Shawn J. Rice

MiR-365 regulates lung cancer and developmental gene thyroid transcription factor 1

Thyroid transcription factor 1 (TTF-1 or NKX2-1) is an essential fetal lung developmental factor, which can be recurrently activated by gene amplification in adult lung cancer. We have discovered the first microRNA (i.e., miR-365) that directly regulates TTF-1 by interacting with its 3’-untranslated region. By gene expression profiling, we identified other putative targets of miR-365 and miR-365*. In line with the microRNA/target relationship, the expression patterns of miR-365 and TTF-1 were in an inverse relationship in human lung cancer. Exploration of human lung cancer genomics data uncovered that TTF-1 gene amplification was significantly associated with DNA copy number loss at one of the two genomic loci encoding the precursor RNA of mature miR-365 (i.e., mir-365-1). This implies the existence of genetic selection pressure to lose the repressive miR-365 that would otherwise suppress amplified TTF-1. We detected a signaling loop between transforming growth factor beta (TGFb) and miR-365 and this loop reinforced suppression of TTF-1 via miR-365. Mir-365 also targeted an epithelial mesenchymal transition (EMT)-promoting gene HMGA2. In summary, these data connect the lung transcriptional program to the microRNA network.

Occludin Is a Direct Target of Thyroid Transcription Factor-1 (TTF-1/NKX2–1)

Background: TTF-1, an amplified lung oncogene, also suppresses lung cancer metastasis, whereas the occludin phenotype in lung carcinomas is poorly understood. Results: TTF-1 transactivates occludin and occludin expression, reversing metastatic characteristics of lung cancer cells. Conclusion: Transcriptional regulation of occludin by TTF-1 negates metastatic properties of lung carcinoma cells. Significance: This study describes a novel extension of the multipronged anti-metastatic activity of TTF-1. The thyroid transcription factor 1 gene (TTF-1 or NKX2–1) is essential to lung development; however, it is also a critical factor in lung cancer. TTF-1 is amplified in lung cancers, suggesting that it is a gain-of-function lung oncogene. Conversely, TTF-1 counters epithelial to mesenchymal transition in cell-based studies and inhibits progression of primary lung adenocarcinomas to metastases in an animal model of lung adenocarcinomas. The unifying theory regarding TTF-1 is that it exhibits both pro-oncogenic and anti-metastatic function depending on the cellular context. Occludin is the first discovered constituent of the epithelial tight junction; in recent years, a functional role of occludin as a tumor suppressor has begun to emerge. Here, we demonstrate that TTF-1 transactivated the expression of the epithelial tight junction molecules occludin (OCLN) and claudin-1 (CLDN1). We show that transcriptional activation occurred through a direct interaction of TTF-1 with the OCLN and CLDN1 promoters. Furthermore, in cells that lack TTF-1, exogenous TTF-1 expression dampened the inhibitory effect of TGF-β on occludin and claudin-1 content. Using cells derived from a genetically engineered mouse model of lung adenocarcinomas, we observed that silenced TTF-1 expression down-regulated occludin, which we supported with additional siRNA experiments. Finally, TTF-1 knockdown conferred human lung cancer cells resistance to anoikis, and expression of occludin restored cellular sensitivity to anoikis. Overexpression of occludin impeded migration and induced anoikis in lung carcinoma cells. Collectively, these data suggest that TTF-1 transcriptionally regulates occludin, which represents another avenue of TTF-1-mediated metastasis suppression.

MicroRNA-33a Mediates the Regulation of High Mobility Group AT-Hook 2 Gene (HMGA2) by Thyroid Transcription Factor 1 (TTF-1/NKX2–1)

