Small cell lung carcinoma (SCLC) ()displays neuroendocrine features exemplified by the presence of cytoplasmic neurosecretory granules containing a wide variety of mitogenic neuropeptides including gastrin-releasing peptide, arginine vasopressin, neurotensin, cholecystokinin, and many others(1, 2) . Significantly, SCLC also expresses receptors for these neuropeptides, thereby establishing autocrine-stimulated cell growth(3) . The number and variability of neuropeptides released from individual small cell carcinomas hampers effective blockade of mitogenic signaling at the level of ligand/receptor binding using specific neuropeptide antagonists. This redundancy at the level of receptor signaling highlights the importance of defining the intracellular components involved in mitogenic signal transduction in SCLC where convergence of multiple neuropeptide receptor systems into common pathways would be anticipated.

Molecular cloning of the receptors for gastrin-releasing peptide, vasopressin, and gastrin/cholecystokinin reveals that they are members of the superfamily of seven membrane-spanning receptors(4, 5, 6, 7, 8) . As a class, these receptors initiate signaling in response to ligand binding by interacting with heterotrimeric G proteins. Although the repertoire of G proteins potentially involved in neuropeptide signaling in SCLC is quite large, the failure of pertussis toxin to appreciably inhibit in vitro growth of SCLC (9) suggests that the pertussis toxin-sensitive G and G proteins are unlikely to be dominant components of mitogenic signaling in SCLC. In fact, the prominence of phospholipase C activation and Ca mobilization (10, 11, 12) by neuropeptides in SCLC points to the pertussis toxin-insensitive G proteins as likely candidates for mediating autocrine signaling in SCLC because the G family of G proteins are known to stimulate several of the phospholipase C isoforms(13, 14) .

To examine the role of G proteins in SCLC growth pathways, we have used retrovirus-mediated gene transfer to express a GTPase-deficient, constitutively active form of the family member, G, in SCLC lines. We find that expression of GTPase-deficient G in SCLC markedly inhibits their growth and oppositely affected two signal transduction pathways normally engaged by neuropeptides and muscarinic agonists in SCLC; Ca mobilization was inhibited, and the c-Jun NH-terminal kinase/stress-activated protein kinase pathway was constitutively activated. The data indicate that derangement of coordinated neuropeptide signaling in SCLC leads to strong inhibition of growth.

MATERIALS AND METHODS

Retrovirus-mediated Gene Transfer and Cell Culture

Immunoblot Analysis of Q212L Expression

Determination of Soft Agar Cloning Efficiency

Analysis of Total Inositol Phosphates

Determination of Intracellular CaLevels

Assay of MAP Kinase and c-Jun NH-terminal Kinase Activities

The activity of c-Jun NH-terminal kinases was determined essentially as described(21) . SCLC cells were collected by centrifugation (5 min, 1000 g) and lysed (4 °C, 30 min) in 0.5 ml of 25 mM HEPES (pH 7.7), 20 mM -glycerophosphate, 0.1 mM sodium vanadate, 0.1% Triton X-100, 0.3 M NaCl, 1.5 mM MgCl, 0.2 mM EDTA, 0.5 mM dithiothreitol, 2 µg/ml leupeptin, and 4 µg/ml aprotinin. Following a 5-min microcentrifugation (10,000 g), aliquots of the soluble extracts containing 400 µg of protein were incubated for 2 h at 4 °C with GST-c-Jun(1-79) adsorbed to glutathione-agarose as described(21) . The GST-c-Jun(1-79) beads were washed four times by repetitive centrifugation in 20 mM HEPES (pH 7.7), 50 mM NaCl, 2.5 mM MgCl, 0.1 mM EDTA, and 0.05% Triton X-100 and then incubated for 20 min at 30 °C in 40 µl of 50 mM -glycerophosphate (pH 7.6), 0.1 mM sodium vanadate, 10 mM MgCl, and 20 µM [-P]ATP (25,000 cpm/pmol). The reactions were terminated with 10 µl of SDS-polyacrylamide gel electrophoresis sample buffer, boiled, and submitted to 10% SDS-polyacrylamide gel electrophoresis. The GST-c-Jun(1-79) polypeptides were identified in Coomassie-stained gels, excised, and counted in a scintillation counter.

RESULTS AND DISCUSSION

To test the role of G family members in SCLC growth, we analyzed the effects of expression of GTPase-deficient forms of family members on neuropeptide-stimulated signaling and growth in SCLC lines. We have previously used retrovirus-mediated gene transfer as a standard method to express exogenous gene products in many different cell lines(17, 20) . However, repeated attempts to establish a stable PA317 retroviral packaging line expressing the GTPase-deficient form of (Q209L) failed, suggesting that the Q209L polypeptide was cytotoxic in these lines and did not permit retroviral packaging. Subsequent attempts with the GTPase-deficient form of the family member, Q212L, were successful such that a stable PA317 retroviral packaging line that secreted virus encoding the Q212L polypeptide was established.

Retrovirus encoding the Q212L polypeptide as well as the vector, LNCX, lacking a cDNA insert were used to infect four SCLC lines (H69, H345, N417, and H1048) as well as two NSCLC cell lines (H157 and H2122). Stable populations of tumor cells were selected for resistance to G418. Immunoblotting with an -specific antibody verified that an polypeptide was indeed expressed in the Q212L-transfected lines (Fig. 1A) relative to the LNCX-transfected controls. The lung cancer cell lines lack detectable endogenous because it is normally restricted in expression to cells of hematopoetic origin(22) . As predicted for an family member, expression of the Q212L polypeptide in the SCLC and NSCLC lines persistently stimulated phospholipase C activity as shown by the 2-4-fold increase in total inositol phosphate content observed in the Q212L-expressing cells relative to the LNCX-transfected lines (Fig. 1B). Expression of the Q212L polypeptide in the H1048 line, a small cell carcinoma of extrapulmonary origin(23) , stimulated basal phospholipase C activity at least 10-fold. Repeated attempts to stably express Q212L in another extrapulmonary small cell line (H510) failed, suggesting that small cell carcinomas of extrapulmonary origin may be particularly sensitive to Q212L. Thus, the data show that Q212L was functionally expressed in SCLC and NSCLC lines and constitutively activated phospholipase C activity.

Figure 1: Functional expression of GQ212L in lung cancer cell lines. A, immunoblot analysis of Q212L expression in SCLC and NSCLC lines. Extracts from the indicated lung cancer cell lines were resolved by 10% SDS-polyacrylamide gel electrophoresis, transferred electrophoretically to nitrocellulose, and immunoblotted with a rabbit polyclonal anti- antiserum. B, basal phospholipase C (PLC) activation in lung cancer cell lines expressing Q212L. The indicated cell lines were labeled for 16-24 h with [H]inositol, and the accumulation of total inositol phosphates was determined as described under ``Materials and Methods.'' The data are presented as the means ± S.E. of three independent experiments, except for H69, which depicts the average of two experiments.

Colony formation in semi-solid medium was used to monitor the transformed phenotype of SCLC and NSCLC expressing Q212L. The ability of the Q212L-expressing SCLC to form colonies in soft agar was inhibited approximately 70% respective to lines infected with the vector containing no cDNA insert (Fig. 2). In contrast, Q212L expression did not influence the growth of two NSCLC lines (H157 and H2122). Note that the absolute cloning efficiency of the different lung cancer cell lines varied considerably, although the percentage of inhibition of soft agar cloning efficiency by Q212L was similar. The soft agar cloning efficiencies of H345 cells expressing GTPase-deficient forms of and were 96 and 139%, respectively, of the cloning efficiency of H345 cells infected with LNCX (data not shown), indicating that inhibition of SCLC growth is specific for the family members. This finding is consistent with the inability of pertussis toxin to significantly stimulate or inhibit the in vitro growth of SCLC lines(9) . As a more stringent indicator of the transformed growth properties of SCLC lines expressing Q212L, the H1048 lines infected with LNCX or Q212L were implanted in the flanks of nude mice. Of the three mice injected with H1048-LNCX cells (10 cells per mouse), all formed large tumors after 6-8 weeks. In contrast, none of the three mice injected with H1048-Q212L cells developed tumors within 8 weeks. Thus, expression of Q212L in SCLC but not NSCLC significantly inhibited their in vitro and in vivo growth properties.

