Establishment of Perineural Invasion Models and Analysis of Gene Expression Revealed an Invariant Chain (CD74) as a Possible Molecule Involved in Perineural Invasion in Pancreatic Cancer NorimasaKoide, 1,5 TaketoYamada, 1 Rie Shibata, 1 TaisukeMori, 1 Mariko Fukuma, 1 KenYamazaki, 1,3 Koichi Aiura, 2 Motohide Shimazu, 2 SetsuoHirohashi, 4 YujiNimura, 5 and Michiie Sakamoto 1 Abstract Purpose: Perineural invasion causes frequent local recurrence even after resection and a poor prognosis for pancreatic cancer. We established perineural invasion models and analyzed the molecularmechanismofperineuralinvasioninpancreaticcancer. Experimental Design: Seven pancreatic cancer cell lines with or without human peripheral nerves were s.c. implanted in nonobese diabetes/severe combined immunodeficient mice.We comparedexpressionprofilesamonghighandlowperineuralinvasioncelllinesbyusinganoligo- nucleotidemicroarray.Weexaminedup-regulationof theinvariantchain(CD74)inhighperineural invasioncelllinesinmRNAandproteinlevelsandsurgicalcasesimmunohistochemically. Results: Four of seven pancreatic cancer cell lines (CaPan1, CaPan2, CFPAC, and MPanc96) showed perineural invasion to s.c. transplanted human peripheral nerves. Moreover, CaPan1and CaPan2(highperineuralinvasiongroup)alsoresultedinahighfrequencyofperineuralinvasionto mouses.c.peripheralnerves,whereasthreepancreaticcancercelllinesHPAFII,AsPC1,andPanc1 (lowperineuralinvasiongroup)didnotshowperineuralinvasiontoeitherhumanormousenerves. Weidentified37up-regulatedgenesand12down-regulatedgenesinthehighperineuralinvasion groupcomparedwiththelowperineuralinvasiongroup.Amongthem,CD74wasup-regulatedin thehighperineuralinvasiongroupinmRNAandproteinlevels.Furthermore,immunohistochemical expression of CD74 in clinical cases revealed its significant overexpression in pancreatic cancer withperineuralinvasion( P < 0.008). Conclusions: Thisisthefirstreportofperineuralinvasionmodelsusinghumanpancreaticcancer cell lines. In combination with gene expression profiling, it was indicated that CD74 could be a candidate molecule involved in perineural invasion.These models provide new approaches for studyofperineuralinvasioninpancreaticcancer. Pancreatic cancer is the fourth leading cause of cancer-related death in the United States (1). Worldwide pancreatic cancer causes an estimated 213,000 deaths a year (2). In the United States, f32,180 patients are diagnosed with pancreatic cancer annually, and nearly an equal number will die from the disease (1). When first diagnosed with pancreatic cancer, about 80% of all patients receive palliative therapy instead of surgery because of locally advanced disease, depending on perineural invasion or metastasis. The remaining 20% of patients receiving surgery still have a poor prognosis due to high incidence and early occurrence of local recurrence and hepatic and lymph node metastasis, even after pathologically curative surgery (3–5). It is suspected that microscopic hepatic metastasis is already present (6). Cancer cells spreading in the perineural space even at an early clinical stage also cause local recurrence in the retroper- itoneum because of residual tumor cells in the perineural space after surgical resection (7). Moreover, many previous clinico- pathologic reports showed that perineural invasion in pancre- atic cancer was one of the most significant poor prognostic factors (8, 9). Genetic alternations seem to be responsible for the develop- ment of pancreatic cancer (10). Recently, pancreatic cancer– specific expression profiles using cDNA microarrays (11–13), Affymetrix gene chip (14, 15), and serial analysis of gene expression (16) have been used by many investigators. However, the molecular mechanisms of hepatic metastasis and perineural invasion in pancreatic cancer are far from clear. Some studies reported metastasis-related genes by analyzing gene expression profiles between a highly metastatic variant and a parental pancreatic cancer cell line in an orthotopic Human Cancer Biology Authors’ Affiliations: Departments of 1 Pathology and 2 Surgery, School of Medicine, Keio University; 3 Genomic Division and 4 Pathology Division, National Cancer Center Research Institute,Tokyo, Japan; and 5 Division of Surgical Oncology,DepartmentofSurgery,NagoyaUniversity,Nagoya,Japan Received8/23/05;revised1/12/06;accepted2/2/06. Grant support: Grant-in-aid for the 21th Century Center of Excellence program and Cancer Research from the Ministry of Education, Culture, Sports, Science and TechnologyofJapan,fortheThirdTermComprehensive10-YearStrategyforCancer Control from the Ministry of Health, Labor andWelfare ofJapan, and for Cancer ResearchfromtheFoundationforPromotionofCancerResearch. Thecostsofpublicationofthisarticleweredefrayedinpartbythepaymentofpage charges.This article must therefore be hereby marked advertisement in accordance with18U.S.C.Section1734solely toindicatethisfact. Requests for reprints: Michiie Sakamoto, Department of Pathology, School of Medicine, Keio University, 35 Shinanomachi, Shinjyuku-ku,Tokyo, 160-8582, Japan. Phone: 81-3-5363-3764; Fax: 81-03-3353-3290; E-mail: msakamot@ sc.itc.keio.ac.jp. F 2006AmericanAssociationforCancerResearch. doi:10.1158/1078-0432.CCR-05-1852 www.aacrjournals.org Clin Cancer Res 2006;12(8) April 15, 2006 2419 Downloaded from http://aacrjournals.org/clincancerres/article-pdf/12/8/2419/1968543/2419.pdf by guest on 20 June 2022