Upregulation of Bcl2 in NSCLC with acquired resistance to EGFR-TKI

Vismodegib Potentiates Marine Antimicrobial Peptide Tilapia Piscidin 4-Induced Cytotoxicity in Human Non-Small Cell Lung Cancer Cells

Non-small cell lung cancer (NSCLC) is a common cancer with several accepted treatments, such as chemotherapy, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, and immune checkpoint inhibitors. Nevertheless, NSCLC cells often become insensitive to these treatments, and therapeutic resistance is a major reason NSCLC still has a high mortality rate. The induction of therapeutic resistance in NSCLC often involves hedgehog, and suppression of hedgehog can increase NSCLC cell sensitivity to several conventional therapies. In our previous work, we demonstrated that the marine antimicrobial peptide tilapia piscidin 4 (TP4) exhibits potent anti-NSCLC activity in both EGFR-WT and EGFR-mutant NSCLC cells. Here, we sought to further explore whether hedgehog might influence the sensitivity of NSCLC cells to TP4. Our results showed that hedgehog was activated by TP4 in both WT and EGFR-mutant NSCLC cells and that pharmacological inhibition of hedgehog by vismodegib, a Food and Drug Administration-approved hedgehog inhibitor, potentiated TP4-induced cytotoxicity. Mechanistically, vismodegib acted by enhancing TP4-mediated increases in mitochondrial membrane potential and intracellular reactive oxygen species (ROS). MitoTempo, a specific mitochondrial ROS scavenger, abolished vismodegib/TP4 cytotoxicity. The combination of vismodegib with TP4 also reduced the levels of the antioxidant proteins catalase and superoxide dismutase, and it diminished the levels of chemoresistance-related proteins, Bcl-2 and p21. Thus, we conclude that hedgehog regulates the cytotoxic sensitivity of NSCLC cells to TP4 by protecting against mitochondrial dysfunction and suppressing oxidative stress. These findings suggest that combined treatment of vismodegib and TP4 may be a promising therapeutic strategy for NSCLC.

YES1 as a potential target to overcome drug resistance in EGFR-deregulated non-small cell lung cancer

Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) such as gefitinib and osimertinib have primarily been used as first-line treatments for patients with EGFR-activating mutations in non-small cell lung cancer (NSCLC). Novel biomarkers are required to distinguish patients with lung cancer who are resistant to EGFR-TKIs. The aim of the study is to investigate the expression and functional role of YES1, one of the Src-family kinases, in EGFR-TKI-resistant NSCLC. YES1 expression was elevated in gefitinib-resistant HCC827 (HCC827/GR) cells, harboring EGFR mutations. Moreover, HCC827/GR cells exhibited increased reactive oxygen species (ROS) levels compared to those of the parent cells, resulting in the phosphorylation/activation of YES1 due to oxidation of the cysteine residue. HCC827/GR cells showed elevated expression levels of YES1-associated protein 1 (YAP1), NF-E2-related factor 2 (Nrf2), cancer stemness-related markers, and antioxidant proteins compared to those of the parent cells. Knockdown of YES1 in HCC827/GR cells suppressed YAP1 phosphorylation, leading to the inhibition of Bcl-2, Bcl-xL, and Cyclin D1 expression. Silencing YES1 markedly attenuated the proliferation, migration, and tumorigenicity of HCC827/GR cells. Dasatinib inhibited the proliferation of HCC827/GR cells by targeting YES1-mediated signaling pathways. Furthermore, the combination of gefitinib and dasatinib demonstrated a synergistic effect in suppressing the proliferation of HCC827/GR cells. Notably, YES1- and Nrf2-regulated genes showed a positive regulatory relationship in patients with lung cancer and in TKI-resistant NSCLC cell lines. Taken together, these findings suggest that modulation of YES1 expression and activity may be an attractive therapeutic strategy for the treatment of drug-resistant NSCLC.

Expression Level and Clinical Significance of AK021443 in Non-Small-Cell Lung Carcinoma

To explore the prognostic potential of AK021443 in non-small-cell lung carcinoma (NSCLC), AK021443 levels in NSCLC specimens were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between the AK021443 level and pathological factors in NSCLC patients was analyzed. Kaplan-Meier curves were plotted for assessing the prognostic value of AK021443 in NSCLC patients. Potential factors influencing NSCLC prognosis were analyzed by multivariable Cox regression test. AK021443 was upregulated in NSCLC specimens than normal ones. Its level was correlated to histological type, tumor differentiation, TNM staging, and lymphatic metastasis in NSCLC patients. AK021443 was the independent risk factor for the overall survival of NSCLC. AK021443 is highly expressed in NSCLC specimens, which is correlated to histological type, tumor differentiation, TNM staging, and lymphatic metastasis in NSCLC patients. It is the independent prognostic factor for NSCLC.