Background: TTF-1 inhibits lung cancer progression via HMGA2 down-regulation. Results: TTF-1 up-regulates miR-33a, which in turn directly represses HMGA2. Conclusion: The signaling axis of TTF-1 to HMGA2, important in controlling lung cancer metastasis, is mediated by miR-33a. Significance: This study explains the mechanism of HMGA2 suppression by TTF-1. In lung cancers, TTF-1 displays seemingly paradoxical activities. Although TTF-1 is amplified in primary human lung cancers, it inhibits primary lung tumors from metastasizing in a mouse model system. It was reported that the oncogenic proepithelial mesenchymal transition (EMT) high mobility group AT-hook 2 gene (HMGA2) mediates the antimetastatic function of TTF-1. To gain mechanistic insight into the metastasis-critical signaling axis of TTF-1 to HMGA2, we used both reverse and forward strategies and discovered that microRNA-33a (miR-33a) is under direct positive regulation of TTF-1. By chromatin immunoprecipitation, we determined that TTF-1 binds to the promoter of SREBF2, the host gene of miR-33a. The 3′-untranslated region (UTR) of HMGA2 contains three predicted binding sites of miR-33a. We showed that the first two highly conserved sites are conducive to HMGA2 repression by miR-33a, establishing HMGA2 as a genuine target of miR-33a. Functional studies revealed that enforced expression of miR-33a inhibits the motility of lung cancer cells, and this inhibition can be rescued by overexpression of the form of HMGA2 without the 3′-UTR, suggesting that TTF-1 keeps the prometastasis gene HMGA2 in check via up-regulating miR-33a. This study reports the first miRNAs directly regulated by TTF-1 and clarifies how TTF-1 controls HMGA2 expression. Moreover, the documented importance of SREBF2 and miR-33a in regulating cholesterol metabolism suggests that TTF-1 may be a modulator of cholesterol homeostasis in the lung. Future studies will be dedicated to understanding how miRNAs influence the oncogenic activity of TTF-1 and the role of TTF-1 in cholesterol metabolism.

Trametinib with or without Vemurafenib in BRAF Mutated Non-Small Cell Lung Cancer

V-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF) mutated lung cancer is relatively aggressive and is resistant to currently available therapies. In a recent phase II study for patients with BRAF-V600E non-small cell lung cancer (NSCLC), BRAF V600E inhibitor demonstrated evidence of activity, but 30% of this selected group progressed while on treatment, suggesting a need for developing alternative strategies. We tested two different options to enhance the efficacy of vemurafenib (BRAF V600E inhibitor) in BRAF mutated NSCLC. The first option was the addition of erlotinib to vemurafenib to see whether the combination provided synergy. The second was to induce MEK inhibition (downstream of RAF) with trametinib (MEK inhibitor). We found that the combination of vemurafenib and erlotinib was not synergistic to the inhibition of p-ERK signaling in BRAF-V600E cells. Vemurafenib caused significant apoptosis, G1 arrest and upregulation of BIM in BRAF-V600 cells. Trametinib was effective as a single agent in BRAF mutated cells, either V600E or non-V600E. Finally, the combination of vemurafenib and trametinib caused a small but significant increase in apoptosis as well as a significant upregulation of BIM when compared to either single agent. Thus, hinting at the possibility of utilizing a combinational approach for the management of this group of patients. Importantly, trametinib alone caused upregulation of p-AKT in BRAF non-V600 mutated cells, while this effect was nullified with the combination. This finding suggests that, the combination of a MEK inhibitor with a BRAF inhibitor will be more efficacious in the clinical setting for patients with BRAF mutated NSCLC.

Rapid magnetic isolation of extracellular vesicles via lipid-based nanoprobes

Extracellular vesicles (EVs) can mediate intercellular communication by transferring cargo proteins and nucleic acids between cells. The pathophysiological roles and clinical value of EVs are under intense investigation, yet most studies are limited by technical challenges in the isolation of nanoscale EVs (nEVs). Here, we report a lipid nanoprobe that enables spontaneous labelling and magnetic enrichment of nEVs in 15 minutes, with isolation efficiency and cargo composition similar to what can be achieved by the much slower and bulkier method of ultracentrifugation. We also show that the lipid nanoprobes, which allow for downstream analyses of nucleic acids and proteins, enabled the identification of EGFR and KRAS mutations following nEV isolation from blood plasma from non-small-cell lung-cancer patients. The efficiency and versatility of the lipid nanoprobe opens up opportunities in point-of-care cancer diagnostics.

Expression of PD-1 on CD4+ T cells in peripheral blood associates with poor clinical outcome in non-small cell lung cancer.

Recent success of using agents inhibiting the major immune check point, programmed cell death-1 (PD-1) pathway, offers a great promise for effective cancer therapy. Two blocking antibodies for PD-1, nivolumab and pembrolizumab have recently been approved for treating advanced recurrent non-small cell lung cancer (NSCLC). Activation of PD-1 on T cells and PD-L1 on tumor cells or antigen presenting cells leads to T cell exhaustion and ultimately tumor growth. In this study, we performed flow cytometry analysis of peripheral blood samples collected from patients with advanced NSCLC at initial diagnosis. We report that surface expression of PD-1 on CD4+ T cells has a prognostic value in NSCLC patients, as high expression of PD-1 is associated with a shorter progression-free survival and overall survival. Importantly, we also found that high PD-1 expression on peripheral CD4+ T cells is associated with inferior clinical response in a subset of patients who received anti-PD-L1 treatment, indicating a potential predictive value of this marker. This work highlights the potential of a non-invasive and effective method to determine prognostic and predictive biomarkers for inhibiting the PD-1 pathway in NSCLC patients.

