Precision Therapy for Lung Cancer: Tyrosine Kinase Inhibitors and Beyond

Bloom Syndrome Protein Activates AKT and PRAS40 in Prostate Cancer Cells

Purpose

Prostate cancer (PC) is a common malignant tumor and a leading cause of cancer-related death in men worldwide. In order to design new therapeutic interventions for PC, an understanding of the molecular events underlying PC tumorigenesis is required. Bloom syndrome protein (BLM) is a RecQ-like helicase, which helps maintain genetic stability. BLM dysfunction has been implicated in tumor development, most recently during PC tumorigenesis. However, the molecular basis for BLM-induced PC progression remains poorly characterized. In this study, we investigated whether BLM modulates the phosphorylation of an array of prooncogenic signaling pathways to promote PC progression.

Methods

We analyzed differentially expressed proteins (DEPs) using iTRAQ technology. Site-directed knockout of BLM in PC-3 prostate cancer cells was performed using CRISPR/Cas9-mediated homologous recombination gene editing to confirm the effects of BLM on DEPs. PathScan® Antibody Array Kits were used to analyze the phosphorylation of nodal proteins in PC tissue. Immunohistochemistry and automated western blot (WES) analyses were used to validate these findings.

Results

We found that silencing BLM in PC-3 cells significantly reduced their proliferative capacity. In addition, BLM downregulation significantly reduced levels of phosphorylated protein kinase B (AKT (Ser473)) and proline-rich AKT substrate of 40 kDa (PRAS40 (Thr246)), and this was accompanied by enhanced ROS (reactive oxygen species) levels. In addition, we found that AKT and PRAS40 inhibition reduced BLM, increased ROS levels, and induced PC cell apoptosis.

Conclusions

We demonstrated that BLM activates AKT and PRAS40 to promote PC cell proliferation and survival. We further propose that ROS act in concert with BLM to facilitate PC oncogenesis, potentially via further enhancing AKT signaling and downregulating PTEN expression. Importantly, inhibiting the BLM-AKT-PRAS40 axis induced PC cell apoptosis. Thus, we highlight new avenues for novel anti-PC treatments.

Lung adenocarcinoma with intraoperatively diagnosed pleural seeding: Is main tumor resection beneficial for prognosis?

OBJECTIVE

To evaluate whether main tumor resection improves survival compared with pleural biopsy alone in patients with lung adenocarcinoma with intraoperatively diagnosed pleural seeding.

METHODS

Forty-three patients with lung adenocarcinoma with pleural seeding diagnosed unexpectedly during surgery performed between January 2006 and December 2014 were included in this retrospective study using a prospectively collected lung cancer database. Each surgeon decided whether to perform main tumor resection or pleural biopsy alone.

RESULTS

Main tumor and visible pleural nodule resection was performed in 30 patients (tumor resection group). The remaining 13 patients underwent pleural nodule biopsy alone (open-close group). The clinical T stage was higher in the open-close group than in the tumor resection group (P = .02). The tumor resection group had longer operative times compared with the open-close group (mean, 141.8 vs 80.3 minutes). There were no other statistically significant differences in perioperative parameters. The surgical method was the sole statistically significant prognostic factor. Patients in the tumor resection group had better progression-free survival (3-year survival: 44.5% vs 0%; P = .009) and overall survival (3-year survival: 82.9% vs 38.5%; P = .013) than did the open-close group. There was no significant survival difference between sublobar resection and lobectomy for the main tumor resection.

CONCLUSIONS

Our study demonstrated improved progression-free and overall survival after main tumor and visible pleural nodule resection in patients with lung adenocarcinoma with intraoperatively diagnosed pleural seeding. Further randomized trials are needed to define the role of main tumor resection in these patients.

ASXL3 Is a Novel Pluripotency Factor in Human Respiratory Epithelial Cells and a Potential Therapeutic Target in Small Cell Lung Cancer

In this study, we generated induced pluripotent stem cells (iPSC) from normal human small airway epithelial cells (SAEC) to investigate epigenetic mechanisms of stemness and pluripotency in lung cancers. We documented key hallmarks of reprogramming in lung iPSCs (Lu-iPSC) that coincided with modulation of more than 15,000 genes relative to parental SAECs. Of particular novelty, we identified the PRC2-associated protein, ASXL3, which was markedly upregulated in Lu-iPSCs and small cell lung cancer (SCLC) lines and clinical specimens. ASXL3 overexpression correlated with increased genomic copy number in SCLC lines. ASXL3 silencing inhibited proliferation, clonogenicity, and teratoma formation by Lu-iPSCs, and diminished clonogenicity and malignant growth of SCLC cells in vivo Collectively, our studies validate the utility of the Lu-iPSC model for elucidating epigenetic mechanisms contributing to pulmonary carcinogenesis and highlight ASXL3 as a novel candidate target for SCLC therapy. Cancer Res; 77(22); 6267-81. ©2017 AACR.

Validity of the Asthma Control Test Questionnaire Among Smoking Asthmatics

BACKGROUND

Smoking asthmatics respond worse to existing asthma therapies and have more asthma symptoms and exacerbations.

OBJECTIVE

We evaluated the Asthma Control Test (ACT) for assessing asthma control among smokers.

METHODS

Adults with asthma who smoked were enrolled and followed for 6 weeks. The statistical properties, validity, and responsiveness of the ACT were evaluated. Physician global assessment (GS) of asthma was the "gold standard."

RESULTS

A total of 151 participants were enrolled: 52% female and 48% male. The median (interquartile ranges) was 35 (27, 43) years for age, 11 (7, 18) for pack-years, and 16 (13, 20) for the ACT score. Participants self-identified as African American (49%), non-Hispanic whites (38%), and Hispanic whites (11%). Participants were classified as well controlled (24%), not well controlled (42%), or very poorly controlled (34%) at enrollment. Cronbach's alpha (95% confidence interval [CI]) for the ACT at enrollment was 0.81 (0.76, 0.85). The intraclass correlation coefficient (95% CI) for agreement of scores at enrollment and 6 weeks was 0.68 (0.57, 0.78) in participant with stable asthma (n = 93). ACT scores were associated with GS (P < .001). Area under the receiver operating characteristic (ROC) curve (95% CI) for an ACT cutoff score of ≤19 (not well controlled) was 0.76 (0.67, 0.84). The ACT score with the maximum area under the ROC curve was 18.6.

CONCLUSIONS

The ACT questionnaire was reliable and discriminated between levels of asthma control in smoking asthmatics with similar sensitivity and specificity as nonsmoking asthmatics, which confirms its value as a tool for the management of asthma in this prevalent but understudied subgroup of subjects.

Nivolumab, anti-programmed death-1 (PD-1) monoclonal antibody immunotherapy: Role in advanced cancers

The development of immune checkpoint inhibitors has altered the landscape of treatment of advanced cancers. These drugs are well tolerated and have shown clinical activity against a wide variety of solid tumors and hematological malignancies. The durability of response is particularly impressive when compared to other forms of systemic therapy. Nivolumab (Opdivo) is an IgG4 antibody that causes immune checkpoint blockade by diminishing inhibitory signaling through the programmed death receptor-1 pathway. It is approved for treatment of recurrent non-small cell lung cancer, melanoma, and renal cell carcinoma. Efforts to identify biomarkers of response to nivolumab are ongoing. Clinical trials are also being conducted to determine the benefits of combining nivolumab with other forms of treatment including chemotherapy, molecular-targeted therapy, radiation therapy, and other forms of immune therapy. This review outlines the clinical trials that have led to the emergence of nivolumab as a treatment option for patients with advanced cancers.