Abstract A145: SHP2 inhibition restores sensitivity to ALK inhibitors in resistant ALK-rearranged NSCLC

Most anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung tumors initially respond to small-molecule ALK inhibitors, but drug resistance often develops. After tumors develop resistance to highly potent 2nd-generation ALK inhibitors, approximately half harbor ALK resistance mutations, while the other half have other mechanisms of resistance. The latter often have activation of at least one of several different tyrosine kinases driving resistance. Such tumors are not expected to respond to the 3rd-generation ALK inhibitor, lorlatinib, which is able to overcome all clinically identified ALK resistance mutations, and further therapeutic options are limited. Herein, we deployed an shRNA screen of 1000 genes in multiple ALK inhibitor-resistant patient-derived cells (PDC) to discover sensitizers to ALK inhibition. This approach identified SHP2, a non-receptor protein tyrosine phosphatase, as a common targetable resistance node in multiple PDCs. SHP2 provides a parallel survival input downstream of multiple tyrosine kinases that promote resistance to ALK inhibitors. The recently discovered small-molecule SHP2 inhibitor, SHP099, in combination with the ALK TKI (tyrosine kinase inhibitor), ceritinib, halted the growth of resistant PDCs by preventing compensatory RAS and ERK1/2 reactivation. These findings suggest that combined ALK and SHP2 inhibition may be a promising therapeutic strategy for resistant cancers driven by several different ALK-independent resistance mechanisms.

Citation Format: Leila Dardaei, Hui Qin Wang, Manrose Singh, Paul Fordjour, Satoshi Yoda, Grainne Kerr, Jinsheng Liang, Yichen Cao, Yan Chen, Justin Gainor, Luc Friboulet, Ibiayi Dagogo-Jack, David Myers, Emma Labrot, David Ruddy, Melissa Parks, Dana Lee, Richard DiCecca, Susan Moody, Huaixiang Hao, Morvarid Mohseni, Matthew LaMarche, Juliet Williams, Keith Hoffmaster, Giordano Caponigro, Alice Shaw, Aaron Hata, Cyril Benes, Fang Li, Jeffrey Engelman. SHP2 inhibition restores sensitivity to ALK inhibitors in resistant ALK-rearranged NSCLC [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A145.

Translucent, hydrophobic, and mechanically tough aerogels constructed from trimethylsilylated chitosan nanofibers

Cross-linking and trimethylsilylation successfully block off the hydrophilic NH₂ and OH groups in chitosan nanofibers to produce a waterproof nanofibrous aerogel while keeping its nanoscale structural homogeneity intact. The unique microstructure of a three-dimensionally entangled nanofiber network exhibiting a combination of translucency, hydrophobicity, and non-brittleness is described.

Patterns of Metastatic Spread and Mechanisms of Resistance to Crizotinib in ROS1-Positive Non-Small-Cell Lung Cancer

PURPOSE

The ROS1 tyrosine kinase is activated through ROS1 gene rearrangements in 1-2% of non-small cell lung cancer (NSCLC), conferring sensitivity to treatment with the ALK/ROS1/MET inhibitor crizotinib. Currently, insights into patterns of metastatic spread and mechanisms of crizotinib resistance among ROS1-positive patients are limited.

PATIENTS AND METHODS

We reviewed clinical and radiographic imaging data of patients with ROS1- and ALK-positive NSCLC in order to compare patterns of metastatic spread at initial metastatic diagnosis. To determine molecular mechanisms of crizotinib resistance, we also analyzed repeat biopsies from a cohort of ROS1-positive patients progressing on crizotinib.

RESULTS

We identified 39 and 196 patients with advanced ROS1- and ALK-positive NSCLC, respectively. ROS1-positive patients had significantly lower rates of extrathoracic metastases (ROS1 59.0%, ALK 83.2%, P=0.002), including lower rates of brain metastases (ROS1 19.4%, ALK 39.1%; P = 0.033), at initial metastatic diagnosis. Despite similar overall survival between ALK- and ROS1-positive patients treated with crizotinib (median 3.0 versus 2.5 years, respectively; P=0.786), ROS1-positive patients also had a significantly lower cumulative incidence of brain metastases (34% vs. 73% at 5 years; P<0.0001). Additionally, we identified 16 patients who underwent a total of 17 repeat biopsies following progression on crizotinib. ROS1 resistance mutations were identified in 53% of specimens, including 9/14 (64%) non-brain metastasis specimens. ROS1 mutations included: G2032R (41%), D2033N (6%), and S1986F (6%).

