NCI-H838 Cells Research Articles

Abstract A163: Exoribonuclease XRN1 is a therapeutic vulnerability in tumors with intrinsically elevated type I interferon signaling

Abstract Background: 5′→3′ exoribonuclease 1 (XRN1) degrades single stranded mRNA from the 5′→3′ direction and plays a key role in endogenous cellular mRNA turnover. In addition, XRN1 can degrade double-stranded RNA (dsRNA), and as such plays a role in innate immunity by prevention of dsRNA accumulation and pPKR induction in virus-infected cells. We identified XRN1 as a putative selective vulnerability in tumor cells with intrinsic elevation of a Type I Interferon Stimulated Gene (TISG) signature through analysis of publicly available CRISPR screen data across 483 tumor cell lines. We further explored the role of XRN1 in a set of lung cancer cell lines with differential TISG expression in order to validate XRN1 as a compelling target for oncology drug development. Materials and Methods: NCI-H1650, NCI-H1703, NCI-H1944, and NCI-H838 lung adenocarcinoma cell lines were infected with lentiviruses containing Cas9 and sgRNAs targeting XRN1. Non-targeting sgRNAs were used as negative controls. XRN1 knockout (KO) cells and controls were evaluated in proliferation, apoptosis, qPCR and western blot assays. Results: Consistent with a selective dependency on XRN1 in cells with high intrinsic interferon signaling, XRN1 KO via CRISPR leads to robust anti-proliferative effects in TISG high NCI-H1650 and NCI-H1703 cells, but not in TISG low NCI-H838 and NCI-H1944 cells. Annexin V staining of NCI-H1650 cells upon XRN1 KO demonstrates that apoptosis is induced in TISG high cells. XRN1 KO in the TISG high setting leads to robust upregulation of Interferon-β mRNA consistent with activation of the MDA5 pathway by elevation of cytoplasmic dsRNA. Similarly, XRN1 loss induces pPKR activation in TISG high, but not TISG low cells. As pPKR activation triggers translational shutdown, TISG high selective pPKR elevation is consistent with the cell death observed. Exogenous treatment with Interferon-β or dsRNA mimetic Poly I:C to induce elevated Type I Interferon expression sensitizes NCI-H838 cells to XRN1 KO, with effects on cell proliferation. Conclusions: Taken together, these results demonstrate a critical role of XRN1 in cancer cells with intrinsically elevated Type I Interferon signaling. Cell death is triggered via accumulation of dsRNA and downstream activation of the MDA5 and PKR innate immune pathways. These data suggest that XRN1, through its regulation of dsRNA burden, is a compelling oncology target for TISG high tumors. Conflict of Interests: All authors are current or former employees and shareholders of Accent Therapeutics, Inc. Citation Format: Maureen M Lynes, Sophie A Shen, Sunaina P Nayak, Brian A Sparling, Scott Ribich, Stephen J Blakemore, Serena J Silver. Exoribonuclease XRN1 is a therapeutic vulnerability in tumors with intrinsically elevated type I interferon signaling [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A163.

CDC20 and TRIB3 Upregulated by TFAP2C Facilitate Cell Proliferation in Non‐small Cell Lung Cancer Cells

In recent years, non‐small cell lung cancer (NSCLC) is the most serious cause of global cancer‐related mortality. To resolve this circumstance, many studies for identification of novel molecular targets have been conducted. In our previous investigation, a microarray analysis that associated with transcription factor activating enhancer‐binding protein 2C (TFAP2C) was carried out and we found out TFAP2C's oncogenic roles in NSCLC development. In the current study, we intended to reveal novel biomarkers for NSCLC, especially focused on several oncogenes transcriptionally regulated by TFAP2C. With the result of microarray analysis, cell division cycle 20 (CDC20) and tribbles pseudokinase 3 (TRIB3) were selected as promising oncogenes by transcriptionally upregulated by TFAP2C. In the treatment of TFAP2C‐specific siRNA in two NSCLC cell lines (NCI‐H292 and NCI‐H838 cells), we observed that mRNA and protein levels of CDC20 and TRIB3 were down‐regulated. In addition, when CDC20 or TRIB3 was overexpressed, cell viability was increased and reversely apoptosis of these cells was suppressed. Consequently, these results indicated that NSCLC tumorigenesis affected by two promising oncogenes, CDC20 and TRIB3, and they could act as potent markers to prognosis of NSCLC.Support or Funding InformationThis work was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2019R1C1C1009423).

MicroRNA-140's inhibition on the cell migration and invasion of non-small cell lung cancer by down-regulating Smad3 expression.

To investigate the effect of miR-140 on migration and invasion of non-small cell lung cancer (NSCLC) A549 cell and its regulatory mechanism. The NSCLC cell lines A549, H1650, NCI-H838, and normal lung epithelial cells BEAS-2B were purchased, and the expression of miR-140 and Smad3 in cells was detected by RT-PCR. MiR-140-inhibitor, miR-140-mimincs, miR-NC, sh-Smad3, Si-Smad3, and NC were transfected into A549 cells. Quantitative Real Time-Polymerase Chain Reaction (QRT-PCR) was used to detect the expression of miR-140 and Smad3. Transwell and cell scratch assay were used to detect cell invasion and migration. Dual-Luciferase report assay was used to study the relationship between mir-140 and Smad3. MiR-140 was lowly expressed and Smad3 was highly expressed in NSCLC cells. Cell researches showed that the overexpression of miR-140 can inhibit cell invasion and migration. The downregulation of Smad3 expression inhibits cell invasion and migration. Dual-Luciferase reporter assay showed that miR-140 is a Smad3 targeting site. MiR-140 can inhibit the invasion and migration of NSCLC cells by regulating Smad3, and it is expected to become a potential clinical target.

COX7A1 suppresses the viability of human non-small cell lung cancer cells via regulating autophagy.

COX7A1 is a subunit of cytochrome c oxidase, and plays an important role in the super‐assembly that integrates peripherally into multi‐unit heteromeric complexes in the mitochondrial respiratory chain. In recent years, some researchers have identified that COX7A1 is implicated in human cancer cell metabolism and therapy. In this study, we mainly explored the effect of COX7A1 on the cell viability of lung cancer cells. COX7A1 overexpression was induced by vector transfection in NCI‐H838 cells. Cell proliferation, colony formation and cell apoptosis were evaluated in different groups. In addition, autophagy was analyzed by detecting the expression level of p62 and LC3, as well as the tandem mRFP‐GFP‐LC3 reporter assay respectively. Our results indicated that the overexpression of COX7A1 suppressed cell proliferation and colony formation ability, and promoted cell apoptosis in human non‐small cell lung cancer cells. Besides, the overexpression of COX7A1 blocked autophagic flux and resulted in the accumulation of autophagosome via downregulation of PGC‐1α and upregulation of NOX2. Further analysis showed that the effect of COX7A1 overexpression on cell viability was partly dependent of the inhibition of autophagy. Herein, we identified that COX7A1 holds a key position in regulating the development and progression of lung cancer by affecting autophagy. Although the crosstalk among COX7A1, PGC‐1α and NOX2 needs further investigation, our study provides a novel insight into the therapeutic action of COX7A1 against human non‐small cell lung cancer.

Neurotensin receptors regulate transactivation of the EGFR and HER2 in a reactive oxygen species-dependent manner

Neurotensin is a 13 amino acid peptide which is present in many lung cancer cell lines. Neurotensin binds with high affinity to the neurotensin receptor 1, and functions as an autocrine growth factor in lung cancer cells. Neurotensin increases tyrosine phosphorylation of the epidermal growth factor receptor (EGFR) and the neurotensin receptor 1 antagonist SR48692 blocks the transactivation of the EGFR. Here the effects of reactive oxygen species on the transactivation of the EGFR and HER2 were investigated. Using non-small cell lung cancer (NSCLC) cell lines, neurotensin receptor 1 mRNA and protein were present. Using NCI–H838 cells, neurotensin or neurotensin8−13 but not neurotensin1−8 increased EGFR, ERK and HER2 tyrosine phosphorylation which was blocked by SR48692. Neurotensin addition to NCI–H838 cells increased significantly reactive oxygen species which was inhibited by SR48692, Tiron (superoxide scavenger) and diphenylene iodonium (DPI inhibits the ability of NADPH oxidase and dual oxidase enzymes to produce reactive oxygen species). Tiron or DPI impaired the ability of neurotensin to increase EGFR, ERK and HER2 tyrosine phosphorylation. Neurotensin stimulated NSCLC cellular proliferation whereas the growth was inhibited by SR48692, DPI or lapatinib (lapatinib is tyrosine kinase inhibitor of the EGFR and HER2). Lapatinib inhibited the ability of the neurotensin receptor 1 to transactivate the EGFR and HER2. The results indicate that neurotensin receptor 1 regulates the transactivation of the EGFR and HER2 in a reactive oxygen species-dependent manner.

Abstract 1007: Reactive oxygen species are essential for neurotensin receptors to regulate EGFR and HER2 transactivation

Abstract Neurotensin (NTS) is a 13 amino acid peptide which is present in many lung cancer cell lines (Moody et al., Life Sci 1985; 36: 1727). High expression of the NTS receptor 1 (R1) is associated with poor survival of non-small cell lung cancer (NSCLC) patients (Alfano et al., Clin Cancer Res 2010; 16: 4401). NTS stimulates but the NTSR1 antagonist SR48692 inhibits the proliferation of NSCLC cells (Moody et al., Life Sci 2014; 100: 25). NTSR1 regulates NSCLC proliferation by transactivation of the EGFR. The cellular signaling mechanisms of the NTSR1 were investigated using NSCLC cells. Using NCI-H838 or A549 cells, addition of NTS or NTS(8-13) but not NTS(1-8) increased tyrosine phosphorylation of P-EGFR, P-HER2 and P-ERK 4-, 3- and 2-fold, respectively. The increase in EGFR and HER2 transactivation caused by NTS addition to NSCLC cells was blocked by SR48692, gefitinib (EGFR tyrosine kinase inhibitor (TKI)), lapatinib (EGFR and HER2 TKI), N-acetyl cysteine ((NAC) is an antioxidant), tiron (reactive oxygen species (ROS) scavenger) or diphenyleneiodonium (DPI is an inhibitor of NOX and DUOX enzymes). NTS increased ROS in NSCLC cells which was inhibited by NAC, tiron or DPI. NTS or NTS(8-13) stimulate NSCLC colony growth but SR48692, gefitinib, lapatinib or DPI inhibit growth. The results indicate that the NTSR1 regulates in a ROS-dependent manner the formation of EGFR homodimers or EGFR-HER2 heterodimers in NSCLC cells. Citation Format: Terry W. Moody, Lingaku Lee, Robert T. Jensen. Reactive oxygen species are essential for neurotensin receptors to regulate EGFR and HER2 transactivation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1007.

PAC1 regulates receptor tyrosine kinase transactivation in a reactive oxygen species-dependent manner

Pituitary adenylate cyclase activating polypeptide (PACAP) is a growth factor for lung cancer cells. PACAP-27 or PACAP-38 binds with high affinity to non-small cell lung cancer (NSCLC) cells, causing elevated cytosolic Ca2+, increased proliferation and increased phosphorylation of extracellular regulated kinase (ERK) and the epidermal growth factor receptor (EGFR). The role of reactive oxygen species (ROS) was investigated in these processes. Addition of PACAP-38 to NCI-H838 or A549 cells increased the tyrosine phosphorylation of the EGFR, HER2 and ERK significantly by 4-, 3-, and 2-fold, respectively. The transactivation of the EGFR and HER2 was inhibited by gefitinib or lapatinib (tyrosine kinase inhibitors), PACAP (6–38) (PAC1 antagonist), N-acetylcysteine (NAC is an anti-oxidant) or dipheyleneiodonium (DPI is an inhibitor of Nox and Duox enzymes). PACAP-38 addition to NSCLC cells increased ROS which was inhibited by PACAP (6–38), NAC or DPI. Nox1, Nox2, Nox3, Nox4, Nox5, Duox1 and Duox2 mRNA was present in many NSCLC cell lines. PACAP-38 stimulated the growth of NSCLC cells whereas PACAP (6–38), gefitinib or DPI inhibited proliferation. The results show that ROS are essential for PAC1 to regulate EGFR and HER2 transactivation as well as proliferation of NSCLC cells.

MiR-137 inhibits the proliferation of human non-small cell lung cancer cells by targeting SRC3.

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. The results of the present study demonstrate that high expression of microRNA (miR)-137 and low expression of steroid receptor coactivator-3 (SRC3) had a significant negative correlation in 40 NSCLC tissue samples. In addition, cell colony formation and proliferation was significantly reduced in miR-137-transfected A549 and NCI-H838 cells compared with scramble-transfected NSCLC cell lines. miR-137 was identified to induce G1/S cell cycle arrest and dysregulate the mRNA expression of cell cycle-associated proteins (proliferating cell nuclear antigen, cyclin E, cyclin A1, cyclin A2 and p21) in NSCLC cells. Notably, miR-137 could significantly suppress SRC3 3' untranslated region (UTR) luciferase-reporter activity, an effect that was not detectable when the putative 3'-UTR target-site was mutated, further clarifying the molecular mechanisms underlying the role of miR-137 in NSCLC. In conclusion, the results of the present study suggest that miR-137 suppresses NSCLC cell proliferation by partially targeting SRC3.

Endothelin causes transactivation of the EGFR and HER2 in non-small cell lung cancer cells

Endothelin (ET)-1 is an important peptide in cancer progression stimulating cellular proliferation, tumor angiogenesis and metastasis. ET-1 binds with high affinity to the ETA receptor (R) and ETBR on cancer cells. High levels of tumor ET-1 and ETAR are associated with poor survival of lung cancer patients. Here the effects of ET-1 on epidermal growth factor (EGF)R and HER2 transactivation were investigated using non-small cell lung cancer (NSCLC) cells. ETAR mRNA was present in all 10 NSCLC cell lines examined. Addition of ET-1 to NCI-H838 or H1975 cells increased EGFR, HER2 and ERK tyrosine phosphorylation within 2min. The increase in EGFR and HER2 transactivation caused by ET-1 addition to NSCLC cells was inhibited by lapatinib (EGFR and HER2 tyrosine kinase inhibitor (TKI)), gefitinib (EGFR TKI), ZD4054 or BQ-123 (ETAR antagonist), GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor) or Tiron (superoxide scavenger). ET-1 addition to NSCLC cells increased cytosolic Ca2+ and reactive oxygen species. ET-1 increased NSCLC clonal growth, whereas BQ123, ZD4054, lapatinib or gefitinib inhibited proliferation. The results indicate that ET-1 may regulate NSCLC cellular proliferation in an EGFR- and HER2-dependent manner.

Clinically relevant concentrations of lidocaine and ropivacaine inhibit TNFα-induced invasion of lung adenocarcinoma cells in vitro by blocking the activation of Akt and focal adhesion kinase

Matrix-metalloproteinases (MMP) and cancer cell invasion are crucial for solid tumour metastasis. Important signalling events triggered by inflammatory cytokines, such as tumour necrosis factor α (TNFα), include Src-kinase-dependent activation of Akt and focal adhesion kinase (FAK) and phosphorylation of caveolin-1. Based on previous studies where we demonstrated amide-type local anaesthetics block TNFα-induced Src activation in malignant cells, we hypothesized that local anaesthetics might also inhibit the activation and/or phosphorylation of Akt, FAK and caveolin-1, thus attenuating MMP release and invasion of malignant cells. NCI-H838 lung adenocarcinoma cells were incubated with ropivacaine or lidocaine (1 nM-100 µM) in absence/presence of TNFα (20 ng ml(-1)) for 20 min or 4 h, respectively. Activation/phosphorylation of Akt, FAK and caveolin-1 were evaluated by Western blot, and MMP-9 secretion was determined by enzyme-linked immunosorbent assay. Tumour cell migration (electrical wound-healing assay) and invasion were also assessed. Ropivacaine (1 nM-100 μM) and lidocaine (1-100 µM) significantly reduced TNFα-induced activation/phosphorylation of Akt, FAK and caveolin-1 in NCI-H838 cells. MMP-9 secretion triggered by TNFα was significantly attenuated by both lidocaine and ropivacaine (half-maximal inhibitory concentration [IC50]=3.29×10(-6) M for lidocaine; IC50=1.52×10(-10) M for ropivacaine). The TNFα-induced increase in invasion was completely blocked by both lidocaine (10 µM) and ropivacaine (1 µM). At clinically relevant concentrations both ropivacaine and lidocaine blocked tumour cell invasion and MMP-9 secretion by attenuating Src-dependent inflammatory signalling events. Although determined entirely in vitro, these findings provide significant insight into the potential mechanism by which local anaesthetics might diminish metastasis.

