Squamous cell lung cancer: from tumor genomics to cancer therapeutics

[Exploring the Role of PCDHGB4 in the Occurrence of Lung Squamous Cell Carcinoma Based on Bioinformatics Analysis]

BACKGROUND

Lung squamous cell carcinoma (LUSC) is a subtypes of non-small cell lung cancer (NSCLC). It has been reported that members of the protocadherin γ family can regulate tumor cell growth by inhibiting the Wnt signaling pathway. Protocadherin-gamma subfamily B4 (PCDHGB4) as a family member in LUSC was rarely reported. The aim of this study was to investigate the role and potential prognostic value of PCDHGB4 in the development of LUSC using bioinformatics methods.

METHODS

The Cancer Genome Atlas (TCGA), cBioPortal and UALCAN databases were used to analyze the expression, prognosis, clinicopathological features, immune cell infiltration, immune regulatory genes, immune checkpoint inhibitors (ICIs), and methyltransferases of PCDHGB4 in LUSC. At the single cell level, we analyzed the clustering results of cell subtypes and the expression of PCDHGB4 in different immune cell subpopulations. In addition, we compared the promoter methylation levels of PCDHGB4 in LUSC tissues and normal tissues and performed protein-protein interaction and mutation analysis. Finally, enrichment analysis was performed based on the differentially expressed genes.

RESULTS

Bioinformatics analysis results showed that the expression level of PCDHGB4 in LUSC tissues was lower than that in normal tissues. Survival analysis showed that increased PCDHGB4 expression was associated with poor prognosis. Single-cell sequencing analysis showed that PCDHGB4 was expressed in T cells, monocytes or macrophages, and dendritic cells. It was further found that PCDHGB4 played an important role in tumor immunity and confirmed that PCDHGB4 was associated with immune checkpoints, immune regulatory genes, and methyltransferases. Besides, enrichment analysis revealed that PCDHGB4 was involved in multiple cancer-related pathways.

CONCLUSIONS

The expression of PCDHGB4 was low in LUSC. PCDHGB4 was related to the poor prognosis of patients, and PCDHGB4 was closely related to the infiltration and pathway of tumor immune cells. PCDHGB4 may be a potential prognostic marker and a new target for immunotherapy in LUSC.

Expression and Purification of FGFR1-Fc Fusion Protein and Its Effects on Human Lung Squamous Carcinoma

Molecular-targeted therapies for lung squamous cell carcinoma (LSCC) are limited mainly because targetable oncogenic aberrations are absent in LSCC. Recent genomic analyses have revealed that the fibroblast growth factor (FGF) signaling pathway plays a fundamental role in LSCC progression via cancer cell proliferation and angiogenesis. In the present study, we designed, expressed, and purified a fibroblast growth factor receptor fragment (FGFR1-Fc) fusion protein using NS/0 cells. In FGF2-FGFR1 overexpressed NCI-H1703 cells, the FGFR1-Fc fusion protein effectively inhibited proliferation and invasion and arrested the cell cycle at the G0-G1 phase. In NCI-H1703 cells treated with the FGFR1-Fc fusion protein, the phosphorylation levels of FGFR1, FRS2, ERK, and AKT were significantly reduced. Using an siRNA assay, we demonstrated that FGF2-FGFR1 is the major anti-tumor target of FGFR1-Fc fusion the FGFR1-Fc fusion protein, which also significantly inhibited proliferation and invasion by NCI-H1703 cells via the FGF2-FGFR1 signaling pathway. In addition, the FGFR1-Fc fusion protein significantly inhibited angiogenesis in an embryonic chorioallantoic membrane model. The FGFR1-Fc fusion protein may be an effective therapeutic candidate for LSCC.

Licochalcone A induces cell cycle arrest and apoptosis via suppressing MAPK signaling pathway and the expression of FBXO5 in lung squamous cell cancer

Lung squamous cell carcinoma (LSCC) is a highly heterogeneous malignancy with high mortality and few therapeutic options. Licochalcone A (LCA, PubChem ID: 5318998) is a chalcone extracted from licorice and possesses anticancer and anti‑inflammatory activities. The present study aimed to elucidate the anticancer effect of LCA on LSCC and explore the conceivable molecular mechanism. MTT assay revealed that LCA significantly inhibited the proliferation of LSCC cells with less cytotoxicity towards human bronchial epithelial cells. 5‑ethynyl‑2'‑deoxyuridine (EdU) assay demonstrated that LCA could reduce the proliferation rate of LSCC cells. The flow cytometric assays indicated that LCA increased the cell number of the G1 phase and induced the apoptosis of LSCC cells. LCA downregulated the protein expression of cyclin D1, cyclin E, CDK2 and CDK4. Meanwhile, LCA increased the expression level of Bax, cleaved poly(ADP‑ribose)polymerase‑1 (PARP1) and caspase 3, as well as downregulated the level of Bcl‑2. Proteomics assay demonstrated that LCA exerted its antitumor effects via inhibiting mitogen‑activated protein kinase (MAPK) signaling pathways and the expression of F‑box protein 5 (FBXO5). Western blot analysis showed that LCA decreased the expression of p‑ERK1/2, p‑p38MAPK and FBXO5. In the xenograft tumors of LSCC, LCA significantly inhibited the volumes and weight of tumors in nude mice with little toxicity in vital organs. Therefore, the present study demonstrated that LCA effectively inhibited cell proliferation and induced apoptosis in vitro, and suppressed xenograft tumor growth in vivo. LCA may serve as a future therapeutic candidate of LSCC.

Immune-active tumor-adjacent tissues are associated with favorable prognosis in stage I lung squamous cell carcinoma

The immunogenomic features of tumor-adjacent lungs (TALs) in stage I lung squamous cell carcinoma (LUSC) are not clear. Multiomics analyses of tumor tissues and paired TALs from 59 stage I LUSC patients were performed. Compared to tumors, TALs exhibited a better-preserved immune contexture indicated by upregulation of immune pathways, increased immune infiltration, and higher expression of immune effector molecules. Notably, TALs had no mutations in PTEN and KEAP1, a lower incidence of human leukocyte antigen (HLA) loss and higher expression of HLA class I genes, major histocompatibility complex (MHC) I chaperones, and interferon (IFN)-γ-associated genes. Digital spatial profiling validated the generally higher immune infiltration in TALs and revealed a higher level of immune heterogeneity in LUSC tumors. Importantly, patients with higher immune infiltration in TALs had significantly longer survival, while high immune heterogeneity was associated with inferior patient survival. Our work can be considered in the selection of patients for adjuvant therapy, especially immunotherapy.

Identification of prognostic immune subtypes of lung squamous cell carcinoma by unsupervised consistent clustering

We performed UCC on the expression data of lung squamous cell carcinoma tumor samples to identify the classification of lung squamous cell carcinoma (LUSC) tumor samples, and calculated the levels of different classified immune cells by single-sample gene enrichment analysis (ssGSEA) to obtain a set of immune-related subtype gene tags, which can be used for subtype classification of lung squamous cell carcinoma. TCGA-LUSC and GSE30219 data of lung squamous cell carcinoma were obtained from TCGA and GEO databases. Prognostic-associated subtypes were identified by unsupervised consensus clustering (UCC). Using ssGSEA analysis to calculate the level of immune cells of different subtypes, obtain the connection between subtypes and immunity, identify the gene signatures recognized by subtypes, and verify this group of gene signatures through GSE30219. We effectively identified 2 subtypes that were significantly associated with prognostic survival by UCC, and calculated according to ssGSEA, the 2 subtypes were significantly different at the level of immune cells, followed by introducing a This weighted thinking computes a set of gene signatures that are significantly associated with subtype 1. During validation, this set of gene signatures could efficiently and robustly identify distinct prognostic immune subtypes, demonstrated the validity of this set of gene signatures, as well as 2 subtypes of lung squamous cell carcinoma. We used lung squamous cell carcinoma data from public databases and identified 2 prognostic immunosubtypes of lung squamous cell carcinoma and a set of gene tags that can be used to classify immune subtypes of lung squamous cell carcinoma, which may provide effective evidence for accurate clinical treatment of lung squamous cell carcinoma.

Targeted EGFR Nanotherapy in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality worldwide. Despite advances in treatment, the prognosis remains poor, highlighting the need for novel therapeutic strategies. The present review explores the potential of targeted epidermal growth factor receptor (EGFR) nanotherapy as an alternative treatment for NSCLC, showing that EGFR-targeted nanoparticles are efficiently taken up by NSCLC cells, leading to a significant reduction in tumor growth in mouse models. Consequently, we suggest that targeted EGFR nanotherapy could be an innovative treatment strategy for NSCLC; however, further studies are needed to optimize the nanoparticles and evaluate their safety and efficacy in clinical settings and human trials.

The relationship of airflow limitation with lung squamous cell carcinoma: evidence from mendelian randomization analysis

BACKGROUND

Observational studies showed associations between smoking, and airflow limitation, with lung squamous cell carcinoma (LUSC). However, the causal association of airflow limitation with LUSC and the modification by smoking status for the association remains unclear.

