Surgery for NSCLC in the era of personalized medicine

Evaluation of Scoring Systems and Prognostic Factors in Patients With Spinal Metastases From Lung Cancer

STUDY DESIGN

A retrospective study of 180 patients with lung cancer spinal metastases, wherein prognostic score-predicted survival was compared with actual survival.

OBJECTIVE

To evaluate and compare the accuracy of prognostic scoring systems in lung cancer spinal metastases.

SUMMARY OF BACKGROUND DATA

The modified Tokuhashi, Tomita, modified Bauer, and Oswestry scores are currently used to guide decisions regarding operative treatment of patients with spinal metastases. The best system for predicting survival in patients with lung cancer spinal metastases remains undetermined. The high incidence of spinal metastases from lung cancer and improved survival of patients treated with systemic therapy warrants evaluation of these scoring systems in this particular context.

METHODS

Patients with lung cancer spinal metastases treated at our institution between May 2001 and August 2012 were studied. Fifty-one patients were treated surgically. The primary outcome measure was survival from the time of diagnosis. Scoring-predicted survival was compared with actual survival. Potential prognostic factors were investigated using Cox regression analyses. Predictive values of each scoring system for 3- and 6-month survival were measured via receiver operating characteristic (ROC) curves.

RESULTS

Histological subtype (P = 0.015), sex (P = 0.001), Karnofsky performance scale (P = 0.001), extent of neurological palsy (P = 0.002), and visceral metastases (P = 0.037) are significant predictors of survival. Besides the Oswestry spinal risk index, no significant differences were found between different prognostic subgroups within the individual scoring systems. Although the modified Bauer score was most accurate, all four scoring systems had areas under the ROC curve 0.5 or less.

CONCLUSION

Although better prognostic scores correlated with longer survival, all four scoring systems are inaccurate in prognosticating patients with lung cancer spinal metastases. Specific lung cancer histology appears prognostic and should be considered, especially given the increased survival of patients receiving new targeted therapies appropriate to their disease.

LEVEL OF EVIDENCE

3.

Molecular heterogeneity assessment by next-generation sequencing and response to gefitinib of EGFR mutant advanced lung adenocarcinoma

Cancer molecular heterogeneity might explain the variable response of EGFR mutant lung adenocarcinomas to tyrosine kinase inhibitors (TKIs). We assessed the mutational status of 22 cancer genes by next-generation sequencing (NGS) in poor, intermediate or good responders to first-line gefitinib. Clinical outcome was correlated with Additional Coexisting Mutations (ACMs) and the EGFR Proportion of Mutated Alleles (PMA). Thirteen ACMs were found in 10/17 patients: TP53 (n=6), KRAS (n=2), CTNNB1 (n=2), PIK3CA, SMAD4 and MET (n=1 each). TP53 mutations were exclusive of poor/intermediate responders (66.7% versus 0, p=0.009). Presence of ACMs significantly affected both PFS (median 3.0 versus 12.3 months, p=0.03) and survival (3.6 months versus not reached, p=0.03). TP53 mutation was the strongest negative modifier (median PFS 4.0 versus 14.0 months). Higher EGFR PMA was present in good versus poor/intermediate responders. Median PFS and survival were longer in patients with EGFR PMA ≥0.36 (12.0 versus 4.0 months, p=0.31; not reached versus 18.0 months, p=0.59). Patients with an EGFR PMA ≥0.36 and no ACMs fared significantly better (p=0.03), with a trend towards increased survival (p=0.06). Our exploratory data suggest that a quantitative (PMA) and qualitative (ACMs) molecular heterogeneity assessment using NGS might be useful for a better selection of patients.

Crosstalk with cancer-associated fibroblasts induces resistance of non-small cell lung cancer cells to epidermal growth factor receptor tyrosine kinase inhibition

Although lung cancers with activating mutations in the epidermal growth factor receptor (EGFR) are highly sensitive to selective EGFR tyrosine kinase inhibitors (TKIs), these tumors invariably develop acquired drug resistance. Host stromal cells have been found to have a considerable effect on the sensitivity of cancer cells to EGFR TKIs. Little is known, however, about the signaling mechanisms through which stromal cells contribute to the response to EGFR TKI in non-small cell lung cancer. This work examined the role of hedgehog signaling in cancer-associated fibroblast (CAF)-mediated resistance of lung cancer cells to the EGFR TKI erlotinib. PC9 cells, non-small cell lung cancer cells with EGFR-activating mutations, became resistant to the EGFR TKI erlotinib when cocultured in vitro with CAFs. Polymerase chain reaction and immunocytochemical assays showed that CAFs induced epithelial to mesenchymal transition phenotype in PC9 cells, with an associated change in the expression of epithelial to mesenchymal transition marker proteins including vimentin. Importantly, CAFs induce upregulation of the 7-transmembrane protein smoothened, the central signal transducer of hedgehog, suggesting that the hedgehog signaling pathway is active in CAF-mediated drug resistance. Indeed, downregulation of smoothened activity with the smoothened antagonist cyclopamine induces remodeling of the actin cytoskeleton independently of Gli-mediated transcriptional activity in PC9 cells. These findings indicate that crosstalk with CAFs plays a critical role in resistance of lung cancer to EGFR TKIs through induction of the epithelial to mesenchymal transition and may be an ideal therapeutic target in lung cancer.

Factors Associated with Life Expectancy in Patients with Metastatic Spine Disease from Adenocarcinoma of the Lung

Study Design Retrospective study. Objective Our objective was to identify preoperative prognostic factors associated with survival in patients with spinal metastasis from lung carcinoma. Methods A retrospective analysis of 26 patients diagnosed with lung carcinoma metastatic to the spinal column was performed to determine factors associated with survival. We used 3 months survival as the clinical cutoff for whether surgical intervention should be performed. We analyzed patients who survived less than 3 months compared with those who survived more than 3 months. Demographic, preoperative, operative, and postoperative factors including functional scores were collected for analysis. Results The median survival for all patients in our study was 3.5 months. We found a statistically significant difference between the group that survived less than 3 months and the group that survived greater than 3 months in terms of extrathoracic metastasis, visceral metastasis, and average postoperative modified Rankin score. Conclusion Determining which patients with lung cancer spinal metastases will benefit from surgical intervention is often dictated by the patient's predicted life expectancy. Factors associated with poorer prognosis include age, functional status, visceral metastases, and extrathoracic metastases. Although the prognosis for patients with lung cancer spinal metastases is poor, some patients may experience long-term benefit from surgical intervention.

Regulation of activating protein-4-associated metastases of non-small cell lung cancer cells by miR-144

Activating protein-4 (AP4) has been recently shown to regulate the cancer metastases in some cancers including non-small cell lung cancer (NSCLC). Specifically, AP4 regulates mTor/p21 and transforming growth factor β (TGFβ) receptor signaling pathway to increase an epithelial-mesenchymal transition process to augment cell invasiveness. Nevertheless, how AP4 is regulated in NSCLC has not been studied. Here, we showed that in the specimens from the NSCLC patients, the levels of miR-144 were significantly decreased and the levels of AP4 were significantly increased, compared to the paired non-tumor lung tissue. The levels of miR-144 and AP4 inversely correlated in patients' specimens. Bioinformatics analyses revealed that miR-144 targeted the 3'-UTR of AP4 mRNA to inhibit its translation, confirmed by luciferase-reporter assay. Moreover, miR-144 overexpression inhibited AP4-mediated cell invasiveness, while miR-144 depletion increased AP4-mediated cell invasiveness in NSCLC cells. Together, our data suggest that miR-144 suppression may be the cause of the increased levels of AP4, as well as the augmented cancer metastases, in NSCLC.

Phase II study of biomarker-guided neoadjuvant treatment strategy for IIIA-N2 non-small cell lung cancer based on epidermal growth factor receptor mutation status

Background

Neoadjuvant erlotinib and customized adjuvant therapy are appealing but controversial. The purpose of this study was to evaluate the role of biomarker-guided neoadjuvant treatment strategy in patients with IIIA-N2 non-small cell lung cancer (NSCLC) stratified by epidermal growth factor receptor (EGFR) mutation status.

Findings

Patients with resectable histologically documented stage IIIA-N2 NSCLC were assigned to a neoadjuvant erlotinib arm or a gemcitabine/carboplatin (GC) arm based on EGFR mutation status. The primary endpoint was response rate (RR). Secondary endpoints were progression-free survival (PFS) and overall survival (OS).

Twenty-four patients with IIIA-N2 NSCLC were enrolled in the trial from January 2008 until May 2011. The overall response rate was 41.7 % and the PFS and OS were 7.9 and 23.2 months, respectively, in overall population. The RR was 58.3 % (7/12) for the erlotinib arm with mutant EGFR and 25.0 % (3/12) for the GC arm with wild type EGFR (P = 0.18). Median PFS was 6.9 months versus 9.0 months, respectively (P = 0.071). Median OS was 14.5 months for the erlotinib arm and 28.1 months for the GC arm (P = 0.201). No unexpected toxicities were observed.

Conclusions

The primary endpoint was met and biomarker-guided neoadjuvant treatment strategy in patients with IIIA-N2 NSCLC is feasible. Erlotinib alone in neoadjuvant setting of EGFR mutant population showed an improved response but without survival benefits.

Trial registration

ClinicalTrials.gov NCT00600587 https://www.clinicaltrials.gov/ct2/show/NCT00600587?term=NCT00600587&rank=1

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-015-0151-3) contains supplementary material, which is available to authorized users.

A novel PI3K inhibitor iMDK suppresses non-small cell lung Cancer cooperatively with A MEK inhibitor

The PI3K-AKT pathway is expected to be a therapeutic target for non-small cell lung cancer (NSCLC) treatment. We previously reported that a novel PI3K inhibitor iMDK suppressed NSCLC cells in vitro and in vivo without harming normal cells and mice. Unexpectedly, iMDK activated the MAPK pathway, including ERK, in the NSCLC cells. Since iMDK did not eradicate such NSCLC cells completely, it is possible that the activated MAPK pathway confers resistance to the NSCLC cells against cell death induced by iMDK. In the present study, we assessed whether suppressing of iMDK-mediated activation of the MAPK pathway would enhance anti-tumorigenic activity of iMDK. PD0325901, a MAPK inhibitor, suppressed the MAPK pathway induced by iMDK and cooperatively inhibited cell viability and colony formation of NSCLC cells by inducing apoptosis in vitro. HUVEC tube formation, representing angiogenic processes in vitro, was also cooperatively inhibited by the combinatorial treatment of iMDK and PD0325901. The combinatorial treatment of iMDK with PD0325901 cooperatively suppressed tumor growth and tumor-associated angiogenesis in a lung cancer xenograft model in vivo. Here, we demonstrate a novel treatment strategy using iMDK and PD0325901 to eradicate NSCLC.

Trial Watch: Immunomodulatory monoclonal antibodies for oncological indications

Immunomodulatory monoclonal antibodies (mAbs) differ from their tumor-targeting counterparts because they exert therapeutic effects by directly interacting with soluble or (most often) cellular components of the immune system. Besides holding promise for the treatment of autoimmune and inflammatory disorders, immunomodulatory mAbs have recently been shown to constitute a potent therapeutic weapon against neoplastic conditions. One class of immunomodulatory mAbs operates by inhibiting safeguard systems that are frequently harnessed by cancer cells to establish immunological tolerance, the so-called "immune checkpoints." No less than 3 checkpoint-blocking mAbs have been approved worldwide for use in oncological indications, 2 of which during the past 12 months. These molecules not only mediate single-agent clinical activity in patients affected by specific neoplasms, but also significantly boost the efficacy of several anticancer chemo-, radio- or immunotherapies. Here, we summarize recent advances in the development of checkpoint-blocking mAbs, as well as of immunomodulatory mAbs with distinct mechanisms of action.

RET-targeting molecular stratified non-small-cell lung cancers

Recent advances in lung cancer genomics have successfully characterized therapeutic targets of lung cancer. RET fusion gene products are among the newest target molecules for lung adenocarcinoma. Preclinical findings and preliminary reports regarding potential tumor control by RET-targeting multi-kinase inhibitors encourage further clinical trials. The infrequent prevalence of RET fusion gene-positive cases may be a major obstacle hindering the development of RET-targeted therapy. Thus, it is necessary to recruit appropriate participants for trials to develop an efficient RET fusion gene detection system to achieve targeted therapy for lung adenocarcinomas stratified by this molecular target.

Cyclooxygenase-2 expression is a prognostic biomarker for non-small cell lung cancer patients treated with adjuvant platinum-based chemotherapy

Background

Adjuvant chemotherapy after the resection of stage IB-IIIA non-small cell lung cancer (NSCLC) is now the standard of care based on large-scale phase III trials and a meta-analysis. However, chemotherapy has plateaued in terms of its efficacy, and the search for treatment prediction biomarkers is imperative for the further identification of treatable subgroups. Therefore, we investigated the significance of cyclooxygenase-2 (Cox-2) expression and the applicability of a Cox-2 inhibitor in patients who had received adjuvant chemotherapy.

