Qian Ding

Identification of PAQR3 as a new candidate tumor suppressor in hepatocellular carcinoma

Progestin and adipoQ receptor family member III (PAQR3) is a regulator that negatively modulates the Ras/Raf/MEK/ERK signaling cascade and the GPCR Gβγ subunit signaling pathway. The role of PAQR3 in hepatocellular carcinoma (HCC) has not been elucidated. The present study investigated the expression of PAQR3 and its prognostic value in primary HCC patients. Furthermore, the functional aspects of PAQR3 were also studied using an in vitro cell model. PAQR3 expression was examined in paired HCC and adjacent noncancerous tissues using real-time quantitative RT-PCR (62 pairs) and western blotting (26 pairs). We also analyzed PAQR3 expression in 132 additional HCC samples by immunohistochemistry. The functional impact of PAQR3 on the proliferation and colony formation of an HCC cell line was analyzed by transfecting cells with a full-length PAQR3 expression vector or siRNA targeting PAQR3. The expression of PAQR3 was significantly decreased in the cancer tissues. Clinicopathological analyses showed that the expression of PAQR3 was significantly correlated with expression of serum α-fetoprotein (AFP), mitotic count, tumor size, histological grade and recurrence. Notably, Kaplan-Meier survival curves revealed a correlation between decreased expression of PAQR3 and the poor prognosis of HCC patients. Multivariate analyses showed that PAQR3 expression is an independent prognostic marker for overall and disease-free survival of HCC patients. Furthermore, restoring PAQR3 expression in HCC cells significantly diminished Hep3B cell proliferation and colony formation. Silencing PAQR3 expression in hepatic normal cell line LO2 significantly enhanced cell growth. PAQR3 may play an important role in the progression of HCC and serve as a potential candidate for the targeted therapy of HCC.

Alterations of cell cycle control proteins SHP‑1/2, p16, CDK4 and cyclin D1 in radioresistant nasopharyngeal carcinoma cells

The primary treatment for nasopharyngeal carcinoma (NPC) is radiotherapy, with or without concurrent chemotherapy. However, resistance to radiotherapy is not uncommon. The aim of the present study was to establish a radioresistant NPC cell line to study the molecular mechanisms of radioresistance by measuring the expression of cell cycle control proteins src homology 2 domain-containing phosphatase (SHP)-1/2, p16, CDK4 and cyclin D1. Human nasopharyngeal carcinoma CNE-2 cells were cultured, divided into two groups (CNE-2S1 and CNE-2S2) and irradiated with a dose of 6 Gy x5 or 2 Gy x15, respectively. The cells were subcultured between doses of irradiation. The surviving sublines (CNE-2S1 and CNE-2S2 clones) were then passaged for three months and their radiosensitivity was determined. The cell cycle distribution and protein expression of SHP-1/2, p16, CDK4 and cyclin D1 in parental and progenitor cell lines were measured. Small interfering (si)RNA-mediated knockdown of SHP-1 and SHP-2 in the NPC cells was used to further examine their roles in radiosensitivity and cell cycle distribution. CNE-2S1, a radio-resistant cell line, had a significantly higher percentage of cells in S phase and a lower percentage of cells in G1 phase, enhanced expression levels of SHP-1, CDK4 and cyclin D1, and reduced expression of p16, respectively, as compared with the parent cells. Stable suppression of SHP-1 mRNA in CNE-2 cells resulted in increased radiosensitivity compared with the parental cells, a decrease in the number of cells in S phase and an increase in the expression of p16. The results suggested that the SHP-1/p16/cyclin D1/CDK4 pathway may have a role in regulating radiosensitivity and cell cycle distribution in nasopharyngeal cells.

Biocompatibility of functionalized designer self‐assembling nanofiber scaffolds containing FRM motif for neural stem cells

Peptide self-assembling scaffolds have been widely used in tissue engineering. Much work has been focused on modifying the self-assembling scaffolds with functional motifs for desired biological activities. We report here the development of a biological material designed specifically for neural tissue engineering (NTE). Using RADA-16 (AcN-RADARADARADARADA-CONH2) as a base scaffold, we synthesized a 31 amino acid peptide RADA-FRM (AcN-RADARADARADARADAGGSIDRVEPYSSTAQ-CONH2) containing the neural cell adhesion molecule (NCAM)-derived mimetic peptide FRM (SIDRVEPYSSTAQ), which could undergo self-assembly into a nanofiber scaffold. We tested the characterization of the nanofiber scaffold using atomic force microscopy (AFM) and accessed the rheological properties of FRM-containing nanofiber scaffold (FRM-NS). Then we examined its biocompatibility on neural stem cells (NSCs) from neonatal rats. Regrettably, we found that FRM-NS had no effect on differentiation of NSCs. However, we tested that FRM-NS was noncytotoxic. Furthermore, compared to pure RADA-16 scaffold, we found that the designer self-assembling peptide scaffold containing FRM motif could significantly promote NSCs proliferation and stimulate NSCs migration into the three-dimensional scaffold. Our results indicate that the novel designer peptide scaffold containing FRM had excellent biocompatibility with NSCs and may be useful for central nervous tissue repair.

