To maintain the homeostasis of stem cells and prevent their ability to initiate tumorigenesis, it is important to identify and modify factors that prevent or accelerate stem cell senescence. We used microarrays to attempt to identify such factors in human amniotic fluid (HAF)-derived stem cells.
To identify gene expression changes over a time course, we compared gene expression profiles of HAF-derived stem cells in different passages (1st, 2nd, 4th, 6th, 8th, and 10th) using a Sentrix Human illumina microarray.
Of the 25,804 genes in the microarray chip, 1,970 showed an over 2-fold change relative to the control (the 1st passage)-either upregulated or downregulated. Quantitative real-time PCR validated the microarray data for selected genes: markedly increased genes were CXCL12, cadherin 6 (CDH6), and folate receptor 3 (FOLR3). Downregulated genes included cyclin D2, keratin 8, insulin-like growth factor 2 (IGF2), natriuretic peptide precursor B (NPPB) and cellular retinoic acid binding protein 2 (CRABP2). The expression pattern of the selected genes was consistent with the microarray data except for CXCL12 and IGF2. Interestingly, the expression of NPPB was dramatically downregulated along the time course; it was almost completely shut-down by the 10th passage. In contrast, FOLR3 mRNA expression was dramatically increased.
Taken together, although a function for NPPB and FOLR3 in stem cell senescence has not been reported, our results strongly suggest that NPPB and/or FOLR3 play a significant role in the regulation of stem cell senescence.
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Human papillomavirus (HPV) infection has a significant role in cervical carcinogenesis, and HPV oncoprotein E7 plays an important part in the formation and maintenance of cervical cancer. Interleukin-12 (IL-12) has been reported to induce a cellular immune response, and to suppress the tumor growth and the E7 production. Here we describe the use of adenoviral delivery of the HPV 16 E7 subunit (AdE7) along with adenoviral delivery of IL-12 (AdIL-12) in mice with HPV-associated tumors.
Mice were injected with TC-1 cells to establish TC-1 tumor, and then they were immunized with AdIL-12 and/or AdE7 intratumorally. The anti tumor effects induced by AdIL-12 and/or E7 were evaluated by measuring the size of the tumor. E7-specific antibody and INF-γ production in sera, and the T-helper cell proliferative responses were then measured. Cytotoxic T-lymphocyte (CTL) and T cell subset depletion studies were also performed.
Combined AdIL-12 and AdE7 infection at the tumor sites significantly enhanced the antitumor effects more than that of AdIL-12 or AdE7 single infection. This combined infection resulted in regression of the 9 mm sized tumors in 80% of animals as compare to the PBS group. E7-specific antibody and INF-γ production in the sera, and the T-helper cell proliferative responses were significantly higher with coinfection of AdIL-12 and AdE7 than with AdIL-12 or AdE7 alone. CTL response induced by AdIL-12 and AdE7 in the coinjected group suggested that tumor suppression was mediated by mostly CD8+ and only a little by the CD4+ T cells.
IL-12 and E7 application using adenovirus vector showed antitumor immunity effects against TC-1 tumor, and this system could be use in clinical applications for HPV-associated cancer. (ED note: nice abstract.)
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Photodynamic therapy (PDT) is a novel treatment modality, which produces local tissue necrosis with laser light following the prior administration of a photosensitizing agent. Radachlorin® has recently been shown to be a promising PDT sensitizer. In order to elucidate the antitumor effects of PDT using Radachlorin® on cervical cancer, growth inhibition studies on a HPV-associated tumor cell line, TC-1 cells
TC-1 tumor cells were exposed to various concentrations of Radachlorin® and PDT, with irradiation of 12.5 or 25 J/cm2 at an irradiance of 20 mW/cm2 using a Won-PDT D662 laser at 662 nm
The results showed that irradiation of TC-1 tumor cells in the presence of Radachlorin® induced significant cell growth inhibition. Animals with established TC-1 tumors exhibited significantly smaller tumor sizes over time when treated with Radachlorin® and irradiation.
PDT after the application of Radachlorin® appears to be effective against TC-1 tumors both
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