Methods

We conducted a retrospective review of data from 97 patients who had received adjuvant chemotherapy. The adjuvant chemotherapy consisted of an oral tegafur agent (OT) or platinum-based chemotherapy (PB). The criteria for regimen selection were based on a discussion among the cancer board and enrollment in a clinical trial. Immunohistochemical staining (IHC) for Cox-2 was performed, and the correlation between Cox-2 expression and disease-free survival (DFS) was evaluated.

Results

IHC showed that 56 cases (57.7%) were positive for Cox-2. The rate of Cox-2 expression was similar for the PB and OT groups. Among the patients who received PB, the DFS of the patients with Cox-2 expression was significantly poorer than that of the patients without Cox-2 expression (P = 0.017), but there was no significant difference among the patients who received OT (P = 0.617). In a multivariate analysis, Cox-2 expression and lymph node metastasis were independent predictors of DFS among patients who received PB.

Conclusions

Cox-2 expression was a powerful predictor of DFS among patients who received PB as an adjuvant chemotherapy. Further study investigating the use of a Cox-2 inhibitor for adjuvant chemotherapy is needed.

RBPJ inhibition impairs the growth of lung cancer

The exact effects of the modulation of Notch signaling pathway on cell growth have been shown to depend on tumor cell type. Recombination signal-binding protein Jκ (RBPJ) is a key transcription factor downstream of receptor activation in Notch signaling pathway. Here, we evaluated the effects of RBPJ inhibition on the growth of lung cancer cells. We found that a short hairpin interfering RNA (shRNA) for RBPJ efficiently inhibited RBPJ expression in lung cancer cells, resulting in a significant decrease in the cell growth. Further analyses showed that RBPJ inhibition altered the levels of its downstream targets, including p21, p27, CDK2, Hes1, Bcl-2, and SKP2, to prevent the cells from growing. Our data thus suggest that shRNA intervention of RBPJ expression could be a promising therapeutic approach for treating human lung cancer.

Podophyllotoxin acetate enhances γ-ionizing radiation-induced apoptotic cell death by stimulating the ROS/p38/caspase pathway

To develop a new radiosensitizer against non-small cell lung cancer cells, we screened a natural product library for growth-inhibitory compounds. PA was found to be cytotoxic toward NCI-H460 cells, and its IC₅₀ value was determined. The radiosensitizer effects of PA were tested at its IC₅₀ value in clonogenic and cell-counting assays. The intracellular mechanism underlying this effect was determined by immunoblotting and by measuring propidium iodide uptake and ROS generation. The radiosensitizer activity of PA in vivo was tested in nude mice by treating with PA and IR, and measuring tumor volume and assessing apoptosis. PA, tested at its experimentally determined IC₅₀ value (12 nM), enhanced IR-induced death of NCI-H460 cells by increasing apoptosis, yielding a mean calculated dose-enhancement ratio of 1.67. Combination with PA and IR also increased the production of ROS, which subsequently induced phosphorylation of p38, suppressed phosphorylation of ERK, and activated caspase-3, -8, and -9. Notably, inhibition of ROS production prevented p38 phosphorylation, and inhibition of ROS production or p38 activation blocked caspase activation and apoptosis. In a xenograft assay, combination with PA and IR delayed tumor growth by 11.4 days compared with controls, yielding an enhancement factor of 1.48. Collectively, these results indicate that PA functions as a radiosensitizer by enhancing apoptosis through activation of a ROS/p38/caspase pathway and suppression of ERK.

Activation of FGF receptor signaling promotes invasion of non-small-cell lung cancer

The molecular regulation of metastasis of non-small-cell lung cancer (NSCLC) remains not completely defined. Here we showed significant higher MMP26 in the resected NSCLC than adjacent healthy tissue from the patients. Moreover, a strong correlation between MMP26 and the phosphorylated fibroblast growth factor receptor 1 (FGFR1) was detected. To examine the causal relationship between activated FGFR signaling and MMP26, we studied a human NSCLC cell line, A549. We found that FGF1-induced FGFR1 phosphorylation in A549 cells activated MMP26, resulting in an increase in cancer invasiveness. Inhibition of FGFR1 phosphorylation abolished FGF1-stimulated MMP26 activation, suggesting that activation of FGFR signaling pathway in NSCLC promotes cancer metastasis through MMP26. To define the signal transduction cascades downstream of FGFR1 activation for MMP26 activation, we used specific inhibitors for PI3K, ERK/MAPK, and JNK, respectively, to the FGF1-stimulated A549 cells. We found that only inhibition of JNK significantly decreased the activation of MMP26 in response to FGF1 stimulation, suggesting that activation of FGFR1 signaling may activate JNK to activate MMP26 in NSCLC. Our study thus highlights FGFR signaling pathway and MMP26 as novel therapeutic targets for NSCLC therapy.