METHODS

Genetic summary data were obtained from large genome-wide association studies (GWAS). One hundred two single nucleotide polymorphisms (SNPs) for airflow limitation (i.e., FEV1/FVC < 0.7) and 153 SNPs for smoking behavior were used as instrumental variables and the main MR analysis methods. The univariable and multivariable Mendelian Randomization (MR) in a two-sample setting were performed to assess the association of airflow limitation, and smoking behavior with LUSC.

RESULTS

In the univariable MR analysis, genetic predisposition towards airflow limitation [Inverse Variance-Weighted (IVW) method Odds Ratio (OR) = 4.83, 95% Confidence Interval (CI) 1.55 to 15.06, P = 0.006], age of smoking initiation (IVW method OR = 0.10, 95%CI 0.02 to 0.36, P < 0.001), cigarettes smoked per day (IVW method OR = 3.10, 95%CI 2.07 to 4.63, P < 0.001), ex-smoking (IVW method OR = 0.47, 95%CI 0.31 to 0.69, P < 0.001), current smoking status (IVW method OR = 13.08, 95%CI 2.53 to 67.84, P = 0.002), pack-years of smoking (Weighted median method OR = 11.49, 95%CI 3.71 to 35.63, P < 0.001) were associated with LUSC. In the multivariable MR analysis, the causal effect of airflow limitation was still observed on LUSC (IVW method OR = 2.97, 95% CI 1.09 to 8.04, P = 0.032 adjusted for age of smoking initiation and cigarettes smoked per day; IVW method OR = 3.24, 95% CI 1.09 to 9.58, P = 0.033 adjusted for ex-smoking, current smoking status, and pack years of smoking; IVW method OR = 2.91, 95% CI 1.01 to 8.41, P = 0.049 adjusted for 5 smoking behaviors mentioned above).

CONCLUSIONS

Our MR analysis demonstrated that airflow limitation is likely to be an independent predictor of LUSC.

Molecular Biology and Therapeutic Targets of Primitive Tracheal Tumors: Focus on Tumors Derived by Salivary Glands and Squamous Cell Carcinoma

Primary tracheal tumors are rare, constituting approximately 0.1-0.4% of malignant diseases. Squamous cell carcinoma (SCC) and adenoid cystic carcinoma (ACC) account for about two-thirds of these tumors. Despite most primary tracheal cancers being eligible for surgery and/or radiotherapy, unresectable, recurrent and metastatic tumors may require systemic treatments. Unfortunately, the poor response to available chemotherapy as well as the lack of other real therapeutic alternatives affects the quality of life and outcome of patients suffering from more advanced disease. In this condition, target therapy against driver mutations could constitute an alternative to chemotherapy, and may help in disease control. The past two decades have seen extraordinary progress in developing novel target treatment options, shifting the treatment paradigm for several cancers such as lung cancer. The improvement of knowledge regarding the genetic and biological alterations, of major primary tracheal tumors, has opened up new treatment perspectives, suggesting the possible role of biological targeted therapies for the treatment of these rare tumors. The purpose of this review is to outline the state of knowledge regarding the molecular biology, and the preliminary data on target treatments of the main primary tracheal tumors, focusing on salivary-gland-derived cancers and squamous cell carcinoma.

Comprehensive analyses of a CD8+ T cell infiltration related gene signature with regard to the prediction of prognosis and immunotherapy response in lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC) is associated with a worse prognosis than other histological subtypes of non-small cell lung cancer. Due to the vital role of CD8⁺ T cells in anti-tumor immunity, the characterization of CD8⁺ T cell infiltration-related (CTLIR) gene signature in LUSC is worthy of in-depth exploration. In our study, tumor tissues of LUSC patients from Renmin Hospital of Wuhan University were stained by multiplex immunohistochemistry to evaluate the density of infiltrated CD8⁺ T cells and explore the correlation with immunotherapy response. We found that the proportion of LUSC patients who responded to immunotherapy was higher in the high density of CD8⁺ T cell infiltration group than in the low density of CD8⁺ T cell infiltration group. Subsequently, we collected bulk RNA-sequencing data from The Cancer Genome Atlas (TCGA) database. The abundance of infiltrating immune cells in LUSC patients was analyzed by using CIBERSORT algorithm, and weighted correlation network analysis was performed to identify the co-expressed gene modules related to CD8⁺ T cells. We then developed a prognostic gene signature based on CD8⁺ T cell co-expressed genes and calculated the CTLIR risk score, which stratified LUSC patients into high-risk and low-risk groups. With univariate and multivariate analyses, the gene signature was identified as an independent prognostic factor in LUSC patients. The overall survival of LUSC patients in the high-risk group was significantly shorter than that of the low-risk group in the TCGA cohort, which was validated in Gene Expression Omnibus datasets. We analyzed immune cell infiltration in the tumor microenviroment and found fewer CD8⁺ T cells and more regulatory T cell infiltration in the high-risk group, which is characterized as an immunosuppressive phenotype. Furthermore, the LUSC patients in the high-risk group were predicted to have a better response to immunotherapy than those in the low-risk group when treated with PD-1 and CTLA4 inhibitors. In conclusion, we performed a comprehensive molecular analysis of the CTLIR gene signature in LUSC and constructed a risk model for LUSC patients to predict prognosis and immunotherapy response.

Metabolomic differentiation of benign vs malignant pulmonary nodules with high specificity via high-resolution mass spectrometry analysis of patient sera

Differential diagnosis of pulmonary nodules detected by computed tomography (CT) remains a challenge in clinical practice. Here, we characterize the global metabolomes of 480 serum samples including healthy controls, benign pulmonary nodules, and stage I lung adenocarcinoma. The adenocarcinoma demonstrates a distinct metabolomic signature, whereas benign nodules and healthy controls share major similarities in metabolomic profiles. A panel of 27 metabolites is identified in the discovery cohort (n = 306) to distinguish between benign and malignant nodules. The discriminant model achieves an AUC of 0.915 and 0.945 in the internal validation (n = 104) and external validation cohort (n = 111), respectively. Pathway analysis reveals elevation in glycolytic metabolites associated with decreased tryptophan in serum of lung adenocarcinoma vs benign nodules and healthy controls, and demonstrates that uptake of tryptophan promotes glycolysis in lung cancer cells. Our study highlights the value of the serum metabolite biomarkers in risk assessment of pulmonary nodules detected by CT screening.

Pacritinib inhibits glucose consumption in squamous cell lung cancer cells by targeting FLT3

Squamous cell lung cancer maintains its growth through elevated glucose consumption, but selective glucose consumption inhibitors are lacking. Here, we discovered using a high-throughput screen new compounds that block glucose consumption in three squamous cell lung cancer cell lines and identified 79 compounds that block glucose consumption in one or more of these cell lines. Based on its ability to block glucose consumption in all three cell lines, pacritinib, an inhibitor of FMS Related Receptor Tyrosine Kinase 3 (FLT3) and Janus Kinase 2 (JAK2), was further studied. Pacritinib decreased glucose consumption in squamous cell lung cancer cells in cell culture and in vivo without affecting glucose consumption in healthy tissues. Pacritinib blocked hexokinase activity, and Hexokinase 1 and 2 mRNA and protein expression. Overexpression of Hexokinase 1 blocked the ability of pacritinib to inhibit glucose consumption in squamous cell lung cancer cells. Overexpression of FLT3 but not JAK2 significantly increased glucose consumption and blocked the ability of pacritinib to inhibit glucose consumption in squamous cell lung cancer cells. Additional FLT3 inhibitors blocked glucose consumption in squamous cell lung cancer cells. Our study identifies FLT3 inhibitors as a new class of inhibitors that can block glucose consumption in squamous cell lung cancer.

KMT2D deficiency drives lung squamous cell carcinoma and hypersensitivity to RTK-RAS inhibition

Lung squamous cell carcinoma (LUSC) represents a major subtype of lung cancer with limited treatment options. KMT2D is one of the most frequently mutated genes in LUSC (>20%), and yet its role in LUSC oncogenesis remains unknown. Here, we identify KMT2D as a key regulator of LUSC tumorigenesis wherein Kmt2d deletion transforms lung basal cell organoids to LUSC. Kmt2d loss increases activation of receptor tyrosine kinases (RTKs), EGFR and ERBB2, partly through reprogramming the chromatin landscape to repress the expression of protein tyrosine phosphatases. These events provoke a robust elevation in the oncogenic RTK-RAS signaling. Combining SHP2 inhibitor SHP099 and pan-ERBB inhibitor afatinib inhibits lung tumor growth in Kmt2d-deficient LUSC murine models and in patient-derived xenografts (PDXs) harboring KMT2D mutations. Our study identifies KMT2D as a pivotal epigenetic modulator for LUSC oncogenesis and suggests that KMT2D loss renders LUSC therapeutically vulnerable to RTK-RAS inhibition.

Efficacy and safety of pembrolizumab versus sintilimab treatment in patients with advanced squamous lung cancer: A real-world study in China

Importance

Both pembrolizumab and sintilimab have been approved by the Chinese State Drug Administration (NMPA) for the first-line treatment of patients with advanced squamous lung cancer. The differences of the two drugs in efficacy and safety are unclear.