Figure 2: Soft agar cloning efficiencies of control and Q212L-expressing lung cancer cell lines. Single cell suspensions of the indicated cell lines were prepared and cultured in growth medium containing 0.3% agar nobel as described under ``Materials and Methods.'' The data are presented as cloning efficiencies (percent of seeded cells that formed a colony) and are the means of two independent experiments where each experiment was assessed in triplicate.

To define the mechanism by which Q212L inhibits SCLC growth, the influence of Q212L expression on neuropeptide signaling was examined. A prominent indicator of neuropeptide signaling in SCLC is intracellular Ca mobilization(10, 11, 12) , which can be readily detected by changes in fluorescence of the Ca-sensitive dye, Indo-1. The H1048 and H345 SCLC lines infected with the LNCX vector alone show marked Ca responses following exposure to exogenous cholecystokinin (Fig. 3A) and the muscarinic agonist, carbachol (Fig. 3C), respectively. The H1048-LNCX cells also exhibit a measurable Ca mobilization response to bradykinin (Fig. 3B). The H1048 and H345 SCLC lines expressing Q212L exhibited markedly blunted Ca mobilization responses following application of cholecystokinin, bradykinin, and carbachol. The data are consistent with a mechanism whereby Q212L expression desensitizes hormone and neuropeptide-regulated Ca mobilization in a heterologous fashion. Previously, workers have shown that chronic activation of phospholipase C systems induces desensitization or down-regulation of the the inositol trisphosphate-gated Ca channel in the endoplasmic reticulum (24) as well as induction of polyphosphatidyinositol phosphatases. ()

Figure 3: Influence of GQ212L on the regulation of intracellular Ca levels by neuropeptides and hormones in SCLC lines. LNCX and Q212L-expressing H345 and H1048 cells in HITES medium were loaded with the calcium indicator Indo-1 AM, and the changes in intracellular Ca levels were determined as described under ``Materials and Methods.'' The data are representative of three independent experiments with the indicated cell lines.

Besides a blunted growth rate, SCLC H345 cells expressing Q212L are significantly increased in cell size relative to LNCX-infected controls. In addition, both H345 and H1048 exhibited increased adherence to tissue culture plastic upon expression of Q212L. Thus, expression of Q212L alters the morphologic properties of some of the SCLC lines. Interestingly, a rat neuroendocrine tumor cell line, PC12 pheochromocytoma cells, undergoes marked growth arrest and neuronal differentiation upon introduction of Q212L by retrovirus-mediated gene transfer. ()The inhibition of SCLC growth observed with Q212L expression is likely to be related, at least in part, to loss of Ca signaling, indicating that the Ca mobilization is a major mitogenic signal in SCLC. However, it seemed possible that additional signal pathways involved in regulation of growth and differentiation were being regulated in response to expression of Q212L, especially in relation to altered cellular morphology. The activity of the p42/44 MAP kinases was assessed because they have been previously shown to be persistently stimulated in morphologically differentiated PC12 cells(20) . Extracts from LNCX and Q212L-expressing H345 cells were fractionated on MonoQ fast protein liquid chromatography and analyzed for MAP kinase activity with an EGFR peptide phosphorylation assay. The data in Fig. 4reveal that increased p42/44 MAP kinase activity relative to control cell extracts was not observed in fractionated extracts from Q212L-expressing H345 cells. In addition, incubation of the various SCLC lines with neuropeptides including bombesin and vasopressin failed to significantly stimulate p42/44 MAP kinase activity (data not shown), although treatment of H345 cells with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate markedly increased MAP kinase activity (Fig. 4).

Figure 4: MonoQ fast protein liquid chromatography analysis of p42/44 MAP kinase activity in H345 cells expressing GQ212L. Extracts of H345 cells expressing Q212L or the empty LNCX vector were fractionated on MonoQ fast protein liquid chromatography. Fractions were collected and assayed for MAP kinase activity with EGFR peptide. The results are from one experiment that is representative of two other independent experiments.

