title: P-glycoprotein expression and chemosensitivity in highly purified fresh human gastrointestinal cancer cells.
abstract: OBJECTIVE
  Colorectal cancer is one of the tumors most refractory to treatment by chemotherapy. One of the major problems associated with cancer chemotherapy is drug-resistance of tumor cells, and resistance to doxorubicin (DOX) is mainly due to the effect of P-glycoprotein. We have tried to prove the correlation between P-glycoprotein expression and DOX-sensitivity in highly purified fresh human colorectal cancer and, moreover, to prove the differentiation of P-glycoprotein expression between the different kinds of cancers, including gastric cancer.
  
  
  METHODS
  The present study was designed to quantify P-glycoprotein expression by flow cytometry, and DOX-sensitivity by MTT assay in highly purified fresh human tumor cells obtained from 29 cancer patients including 13 colorectal cancers and 16 gastric cancers.
  
  
  RESULTS
  DOX-sensitivity decreased in proportion to P-glycoprotein expression in colorectal cancer. P-glycoprotein expression in colorectal cancer was higher than that in gastric cancer. Particularly, P-glycoprotein expression in colorectal cancer in the DOX low-sensitivity group was higher than in the DOX high-sensitivity group.
  
  
  CONCLUSIONS
  The chemotherapeutic management of patients with colorectal cancer might be more effective if we can circumvent the effect of P-glycoprotein.
authors.affiliation: Second Department of Surgery, Wakayama Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hotta
authors.forename: H
authors.initials: H
authors.lastname: Tanimura
authors.forename: T
authors.initials: T
authors.lastname: Tsunoda
authors.forename: M
authors.initials: M
authors.lastname: Iwahashi
authors.forename: M
authors.initials: M
authors.lastname: Tani
authors.forename: K
authors.initials: K
authors.lastname: Noguchi
authors.forename: S
authors.initials: S
authors.lastname: Mizobata
authors.forename: K
authors.initials: K
authors.lastname: Arii
authors.forename: H
authors.initials: H
authors.lastname: Terasawa
authors.forename: M
authors.initials: M
authors.lastname: Nakamori
authors.forename: H
authors.initials: H
authors.lastname: Yamaue
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D006801:Humans; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin