Lung Cancer Cell Survival Research Articles

Biased signaling by mutant EGFR underlies dependence on PKCα in lung adenocarcinoma

Activating mutations in the epidermal growth factor receptor (EGFR) promote ligand-independent signaling; however, the mechanisms involved are poorly defined, and it is unknown whether this generates specific vulnerabilities. We previously observed robust expression of protein kinase Cα (PKCα) in lung adenocarcinoma (LUAD) with mutant EGFR (mEGFR), which, unlike the activation of PKCα, is independent of mEGFR activity. Here, we identify a critical role for PKCα in anchorage-independent growth and survival of lung cancer cells with mEGFR. Mechanistically, signaling pathways initiated by mEGFR show a high preference for ligand-independent phosphorylation on Y992, resulting in biased activation and dependence on phospholipase-Cγ and PKCα. Moreover, through bioinformatic approaches, we find that mEGFR LUAD demonstrates a transcriptomic profile most similar to lung basal cells, which exhibit elevated levels of PKCα, suggesting that mEGFR tumors arise in cell types with high intrinsic levels of PKCα. Taken together, these findings explain the dependence of mEGFR on PKCα.

Targeting PI3K/AKT/mTOR Signalling pathway in non-small-cell lung carcinoma: Exploring promising bioactive natural compounds as anti-cancer agents

Lung cancer has become the most common solid tumor and the leading cause of cancer-related deaths worldwide. It is estimated that the annual mortality rate for lung cancer is 1.8 million out of which 85% are non-small-cell lung cancer (NSCLC) cases. PI3K/Akt/mTOR signalling pathways play a critical role in both pathological and physiological situations, influencing different aspects of cell survival and proliferation in lung cancer. Despite the use of several therapies, lung cancer treatment has been found to be insufficient, leading to unsatisfactory patient outcomes. There has been a growing interest in natural compounds derived from plants, due to their easy availability, low toxicity, cost-effectiveness, and ability to regulate various biological pathways. Therefore, in the current investigation, we studied various natural compounds having an inhibitory action on PI3K/Akt/mTOR signalling pathways in lung cancer by inducing apoptosis. Further, natural compounds like vitexin, betalain, morusin, bromophenol erianin, peruvoside, and resveratrol were found to decrease Bcl-2 and Bcl-xl expression, whereas elevated BAX, caspase-3, caspase-7, and caspase-9 expression leading to apoptosis and downregulation of p-PI3K/p-Akt/p-mTOR expression in NSCLC.The ultimate goal is to create new and safe treatments for the prevention and treatment of lung cancer.

Combined Treatment of Caffeic Acid Phenethyl Ester With Docetaxel Inhibits Survival of Non-small-cell Lung Cancer Cells via Suppression of c-MYC.

Non-small-cell lung cancer (NSCLC) comprises approximately 85% of lung cancer. Treatment with docetaxel prolongs the survival of patients with NSCLC. However, the development of resistance to docetaxel has compromised its efficacy. Caffeic acid phenethyl ester (CAPE) has been reported to suppress survival and radiotherapy resistance in lung cancer cells. We determined in this study if combination treatment of docetaxel with CAPE suppresses the proliferation and the survival of NSCLC cells more effectively. Proliferation, viability, flow cytometric and comet assays were used to examine the difference in anticancer effects of combined treatment as compared to docetaxel treatment alone. Western blot and gene overexpression were used to unravel the underlying molecular mechanism. Treatment with docetaxel or CAPE alone dose-dependently suppressed the proliferation and survival of H1299 and A549 cells. Combined treatment of docetaxel with CAPE caused greater inhibition of survival of H1299 and A549 cells. Docetaxel alone and the combined treatment both dose-dependently increased apoptosis of H1299 cells; however, combined treatment induced much more apoptosis than docetaxel alone. Combined treatment suppressed the protein expression of phospho-protein kinase B (AKT, Ser 473), S-phase protein 2 (SKP2), MYC proto-oncogene bHLH transcription factor (c-MYC), epidermal growth factor receptor (EGFR), phospho-EGFR (Tyr 1045, and Tyr 992) but increased levels of cleaved caspase 3 and cytochrome c proteins in H1299 and A549 cells. The inhibition of expression of SKP2, c-MYC, phospho-EGFR (Tyr 992) proteins by combined treatment was significantly greater than that with treatment using either CAPE or docetaxel alone. Overexpression of c-MYC in rescued proliferation of H1299 cells under combination treatment. Our study revealed that the combination of CAPE with docetaxel is more effective at reducing the proliferation and survival of NSCLC cells, and this is via inhibition of c-MYC. Combined therapy of docetaxel and CAPE may benefit patients with NSCLC.