Objectives

To compare the real-world efficacy and safety of first-line treatments in patients with advanced squamous lung cancer.

Materials and methods

This was a retrospective review of patients with advanced squamous carcinoma who received sintilimab or pembrolizumab in combination with chemotherapy as first-line therapy between June 2018 and April 2022 in the Chinese PLA Hospital. The primary objective was to compare the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) between the two groups. Secondary objectives were to compare the disease control rate (DCR) and to analyze adverse events (AEs) between the two groups.

Results

A total of 164 patients were enrolled, including 63 patients (38.4%) in the sintilimab-combined chemotherapy group and 101 patients (61.6%) in the pembrolizumab-combined chemotherapy group. The ORR was 65.10% in the sintilimab group and 61.40% in the pembrolizumab group (P=0.634). The DCR was 92.10% and 92.10% in the sintilimab and pembrolizumab groups, respectively (P=0.991). The median PFS was 22.2 months for patients treated with sintilimab group compared with 16.5 months for patients treated with pembrolizumab group[hazard ratio (HR) = 0.743; 95% confidence interval (CI): 0.479-1.152; P = 0.599]. Patients treated with pembrolizumab did not achieve a median OS, and patients treated with sintilimab had a median OS of 30.7 months. In the sintilimab group, the incidence of all treatment-related adverse events (TRAEs) was 92.1% (58/63), and the incidence of grade 3-4 TRAEs of 42.9% (27/63). In the pembrolizumab group, the incidence of all TRAEs was 90.1% (91/101), and the incidence of grade 3-4 TRAEs was 37.6% (38/101).

Conclusion

In the clinical treatment of Chinese patients with advanced squamous lung cancer, first-line treatment with sintilimab in combination with chemotherapy provided similar efficacy to pembrolizumab in combination with chemotherapy, and the treatment-related adverse effect profiles were comparable between the two groups, including similar rates of grade 3-4 and all adverse events.

A Genomically and Clinically Annotated Patient-Derived Xenograft Resource for Preclinical Research in Non-Small Cell Lung Cancer

Patient-derived xenograft (PDX) models are an effective preclinical in vivo platform for testing the efficacy of novel drugs and drug combinations for cancer therapeutics. Here we describe a repository of 79 genomically and clinically annotated lung cancer PDXs available from The Jackson Laboratory that have been extensively characterized for histopathologic features, mutational profiles, gene expression, and copy-number aberrations. Most of the PDXs are models of non-small cell lung cancer (NSCLC), including 37 lung adenocarcinoma (LUAD) and 33 lung squamous cell carcinoma (LUSC) models. Other lung cancer models in the repository include four small cell carcinomas, two large cell neuroendocrine carcinomas, two adenosquamous carcinomas, and one pleomorphic carcinoma. Models with both de novo and acquired resistance to targeted therapies with tyrosine kinase inhibitors are available in the collection. The genomic profiles of the LUAD and LUSC PDX models are consistent with those observed in patient tumors from The Cancer Genome Atlas and previously characterized gene expression-based molecular subtypes. Clinically relevant mutations identified in the original patient tumors were confirmed in engrafted PDX tumors. Treatment studies performed in a subset of the models recapitulated the responses expected on the basis of the observed genomic profiles. These models therefore serve as a valuable preclinical platform for translational cancer research.

SIGNIFICANCE

Patient-derived xenografts of lung cancer retain key features observed in the originating patient tumors and show expected responses to treatment with standard-of-care agents, providing experimentally tractable and reproducible models for preclinical investigations.

CRISPR-mediated MECOM depletion retards tumor growth by reducing cancer stem cell properties in lung squamous cell carcinoma

Targeted therapy for lung squamous cell carcinoma (LUSC) remains a challenge due to the lack of robust targets. Here, we identified MECOM as a candidate of therapeutic target for LUSC by screening 38 genes that were commonly amplified in three pairs of primary tumors and patient-derived xenografts (PDXs) using a clustered regularly interspaced short palindromic repeats (CRISPR)-mediated approach. High MECOM expression levels were associated with poor prognosis. Forced expression of MECOM in LUSC cell lines promoted cancer stem cell (CSC) properties, and its knockout inhibited CSC phenotypes. Furthermore, systemic delivery of CRISPR-mediated MECOM depletion cassette using adenovirus with an adaptor, which is composed of a single-chain fragment variable (scFv) against epithelial cell adhesion molecules (EpCAM) fused to the ectodomain of coxsackievirus and adenovirus receptor, and a protector, which consists of the scFv connected to the hexon symmetry of the adenovirus, could specifically target subcutaneous and orthotopic LUSC and retard tumor growth. This study could provide a novel therapeutic strategy for LUSC with high efficacy and specificity.

Pathologic response and safety to neoadjuvant PD-1 inhibitors and chemotherapy in resectable squamous non-small-cell Lung cancer

Background

Several randomized studies have shown that the combination of programmed cell death 1 (PD-1) inhibitor and chemotherapy is efficacious as a treatment for advanced non-small-cell lung cancer (NSCLC). However, in the neoadjuvant setting, there is scarce evidence of the effectiveness and safety of the combinations in squamous NSCLC. We conducted a retrospective study to evaluate neoadjuvant PD-1 inhibitor plus chemotherapy in resectable squamous NSCLC.

Methods

Patients from Beijing Chest Hospital, Capital Medical University, between October 2019 and October 2021, treated with PD-1 inhibitors and chemotherapy for resectable squamous NSCLC were retrospectively studied. The primary objectives were to assess the pathological tumor response and safety of neoadjuvant PD-1 inhibitors and chemotherapy.

Results

63 patients with resectable squamous NSCLC stage IIA-IIIB were included. Two to four cycles of PD-1 inhibitors (37 cases with camrelizumab, 11 cases with toripalimab, 8 cases with tislelizumab, and 7 cases with sintilimab) and chemotherapy were administered prior to surgery. 42 patients (66.7%) achieved a major pathologic response (MPR), including 25 (39.7%) with a pathologic complete response (pCR). Twenty-one patients (33.3%) experienced grade 3 neoadjuvant treatment-related adverse events (TRAEs), and no patient had grade 4 or 5 TRAE.

Conclusion

Neoadjuvant PD-1 inhibitors and chemotherapy are feasible therapies for resectable squamous NSCLC. It was associated with a 66.7% MPR rate, 39.7% pCR rate, and tolerable toxicity.

Rigid Tissue Increases Cytoplasmic pYAP Expression in Pre-Malignant Stage of Lung Squamous Cell Carcinoma (SCC) In Vivo

Increased tissue rigidity is able to activate the Hippo signaling pathway, leading to YAP inactivation by phosphorylation and translocation into the cytoplasm. Accumulating evidence suggests that cytoplasmic pYAP serves as a tumor suppressor and could be a prognostic biomarker for several solid cancers. However, the relationship between tissue rigidity and cytoplasmic pYAP expression in the early stage of lung squamous cell carcinoma (SCC) remains elusive; this was determined in this study by using a mouse model. Female BALB/c mice were assigned into two groups (n = 6; the vehicle (VC) and the pre-malignant (PM) group, which received 70% acetone and 0.04 M N-nitroso-tris-chloroethylurea (NTCU) for 15 weeks, respectively. In this study, the formation of hyperplasia and metaplasia lesions was found in the PM group, indicating the pre-malignant stage of lung SCC. The pre-malignant tissue appeared to be more rigid as characterized by significantly higher (p < 0.05) epithelium thickness, proliferative activity, and collagen content than the VC group. The PM group also had a significantly higher (p < 0.05) cytoplasmic pYAP protein expression than the VC group. In conclusion, increased tissue rigidity may contribute to the upregulation of cytoplasmic pYAP expression, which may act as a tumor suppressor in the early stage of lung SCC.

Endogenous sex hormones, aromatase activity and lung cancer risk in postmenopausal never-smoking women

Although reproductive factors have been repeatedly associated with lung cancer risk, no study to date has directly evaluated the relationship with endogenous sex hormones nor with aromatase activity in postmenopausal never-smoking women. A case-control study of 397 incident lung cancer cases and their individually matched controls, nested within the Shanghai Women's Health Study, was conducted among postmenopausal women who were lifetime never smokers. Prediagnostic concentrations of sex hormones was quantitated using LC-MS/MS assays in plasma. The product-substrate molar ratio of estrone to androstenedione was used as an index of aromatase activity (IAA). Multivariable conditional logistic regression models were used to calculate odds ratios (ORs) for lung cancer. Baseline concentrations of estradiol, free testosterone and IAA were inversely associated with subsequent risk of lung cancer in multivariable-adjusted models. When further adjusted for body mass index, the inverse association with estradiol was attenuated and no longer statistically significant, but the association with free testosterone and IAA remained. In analyses confined to participants having never used menopausal hormone therapy in 376 case-control pairs, the inverse association with free testosterone and IAA was slightly strengthened. OR for the highest vs the lowest quartile of free testosterone was 0.55 (95% CI = 0.34-0.90; Ptrend  = .03), and the corresponding OR for IAA was 0.57 (95% CI = 0.34-0.96; Ptrend  = .04). Our study, for the first time, suggests that higher levels of circulating free testosterone and estimated aromatase activity may be associated with lower lung cancer risk in postmenopausal never-smoking women.

