Suppression of Colorectal Cancer Liver Metastasis and Extension of Survival by Expression of Apolipoprotein(a) Kringles

Abstract

The formation of hepatic metastases in colorectal cancer is the main cause of patient death. Current therapies directed at hepatic metastasis of colorectal cancer have had minimal impact on outcome. Therefore, alternative treatment strategies for liver metastasis require development. The present study was performed to evaluate the application of cDNA of LK68 encoding apolipoprotein(a) kringles IV-9, IV-10, and V as possible candidates for gene therapy treatment of this life-threatening disease. The murine colorectal cancer cell line CT26 was transduced ex vivo with LK68 cDNA via retroviral gene transfer, and an experimental model of hepatic metastasis was established by injecting LK68-expressing and control cells into the spleens of BALB/c mice. Expression of LK68 did not affect the growth characteristics and viability of transduced CT26 cells in vitro. LK68 produced from CT26 cells substantially inhibited the migration of endothelial cells in vitro. In vivo, substantial suppression of liver metastasis and prolonged survival were observed in mice bearing LK68-expressing CT26 cells, compared with controls. LK68-expressing liver metastases were restricted to smaller sizes and displayed decreased microvessel density and increased tumor cell apoptosis. Our data collectively indicate that LK68 suppresses angiogenesis-dependent progression of prevascular micrometastases to macroscopic tumors and their growth, which are clinically accessible and biologically relevant therapeutic targets. We propose that antiangiogenic gene therapy with LK68 is a promising strategy for the treatment of colorectal cancer liver metastasis.

Adeno-associated virus-mediated expression of apolipoprotein (a) kringles suppresses hepatocellular carcinoma growth in mice

“…At the protein level, Kim et al 10 and Yu et al 11,12 demonstrated that the vascularity in LK68-treated tumor tissues was greatly reduced, and the expression of angiogenin, VEGF, and basic fibroblast growth factor (bFGF), which switch on the angiogenic phenotype in tumor tissues, was dramatically decreased at peripheral regions of the tumors. Similarly, LK8 was found to inhibit the migration of HUVECs in a dose-dependent manner in vitro and new capillary formation in vivo.…”

“…Proliferation inhibition and wound migration assays were performed as previously described in detail elswhere. 11,24 Animals. Five-week-old male BALB/c nu/nu mice (Charles River, Yokohama, Japan) were housed in a sterile environment.…”

“…The molecular mass of LK68 produced in HEK 293 cells was almost identical to that of LK68 from CHO cells and from murine CT26 cells. 11,15 Inhibition of Endothelial Cell Proliferation and Migration In Vitro by LKs. We first examined the ability of rAAV-produced LKs to inhibit proliferation of HUVECs.…”

“…LK68-expressing murine colorectal cancer cells (CT26) restricted hepatic metastases to smaller sizes, prevented peritoneal dissemination, and significantly suppressed colon tumor growth in different experimental models. 11,12 These investigators also demonstrated that apo(a) kringle KV, also referred to as LK8, inhibits the migration of HUVECs in a dose-dependent manner, and inhibits new capillary formation in vivo. 13 However, anti-angiogenic cancer therapy requires long-term administration of relatively high concentrations of anti-angiogenic proteins to ensure tumor growth suppression in vivo.…”

Macrophage metalloelastase (MME) as adjuvant for intra-tumoral injection of oncolytic adenovirus and its influence on metastases development

“…28 Briefly, 125-day-old female SCID mice were anesthetized with a ketamine (Ketaminol 75 mg kg À1 ; Intervet, Boxmeer, the Netherlands)/dexmedetomidine (Dexdormitor 1 mg kg À1 ; Orion Pharm., Espoo, Finland) admixture and the spleen was exteriorized through a left lateral flank incision. Tumors were established by intrasplenic injection of 1 Â 10e6 HT29 cells as described earlier.…”