CONCLUSIONS

Compared to ALK rearrangements, ROS1 rearrangements are associated with lower rates of extrathoracic metastases, including fewer brain metastases, at initial metastatic diagnosis. ROS1 resistance mutations, particularly G2032R, appear to be the predominant mechanism of resistance to crizotinib, underscoring the need to develop novel ROS1 inhibitors with activity against these resistant mutants.

Abstract 1007: SHP2 inhibition restores sensitivity to ALK inhibition in resistant ALK-rearranged non-small cell lung cancer (NSCLC)

Despite development of highly potent and selective inhibitors (e.g., ceritinib, alectinib, lorlatinib) targeting anaplastic lymphoma kinase (ALK), resistance invariably develops and limits the efficacy of these inhibitors in the clinic. The major classes of resistance are on-target genetic alterations (e.g., secondary ALK kinase domain mutations) and activation of alternative or bypass signaling pathways. While most patients are responsive to sequential treatment with two or more ALK inhibitors, ALK-independent resistance eventually emerges and leads to failure of further ALK-directed monotherapy. We used a synthetic lethal pooled shRNA screen to discover loss-of-function events that could sensitize resistant patient-derived cell lines to ALK inhibition. In addition to identifying known bypass targets such as FGFR, EGFR and SRC, we also identified PTPN11 (which encodes SHP2, a non-receptor protein tyrosine phosphatase that modulates signaling downstream of growth factor receptors) as a common hit shared by cell lines exhibiting different mechanisms of bypass activation. In parallel with the shRNA screen, we also performed a high throughput combination compound screen in the same patient-derived models, and identified activation of the same bypass signaling pathways. We showed that the highly potent and selective small-molecule SHP2 inhibitor SHP099 could sensitize resistant cell lines to ALK inhibition. In biochemical studies, co-targeting of ALK and SHP2 overcame resistance mediated by ALK-independent bypass mechanisms by decreasing RAS-GTP loading potential of cells and inhibiting phospho-ERK rebound. These results suggest that dual ALK and SHP2 inhibition may represent a new therapeutic strategy for ALK-positive patients, whose lung cancers have evolved ALK-independent mechanisms of resistance, including activation of bypass signaling pathways.

Citation Format: Leila Dardaei, Hui Qin Wang, Paul Fordjour, Manrose Singh, Grainne Kerr, Satoshi Yoda, Jinsheng Liang, Yichen Cao, Yan Chen, Justin F. Gainor, Luc Friboulet, Ibiayi Dagogo-Jack, David T. Myers, Emma Labrot, David Ruddy, Melissa Parks, Dana Lee, Richard H. DiCecca, Susan Moody, Huaixiang Hao, Morvarid Mohseni, Matthew LaMarche, Juliet Williams, Keith Hoffmaster, Giordano Caponigro, Cyril H. Benes, Alice T. Shaw, Aaron N. Hata, Fang Li, Jeffrey A. Engelman. SHP2 inhibition restores sensitivity to ALK inhibition in resistant ALK-rearranged non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1007. doi:10.1158/1538-7445.AM2017-1007

Abstract 3144: Prediction of ALK mutations associated with acquired resistance to lorlatinib

