Anti-PD1/PD-L1 Immunotherapy for Non-Small Cell Lung Cancer with Actionable Oncogenic Driver Mutations

Anti-PD1/PD-L1 immunotherapy has emerged as a standard of care for stage III-IV non-small cell lung cancer (NSCLC) over the past decade. Patient selection is usually based on PD-L1 expression by tumor cells and/or tumor mutational burden. However, mutations in oncogenic drivers such as EGFR, ALK, BRAF, or MET modify the immune tumor microenvironment and may promote anti-PD1/PD-L1 resistance. In this review, we discuss the molecular mechanisms associated with these mutations, which shape the immune tumor microenvironment and may impede anti-PD1/PD-L1 efficacy. We provide an overview of the current clinical data on anti-PD1/PD-L1 efficacy in NSCLC with oncogenic driver mutation.     

L-Type Amino Acid Transporter 1 Regulates Cancer Stemness and the Expression of Programmed Cell Death 1 Ligand 1 in Lung Cancer Cells

The l-type amino acid transporter 1 (LAT1) is a membranous transporter that transports neutral amino acids for cells and is dysregulated in various types of cancer. Here, we first observed increased LAT1 expression in pemetrexed-resistant non-small cell lung cancer (NSCLC) cells with high cancer stem cell (CSC) activity, and its mRNA expression level was associated with shorter overall survival in the lung adenocarcinoma dataset of the Cancer Genome Atlas database. The inhibition of LAT1 by a small molecule inhibitor, JPH203, or by RNA interference led to a significant reduction in tumorsphere formation and the downregulation of several cancer stemness genes in NSCLC cells through decreased AKT serine/threonine kinase (AKT)/mammalian target of rapamycin (mTOR) activation. The treatment of the cell-permeable leucine derivative promoted AKT/mTOR phosphorylation and reversed the inhibitory effect of JPH203 in the reduction of CSC activity in pemetrexed-resistant lung cancer cells. Furthermore, we observed that LAT1 silencing caused the downregulation of programmed cell death 1 ligand 1 (PD-L1) on lung cancer cells. The PD-L1⁺/LAT1⁺ subpopulation of NSCLC cells displayed great CSC activity with increased expression of several cancer stemness genes. These data suggest that LAT1 inhibitors can serve as anti-CSC agents and could be used in combination with immune checkpoint inhibitors in lung cancer therapy.     

Fascaplysin Induces Apoptosis and Ferroptosis,and Enhances Anti-PD-1 Immunotherapy in Non-Small Cell Lung Cancer (NSCLC) by Promoting PD-L1 Expression

Fascaplysin is a natural product isolated from sponges with a wide range of anticancer activities. However, the mechanism of fascaplysin against NSCLC has not been clearly studied. In this study, fascaplysin was found to inhibit migration by regulating the wnt/β-catenin signaling pathway and reversing the epithelial–mesenchymal transition phenotype. Further research showed that the anti-NSCLC effect of fascaplysin was mainly through the induction of ferroptosis and apoptosis. Fascaplysin-induced ferroptosis in lung cancer cells, evidenced by increased levels of ROS and Fe²⁺ and downregulation of ferroptosis-associated protein and endoplasmic reticulum stress, was involved in fascaplysin-induced ferroptosis. In addition, ROS was found to mediate fascaplysin-induced apoptosis. Fascaplysin significantly upregulated the expression of PD-L1 in lung cancer cells, and enhanced anti-PD-1 antitumor efficacy in a syngeneic mouse model. Therefore, these results suggest that fascaplysin exerts anticancer effects by inducing apoptosis and ferroptosis in vitro, and improving the sensitivity of anti-PD-1 immunotherapy in vivo. Fascaplysin is a promising compound for the treatment of NSCLC.     

