title: Overcoming antiapoptotic responses to promote chemosensitivity in metastatic colorectal cancer to the liver.
abstract: BACKGROUND
  Metastatic colon cancer is highly resistant to chemotherapy. A variety of mechanisms by which cancer cells resist chemotherapy have been described including enhanced export of drug from cancer cells and alterations in drug metabolism. In addition, the response of cancer cells to genotoxic therapies may be diminished by acquired defects in either the response mechanisms to DNA damage or cell cycle regulatory pathways. Recently, attention has focused on mechanisms that are activated by treatment exposure and subsequently promote resistance by rescuing cancer cells from apoptosis. The objective of this review is to examine the role of antiapoptotic mechanisms of chemotherapy resistance and to determine the potential utility of therapeutic strategies that target these mechanisms.
  
  
  METHODS
  To accomplish the objectives, a brief overview of mechanisms of chemotherapy resistance is provided. The concept of inducible chemotherapy resistance is introduced by examination of a specific antiapoptotic mechanism, mediated by the transcription factor, nuclear factor kappa B (NF-kappa B). The ability to use inhibitors of NF-kappa B to promote chemosensitivity is examined in vitro and in vivo.
  
  
  RESULTS
  Inhibition of chemotherapy-induced NF-kappa B activation enhances apoptosis and augments chemotherapy sensitivity.
  
  
  CONCLUSIONS
  NF-kappa B inhibition may overcome cancer cell defense against apoptosis. Molecular therapies that target this resistance mechanism may be useful adjuncts to conventional chemotherapy.
authors.affiliation: Division of Surgical Oncology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA. jcusack@partners.org
authors.forename: James C
authors.initials: JC
authors.lastname: Cusack
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015179:Colorectal Neoplasms / Q000473:pathology*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000556:secondary*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D016328:NF-kappa B