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Preprotachykinin mRNA in human carcinoid tumours
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PREPROTACHYKININ mRNA IN HUMAN CARCINOID TUMOURS
N.CORBALLyI,K.TIPTON 2 and D.POWELL 1 , iEndocrine Department,Mater Hospital, Eccles Street,Dublin 7 and 2Biochemistry Department, Trinity Colleqe,Dublin University,Dublin. The chemically related tachykinin peptides include substance P(SP), substance K (SK, tachykininA) and neuropeptide K(NPK), recently identified in mammalian tissue. Human carcinoid tt~ours derived from the enterochrcmaffin cells in the gastrointestinal tract contain and secrete large amounts of tachvkinin-like i~nunoreactive peptides including SP, SK and NPK. These tachykinins are produced by a single preprotachykinin (PPT) gene, which through alternative snlicing events gives rise to three (~,~,~)PPTmRNAs. The ~PPT contains not only SP but also SK and NPK. In this study the presence of @PPTmRNA in a number of carcinoid tt~nours was examined using a ~PPTcDNAprobe (gift of T.Bonner,NIH,USA). Total cellular RNA, extracted from freshly frozen carcinoid tumours was shown to be intact by its ability to direct protein synthesis in a cell-free translation system. The RNA was separated on a de~gturing gel by electrophoresis and examined by Northern blot analysis with a--P-labelled, nick-translated @PPTcDNA probe. The presence of SP-like ~ o r e a c t i v i t y ( S P - L I ) in the carcinoid tumours was also determined by radioin~unoassay. Seven of eight carcinoid samples showed SP-LI. Six of these samples gave a positive signal for #PPTmRNA. One sample with no SP-LI had no~PPTmRNA and a bladder tumour sar~le (as a negative control) had no ~PPTmRNA. One SP-LI tumour had no ~PVIhLRNA. This tt~nourmay contain ~PPTmRNA,(not conpletely homologous to @ P ~ , hence the probe may have been removed by the high stringency washes) which nroduces only SP. Supported by the Health Research Board of Ireland.
MULTI-HORMONE PRODUCING APUDOMAS ARE BEST RESPONDERS [0 STREPTOZOTOCIN K.D. B~CH~NAN I, M,M.T. O'HARE I, C.J.F. RUSSELL 2, T.L. K~NNEDY 2 and D.R. ~ADDEN , Department of Medicine, Queen's U n i v e r s i t y , Surgical and Metabolic Units, Royal V i c t o r i a H o s p i t a l , B e l f a s t , BT12 6BJ, N. I r e l a n d . S t r e p t o z o t o c i n is an e f f e c t i v e treatment f o r m e t a s t a t i c APUDomas. However the response is v a r i a b l e , and resistance to the drug, are encountered. The reasons f o r these phenomena are i l l understood. Fifteen p a t i e n t s with a t o t a l of 19 APUDomas, who had inoperable disease and whose l i f e s t y l e s were severely affected because of tumour growth or endocrine syndrome were treated with S t r e p t o z o t o c i n duringmthe years 1969 to 1986. The drug in most instances was given alone (0.5 g/mm as an intravenous bolus d a i l y f o r 5 days), but in 3 instances was given i n t r a - a r t e r i a l l y and in another 3 combined with other c y t o t o x i c drugs (5 Fluorouracil or Adriamycin). Eleven out of 19 APUDomas had remissions with reduction in tumour size and a m e l i o r a t i o n of the endocrine syndrome, remissions l a s t i n g I-2 years. All VIPomas responded, as did the m a j o r i t y of insulinomas and gastrinomas but poor responses were noted in undetermined types, carcinoids and a neurotensinoma. When c i r c u l a t i n g and tissue pancreatic polypeptide (PP) levels were examined, best responses were apparent in those p a t i e n t s with elevated PP l e v e l s . However good responses appeared more r e l a t e d to the number of hormones found in the tumour or c i r c u l a t i o n , good responses being more common in p a t i e n t s secreting 2 or more hormones, than in p a t i e n t s secreting ] or more. In conclusion multi-hormone producing APUDomas are more susceptible to Streptozotocin than s i n g l e hormone or non-secretory types.