Current Immunotherapeutic Strategies Targeting the PD-1/PD-L1 Axis in Non-Small Cell Lung Cancer with Oncogenic Driver Mutations

Treatment strategies targeting programed cell death 1 (PD-1) or its ligand, PD-L1, have been developed as immunotherapy against tumor progression for various cancer types including non-small cell lung cancer (NSCLC). The recent pivotal clinical trials of immune-checkpoint inhibiters (ICIs) combined with cytotoxic chemotherapy have reshaped therapeutic strategies and established various first-line standard treatments. The therapeutic effects of ICIs in these clinical trials were analyzed according to PD-L1 tumor proportion scores or tumor mutational burden; however, these indicators are insufficient to predict the clinical outcome. Consequently, molecular biological approaches, including multi-omics analyses, have addressed other mechanisms of cancer immune escape and have revealed an association of NSCLC containing specific driver mutations with distinct immune phenotypes. NSCLC has been characterized by driver mutation-defined molecular subsets and the effect of driver mutations on the regulatory mechanism of PD-L1 expression on the tumor itself. In this review, we summarize the results of recent clinical trials of ICIs in advanced NSCLC and the association between driver alterations and distinct immune phenotypes. We further discuss the current clinical issues with a future perspective for the role of precision medicine in NSCLC.     

Targeting SPHK1/PBX1 Axis Induced Cell Cycle Arrest in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) accounts for 85~90% of lung cancer cases, with a poor prognosis and a low 5-year survival rate. Sphingosine kinase-1 (SPHK1), a key enzyme in regulating sphingolipid metabolism, has been reported to be involved in the development of NSCLC, although the underlying mechanism remains unclear. In the present study, we demonstrated the abnormal signature of SPHK1 in NSCLC lesions and cell lines of lung cancers with a potential tumorigenic role in cell cycle regulation. Functionally, ectopic Pre-B cell leukemia homeobox-1 (PBX1) was capable of restoring the arrested G1 phase induced by SPHK1 knockdown. However, exogenous sphingosine-1-phosphate (S1P) supply had little impact on the cell cycle arrest by PBX1 silence. Furthermore, S1P receptor S1PR3 was revealed as a specific switch to transport the extracellular S1P signal into cells, and subsequently activated PBX1 to regulate cell cycle progression. In addition, Akt signaling partially participated in the SPHK1/S1PR3/PBX1 axis to regulate the cell cycle, and the Akt inhibitor significantly decreased PBX1 expression and induced G1 arrest. Targeting SPHK1 with PF-543 significantly inhibited the cell cycle and tumor growth in preclinical xenograft tumor models of NSCLC. Taken together, our findings exhibit the vital role of the SPHK1/S1PR3/PBX1 axis in regulating the cell cycle of NSCLC, and targeting SPHK1 may develop a therapeutic effect in tumor treatment.     

EGFR-Mutated Non-Small Cell Lung Cancer and Resistance to Immunotherapy: Role of the Tumor Microenvironment

Lung cancer is a leading cause of cancer-related deaths worldwide. About 10–30% of patients with non-small cell lung cancer (NSCLC) harbor mutations of the EGFR gene. The Tumor Microenvironment (TME) of patients with NSCLC harboring EGFR mutations displays peculiar characteristics and may modulate the antitumor immune response. EGFR activation increases PD-L1 expression in tumor cells, inducing T cell apoptosis and immune escape. EGFR-Tyrosine Kinase Inhibitors (TKIs) strengthen MHC class I and II antigen presentation in response to IFN-γ, boost CD8+ T-cells levels and DCs, eliminate FOXP3+ Tregs, inhibit macrophage polarization into the M2 phenotype, and decrease PD-L1 expression in cancer cells. Thus, targeted therapy blocks specific signaling pathways, whereas immunotherapy stimulates the immune system to attack tumor cells evading immune surveillance. A combination of TKIs and immunotherapy may have suboptimal synergistic effects. However, data are controversial because activated EGFR signaling allows NSCLC cells to use multiple strategies to create an immunosuppressive TME, including recruitment of Tumor-Associated Macrophages and Tregs and the production of inhibitory cytokines and metabolites. Therefore, these mechanisms should be characterized and targeted by a combined pharmacological approach that also concerns disease stage, cancer-related inflammation with related systemic symptoms, and the general status of the patients to overcome the single-drug resistance development.     