ML385, an Nrf2 Inhibitor, Synergically Enhanced Celastrol Triggered Endoplasmic Reticulum Stress in Lung Cancer Cells.

Lung cancer is one of the leading causes of death. Celastrol is a natural product that has shown anticancer activity but has not yet been applied in clinical settings due to its narrow therapeutic window. In this study, we discovered that celastrol stimulates an abnormal rise in the reactive oxygen species (ROS) level in lung cancer cells and that the ROS scavenger N-acetylcysteine (NAC) could counteract the cell death caused by celastrol. At the same time, celastrol upregulated the expression of cytoprotective transcription factor Nrf2 and its downstream proteins, which are effective in preventing the oxidative damage caused by ROS accumulation. Notably, we found that the overexpression of Nrf2 enhances the tolerance of lung cancer cells to celastrol and that lung cancer cells H460 with a Keap1 mutation are insensitive to celastrol. This indicates that the increase in Nrf2 contributes to the survival of lung cancer cells. Thus, we brought in an Nrf2 inhibitor ML385 to suppress the activation of Nrf2. We found that when ML385 and celastrol were added together the survival rates of lung cancer cells decreased more and the detected ROS level became much higher compared to treatment with celastrol alone. We also discovered that ML385 suppressed the expression of HO-1 and GCLC, which amplified celastrol-induced ATF4/CHOP-dependent endoplasmic reticulum stress (ER stress). Above all, our study found that ML385 enhanced celastrol-induced increases in ROS and ER stress, leading to lung cancer cell death. This research provides a potential strategy for the preclinical investigation of celastrol.

O-GlcNAcylation promotes malignancy and cisplatin resistance of lung cancer by stabilising NRF2.

The transcription factor NRF2 plays a significant role in regulating genes that protect cells from oxidative damage. O-GlcNAc modification, a type of posttranslational modification, is crucial for cellular response to stress. Although the involvement of both NRF2 and O-GlcNAc in maintaining cellular redox balance and promoting cancer malignancy has been demonstrated, the potential mechanisms remain elusive. The immunoblotting, luciferase reporter, ROS assay, co-immunoprecipitation, and immunofluorescence was used to detect the effects of global cellular O-GlcNAcylation on NRF2. Mass spectrometry was utilised to map the O-GlcNAcylation sites on NRF2, which was validated by site-specific mutagenesis and O-GlcNAc enzymatic labelling. Human lung cancer samples were employed to verify the association between O-GlcNAc and NRF2. Subsequently, the impact of NRF2 O-GlcNAcylation in lung cancer malignancy and cisplatin resistance were evaluated in vitro and in vivo. NRF2 is O-GlcNAcylated at Ser103 residue, which hinders its binding to KEAP1 and thus enhances its stability, nuclear localisation, and transcription activity. Oxidative stress and cisplatin can elevate the phosphorylation of OGT at Thr444 through the activation of AMPK kinase, leading to enhanced binding of OGT to NRF2 and subsequent elevation of NRF2 O-GlcNAcylation. Both in cellular and xenograft mouse models, O-GlcNAcylation of NRF2 at Ser103 promotes the malignancy of lung cancer. In human lung cancer tissue samples, there was a significant increase in global O-GlcNAcylation, and elevated levels of NRF2 and its O-GlcNAcylation compared to paired adjacent normal tissues. Chemotherapy promotes NRF2 O-GlcNAcylation, which in turn decreases cellular ROS levels and drives lung cancer cell survival. Our findings indicate that OGT O-GlcNAcylates NRF2 at Ser103, and this modification plays a role in cellular antioxidant, lung cancer malignancy, and cisplatin resistance.

IGFBP2/ITGA5 promotes gefitinib resistance via activating STAT3/CXCL1 axis in non-small cell lung cancer

There is a paucity of comprehensive knowledge pertaining to the underlying mechanisms leading to gefitinib resistance in individuals diagnosed NSCLC harboring EGFR-sensitive mutations who inevitably develop resistance to gefitinib treatment within six months to one year. In our preceding investigations, we have noted a marked upregulation of IGFBP2 in the neoplastic tissues of NSCLC, predominantly in the periphery of the tissue, implying its plausible significance in NSCLC. Consequently, in the current research, we delved into the matter and ascertained the molecular mechanisms that underlie the participation of IGFBP2 in the emergence of gefitinib resistance in NSCLC cells. Firstly, the expression of IGFBP2 in the bronchoalveolar lavage fluid and lung cancer tissues of 20 NSCLC patients with gefitinib tolerance was found to be significantly higher than that of non-tolerant patients. Furthermore, in vitro and in vivo experiments demonstrated that IGFBP2 plays a significant role in the acquisition of gefitinib resistance. Mechanistically, IGFBP2 can activate STAT3 to enhance the transcriptional activity of CXCL1, thereby increasing the intracellular expression level of CXCL1, which contributes to the survival of lung cancer cells in the gefitinib environment. Additionally, we identified ITGA5 as a key player in IGFBP2-mediated gefitinib resistance, but it does not function as a membrane receptor in the process of linking IGFBP2 to intracellular signaling transduction. In conclusion, this study demonstrates the promoting role and mechanism of IGFBP2 in acquired gefitinib resistance caused by non-EGFR secondary mutations, suggesting the potential of IGFBP2 as a biomarker for gefitinib resistance and a potential intervention target.

Amyloid Beta Leads to Decreased Acetylcholine Levels and Non-Small Cell Lung Cancer Cell Survival via a Mechanism That Involves p38 Mitogen-Activated Protein Kinase and Protein Kinase C in a p53-Dependent and -Independent Manner.

Several studies have shown an inverse correlation between the likelihood of developing a neurodegenerative disorder and cancer. We previously reported that the levels of amyloid beta (Aβ), at the center of Alzheimer's disease pathophysiology, are regulated by acetylcholinesterase (AChE) in non-small cell lung cancer (NSCLC). Here, we examined the effect of Aβ or its fragments on the levels of ACh in A549 (p53 wild-type) and H1299 (p53-null) NSCLC cell media. ACh levels were reduced by cell treatment with Aβ 1-42, Aβ 1-40, Aβ 1-28, and Aβ 25-35. AChE and p53 activities increased upon A549 cell treatment with Aβ, while knockdown of p53 in A549 cells increased ACh levels, decreased AChE activity, and diminished the Aβ effects. Aβ increased the ratio of phospho/total p38 MAPK and decreased the activity of PKC. Inhibiting p38 MAPK reduced the activity of p53 in A549 cells and increased ACh levels in the media of both cell lines, while opposite effects were found upon inhibiting PKC. ACh decreased the activity of p53 in A549 cells, decreased p38 MAPK activity, increased PKC activity, and diminished the effect of Aβ on those activities. Moreover, the negative effect of Aβ on cell viability was diminished by cell co-treatment with ACh.

Short-chain fatty acids induced lung tumor cell death and increased peripheral blood CD4+ T cells in NSCLC and control patients ex vivo.

Despite therapy advances, one of the leading causes of cancer deaths still remains lung cancer. To improve current treatments or prevent non-small cell lung cancer (NSCLC), the role of the nutrition in cancer onset and progression needs to be understood in more detail. While in colorectal cancer, the influence of local microbiota derived SCFAs have been well investigated, the influence of SCFA on lung cancer cells via peripheral blood immune system should be investigated more deeply. In this respect, nutrients absorbed via the gut might affect the tumor microenvironment (TME) and thus play an important role in tumor cell growth. This study focuses on the impact of the short-chain fatty acid (SCFA) Sodium Butyrate (SB), on lung cancer cell survival. We previously described a pro-tumoral role of glucose on A549 lung adenocarcinoma cell line. In this study, we wanted to know if SB would counteract the effect of glucose and thus cultured A549 and H520 in vitro with and without SB in the presence or absence of glucose and investigated how the treatment with SB affects the survival of lung cancer cells and its influence on immune cells fighting against lung cancer. In this study, we performed cell culture experiments with A549, H520 and NSCLC-patient-derived epithelial cells under different SB levels. To investigate the influence on the immune system, we performed in vitro culture of peripheral mononuclear blood cells (PBMC) from control, smoker and lung cancer patients with increasing SB concentrations. To investigate the effect of SB on lung tumor cells, we first analyzed the effect of 6 different concentrations of SB on A549 cells at 48 and 72 hours cell culture. Here we found that, SB treatment reduced lung cancer cell survival in a concentration dependent manner. We next focused our deeper analysis on the two concentrations, which caused the maximal reduction in cell survival. Here, we observed that SB led to cell cycle arrest and induced early apoptosis in A549 lung cancer cells. The expression of cell cycle regulatory proteins and A549 lung cancer stem cell markers (CD90) was induced. Additionally, this study explored the role of interferon-gamma (IFN-γ) and its receptor (IFN-γ-R1) in combination with SB treatment, revealing that, although IFN-γ-R1 expression was increased, IFN-γ did not affect the efficacy of SB in reducing tumor cell viability. Furthermore, we examined the effects of SB on immune cells, specifically CD8+ T cells and natural killer (NK) cells from healthy individuals, smokers, and NSCLC patients. SB treatment resulted in a decreased production of IFN-γ and granzyme B in CD8+ T cells and NK cells. Moreover, SB induced IFN-γ-R1 in NK cells and CD4+ T cells in the absence of glucose both in PBMCs from controls and NSCLC subjects. Overall, this study highlights the potential of SB in inhibiting lung cancer cell growth, triggering apoptosis, inducing cell cycle arrest, and modulating immune responses by activating peripheral blood CD4+ T cells while selectively inducing IFN-γ-R1 in NK cells in peripheral blood and inhibiting peripheral blood CD8+ T cells and NK cells. Thus, understanding the mechanisms of action of SB in the TME and its influence on the immune system provide valuable insights of potentially considering SB as a candidate for adjunctive therapies in NSCLC.

