EGFR and EML4-ALK Updated Therapies in Non-Small Cell Lung Cancer

EML4‑ALK fusion gene in non‑small cell lung cancer (Review)

Non-small cell lung cancer (NSCLC) is a malignant tumor with a high morbidity and mortality rate that is a threat to human health. With the development of molecular targeted research, breakthroughs have been made on the molecular mechanism of lung cancer. The echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene is one of the most important pathogenic driver genes of NSCLC discovered thus far. Four generations of targeted drugs for EML4-ALK have been developed, with patients benefiting significantly from these drugs. Therefore, EML4-ALK has become a research hotspot in NSCLC. The aim of the present study is to introduce the current research progress of EML4-ALK and its association with NSCLC.

Anticancer Effects of Amlodipine Alone or in Combination With Gefitinib in Non-Small Cell Lung Cancer

Amlodipine is a Ca²⁺ channel blocker commonly used to cardiovascular diseases such as hypertension and angina; however, its anticancer effects in lung cancer A549 cells remain unknown. In the present study, we explored the antitumor effects and molecular mechanisms underlying the action of amlodipine in non-small cell lung cancer (NSCLC) A549 cells in vitro and in vivo. We observed that amlodipine suppressed the proliferation of A549 lung cancer cells by arresting the tumor cell cycle. Mechanistically, our results revealed that amlodipine could attenuate the phosphoinositide 3 kinase (PI3K)/Akt and Raf/MEK/extracellular signal-regulated kinase (ERK) pathways through epidermal growth factor receptor (EGFR) and modulated cell cycle-related proteins such as cyclin D1, p-Rb, p27, and p21. Subsequently, amlodipine combined with gefitinib could synergistically inhibit cell proliferation by arresting the cell cycle. Moreover, amlodipine combined with gefitinib effectively attenuated the growth of A549 lung cancer xenografts when compared with monotherapy, affording an excellent therapeutic effect. Collectively, our results indicate that amlodipine alone or combined with the novel anticancer drug gefitinib might be a potential therapeutic strategy for NSCLC patients with wild-type EGFR.

Oncogene addiction and tumor mutational burden in non-small-cell lung cancer: Clinical significance and limitations

Lung cancer incidence has increased worldwide over the past decades, with non-small cell lung cancer (NSCLC) accounting for the vast majority (85%) of lung cancer specimens. It is estimated that lung cancer causes about 1.7 million global deaths per year worldwide. Multiple trials have been carried out, with the aim of finding new effective treatment options. Lately, special focus has been placed on immune checkpoint (PD1/PD-L1) inhibitors which impact the tumor immune microenvironment. Tumor mutational burden (TMB) has been found to predict response to immune checkpoint inhibitors. Conversely, recent studies have weakened the significance of TMB as a predictor of response to therapy and survival. In this review article, we discuss the significance of TMB, as well as possible limitations. Furthermore, we give a concise overview of mutations frequently found in NSCLC, and discuss the significance of oncogene addiction in lung cancer as an essential driver of tumorigenesis and tumor progression.

IGF2/IGF1R Signaling as a Therapeutic Target in MYB-Positive Adenoid Cystic Carcinomas and Other Fusion Gene-Driven Tumors

Chromosome rearrangements resulting in pathogenetically important gene fusions are a common feature of many cancers. They are often potent oncogenic drivers and have key functions in central cellular processes and pathways and encode transcription factors, transcriptional co-regulators, growth factor receptors, tyrosine kinases, and chromatin modifiers. In addition to being useful diagnostic biomarkers, they are also targets for development of new molecularly targeted therapies. Studies in recent decades have shown that several oncogenic gene fusions interact with the insulin-like growth factor (IGF) signaling pathway. For example, the MYB-NFIB fusion in adenoid cystic carcinoma is regulated by IGF1R through an autocrine loop, and IGF1R is a downstream target of the EWSR1-WT1 and PAX3-FKHR fusions in desmoplastic small round cell tumors and alveolar rhabdomyosarcoma, respectively. Here, we will discuss the mechanisms behind the interactions between oncogenic gene fusions and the IGF signaling pathway. We will also discuss the role of therapeutic inhibition of IGF1R in fusion gene driven malignancies.