Palbociclib Induces the Apoptosis of Lung Squamous Cell Carcinoma Cells via RB-Independent STAT3 Phosphorylation

Lung squamous cell carcinoma (LUSC) treatment response is poor and treatment alternatives are limited. Palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, has recently been approved for hormone receptor-positive breast cancer patients and applied in multiple preclinical models, but its use for LUSC therapy remains elusive. Here, we investigated whether palbociclib induced cell apoptosis and dissected the underlying mechanism in LUSC. We found that palbociclib induced LUSC cell apoptosis through inhibition of Src tyrosine kinase/signal transducers and activators of transcription 3 (STAT3). Interestingly, palbociclib reduced STAT3 signaling in LUSC cells interfered by retinoblastoma tumor-suppressor gene (RB), suggesting that pro-apoptosis effect of palbociclib was independent of classic CDK4/6-RB signaling. Furthermore, palbociclib could suppress IL-1β and IL-6 expression, and therefore blocked Src/STAT3 signaling, which were rescued by either recombinant human IL-1β or IL-6. Moreover, Myc mediated the sensitivity of LUSC cells to palbociclib. Our discoveries demonstrated that palbociclib induces apoptosis of LUSC cells through the Src/STAT3 axis in an RB-independent manner, and provided a reliable experimental basis of clinical studies in LUSC patients.

DNA damage repair gene signature model for predicting prognosis and chemotherapy outcomes in lung squamous cell carcinoma

BACKGROUND

Lung squamous cell carcinoma (LUSC) is prone to metastasis and likely to develop resistance to chemotherapeutic drugs. DNA repair has been reported to be involved in the progression and chemoresistance of LUSC. However, the relationship between LUSC patient prognosis and DNA damage repair genes is still unclear.

METHODS

The clinical information of LUSC patients and tumour gene expression level data were downloaded from the TCGA database. Unsupervised clustering and Cox regression were performed to obtain molecular subtypes and prognosis-related significant genes based on a list including 150 DNA damage repair genes downloaded from the GSEA database. The coefficients determined by the multivariate Cox regression analysis and the expression level of prognosis-related DNA damage repair genes were employed to calculate the risk score, which divided LUSC patients into two groups: the high-risk group and the low-risk group. Immune viability, overall survival, and anticarcinogen sensitivity analyses of the two groups of LUSC patients were performed by Kaplan-Meier analysis with the log rank test, ssGSEA and the pRRophetic package in R software. A time-dependent ROC curve was applied to compare the survival prediction ability of the risk score, which was used to construct a survival prediction model by multivariate Cox regression. The prediction model was used to build a nomogram, the discriminative ability of which was confirmed by C-index assessment, and its calibration was validated by calibration curve analysis. Differentially expressed DNA damage repair genes in LUSC patient tissues were retrieved by the Wilcoxon test and validated by qRT-PCR and IHC.

RESULT

LUSC patients were separated into two clusters based on molecular subtypes, of which Cluster 2 was associated with worse overall survival. A prognostic prediction model for LUSC patients was constructed and validated, and a risk score calculated based on the expression levels of ten DNA damage repair genes was employed. The clinical utility was evaluated by drug sensitivity and immune filtration analyses. Thirteen-one genes were upregulated in LUSC patient samples, and we selected the top four genes that were validated by RT-PCR and IHC.

CONCLUSION

We established a novel prognostic model based on DNA damage repair gene expression that can be used to predict therapeutic efficacy in LUSC patients.

A Ferroptosis-Related Gene Signature for Overall Survival Prediction and Immune Infiltration in Lung Squamous Cell Carcinoma

Background: Ferroptosis is associated with cancer initiation and progression. However, the molecular mechanism and prognostic value of ferroptosis-related genes in lung squamous cell carcinoma (LUSC) are poorly understood.

Methods: The mRNA expression profiles, methylation data, and clinical information of patients with LUSC were downloaded from TCGA and GEO database. Ferroptosis-related differentially expressed genes (DEGs) were identified between cancerous and non-cancerous tissues, and their prognostic value was systemically investigated by bioinformatic analyses.

Results: A ferroptosis-related gene signature (ALOX5, TFRC, PHKG2, FADS2, NOX1) was constructed using multivariate Cox regression analysis and represented as a risk score. Overall survival (OS) probability was significantly lower in the high-risk group than in the low-risk group (P<0.001), and receiver operating characteristic curve showed a good predictive capacity (AUC = 0.739). The risk score was an independent prognostic factor for LUSC. A nomogram was constructed to predict the OS probabilities at 1, 3, and 5 years. High-risk score was associated with increased immune infiltration, lower methylation levels, higher immune checkpoint genes expression levels, and better chemotherapy response. Cell adhesion molecules, focal adhesion, and extracellular matrix receptor interaction were the main pathways in the high-risk group. The signature was validated using the TCGA test cohort, entire TCGA cohort, GSE30219, GSE157010, GSE73403, and GSE4573 datasets. The gene disorders in patients with LUSC were validated using real-time PCR and single-cell RNA sequencing analysis.

Conclusions: A ferroptosis-related gene signature was constructed to predict OS probability in LUSC. This could facilitate novel therapeutic methods and guide individualized therapy.

[Clinical Observation of Immunotherapy Efficacy and Adverse Effects in Chinese Patients with Lung Squamous Cell Carcinoma]

BACKGROUND

Immune checkpoint inhibitors (ICIs) improved survival of partial patients with lung squamous cell carcinoma (LUSC). However, it was still insufficient of data in older patients. This study aimed to investigate the efficacy and toxicity of immunotherapy in patients with LUSC in Chinese population of real world.

METHODS

A total of 185 LUSC patients underwent pathological diagnosis were involved from January 2018 to January 2022. Patients were divided into elderly group (age ≥70 years) and younger group (age <70 years). The efficacy of mono-immunotherapy or combined with chemotherapy to chemotherapy in first-line treatment was compared. The expression of programmed cell death ligand 1 (PD-L1) and tumor mutational burden (TMB) were evaluated. Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 was used to evaluate the efficacy, and Common Terminology Criteria for Adverse Events (CTCAE) version 4.03 was used to evaluate immune-related adverse. Kaplan-Meier and Log-rank test was performed. Cox regression was used in prognostic analysis.

RESULTS

Combined therapy acquired significantly higher overall response rate (ORR) compared with chemotherapy alone in elderly group (P<0.05), and also in younger group, despite the difference was not significant (P>0.05). The median progression-free survival (mPFS) and median overall survival (mOS) in elderly group were similar with younger group (P>0.05). Both combined group and immunology alone demonstrated prolonged mPFS in first-line compared with chemotherapy in elderly group. And combined group demonstrated significantly prolonged mPFS compared with chemotherapy in younger group (P<0.01). There was no difference of mOS between different regimes in two groups. Elderly LUSC patients had higher PD-L1 positive rate (≥1%) and similar TMB compared with younger group. There was no relationship between mPFS and mOS with the expression of PD-L1 and TMB. Immunology combined with chemotherapy demonstrated better mPFS compared to chemotherapy in first-line therapy with TMB-High (P<0.05), and inferior mPFS with TMB-Low despite the difference was not significant (P>0.05). Cox regression model demonstrated that clinical stage was an independent predictor and prognostic factor. The incidence of immune-related adverse was 58.0% (51/88) and grade 3 or above 25.0% (22/88). The most common grade 3 adverse events were rash, immune-associated pneumonia, and fatigue.

CONCLUSIONS

Immunology combined with chemotherapy increased ORR, mPFS and mOS of Chinese patients with LUSC in first-line therapy compared with chemotherapy. There was no difference of efficacy and adverse effects rate between elderly group and younger group. The adverse effects of immunology in elderly patients with LUSC were controllable.

TP53 and LRP1B Co-Wild Predicts Improved Survival for Patients with LUSC Receiving Anti-PD-L1 Immunotherapy

Immunotherapy brought long-term benefits for partial patients with lung squamous cell carcinoma (LUSC). The predictor of anti-PD-L1 therapy was controversial and limited in LUSC. We aimed to explore novel biomarker for LUSC immunotherapy and the potential mechanism. Five hundred and twenty-five Chinese patients (Geneplus cohort) with LUSC underwent targeted sequencing and were involved to explore the genomic profiling. TP53 and LRP1B were the most frequently recurrent genes and correlated to higher tumor mutational burden (TMB). We observed that LUSC patients with TP53 and LRP1B co-wild (co-wild type) were associated with better survival of anti-PD-L1 therapy compared with TP53 mutant or LRP1B mutant (mutant type) in POPAR/OAK cohort. Copy-number variation (CNV) and whole genome doubling (WGD) data from TCGA LUSC cohort were obtained to assess the CNV events. There were fewer CNV alterations and lower chromosome instability in patients with TP53/LRP1B co-wild compared with those with TP53/LRP1B mutant. RNA expression data from the TCGA LUSC cohort were collected to explore the differences in RNA expression and tumor immune microenvironment (TIME) between mutant and co-wild groups. The TP53/LRP1B co-wild type had a significantly increased proportion of multiple tumor-infiltrating lymphocytes (TILs), including activated CD8 T cell, activated dendritic cell (DC), and effector memory CD8 T cell. Immune-related gene sets including checkpoint, chemokine, immunostimulatory, MHC and receptors were enriched in the co-wild type. In conclusion, TP53/LRP1B co-wild LUSC conferred an elevated response rate in anti-PD-L1 therapy and improved survival, which was associated with a chromosome-stable phenotype and an activated immune microenvironment.