SHP1-mediated cell cycle redistribution inhibits radiosensitivity of non-small cell lung cancer

BackgroundRadioresistance is the common cause for radiotherapy failure in non-small cell lung cancer (NSCLC), and the degree of radiosensitivity of tumor cells is different during different cell cycle phases. The objective of the present study was to investigate the effects of cell cycle redistribution in the establishment of radioresistance in NSCLC, as well as the signaling pathway of SH2 containing Tyrosine Phosphatase (SHP1).MethodsA NSCLC subtype cell line, radioresistant A549 (A549S1), was induced by high-dose hypofractionated ionizing radiations. Radiosensitivity-related parameters, cell cycle distribution and expression of cell cycle-related proteins and SHP1 were investigated. siRNA was designed to down-regulate SHP1expression.ResultsCompared with native A549 cells, the proportion of cells in the S phase was increased, and cells in the G0/G1 phase were consequently decreased, however, the proportion of cells in the G2/M phase did not change in A549S1 cells. Moreover, the expression of SHP1, CDK4 and CylinD1 were significantly increased, while p16 was significantly down-regulated in A549S1 cells compared with native A549 cells. Furthermore, inhibition of SHP1 by siRNA increased the radiosensitivity of A549S1 cells, induced a G0/G1 phase arrest, down-regulated CDK4 and CylinD1expressions, and up-regulated p16 expression.ConclusionsSHP1 decreases the radiosensitivity of NSCLC cells through affecting cell cycle distribution. This finding could unravel the molecular mechanism involved in NSCLC radioresistance.

Increased expression of SHP-1 is associated with local recurrence after radiotherapy in patients with nasopharyngeal carcinoma

Abstract Background. Nasopharyngeal carcinoma (NPC) is a major cancer in southern China. Src homology phosphatase-1 (SHP-1) is a tyrosine phosphatase that regulates growth, differentiation, cell cycle progression, and oncogenesis. We determined the clinical significance of SHP-1 expression in the tumours of NPC patients from southern China who were treated with radiotherapy. Patients and methods. SHP-1 expression was determined by real-time polymerase chain reaction (PCR) and western blotting of NPC tissue samples of 50 patients and nasopharyngeal tissues of 50 non-NPC patients who had chronic nasopharyngeal inflammation. SHP-1 expression was measured in NPC tissue samples of 206 patients by immunohistochemistry and survival analysis was performed. Results. The tumours of NPC patients had significantly increased expression of SHP-1 at mRNA and protein levels relative to patients with chronic nasopharyngeal inflammation. Survival analysis of NPC patients indicated that SHP-1 expression was significantly associated with poor local recurrence-free survival (p = 0.008), but not with nodal recurrence- free survival, distant metastasis-free survival, or overall survival. Conclusions. SHP-1 appears to be associated with radiation resistance of NPC cells and can be considered as a candidate marker for prognosis and/or therapeutic target in patients with this type of cancer.

Influence of designer self-assembling nanofiber scaffolds containing anti-cancer peptide motif on hepatoma carcinoma cells

Nanotechnology provides a novel scope for cancer therapeutics. Nanoscale platforms could influence the survival, adhesion, and migration of cancer cells through altering the tumor microenvironments. We report here the development of an anti-tumor material designed specifically for cancer therapy. We synthesized a 48-amino acid peptide RADA-KLA, which could self-assemble into nanostructures with antitumor activities. We tested the microstructure of RADA-KLA nanofiber scaffold using transmission electron microscopy (TEM) and accessed rheological properties of the material. Then, we demonstrated the effects of RADA-KLA nanofibers on hepatoma carcinoma cells. We found that RADA-KLA self-assembling peptide scaffold could induce cell death, and inhibit adhesion and migration of hepatoma carcinoma cells. Our results indicate that the designer peptide scaffold has anti-tumor activities and could be used for cancer therapy.