PREPROTACHYKININ mRNA IN HUMAN CARCINOID TUMOURS
N.CORBALLyI,K.TIPTON 2 and D.POWELL 1 , iEndocrine Department,Mater Hospital, Eccles Street,Dublin 7 and 2Biochemistry Department, Trinity Colleqe,Dublin University,Dublin. The chemically related tachykinin peptides include substance P(SP), substance K (SK, tachykininA) and neuropeptide K(NPK), recently identified in mammalian tissue. Human carcinoid tt~ours derived from the enterochrcmaffin cells in the gastrointestinal tract contain and secrete large amounts of tachvkinin-like i~nunoreactive peptides including SP, SK and NPK. These tachykinins are produced by a single preprotachykinin (PPT) gene, which through alternative snlicing events gives rise to three (~,~,~)PPTmRNAs. The ~PPT contains not only SP but also SK and NPK. In this study the presence of @PPTmRNA in a number of carcinoid tt~nours was examined using a ~PPTcDNAprobe (gift of T.Bonner,NIH,USA). Total cellular RNA, extracted from freshly frozen carcinoid tumours was shown to be intact by its ability to direct protein synthesis in a cell-free translation system. The RNA was separated on a de~gturing gel by electrophoresis and examined by Northern blot analysis with a--P-labelled, nick-translated @PPTcDNA probe. The presence of SP-like ~ o r e a c t i v i t y ( S P - L I ) in the carcinoid tumours was also determined by radioin~unoassay. Seven of eight carcinoid samples showed SP-LI. Six of these samples gave a positive signal for #PPTmRNA. One sample with no SP-LI had no~PPTmRNA and a bladder tumour sar~le (as a negative control) had no ~PPTmRNA. One SP-LI tumour had no ~PVIhLRNA. This tt~nourmay contain ~PPTmRNA,(not conpletely homologous to @ P ~ , hence the probe may have been removed by the high stringency washes) which nroduces only SP. Supported by the Health Research Board of Ireland.
MULTI-HORMONE PRODUCING APUDOMAS ARE BEST RESPONDERS [0 STREPTOZOTOCIN K.D. B~CH~NAN I, M,M.T. O'HARE I, C.J.F. RUSSELL 2, T.L. K~NNEDY 2 and D.R. ~ADDEN , Department of Medicine, Queen's U n i v e r s i t y , Surgical and Metabolic Units, Royal V i c t o r i a H o s p i t a l , B e l f a s t , BT12 6BJ, N. I r e l a n d . S t r e p t o z o t o c i n is an e f f e c t i v e treatment f o r m e t a s t a t i c APUDomas. However the response is v a r i a b l e , and resistance to the drug, are encountered. The reasons f o r these phenomena are i l l understood. Fifteen p a t i e n t s with a t o t a l of 19 APUDomas, who had inoperable disease and whose l i f e s t y l e s were severely affected because of tumour growth or endocrine syndrome were treated with S t r e p t o z o t o c i n duringmthe years 1969 to 1986. The drug in most instances was given alone (0.5 g/mm as an intravenous bolus d a i l y f o r 5 days), but in 3 instances was given i n t r a - a r t e r i a l l y and in another 3 combined with other c y t o t o x i c drugs (5 Fluorouracil or Adriamycin). Eleven out of 19 APUDomas had remissions with reduction in tumour size and a m e l i o r a t i o n of the endocrine syndrome, remissions l a s t i n g I-2 years. All VIPomas responded, as did the m a j o r i t y of insulinomas and gastrinomas but poor responses were noted in undetermined types, carcinoids and a neurotensinoma. When c i r c u l a t i n g and tissue pancreatic polypeptide (PP) levels were examined, best responses were apparent in those p a t i e n t s with elevated PP l e v e l s . However good responses appeared more r e l a t e d to the number of hormones found in the tumour or c i r c u l a t i o n , good responses being more common in p a t i e n t s secreting 2 or more hormones, than in p a t i e n t s secreting ] or more. In conclusion multi-hormone producing APUDomas are more susceptible to Streptozotocin than s i n g l e hormone or non-secretory types.