The efficacy and safety of albumin-bound paclitaxel plus carboplatin as neoadjuvant therapy for potentially resectable lung squamous cell carcinoma: a real-world retrospective cohort study

Background

In early and locally advanced stage non-small-cell lung cancer (NSCLC), surgery is the cornerstone of curative-intent treatments. And the addition of neoadjuvant or adjuvant chemotherapy can prolong overall survival (OS), albumin-bound paclitaxel plus carboplatin (ab-PC) as neoadjuvant therapy (NAT) has showed favorable effect for resectable lung squamous cell carcinoma (LSCC) with IIIA. However, to date, no study has investigated the efficacy of ab-PC as neoadjuvant chemotherapy in potentially resectable LSCC with IIIA–IIIB. This study aimed to evaluate the efficacy and safety of the regimen in potentially resectable LSCC.

Methods

Enrolled patients with stage IIIA and IIIB potentially resectable LSCC treated with neoadjuvant albumin-bound paclitaxel (nab-P; 100 mg/m², days 1, 8, and 15) and carboplatin (6 mg/mL/min, day 1) for two 21-day cycles at the Hunan Cancer Hospital between December 2017 and December 2019. The primary endpoint was the surgery conversion rate (SCR). Secondary endpoints included objective response rate (ORR), margin-free (R0) resection, major pathological response (mPR), and safety.

Results

In total, 49 patients were included in the study, with an overall response rate (ORR) of 67% (33/49). The SCR was 67% (33/49). Only 31 patients underwent surgery eventually, and R0 resection was achieved in 30 patients. Further, 4 (13%) and 11 (35%) of the 31 patients had a pathological complete response (pCR) and mPR, respectively. In total, 23 patients experienced treatment-related adverse events (TRAEs). The most common TRAE was liver disfunction (9 patients, 18%). Only 1 patient (2%) experienced a grade ≥3 TRAE of leukopenia. There were no treatment-related deaths or treatment discontinuations.

Conclusions

In this study, we found a high SCR (67%) and mPR (35%) after ab-PC treatment for stage IIIA and IIIB potentially resectable LSCC. ab-PC maybe considered a neoadjuvant chemotherapy option for potentially resectable LSCC patients.

The Anticancer Mechanisms of Scutellaria barbata against Lung Squamous Cell Carcinoma

Objective. Scutellaria barbata (S. barbata) is a Chinese traditional medicinal crop with anti-inflammatory as well as anticancer properties. To explore the anticancer mechanisms of functional monomers of S. barbata against lung squamous cell carcinoma (LUSC), a network pharmacology approach and molecular docking were utilized. Methods. The expression profile of genes encoding functional monomer components in S. barbata was obtained from the Traditional Chinese Medicine Systems Pharmacology platform (TCMSP) database. Expression data of LUSC-related genes were acquired from DisGeNET, GeneCards, OMIM, DrugBank, and TTD databases. The target genes of S. barbata that confer anticancer effects against LUSC were obtained by considering the intersecting genes between S. barbata target genes and LUSC-related genes. The potential regulatory pathways enriched in these intersected genes were identified using the KOBAS database, and Gene Ontology (GO) function enrichment analysis was performed using the online tool DAVID. The relationship network of S. barbata functional monomer components-action targets-disease-pathways was established using Cytoscape 3.8.2, and the protein-protein interaction network of those intersected genes was established using the STRING database. Finally, the hub genes were screened by using CytoNCA, a plug-in of Cytoscape, and hub gene expressions in LUSC were evaluated via the Gene Expression Profiling Interactive Analysis (GEPIA) database. AutoDockTools and PyMOL software were employed to verify the molecular docking on disease target proteins and drug functional molecules. Results. In S. barbata, 104 target genes and 20 hub genes encoding functional components against LUSC were screened out, six of which were significantly differentially expressed between LUSC samples and normal tissue samples in the GEPIA database. Here, GO analysis illustrated the involvement of these genes in the signal transduction and positive regulation of transcription from RNA polymerase II promoter and negative regulation of apoptosis, while KEGG pathway enrichment analysis demonstrated that these genes were mainly involved in several pathways, for instance, AGE-RAGE, PI3K-Akt, p53, and MAPK signaling pathway. There are four main functional components docking with six key target proteins, all of which have strong binding activity. Conclusions. We predicted the molecular mechanisms and signaling pathways of genes encoding functional components in S. barbata against LUSC. These discoveries offer novel understanding for further study, laying a scientific foundation for the production of synthetic monomer components of S. barbata.

Stratification of lung squamous cell carcinoma based on ferroptosis regulators: Potential for new therapeutic strategies involving ferroptosis induction

OBJECTIVES

Lung squamous cell carcinoma (LSCC) exhibits poor response to treatment compared with other lung cancer subtypes, resulting in worse prognosis. Therefore, new therapeutic strategies are required for advanced LSCC. Ferroptosis is a recently discovered nonapoptotic cell death caused by intracellular lipid peroxidation that can bring about effective cell death in cancer cells resistant to apoptosis. Hence, ferroptosis is a potential therapeutic strategy for refractory cancer.

MATERIALS AND METHODS

In this study, we performed clinicopathological and molecular analyses on tumor specimens from 270 patients with squamous cell lung cancer, focusing on the expression of glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1), which are known to be key regulators of ferroptosis, and the accumulation of 4-hydroxynoneral (4-HNE), a lipid peroxidation marker.

RESULTS

Immunohistochemistry revealed that patients with low 4-HNE accumulation and low levels of GPX4 or FSP1 had significantly worse prognoses than other patients (P = 0.001). This stratification was an independent prognostic predictor (P = 0.003). A dramatic cell death synergistic effect was observed on LSCC-derived LK-2 and EBC1 cells treated with GPX4 and FSP1 inhibitors. This effect was completely inhibited by treatment with the ferroptosis inhibitor. Notably, this was not the case in LK-2 cells treated with the apoptosis inhibitor, and in these cells, ferroptosis was induced.

CONCLUSION

Ferroptosis regulators GPX4 and FSP1 are associated with lung squamous cell cancer cancer's prognosis. We present the clinicopathological and molecular basis of novel therapeutic strategies for refractory LSCC.

DNA Methylation in Lung Cancer: Mechanisms and Associations with Histological Subtypes, Molecular Alterations, and Major Epidemiological Factors

Lung cancer is the major leading cause of cancer-related mortality worldwide. Multiple epigenetic factors-in particular, DNA methylation-have been associated with the development of lung cancer. In this review, we summarize the current knowledge on DNA methylation alterations in lung tumorigenesis, as well as their associations with different histological subtypes, common cancer driver gene mutations (e.g., KRAS, EGFR, and TP53), and major epidemiological risk factors (e.g., sex, smoking status, race/ethnicity). Understanding the mechanisms of DNA methylation regulation and their associations with various risk factors can provide further insights into carcinogenesis, and create future avenues for prevention and personalized treatments. In addition, we also highlight outstanding questions regarding DNA methylation in lung cancer to be elucidated in future studies.

The Role of Mitochondrial miRNAs in the Development of Radon-Induced Lung Cancer

MicroRNAs are short, non-coding RNA molecules regulating gene expression by inhibiting the translation of messenger RNA (mRNA) or leading to degradation. The miRNAs are encoded in the nuclear genome and exported to the cytosol. However, miRNAs have been found in mitochondria and are probably derived from mitochondrial DNA. These miRNAs are able to directly regulate mitochondrial genes and mitochondrial activity. Mitochondrial dysfunction is the cause of many diseases, including cancer. In this review, we consider the role of mitochondrial miRNAs in the pathogenesis of lung cancer with particular reference to radon exposure.

Ubiquitination-mediated molecular pathway alterations in human lung squamous cell carcinomas identified by quantitative ubiquitinomics

Abnormal ubiquitination is extensively associated with cancers. To investigate human lung cancer ubiquitination and its potential functions, quantitative ubiquitinomics was carried out between human lung squamous cell carcinoma (LSCC) and control tissues, which characterized a total of 627 ubiquitin-modified proteins (UPs) and 1209 ubiquitinated lysine sites. Those UPs were mainly involved in cell adhesion, signal transduction, and regulations of ribosome complex and proteasome complex. Thirty three UPs whose genes were also found in TCGA database were significantly related to overall survival of LSCC. Six significant networks and 234 hub molecules were obtained from the protein-protein interaction (PPI) analysis of those 627 UPs. KEGG pathway analysis of those UPs revealed 47 statistically significant pathways, and most of which were tumor-associated pathways such as mTOR, HIF-1, PI3K-Akt, and Ras signaling pathways, and intracellular protein turnover-related pathways such as ribosome complex, ubiquitin-mediated proteolysis, ER protein processing, and proteasome complex pathways. Further, the relationship analysis of ubiquitination and differentially expressed proteins shows that ubiquitination regulates two aspects of protein turnover - synthesis and degradation. This study provided the first profile of UPs and molecular networks in LSCC tissue, which is the important resource to insight into new mechanisms, and to identify new biomarkers and therapeutic targets/drugs to treat LSCC.