Morphologic-Molecular Transformation of Oncogene Addicted Non-Small Cell Lung Cancer

Patients with non-small cell lung cancer, especially adenocarcinomas, harbour at least one oncogenic driver mutation that can potentially be a target for therapy. Treatments of these oncogene-addicted tumours, such as the use of tyrosine kinase inhibitors (TKIs) of mutated epidermal growth factor receptor, have dramatically improved the outcome of patients. However, some patients may acquire resistance to treatment early on after starting a targeted therapy. Transformations to other histotypes—small cell lung carcinoma, large cell neuroendocrine carcinoma, squamous cell carcinoma, and sarcomatoid carcinoma—have been increasingly recognised as important mechanisms of resistance and are increasingly becoming a topic of interest for all specialists involved in the diagnosis, management, and care of these patients. This article, after examining the most used TKI agents and their main biological activities, discusses histological and molecular transformations with an up-to-date review of all previous cases published in the field. Liquid biopsy and future research directions are also briefly discussed to offer the reader a complete and up-to-date overview of the topic.     

Proteomic Analysis Identified DJ-1 as a Cisplatin Resistant Marker in Non-Small Cell Lung Cancer

The aim of study is to identify cisplatin-resistance associated biomarkers for non-small cell lung cancers (NSCLC). We use two-dimensional electrophoresis (2-DE) combined with MALDI-TOF mass spectrometry to compare the proteome between lung cancer cell line A549 and its cisplatin-resistant subline A549/DDP. Nine cisplatin resistance-related proteins were identified, and DJ-1, one of the differently expressed proteins, was selected for further validation and evaluation. Immunohistochemical results demonstrated that high expression level of DJ-1 was associated with cisplatin resistance and a predictor for poor prognosis in 67 locally advanced NSCLC patients. Furthermore, in vitro results showed that silencing DJ-1 increased the proliferation inhibitory effect of cisplatin to A549/DDP cells. In conclusion, DJ-1 might play an important role in the resistibility to cisplatin, and it could also act as a novel candidate biomarker for predicting the response of NSCLC patients to cisplatin-based chemotherapy.     

Expression of the MT1 Melatonin Receptor in Ovarian Cancer Cells

Ovarian cancer (OC) is the leading cause of death among women with genital tract disorders. Melatonin exhibits oncostatic properties which it may effect through binding to its membrane receptor, MT1. The aim of this study was to determine the expression of MT1 in OC cells and to correlate this with clinical and pathological data. Immunohistochemistry was performed on 84 cases of OC. Normal ovarian epithelial (IOSE 364) and OC (SK-OV-3, OVCAR-3) cell lines were used to examine the MT1 expression at protein level using the western blot and immunofluorescence technique. The expression of MT1 was observed as cytoplasmic-membrane (MT1_CM) and membrane (MT1_M) reactions. A positive correlation between MT1_CM and MT1_M was found in all the studied cases. There were no significant differences between the expression of MT1_CM, MT1_M, and histological type, staging, grading, presence of residual disease, or overall survival time. Immunofluorescence showed both MT1_M and MT1_CM expression in all the tested cell lines. Western blot illustrated the highest protein level of MT1 in IOSE 364 and the lowest in the OVCAR-3. The results indicate the limited prognostic significance of MT1 in OC cells.     