Epo Receptors Are Not Detectable in Primary Human Tumor Tissue Samples

Erythropoietin (Epo) is a cytokine that binds and activates an Epo receptor (EpoR) expressed on the surface of erythroid progenitor cells to promote erythropoiesis. While early studies suggested EpoR transcripts were expressed exclusively in the erythroid compartment, low-level EpoR transcripts were detected in nonhematopoietic tissues and tumor cell lines using sensitive RT-PCR methods. However due to the widespread use of nonspecific anti-EpoR antibodies there are conflicting data on EpoR protein expression. In tumor cell lines and normal human tissues examined with a specific and sensitive monoclonal antibody to human EpoR (A82), little/no EpoR protein was detected and it was not functional. In contrast, EpoR protein was reportedly detectable in a breast tumor cell line (MCF-7) and breast cancer tissues with an anti-EpoR polyclonal antibody (M-20), and functional responses to rHuEpo were reported with MCF-7 cells. In another study, a functional response was reported with the lung tumor cell line (NCI-H838) at physiological levels of rHuEpo. However, the specificity of M-20 is in question and the absence of appropriate negative controls raise questions about possible false-positive effects. Here we show that with A82, no EpoR protein was detectable in normal human and matching cancer tissues from breast, lung, colon, ovary and skin with little/no EpoR in MCF-7 and most other breast and lung tumor cell lines. We show further that M-20 provides false positive staining with tissues and it binds to a non-EpoR protein that migrates at the same size as EpoR with MCF-7 lysates. EpoR protein was detectable with NCI-H838 cells, but no rHuEpo-induced phosphorylation of AKT, STAT3, pS6RP or STAT5 was observed suggesting the EpoR was not functional. Taken together these results raise questions about the hypothesis that most tumors express high levels of functional EpoR protein.

MiR-449c targets c-Myc and inhibits NSCLC cell progression

MicroRNAs (miRNA) play an important role in tumorigenesis, proliferation, and differentiation. Altered miRNA expression in cancer indicates that miRNAs can function as tumor suppressors or oncogenes. MiR-449c downregulation in non-small cell lung cancer (NSCLC) compared with normal lung tissues was investigated in this study. NSCLC cell proliferation and invasion assays indicate that transfection of miR-449c expression plasmid inhibits the proliferation and invasion ability of NCI-H23 and NCI-H838 cells. In addition, miR-449c overexpression could suppress tumor growth in vivo. Morever, c-Myc was identified as a direct target gene of miR-449c. These findings clearly suggest that miR-449c downregulation and c-Myc amplification may be involved in the development of NSCLC.

PYK-2 is Tyrosine Phosphorylated after Activation of Pituitary Adenylate Cyclase Activating Polypeptide Receptors in Lung Cancer Cells

The signal transduction mechanisms of pituitary adenylate cyclase activating polypeptide (PACAP) were investigated in lung cancer cells. Previously, PACAP-27 addition to NCI-H838 cells increased phosphatidylinositol turnover and intracellular cAMP leading to proliferation of lung cancer cells. Also, PACAP receptors (PAC1) regulated the tyrosine phosphorylation of ERK, focal adhesion kinase, and paxillin. In this communication, the effects of PACAP on cytosolic Ca(2+) and PYK-2 tyrosine phosphorylation were investigated. PACAP-27 increased cytosolic Ca(2+) within seconds after addition to FURA-2 AM loaded NCI-H838 cells. The increase in cytosolic Ca(2+) caused by PACAP was inhibited by PACAP(6-38) (PAC1 antagonist), U73122 (phospholipase C inhibitor), or BAPTA (calcium chelator), but not H89 (PKA inhibitor). PACAP-38, but not vasoactive intestinal peptide (VIP), addition to NCI-H838 or H1299 cells significantly increased the tyrosine phosphorylation of PYK-2 after 2 min. The increase in PYK-2 tyrosine phosphorylation caused by PACAP was inhibited by PACAP(6-38), U73122, or BAPTA, but not H89. The results suggest that PAC1 regulates PYK-2 tyrosine phosphorylation in a calcium-dependent manner.