Abstract 4593: A synergy between MDM2 and AURKB pathways in driving cell cycle and cell survival in lung cancer cells

Abstract Lung cancer is the leading cause of cancer-related deaths worldwide and non-small cell lung cancer (NSCLC) is the most prevalent type among lung cancers, contributing to the high mortality seen with this deadly disease. Despite aggressive treatments, the 5-year survival rate for lung cancer is only 23.7% in the United States. MDM2 and AURKB are two cancer-driving genes that are highly expressed in a broad range of cancer types including lung cancers. Furthermore, MDM2 overexpression can positively impact AURKB expression and contribute to oncogenesis and cancer progression. Therefore, blocking MDM2 with specific inhibitors has become a promising strategy for the restoration of p53 function that could be used for the treatment of different types of cancers including lung cancers. In this regard, both MDM2 and AURKB inhibitors have shown promising antitumor activity against NSCLC. Therefore, the main objective of this study was to understand the molecular mechanisms linking MDM2 and ARKB using RG7388, CM272, BMS-582949 (p38 inhibitor), and Ralimetinib (p38 inhibitor) in A549 and H460 lung cancer cells. We analyzed the individual or combination treatment effects of these drugs on epigenetic modifications, cell cycle arrest, and cell death mechanisms, using the in vitro experimental model. When RG7388 was used individually, or in combination with BMS-582949 or Ralimetinib, a significant increase in the cytotoxic effect was observed in A549 and H460 cells. Induction of cell cycle arrest by RG7388 in cancer cells was evidenced by elevated p21 expression levels. In addition, RG7388 and combination treatments in NSCLC cells showed significant upregulation of p53, p27, Bax, cleaved PARP, phospho-FOXO3a and down-regulation in DNMT3a, DNMT1, FOXM1, AURKB, CDC25, and CDK4 levels. It appears that during treatments with a combination of MDM2 with DNMT or p38 inhibitor, two pathways might be blocked simultaneously, which could lead to increased cancer cell death. RG7388 appears to induce cell death in a p21-dependent manner and CM272, BMS-582949, and Ralimetinib seem to induce cell death via a p21-independent manner by inhibiting a downstream pathway. However, further studies are needed to fully understand the intracellular link between MDM2 and AURKB that is disrupted by the anti-cancer agents used in our study. (This project was supported by the PFRDG Grant of Nova Southeastern University and by the Generous support from the Royal Dames of Cancer Research Ft. Lauderdale, FL) Citation Format: Umamaheswari Natarajan, Appu Rathinavelu. A synergy between MDM2 and AURKB pathways in driving cell cycle and cell survival in lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4593.

Activation of polyamine catabolism promotes glutamine metabolism and creates a targetable vulnerability in lung cancer

Polyamines are a class of small polycationic alkylamines that play essential roles in both normal and cancer cell growth. Polyamine metabolism is frequently dysregulated and considered a therapeutic target in cancer. However, targeting polyamine metabolism as monotherapy often exhibits limited efficacy, and the underlying mechanisms are incompletely understood. Here we report that activation of polyamine catabolism promotes glutamine metabolism, leading to a targetable vulnerability in lung cancer. Genetic and pharmacological activation of spermidine/spermine N1-acetyltransferase 1 (SAT1), the rate-limiting enzyme of polyamine catabolism, enhances the conversion of glutamine to glutamate and subsequent glutathione (GSH) synthesis. This metabolic rewiring ameliorates oxidative stress to support lung cancer cell proliferation and survival. Simultaneous glutamine limitation and SAT1 activation result in ROS accumulation, growth inhibition, and cell death. Importantly, pharmacological inhibition of either one of glutamine transport, glutaminase, or GSH biosynthesis in combination with activation of polyamine catabolism synergistically suppresses lung cancer cell growth and xenograft tumor formation. Together, this study unveils a previously unappreciated functional interconnection between polyamine catabolism and glutamine metabolism and establishes cotargeting strategies as potential therapeutics in lung cancer.