Anaplastic lymphoma kinase (ALK) rearrangements are important therapeutic targets in non-small cell lung cancer. They are currently treated with the first-generation ALK inhibitor crizotnib followed by more potent, second-generation ALK inhibitors, such as ceritinib, alectinib, or brigatinib. We reported different spectrums of ALK resistance mutations in the biopsies from patients progressing on these drugs. G1202R mutation was found more frequently after treatment with second generation ALK inhibitors. In addition to these drugs, the third-generation ALK inhibitor lorlatinib is currently being evaluated in phase 2 clinical trial. Ba/F3 models indicated that all single ALK mutants are sensitive to lorlatinib and some compound ALK mutations are resistant to lorlatinib. In this study, we performed accelerated mutagenesis screen on Ba/F3 models to predict the resistance mutations which potentially emerge in the patients treated with lorlatinib. Briefly, Ba/F3 cells expressing wild type EML4-ALK or mutant EML4-ALK containing C1156Y, F1174C, L1196M, G1202R, or G1269A were exposed to N-ethyl-N-nitrosourea (ENU). After a 24-hour incubation in normal media, the cells were seeded in 96-well plates and incubated in lorlatinib for 4 weeks. ALK kinase domain was sequenced in clones growing in lorlatinib to identify possible new mutations. As a result, Ba/F3 cells harboring wild type EML4-ALK did not show any mutation on ALK kinase domain. Crizotinib was used as a control to validate the efficiency of mutagenesis. We identified eight different mutations in clones growing in crizotinib, and those were reflecting the spectrum of mutations in the crizotinib-treated patients. Ba/F3 cells with mutant EML4-ALK showed additional compound mutations after incubation with lorlatinib. Those mutations included L1196M + L1198F and G1202R + L1198F which showed high resistance to lorlatinib in Ba/F3 models. Ba/F3 cells with different mutant EML4-ALK showed a distinct spectrum and different frequency of additional mutations. In conclusion, this study predicted that no single mutation would emerge to confer resistance to lorlatinib. Thus, compound mutations and ALK-independent mechanisms become essential mechanisms for lorlatinib resistance.

Citation Format: Satoshi Yoda, Leila Dardaei, Manrose Singh, Jeffrey A. Engelman, Alice T. Shaw, Aaron N. Hata. Prediction of ALK mutations associated with acquired resistance to lorlatinib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3144. doi:10.1158/1538-7445.AM2017-3144

Erlotinib as second- or third-line treatment in elderly patients with advanced non-small cell lung cancer: Keio Lung Oncology Group Study 001 (KLOG001)

The aim of this study was to assess the efficacy and safety of erlotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), as second- or third-line treatment for elderly Japanese patients with non-small-cell lung cancer (NSCLC). The patients eligible for this phase II trial were aged ≥70 years, had stage III/IV or recurrent NSCLC, and had previously received 1 or 2 chemotherapy regimens that did not include EGFR-TKIs. The patients received erlotinib at a dose of 150 mg/day. The primary endpoint was overall response rate (ORR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS) and toxicity. A total of 38 patients with a median age of 76 years were enrolled. The majority of the patients were men (66%), had an Eastern Cooperative Oncology Group performance status of 1 (58%), stage IV disease (66%) and adenocarcinoma (74%). Of the 35 patients, 13 (34%) had tumors with EGFR mutations. The ORR was 26.3% (95% confidence interval: 12.1-40.5%) and the disease control rate was 47.4%. The median PFS was 3.7 months and the median OS was 17.3 months. The grade 3 adverse events observed included rash (13%), diarrhea (5%), interstitial pneumonitis (5%), anorexia (3%) and gastrointestinal bleeding (3%). Grade 4 or 5 adverse events were not observed. The median OS did not differ significantly between patients aged <75 years (14.9 months) and those aged ≥75 years (19.0 months; P=0.226). Therefore, erlotinib was found to be effective and well-tolerated in elderly patients with previously treated NSCLC.

Molecular Mechanisms of Resistance to First- and Second-Generation ALK Inhibitors in ALK-Rearranged Lung Cancer

Advanced, anaplastic lymphoma kinase (ALK)-positive lung cancer is currently treated with the first-generation ALK inhibitor crizotinib followed by more potent, second-generation ALK inhibitors (e.g., ceritinib and alectinib) upon progression. Second-generation inhibitors are generally effective even in the absence of crizotinib-resistant ALK mutations, likely reflecting incomplete inhibition of ALK by crizotinib in many cases. Herein, we analyzed 103 repeat biopsies from ALK-positive patients progressing on various ALK inhibitors. We find that each ALK inhibitor is associated with a distinct spectrum of ALK resistance mutations and that the frequency of one mutation, ALK^G1202R, increases significantly after treatment with second-generation agents. To investigate strategies to overcome resistance to second-generation ALK inhibitors, we examine the activity of the third-generation ALK inhibitor lorlatinib in a series of ceritinib-resistant, patient-derived cell lines, and observe that the presence of ALK resistance mutations is highly predictive for sensitivity to lorlatinib, whereas those cell lines without ALK mutations are resistant.