Abstract 1091: Cannabinoids inhibit epidermal growth factor receptor transactivation in lung cancer cells

Abstract The cannabinoid receptors CB1 and CB2 are present on non-small cell lung cancer (NSCLC) biopsy specimens (Preet et al., 2011, Cancer Prev. Res. 4:65). CP55,940 and Win55,212-2 are mixed agonists which stimulate CB1 and CB2 cannabinoid receptors. G-protein coupled receptors (GPCR) for pituitary adenylate cyclase activating polypeptide (PACAP) regulate epidermal growth factor receptor (EGFR) tyrosine phosphorylation in NSCLC cells. Here the ability of cannabinoids to alter EGFR transactivation was investigated. PACAP stimulated EGFR tyrosine phosphorylation (PY1068) 4-fold using NCI-H838 and H1299 cells. CP55,940 and Win55,212-2 inhibited the ability of PACAP to increase EGFR tyrosine phosphorylation in lung cancer cells. By Western blot, cell lines NCI-H838 and NCI-H1299 had both CB1 and CB2 receptors. PACAP increased cAMP levels in NCI-H838 cells and CP55,940 inhibited the increase in cAMP caused by PACAP. In contrast, PACAP increased cytosolic Ca2+ in lung cancer cells, but CP55,940 did not alter the ability of PACAP to increase calcium in lung cancer cells. These results suggest that CP55,940 may inhibit adenylyl cyclase activity but not phosphatidylinositol turnover caused by addition of PACAP to lung cancer cells. Previously we found that PACAP increased tyrosine phosphorylation of focal adhesion kinase, paxillin and ERK in lung cancer cells (Moody et al., 2002, Reg. Peptides 109:135). CP55,940 inhibited the increase in tyrosine phosphorylation of focal adhesion kinase, paxillin and ERK caused by PACAP addition to lung cancer cells. Also, CP55.940 and Win55,212-2 inhibited the growth of NCI-H1299 and NCI-H838 cells. CP55,940 potentiated the growth inhibitory effects of gefitinib, an EGFR tyrosine kinase inhibitor. These results indicate that cannabinoids inhibit EGFR transactivation in lung cancer cells and potentiate gefitinib cytotoxicity. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1091. doi:1538-7445.AM2012-1091

Pituitary Adenylate Cyclase-Activating Polypeptide Causes Tyrosine Phosphorylation of the Epidermal Growth Factor Receptor in Lung Cancer Cells

Pituitary adenylate cyclase-activating polypeptide (PACAP) is an autocrine growth factor for some lung cancer cells. The activated PACAP receptor (PAC1) causes phosphatidylinositol turnover, elevates cAMP, and increases the proliferation of lung cancer cells. PAC1 and epidermal growth factor receptor (EGFR) are present in non-small-cell lung cancer (NSCLC) cells, and the growth of NSCLC cells is inhibited by the PAC1 antagonist PACAP(6-38) and the EGFR tyrosine kinase inhibitor gefitinib. Here, the ability of PACAP to transactivate the EGFR was investigated. Western blot analysis indicated that the addition of PACAP but not the structurally related vasoactive intestinal peptide increased EGFR tyrosine phosphorylation in NCI-H838 or H345 cells. PACAP-27, in a concentration-dependent manner, increased EGFR transactivation 4-fold 2 min after addition to NCI-H838 cells. The ability of 100 nM PACAP-27 to increase EGFR or extracellular signal-regulated kinase tyrosine phosphorylation in NCI-H838 cells was inhibited by PACAP(6-38), gefitinib, 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine (PP2; Src inhibitor), (R)-N4-hydroxy-N1-[(S)-2-(1H-indol-3-yl)-1-methylcarbamoyl-ethyl]-2-isobutyl-succinamide (GM6001; matrix metalloprotease inhibitor), or antibody to transforming growth factor α (TGFα). By enzyme-linked immunosorbent assay, PACAP addition to NCI-H838 cells increased TGFα secretion into conditioned media. EGFR transactivation caused by the addition of PACAP to NCI-H838 cells was inhibited by N-acetyl-cysteine (antioxidant), tiron (superoxide scavenger), diphenylene iodonium (NADPH oxidase inhibitor), or 1-[6-[[(17β)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122; phospholipase C inhibitor), but not N-[2-[[3-(4-bromophenyl)-2-propenyl]amino]ethyl]-5-isoquinolinesulfonamide (H89; protein kinase A inhibitor). PACAP addition to NCI-H838 cells significantly increased reactive oxygen species, and the increase was inhibited by tiron. The results indicate that PACAP causes transactivation of the EGFR in NSCLC cells in an oxygen-dependent manner that involves phospholipase C but not protein kinase A.