The recently defined c-Jun NH-terminal kinases or stress-activated protein kinases are members of the MAP kinase family that exhibit homology to the p42/44 MAP kinases (26, 27) and are strongly activated by exposure to heat shock and ultraviolet light (21) . Analysis of c-Jun NH-terminal kinase activity using an immobilized GST-c-Jun(1-79) assay revealed a statistically significant 1.8-fold increase in c-Jun NH-terminal kinase/stress-activated protein kinase activity in extracts from H345 cells expressing Q212L relative to control cells (Fig. 5A). The magnitude of c-Jun NH-terminal kinase activation by Q212L is similar to the level of activation observed in response to acute treatment of H345 cells with a neuropeptide, bombesin, or a muscarinic agonist, carbachol (Fig. 5B). Furthermore, c-Jun NH-terminal kinase activity is strongly stimulated (10-fold) by exposure of H345 cells to ultraviolet irradiation (UV-C, 96 J/M), but not by strong activation of protein kinase C with 12-O-tetradecanoylphorbol-13-acetate (Fig. 5C) that leads to marked p42/44 MAP kinase activation (Fig. 4). Thus, the findings demonstrate a significant activation of protein kinases characteristic of the c-Jun NH-terminal kinases/stress-activated protein kinases but not the p42/44 MAP kinases following expression of Q212L in a SCLC line.

Figure 5: Regulation of c-Jun amino-terminal kinase activity in H345 cells by GQ212L, hormones, and ultraviolet light. A, H345 cells expressing the LNCX vector or Q212L were incubated for 10 min at 37 °C and soluble extracts were prepared and assayed for c-Jun NH-terminal kinase activity as described under ``Material and Methods.'' B, H345 cells were incubated at 37 °C for 15 min in the presence or the absence of 100 nM bombesin or 10 µM carbachol. The cells were collected by centrifugation, lysed, and assayed for c-Jun NH-terminal kinase activity as in A. C, H345-LNCX cells were UV irradiated (192 J/M), incubated for 30 min at 37 °C or incubated for 10 min with 100 nM 12-O-tetradecanoylphorbol-13-acetate, and assayed for c-Jun NH-terminal kinase activity as described above. The data are the mean of five, three, and three independent experiments for A, B, and C, respectively. * indicates p < 0.05.

Elevated cAMP and activation of cAMP-dependent protein kinase are growth inhibitory in many cell systems. It has been previously established that expression of Q212L in Swiss 3T3 fibroblasts significantly stimulates cAMP-dependent protein kinase through a protein kinase C-dependent mechanism(17) , a finding that may be partially responsible for the growth inhibition observed in Swiss 3T3 cells. However, the basal activity of cAMP-dependent protein kinase in Q212L-expressing H345 and H69 cells was 85 and 117% of LNCX-expressing H345 and H69 cells, respectively, indicating that the cAMP-dependent protein kinase pathway is not involved in the Q212L-induced growth inhibition observed in SCLC lines.

The results show that cellular expression of Q212L inhibits the growth of SCLC but not NSCLC. The selective inhibition of SCLC growth relative to NSCLC growth is likely to be explained by the different cellular pathways that exert dominance in growth regulation in the two lung cancer cell types. Oncogenic activation of Ras is frequently observed in NSCLC. In fact, H157, a squamous cell carcinoma, and H2122, an adenocarcinoma, have been previously shown to express mutated forms of Ki-Ras(28) . In addition, NSCLC frequently overexpress specific receptor tyrosine kinase systems such as the epidermal growth factor receptor(29) . In contrast, SCLC is characterized by the notable absence of GTPase-deficient forms of Ras, and overexpression of epidermal growth factor receptors is rare(28, 29) . Instead, neuropeptide autocrine loops utilizing seven membrane-spanning receptors and heterotrimeric G proteins are proposed to be the primary mitogenic inputs in SCLC. Previous findings that Q209L expression in NIH 3T3 fibroblasts leads to cellular transformation (30, 31) is consistent with a role for G proteins, phospholipase C, and Ca mobilization in mitogenic signaling. However, other studies revealed that Q212L expression in Swiss 3T3 fibroblasts profoundly inhibited bombesin (gastrin-releasing peptide) signal transduction including calcium mobilization, MAP kinase activation, and arachidonic acid release. The net effect was a nearly complete inhibition of bombesin (gastrin-releasing peptide)-stimulated DNA synthesis(17) . Similar to the latter studies, our findings show that expression of Q212L in SCLC lines resulted in strong inhibition of neuropeptide-regulated Ca mobilization (Fig. 3) and dramatically reduced the ability of the cells to growth in soft agar (Fig. 2). These conflicting results concerning cellular actions of GTPase-deficient G proteins may reflect different levels of expression of the -subunits in the various cell lines where low expression results in transformation and high expression leads to negative modulation of intracellular signaling pathways and growth arrest. Alternatively, the ability of G, phospholipase C, and Ca mobilization to stimulate DNA synthesis may be quite variable among different cell types.