IKKα Induces Epithelial–Mesenchymal Changes in Mouse Skin Carcinoma Cells That Can Be Partially Reversed by Apigenin

NMSC (non-melanoma skin cancer) is a common tumor in the Caucasian population, accounting for 90% of skin cancers. Among them, squamous cell carcinomas (SCCs) can metastasize and, due to its high incidence, constitute a severe health problem. It has been suggested that cutaneous SCCs with more risk to metastasize express high levels of nuclear IKKα. However, the molecular mechanisms that lead to this enhanced aggressiveness are largely unknown. To understand in depth the influence of nuclear IKKα in skin SCC progression, we have generated murine PDVC57 skin carcinoma cells expressing exogenous IKKα either in the nucleus or in the cytoplasm to further distinguish the tumor properties of IKKα in both localizations. Our results show that IKKα promotes changes in both subcellular compartments, resembling EMT (epithelial–mesenchymal transition), which are more pronounced when IKKα is in the nucleus of these tumor cells. These EMT-related changes include a shift toward a migratory phenotype and induction of the expression of proteins involved in cell matrix degradation, cell survival and resistance to apoptosis. Additionally, we have found that apigenin, a flavonoid with anti-cancer properties, inhibits the expression of IKKα and attenuates most of the pro-tumoral EMT changes induced by IKKα in mouse tumor keratinocytes. Nevertheless, we have found that apigenin only inhibits the expression of the IKKα protein when it is localized in the cytoplasm.

Prediction of Genes Involved in Lung Cancer with a Systems Biology Approach Based on Comprehensive Gene Information

Over the past few years, hundreds of genes have been reported in relation to lung cancer. Systems biology studies can help validate this association and find the most valid genes to use in the diagnosis and treatment. We reviewed the candidate genes for lung cancer in 120 published articles from September 1, 1993, to September 1, 2020. We obtained 134 up- and 36 downregulated genes for lung cancer in this article. The genes extracted from the articles were imported to Search Tool for the Retrieval of Interacting genes/proteins (STRING) to construct the protein-protein interaction (PPI) Network and pathway enrichment. GO ontology and Reactome databases were used for describing the genes, average length of survival, and constructing networks. Then, the ClusterONE plugin of Cytoscape software was used to analyze and cluster networks. Hubs and bottleneck nodes were defined based on their degree and betweenness. Common genes between the ClusterONE plugin and network analysis consisted of seven genes (BRCA1-TP53-CASP3-PLK1-VEGFA-MDM2-CCNB1 and PLK1), and two genes (PLK1 and TYMS) were selected as survival factors. Our drug-gene network showed that CASP3, BRCA1, TP53, VEGFA, and MDM2 are common genes that are involved in this network. Also, among the drugs recognized in the drug-gene network, five drugs such as paclitaxel, oxaliplatin, carboplatin, irinotecan, and cisplatin were examined in different studies. It seems that these seven genes, with further studies and confirmatory tests, could be potential markers for lung cancer, especially PLK1 that has a significant effect on the survival of patients. We provide the novel genes into the pathogenesis of lung cancer, and we introduced new potential biomarkers for this malignancy.

ARID1A serves as a receivable biomarker for the resistance to EGFR-TKIs in non-small cell lung cancer

ARID1A is a key component of the SWI/SNF chromatin remodeling complexes which is important for the maintaining of biological processes of cells. Recent studies had uncovered the potential role of ARID1A alterations or expression loss in the therapeutic sensitivity of cancers, but the studies in this field requires to be further summarized and discussed. Therefore, we proposed a series of mechanisms related to the resistance to EGFR-TKIs induced by ARID1A alterations or expression loss and the potential therapeutic strategies to overcome the resistance based on published studies. It suggested that ARID1A alterations or expression loss might be the regulators in PI3K/Akt, JAK/STAT and NF-κB signaling pathways which are strongly associated with the resistance to EGFR-TKIs in NSCLC patients harboring sensitive EGFR mutations. Besides, ARID1A alterations or expression loss could lead to the resistance to EGFR-TKIs via a variety of processes during the tumorigenesis and development of cancers, including epithelial to mesenchymal transition, angiogenesis and the inhibition of apoptosis. Based on the potential mechanisms related to ARID1A, we summarized that the small molecular inhibitors targeting ARID1A or PI3K/Akt pathway, the anti-angiogenic therapy and immune checkpoint inhibitors could be used for the supplementary treatment for EGFR-TKIs among NSCLC patients harboring the concomitant alterations of sensitive EGFR mutations and ARID1A.

