Applications of inflammation-derived gingival stem cells for testing the biocompatibility of dental restorative biomaterials.

BACKGROUND: Normal or inflamed gingival tissues are regarded as a source of mesenchymal stem cells (MSCs) abundant and easily accessible through minimally invasive dental procedures. Due to the proximity of dental resin composites to gingival tissues and to the possible local cytotoxic effect of the eluted components, gingiva-derived MSCs could be used to investigate the biocompatibility of dental biomaterials. PURPOSE: The present research aimed to isolate (MSCs) from inflamed and normal gingiva, to fully characterize them and to observe their behavior in relation with some commercial resin composite materials and one experimental material. MATERIAL AND METHODS: Following their isolation, putative MSCs from both gingival sources were grown under the same culture conditions and characterized by immunophenotyping of cell surface antigens by flow-cytometry and transcription factors by immunocytochemical staining. Moreover, stemness gene expression was evaluated by RT-PCR analysis. Multipotent mesenchymal differentiation potential was investigated. Osteogenic and neurogenic differentiated cells were highlighted by immunocytochemical staining, chondrogenic cells by cytochemical staining, and adipocytes by cytochemical staining and spectrophotometry, respectively. Resin composite cytotoxicity was evaluated by cell membrane fluorescent labeling with PKH 26 and MTT assay. The results of PKH labeling were statistically analysed using two-way RM ANOVA with Bonferroni post-tests. For MTT assay, two-way RM ANOVA with Bonferroni post-tests and unpaired t test with Welch's correction were used. RESULTS: A similar expression pattern of surface markers was observed. The cells were positive for CD105, CD73, CD90, CD49e, CD29, CD44 and CD166 and negative for CD45, CD34, CD14, CD79, HLA-DR and CD117 indicating a mesenchymal stem cell phenotype. The qRT-PCR analysis revealed a low gene expression for NOG, BMP4 and Oct3/4 and an increased expression for Nanog in both cells lines. Immunocytochemical analysis highlighted a more intense protein expression for Nanog, Oct3/4 and Sox-2 in MSCs derived from normal gingiva than from inflamed gingiva. Multipotent differentiation capacity of MSCs isolated from both sources was highlighted. The tested materials had no hazardous effect on MSCs as the two cell lines developed well onto resin composite substrates. Cell counting revealed some significant differences in the number of PKH-labeled MSCs at some experimental moments. Also, some differences in cell viability were recorded indicating better developmental conditions offered by some of the tested biomaterials. CONCLUSIONS: The experimental resin composite behaved like the most biocompatible commercial material. Inflamed gingiva-derived MSCs retain their stem cell properties and could be used as a valuable cell line for testing dental biomaterials.

The significance of PDGF expression in serum of colorectal carcinoma patients--correlation with Duke's classification. Can PDGF become a potential biomarker?

BACKGROUND: The expression of serum angiogenic factors has been associated with tumor dissemination and poor prognosis in multiple cancer types. However, it is still unclear whether these angiogenic molecules can be used as an independent molecular marker or in correlation with other parameters for predicting the prognosis of colorectal carcinoma (CRC)patients. METHODS: Protein expression was evaluated in 28 CRC and 10 control cases using Angiogenesis Fast Quant technology. RESULTS: In this study, we found downregulation of PDGF-bb protein expression in the serum of patients with colorectal cancer compared with the control group. Thus, PDGF-bb might play an essential function in the progression of CRC. CONCLUSIONS: Our study indicated that the PDGF-bb protein expression might be an independent prognostic marker or in association with other parameters for CRC patients.

The clinical implications of platelet derived growth factor B, vascular endothelial growth factor and basic fibroblast growth factor in colorectal cancer.

Colorectal cancer (CRC) remains a major health problem worldwide. Angiogenesis is a key process for tumor growth and metastasis. The conversion of tumor cells to an angiogenic phenotype involves the change in the balance of angiogenic growth factors and angiogenesis inhibitors. In our study we evaluated by qRT-PCR the level of expression of 3 growth factors involved in angiogenesis: platelet derived growth factor-B (PDGFb), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) in patients with different stages of colon cancer. Our results showed the level of VEGF increased on all tumor without difference, statistically significant according with tumor stage whereas the others the levels of bFGF and PDGF were higher, statistically significant, on tumor classified stage B compared with stage C. The early implication of these molecules in colon carcinogenesis justifies the development of new biologic individualized therapies.

p53 gene therapy using RNA interference.

p53 gene, discovered almost 35 years ago, keeps the main role in cell cycle control, apoptosis pathways and transcription. p53 gene is found mutated in more than 50% of all human cancers in different locations. Many structures from viral to non viral were designed to incorporate and deliver in appropriate conditions forms of p53 gene or its transcripts, systemically to target tumor cells and to eliminate them through apoptosis or to restore the normal tumor suppressor gene role. Each delivery system presents advantages and low performance in relation to immune system recognition and acceptance. One of the major discoveries in the last years, silencing of RNA, represents a powerful tool for inhibiting post transcriptional control of gene expression. According to several studies, the RNA silencing technology for p53 transcripts together with other carriers or transporters at nano level can be used for creating new therapeutic models. RNA interference for p53 uses different double-stranded (ds) molecules like short interfering (si) RNA and, despite the difficulty of introducing them into mammalian cells due to immune system response, it can be exploited in cancer therapy.