Fatty Acid Dehydratase HACD3 Promotes The Progression Of Colorectal Cancer By Activating CDK2 Pathway

HACD3（3-hydroxyacyl-Co A dehydrate 3）is a member of the HACD（3-hydroxyacyl-Co A dehydrate）family,catalyzes the third of the four reactions of the long-chain fatty acids elongation cycle.Yet HACD3 only shows weak activity in saturated and monounsaturated fatty acid extension pathways,and multi-omics data and text mining predict that HACD3 is closely related to the occurrence and development of a variety of tumors.According to GEPIA database analysis,HACD3 expression in colorectal cancer tissues was more abundant and significantly higher than that of normal intestinal tissues.There were also literature reports that HACD3 is closely related to liver metastasis of colorectal cancer.However,the role and mechanism of HACD3 in the malignant progression of colorectal cancer are still unclear.Objective:We aim to investigate possible role of HACD3 in colorectal cancer（CRC）.Methods:The expression of HACD3 in CRC tissues and cells was detected by RT-PCR,Western Blot and immunohistochemistry（IHC）;Cell proliferation,colony formation,invasion,migration and cell cycle progression are determined in HACD3 knockdown and overexpression CRC cells in vitro;To construct Knockout of Hacd3 and hybridize with Apc^min/+mice to observe the effect of Hacd3 knockout on the progression of disease and survival cycle of Apc^min/+mice;Through phosphorylation proteomics,the target molecules of HACD3 were screened and the interaction between HACD3 and the target molecules was verified;According to the predicted functional domain of HACD3,HACD3 was cut into two segments from the N-terminal,and corresponding truncated plasmids were constructed.The effect of the two truncated plasmids on CRC cells was observed through cell function experiments,and the interaction between the two truncated plasmids and target molecules was verified,and effective truncated plasmids were screened;The screened truncated plasmids were cut from the N-terminal according to the length of 20-30 amino acids,and 11 short peptides were synthesized.Through the cell function test,the cancer promoting functional segment of HACD3 was screened,and its effect on the target molecule was verified,so as to screen the specific functional segment.Results:HACD3 is highly in CRC tissues and cells.In vivo and in vitro;HACD3promotes the malignant progression of CRC cells;Knockout of Hacd3 can slow down the progression of Apc^min/+mice and prolong the life cycle of tumor-bearing mice.HACD3interacts with CDK2 and results in CDK2 T160 phosphorylation through a domain located at amino acid 298-324 of HACD3.Conclusions:Lipid metabolic enzyme HACD3 promotes the progression of CRC by activating CDK2 pathway.Targeted inhibition of the cancer-promoting region of HACD3may become an effective method for the treatment of colorectal cancer.The elucidation of the cancer-promoting mechanism of HACD3 will also open a new perspective for further exploring the new functions of the fatty acid dehydratase HACD family.