Long-term outcome of surgical resection for residual or regrown advanced non-small cell lung carcinomas following EGFR-TKI treatment: report of four cases

We report the long-term outcome of 4 patients who underwent pulmonary resection for residual or regrown primary lesion of non-small cell lung cancer (NSCLC) treated with a epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) gefitinib. Two patients underwent surgical resection for localized regrown primary lesion after gefitinib for stage IV disease. The remaining two patients underwent surgery for localized residual primary lesion that was downstaged to N0 after gefitinib for initially inoperable cN2 (stage IIIA) disease. Three patients developed recurrence with a median progression-free period of 1.2 years (0.2-2.2), but they survived more than 5 years postoperatively with good local control. One patient who initially had cN2 disease is alive without recurrence after 4 years with continued postoperative gefitinib. Although our series is small, the relatively favorable long-term survival indicates the need for further investigation of the role of surgery during molecular-targeted therapy for advanced NSCLC.

Recent evidence, advances, and current practices in surgical treatment of lung cancer

In the last 10-15 years, strategies and modalities of lung cancer treatment have changed dramatically. Meanwhile, the treatment objectives, the lung cancers themselves, have also changed, probably owing to early detection by computed tomography and aging of the population. In particular, the proportions of smaller lung cancers, lung adenocarcinomas with ground-glass opacity, and lung cancers in older patients are increasing. Along with these changes, surgeons have innovated and evaluated novel procedures for pulmonary resection. These include the application of minimally invasive surgical techniques, such as video-assisted thoracoscopic surgery (VATS) and robotic surgery, and sub-lobar resection, such as wedge resection and segmentectomy, for small peripheral lung cancers. Currently, VATS has gained wide acceptance and several institutions in Japan have started using robotic surgery for lung cancers. Two important clinical trials of sub-lobar resection for small peripheral lung cancers are now underway in Japan. In addition, surgery itself is of growing importance in lung cancer treatment. In particular, recent evidence supports the use of surgery in strictly selected patients with locally advanced disease, lung cancers with N2 lymph node metastases, small cell lung cancers, recurrent oligo-metastasis after pulmonary resection, or relapsed tumors after drug treatment. Surgical treatment also provides abundant tumor samples for molecular analysis, which can be used for drug selection in the adjuvant setting or after disease relapse. In the era of personalized treatment, surgery is still one of the most important treatment modalities to combat lung cancer.

Vascular endothelial growth factor B coordinates metastasis of non-small cell lung cancer

Neovascularization is critical for the invasion and metastasis of non-small cell lung cancer (NSCLC). However, the molecular mechanism underlying the control of neovascularization of NSCLC is not completely understood. Both vascular endothelial growth factor B (VEGF-B) and matrix metalloproteinases 9 (MMP9) play essential roles in neovascularization of NSCLC. Here, we examined whether VEGF-B and MMP9 may affect each other to coordinate the neovascularization process in NSCLC. We found strong positive correlation of VEGF-B and MMP9 levels in the NSCLC from the patients. Moreover, patients that had NSCLC with metastasis had significantly higher levels of VEGF-B and MMP9 in the primary cancer. Using a human NSCLC line A549, we found that overexpression of VEGF-B increased expression of MMP9, while inhibition of VEGF-B decreased expression of MMP9. On the other hand, overexpression of MMP9 increased expression of VEGF-B, while inhibition of MMP9 decreased expression of VEGF-B. These data suggest that expression of VEGF-B and MMP9 may activate each other to enhance neovascularization. We then analyzed the underlying mechanism. Application of a specific ERK/MAPK inhibitor but not a PI3K/Akt inhibitor to VEGF-B-overexpressing A549 cells substantially abolished the effect of VEGF-B on MMP9 activation, while application of a specific PI3K/Akt inhibitor but not an ERK/MAPK inhibitor to MMP9-overexpressing A549 cells substantially abolished the effect of MMP9 on VEGF-B activation, suggesting that VEGF-B may activate MMP9 via ERK/MAPK signaling pathway, while MMP9 may activate VEGF-B via PI3K/Akt signaling pathway. Thus, our data highlight a coordinating relationship between VEGF-B and MMP9 in the regulation of neovascularization in NSCLC.