Targeting MEK in non-small cell lung cancer

The mitogen-activated protein kinase (MAPK or MEK) pathway modulates tumor cell survival and proliferation in non-small cell lung cancer (NSCLC). Unlike RAS or EGFR, activating mutations in MEK are exceedingly rare in NSCLC. Instead, enhanced activation of the MEK pathway is often linked to increased signaling by upstream oncogenic driver mutations. Thus far, MEK inhibitor monotherapy has shown little promise. However, treatment strategies involving MEK inhibition in combination with other targeted therapies in other oncogene-driven NSCLC has proven to be encouraging. For example, MEK inhibition - when combined with BRAF inhibition, - has shown strong anti-tumor activity in BRAF V600 mutated NSCLC. In this review, recent data on MEK inhibitor strategies in NSCLC are summarized. Furthermore, ongoing early phase trials investigating MEK inhibitor combination therapy with immunotherapy, chemotherapy and other oncogene drivers are highlighted. These and other studies could help inform future rational combination strategies of MEK-ERK inhibition in oncogene-driven NSCLC.

Ononin promotes radiosensitivity in lung cancer by inhibiting HIF-1α/VEGF pathway

BackgroundIn our previous study, we provided evidence that Astragalus mongholicus Bunge(AM) and its extracts possess a protective capability against radiation-induced damage, potentially mediated through the reduction of reactive oxygen species (ROS) and nitric oxide (NO). However, we were pleasantly surprised to discover during our experimentation that AM not only offers protection against radiation damage but also exhibits a radiation sensitization effect. This effect may be attributed to a specific small molecule present in AM known as ononin. Currently, radiation sensitizers are predominantly found in nitrazole drugs and nanomaterials, with no existing reports on the radiation sensitization properties of ononin, nor its underlying mechanism. PurposeThis study aims to investigate the sensitization effect of the small molecule ononin derived from AM on lung cancer radiotherapy, elucidating its specific molecular mechanism of action. Additionally, the safety profile of combining astragalus small molecule ononin with radiation therapy will be evaluated. MethodsThe effective concentration of ononin was determined through cell survival experiments, and the impact of ononin combined with varying doses of radiation on lung cancer cells was observed using CCK-8 and cell cloning experiments. The apoptotic effect of ononin combined with radiation on lung cancer cells was assessed using Hochester staining, flow cytometry, and WB assay. Additionally, WB and immunofluorescence analysis were conducted to investigate the influence of ononin on HIF-1α/VEGF pathway. Furthermore, Molecular Dynamics Simulation was employed to validate the targeted binding ability of ononin and HIF-1α. A lung cancer cell line was established to investigate the effects of knockdown and overexpression of HIF-1α. Subsequently, the experiment was repeated using tumor bearing nude mice and C57BL/6 mouse models in an in vivo study. Tumor volume was measured using a vernier caliper, while HE, immunohistochemistry, and immunofluorescence techniques were employed to observe the effects of ononin combined with radiation on tumor morphology, proliferation, and apoptosis. Additionally, Immunofluorescence was employed to examine the impact of ononin on HIF-1α/VEGF pathway in vivo, and its effect on liver function in mice was assessed through biochemistry analysis. ResultsAt a concentration of 25 μM, ononin did not affect the proliferation of lung epithelial cells but inhibited the survival of lung cancer cells. In vitro experiments demonstrated that the combination of ononin and radiation could effectively inhibit the growth of lung cancer cells, induce apoptosis, and suppress the excessive activation of the Hypoxia inducible factor 1 alpha/Vascular endothelial growth factor pathway. In vivo experiments showed that the combination of ononin and radiation reduced the size and proliferation of lung cancer tumors, promoted cancer cell apoptosis, mitigated abnormal activation of the Hypoxia inducible factor 1 alpha pathway, and protected against liver function damage. ConclusionThis study provides evidence that the combination of AM and its small molecule ononin can enhance the sensitivity of lung cancer to radiation. Additionally, it has been observed that this combination can specifically target HIF-1α and exert its effects. Notably, ononin exhibits the unique ability to protect liver function from damage while simultaneously enhancing the tumor-killing effects of radiation, thereby demonstrating a synergistic and detoxifying role in tumor radiotherapy. These findings contribute to the establishment of a solid basis for the development of novel radiation sensitizers derived from traditional Chinese medicine.

USP7 promotes non-small-cell lung cancer cell glycolysis and survival by stabilizing and activating c-Abl.