SIGNIFICANCE

Secondary ALK mutations are a common resistance mechanism to second-generation ALK inhibitors and predict for sensitivity to the third-generation ALK inhibitor lorlatinib. These findings highlight the importance of repeat biopsies and genotyping following disease progression on targeted therapies, particularly second-generation ALK inhibitors. Cancer Discov; 6(10); 1118-33. ©2016 AACRSee related commentary by Qiao and Lovly, p. 1084This article is highlighted in the In This Issue feature, p. 1069.

A phase II study of biweekly paclitaxel and carboplatin in elderly patients with advanced non-small cell lung cancer

PURPOSE

The number of elderly patients with advanced non-small cell lung cancer (NSCLC) is increasing. Although several studies have suggested the benefit of chemotherapy with a platinum doublet for elderly patients with advanced NSCLC, this treatment is still controversial in this age group. To evaluate the efficacy and tolerability of combination chemotherapy with biweekly paclitaxel and carboplatin for elderly patients with advanced NSCLC, we conducted a multicenter, non-randomized, open label, phase II trial.

METHODS

We recruited patients aged ≥70 years with clinical stage IIIB and IV NSCLC and ECOG performance status (PS) of 0-2. Patients received paclitaxel (90 mg/m(2)) and carboplatin (AUC = 2.5) on day 1 and 15, every 4 weeks. The primary endpoint was overall response rate (ORR), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Sixty-five patients (median age 79 years; range 70-87 years) were enrolled. Forty-nine patients were men, and 48 were stage IV. The PS was 0, 1, and 2 in 28, 33, and 4 patients, respectively. The histological type of NSCLC was non-squamous in 69.3 % and squamous cell carcinoma in 30.7 % of patients. The median number of treatment cycles was 3 (range 1-6). The response rate was 29.4 % (95 % CI 18.7-43.0), and the disease control rate was 78.0 % (95 % CI 64.8-87.2). Median PFS and OS were 3.8 months (95 % CI 1.9-5.3) and 17.3 months (95 % CI 10.4-25.1), respectively. The most common grade 3 or 4 toxicities were neutropenia (27 %), leukopenia (15 %), infection (10 %), and anemia (8 %).

CONCLUSION

The combination of biweekly paclitaxel and carboplatin was effective and well tolerated in elderly patients with advanced NSCLC.

FOXD1 expression is associated with poor prognosis in non-small cell lung cancer

AIM

Clinical microarray datasets were analyzed to search for new therapeutic targets and prognostic markers of non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Microarray datasets from 90 lung cancer specimens, were analyzed with focus on the FOXD1 gene. Levels of FOXD1 mRNA were assessed in lung cancer cell lines and these levels were correlated with survival.

RESULTS

FOXD1-knockdown led to suppression of cell proliferation. Moreover, patients with high FOXD1 expression survived for a significantly shorter time than those with low FOXD1 expression.

CONCLUSION

The expression status of FOXD1 is a novel prognostic factor and may lead to new treatment strategies for NSCLC.

Unexpected massive hemorrhage following the removal of a pleural drainage tube

We herein describe a case in which a massive hemorrhage unexpectedly occurred after the removal of a pleural drainage tube which had been in place for five days. One possible explanation for that event was the damage of the intercostal artery during tube insertion into the thoracic cavity. This is an extremely rare but severe complication. Therefore, the present report provides useful information for physicians who treat patients with respiratory diseases.

