T. Ohta et al., EXPRESSION OF 16-KDA PROTEOLIPID OF VACUOLAR-TYPE H-ATPASE IN HUMAN PANCREATIC-CANCER(), British Journal of Cancer, 73(12), 1996, pp. 1511-1517
Recent studies have shown that bafilomycin A(1)-sensitive vacuolar-typ
e H+-ATPase (V-ATPase) plays important roles in cell growth and differ
entiation. However, there is no published study that has focused on th
e expression of V-ATPase in human tumour tissues. This study was desig
ned to examine the mRNA and protein levels for the 16 kilodalton (kDa)
proteolipid of V-ATPase in human pancreatic carcinoma tissues. We fir
st investigated the mRNA level for V-ATPase in six cases of invasive p
ancreatic cancers and two normal pancreases, using reverse transcripti
on-polymerase chain reaction technique, Then, we examined immunohistoc
hemically the level of V-ATPase protein in 49 pancreatic cancers and t
en benign cystic neoplasms of the pancreas, using antisera raised agai
nst the 16 kDa proteolipid. There was a notable difference in the leve
l of V-ATPase mRNA between normal and pancreatic carcinoma tissues, wi
th no evident difference in the expression of the beta-actin gene. Imm
unohistochemically, 42 out of 46 invasive ductal cancers (92%) display
ed a mild to marked immunoreactivity for V-ATPase in the cytoplasm, wh
ereas neither non-invasive ductal cancers nor benign cystic neoplasms
expressed detectable immunoreactive proteins. These findings suggest t
hat the overexpression of V-ATPase protein is characteristic of invasi
ve pancreatic tumours. V-ATPase may play some crucial roles in tumour
progression.