Abelson tyrosine kinase (c-Abl) is frequently mutated and highly expressed, and promotes non-small-cell lung cancer (NSCLC) survival, metastasis and tumorigenesis. c-Abl could also be modified through ubiquitination, but the underlying mechanism is not well understood. Mass spectrometry assays were performed to search c-Abl deubiquitination enzymes. The molecular mechanism was determined using Co-IP assays, pull-down assays, Western blotting upon gene knockdown or overexpression. Cell lines and animal models were used to investigate the role of c-Abl and USP7 in NSCLC. EdU staining assay and Transwell assay were performed to evaluate the proliferation and migration ability of NSCLC cells, respectively. Ubiquitin-specific protease 7 (USP7) is found to upregulate c-Abl via the deubiquitinase screen. USP7 interacts with c-Abl and decreases its K48-linked polyubiquitination, thereby increasing the stability of c-Abl. In addition to the wild-type one, c-Abl mutants can also be deubiquitinated and stabilized by USP7. Moreover, USP7 promotes c-Abl accumulation in cytoplasm by increasing its binding to 14-3-3α/β and activates the oncogenic c-Abl signalling pathway. Furthermore, the USP7/c-Abl axis promotes NSCLC cell glycolysis by direct phosphorylating and stabilizing hexokinase-2 (HK2). Knockdown of USP7 or c-Abl suppresses NSCLC cell glycolysis and reduces lactate production. Further studies revealed that overexpression of USP7 facilitates NSCLC cell growth and metastasis as well as xenograft growth in nude mice, while these activities are suppressed with USP7 or c-Abl being knocked down. USP7 is a deubiquitinase of c-Abl and upregulates its oncogenic activity. USP7 promotes NSCLC cell metabolism by activating c-Abl and HK2. Targeting the USP7/c-Abl/HK2 axis might be a potential strategy to the precision therapy of NSCLC.

Abstract C040: Discovery and development of novel ATG13 degrading compounds that inhibit autophagy and treat Non-Small Cell Lung Cancer

Abstract Autophagy is the process by which a cell maintains homeostasis by removing and recycling cytoplasmic debris. Autophagy provides lung cancer cells with essential nutrients for their increased proliferation and metabolism and aids in survival during anti-cancer treatments. CRISPR knockout or siRNA knockdown of the autophagy protein ATG13 inhibits autophagy and reduces viability of non-small cell lung cancer (NSCLC) cell lines. These data show that ATG13 is essential for autophagy and essential for lung cancer cell survival, making it a viable therapeutic target for cancer treatment. To identify compounds that degrade ATG13 and inhibit autophagy, we established a high-throughput screening (HTS) compatible Nano-Glo HiBiT assay where endogenous ATG13 was labeled on the C-terminus with HiBiT peptide via CRISPR. Optimization of this assay allowed for a signal to background Z’ factor of 0.71 and confirmed a positive control compound that induced up to 50% ATG13 degradation, thus indicating that this assay was suitable for compound screening. Currently, over 50,000 compounds from a variety of libraries have been screened in 1536-well format and 15 positive hits for ATG13 degradation have been identified. A series of counter-screens and secondary assays including In Cell Western Blot and Protein Thermal Shift assays will be used to confirm these hits. At the end of this testing funnel, we will have characterized novel compounds that degrade ATG13 and inhibit autophagy. These hits will provide a starting point for further chemical optimization to provide lead ATG13 degraders to evaluate in advanced preclinical proof-of concept studies of lung cancer. Citation Format: Patrick M Hagan, Atoosa Emami, Hilarie Austin, Ian Pass, Allison Limpert, Douglas Sheffler, Nicholas Cosford. Discovery and development of novel ATG13 degrading compounds that inhibit autophagy and treat Non-Small Cell Lung Cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C040.

Invitro anticancer effect of azithromycin targeting hypoxic lung cancer cells via the inhibition of mitophagy.

Solid tumors are predisposed to hypoxia, which induces tumor progression, and causes resistance to treatment. Hypoxic tumor cells exploit auto- and mitophagy to facilitate metabolism and mitochondrial renewal. Azithromycin (AZM), a widely used macrolide, inhibits autophagy in cancer cells. The aim of the present study was to determine whether AZM targeted hypoxic cancer cells by inhibiting mitophagy. Lung cancer cell lines (A549, H1299 and NCI-H441) were cultured for up to 72 h under normoxic (20% O2) or hypoxic (0.3% O2) conditions in the presence or absence of AZM (≤25 µM), and the cell survival, autophagy flux and mitophagy flux were evaluated. AZM treatment reduced cell survival under hypoxic conditions, caused mitolysosome dysfunction with raised lysosomal pH and impaired the efficient removal of hypoxia-damaged mitochondria, eventually inducing apoptosis in the cancer cells. The cytotoxic effect of AZM under hypoxic conditions was abolished in mitochondria-deficient A549 cells (ρ° cells). The present study demonstrated that AZM reduced lung cancer cell survival under hypoxic conditions by interfering with the efficient removal of damaged mitochondria through mitophagy inhibition. Thus, AZM may be considered as a promising anticancer drug that targets the mitochondrial vulnerability of hypoxic lung cancer cells.