KLF5, a Novel Therapeutic Target in Squamous Cell Carcinoma

Squamous cell carcinomas (SCCs) are the most common ectodermal cancers, and result in more than 300,000 deaths per year. The Krüppel-like family of transcription factors play a critical role in cancer pathogenesis. The Krüppel-like factor 5 gene (KLF5), which is a member of Krüppel-like family, has been reported to promote cancer cell proliferation and tumorigenesis. In this review, we discuss the roles of KLF5 in different SCCs and the mechanisms by which KLF5 transcriptionally regulates its target gene expression in the pathogenesis and progression of SCCs. Due to its significant functions in cell proliferation and differentiation, KLF5 could be a novel diagnostic biomarker and therapeutic target for the treatment of SCCs.

Deregulation of AKT-mTOR Signaling Contributes to Chemoradiation Resistance in Lung Squamous Cell Carcinoma

Lung squamous cell carcinoma (LUSC) accounts for one of three of non-small cell lung carcinoma (NSCLC) and 30% of LUSC patients present with locally advanced, unresectable/medically inoperable disease, who are commonly treated with definitive chemoradiation. However, disease relapse in the radiation fields occurs in one of three cases. We aim to explore the underlying molecular mechanisms of chemoradiation resistance of LUSC. Patient-derived xenograft (PDX) models of LUSC were established in immunodeficient mice, followed by treatment with cisplatin in combination with clinically relevant courses of ionizing radiation (20, 30, and 40 Gy). The recurrent tumors were extracted for functional proteomics using reverse phase protein analysis (RPPA). We found that phospho-AKT-S473, phospho-AKT-T308, phospho-S6-S235/6, and phospho-GSK3β-S9 were upregulated in the chemoradiation-resistant 20 Gy + cisplatin and 40 Gy + cisplatin tumors compared with those in the control tumors. Ingenuity pathway analysis of the RPPA data revealed that AKT-mTOR signaling was the most activated signaling pathway in the chemoradiation-resistant tumors. Similarly, elevated AKT-mTOR signaling was observed in stable 40 Gy and 60 Gy resistant HARA cell lines compared with the parental cell line. Accordingly, pharmacologic inhibition of mTOR kinase by Torin2 significantly sensitized LUSC cell lines to ionizing radiation. In conclusion, using chemoradiation-resistant PDX models coupled with RPPA proteomics analysis, we revealed that deregulation of AKT-mTOR signaling may contribute to the chemoradiation resistance of LUSC. IMPLICATIONS: Clonal selection of subpopulations with high AKT-mTOR signaling in heterogeneous tumors may contribute to relapse of LUSC after chemoradiation. mTOR kinase inhibitors may be promising radiosensitizing agents in upfront treatment to prevent acquired resistance.

NTCU induced pre-malignant and malignant stages of lung squamous cell carcinoma in mice model

Mice have served as an excellent model to understand the etiology of lung cancer for years. However, data regarding dual-stage carcinogenesis of lung squamous cell carcinoma (SCC) remain elusive. Therefore, we aim to develop pre-malignant (PM) and malignant (M) lung SCC in vivo using N-nitroso-tris-chloroethylurea (NTCU). BALB/C mice were allotted into two main groups; PM and M groups which received treatment for 15 and 30 weeks, respectively. Then, the mice in each main group were allotted into three groups; control, vehicle, and cancer (n = 6), which received normal saline, 70% acetone, and 0.04 M NTCU by skin painting, respectively. Histopathologically, we discovered a mix of hyperplasia, metaplasia, and dysplasia lesions in the PM group and intracellular bridge; an SCC feature in the M group. The M group was positive for cytokeratin 5/6 protein which confirmed the lung SCC subtype. We also found significantly higher (P < 0.05) epithelium thickness in the cancer groups as compared to the vehicle and control groups at both the PM and M. Overall, this study discovered that NTCU is capable of developing PM and M lung SCC in mice model at appropriate weeks and the vehicle group was suggested to be adequate as control group for future research.

Titin Mutation Is Associated With Tumor Mutation Burden and Promotes Antitumor Immunity in Lung Squamous Cell Carcinoma

Lung squamous cell carcinoma (LUSC) is a leading cause of mobidity and mortality worldwide. Recently, there was a shift in the treatment pattern of immune therapy in LUSC patients; merely a small number of patients with non-small cell lung cancer (NSCLC) at advanced stages respond well to immune checkpoint blockade (ICB) therapy, and tumor mutation burden (TMB) is a valuable independent indicator of response to immune therapy. However, specific gene mutations and their relationship with TMB and tumor-infiltrating immunocytes in LUSC are still unclear. In the present paper, our team analyzed the somatically mutated genes from the ICGC (International Cancer Genome Consortium) and TCGA (The Cancer Genome Atlas) datasets and discovered that 15 frequent gene mutations occurred in both cohorts, including ZFHX4, MUC16, FLG, TP53, LRP1B, TTN, SYNE1, RYR2, CSMD3, USH2A, MUC17, DNAH5, FAM135B, COL11A1, and RYR3. Interestingly, only mutated TTN was related to higher TMB and prognostic outcomes among the 15 mutated genes. Moreover, according to the CIBERSORT algorithm, we revealed that TTN mutation enhanced the antitumor immune response. In conclusion, TTN may have important clinical implications for relevant immune therapy of lung squamous carcinoma.

Expression of oncogenic long noncoding RNA PSMG3-antisense 1 in lung squamous cell carcinoma

Lung squamous cell carcinoma (LUSC) is one of the most common subtypes of lung cancer that accounts for ~50% of all lung cancer cases. Long noncoding RNA (lncRNA) PSMG3-antisense (AS) 1 has been suggested to play an important role in various types of cancer. Therefore, the aim of the present study was to investigate the role of PSMG3-AS1 using clinical specimens and data from 130 patients with LUSC. The expression levels of PSMG3-AS1 and miR-143-3p were detected in LUSC specimens, and the correlation between lncRNA PSMG3-AS1 expression and patient clinical characteristics was analyzed. Cell Counting Kit-8, Transwell migration and invasion assays were used to investigate the functional role of PSMG3-AS1 in LUSC. The mechanism of PSMG3-AS1 on LUSC cells was also investigated using a luciferase activity assay with wild-type or mutated PSMG3-AS1. PSMG3-AS1 was found to be upregulated in LUSC, and high expression was associated with positive lymph node metastasis and a higher TNM stage. The results of multivariate Cox regression analysis revealed that PSMG3-AS1 may serve as an independent prognostic indicator in LUSC. Furthermore, inhibiting PSMG3-AS1 expression reduced tumor cell proliferative, migratory and invasive abilities. Moreover, PSMG3-AS1 was found to be closely associated with miR-143-3p in LUSC, and thus may become a potential prognostic marker and therapeutic target for the treatment of LUSC in the future.

Protein co-expression network-based profiles revealed from laser-microdissected cancerous cells of lung squamous-cell carcinomas

No therapeutic targets have been identified for lung squamous cell cancer (SqCC) which is the second most prevalent lung cancer because its molecular profiles remain unclear. This study aimed to unveil disease-related protein networks by proteomic and bioinformatic assessment of laser-microdissected cancerous cells from seven SqCCs compared with eight representative lung adenocarcinomas. We identified three network modules significant to lung SqCC using weighted gene co-expression network analysis. One module was intrinsically annotated to keratinization and cell proliferation of SqCC, accompanied by hypoxia-induced aerobic glycolysis, in which key regulators were activated (HIF1A, ROCK2, EFNA1-5) and highly suppressed (KMT2D). The other two modules were significant for translational initiation, nonsense-mediated mRNA decay, inhibited cell death, and interestingly, eIF2 signaling, in which key regulators, MYC and MLXIPL, were highly activated. Another key regulator LARP1, the master regulator in cap-dependent translation, was highly suppressed although upregulations were observed for hub proteins including EIF3F and LARP1 targeted ribosomal proteins, among which PS25 is the key ribosomal protein in IRES-dependent translation. Our results suggest an underlying progression mechanism largely caused by switching to the cap-independent, IRES-dependent translation of mRNA subsets encoding oncogenic proteins. Our findings may help to develop therapeutic strategies to improve patient outcomes.

USP28 deletion and small-molecule inhibition destabilizes c-MYC and elicits regression of squamous cell lung carcinoma

Lung squamous cell carcinoma (LSCC) is a considerable global health burden, with an incidence of over 600,000 cases per year. Treatment options are limited, and patient’s 5-year survival rate is less than 5%. The ubiquitin-specific protease 28 (USP28) has been implicated in tumourigenesis through its stabilization of the oncoproteins c-MYC, c-JUN, and Δp63. Here, we show that genetic inactivation of Usp28-induced regression of established murine LSCC lung tumours. We developed a small molecule that inhibits USP28 activity in the low nanomole range. While displaying cross-reactivity against the closest homologue USP25, this inhibitor showed a high degree of selectivity over other deubiquitinases. USP28 inhibitor treatment resulted in a dramatic decrease in c-MYC, c-JUN, and Δp63 proteins levels and consequently induced substantial regression of autochthonous murine LSCC tumours and human LSCC xenografts, thereby phenocopying the effect observed by genetic deletion. Thus, USP28 may represent a promising therapeutic target for the treatment of squamous cell lung carcinoma.