Crosstalk of AP4 and TGFβ receptor signaling in NSCLC

The molecular regulation of growth of non-small cell lung cancer (NSCLC) has not been fully clarified. In NSCLC, we detected significantly higher levels of activating protein-4 (AP4), significantly lower levels of p21, and significantly lower levels of phosphorylated SMAD2 as an indicator of activated transforming growth factor β (TGFβ) receptor signaling, compared to the adjacent normal lung tissue. Moreover, a strong negative correlation was detected between AP4 and p21 levels. Since p21 is a potent cell-cycle inhibitor, we were thus promoted to examine the relationships among AP4, TGFβ receptor signaling, and cell growth in NSCLC. Using a human NSCLC cell line HepG2 cells, we found that activation of TGFβ receptor signaling increased p21 levels through phosphorylation of SMAD2. Moreover, AP4 inhibited phosphorylation of SMAD2 to contradict the effect of activated TGFβ receptor signaling on cell growth inhibition in NSCLC. Furthermore, binding of TGFβ1 to its receptor also directly increased AP4 transcription, which appeared to negatively control the levels of activated TGFβ receptor signaling. Taken together, our results suggest that AP4 may inhibit the phosphorylation of SMAD2, which is induced by receptor binding with TGFβ1, to abolish the inhibitory effect of activated TGFβ receptor signaling on cell growth in NSCLC. Our study thus highlights AP4 as a novel therapeutic target for NSCLC.

Recurrence after surgery in patients with NSCLC

Surgery remains the only potentially curative modality for early-stage non-small cell lung cancer (NSCLC) patients and tissue availability is made possible. However, a proportion of lung cancer patients develop recurrence, even after curative resection. This review discusses the superiority of surgery, the reasons for recurrence, the timing and pattern of recurrence, the identification of factors related to recurrence, current provisions for treatment and perspectives about surgery for patients with NSCLC.

A decrease in the size of ground glass nodules may indicate the optimal timing for curative surgery

OBJECTIVES

Although ground glass nodules (GGNs) are generally considered to grow slowly to a large size, their natural progression remains unclear, and a decrease in tumor size has been reported in a few previous studies. The study aimed to retrospectively review the radiologic and pathological characteristics of resected ground glass nodules (GGNs) followed with chest computed tomography (CT) for at least a year before surgery to clarify the natural progression of GGNs.

PATIENTS AND METHODS

The chest CT cans and clinical charts of 32 GGNs in 31 patients who underwent pulmonary resection between January 2006 and March 2013 were retrospectively reviewed. The definitions of pure GGNs and part-solid nodules were based on the tumor shadow disappearance rate. The tumor size was measured twice, and the mean size was used for evaluation.

RESULTS

The mean GGN size before surgery was 15.2 mm, and the median follow-up period before surgery was 21 months. In the follow-up period, 15 (58%) of 26 pure GGNs at the initial CT remained pure GGNs at the last CT. However, a solid component appeared in the remaining 11 tumors (42%) of the 26 initial pure GGNs. Furthermore, 1 GGN of the 15 GGNs that remained pure and 10 of the 11 GGNs with solid component also showed a size decrease. In addition, 6 part-solid nodules were observed at the initial CT. Of these, 3 showed a decrease in size during follow-up. Overall, 47% of the GGNs showed a size reduction on follow-up chest CT.

CONCLUSIONS

A size reduction was observed in nearly half of the GGNs and suggested the progression to an invasive adenocarcinoma. When a mild collapse of the GGNs is observed, a careful follow-up is necessary to identify a solid component. Tumor size decreases may represent the optimal timing of pulmonary resection for curative treatment.

MicroRNA-133a suppresses multiple oncogenic membrane receptors and cell invasion in non-small cell lung carcinoma

