Runt related transcription factor-1 plays a central role in vessel co-option of colorectal cancer liver metastases

Abstract

Colorectal cancer liver metastasis (CRCLM) has two major histopathological growth patterns: angiogenic desmoplastic and non-angiogenic replacement. The replacement lesions obtain their blood supply through vessel co-option, wherein the cancer cells hijack pre-existing blood vessels of the surrounding liver tissue. Consequentially, anti-angiogenic therapies are less efficacious in CRCLM patients with replacement lesions. However, the mechanisms which drive vessel co-option in the replacement lesions are unknown. Here, we show that Runt Related Transcription Factor-1 (RUNX1) overexpression in the cancer cells of the replacement lesions drives cancer cell motility via ARP2/3 to achieve vessel co-option. Furthermore, overexpression of RUNX1 in the cancer cells is mediated by Transforming Growth Factor Beta-1 (TGFβ1) and thrombospondin 1 (TSP1). Importantly, RUNX1 knockdown impaired the metastatic capability of colorectal cancer cells in vivo and induced the development of angiogenic lesions in liver. Our results confirm that RUNX1 may be a potential target to overcome vessel co-option in CRCLM.

Cancer Cells Promote Phenotypic Alterations in Hepatocytes at the Edge of Cancer Cell Nests to Facilitate Vessel Co-Option Establishment in Colorectal Cancer Liver Metastases

“…Indirect coculturing was performed with 6-well inserts (Falcon, Glendale, AZ, USA, #353090) and companion plates (Falcon, Glendale, AZ, USA, #353502) as described previously [ 32 ]. The cells were seeded in DMEM supplemented with 10% FBS and 1× penicillin/streptomycin overnight.…”

“…The treatment of IHH cells with recombinant TGFβ1 was performed as published previously [ 32 ]. Briefly, the IHH cells were grown as mentioned above.…”

“…The lentiviral vectors were produced in 293T cells using the calcium phosphate method [ 32 , 35 ]. We used the following constructs: Scrambled shRNA#: SHC016, RUNX1#1: TRCN0000338428.…”

“…We performed immunofluorescent (IF) staining for specimens as described previously [ 32 ]. In brief, the sections were deparaffinized with xylene (Leica, #3803665), hydrated with ethanol (Comalc, #P016EAAN), as well as distilled water.…”

“…Indeed, EMT plays an important role in promoting cancer cell motility [ 30 , 31 ]. We recently demonstrated the upregulation of EMT and motility biomarkers in the cancer cells of vessel co-opting CRCLM lesions, which correlated with the upregulation of transforming growth factor beta 1 (TGFβ1) in their proximate liver parenchyma [ 32 ]. It is worth mentioning that the role of EMT in the cells of the organ that hosts tumours is poorly investigated.…”