Sun-Young Kwak

Protein Expression Profile using Two-Dimensional Gel Analysis in Squamous Cervical Cancer Patients

PURPOSE Screening in cervical cancer is now progressing to discover candidate genes and proteins that may serve as biological markers and that play a role in tumor progression. We examined the protein expression patterns of the squamous cell carcinoma (SCC) tissues from Korean women with using two- dimensional polyacrylamide gel electrophoresis (2-DE) and matrix assisted laser desorption/ionization-time of flight (MALDI- TOF) mass spectrometer. MATERIALS AND METHODS Normal cervix and SCC tissues were solubilized and 2-DE was performed using pH 3 approximately 10 linear IPG strips of 17 cm length. The protein expression was evaluated using PDQuest 2-D software. The differentially expressed protein spots were identified with a MALDI-TOF mass spectrometer, and the peptide mass spectra identifications were performed using the Mascot program and by searching the Swiss-prot or NCBInr databases. RESULTS A total of 35 proteins were detected in SCC. 17 proteins were up-regulated and 18 proteins were down-regulated. Among the proteins that were identified, 12 proteins (pigment epithelium derived factor, annexin A2 and A5, keratin 19 and 20, heat shock protein 27, smooth muscle protein 22 alpha, alpha-enolase, squamous cell carcinoma antigen 1 and 2, glutathione S-transferase and apolipoprotein a1) were protein previously known to be involved in tumor, and 21 proteins were newly identified in this study. CONCLUSION 2-DE offers the total protein expression profiles of SCC tissues; further characterization of these differentially expressed proteins will give a chance to identify the badly needed tumor-specific diagnostic markers for SCC.

Photodynamic therapy with recombinant adenovirus AdmIL-12 enhances anti-tumour therapy efficacy in human papillomavirus 16 (E6/E7) infected tumour model.

Immunotherapy with photodynamic therapy (PDT) offers great promise as a new alternative for cancer treatment; however, its use remains experimental. Here we investigated the utility of adenoviral delivery of interleukin‐12 (AdmIL‐12) as an adjuvant for PDT in mouse tumour challenge model. PDT was performed by irradiating Radachlorin in C57BL/6 mice transplanted with TC‐1 cells. PDT plus AdmIL‐12 treatment for tumour suppression as well as specific immune responses were evaluated with the following tests: in vitro and in vivo tumour growth inhibition, interferon‐γ (IFN‐γ) and tumour necrosis factor‐α (TNF‐α) assay, and cytotoxic T lymphocyte (CTL) assay. Direct intratumoral injection of AdmIL‐12 resulted in a significant suppression of tumour growth compared to the control group. Treatment of PDT along with AdmIL‐12 further enhanced antitumour effects significantly higher than either AdmIL‐12 or PDT alone. This combined treatment resulted in complete regression of 9‐mm sized tumour in every animal. We also evaluated immune responses induced by these treatments. Combined treatment significantly increased the production level of IFN‐γ and TNF‐α compared with that by AdmIL‐12 or PDT alone. PDT plus AdmIL‐12 enhanced antitumour immunity through increased expansion of the CTL subset mediated by CD8+ T cells. Taken together, these results indicate that the high anti‐cancer activity of PDT with AdmIL‐12 is a powerful tool against cancer therapy and is a promising subject for further investigation.

Cell Cycle Regulatory Protein Expression Profiles by Adenovirus p53 Infection in Human Papilloma Virus-associated Cervical Cancer Cells