Methylation-induced downregulation of TFPI-2 causes TMPRSS4 overexpression and contributes to oncogenesis in a subset of non-small-cell lung carcinoma

We identified transmembrane protease, serine 4 (TMPRSS4) as a putative, druggable target by screening surgically resected samples from 90 Japanese non-small-cell lung cancer (NSCLC) patients using cDNA microarray. TMPRSS4 has two druggable domains and was upregulated in 94.5% of the lung cancer specimens. Interestingly, we found that TMPRSS4 expression was associated with tissue factor pathway inhibitor 2 (TFPI-2) expression in these clinical samples. In contrast to TMPRSS4, TFPI-2 expression was downregulated in NSCLC samples. The in vitro induction of TFPI-2 in lung cancer cell lines decreased the expression of TMPRSS4mRNA levels. Reporter assay showed that TFPI-2 inhibited transcription of TMPRSS4, although partially. Knockdown of TMPRSS4 reduced the proliferation rate in several lung cancer cell lines. When lung cancer cell lines were treated with 5-aza-2′-deoxycytidine or trichostatin A, their proliferation rate and TMPRSS4mRNA expression levels were also reduced through the upregulation of TFPI-2 by decreasing its methylation in vitro. The TFPI-2 methylation level in the low TMPRSS4 group appeared to be significantly low in NSCLC samples (P = 0.02). We found a novel molecular mechanism that TFPI-2 negatively regulates cell growth by inhibiting transcription of TMPRSS4. We suggest that TMPRSS4 is upregulated by silencing of TFPI-2 through aberrant DNA methylation and contributes to oncogenesis in NSCLC.

Abstract 5195: Claudin-1, a novel target of miR-375 in non-small cell lung cancer

MicroRNAs, the small and noncoding RNAs, regulate the translation of specific protein-coding genes. Accumulated evidence strongly suggests that microRNAs play important and complex roles in human cancers, including lung cancer. We previously reported that miR-375 expression was low in squamous cell carcinoma (SCC) and high in adenocarcinoma (AC) of lung cancer. The target gene of miR-375 in non-small cell lung cancer (NSCLC) has not been elucidated. The purpose of this study was to identify a target of miR-375 and clarify the function of miR-375 in NSCLC. Candidate genes of miR-375 targets were determined using the prediction databases and also previous findings about the different gene expression between SCC and AC. We focused on claudin-1 (CLDN1), which has four putative target sites of miR-375 in its 3′-untranslated region (UTR). CLDN1 was reported to express high in SCC and low in AC opposite to miR-375. We evaluated miR-375 and CLDN1 expression levels by quantitative polymerase chain reaction (qPCR) and Western blotting in 12 NSCLC cell lines. The effect of miR-375 overexpression upon the CLDN1 expression was evaluated in 5 NSCLC cell lines by transfecting miR-375 precursor. It showed that the expression of CLDN1 messenger RNA and protein were attenuated by miR-375 overexpression. Luciferase reporter assay was performed to confirm direct interaction between miR-375 and CLDN1. We cloned 3′-UTR of CLDN1 cDNA into the downstream of a luciferase reporter gene and co-transfected this vector into A549 cells with miR-375 precursor. MiR-375 overexpression resulted in a 3-fold repression of luciferase activity (p &lt; 0.001). To ascertain the clinical validity, we analyzed the relationship between miR-375 and CLDN1 expression in 63 clinical samples of NSCLC. There was a negative correlation between miR-375 and CLDN1 expression (r = -0.35, p = 0.005). In addition, we analyzed the correlation between miR-375 expression and overall survival in the same samples. High miR-375 expression correlated with poor survival in NSCLC (p = 0.043). To investigate the reason why high miR-375 expression lead to poor survival, wound healing assay was performed to evaluate the effect of miR-375 overexpression on the cell migration in SK-MES-1 cells. The cell migration was promoted by miR-375 overexpression, suggesting the high potential of invasion and metastasis in NSCLC expressing high level of miR375. In conclusion, we found that CLDN1 is a novel target of miR-375, and high miR-375 expression leads to poor survival in NSCLC.