Expression of GTPase-deficient Q212L oppositely affected two signal transduction pathways normally engaged by neuropeptides and muscarinic agonists in SCLC; Ca mobilization was inhibited, and the c-Jun NH-terminal kinase/stress-activated protein kinase pathway was constitutively activated. Thus, Q212L expression induced discordant signaling in SCLC. We have found that Q212L expression also constitutively activates the c-Jun NH-terminal kinase/stress-activated protein kinase pathway in PC12 cells where growth arrest and neuronal differentiation is observed. The failure of phorbol esters to significantly activate the c-Jun NH-terminal kinase/stress-activated protein kinase pathway (Fig. 5C) in SCLC indicates that the phorbol ester-regulated forms of protein kinase C are not likely to mediate the activation of the c-Jun NH-terminal kinase/stress-activated protein kinase pathway, although the potential involvement of nonphorbol ester-sensitive protein kinase C isoforms cannot be eliminated. Constitutive activation of the c-Jun NH-terminal kinase/stress-activated protein kinase pathway in the absence of Ca mobilization and p42/44 MAP kinase activation is correlated with a strong growth arrest in two cell types, SCLC and PC12 cells. It will be of interest to observe the spectrum of tumor cells where this response is growth inhibitory.

Ultraviolet irradiation of H345 cells strongly activates the c-Jun NH-terminal kinase/stress-activated protein kinase pathway (Fig. 5C) and leads to a rapid apoptotic-like cell death. ()The 2-fold activation of the c-Jun NH-terminal kinase/stress-activated protein kinase pathway with Q212L expression relative to the greater than 10-fold activation by UV irradiation may, in addition to inhibited Ca mobilization, explain the strong growth arrest observed in the SCLC lines. We hypothesize that high level constitutive activation of the c-Jun NH-terminal kinase/stress-activated protein kinase pathway in the absence of neuropeptide-stimulated Ca mobilization may have lethal consequences in SCLC. Consistent with this possibility was our inability to isolate Q212L-expressing clones in some SCLC lines such as H510, despite repeated attempts. We have found that a proximal regulator of c-Jun NH-terminal kinases is a MEK kinase distinct from Raf(25, 32) . MEK kinase activation is Ras-regulated and independent of Raf(32) . Expression of activated MEK kinase-1 leads to cell death in several fibroblast systems and differentiation of PC12 cells ()similar to the phenotype observed with activated members such as Q212L. Thus, the MEK kinase/c-Jun NH-terminal kinase regulatory pathways may contribute to growth inhibition and possibly cell death, a sharply contrasting phenotype from that observed with activated Raf expression.

These findings indicate that it is possible to inhibit cell growth of selected tumor cell types by selectively disrupting coordinated signal transduction pathways. Increasing awareness that signals controlling growth and apoptosis are overlapping is insightful in regards to these results. We suggest that the balance and magnitude of specific signal transduction pathways regulated by hormones and growth factors can determine commitment to tumor cell growth or arrest. Identifying tumors that have a strong growth inhibitory response resulting from activated expression will allow a new pharmacologic and genetic approach to cancer therapeutics. The ability of G family members of G proteins to regulate the c-Jun NH-terminal kinase/stress-activated protein kinase pathway and to cause growth inhibition in SCLC and some fibroblasts focuses our attention on the effectors capable of inhibiting tumor cell growth.

