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Decreased FANCJ caused by 5FU contributes to the increased sensitivity to oxaliplatin in gastric cancer cells.

Mori R, Yoshida K, Tanahashi T, Yawata K, Kato J, Okumura N, Tsutani Y, Okada M, Oue N, Yasui W - Gastric Cancer (2012)

Bottom Line: Oxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer.In MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects.However, these findings were not observed in MKN45/F2R 5FU-resistant cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgical Oncology, Gifu University, Graduate School of Medicine, 1-1 Yanagido, Gifu, Gifu, 501-1194, Japan.

ABSTRACT

Background: Oxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer. The FANCJ protein is one of the Fanconi anemia (FA) gene products, and its interaction with the tumor suppressor BRCA1 is required for DNA double-strand break (DSB) repair. FANCJ also functions in interstrand crosslinks (ICLs) repair by linking to mismatch repair protein complex MLH1-PMS2 (MutLα). While oxaliplatin causes ICLs, 5FU is considered to cause DSBs. Therefore, we investigated the importance of FANCJ in the synergistic effects of oxaliplatin and 5FU in MKN45 gastric cancer cells and the derived 5FU-resistant cell line, MKN45/F2R.

Methods: MKN1, TMK1, MKN45, and MKN45/F2R (5FU-resistant) gastric cancer cells were treated with 5FU and/or oxaliplatin. The signaling pathway was evaluated by a western blotting analysis and reverse transcription polymerase chain reaction (RT-PCR). Drug resistance was evaluated by the 3-(4,5-dimethyl-2-tetrazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay.

Results: In MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects. DSBs appeared when the cells were treated with 5FU. FANCJ was down-regulated, and BRCA1 was induced in a dose- and time-dependent manner. MKN45 cells showed increased sensitivity to oxaliplatin when FANCJ was knocked down by short interfering (si) RNA. However, these findings were not observed in MKN45/F2R 5FU-resistant cells.

Conclusion: These results strongly suggest that the decrease in FANCJ caused by 5FU treatment leads to an increase in sensitivity to oxaliplatin, thus indicating that the FANCJ protein plays an important role in the synergism of the combination of 5FU and oxaliplatin.

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Changes in interstrand crosslink (ICL) repair proteins after 5FU treatment. a The results of a western blotting analysis of the expression of FANCJ, BRCA1, MLH1, PMS2, FANCD2, and FANCD1/BRCA2 in MKN45 cells treated with 5FU at 1, 10, and 100 μM for 24 h. b The results of the western blotting analysis of FANCJ and BRCA1 in MKN1 cells. c The results of the western blotting analysis in TMK1 cells. d The results of the western blotting analysis in MKN45/F2R cells. e The results of the western blotting analysis of the expression of FANCJ and BRCA1 in MKN45 cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h. f The results of the western blotting analysis of the expression of these proteins in MKN45/F2R cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h
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Fig2: Changes in interstrand crosslink (ICL) repair proteins after 5FU treatment. a The results of a western blotting analysis of the expression of FANCJ, BRCA1, MLH1, PMS2, FANCD2, and FANCD1/BRCA2 in MKN45 cells treated with 5FU at 1, 10, and 100 μM for 24 h. b The results of the western blotting analysis of FANCJ and BRCA1 in MKN1 cells. c The results of the western blotting analysis in TMK1 cells. d The results of the western blotting analysis in MKN45/F2R cells. e The results of the western blotting analysis of the expression of FANCJ and BRCA1 in MKN45 cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h. f The results of the western blotting analysis of the expression of these proteins in MKN45/F2R cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h

Mentions: We also examined the expressions of FANCJ and BRCA1 in other gastric cancer cell lines, such as MKN1, TMK1, and MKN45/F2R cells. As shown in Fig. 2b–d. The downregulation of FANCJ was reproduced in MKN1 and TMK1 cells, and induction of BRCA1 was also observed in MKN1 cells. In the MKN45/F2R cells, both FANCJ and BRCA1 were unchanged after 5FU treatment.Fig. 2


Decreased FANCJ caused by 5FU contributes to the increased sensitivity to oxaliplatin in gastric cancer cells.