Non-small cell lung cancers (NSCLCs) cause high mortality worldwide, and the cancer progression can be activated by several genetic events causing receptor dysregulation, including mutation or amplification. MicroRNAs are a group of small non-coding RNA molecules that function in gene silencing and have emerged as the fine-tuning regulators during cancer progression. MiR-133a is known as a key regulator in skeletal and cardiac myogenesis, and it acts as a tumor suppressor in various cancers. This study demonstrates that miR-133a expression negatively correlates with cell invasiveness in both transformed normal bronchial epithelial cells and lung cancer cell lines. The oncogenic receptors in lung cancer cells, including insulin-like growth factor 1 receptor (IGF-1R), TGF-beta receptor type-1 (TGFBR1), and epidermal growth factor receptor (EGFR), are direct targets of miR-133a. MiR-133a can inhibit cell invasiveness and cell growth through suppressing the expressions of IGF-1R, TGFBR1 and EGFR, which then influences the downstream signaling in lung cancer cell lines. The cell invasive ability is suppressed in IGF-1R- and TGFBR1-repressed cells and this phenomenon is mediated through AKT signaling in highly invasive cell lines. In addition, by using the in vivo animal model, we find that ectopically-expressing miR-133a dramatically suppresses the metastatic ability of lung cancer cells. Accordingly, patients with NSCLCs who have higher expression levels of miR-133a have longer survival rates compared with those who have lower miR-133a expression levels. In summary, we identified the tumor suppressor role of miR-133a in lung cancer outcome prognosis, and we demonstrated that it targets several membrane receptors, which generally produce an activating signaling network during the progression of lung cancer.

The combination of strong expression of ZNF143 and high MIB-1 labelling index independently predicts shorter disease-specific survival in lung adenocarcinoma

Background:

The transcription factor, zinc finger protein 143 (ZNF143), positively regulates many cell-cycle-related genes. The ZNF143 would show high expression of multiple solid tumours related closely to cancer cell growth, similar to the widely accepted Ki67 (MIB-1) protein, but the underlying mechanisms for ZNF143 remain unclear. We investigated the association of ZNF143 expression with clinicopathological features and prognoses of patients with lung adenocarcinoma.

Methods:

Expressions of ZNF143 and MIB-1 were immunohistochemically analysed in 183 paraffin-embedded tumour samples of patients with lung adenocarcinoma. The ZNF143 expression was considered to be strong when >30% of the cancer cells demonstrated positive staining.

Results:

Strong ZNF143+ expression showed a significantly close relationship to pathologically moderate to poor differentiation and highly invasive characteristics. The ZNF143 positivity potentially induced cell growth of lung adenocarcinoma, correlated significantly with high MIB-1 labelling index (⩾10%). Univariate and multivariate analyses demonstrated that both strong ZNF143+ and the high MIB-1 index group have only and significantly worse survival rates.

Conclusions:

The combination of strong ZNF143 expression and high MIB-1 index potentially predicts high proliferating activity and poor prognosis in patients with lung adenocarcinoma, and may offer a therapeutic target against ZNF143.

MMP9 activation triggered by epidermal growth factor induced FoxO1 nuclear exclusion in non-small cell lung cancer

The molecular mechanism underlying activation of matrix metallopeptidase 9 (MMP9) in non-small cell lung cancer (NSCLC) cells, which controls cancer invasiveness and metastasis, remains elusive. Here, we reported a strong correlation of epidermal growth factor receptor (EGFR) and MMP9 levels in NSCLC patients. Thus, we used a human NSCLC line, A549, to examine whether there is a causal link between EGFR and MMP9 activation. We found that EGF-induced activation of EGFR in A549 cells activated MMP9, resulting in an increase in cancer invasiveness. An EGFR inhibitor efficiently blocked this EGF-induced activation of MMP9 and, consequently, increased cancer invasiveness. Moreover, an inhibitor for phosphatidylinositol 3-kinase (PI3K)/Akt, but not an inhibitor for mitogen-activated protein kinase, or an inhibitor for Jun N-terminal kinase, significantly inhibited the epidermal growth factor (EGF)-induced activation of MMP9, suggesting that PI3K/Akt signaling cascades may be responsible for EGF-activated MMP9. We further dissected the pathway and found that nuclear exclusion of a major Akt downstream target, FoxO1, occurred by EGF-induced Akt activation, which could be inhibited by either EGFR inhibitor or by PI3K/Akt inhibitor. In a loss of function, expression of a constitutive nuclear form of FoxO1 significantly inhibited MMP9 activation induced by EGF. Taken together, these findings suggest that EGF/EGFR signaling activates downstream PI3K/Akt to induce FoxO1 nuclear exclusion, which activates MMP9 to promote NSCLC invasiveness. Thus, Akt and FoxO1, in addition to the well-known EGFR, appear to be promising therapeutic targets for preventing the metastasis of NSCLC.