Citation Format: Satoshi Yoda, Kenzo Soejima, Hiroyuki Yasuda, Takashi Sato, Daisuke Arai, Keiko Ohgino, Kota Ishioka, Tetsuo Tani, Ayano Oashi, Aoi Kuroda, Makoto Nishino, Masayoshi Miyawaki, Junko Hamamoto, Katsuhiko Naoki, Tomoko Betsuyaku. Claudin-1, a novel target of miR-375 in non-small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5195. doi:10.1158/1538-7445.AM2014-5195

Abstract 5652: Activation of FGF2-FGFR1 pathway in EGFR-mutant lung cancer cell line with long-term gefitinib exposure

Many of the patients with non-small cell lung cancer (NSCLC) with sensitive epidermal growth factor receptor (EGFR)-mutation who initially responded well to EGFR-tyrosine kinase inhibitors (TKIs) eventually relapse. In spite of many studies over the last few years to elucidate this mechanism of acquired resistance to EGFR-TKIs, approximately 30% of the mechanisms of acquired resistance are still unknown. Recently autocrine signaling of fibroblast growth factors (FGFs) and their receptors (FGFRs) has been demonstrated in NSCLC cell lines. And several studies suggest that the FGF-FGFR autocrine growth pathway could be an important mechanism for intrinsic resistance to EGFR-TKIs in NSCLC cell lines with wild-type EGFR. But until now, no report has clarified the role of FGF-FGFR pathway in acquired resistance to EGFR-TKIs in NSCLC cell lines with sensitive EGFR mutations. We have established a gefitinib-resistant cell line (PC9 GR), by serial exposure of gefitinib to PC9, an originally gefitinib-sensitive lung cancer cell line (PC9 na). We confirmed that these cell lines did not harbor two well-known EGFR-TKI resistance mechanisms, the second mutation in the EGFR gene itself, EGFR T790 and the amplification of the MET oncogene. We collected total RNA from both PC9 na and PC9 GR and examined mRNA expression profile, by using cDNA microarray analysis. We found the expressions of FGFR1 and FGF2 were increased in PC9 GR compared to in PC9 na. The growth of PC9 GR cells was inhibited either by PD173074 (inhibitors of FGFRs) or knocking down of FGFR1 or FGF2 by siRNA in combination with gefitinib. FACS analysis revealed that the combination treatment with PD173074 and gefitinib induced apoptosis more efficiently in PC9 GR cells compared to gefitinib alone. PC9 na cells and PC9 GR cells did not show any change in the proportion of apoptotic cells after treatment with PD173074 alone. To further investigate how FGF2-FGFR1 pathway affects resistance to gefitinib in these cell lines, the downstream targets of EGFR signaling including the MEK-ERK and PI3K-AKT pathways were examined. In PC9 na cells, the phosphorylation of EGFR, ERK, and AKT was efficiently inhibited by gefitinib alone. On the other hand, in PC9 GR cells, the phosphorylation of ERK and AKT was not efficiently inhibited by gefitinib alone. However, the inhibition of phosphorylation of ERK was completely and AKT was less efficiently rescued by gefitinib and PD173074 combination therapy. In conclusion, these data suggest the activation of FGF2-FGFR1 signaling pathway contributes to the gefitinib resistance in PC9 GR. FGF2-FGFR1 pathway will be a therapeutic target for a subset of NSCLC that acquires EGFR-TKI resistance.

Citation Format: Hideki Terai, Kenzo Soejima, Katsuhiko Naoki, Hiroyuki Yasuda, Ryosuke Satomi, Sohei Nakayama, Satoshi Yoda, Shinnosuke Ikemura, Takashi Sato, Kota Ishioka, Daisuke Arai, Keiko Ohgino, Tetsuo Tani, Aoi Kuroda, Junko Hamamoto, Tomoko Betsuyaku. Activation of FGF2-FGFR1 pathway in EGFR-mutant lung cancer cell line with long-term gefitinib exposure. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5652. doi:10.1158/1538-7445.AM2013-5652

Abstract 5257: FGF9 overexpression promotes tumorigenic potential of non-small cell lung cancer (NSCLC) cells, and is associated with poor prognosis in NSCLC patients

Background. Fibroblast growth factor 9 (FGF9) is a member of the FGF family, which modulates cell proliferation, differentiation and motility. Recent studies show that activation of FGF signals including FGF9 is associated with pathogenesis of several cancers. In lung cancer, some reports showed that FGF9 indirectly promoted the growth of lung adenocarcinoma and the intensity of FGF9 staining was positively correlated with the status of disease and the degree of lymph node metastasis in lung adenocarcinoma patients. However, the direct effect of FGF9 on the development and growth of lung cancer has not been clear.