A Polyherbal Formulation Habb-e-Ustukhuddus Induces Apoptosis and Inhibits Cell Migration in Lung and Breast Cancer Cells without Any Toxicity in Mice.

A polyherbal medicine, Habb-e-Ustukhuddus (HU), is used for its anti-inflammatory properties. However, the anticancer and chemopreventive properties of HU were not known, and Therefore, investigated in the present study. Cancer cells were treated with 50-400 µg/ml HU and MTT, trypan blue, and clonogenic assays were performed. Propidium iodide (PI) staining, annexin V-FITC assay, and JC-1 staining were done for cell cycle progression, apoptosis, and mitochondrial membrane potential, respectively, using flow cytometry. Immunoblotting, cell migration and invasion assays were performed. Chemical characterization of HU was done through GC-MS and HPLC analyses. C57BL/6 mice were used to assess the in vivo toxicity of HU. While evaluating the anticancer activity, the methanolic extract of HU (50-400 µg/ml) strongly inhibited the growth and survival (P<0.05-0.001) of lung and breast cancer cells and increased the cell population in the sub-G1 phase of the cell cycle. HU caused apoptotic death of cancer cells (P<0.05-0.001), which was associated with the depolarization of mitochondrial membrane potential (Δψ) (P<0.001) and an increase in Bax to Bcl-2 protein ratio. Further, HU inhibited the invasion and migration of cancer cells, which was accompanied by an increase in the epithelial marker, E-cadherin, and a decrease in the mesenchymal marker, vimentin. The HU characterization by GC-MS and HPLC analyses showed the abundance of bioactive compounds including flavonoids and alkaloids. In the chemopreventive study, the oral administration of methanolic extract of the formulation HU (50 and 100 mg/kg body weight) to mice did not cause any toxicity and significantly increased the specific activities of hepatic drug metabolizing phase I and phase II enzymes, which suggested for its detoxification potential of xenobiotic compounds. Together, these results demonstrated the anticancer potential HU, without any apparent toxicity in mice, and thus HU could be further explored for its clinical utility in cancer control.

Genomics-based screening of novel therapeutic targets and biomarkers for lung cancer.

e15093 Background: Since the number of lung cancer patients who show objective response to standard treatments is still limited, development of new anti-cancer agents with minimum risk of side effects and specific cancer biomarkers is urgently required. Methods: We have been screening new therapeutic targets and their companion biomarkers for lung cancer as follows; i) To identify overexpressed genes in lung cancers by the gene expression profile analysis, ii) To verify the candidate genes for their scarce expression in normal tissues, iii) To validate the clinicopathological importance of their protein expression by tissue microarray covering hundreds of lung cancers, and iv) To characterize their function for the growth and/or survival of lung cancer cells by siRNAs. Results: We identified dozens of candidate oncoproteins and selected a lung cancer cell division-associated protein 1 (LCDAP1). Immunohistochemical analysis showed that LCDAP1 was expressed in 171 of 267 (64%) non-small cell lung cancer (NSCLC) tissues but not in normal lung epithelia. LCDAP1 expression was significantly associated with poor prognosis for NSCLC patients. To investigate its function, we screened LCDAP1-binding protein in lung cancer cells and found an interaction of LCDAP1 with a member of 5'-to-3' DNA helicase that was also up-regulated in lung cancer cells. Knockdown of either of LCDAP1 or its binding partner expression with siRNAs significantly inhibited the growth of cancer cells. Conclusions: Our genomics-based screening could be useful to develop diagnostic and prognostic biomarkers as well as therapeutic targets for small molecules, monoclonal antibodies, and nucleic acid drugs against lung cancer.

