title: Immunoglobulin kappa and immunoglobulin lambda are required for expression of the anti-apoptotic molecule Bcl-xL in human colorectal cancer tissue.
abstract: OBJECTIVE
  Aberrant expression of immunoglobulin (Ig) by cancer cells has been documented in a number of malignant tumors but its biological significance is unclear. Cancer cells overexpress anti-apoptotic molecules such as Bcl-xL. The present study aimed to examine the role of expression of Ig light-chain Igk and Iglambda in maintaining the high levels of Bcl-xL in colorectal cancer cells.
  
  
  METHODS
  Thirty patients with colorectal cancer were recruited to this study. Expression of Igk, Iglambda and Bcl-xL in surgically removed cancer tissue was examined by immunohistochemistry and/or flow cytometry. Using the HT29 cell line as a study platform, RNA interference (RNAi) was employed to knock out the genes of Igk and Iglambda in the cancer cell line; the expression of Bcl-xL in HT29 cells was subsequently analyzed.
  
  
  RESULTS
  Human colorectal cancer cells, but not normal colorectal tissue, expressed both Igk and Iglambda in the cytoplasm. High levels of Bcl-xL were detected in cancer cells. Using RNAi to knock out the genes of Igk and/or Iglambda, Bcl-xL expression in HT29 cells was significantly suppressed and the cells became apoptotic.
  
  
  CONCLUSIONS
  The results suggest that expression of Igk and Iglambda is required to stabilize Bcl-xL expression in cancer cells.
authors.affiliation: Department of Gastroenterology (South Building), China PLA General Hospital, Beijing, PR China.
authors.forename: Shao-Bo
authors.initials: SB
authors.lastname: Yang
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.forename: Ben-Yan
authors.initials: BY
authors.lastname: Wu
authors.forename: Meng-Wei
authors.initials: MW
authors.lastname: Wang
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Cai
authors.forename: Dan-Bi
authors.initials: DB
authors.lastname: Cho
authors.forename: Jasmine
authors.initials: J
authors.lastname: Chong
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Shang-Guo
authors.initials: SG
authors.lastname: Tang
authors.forename: Ping-Chang
authors.initials: PC
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007146:Immunoglobulin lambda-Chains / Q000235:genetics / Q000378:metabolism*; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D007155:Immunologic Factors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C494811:BCL2L1 protein, human; D014408:Biomarkers, Tumor; C014609:IgK; D007146:Immunoglobulin lambda-Chains; D007136:Immunoglobulins; D007155:Immunologic Factors; D051020:bcl-X Protein