The Growth and Metastasis of Human Hepatocellular Carcinoma Xenografts Are Inhibited by Small Interfering RNA Targeting to the Subunit ATP6L of Proton Pump
- 1 August 2005
- journal article
- Published by American Association for Cancer Research (AACR) in Cancer Research
- Vol. 65 (15), 6843-6849
- https://doi.org/10.1158/0008-5472.can-04-3822
Abstract
Extracellular pH is usually low in solid tumors, in contrast to the approximately neutral intracellular pH. V-ATPase, which overly functions in some cancers with metastatic potential, plays an important role in maintaining neutral cytosolic pH, very acidic luminal pH, and acidic extracellular pH. ATP6L, the 16 kDa subunit of proton pump V-ATPase, can provide proton hydrophilic transmembrane path. In this study, ATP6L in a human hepatocellular carcinoma cell line with highly metastatic potential (HCCLM3) was knocked down using DNA vector-based small interfering RNA (siRNA) to suppress the metastasis. The expression of ATP6L in stable siRNA transfectants, designated as si-HCCLM3 cells, was inhibited by approximately 60%. The proton secretion and the intracellular pH recovery from NH4Cl-prepulsed acidification were inhibited in si-HCCLM3 cells. The invasion of the si-HCCLM3 cells was suppressed in vitro; simultaneously, the expressions of matrix metalloproteinase-2 and gelatinase activity were reduced. In vivo, at 35th day after implantation of the si-HCCLM3 xenografts into the livers in BalB/c (nu+/nu+) mice, the size of liver tumor tissues was dramatically smaller in siRNA group than in the controlled group. The most impressing effect of ATP6L siRNA is its striking reduction of the metastatic potential of HCCLM3 cells. In control, all eight mice had the intrahepatic metastasis and six of eight the pulmonary metastasis, whereas in ATP6L siRNA-treated group, three of eight had the intrahepatic metastasis and only one of eight the pulmonary metastasis. The results suggest that the inhibition of V-ATPase function via knockdown of ATP6L expression using RNA interfering technology can effectively retard the cancer growth and suppress the cancer metastasis by the decrease of proton extrusion and the down-regulation of gelatinase activity.Keywords
This publication has 39 references indexed in Scilit:
- Alterations of intracellular pH homeostasis in apoptosis: origins and rolesCell Death & Differentiation, 2004
- Important role for the V-type H+-ATPase and the Golgi apparatus in the recycling of PTH/PTHrP receptorAmerican Journal of Physiology-Endocrinology and Metabolism, 2004
- Vacuolar H+-ATPase Binding to MicrofilamentsJournal of Biological Chemistry, 2004
- Comparison of matrix metalloproteinase expression between primary tumors with or without liver metastasis in pancreatic and colorectal carcinomasJournal of Surgical Oncology, 2002
- The vacuolar (H+)-ATPases — nature's most versatile proton pumpsNature Reviews Molecular Cell Biology, 2002
- Clinical role of MMP‐2/TIMP‐2 imbalance in hepatocellular carcinomaInternational Journal of Cancer, 2001
- Overexpression of Vacuolar ATPase 16-kDa Subunit in 10T1/2 Fibroblasts Enhances Invasion with Concomitant Induction of Matrix Metalloproteinase-2Biochemical and Biophysical Research Communications, 2000
- Binding of human papillomavirus 16 E5 to the 16 kDa subunit c (proteolipid) of the vacuolar H+-ATPase can be dissociated from the E5-mediated epidermal growth factor receptor overactivationOncogene, 2000
- β1 Integrin Binds the 16-kDa Subunit of Vacuolar H+-ATPase at a Site Important for Human Papillomavirus E5 and Platelet-derived Growth Factor SignalingPublished by Elsevier ,1999
- Intracellular pH measurements in Ehrlich ascites tumor cells utilizing spectroscopic probes generated in situBiochemistry, 1979