Establishment and characterization of a lung cancer cell line, SMC-L001, from a lung adenocarcinoma

Lung cancer cell lines are a valuable tool for elucidating lung tumorigenesis and developing novel therapies. However, the majority of cell lines currently available were established from tumors in patients of Caucasian origin, limiting our ability to investigate how cancers in patients of different ethnicities differ from one another in terms of tumor biology and drug responses. In this study, we established a human non-small cell lung carcinoma cell line, SMC-L001, and characterized its genome and tumorigenic potential. SMC-L001 cells were isolated from a Korean lung adenocarcinoma patient (male, pStage IIb) and were propagated in culture. SMC-L001 cells were adherent. DNA fingerprinting analysis indicated that the SMC-L001 cell line originated from parental tumor tissue. Comparison of the genomic profile of the SMC-L001 cell line and the original tumor revealed an identical profile with 739 mutations in 46 cancer-related genes, including mutations in TP53 and KRAS. Furthermore, SMC-L001 cells were highly tumorigenic, as evidenced by the induction of solid tumors in immunodeficient mice. In summary, we established a new lung cancer cell line with point mutations in TP53 and KRAS from a Korean lung adenocarcinoma patient that will be useful for investigating ethnic differences in lung cancer biology and drug response.

EGFR T790M mutation as a possible target for immunotherapy; identification of HLA-A*0201-restricted T cell epitopes derived from the EGFR T790M mutation

Treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, has achieved high clinical response rates in patients with non–small cell lung cancers (NSCLCs). However, over time, most tumors develop acquired resistance to EGFR-TKIs, which is associated with the secondary EGFR T790M resistance mutation in about half the cases. Currently there are no effective treatment options for patients with this resistance mutation. Here we identified two novel HLA-A*0201 (A2)-restricted T cell epitopes containing the mutated methionine residue of the EGFR T790M mutation, T790M-5 (MQLMPFGCLL) and T790M-7 (LIMQLMPFGCL), as potential targets for EGFR-TKI-resistant patients. When peripheral blood cells were repeatedly stimulated in vitro with these two peptides and assessed by antigen-specific IFN-γ secretion, T cell lines responsive to T790M-5 and T790M-7 were established in 5 of 6 (83%) and 3 of 6 (50%) healthy donors, respectively. Additionally, the T790M-5- and T790M-7-specific T cell lines displayed an MHC class I-restricted reactivity against NSCLC cell lines expressing both HLA-A2 and the T790M mutation. Interestingly, the NSCLC patients with antigen-specific T cell responses to these epitopes showed a significantly less frequency of EGFR-T790M mutation than those without them [1 of 7 (14%) vs 9 of 15 (60%); chi-squared test, p  =  0.0449], indicating the negative correlation between the immune responses to the EGFR-T790M-derived epitopes and the presence of EGFR-T790M mutation in NSCLC patients. This finding could possibly be explained by the hypothesis that immune responses to the mutated neo-antigens derived from T790M might prevent the emergence of tumor cell variants with the T790M resistance mutation in NSCLC patients during EGFR-TKI treatment. Together, our results suggest that the identified T cell epitopes might provide a novel immunotherapeutic approach for prevention and/or treatment of EGFR-TKI resistance with the secondary EGFR T790M resistance mutation in NSCLC patients.

Development of personalized treatments in lung cancer: focusing on the EGFR mutations and beyond

Lung cancers with epidermal growth factor receptor (EGFR) gene mutation account for ∼40% of adenocarcinoma in East Asians and ∼15% of that in Caucasians, which makes them one of the most common molecularly defined lung cancer subsets. The role of EGFR mutation as a strong predictive biomarker of response to EGFR-tyrosine kinase inhibitors (TKIs) was finally confirmed by the biomarker analysis of Iressa Pan-Asian Study (IPASS). Since the 2004 discovery of EGFR mutation in lung cancer, the EGFR mutation and EGFR-TKI treatment have been widely studied. These include characteristics of lung cancers with EGFR mutations; clinical efficacies and adverse effects of EGFR-TKIs in patients with EGFR-mutated lung cancers; development of novel EGFR-TKIs that may prolong progression-free survival of these patients or overcome resistance to first-generation EGFR-TKIs (gefitinib and erlotinib); optimal treatment schedules for EGFR-TKIs to delay emergence of resistance; molecular mechanisms of acquired resistance to EGFR-TKIs; treatment strategies after patients acquire resistance to EGFR-TKIs; and predictive biomarkers for EGFR-TKIs among patients with EGFR-mutated lung cancers. Some of these results are widely accepted, while others are apparent only in cell line models, preclinical animal models, or retrospective analyses (and sometimes conflict with each other). In this review, we summarize accumulated reports from the past decade, especially focusing on unanswered but important clinical questions in treating patients with EGFR-mutated lung cancers.