Farah Zia

Prostaglandin E2 and vasoactive intestinal peptide increase vascular endothelial cell growth factor mRNAs in lung cancer cells.

The effects of prostaglandin E2 (PGE2) and vasoactive intestinal peptide (VIP) on vascular endothelial cell growth factor (VEGF) mRNAs were investigated using lung cancer cells. By RT-PCR, VEGF(121), VEGF(165), and VEGF(189), but not VEGF(206) isoforms were detected in all lung cancer cell lines and biopsy specimens examined. By Northern blot, VEGF mRNA was detected in all small cell lung cancer (SCLC) and non-SCLC (NSCLC) cell lines examined. PGE2, VIP and forskolin caused increased VEGF expression in a time- and concentration-dependent manner using NSCLC cell line NCI-H157. Approximately 1 microM PGE2, 0.1 microM VIP and 50 microM forskolin caused cAMP elevation, 64-, 33- and 128-fold, respectively, using NCI-H157 cells after 5 min. The increase in cAMP caused by PGE(2) and VIP was reversed by somatostatin (SST). Also 1 microM PGE2, 0.1 microM VIP and 50 microM forskolin increased the VEGF mRNA 2.0-, 1.5- and 2.3-fold, respectively, after 4 h. The increase in VEGF mRNA caused by PGE2, VIP and forskolin was inhibited by H-89, a protein kinase A inhibitor. A VIP receptor antagonist, VIPhybrid, inhibited the increase in cAMP and VEGF mRNA caused by VIP. By ELISA, VEGF was detected in the conditioned media exposed to the lung cancer cell lines. These results suggest that VEGF synthesis in and secretion from lung cancer cells can be regulated by agents, which cause adenylyl cyclase activation.

Pituitary adenylate cyclase activating polypeptide receptors are present on small cell lung cancer cells

The effect of pituitary adenylate cyclase activating polypeptide (PACAP) on small cell lung cancer (SCLC) cells was investigated. In Fura 2-AM loaded NCI-N417 cells, PACAP-27 or PACAP-38 elevated cytosolic calcium in a dose-dependent manner. The cytosolic calcium was elevated from 133 to 185 nM with PACAP-27 (100 nM). Because PACAP-27 strongly elevated cytosolic calcium after the addition of 1 mM EGTA, PACAP released calcium from intracellular pools using NCI-N417 cells; similar results were obtained for SCLC cell line NCI-H345. Pituitary adenylate cyclase activating polypeptide-27 inhibited 125I-VIP and 125I-PACAP binding to NCI-N417 cells with high affinity (IC50 = 30 and 5 nM), whereas VIP inhibited 125I-VIP and 125I-PACAP-27 binding with IC50 values of 5 and 200 nM. Both 100 nM VIP and PACAP-27 elevated cAMP levels in NCI-H345 cells. In contrast, 1 microM VIP had no effect on cytosolic calcium, whereas 100 nM PACAP-27 caused a strong calcium response. Both 100 nM VIP and 10 nM PACAP-27 significantly stimulated the clonal growth of NCI-H345 cells. These data suggest that biologically active VIP and PACAP receptors are present on SCLC cells.

BW2258U89 : A GRP RECEPTOR ANTAGONIST WHICH INHIBITS SMALL CELL LUNG CANCER GROWTH

The ability of reduced peptide bond analogues of gastrin releasing peptide (GRP) to antagonize small cell lung cancer (SCLC) GRP receptors was investigated. BW462U89, BW1023U90, BW2123U89 and BW2258U89 inhibited binding of (125I-Tyr4) BN to NCI-H345 cells with IC50 values of 5, 6, 140 and 10 nM respectively. The GRP analogues had no effect on basal cytosolic Ca2+ but inhibited the increase caused by 10 nM BN. BW462U89 reversibly blocked the increase in cytosolic Ca2+ caused by BN. The GRP analogues (1 microM) inhibited NCI-H345 colony formation in the absence or presence of 10 nM BN. Also, BW2258U89 (0.4 mg/kg, s.c. daily) inhibited xenograft growth in nude mice. These data indicate that BW2258U89 inhibits SCLC growth in vitro and in vivo.