The prognostic landscape of genes and infiltrating immune cells in cytokine induced killer cell treated-lung squamous cell carcinoma and adenocarcinoma

OBJECTIVE

Patients with non-small cell lung cancer (NSCLC) respond differently to cytokine-induced killer cell (CIK) treatment. Therefore, potential prognostic markers to identify patients who would benefit from CIK treatment must be elucidated. The current research aimed at identifying predictive prognostic markers for efficient CIK treatment of patients with NSCLC.

METHODS

Patients histologically diagnosed with NSCLC were enrolled from the Tianjin Medical University Cancer Institute and Hospital. We performed whole-exome sequencing (WES) on the tumor tissues and paired adjacent benign tissues collected from 50 patients with NSCLC, and RNA-seq on tumor tissues of 17 patients with NSCLC before CIK immunotherapy treatment. Multivariate Cox proportional hazard regression analysis was used to analyze the association between clinical parameters and prognostic relevance. WES and RNA-seq data between lung squamous cell carcinoma (SCC) and adenocarcinoma (Aden) were analyzed and compared.

RESULTS

The pathology subtype of lung cancer was the most significantly relevant clinical parameter associated with DFS, as analyzed by multivariate Cox proportional hazard regression (P = 0.031). The patients with lung SCC showed better CIK treatment efficacy and extended DFS after CIK treatment. Relatively low expression of HLA class II genes and checkpoint molecules, and less immunosuppressive immune cell infiltration were identified in the patients with lung SCC.

CONCLUSIONS

Coordinated suppression of the expression of HLA class II genes and checkpoint molecules, as well as less immune suppressive cell infiltration together contributed to the better CIK treatment efficacy in lung SCC than lung Aden.

Identification of JAK2 and FOXM1 expression as novel candidate biomarkers for predicting the benefit of immunotherapy in lung squamous cell carcinoma

Background

Lung squamous cell carcinoma (LUSC) accounts for about 30% of all non-small cell lung cancers (NSCLC). However, only a small percentage of LUSC patients gain benefit from immune checkpoint inhibitors (ICIs).

Methods

This study analyzed LUSC patients from The Cancer Genome Atlas (TCGA), which were divided into 2 groups: PD-L1 high-expression/TMB-high (TPH) and PD-L1 low-expression/TMB-low (TPL) group based on programmed death-ligand 1 (PD-L1) expression and tumor mutational burden (TMB) status. The differences in tumor-infiltrating immune cells were estimated between the 2 groups. The overlap of differentially expressed genes and proteins (DEGs and DEPs) between 2 groups were used as candidate biomarkers. Kaplan-Meier curves were used to evaluate the association between risk score and overall survival (OS).

Results

More abundant immune infiltration fractions were found in TPH group. Janus kinase 2 (JAK2) and forkhead box protein M1 (FOXM1) were identified as DEGs between the TPH and TPL groups. Subsequently, we developed a risk score that combined the expression of JAK2 and FOXM1 in an effort to accurately determine the survival risk of LUSC patients. Patients with high-risk [hazard ratio (HR), median OS, 43.1 months 1.924; 95% confidence interval (CI): 1.256 to 2.945; P=0.002) had shorter survival than those with low-risk (median OS, 70.0 months). External data verification found that JAK2 and FOXM1 were significantly expressed at a higher level in the responders receiving immunotherapy (P=0.038 and P=0.009, respectively).

Conclusions

The expressions of JAK2 and FOXM1 can be used as novel candidate biomarkers for predicting the benefit of immunotherapy in LUSC.

PD-L1 Protein Expression and Gene Amplification Correlate with the Clinicopathological Characteristics and Prognosis of Lung Squamous Cell Carcinoma

Purpose

To investigate PD-L1 protein expression and gene amplification in lung squamous cell carcinoma (LUSC) and analyse their correlation with the clinicopathological characteristics and prognosis of LUSC patients.

Patients and Methods

Tissue samples from 164 LUSC patients were collected. PD-L1 protein was detected by immunochemistry (IHC), and PD-L1 gene amplification was investigated by fluorescence in situ hybridization in LUSC patients.

Results

The positive expression rate of PD-L1 in LUSC was 47.6% (78/164), and the amplification rate of PD-L1 was 6.7% (11/164); both rates were higher than those of paratumor tissue. Both PD-L1 positive expression and gene amplification were correlated with clinical stage and lymph node metastasis (P<0.05). PD-L1 protein expression, PD-L1 gene amplification, late stage, lymph node metastasis and distant metastasis were significantly correlated with the prognosis of patients. Among these factors, late stage, lymph node metastasis, PD-L1 protein expression and PD-L1 gene amplification were independent prognostic factors for LUSC.

Conclusion

Positive PD-L1 protein expression and gene amplification are involved in the malignant progression and metastasis of LUSC. Both PD-L1 protein expression and gene amplification are associated with poor prognosis.

The Past, Present, and Future (Liquid Biopsy) of Serum Tumor Markers in Lung Cancer: A Primer for the Radiologist

ABSTRACT

Lung cancer continues to be a major cause of death throughout the world. The ability to both accurately diagnose lung cancer in its early stages and monitor response to treatment is essential to reducing the morbidity and mortality associated with the disease. Serum tumor markers have been identified as potential biomarkers that may aid in lung cancer diagnosis and surveillance. These markers, when combined with cross-sectional imaging, may result in more robust screening and surveillance protocols. The future role of serum tumor markers in lung cancer includes the advancement of "liquid biopsies," in which peripheral blood samples are analyzed for tumor components without the need for a tissue biopsy.

Role of NRF2 in Lung Cancer

The gene expression program induced by NRF2 transcription factor plays a critical role in cell defense responses against a broad variety of cellular stresses, most importantly oxidative stress. NRF2 stability is fine-tuned regulated by KEAP1, which drives its degradation in the absence of oxidative stress. In the context of cancer, NRF2 cytoprotective functions were initially linked to anti-oncogenic properties. However, in the last few decades, growing evidence indicates that NRF2 acts as a tumor driver, inducing metastasis and resistance to chemotherapy. Constitutive activation of NRF2 has been found to be frequent in several tumors, including some lung cancer sub-types and it has been associated to the maintenance of a malignant cell phenotype. This apparently contradictory effect of the NRF2/KEAP1 signaling pathway in cancer (cell protection against cancer versus pro-tumoral properties) has generated a great controversy about its functions in this disease. In this review, we will describe the molecular mechanism regulating this signaling pathway in physiological conditions and summarize the most important findings related to the role of NRF2/KEAP1 in lung cancer. The focus will be placed on NRF2 activation mechanisms, the implication of those in lung cancer progression and current therapeutic strategies directed at blocking NRF2 action.

The METTL3-m6A Epitranscriptome: Dynamic Regulator of Epithelial Development, Differentiation, and Cancer

Dynamic modifications on RNA, frequently termed both, “RNA epigenetics” and “epitranscriptomics”, offer one of the most exciting emerging areas of gene regulation and biomedicine. Similar to chromatin-based epigenetic mechanisms, writers, readers, and erasers regulate both the presence and interpretation of these modifications, thereby adding further nuance to the control of gene expression. In particular, the most abundant modification on mRNAs, N⁶-methyladenosine (m⁶A), catalyzed by methyltransferase-like 3 (METTL3) has been shown to play a critical role in self-renewing somatic epithelia, fine-tuning the balance between development, differentiation, and cancer, particularly in the case of squamous cell carcinomas (SCCs), which in aggregate, outnumber all other human cancers. Along with the development of targeted inhibitors of epitranscriptomic modulators (e.g., METTL3) now entering clinical trials, the field holds significant promise for treating these abundant cancers. Here, we present the most current summary of this work, while also highlighting the therapeutic potential of these discoveries.

Toward comprehensive functional analysis of gene lists weighted by gene essentiality scores

MOTIVATION

Gene functional enrichment analysis represents one of the most popular bioinformatics methods for annotating the pathways and function categories of a given gene list. Current algorithms for enrichment computation such as Fisher's exact test and hypergeometric test totally depend on the category count numbers of the gene list and one gene set. In this case, whatever the genes are, they were treated equally. However, actually genes show different scores in their essentiality in a gene list and in a gene set. It is thus hypothesized that the essentiality scores could be important and should be considered in gene functional analysis.

RESULTS

For this purpose, here we proposed WEAT (https://www.cuilab.cn/weat/), a weighted gene set enrichment algorithm and online tool by weighting genes using essentiality scores. We confirmed the usefulness of WEAT using three case studies, the functional analysis of one aging-related gene list, one gene list involved in Lung Squamous Cell Carcinoma (LUSC), and one cardiomyopathy gene list from Drosophila model. Finally, we believe that the WEAT method and tool could provide more possibilities for further exploring the functions of given gene lists.