Synergistic effects of Bcl-2 inhibitors with AZD9291 on overcoming the acquired resistance of AZD9291 in H1975 cells

Non-small cell lung cancer (NSCLC) patients with epithermal growth factor receptor (EGFR) mutations can be treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs), however, development of acquired resistance could significantly limit curative effects of EGFR-TKIs. Different mechanisms of acquired resistance to first-generation and second-generation EGFR TKIs have been widely reported, but there were few reports on the resistant mechanism of third-generation EGFR-TKI such as osimertinib (AZD9291). In the present study, significant upregulation of Bcl-2 was found in AZD9291-resistant H1975 cells (H1975AR) compared with H1975, which may constitute an important resistant mechanism of acquired resistance to AZD9291. More importantly, our study showed that synergism between AZD9291 and Bcl-2 inhibitor ABT263 (0.25 μM) or ABT199 (1 μM) could effectively overcome the acquired resistance of AZD9291 in H1975AR in vitro. Flow cytometry analyses demonstrated that AZD9291 + ABT263/ABT199 caused a significantly different cell cycle distribution and produced significantly more apoptosis compared with either AZD9291 or ABT263/ABT199 treatment alone. Further multiscreen/Western blot analyses revealed that NF-κB was significantly downregulated in AZD9291 + ABT263/ABT199 treatment groups compared with AZD9291 or ABT263/ABT199 treatment alone, with a more significant reduction of NF-κB in AZD9291 + ABT199 compared with AZD9291 + ABT263. It is also noticeable that AZD9291 + ABT263 specifically caused a significantly reduced expression of p21 compared with AZD9291 or ABT263 treatment alone while AZD9291 + ABT199 specifically caused significantly reduced expressions of SQSTM1 and survivin, but increased expression of autophagosome marker LC3-II compared with AZD9291 or ABT199 treatment alone. Furthermore, cytotoxicity of AZD9291 + ABT199 could be partially reversed by autophagy inhibitor chloroquine. These results suggest that ABT263 and ABT199 may work through different signaling pathways to achieve synergistic cytotoxicity with AZD9291 in H1975AR. These findings suggest that Bcl-2 inhibitor may provide an effective option in combination therapy with EGFR-TKIs to treat NSCLC with EGFR-TKI acquired resistance.

Chalcomoracin inhibits cell proliferation and increases sensitivity to radiotherapy in human non-small cell lung cancer cells via inducing endoplasmic reticulum stress-mediated paraptosis

Chalcomoracin (CMR) is a kind of Diels–Alder adduct extracted from the mulberry leaves. Recent studies showed that CMR has a broad spectrum of anticancer activities and induces paraptosis in breast cancer and prostate cancer cells. In this study, we investigated the effects of CMR against human non-small cell lung cancer cells and the underlying mechanisms. We found that CMR dose-dependently inhibited the proliferation of human lung cancer H460, A549 and PC-9 cells. Furthermore, exposure to low and median doses of CMR induced paraptosis but not apoptosis, which was presented as the formation of extensive cytoplasmic vacuolation with increased expression of endoplasmic reticulum stress markers, Bip and Chop, as well as activation of MAPK pathway in the lung cancer cells. Knockdown of Bip with siRNA not only reduced the cell-killing effect of CMR, but also decreased the percentage of cytoplasmic vacuoles in H460 cells. Moreover, CMR also increased the sensitivity of lung cancer cells to radiotherapy through enhanced endoplasmic reticulum stress. In lung cancer H460 cell xenograft nude mice, combined treatment of CMR and radiation caused greatly enhanced tumor growth inhibition with upregulation of endoplasmic reticulum stress proteins and activation of pErk in xenograft tumor tissue. These data demonstrate that the anticancer activity and radiosensitization effect of CMR result from inducing paraptosis, suggesting that CMR could be considered as a potential anticancer agent and radiation sensitizer in the future cancer therapeutics.

Targeting Mitochondrial Apoptosis to Overcome Treatment Resistance in Cancer

Deregulated cellular apoptosis is a hallmark of cancer and chemotherapy resistance. The B-cell lymphoma 2 (BCL-2) protein family members are sentinel molecules that regulate the mitochondrial apoptosis machinery and arbitrate cell fate through a delicate balance between pro- and anti-apoptotic factors. The recognition of the anti-apoptotic BCL2 gene as an oncogenic driver in hematological malignancies has directed attention toward unraveling the biological significance of each of the BCL-2 superfamily members in cancer progression and garnered interest in the targeting of apoptosis in cancer therapy. Accordingly, the approval of venetoclax (ABT-199), a small molecule BCL-2 inhibitor, in patients with chronic lymphocytic leukemia and acute myeloid leukemia has become the proverbial torchbearer for novel candidate drug approaches selectively targeting the BCL-2 superfamily. Despite the inspiring advances in this field, much remains to be learned regarding the optimal therapeutic context for BCL-2 targeting. Functional assays, such as through BH3 profiling, may facilitate prediction of treatment response, development of drug resistance and shed light on rational combinations of BCL-2 inhibitors with other branches of cancer therapy. This review summarizes the pathological roles of the BCL-2 family members in cancer, discusses the current landscape of their targeting in clinical practice, and highlights the potential for future therapeutic inroads in this important area.