FOOTNOTES

*

This work was supported by National Institutes of Health Grants CA 58157, CA 46934, DK 19928, and GM 48826. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked ``advertisement'' in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

§

To whom correspondence should be addressed: Division of Renal Medicine, C-281, University of Colorado Health Sciences Center, 4200 E. Ninth Ave., Denver, CO 80262. Tel.: 303-270-6065; Fax: 303-270-4852; heasley_l@defiance.UCHSC.edu.

()

The abbreviations used are: SCLC, small cell lung carcinoma; MAP, mitogen-activated protein; MEK, MAPK/ERK kinase; NSCLC, nonsmall cell lung carcinoma.

()

Lobaugh, L. A., Eisfelder, B., Johnson, G. L., and Putney, J. W., Jr., submitted for publication.

()

L. E. Heasley, B. Storey, and J. Zamarripa, unpublished results.

()

B. Storey and L. E. Heasley, unpublished results.

()

C. A. Lange-Carter and G. L. Johnson, unpublished results.

REFERENCES

1. Sorenson, G. D., Pettengill, O. S., Brinck-Johnsen, T., Cate, C. C., and Maurer, L. H. (1981) Cancer (Phila.) 47, 1289-1296
2. Bunn, P. A., Jr., Dienhart, D. G., Chan, D. C., Puck, T. T., Tagawa, M., Jewett, P. B., and Braunschweiger, E. (1990) Proc. Natl. Acad. Sci. U. S. A. 87, 2162-2166 [Abstract/Free Full Text]
3. Cuttitta, F., Carney, D. N., Mulshine, J., Moody, T. W., Fedorko, J., Fischler, A., and Minna, J. D. (1985) Nature 316, 823-826 [CrossRef][Medline] [Order article via Infotrieve]
4. Battey, J. F., Way, J. M., Corjay, M. H., Shapira, H., Kusano, K., Harkins, R., Wu, J. M., Stattery, T., Mann, E., and Feldman, R. I. (1991) Proc. Natl. Acad. Sci U. S. A. 88, 395-399 [Abstract/Free Full Text]
5. Morel, A., O'Carroll, A.-M., Brownstein, M. J., and Lolait, S. J. (1992) Nature 356, 523-526 [CrossRef][Medline] [Order article via Infotrieve]
6. Kopin, A. S., Lee, Y.-M., McBride, E. W., Miller, L. J., Lu, M., Lin, H. Y., Kolakowski, L. F., Jr., and Beinborn, M. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 3605-3609 [Abstract/Free Full Text]
7. Wank, S. A., Pisegna, J. R., and de Weerth, A. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 8691-8695 [Abstract/Free Full Text]
8. Lee, Y.-M., Beinborn, M., McBride, E. W., Lu, M., Kolakowski, L. F., Jr., and Kopin, A. S. (1993) J. Biol. Chem. 268, 8164-8169 [Abstract/Free Full Text]
9. Viallet, J., Sharoni, Y., Frucht, H. Jensen, R. T., Minna, J. D., and Sausville, E. A. (1990) J. Clin. Invest. 86, 1904-1912
10. Trepel, J. B., Moyer, J. D., Heikkila, R., and Sausville, E. A. (1988) Biochem. J. 255, 403-410 [Medline] [Order article via Infotrieve]
11. Woll, P. J., and Rozengurt, E. (1989) Biochem. Biophys. Res. Commun. 164, 66-73 [CrossRef][Medline] [Order article via Infotrieve]
12. Bunn, P. A., Jr., Chan, D., Dienhart, D. G., Tolley, R., Tagawa, M., and Jewett, P. B. (1992) Cancer Res. 52, 24-31 [Abstract/Free Full Text]
13. Jiang, H., Wu, D., and Simon, M. I. (1994) J. Biol. Chem. 269, 7593-7596 [Abstract/Free Full Text]
14. Kozasa, T., Hepler, J. R., Smrcka, A. V., Simon, M. I., Rhee, S. G., Sternweis, P. C., and Gilman, A. G. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 9176-9180 [Abstract/Free Full Text]
15. Miller, A. D., and Buttimore, C. (1986) Mol. Cell. Biol. 6, 2895-2902 [Abstract/Free Full Text]