Pituitary Adenylate Cyclase-Activating Polypeptide Causes Increased Tyrosine Phosphorylation of Focal Adhesion Kinase and Paxillin

The effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin were investigated using lung cancer cells. Addition of PACAP-27 or PACAP-38 but not vasoactive intestinal peptide to NCI-H838 or NCI-H1299 human lung cancer cells significantly increased the tyrosine phosphorylation of FAK or paxillin. The increase in FAK or paxillin tyrosine phosphorylation caused by addition of PACAP-27 to NCI-H838 cells was inhibited by PACAP(6-38), a PAC1-receptor (R) antagonist. The increase in FAK or paxillin tyrosine phosphorylation caused by 100 nM PACAP-27 was maximal 2 min after addition to NCI-H838 cells. The effects of PACAP at stimulating FAK and paxillin tyrosine phosphorylation were reversed by cytochalasin D and genistein which inhibit actin polymerization and tyrosine kinase activity, respectively. The effects of PACAP at stimulating FAK and paxillin tyrosine phosphorylation were reversed by U-73122 but not H89 which inhibit phospholipase C and protein kinase A, respectively. The results show that PAC1-R regulates FAK and paxillin tyrosine phosphorylation in lung cancer cells as a result of increased phosphatidylinositol turnover but not adenylyl cylase stimulation.

Abstract 4534: Lung cancer epidermal growth factor receptors are transactivated by neurotensin

Abstract Neurotensin (NT) is an autocrine growth factor for some lung cancer cells (Moody et al., Life Sci 36:1727(1985)). The NTS1 receptor (R), which causes phosphatidylinositol turnover, elevates cytosolic Ca2+ and increases proliferation of lung cancer cells, is blocked by SR48692 (Moody et al., Peptides 22:109 (2001)). Previously we found that NT caused tyrosine phosphorylation of focal adhesion kinase in non-small cell lung cancer (NSCLC) cells (Leyton et al., Eur. J. Pharm. 442:179 (2002)). Here the ability of NT to cause tyrosine phosphorylation of the epidermal growth factor (EGF)R in lung cancer cells was investigated. NT and NT8-13 but not NT1-8 caused tyrosine phosphorylation of the EGFR using NCI-H1299 or H345 cells. The transactivation of the EGFR caused by NT addition to lung cancer cells was inhibited by SR48692 (NTS1R antagonist) or gefitinib (EGFR tyrosine kinase inhibitor). NT significantly increased EGFR tyrosine phosphorylation (4-fold) after 0.5 min in a dose-dependent manner. The ability of NT to increase EGFR or ERK tyrosine phosphorylation was inhibited by PP2 (Src inhibitor), GM6001 (matrix metalloprotease inhibitor), or antibody to transforming growth factor (TGF) α. By ELISA, NT stimulated significantly the release of TGFα from NCI-H838 cells. NT stimulation of EGFR tyrosine phosphorylation was inhibited by addition of N-acetylcysteine (anti-oxidant), tiron (superoxide scavenger), DPI (NADPH oxidase inhibitor). These results indicate that NT causes transactivation of lung cancer EGFR in an oxygen-dependent, Src-dependent manner resulting in activation of matrix metalloprotease and release of TGFα. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4534. doi:10.1158/1538-7445.AM2011-4534

Abstract 4115: Pituitary adenylate cyclase activating polypeptide causes the transactivation of epidermal growth factor receptors in lung cancer cells