PURPOSE The tumor suppressor gene, p53, has been established as an essential component for the suppression of tumor cell growth. In this study, we investigated the time-course anticancer effects of adenoviral p53 (Adp53) infection on human ovarian cancer cells to provide insight into the molecular-level understanding of the growth suppression mechanisms involved in Adp53-mediated apoptosis and cell cycle arrest. MATERIALS AND METHODS Three human cervical cancer cell lines (SiHa, CaSki, HeLa and HT3) were used. The effect of Adp53 infection was studied via cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay. RESULTS Adp53 exerts a significant role in suppressing cervical cancer cell growth. Adp53 also showed growth inhibitory effects in each cell line, and it induced apoptosis and cell cycle arrest. Adp53 differentially regulated the expression of genes and proteins, and the gene expression profiles in the SiHa cells revealed that the p21, p53 and mdm2 expressions were significantly up-regulated at 24 and 48 hr. Western blot shows that the p21 and p53 expression-levels were significantly increased after Adp53 infection. In addition, in all cell lines, both the CDK4 and PCNA protein expression levels were decreased 48 h after Adp53 infection. Cell cycle arrest at the G1 phase was induced only in the SiHa and HeLa cells, suggesting that exogenous infection of Adp53 in cancer cells was significantly different from the other HPV-associated cervical cancer cells. CONCLUSION Adp53 can inhibit cervical cancer cell growth through induction of apoptosis and cell cycle arrest, as well as through the regulation of the cell cycle-related proteins. The Adp53-mediated apoptosis can be employed as an advanced strategy for developing preferential tumor cell-specific delivery.

Tetraarsenic Oxide-mediated Apoptosis in a Cervical Cancer Cell Line, SiHa

PURPOSE Diarsenic oxide, As(2)O(3), has been reported to be effective in treating acute leukemia, and induce apoptosis in many tumor cells. In this study, the ability of a novel arsenical compound, As(4)O(6) (tetraarsenic oxide), along with As(2)O(3), for its ability to induce cell growth inhibition, as well as apoptosis, in human cervical cancer cells, SiHa cells, were evaluated in vitro. MATERIALS AND METHODS To examine the levels of apoptosis, SiHa cells were given two sensitive doses, 0.5 and 1 microM, of arsenical compounds, and a DNA fragmentation assay and FACS analysis were then conducted. In addition, a Western blotting assay was performed to identify target molecules for apoptosis. RESULTS Both As(2)O(3) and As(4)O(6) induced dosedependent inhibition of SiHa cell proliferation. In particular, As(4)O(6) was more effective at suppressing SiHa cell growth than As(2)O(3). In parallel with the inhibition of cell proliferation, As(4)O(6) caused a significantly greater increase in the sub-G1 cell population than As(2)O(3), as determined by propidium iodide DNA staining. This was confirmed by a DNA fragmentation assay and annexin V staining. The Western blotting analysis also showed that the expression of proliferating cell nuclear antigen (PCNA) was suppressed to a significantly greater extent by As(4)O(6) than As(2)O(3) at a dose of 0.5 microM. However, the apoptosis-related protein, Bax, was expressed to a significantly greater extent due to As(4)O(6) than As(2)O(3). CONCLUSION Taken together, these findings suggest that a novel arsenic compound, As(4)O(6), possesses more potent anti-proliferative effects on human cervical cancer cells, with the induction of apoptosis also, at least via the activation of Bax protein in vitro.

Photodynamic effects of Radachlorin® on cervical cancer model

Photodynamic therapy (PDT) has been reported to be effective for treating various tumors and induce apoptosis in many tumor cells. In this study, we examined a biological significance of PDT with a chlorin-based photosensitizer, Radachlorin®, in a cervical cancer model, TC-1 cells. When TC-1 cells were exposed to varied doses of Radachlorin® with light irradiation (6.25 J/cm2), PDT induced a dose-dependent growth inhibition of TC-1 cells. All of these cells were significantly damaged after light irradiation and categorized to be early and late apoptosis, as determined by annexin V staining. Radachlorin® localized primarily into the Golgi apparatus of cells in 12 h of the treatment, and weak fluorescence intensity was also detected in mitochondria. On the other hand, in the in vivo experiments, following light irradiation (100 J/cm2), retarded tumor growth was significant in mice treated with Radachlorin®, as compared to the control group. Taken together, we propose that PDT after the application of Radachlorin® may induce the Golgi apparatus-mediated apoptosis of cervical cancer cells in vitro, and also be effective in the mice system.

Retraction: tetraarsenic oxide-mediated apoptosis in a cervical cancer cell line, SiHa.

Published: Cancer Res Treat. 2005;37(5):307-312 All authors unanimously wish to retract this paper as soon as possible. We deeply apologize to the readers for any inconvenience caused by this retraction.