APE/Ref-1 deficiency inhibits cellular transformation and metastatic potential of human melanoma cells

Abstracts PP22-2 Increased caspase-2 activity is associated with induction of apoptosis in IFN-b sensitive mela- noma cell lines Takafumi Kamiya 1 , Tamaki Okabayashi 2 , Shin-ichi Yokota 2 , Jiro Ogino 2 , Toshiharu Yamashita 1 , Nobuhiro Fujii 2 , Kowichi Jimbow 1 Department of Dermatology, Sapporo Medical University School of Medicine, Sapporo, Japan, 2 Depatment of Microbiol- ogy, Sapporo Medical University School of Medicine, Sapporo, Japan Interferon (IFN) is believed to be one of the most effective anti- melanoma agents. Specifically, IFN-b has the ability to induce apoptosis of melanoma cells. Induction of tumor necrosis factor- related apoptosis-inducing ligand (TRAIL) has also been sug- gested to have a critical role in IFN-b-mediated apoptosis. To characterize the signaling pathway involved in IFN-b-mediated apoptosis, we analyzed the biological effect of IFN-b on the cell death and caspase activation of melanoma cells. Among four human melanoma cell lines tested, MM418, SK-mel-23 and SK- mel-118 showed inhibition of cell viability, increased apoptotic populations and upregulation of caspase-3 activity by IFN-b. Furthermore, caspase-2 activity was upregulated in all the IFN-b- sensitive cell lines, although MM418, which is IFN-b sensitive, did not show induction of TRAIL mRNA by IFN-b. On the other hand, G361 was not affected by IFN-b. However, IFN-b pretreatment significantly increased the sensitivity against exogenous TRAIL-mediated apoptosis and activation of cas- pase-2 in G361, which is resistant to IFN-b-induced apoptosis. Caspase-2 activation is commonly associated with induction of apoptosis in IFN-b-sensitive melanoma cells. PP23-1 Improvement in detection of micrometastasis in melanoma patients sentinel lymph nodes using anti-HMW-MAA antibodies Yasufumi Goto 1 , Soldano Ferrone 2 , Takaaki Arigami 3 , Atsushi Tanemura 3 , Donald L. Morton 4 , Dave S.B. Hoon 3 Department of Dermatology, Shinshu U. School of Medicine, Matsumoto, Japan, 2 Hillman Cancer Research Center, U. of Pittsburg, Pittsburgh, PA, USA, 3 Department of Molecular Oncology, John Wayne Cancer Institute, Santa Monica, CA, USA, 4 Division of Surgical Oncology, John Wayne Cancer Institute Detection of micrometastasis in sentinel lymph nodes (SLNs) is important for staging, prognosis, and disease management in melanoma patients. Immunohistochemical staining (IHC) using anti-S-100p, -HMB-45, and -MART-1 antibodies (Abs) are used for detecting metastatic melanoma in SLNs. However, current IHC techniques may fail to detect all clinically significant nodal micrometastases in melanoma patients. In this study, we used a Human High Molecular Weight Melanoma-Associated Antigen (HMW-MAA)-specific monoclonal Abs (mAb) for detection of micrometastatic melanoma in SLNs. Moreover we assessed HMW-MAA as quantitative real-time RT-PCR (qRT) biomarkers for detection of nodal metastasis in melanoma. Paraffin- embedded archival tissue (PEAT) specimens were obtained from 42 non-SLN macrometastases, 10 SLN macrometastases, 32 SLN micrometastases, and 16 tumor-negative SLNs of 100 SLN melanoma patients. Frequency and staining intensity of IHC were significantly higher for HMW-MAA than for MART-1 in nodal macrometastases (P<0.0001 and P<0.0001, respectively) and micrometastases (P<0.0001 and P=0.004, respectively). In a comparison analysis, 23 of 23 (100%) micrometastases were positive with HMW-MAA mAbs, whereas 21 (91%) and 18 (78%) specimens stained positive with S-100p polyclonal Ab and HMB-45 mAb, respectively. qRT analysis of 48 nodal metastases identified 32 (67%) SLNs that expressed HMW-MAA, 31 (65%) that expressed MART-1, and 39 (81%) that expressed both markers. HMW-MAA is more sensitive and specific than MART- 1 for IHC-based detection of SLN micrometastases. SLN PEAT- based detection specificity of melanoma micrometastases can be improved by IHC with HMW-MAA mAbs. Moreover, HMW- MAA mRNA expression has potential utility for qRT assessment of occult metastatic melanoma in lymph nodes. The study demonstrates HMW-MAA expression as a biomarker for micro- metastasis detection in lymph nodes is a significant improve- ment over current conventional IHC approaches. PP24-1 Common melanocytic nevi in 7-year old schoolchildren residing at different latitudes in Sweden Ylva E. Rodvall 1 , Henrik Ulle ´ n 2 , Carl-Fredrik Wahlgren 3 , Kerstin E. Wiklund 4 Department of Occupational and Environmental Health, Stock- holm County Council, Stockholm, Sweden, 2 Karolinska Hospital, Karolinska Institutet, Stockholm Sweden, 3 Department of Med- icine, Karolinska Institutet, Stockholm, Sweden, 4 Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden Background: Studies of the epidemiology of common melano- cytic nevi (CMN) have the potential to shed light on the etiology of melanoma. The incidence of cutaneous malignant melanoma (CMM) in the north of Sweden is half of that in the south. Objective: The aim was to investigate the number of CMN in relation to body sites among children and to compare residing at different latitudes. Material & methods: Municipalities were chosen at latitude 65-68N in the north of Sweden and two at latitude 57N in the south. Children born in 1994 and registered in the municipalities were to be included (N=1676). A questionnaire was sent to their parents, asking about the child’s tanning habits. Of the children, 1380 (82.3%) had a full body examination for CMN 2 mm or larger excluding the genital area and the scalp. Results: For all examined body sites CMN was significantly less prevalent among children living at latitude 65N (inland), with mean number of nevi per square meter body surface area of 5.6 (95% CI:4.8-6.5), than among those living at latitude 57N (coastal), with mean values 10.4 (CI:8.9-12.0). Also blond hair, blue/green eyes, holidays at seaside resorts abroad, more frequent sunburns, and parents fancying tanning, were signifi- cant predictors of large numbers of CMN. CMN were more frequent in intermittent exposed body sites compared to chronic and rare exposed sites. At latitude 57 N (costal) with mean values 14.7 (CI:12.6-17.2), 12.0 (CI:8.8-16.2) and 6.5 (CI:5.2-8.2) respectively. Conclusion: These findings support previous evidence that the development of CMN is related to the level of sun exposure in childhood expressed as latitude of residence. This relation remained statistically significant after adjustment for the effects of other factors that were related to CMN numbers. The localization of CMN is the same as the localization of CMM. To reduce the incidence of CMM, a change in attitudes and behavior must start with young children and their parents. PP24-2 APE/Ref-1 deficiency inhibits cellular transformation and metastatic potential of human melanoma cells Sun Yang 1 , Bobbye Misner 1 , Rita Chiu 1 , Frank L. Meyskens, Jr. 1,2* Departments of Medicine (Hematology/Oncolgoy Division) and Biological Chemistry, Chao Family Comprehensive Cancer Center, School of Medicine, University of California Irvine, Orange, California 92868, USA a 2008 The Authors, Journal Compilation a 2008 Blackwell Munksgaard