Purpose. The purpose of this study is to clarify the role of FGF9 in NSCLC.

Method. First, we have performed in vitro analysis to clarify the role of FGF9 in NSCLC. FGF9 was introduced by retroviral infection to make stable cell lines. The cell lines which express no or low FGF9 were selected for the study, namely A549, PC9 and H1975. Overexpression of FGF9 in these cells was confirmed at mRNA and protein levels. Tumorigenic potential was evaluated by soft agar colony formation assay. The effect on proliferation of NSCLC cells was evaluated by MTS proliferation assay.

Next, patients survival analysis was also performed to evaluate the effect of FGF9 on the prognosis of NSCLC patients. NSCLC specimens were obtained from 91 patients who underwent surgical resection at Department of Thoracic Surgery, Keio University Hospital from 2001 through 2006 with written informed consent. We have performed cDNA microarray gene expression analysis. Patient survival data was evaluated by genes expression profile.

Results. Of the cells studied, A549 with FGF9 overexpression (A549-FGF9) cells significantly increased the anchorage independent colony formation ability compared with A549-empty cells. The numbers of the colonies were significantly higher in A549-FGF9, and the size of the colonies was bigger compared with A549-empty. For patient study, we found 10 out of 91 (11.0%) NSCLC patients overexpressed FGF9. We found FGF9 overexpression was associated with significantly worse prognosis (p=0.001). While none of other FGFs and FGFRs was associated with the prognosis of the patients. Three-year survival rate of FGF9-high patient group and FGF9-low patient group were 40% and 88% respectively. The rate of relapse was significantly higher in FGF9-high patients compared with FGF9-low patients, 60% vs 36.2% (p=0.016).

Conclusion. Our in vitro and clinical data indicate that FGF-9 may promote tumorigenic potential, and can be a prognostic indicator in NSCLC patients.

Citation Format: Kota Ishioka, Kenzo Soejima, Hiroyuki Yasuda, Keiko Ohgino, Satoshi Yoda, Takashi Sato, Junko Hamamoto, Daisuke Arai, Tetsuo Tani, Aoi Kuroda, Katsuhiko Naoki, Tomoko Betsuyaku. FGF9 overexpression promotes tumorigenic potential of non-small cell lung cancer (NSCLC) cells, and is associated with poor prognosis in NSCLC patients. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5257. doi:10.1158/1538-7445.AM2013-5257

Activation of the FGF2-FGFR1 autocrine pathway: a novel mechanism of acquired resistance to gefitinib in NSCLC

Patients with non-small cell lung cancer (NSCLC) that harbors epidermal growth factor receptor (EGFR) mutations initially respond to EGFR-tyrosine kinase inhibitors (TKI) but eventually experience relapse. Acquired resistance to EGFR-TKIs is strongly associated with patient mortality. Thus, elucidation of the mechanism of acquired resistance to EGFR-TKIs is of great importance. In this study, gefitinib-resistant cell line models were established by long-term exposure to gefitinib using the gefitinib-sensitive lung cancer cell lines, PC9 and HCC827. Expression analyses indicated that both FGFR1 and FGF2 were increased in PC9 gefitinib-resistant (PC9 GR) cells as compared with PC9 naïve (PC9 na) cells. Importantly, proliferation of gefitinib-resistant cells was dependent on the FGF2 -FGFR1 pathway. Mechanistically, inhibition of either FGF2 or FGFR1 by siRNA or FGFR inhibitor (PD173074) restored gefitinib sensitivity in PC9 GR cells. These data suggest that FGF2 -FGFR1 activation through an autocrine loop is a novel mechanism of acquired resistance to EGFR-TKIs.