ABSTRACT
It has been widely reported that patient-derived tumor xenografts (PDXs) are more similar to tumor tissues than conventional cancer cell lines. Kinetochore-associated protein 2 (KNTC2) is known to be upregulated specifically in tumor tissues of cancer patients and is recognized as a potential target for cancer therapy. Previously, in vivo antitumor activities of KNTC2 short interfering RNA encapsulated into a lipid nanoparticle (KNTC2-LNP) were reported in orthotopic hepatocellular carcinoma mouse models. However, it remains unclear whether KNTC2-LNP exhibits antitumor activities against lung cancer PDXs. In the present study, the antitumor activities of KNTC2-LNP were clarified in a three-dimensional culture system and a subcutaneous tumor model of lung cancer PDX, LC-60, which was resistant to erlotinib. Growth inhibitory activities of KNTC2-LNP were associated with knockdown activities. Furthermore, KNTC2-LNP also exhibited in vivo antitumor activity against another lung cancer PDX, LC-45, which was sensitive to erlotinib. These results suggest that KNTC2 is a promising target for patients with lung cancer.
ABSTRACT
Hepatocellular carcinoma (HCC) is still one of the major causes of cancer-related death. Kinetochore-associated protein 2 (KNTC2) is specifically upregulated in tumor tissues of HCC patients and recognized as a potential candidate target for the treatment of HCC. However, the relationship between KNTC2 and in vivo tumor growth of HCC is not yet fully understood. Here we encapsulated KNTC2 siRNAs into a lipid nanoparticle (LNP) and investigated their knockdown activity, target engagement marker, anti-tumor activity and hepatotoxicity in an orthotopic HCC model mice of Hep3B-luc cells. Single i.v. administration of KNTC2 siRNA-LNP specifically suppressed the expression levels of both human KNTC2 mRNA and mouse Kntc2 mRNA in tumor tissues. Phosphorylation levels of histone H3 (HH3) at serine 10 in tumor tissues were increased by KNTC2 siRNA-LNP. Repeated administration of KNTC2 siRNA-LNP (twice a week) specifically inhibited the growth of tumor tissues without increasing the plasma AST and ALT levels. Their growth inhibitory activities were consistent with knockdown activities. These data strongly indicated that KNTC2 is a promising target for the treatment of HCC and that phosphorylated HH3 at serine 10 is one of the target engagement markers for KNTC2.
Subject(s)
Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/therapy , Genetic Therapy/methods , Liver Neoplasms/genetics , Liver Neoplasms/therapy , Nuclear Proteins/genetics , RNA, Small Interfering/administration & dosage , Animals , Antineoplastic Agents/administration & dosage , Apoptosis/drug effects , Apoptosis/genetics , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/genetics , Cytoskeletal Proteins , Gene Knockdown Techniques/methods , Humans , Liver Neoplasms/pathology , Male , Mice , Mice, SCID , Molecular Targeted Therapy/methods , Treatment OutcomeABSTRACT
Despite considerable efforts to develop efficient carriers, the major target organ of short-interfering RNAs (siRNAs) remains limited to the liver. Expanding the application outside the liver is required to increase the value of siRNAs. Here we report on a novel platform targeted to muscular organs by conjugation of siRNAs with anti-CD71 Fab' fragment. This conjugate showed durable gene-silencing in the heart and skeletal muscle for one month after intravenous administration in normal mice. In particular, 1µg siRNA conjugate showed significant gene-silencing in the gastrocnemius when injected intramuscularly. In a mouse model of peripheral artery disease, the treatment with myostatin-targeting siRNA conjugate by intramuscular injection resulted in significant silencing of myostatin and hypertrophy of the gastrocnemius, which was translated into the recovery of running performance. These data demonstrate the utility of antibody conjugation for siRNA delivery and the therapeutic potential for muscular diseases.