Abstract Pituitary adenylate cyclase activating polypeptide (PACAP) is an autocrine growth factor for some lung cancer cells. The activated PAC1 receptor (R) causes phosphatidylinositol turnover, elevates cyclic AMP and increases proliferation of lung cancer cells (Zia et al., Cancer Res. 55:4886 (1995)). PAC1R mRNA is present in NSCLC cell line NCI-H838, which has epidermal growth factor (EGF)R. PACAP or EGF stimulated the proliferation of NCI-H838 cells whereas PACAP(6-38) or gefitinib inhibited growth. To investigate the cellular basis of these actions, the ability of PACAP to alter EGFR function was investigated using NSCLC cells. PACAP, but not the closely related vasoactive intestinal peptide (VIP) significantly increased EGFR tyrosine phosphorylation (4-fold) 2 min after addition to NCI-H838 cells. The ability of PACAP to increase EGFR or ERK tyrosine phosphorylation was inhibited by PACAP(6-38) (PAC1R antagonist), gefitinib (EGFR tyrosine kinase inhibitor), PP2 (Src inhibitor), GM6001 (matrix metalloprotease inhibitor), or antibody to transforming growth factor (TGF) α. These results suggest that PACAP may increase the rate of release of TGFα from NCI-H838 cells, resulting in elevated EGFR tyrosine phosphorylation. PACAP stimulation of EGFR tyrosine phosphorylation was inhibited by addition of N-acetylcysteine (anti-oxidant), tiron (superoxide scavenger), DPI (NADPH oxidase inhibitor) or U-73122 (Phospholipase C inhibitor) but not H89 (protein kinase A inhibitor) to NCI-H838 cells. These results indicate that PACAP, a growth factor for NSCLC, causes transactivation of the EGFR in an oxygen-dependent manner that involves phospholipase C but not protein kinase A. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4115.

Resveratrol Enhances Radiosensitivity of Human Non-Small Cell Lung Cancer NCI-H838 Cells Accompanied by Inhibition of Nuclear Factor-Kappa B Activation

Resveratrol, a polyphenol in red wine, possesses many pharmacological activities including cardioprotection, chemoprevention, anti-tumor effects, and nuclear factor-kappa B (NF-kappaB) inactivation. The present study was designed to evaluate the effects and possible mechanism of resveratrol in enhancing radiosensitivity of lung cancer cells. Human non-small cell lung cancer NCI-H838 cells were irradiated with or without resveratrol pretreatment. The surviving fraction and sensitizer enhancement ratio (SER) were estimated by using a colony formation assay and linear-quadratic model. The cell-cycle distribution was evaluated by using propidium iodide staining and flow cytometry. An ELISA-based assay with immobilized oligonucleotide was performed to assess the DNA binding activity of NF-kappaB. Resveratrol had no direct growth-inhibitory effect on NCI-H838 cells treated for 24 hours with doses up to 25 microM. Pretreatment with resveratrol significantly enhanced cell killing by radiation, with an SER up to 2.2. Radiation activated NF-kappaB, an effect reversed by resveratrol pretreatment. Resveratrol resulted in a decrease of cells in the G0/G1 phase and an increase in the S phase. Our results demonstrate that resveratrol enhances the radiosensitivity of NCI-H838 cells accompanied by NF-kappaB inhibition and S-phase arrest.

Bombesin activates MAP kinase in non-small cell lung cancer cells

The effects of bombesin (BB) on mitogen activated protein (MAP) kinase were investigated using non-small cell lung cancer (NSCLC) cells. By Western blot, both 42 and 44 kDalton forms of MAP kinase were present in NCI-H1299 and NCI-H838 cells. Addition of BB to NCI-H1299 cells resulted in phosphorylation of the MAP kinase substrate myelin basic protein (MBP). Phosphorylation of MBP was maximal 6 min after the addition of 10 nM BB to NCI-H1299 cells. Addition of gastrin releasing peptide (GRP) or GRP14–27 but not GRP1–16 to NCI-H1299 cells caused MBP phosphorylation. The effects of BB were inhibited by BW2258U89, a BB receptor antagonist, and PD98059, a MAP kinase kinase inhibitor. Also, PD98059 inhibited the clonal growth of NCI-H1299 cells. These data suggest that MAP kinase may be an important regulatory enzyme in NSCLC.