16. Markowitz, D., Goff, S., and Bank, A. J. (1988) Virology 62, 1120-1124
17. Qian, N.-X., Russell, M., Buhl, A. M., and Johnson, G. L. (1994) J. Biol. Chem. 269, 17417-17423 [Abstract/Free Full Text]
18. Gupta, S. K., Diez, E., Heasley, L. E., Osawa, S., and Johnson, G. L. (1990) Science 249, 662-666 [Abstract/Free Full Text]
19. Bunn, P. A., Jr., Chan, D., Stewart, J., Gera, L., Tolley, R., Jewett, P., Tagawa, M., Alford, C., Mochzuki, T., and Yanaihara, N. (1994) Cancer Res. 54, 3602-3610 [Abstract/Free Full Text]
20. Heasley, L. E., and Johnson, G. L. (1992) Mol. Biol. Cell 3, 545-553 [Abstract]
21. Hibi, M., Lin, A., Smeal, T., Minden, A., and Karin, M. (1993) Genes & Dev. 7, 2135-2148
22. Amatruda, T. T., III, Steele, D. A., Slepak, V. Z., and Simon, M. I. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 5587-5591 [Abstract/Free Full Text]
23. Johnson, B. E., Whang-Peng, J., Naylor, S. L., Zbar, B. B., Brauch, H., Lee, E., Simmons, A., Russell, E., Nam, M. H., and Gazdar, A. F. (1989) J. Natl. Cancer Inst. 81, 1223-1228 [Abstract/Free Full Text]
24. Wojcikiewicz, R. J. H., Furuichi, T., Nakade, S., Mikoshiba, K., and Nahorski, S. R. (1994) J. Biol. Chem. 269, 7963-7969 [Abstract/Free Full Text]
25. Minden, A., Lin, A., McMahon, M., Lange-Carter, C., Derijard, B., Davis, R. J., Johnson, G. L., and Karin, M. (1994) Science 266, 1719-1723 [Abstract/Free Full Text]
26. Derijard, B., Hibi, M., Wu, I.-H., Barrett, T., Su, B., Deng, T., Karin, M., and Davis, R. J. (1994) Cell 76, 1025-1037 [CrossRef][Medline] [Order article via Infotrieve]
27. Kyriakis, J. M., Banerjee, P., Nikolakaki, E., Dai, T., Rubie, E. A., Ahmed, M. F., Avruch, J., and Woodgett, J. R. (1994) Nature 369, 156-160 [CrossRef][Medline] [Order article via Infotrieve]
28. Mitsudomi, T., Viallet, J., Mulshine, J. L., Linnoila, R. I., Minna, J. D., and Gazdar, A. F. (1991) Oncogene 6, 1353-1362 [Medline] [Order article via Infotrieve]
29. Cerny, T., Barnes, D. M., Hasleton, P., Barber, P. V., Healy, K., Gullick, W., and Thatcher, N. (1986) Br. J. Cancer 54, 265-269 [Medline] [Order article via Infotrieve]
30. Kalinec, G., Nagaradi, A. J., Hermouet, S., Xu, N., and Gutkind, J. S. (1992) Mol. Cell. Biol. 12, 4687-4693 [Abstract/Free Full Text]
31. DeVivo, M., Chen, J., Codina, J., Iyengar, R. (1992) J. Biol. Chem. 267, 18263-18266 [Abstract/Free Full Text]
32. Lange-Carter, C. A., and Johnson, G. L. (1994) Science 265, 1458-1461 [Abstract/Free Full Text]

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				R. Higashita, L. Li, V. Van Putten, Y. Yamamura, F. Zarinetchi, L. Heasley, and R. A. Nemenoff Galpha 16 Mimics Vasoconstrictor Action to Induce Smooth Muscle alpha -Actin in Vascular Smooth Muscle Cells through a Jun-NH2-terminal Kinase-dependent Pathway J. Biol. Chem., October 10, 1997; 272(41): 25845 - 25850. [Abstract] [Full Text] [PDF]

				L. Butterfield, B. Storey, L. Maas, and L. E. Heasley c-Jun NH2-terminal Kinase Regulation of the Apoptotic Response of Small Cell Lung Cancer Cells to Ultraviolet Radiation J. Biol. Chem., April 11, 1997; 272(15): 10110 - 10116. [Abstract] [Full Text] [PDF]

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