The deubiquitinase OTUB1 governs lung cancer cell fitness by modulating proteostasis of OXPHOS proteins

Aerobic glycolysis is a hallmark of cancer development, but this dogma has been challenged by reports showing a key role of oxidative phosphorylation (OXPHOS) in cancer cell survival. It has been proposed that increased levels of intramitochondrial proteins in cancer cells are associated with high OXPHOS activity and increased sensitivity to OXPHOS inhibitors. However, the molecular mechanisms leading to the high expression of OXPHOS proteins in cancer cells remain unknown. Multiple proteomics studies have detected the ubiquitination of intramitochondrial proteins, suggesting the contribution of the ubiquitin system to the proteostatic regulation of OXPHOS proteins. Here, we identified the ubiquitin hydrolase OTUB1 as a regulator of the mitochondrial metabolic machinery essential for lung cancer cell survival. Mitochondria-localized OTUB1 modulates respiration by inhibiting K48-linked ubiquitination and turnover of OXPHOS proteins. An increase in OTUB1 expression is commonly observed in one-third of non-small-cell lung carcinomas and is associated with high OXPHOS signatures. Moreover, OTUB1 expression highly correlates with the sensitivity of lung cancer cells to mitochondrial inhibitors.

In vitro differences analysis in proliferation and drug sensitivity of tumor-associated fibroblasts from different regions of FDG metabolism to non-small-cell lung carcinoma

Objective: 18F-FDG PET can directly reflect the glucose metabolism level of cells from the molecular level. Tumor-associated fibroblasts, as the natural physiological barrier of tumors, support and protect the survival of non-small cell lung cancer cells. This study will further observe the differences in the supporting effects of CAFs from different regions of 18F-FDG PET metabolism on cancer cells. Methods: Biopsy tissues were collected from PET/CT patients diagnosed with NSCLC for the first time in the Department of Nuclear Medicine, The First Hospital of Shanxi Medical University. The locations of puncture were all selected in areas with high metabolism of tumor. Primary CAFs were cultured by tissue adhesion method. A549 acts as EGFR (-) tumor cells, while PC9 acts as EGFR (+) tumor cells. CAFs conditional medium was collected to induce the culture of A549 and PC9 cells, labeled as A549high/low and PC9high/low, respectively. CCK was used to measure cancer cell proliferation rate, Transwell was used to measure cancer cell invasiveness, and scratch assay was used to measure cancer cell migration. The cells were treated with cisplatin and gefitinib respectively to observe the resistance of the cells. Results: Tissues of two NSCLC patients with SUVmax were 1.25 and 11.15, respectively. The conditioned medium induced cancer cells for 48 hours. CCK (48h) results showed that SUVhigh-derived CAFs could promote the proliferation of two types of cancer cells more than SUVlow-derived CAFs. The wound healing experiment showed that A549high had completed the healing at 72h, followed by low metabolism area, and A549 was the worst. The results for PC9 cells were similar to those for A549. Transwell experiment showed that PC9high/ low showed obvious difference in invasiveness at 24 hours, and the difference was more significant at 48 hours. A549 also showed difference in invasiveness, but the difference was relatively weak. When the corresponding cells were further treated with cisplatin or gefitinib, the proliferation rate of A549high/low cells was significantly different in the gradient range of high cisplatin concentration, while the proliferation rate of PC9high/low cells was significantly different in the low-medium gefitinib concentration. Conclusion: The regions of FDG metabolism difference shown in PET support the reverse warburg effect. As a physiological barrier to tumors, CAFs is one of the key factors that promote the occurrence, metastasis and drug resistance of lung cancer. National Natural Science Foundation of China (Grant number:81971655) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The UBE2C/CDH1/DEPTOR axis is an oncogene and tumor suppressor cascade in lung cancer cells.

Ubiquitin-conjugating enzyme E2C (UBE2C) mediates ubiquitylation chain formation via the K11 linkage. While previous in vitro studies showed that UBE2C plays a growth-promoting role in cancer cell lines, the underlying mechanism remains elusive. Still unknown is whether and how UBE2C plays a promoting role in vivo. Here we report that UBE2C was indeed essential for growth and survival of lung cancer cells harboring Kras mutations, and UBE2C was required for KrasG12D-induced lung tumorigenesis, since Ube2c deletion significantly inhibited tumor formation and extended the lifespan of mice. Mechanistically, KrasG12D induced expression of UBE2C, which coupled with APC/CCDH1 E3 ligase to promote ubiquitylation and degradation of DEPTOR, leading to activation of mTORC signaling. Importantly, DEPTOR levels fluctuated during cell cycle progression in a manner dependent on UBE2C and CDH1, indicating their physiological connection. Finally, Deptor deletion fully rescued the tumor inhibitory effect of Ube2c deletion in the KrasG12D lung tumor model, indicating a causal role of Deptor. Taken together, our study shows that the UBE2C/CDH1/DEPTOR axis forms an oncogene and tumor suppressor cascade that regulates cell cycle progression and autophagy and validates UBE2C an attractive target for lung cancer associated with Kras mutations.