The role of MDM2 amplification and overexpression in therapeutic resistance of malignant tumors

The MDM2 protein encoded by the mouse double minute 2 (MDM2) gene is the primary negative regulatory factor of the p53 protein. MDM2 can ligate the p53 protein via its E3 ubiquitin ligase, and the ubiquitinated p53 can be transferred to the cytoplasm and degraded by proteasomes. Therefore, MDM2 can maintain the stability of p53 signaling pathway. MDM2 amplification has been detected in many human malignancies, including lung cancer, colon cancer and other malignancies. MDM2 overexpression is associated with chemotherapeutic resistance in human malignancies. The mechanisms of chemotherapeutic resistance by MDM2 overexpression mainly include the p53–MDM2 loop-dependent and p53–MDM2 loop-independent pathways. But the role of MDM2 overexpression in tyrosine kinase inhibitors resistance remains to be further study. This paper reviews the possible mechanisms of therapeutic resistance of malignancies induced by MDM2 amplification and overexpression, including chemotherapy, radiotherapy, targeted agents and hyperprogressive disease of immunotherapy. Besides, MDM2-targeted therapy may be a potential new strategy for treating advanced malignancies.

IKKα Promotes the Progression and Metastasis of Non-Small Cell Lung Cancer Independently of its Subcellular Localization

Lung cancer is the leading worldwide cause of cancer mortality, however, neither curative treatments nor substantial prolonged survival has been achieved, highlighting the need for investigating new proteins responsible for its development and progression. IKKα is an essential protein for cell survival and differentiation, which expression is enhanced in human non-small cell lung cancer (NSCLC) and correlates with poor patient survival, appearing as a relevant molecule in lung cancer progression. However, there are not conclusive results about its role in this type of cancer. We have recently found that IKKα performs different functions and activates different signaling pathways depending on its nuclear or cytoplasmic localization in tumor epidermal cells. In this work, we have studied the involvement of IKKα in lung cancer progression through the generation of lung cancer cell lines expressing exogenous IKKα either in the nucleus or in the cytoplasm. We demonstrate that IKKα signaling promotes increased cell malignancy of NSCLC cells as well as lung tumor progression and metastasis in either subcellular localization, through activation of common protumoral proteins, such as Erk, p38 and mTor. But, additionally, we found that depending on its subcellular localization, IKKα has non-overlapping roles in the activation of other different pathways known for their key implication in lung cancer progression: while cytoplasmic IKKα increases EGFR and NF-κB activities in lung tumor cells, nuclear IKKα causes lung tumor progression through c-Myc, Smad2/3 and Snail activation. These results suggest that IKKα may be a promising target for intervention in human NSCLC.

Investigate the mechanisms of Chinese medicine Fuzhengkangai towards EGFR mutation-positive lung adenocarcinomas by network pharmacology

BACKGROUND

Chinese traditional herbal medicine Fuzhengkangai (FZKA) formulation combination with gefitinib can overcome drug resistance and improve the prognosis of lung adenocarcinoma patients. However, the pharmacological and molecular mechanisms underlying the active ingredients, potential targets, and overcome drug resistance of the drug are still unclear. Therefore, it is necessary to explore the molecular mechanism of FZKA.

METHODS

A systems pharmacology and bioinformatics-based approach was employed to investigate the molecular pathogenesis of EGFR-TKI resistance with clinically effective herb formula. The differential gene expressions between EGFR-TKI sensitive and resistance cell lines were calculated and used to find overlap from targets as core targets. The prognosis of core targets was validated from the cancer genome atlas (TCGA) database by Cox regression. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment is applied to analysis core targets for revealing mechanism in biology.

RESULTS

The results showed that 35 active compounds of FZKA can interact with eight core targets proteins (ADRB2, BCL2, CDKN1A, HTR2C, KCNMA1, PLA2G4A, PRKCA and LYZ). The risk score of them were associated with overall survival and relapse free time (HR = 6.604, 95% CI: 2.314-18.850; HR = 5.132, 95% CI: 1.531-17.220). The pathway enrichment suggested that they involved in EGFR-TKI resistance and non-small cell lung cancer pathways, which directly affect EGFR-TKI resistance. The molecular docking showed that licochalcone a and beta-sitosterol can closely bind two targets (BCL2 and PRKCA) that involved in EGFR-TKI resistance pathway.

CONCLUSIONS

This study provided a workflow for understanding mechanism of CHM for against drug resistance.