etoposide treatment, which was more marked in SGC7901/VCR than in SGC7901. Rap1 silencing by siRNA in SGC7901/VCR partially reversed the etoposide resistance. And Rap1 silencing partially reversed the TRF2-mediated resistance to etoposide in SGC7901. Rap1 silencing did not affect the TRF2 upregulation induced by etoposide, but eliminated the inhibition effect of TRF2 on ATM expression and ATM phosphorylation at serine 1981 (ATM pS1981). Furthermore, phosphorylation of ATM targets, including γH2AX and serine 15 (S15) on p53, were increased in Rap1 silencing cells in response to etoposide. Thus, we confirm that Rap1, interacting with TRF2 in the shelterin complex, also has an important role in TRF2-mediated DNA damage response in gastric cancer cells treated by etoposide.

Elevated plasma osteopontin level is predictive of cirrhosis in patients with hepatitis B infection

BACKGROUND

Osteopontin (OPN) was shown to play an important role in the pathogenesis of various inflammatory and fibrotic processes and elevated in fibrotic liver of mouse model. However, the significance of OPN in hepatitis B virus (HBV)-induced liver cirrhosis (LC) remains unclear and is therefore evaluated in this study.

METHODS

Thirty-nine patients with HBV-induced LC, 30 patients with HBV infection but without cirrhosis, 11 patients with HBV-related hepatocellular carcinoma (HCC) and 14 additional healthy controls were enrolled in this study. Plasma levels of OPN were measured with enzyme-linked immunosorbent assay and the relationship between OPN and clinical parameters was evaluated.

RESULTS

When compared to HBV infection group (median 2.16 ng/ml), plasma levels of OPN were significantly increased in cirrhosis (4.52 ng/ml, p < 0.001) and cancer group (13.38 ng/ml, p < 0.001). The OPN level was correlated with the severity of liver damage according to Child-Pugh classification (p = 0.003). It showed at least comparable sensitivity and specificity to predict cirrhosis as aspartate aminotransferase to platelet ratio index, a previously established non-invasive serum marker of cirrhosis.

CONCLUSIONS

These data suggest that OPN could be used to evaluate the existence of LC, as OPN has previously been reported to be increased in the HCC; this unique feature makes OPN a promising candidate for prediction biomarker in the long-time surveillance of patients with HBV infection to evaluate the risk of cirrhosis and cancer.

The correlation between cotransplantation of mesenchymal stem cells and higher recurrence rate in hematologic malignancy patients: outcome of a pilot clinical study

In this open-label randomized clinical trial, HLA-identical sibling-matched hematopoietic stem cells (HSC) were transplanted (non-MSCs group, n=15) or cotransplanted with mesenchymal stem cells (MSCs) (MSCs group, n=10) in hematologic malignancy patients. The median number of MSCs infused was 3.4 x 10(5) kg(-1) (range, 0.3-15.3 x 10(5) kg(-1)). MSCs infusions were well tolerated. The median time to neutrophil engraftment (absolute neutrophil count >0.5 x 10(9) l(-1)) was 16 days for MSCs group and 15 days for non-MSCs group. The median time to platelet engraftment (platelet count >50 x 10(9) l(-1)) was 30 and 27 days, respectively. Grades II-IV acute graft-versus-host disease (GVHD) was observed respectively, in one (11.1%) and eight (53.3%) evaluable patients. Chronic GVHD was found in one (14.3%) and four (28.6%) evaluable patients. The number of patients who relapsed were six (60.0%) and three (20.0%), and the 3-year disease-free survivals were 30.0 and 66.7%, respectively. Thus cotransplantation of MSCs and HSCs may prevent GVHD, but the relapse rate is obviously higher than the control group. We conclude that use of MSCs must be handled with extreme caution before a large-scale clinical trial is performed.