Mori R, Yoshida K, Tanahashi T, Yawata K, Kato J, Okumura N, Tsutani Y, Okada M, Oue N, Yasui W - Gastric Cancer (2012)

Changes in interstrand crosslink (ICL) repair proteins after 5FU treatment. a The results of a western blotting analysis of the expression of FANCJ, BRCA1, MLH1, PMS2, FANCD2, and FANCD1/BRCA2 in MKN45 cells treated with 5FU at 1, 10, and 100 μM for 24 h. b The results of the western blotting analysis of FANCJ and BRCA1 in MKN1 cells. c The results of the western blotting analysis in TMK1 cells. d The results of the western blotting analysis in MKN45/F2R cells. e The results of the western blotting analysis of the expression of FANCJ and BRCA1 in MKN45 cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h. f The results of the western blotting analysis of the expression of these proteins in MKN45/F2R cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713262&req=5

Fig2: Changes in interstrand crosslink (ICL) repair proteins after 5FU treatment. a The results of a western blotting analysis of the expression of FANCJ, BRCA1, MLH1, PMS2, FANCD2, and FANCD1/BRCA2 in MKN45 cells treated with 5FU at 1, 10, and 100 μM for 24 h. b The results of the western blotting analysis of FANCJ and BRCA1 in MKN1 cells. c The results of the western blotting analysis in TMK1 cells. d The results of the western blotting analysis in MKN45/F2R cells. e The results of the western blotting analysis of the expression of FANCJ and BRCA1 in MKN45 cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h. f The results of the western blotting analysis of the expression of these proteins in MKN45/F2R cells treated with 10 μM of 5FU for 3, 6, 12, and 24 h
Mentions: We also examined the expressions of FANCJ and BRCA1 in other gastric cancer cell lines, such as MKN1, TMK1, and MKN45/F2R cells. As shown in Fig. 2b–d. The downregulation of FANCJ was reproduced in MKN1 and TMK1 cells, and induction of BRCA1 was also observed in MKN1 cells. In the MKN45/F2R cells, both FANCJ and BRCA1 were unchanged after 5FU treatment.Fig. 2

Bottom Line: Oxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer.In MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects.However, these findings were not observed in MKN45/F2R 5FU-resistant cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgical Oncology, Gifu University, Graduate School of Medicine, 1-1 Yanagido, Gifu, Gifu, 501-1194, Japan.

ABSTRACT

Background: Oxaliplatin is effective against many types of cancer, and the combination of 5-fluorouracil (5FU) and oxaliplatin is synergistically effective against gastric cancer, as well as colon cancer. The FANCJ protein is one of the Fanconi anemia (FA) gene products, and its interaction with the tumor suppressor BRCA1 is required for DNA double-strand break (DSB) repair. FANCJ also functions in interstrand crosslinks (ICLs) repair by linking to mismatch repair protein complex MLH1-PMS2 (MutLα). While oxaliplatin causes ICLs, 5FU is considered to cause DSBs. Therefore, we investigated the importance of FANCJ in the synergistic effects of oxaliplatin and 5FU in MKN45 gastric cancer cells and the derived 5FU-resistant cell line, MKN45/F2R.

Methods: MKN1, TMK1, MKN45, and MKN45/F2R (5FU-resistant) gastric cancer cells were treated with 5FU and/or oxaliplatin. The signaling pathway was evaluated by a western blotting analysis and reverse transcription polymerase chain reaction (RT-PCR). Drug resistance was evaluated by the 3-(4,5-dimethyl-2-tetrazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay.

Results: In MKN45 cells, the combination of 5FU and oxaliplatin had synergistic effects. DSBs appeared when the cells were treated with 5FU. FANCJ was down-regulated, and BRCA1 was induced in a dose- and time-dependent manner. MKN45 cells showed increased sensitivity to oxaliplatin when FANCJ was knocked down by short interfering (si) RNA. However, these findings were not observed in MKN45/F2R 5FU-resistant cells.

Conclusion: These results strongly suggest that the decrease in FANCJ caused by 5FU treatment leads to an increase in sensitivity to oxaliplatin, thus indicating that the FANCJ protein plays an important role in the synergism of the combination of 5FU and oxaliplatin.

Show MeSH
Related in: MedlinePlus