Point mutation in activated c-Ha-ras gene of a chemically induced transplantable human pancreas carcinoma

The authors have reported a model of human pancreas carcinogenesis where repeated treatment with MNU of explants results in the development of transplantable carcinoma. This report compares the endonuclease digests of DNAs from normal human pancreas (HP) and MNU-induced transplantable tumor (HP-T1) analyzed with /sup 32/P-labelled Ha-ras probe prepared from clone BS-9. The hybridization patterns of BamHI, BglII, EcoRI and HindIII digests of HP were significantly different from those of HP-T1. In EcoRI digests a 3.0 kb fragments of HP-T1 DNA hybridized with Ha-ras probe instead of a 4.3 kb fragments seen in HP DNA. The pattern for HindIII digests was similar to those of EcoRI. The BgIII digests of HP DNA revealed two hybridizing fragments of 8.0 and 4.3 kb whereas those of HP-T1 DNA fragments measured 8.5 and 4.0 kb. BamHI treated HP DNA showed only hybridizing fragments of 6.6 kb while the HP-T1 DNA showed to hybridizing fragments of 6.8 and 7.2 kb. The digested DNAs by HhaI, HinfI, KpnI, pstI, PvuII, SaII, SstI, TaqI and XbaI showed similar hybridization profiles. The point mutation in c-Ha-ras was examined in the HpaII and MspI double digests of both DNAs by 0.6 Kb SmaI fragments of pEJ. The hybridizedmore » fragments measured 412 and 355 bp in DNA digests from tumor and normal pancreas respectively.« less