AVAILABILITY

The datasets generated and analyzed during the current study are available on our website at https://www.cuilab.cn/weat/.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Gene expression profiles of the original tumors influence the generation of PDX models of lung squamous cell carcinoma

Patient-derived xenograft (PDX) murine models are employed for preclinical research on cancers, including non-small cell lung cancers (NSCLCs). Even though lung squamous cell carcinomas (LUSCs) show the highest engraftment rate among NSCLCs, half of them nevertheless show PDX failure in immunodeficient mice. Here, using immunohistochemistry and RNA sequencing, we evaluated the distinct immunohistochemical and gene expression profiles of resected LUSCs that showed successful engraftment. Among various LUSCs, including the basal, classical, secretory, and primitive subtypes, those in the non-engrafting (NEG) group showed gene expression profiles similar to the pure secretory subtype with positivity for CK7, whereas those in the engrafting (EG) group were similar to the mixed secretory subtype with positivity for p63. Pathway analysis of 295 genes that demonstrated significant differences in expression between NEG and EG tumors revealed that the former had enriched expression of genes related to the immune system, whereas the latter had enriched expression of genes related to the cell cycle and DNA replication. Interestingly, NEG tumors showed higher infiltration of B cells (CD19+) and follicular dendritic cells (CD23+) in lymph follicles than EG tumors. Taken together, these findings suggest that the PDX cancer model of LUSC represents only a certain population of LUSCs and that CD19- and CD23-positive tumor-infiltrating immune cells in the original tumors may negatively influence PDX engraftment in immunodeficient mice.

Molecular characterization of lung squamous cell carcinoma tumors reveals therapeutically relevant alterations

INTRODUCTION

Unlike lung adenocarcinoma patients, there is no FDA-approved targeted-therapy likely to benefit lung squamous cell carcinoma patients.

MATERIALS AND METHODS

We performed survival analyses of lung squamous cell carcinoma patients harboring therapeutically relevant alterations identified by whole exome sequencing and mass spectrometry-based validation across 430 lung squamous tumors.

RESULTS

We report a mean of 11.6 mutations/Mb with a characteristic smoking signature along with mutations in TP53 (65%), CDKN2A (20%), NFE2L2 (20%), FAT1 (15%), KMT2C (15%), LRP1B (15%), FGFR1 (14%), PTEN (10%) and PREX2 (5%) among lung squamous cell carcinoma patients of Indian descent. In addition, therapeutically relevant EGFR mutations occur in 5.8% patients, significantly higher than as reported among Caucasians. In overall, our data suggests 13.5% lung squamous patients harboring druggable mutations have lower median overall survival, and 19% patients with a mutation in at least one gene, known to be associated with cancer, result in significantly shorter median overall survival compared to those without mutations.

CONCLUSIONS

We present the first comprehensive landscape of genetic alterations underlying Indian lung squamous cell carcinoma patients and identify EGFR, PIK3CA, KRAS and FGFR1 as potentially important therapeutic and prognostic target.

Novel gene signatures for stage classification of the squamous cell carcinoma of the lung

The squamous cell carcinoma of the lung (SCLC) is one of the most common types of lung cancer. As GLOBOCAN reported in 2018, lung cancer was the first cause of death and new cases by cancer worldwide. Typically, diagnosis is made in the later stages of the disease with few treatment options available. The goal of this work was to find some key components underlying each stage of the disease, to help in the classification of tumor samples, and to increase the available options for experimental assays and molecular targets that could be used in treatment development. We employed two approaches. The first was based in the classic method of differential gene expression analysis, network analysis, and a novel concept known as network gatekeepers. The second approach was using machine learning algorithms. From our combined approach, we identified two sets of genes that could function as a signature to identify each stage of the cancer pathology. We also arrived at a network of 55 nodes, which according to their biological functions, they can be regarded as drivers in this cancer. Although biological experiments are necessary for their validation, we proposed that all these genes could be used for cancer development treatments.

TNIK Is a Therapeutic Target in Lung Squamous Cell Carcinoma and Regulates FAK Activation through Merlin

Lung squamous cell carcinoma (LSCC) is the second most prevalent type of lung cancer. Despite extensive genomic characterization, no targeted therapies are approved for the treatment of LSCC. Distal amplification of the 3q chromosome is the most frequent genomic alteration in LSCC, and there is an urgent need to identify efficacious druggable targets within this amplicon. We identify the protein kinase TNIK as a therapeutic target in LSCC. TNIK is amplified in approximately 50% of LSCC cases. TNIK genetic depletion or pharmacologic inhibition reduces the growth of LSCC cells in vitro and in vivo. In addition, TNIK inhibition showed antitumor activity and increased apoptosis in established LSCC patient-derived xenografts. Mechanistically, we identified the tumor suppressor Merlin/NF2 as a novel TNIK substrate and showed that TNIK and Merlin are required for the activation of focal adhesion kinase. In conclusion, our data identify targeting TNIK as a potential therapeutic strategy in LSCC. SIGNIFICANCE: Targeted therapies have not yet been approved for the treatment of LSCC, due to lack of identification of actionable cancer drivers. We define TNIK catalytic activity as essential for maintaining LSCC viability and validate the antitumor efficacy of TNIK inhibition in preclinical models of LSCC.This article is highlighted in the In This Issue feature, p. 1307.

Genotyping Squamous Cell Lung Carcinoma in Colombia (Geno1.1-CLICaP)

Background

Lung cancer is a public health problem, and squamous cell carcinoma (SCC) is the second most prevalent subtype of this neoplasm. Compared to other subtypes, including adenocarcinoma, SCC is less well understood in terms of molecular pathogenesis, limiting therapeutic options among targeted agents approved for other disease subgroups. In this study, we sought to characterize the SCC genomic profile using a validated Next Generation Sequencing (NGS) platform.

Methods

The comprehensive NGS assay (TruSight Tumor 170) was used in order to target the full coding regions of 170 cancer-related genes on SCC samples. PD-L1 expression in tumor cells (TCs) was assessed using clone 22C3 (Dako). Clinical outcomes were correlated with molecular profile, including progression free survival (PFS), overall response rate (ORR), and overall survival (OS).

Results

A total of 26 samples were included, median age was 67 years (r, 33–83) and 53.8% were men. Tobacco consumption was identified in all subjects (mean 34-year package). For first-line treatment 80.8% of patients received cisplatin or carboplatin plus gemcitabine. In terms of molecular profile, we identified a high prevalence of inactivating mutations in TP53 (61.5%), PIK3CA (34.6%), MLL2 (34.6%), KEAP1 (38.4%), and NOTCH1 (26.9%). PD-L1 expression ranged from negative, 1, 2–49, and ≥50% in 23.1, 38.5, 26.9, and 11.5%, respectively. Interestingly, the genetic alterations did not have an effect in PFS, OS or ORR in this study. However, PDL1 expression was higher among those who had mutations in TP53 (p = 0.037) and greater expression of PDL1 was related to PIK3CA alterations (p = 0.05).

Conclusions

The genomic profile of SCC encompasses important genes including TP53, PIK3CA and KEAP1. TP53 mutations could be associated with PDL1 expression, generating hypothesis regarding specific treatment options.

Utilization of circulating cell-free DNA profiling to guide first-line chemotherapy in advanced lung squamous cell carcinoma

Rationale: Platinum-based chemotherapy is one of treatment mainstay for patients with advanced lung squamous cell carcinoma (LUSC) but it is still a "one-size fits all" approach. Here, we aimed to investigate the predictive and monitoring role of circulating cell-free DNA (cfDNA) profiling for the outcome of first-line chemotherapy in patients with advanced LUSC. Methods: Peripheral blood samples of 155 patients from a phase IV trial and 42 cases from an external real-world cohort were prospectively collected. We generated a copy number variations-based classifier via machine learning algorithm to integrate molecular profiling of cfDNA, named RESPONSE SCORE (RS) to predict the treatment outcome. To monitor the treatment efficacy, cfDNA samples collected at different time points were subjected to an ultra-deep sequencing platform. Results: The results showed that patients with high RS showed substantially higher objective response rate than those with low RS in training set (P < 0.001), validation set (P < 0.001) and real-world cohort (P = 0.019). Furthermore, a significant difference was observed in both progression-free survival (training set, P < 0.001; validation set: P < 0.001; real-world cohort: P = 0.019) and overall survival (training set, P < 0.001; validation set: P = 0.037) between high and low RS group. Notably, variant allele frequency (VAF) calculated from an ultra-deep sequencing platform significantly reduced in patients experienced a complete or partial response after 2 cycles of chemotherapy (P < 0.001), while it significantly increased in these of non-responder (P < 0.001). Moreover, VAF undetectable after 2 cycles of chemotherapy was correlated with markedly better objective response rate (P < 0.001) and progression-free survival (P < 0.001) than those with detectable VAF. Conclusions: These findings indicated that the RS, a circulating cfDNA sequencing-based stratification index, could help to guide first-line chemotherapy in advanced LUSC. The change of VAF is valuable to monitor the treatment response.