肺癌抑癌基因1对鼻咽癌细胞株HNE-1增殖与侵袭能力的影响

目的探讨肺癌抑癌基因1(Tumor suppressor in lung cancer 1,TSLC1)对鼻咽癌细胞株HNE-1增殖与侵袭能力的影响。方法采用RT-PCR法从乳腺癌细胞株MCF-7中扩增TSLC1基因全长编码区序列,构建重组真核表达质粒pcDNA3.1-TSLC1,转染HNE-1细胞,RT-PCR及Western blot检测TSLC1基因mRNA和蛋白的表达水平。MTT和Transwell小室试验检测TSLC1基因过表达对HNE-1细胞增殖及侵袭能力的影响。结果重组表达质粒pcDNA3.1-TSLC1经双酶切及测序证明构建正确;稳定转染重组表达质粒的HNE-1细胞中TSLC1基因出现过表达;TSLC1基因过表达可显著抑制HNE-1细胞的增殖与侵袭能力。结论 TSLC1基因过表达对HNE-1细胞增殖与侵袭能力具有明显的抑制作用,为鼻咽癌的基因治疗提供了理想的分子靶点。     

Cell Penetrating Peptide-Based Self-Assembly for PD-L1 Targeted Tumor Regression

Cell penetrating peptides (CPPs) are peptides that can directly adapt to cell membranes and then permeate into cells. CPPs are usually covalently linked to the surface of nanocarriers to endow their permeability to the whole system. However, hybrids with lipids or polymers make the metabolism much more sophisticated and even more difficult to determine. In this study, we present a continuous sequence of 18 amino acids (FFAARTMIWY(d-P)GAWYKRI). It forms nanospheres around 170 nm, which increase slightly after loading with siRNA and DOX. Notably, it can be internalized by cancer cells mainly through electronic interactions and PD-L1-mediated endocytosis. Compared with poly-l-lysine and polyethyleneimine, it has a much higher efficiency (about four times) of gene transduction while lowering toxicity. In the treatment of cancer, it causes apoptosis (21%) and inhibits the expression of SURVIVIN protein in vitro. In vivo, it shows good biocompatibility as there are no changes in mice’s body weight. When administering peptide-siRNA-DOX, tumor growth is inhibited the most (about three times). These results above prove the sequence to be a good candidate for gene therapy and drug delivery.     

Tumor Microenvironment in Male Breast Carcinoma with Emphasis on Tumor Infiltrating Lymphocytes and PD-L1 Expression

Male breast cancer (MBC) is rare and usually presents as a locally advanced disease. Stromal tumor-infiltrating lymphocytes (sTILs) are associated with a better response to neoadjuvant chemotherapy and improved prognosis in all molecular subtypes of female breast cancer, but their role in MBC is less clear. We studied sTILs and the expression of programmed cell death ligand 1 (PD-L1) and pan-TRK in MBC. We retrospectively studied 113 cases of MBC surgically treated between 1988 and 2015. The tumors were evaluated for histological type and grade, stage, intrinsic subtype and sTILs. We performed immunohistochemistry for PD-L1 (clone SP142) and pan-TRK (clone {"type":"entrez-protein","attrs":{"text":"EPR17341","term_id":"523383444","term_text":"EPR17341"}}EPR17341) on tissue microarrays. Pan-TRK positive cases were further analyzed by next-generation sequencing. The median age was 69 years (range 60–77). Invasive carcinoma of no special type was found in 94.7% of cases, of which 53.1% were grade 2. Estrogen receptor was positive in 92% of the tumors, progesterone receptor in 85.8%, androgen receptor in 70.8%; 4.4% were human epidermal growth factor receptor 2 (HER2)-positive, and 55.8% HER2-low. 40.7% of tumors were luminal A and 51.3% luminal B, 4.4% HER2-enriched and 3.5% triple negative carcinoma. sTILs density was <50% in 96.4% of the tumors, >50% in 3.6% of the tumors. PD-L1 immune cell score >1% was found in 7.1% of the tumors (all of luminal subtype). A weak focal cytoplasmic pan-TRK staining was present in 8.8% but without NTRK fusion. Neither sTILs nor PD-L1 had statistically significant outcomes. Our findings suggest that a subset of MBC patients harbors an immunological environment characterized by increased sTILs with PD-L1 expression. These patients may potentially benefit from immune checkpoint inhibitor therapy. Frequent HER2-low may offer novel anti-HER2 treatment options.     