Active fraction (HS7) from Taiwanofungus camphoratus inhibits AKT-mTOR, ERK and STAT3 pathways and induces CDK inhibitors in CL1-0 human lung cancer cells

Background

The non-small cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. In NSCLC, the oncogenic AKT-mTOR, ERK and STAT3 pathways are commonly dysregulated and have emerged as attractive targets for therapeutic developments. In a relatively limited subset of NSCLC, these pathways driven by mutant EGFR can be treated by the tyrosine kinase inhibitors (TKIs)-mediated targeted therapy. However, for the most NSCLC, more novel targeted agents are imperatively needed. Therefore, we investigated the inhibitory effects of the active fraction HS7 from Taiwanofungus camphoratus, a unique medicinal fungus in Taiwan, on these pathways in CL1-0 EGFR wild-type human NSCLC cells.

Methods

The active fraction HS7 was prepared by n-hexane extraction of T. camphoratus followed by silica gel chromatography. Its effects on the cell viabilities were determined by sulforhodamine B colorimetric assay. Flow cytometry was used to analyze cell-cycle regulation and apoptosis induction. The changes in cellular protein levels were examined by Western blot.

Results

The active fraction HS7 vigorously inhibits AKT-mTOR, ERK and STAT3 signaling pathways in CL1-0 cells. At dose of 25 μg/mL, these signaling pathways were almost completely inhibited by HS7, accompanied with induction of cyclin-dependent kinase inhibitors such as p15, p21 and p27. Accordingly, the AKT-mTOR downstream targets p-p70S6K and HIF-1α were also suppressed as well. At this dose, the cell proliferation was profoundly suppressed to 23.4% of control and apoptosis induction was observed.

Conclusions

The active fraction HS7 from n-hexane extract of T. camphoratus exerts multi-targeting activity on the suppression of AKT-mTOR, ERK and STAT3 pathways and induction of p15, p21 and p27 in EGFR wild-type NSCLC cells. This multi-targeting activity of HS7 suggests its potential as an alternative medicine for the treatment of EGFR TKIs resistant NSCLC.

Electronic supplementary material

The online version of this article (10.1186/s13020-017-0154-9) contains supplementary material, which is available to authorized users.

Detection of circulating tumor cells in patients with non-small cell lung cancer using a size-based platform

The detection of circulating tumor cells (CTCs) is limited by the rarity of these cells in the peripheral blood of patients with cancer. Understanding tumor biology may be useful in the development of novel therapeutic strategies for patients with lung cancer. The present study evaluated a novel size-based filtration platform for enriching CTCs from patients with lung cancer. Blood samples were obtained from 82 patients with lung cancer for CTC analysis. CTC enrichment by size-based filtration was performed on 5-ml blood samples. The collected cells were detected by immunofluorescence using monoclonal anti-human antibodies against protein tyrosine phosphatase, receptor type C (CD45) and epithelial cell adhesion molecule (EpCAM; an epithelial cell marker), as well as a DAPI nucleic acid stain. CTCs were detected in 57 patients (69.5%) using the size-based filtration platform. The mean CTC counts, defined as the number of cells with DAPI-positive, CD45-negative and EpCAM-positive staining, were 1.48±1.71 per 5 ml blood for the 66 stage I-III patients and 8.00±9.95 per 5 ml blood for the 16 stage IV patients. The presence of ≥1 CTCs per 5-ml blood sample was significantly associated with pathological stage (stage IV vs. stage I-III, P=0.009), but not with patient age or gender, tumor histology, tumor size or lymphovascular invasion. The mean CTC count of healthy donors was 0.25±0.55 per 5 ml blood. In summary, CTCs from the blood of patients with lung cancer were enriched using a size-based filtration platform and immunofluorescent staining with DAPI, CD45 and EpCAM. The CTC counts of patients with stage IV cancer were higher than those of patients with stages I-III cancer. These results suggest that this novel platform may be a useful tool for determining the prognosis of patients with lung cancer.