Effects of PHA-665752 and Cetuximab Combination Treatment on In Vitro and Murine Xenograft Growth of Human Colorectal Cancer Cells with KRAS or BRAF Mutations.

Abstract

BACKGROUND:

It remains unknown whether blockade of c-Met signaling and epidermal growth factor receptor signaling is effective in suppressing the growth of human colorectal cancer (CRC) cells. In this study, we investigated the effects of the c-Met inhibitor PHA-665752 alone and in combination with cetuximab on the growth of human CRC cells in vitro and in mouse xenografts.

METHODS:

Human CRC cell lines (Caco2, HCT-116, and HT-29) and mice bearing HCT-116 xenografts were treated with cetuximab in the absence or presence of PHA-665752. Cell viability and apoptosis were examined using the MTT and TUNEL assays, respectively. Vimentin was measured by immunohistochemistry as a marker for epithelial-to-mesenchymal transition. Western blotting was used to determine signaling protein expression levels.

RESULTS:

The MTT assay showed that the growth of Caco2, HCT-116, and HT-29 cells was inhibited by PHA-665752 in a dose-dependent manner, but only Caco2 cell growth was suppressed by cetuximab. Combination treatment with PHA-665752 and cetuximab inhibited the proliferation of Caco2 cells and RAS mutant CRC cell lines. However, relative to the PHA-665752-alone treatment group, HT-29 cells with a BRAF mutation showed no noticeable effect. The mean tumor volume in mice treated with cetuximab in combination with PHA-665752 was significantly smaller than that in the mice treated with only cetuximab (P = 0.033) or PHA-665752 (P < 0.01). Similarly, the expression of vimentin in the mice treated with PHA-665752 in combination with cetuximab was significantly lower than that in the mice treated with cetuximab or PHA-665752 alone (P < 0.05 in each case). TUNEL assays revealed that treatment with PHA-665752 in combination with cetuximab markedly increased CRC cell apoptosis. Western blotting analysis of signaling protein expression showed that PHA- 665752 inhibited Met phosphorylation (P < 0.05). In addition, treatment with cetuximab alone or in combination with PHA-665752 effectively inhibited EGFR phosphorylation (P < 0.05).

CONCLUSION:

Combination treatment with PHA-665752 and cetuximab suppressed in vitro and in vivo CRC cell growth more than treatment with either agent alone did.

• Authors: Yi-Tao Jia, Dong-Hai Yang, Zhaolong Zhao, Xiao-Hui Bi, Wei-Hua Han, Bo Feng, Jie Zhi, Bin Gu, Zhihui Duan, Jian-Hua Wu, Ying-Chao Ju, Ming-Xia Wang, Zhong-Xin Li
• Journal: Current cancer drug targets (Curr Cancer Drug Targets) Vol. 18 Issue 3 Pg. 278-286 ( 2018) ISSN: 1873-5576 [Electronic] Netherlands
• PMID: 28359236 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright© Bentham Science Publishers; For any queries, please email at [email protected].

Chemical References

• 5-((2,6-dichlorobenzyl)sulfonyl)-3-((3,5-dimethyl-4-((2-(pyrrolidin-1-ylmethyl)pyrrolidin-1-yl)carbonyl)-1H-pyrrol-2-yl)methylene)-1,3-dihydro-2H-indol-2-one
• Indoles
• KRAS protein, human
• Sulfones
• BRAF protein, human
• Proto-Oncogene Proteins B-raf
• Proto-Oncogene Proteins p21(ras)
• Cetuximab

Topics

• Animals
• Antineoplastic Combined Chemotherapy Protocols (pharmacology)
• Apoptosis
• Cell Proliferation
• Cetuximab (administration & dosage)
• Colorectal Neoplasms (drug therapy, genetics, pathology)
• Humans
• In Vitro Techniques
• Indoles (administration & dosage)
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Mutation
• Proto-Oncogene Proteins B-raf (genetics)
• Proto-Oncogene Proteins p21(ras) (genetics)
• Sulfones (administration & dosage)
• Tumor Cells, Cultured
• Xenograft Model Antitumor Assays