Lysine specific demethylase 1 (LSD1) has been identified and biochemically characterized in epigenetics, but the pathological roles of its dysfunction in lung cancer remain to be elucidated. The aim of this study was to evaluate the prognostic significance of LSD1 expression in patients with non-small cell lung cancer (NSCLC) and to define its exact role in lung cancer proliferation, migration and invasion. The protein levels of LSD1 in surgically resected samples from NSCLC patients were detected by immunohistochemistry or Western blotting. The mRNA levels of LSD1 were detected by qRT-PCR. The correlation of LSD1 expression with clinical characteristics and prognosis was determined by statistical analysis. Cell proliferation rate was assessed by MTS assay and immunofluorescence. Cell migration and invasion were detected by scratch test, matrigel assay and transwell invasion assay. LSD1 expression was higher in lung cancer tissue more than in normal lung tissue. Our results showed that over-expression of LSD1 protein were associated with shorter overall survival of NSCLC patients. LSD1 was localized mainly to the cancer cell nucleus. Interruption of LSD1 using siRNA or a chemical inhibitor, pargyline, suppressed proliferation, migration and invasion of A549, H460 and 293T cells. Meanwhile, over-expression of LSD1 enhanced cell growth. Finally, LSD1 was shown to regulate epithelial-to-mesenchymal transition in lung cancer cells. Over-expression of LSD1 was associated with poor prognosis in NSCLC, and promoted tumor cell proliferation, migration and invasion. These results suggest that LSD1 is a tumor-promoting factor with promising therapeutic potential for NSCLC.

Gasdermin D (GSDMD) is a newly discovered pyroptosis executive protein, which can be cleaved by inflammatory caspases and is essential for secretion of IL‑1β, making it a critical mediator of inflammation. However, the precise role of GSDMD in carcinogenesis remains nearly unknown. Considering the vital role of inflammation in tumorigenesis, we investigated the biological function of GSDMD in non‑small cell lung cancer (NSCLC). Our study demonstrated that the GSDMD protein levels were significantly upregulated in NSCLC compared to these levels in matched adjacent tumor specimens. Higher GSDMD expression was associated with aggressive traits including larger tumor size and more advanced tumor-node-metastasis (TNM) stages. In addition, high GSDMD expression indicated a poor prognosis in lung adenocarcinoma (LUAD), but not in squamous cell carcinoma (LUSC). Knockdown of GSDMD restricted tumor growth in vitro and in vivo. Notably, intrinsic and extrinsic activation of pyroptotic (NLRP3/caspase‑1) signaling in GSDMD‑deficient tumor cells induced another type of programmed cell death (apoptosis), instead of pyroptosis. GSDMD depletion activated the cleavage of caspase‑3 and PARP, and promoted cancer cell death via intrinsic mitochondrial apoptotic pathways. In addition, co‑expression analyses indicated a correlation between GSDMD and EGFR/Akt signaling. Collectively, our results revealed a crosstalk between pyroptotic signaling and apoptosis in tumor cells. Knockdown of GSDMD attenuated tumor proliferation by promoting apoptosis and inhibiting EGFR/Akt signaling in NSCLC. In conclution, GSDMD is an independent prognostic biomarker for LUAD.

Background: We conducted a meta-analysis to evaluate the efficacy of anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) monotherapy or immunotherapy combined with chemotherapy and further estimated the value of PD-L1 expression in predicting the response from anti-PD-1/PD-L1 treatments as monotherapy or in combination with chemotherapy. Methods: Clinical trial data were searched from electronic databases, which evaluated PD-1/PD-L1 inhibitors in non-small cell lung cancer (NSCLC) and correlated with PD-L1 expression levels. Results: Fifteen randomized-controlled trials involving 10,074 patients were identified. Comparing anti-PD-1/PD-L1 monotherapy to chemotherapy, the pooled HR for overall survival (OS) was 0.77 (95% CI: 0.69–0.85, P<0.00001). Subgroup analyses revealed that patients had longer OS at ≥1%, ≥5%, ≥10% and ≥50% PD-L1 expression levels. Patients with higher PD-L1 expression may get increased benefit from PD-1/PD-L1 inhibitors. Moreover, patients with PD-L1 ≥50% had an objective response rate (ORR) improvement from anti-PD-1/PD-L1 therapy (RR =1.87, 95% CI: 1.27–2.75, P=0.001), but no ORR benefits were observed in patients with PD-L1 expression <1% (RR =0.82, 95% CI: 0.56–1.22, P=0.33) or 1–49% (RR =0.80, 95% CI: 0.64–0.98, P=0.03). OS was significantly better in patients receiving second-or-third line treatments (P<0.00001) with PD-L1 ≥1%. The efficacy of PD-1 inhibitors was similar to that of PD-L1 inhibitors, with no significant difference (P=0.63, I²=0%). Furthermore, immunotherapy combined with chemotherapy had better OS (HR =0.64, 95% CI: 0.48–0.84, P=0.001) than chemotherapy alone. Subgroup analyses showed that patients benefited from the combined chemo-IO treatment in the first-line setting regardless of PD-L1 expression level. Conclusions: PD-L1 expression may be a valuable predictor of the efficacy of anti-PD-1/PD-L1 monotherapy in certain NSCLC patients. However, the combination of chemotherapy plus immunotherapy significantly improved survival regardless of the PD-L1 expression level in the first-line treatment of NSCLC.

Sensitizing mutations in epidermal growth factor receptor (EGFR) are associated with positive responses to anti-EGFR-targeted therapy, leading to a new era of treatment for non-small cell lung cancer (NSCLC). Exon 19 deletions and exon 21 L858R substitutions are the most common mutations, accounting for approximately 90% mutations in NSCLC; these are termed classic mutations and result in high sensitivity to tyrosine kinase inhibitors (TKIs). Other EGFR mutations are termed uncommon EGFR mutations, of which G719X, S768I, L861Q, exon 20 insertions, and complex mutations are the most frequent. G719X, S768I, and L861Q are point mutations and those that exist with complex mutations are sensitive to first-generation TKIs. A prospective analysis demonstrated that afatinib, a second-generation TKI, led to a better prognosis in some patients with NSCLC compared to first-generation TKIs. Chemotherapy used to be the traditional choice for patients carrying exon 20 insertions; however, with the development of novel targeted drugs, the role of chemotherapy is changing. Tremendous progress has also been made in clinical trials on immunotherapy treatment of uncommon EGFR mutations. The treatment for patients with NSCLC harboring uncommon EGFR mutations remains a subject of debate and the sensitivity of uncommon EGFR mutations to TKIs is still unclear. Here, we summarized recent data in the literature and provide an overview of the clinical characteristics, incidence, and outcomes of patients harboring G719X, S768I, L861Q, exon 20 insertions, and complex mutations who were treated with TKIs, chemotherapy, or immunotherapy.