CHID1 Is a Novel Prognostic Marker of Non-Small Cell Lung Cancer

There is an urgent need for identification of new prognostic markers and therapeutic targets for non-small cell lung cancer (NSCLC). In this study, we evaluated immune cells markers in 100 NSCLC specimens. Immunohistochemical analysis revealed no prognostic value for the markers studied, except CD163 and CD206. At the same time, macrophage markers iNOS and CHID1 were found to be expressed in tumor cells and associated with prognosis. We showed that high iNOS expression is a marker of favorable prognosis for squamous cell lung carcinoma (SCC), and NSCLC in general. Similarly, high CHID1 expression is a marker of good prognosis in adenocarcinoma and in NSCLC in general. Analysis of prognostic significance of a high CHID1/iNOS expression combination showed favorable prognosis with 20 months overall survival of patients from the low CHID1/iNOS expression group. For the first time, we demonstrated that CHID1 can be expressed by NSCLC cells and its high expression is a marker of good prognosis for adenocarcinoma and NSCLC in general. At the same time, high expression of iNOS in tumor cells is a marker of good prognosis in SCC. When used in combination, CHID1 and iNOS show a very good prognostic capacity for NSCLC. We suggest that in the case of lung cancer, tumor-associated macrophages are likely ineffective as a therapeutic target. At the same time, macrophage markers expressed by tumor cells may be considered as targets for anti-tumor therapy or, as in the case of CHID1, as potential anti-tumor agents.     

PD-L1 Expression in Non-Small Cell Lung Cancer Specimens: Association with Clinicopathological Factors and Molecular Alterations

Immune checkpoint inhibitors (ICI) targeting programmed cell death-1 or its ligand (PD-L1) have improved outcomes in non-small cell lung cancer (NSCLC). High tumor PD-L1 expression, detected by immunohistochemistry (IHC) typically on formalin-fixed paraffin-embedded (FFPE) histological specimens, is linked to better response. Following our previous investigation on PD-L1 in cytological samples, the aim of this study was to further explore the potential impacts of various clinicopathological and molecular factors on PD-L1 expression. Two retrospective NSCLC cohorts of 1131 and 651 specimens, respectively, were investigated for PD-L1 expression (<1%/1–49%/≥50%), sample type, sample site, histological type, and oncogenic driver status. In both cohorts, PD-L1 was positive (≥1%) in 55% of the cases. Adenocarcinomas exhibited lower PD-L1 expression than squamous cell carcinomas (p < 0.0001), while there was no difference between sample types, tumor locations, or between the two cohorts in multivariate analysis (all p ≥ 0.28). Mutational status correlated significantly with PD-L1 expression (p < 0.0001), with the highest expression for KRAS-mutated cases, the lowest for EGFR-mutated, and the KRAS/EGFR wild-type cases in between. There was no difference in PD-L1 levels between different prevalent KRAS mutations (all p ≥ 0.44), while mucinous KRAS-mutated adenocarcinomas exhibited much lower PD-L1 expression than non-mucinous (p < 0.0001). Our data indicate that cytological and histological specimens are comparable for PD-L1 evaluation. Given the impact of KRAS mutations and the mucinous growth pattern on PD-L1 expression, these factors should be further investigated in studies on ICI response.     

Diagnostic and Therapeutic Implications of microRNAs in Non-Small Cell Lung Cancer

microRNAs (miRNAs), endogenous suppressors of target mRNAs, are deeply involved in every step of non-small cell lung cancer (NSCLC) development, from tumor initiation to progression and metastasis. They play roles in cell proliferation, apoptosis, angiogenesis, epithelial-to-mesenchymal transition, migration, invasion, and metastatic colonization, as well as immunosuppression. Due to their versatility, numerous attempts have been made to use miRNAs for clinical applications. miRNAs can be used as cancer subtype classifiers, diagnostic markers, drug-response predictors, prognostic markers, and therapeutic targets in NSCLC. Many challenges remain ahead of their actual clinical application; however, when achieved, the use of miRNAs in the clinic is expected to enable great progress in the diagnosis and treatment of patients with NSCLC.     