PACAP stimulates c-fos mRNAs in small cell lung cancer cells.

The effects of PACAP on c-fos mRNA using small cell lung cancer (SCLC) cell was investigated. PACAP-27 (100 nM) increased c-fos mRNA 5-fold using NCI-N417 cells. The increase was concentration dependent with 0.1 nM PACAP-27 half maximally increasing c-fos mRNA. Also the increase in c-fos mRNA caused by PACAP was time dependent; being maximal after 1 hour and returning to basal values after 4 hours. PACAP-38 but not PACAP(28-38) increased c-fos mRNA. One uM PACAP(6-38), a PACAP receptor antagonist, inhibited the increase in c-fos mRNA caused by 1 nM PACAP. These data indicate that PACAP stimulates nuclear oncogene expression in SCLC cells.

Thymosinα1 is chemopreventive for lung adenoma formation in A/J mice

Abstract The effects of thymosin (THN) α1 were investigated using the urethane injection carcinogenesis A/J mouse model. Lung adenomas were observed 2.5, 3, and 4 months after urethane injection (400 mg/kg i.p.) into female A/J mice. Daily administration of THNα1 (0.4 mg/kg, s.c.) reduced lung adenoma multiplicity significantly, by approximately 45, 40, and 17%, respectively, 2.5, 3, and 4 months after urethane injection. Animals treated with THNα1 had a significantly greater white cell density than control A/J mice. Endogenous THNα1-like peptides were detected in the mouse lung. By radioimmunoassay and by Western blot, prothymosin α was detected in the mouse lung. By immunocytochemistry, THNα1-like peptides were detected in all lung compartments including the bronchus, adenoma, bronchioles, and alveoli. These results indicate that exogenous THNα1 prevents lung carcinogenesis in A/J mice.

Neuromedin B stimulates arachidonic acid release, c-fos gene expression, and the growth of C6 glioma cells

The effects of neuromedin B (NMB) on C6 glioma cells were investigated. NMB bound with high affinity (IC50 = 1 nM) to C6 cells whereas BN and GRP were less potent (IC50 = 40 and 100 nM). NMB (1 nM) elevated cytosolic Ca2+ in individual C6 cells and the increase in cytosolic Ca2+ was reversed by 1 microM [D-Arg1, D-Pro2,D-Trp7.9,Leu11]substance P [APTTL]SP, a broad spectrum antagonist. NMB stimulated [3H]arachidonic acid release from C6 cells and the increase in [3H]arachidonic acid release was reversed [APTTL]SP. NMB increased transiently c-fos gene expression in C6 cells. NMB increased the number of C6 colonies in soft agar and the increase in growth caused by NMB was reversed by [APTTL]SP. These data suggest that NMB receptors may regulate the proliferation of C6 cells.

Corticotropin-releasing factor stimulates cyclic AMP, arachidonic acid release, and growth of lung cancer cells

The effects of corticotropin-releasing factor (CRF) on human lung cancer cell lines was investigated. Corticotropin-releasing factor increased the cAMP levels in a dose-dependent manner; CRF (100 nM) elevated the cAMP levels approximately eleven-fold using NCI-H345 cells and increased the gastrin-releasing peptide (GRP) secretion rate by approximately 70%. Similarly, sauvagine, a structural analogue of CRF, elevated the cAMP levels with a half-maximal effective dose (ED50) of 20 nM. The increase in cAMP caused by CRF and sauvagine was reversed by alpha-helical CRF(9-41). Corticotropin-releasing factor had no effect on cytosolic calcium but stimulated [3H]arachidonic acid release from NCI-H1299 cells with an ED50 of 30 nM. The increase in [3H]arachidonic acid release caused by 100 nM CRF was significantly reversed by 1 or 10 microM alpha-helical CRF(9-41). Also, CRF stimulated the clonal growth of NCI-H345 and H720 cells and the growth increase caused by CRF was reversed by alpha-helical CRF(9-41). These data suggest that CRF may be a regulatory peptide in lung cancer.