Proteomic profiling of human plasma identifies apolipoprotein E as being associated with smoking and a marker for squamous metaplasia of the lung

Biomarkers to identify subjects at high‐risk for developing lung cancer will revolutionize the disease outlook. Most biomarker studies have focused on patients already diagnosed with lung cancer and in most cases the disease is often advanced and incurable. The objective of this study was to use proteomics to identify a plasma biomarker for early detection of lung lesions that may subsequently be the harbinger for cancer. Plasma samples were obtained from subjects without lung cancer grouped as never, current, or ex‐smokers. An iTRAQ‐based proteomic analysis was performed on these pooled plasma samples. We identified 31 proteins differentially abundant in current smokers or ex‐smokers relative to never smokers. Western blot and ELISA analyses confirmed the iTRAQ results that demonstrated an increase of apolipoprotein E (APOE) in current smokers as compared to both never and ex‐smokers. There was a strong and significant correlation of the plasma APOE levels with development of premalignant squamous metaplasia. Additionally, we also showed that higher tissue levels of APOE are seen with squamous metaplasia, supporting a direct relationship. Our analysis reveals that elevated plasma APOE is associated with smoking, and APOE is a novel predictive protein biomarker for early morphological changes of squamous metaplasia in the lung.

Pulmonary Rehabilitation in Lung Cancer

Lung cancer remains a challenging disease with high morbidity and mortality despite targeted therapy. Symptom burden related to cancer impairs quality of life and functional status in patients with lung cancer and in survivors. Pulmonary rehabilitation has been recognized as an effective, noninvasive intervention for patients with chronic respiratory disease. It is well established that pulmonary rehabilitation benefits patients with chronic obstruction pulmonary disease through improved exercise capacity and symptoms. Evidence is increasing that the benefit of pulmonary rehabilitation can be applied to patients with lung cancer. Comprehensive pulmonary rehabilitation has made its way as a cornerstone of integrated care for patients with lung cancer.

Clinical Approaches to Immunotherapy in Non-Small Cell Lung Cancer: Current and Future Perspectives.

Lung cancer is among the most prevalent and deadly cancers. Although the development of targeted drugs, erlotinib and crizotinib, has improved lung cancer management, survival rates of lung cancer patients have not shown significant improvement over the past decade. Better therapeutic options are required to treat lung cancer patients. Immunotherapy is a maturing and rapidly growing field, which has recently contributed many novel strategies for addressing cancer treatment. Here, we discuss the current state of cancer vaccines, immune checkpoint blockers, and adoptive cellular therapies, as novel clinical treatment strategies for non-small cell lung cancer. The durability of clinical activity in a subset of patients has led to a great deal of excitement and optimism.

A patient with complex multiple genomic ALK alterations

Lung cancer is a disease with a heterogeneous complement of mutations.1 Although point mutations and deletions are among the most common types of mutations in lung cancer, translocations in the ALK gene, which occur in approximately 5% of lung adenocarcinomas, exist predominantly in non-smokers. ALK translocations gained notoriety recently because they are targets for the kinase inhibitor crizotinib (Xalkori).1 Crizotinib has exhibited profound efficacy and has obtained FDA (United States Food and Drug Administration) approval for use in patients with non-small cell lung cancer (NSCLC) with ALK translocation, as determined by a break-apart fluorescent in situ hybridisation (FISH) assay.2 Here we report a case where a patient with a complicated ALK genotype, including an EML4-ALK variant 5a/b translocation and ALK tandem duplication with response to crizotinib treatment. A 70-year-old female patient with complaints of progressive dyspnoea underwent a chest CT scan, which revealed a 6 cm spiculated mass with extrinsic compression of the trachea and the right main stem bronchus. PET-CT (positron emission tomography-CT) scan confirmed the findings of the CT scan and the mass was metabolically active, and there was presence of metastases in the lymph nodes. Histological evaluation along with immunostaining revealed primary lung adenocarcinoma. An MRI of the brain revealed nodular intraparenchymal metastatic deposits in the left cerebellar hemisphere, left inferior cerebellar vermus and the left superior parietal cortex. The patient received palliative radiation to the lung mass and gamma knife treatment for the brain metastasis. Genetic profiling performed on …