MiR-122 Induces Radiosensitization in Non-Small Cell Lung Cancer Cell Line

MiR-122 is a novel tumor suppresser and its expression induces cell cycle arrest, or apoptosis, and inhibits cell proliferation in multiple cancer cells, including non-small cell lung cancer (NSCLC) cells. Radioresistance of cancer cell leads to the major drawback of radiotherapy for NSCLC and the induction of radiosensitization could be a useful strategy to fix this problem. The present work investigates the function of miR-122 in inducing radiosensitization in A549 cell, a type of NSCLC cells. MiR-122 induces the radiosensitization of A549 cells. MiR-122 also boosts the inhibitory activity of ionizing radiation (IR) on cancer cell anchor-independent growth and invasion. Moreover, miR-122 reduced the expression of its targeted genes related to tumor-survival or cellular stress response. These results indicate that miR-122 would be a novel strategy for NSCLC radiation-therapy.     

HGF-Induced PD-L1 Expression in Head and Neck Cancer: Preclinical and Clinical Findings

Head and neck squamous cell carcinoma (HNSCC) is a widespread disease with a low survival rate and a high risk of recurrence. Nowadays, immune checkpoint inhibitor (ICI) treatment is approved for HNSCC as a first-line treatment in recurrent and metastatic disease. ICI treatment yields a clear survival benefit, but overall response rates are still unsatisfactory. As shown in different cancer models, hepatocyte growth factor/mesenchymal–epithelial transition (HGF/Met) signaling contributes to an immunosuppressive microenvironment. Therefore, we investigated the relationship between HGF and programmed cell death protein 1 (PD-L1) expression in HNSCC cell lines. The preclinical data show a robust PD-L1 induction upon HGF stimulation. Further analysis revealed that the HGF-mediated upregulation of PD-L1 is MAP kinase-dependent. We then hypothesized that serum levels of HGF and soluble programmed cell death protein 1 (sPD-L1) could be potential markers of ICI treatment failure. Thus, we determined serum levels of these proteins in 20 HNSCC patients before ICI treatment and correlated them with treatment outcomes. Importantly, the clinical data showed a positive correlation of both serum proteins (HGF and sPD-L1) in HNSCC patient’s sera. Moreover, the serum concentration of sPD-L1 was significantly higher in ICI non-responsive patients. Our findings indicate a potential role for sPD-L1 as a prognostic marker for ICI treatment in HNSCC.     

Clinical and Prognostic Value of Antigen-Presenting Cells with PD-L1/PD-L2 Expression in Ovarian Cancer Patients

The latest literature demonstrates the predominant role of the programmed cell death axis (PD-1/PD-L1/PD-L2) in ovarian cancer (OC) pathogenesis. However, data concerning this issue is ambiguous. Our research aimed to evaluate the clinical importance of PD-L1/PD-L2 expression in OC environments. We evaluated the role of PD-L1/PD-L2 in OC patients (n = 53). The analysis was performed via flow cytometry on myeloid (mDCs) and plasmacytoid dendritic cells (pDCs) and monocytes/macrophages (MO/MA) in peripheral blood, peritoneal fluid (PF), and tumor tissue (TT). The data were correlated with clinicopathological characteristics and prognosis of OC patients. The concentration of soluble PD-L1 (sPD-L1) and PD-1 in the plasma and PF were determined by ELISA. We established an accumulation of PD-L1⁺/PD-L2⁺ mDCs, pDCs, and MA in the tumor microenvironment. We showed an elevated level of sPD-L1 in the PF of OC patients in comparison to plasma and healthy subjects. sPD-L1 levels in PF showed a positive relationship with Ca125 concentration. Moreover, we established an association between higher sPD-L1 levels in PF and shorter survival of OC patients. An accumulation of PD-L1⁺/PD-L2⁺ mDCs, pDCs, and MA in the TT and high sPD-L1 levels in PF could represent the hallmark of immune regulation in OC patients.