EGFR Activation Research Articles

In Vitro and In Silico Evaluation of Antiproliferative Activity of New Isoxazolidine Derivatives Targeting EGFR: Design, Synthesis, Cell Cycle Analysis, and Apoptotic Inducers.

A series of novel enantiopure isoxazolidine derivatives were synthesized and evaluated for their anticancer activities against three human cancer cell lines such as human breast carcinoma (MCF-7), human lung adenocarcinoma (A-549), and human ovarian carcinoma (SKOV3) by employing MTT assay. The synthesized compounds were characterized by NMR and elemental analysis. Results revealed that all the synthesized compounds displayed significant inhibition towards the tested cell lines. Among them, 2g and 2f, which differ only by the presence of an ester group at the C-3 position and small EDG (methyl) at the C-5 position of the phenyl ring (2g), were the most active derivatives in attenuating the growth of the three cells in a dose-dependent manner. The IC50 for 2g were 17.7 ± 1 µM (MCF-7), 12.1 ± 1.1 µM (A-549), and 13.9 ± 0.7 µM (SKOV3), and for 2f were 9.7 ± 1.3µM (MCF-7), 9.7 ± 0.7µM (A-549), and 6.5 ± 0.9µM (SKOV3), respectively, which were comparable to the standard drug, doxorubicin. The enzymatic inhibition of 2f and 2g against EGFR afforded good inhibitory activity with IC50 of 0.298 ± 0.007 μM and 0.484 ± 0.01 µM, respectively, close to the positive control, Afatinib. Compound 2f arrested the cell cycle in the S phase in MCF-7 and SKOV3 cells, and in the G2/M phase in the A549 cell; however, 2g induced G0/G1 phase cell cycle arrest, and inhibited the progression of the three cancer cells, together with significant apoptotic effects. The docking study of compounds 2f and 2g into EGFR ATP-active site revealed that it fits nicely with good binding affinity. The pharmacokinetic and drug-likeness scores revealed notable lead-like properties. At 100 ns, the dynamic simulation investigation revealed high conformational stability in the EGFR binding cavity.

Switching mechanism from AR to EGFR signaling via 3-O-sulfated heparan sulfate in castration-resistant prostate cancer

Androgen deprivation therapy is given to suppress prostate cancer growth; however, some cells continue to grow hormone-independently as castration-resistant prostate cancer (CRPC). Sulfated glycosaminoglycans promote ligand binding to receptors as co-receptors, but their role in CRPC remains unknown. Using the human prostate cancer cell line C4-2, which can proliferate in hormone-dependent and hormone-independent conditions, we found that epidermal growth factor (EGF)-activated EGFR–ERK1/2 signaling via 3-O-sulfated heparan sulfate (HS) produced by HS 3-O-sulfotransferase 1 (HS3ST1) is activated in C4-2 cells under hormone depletion. Knockdown of HS3ST1 in C4-2 cells suppressed hormone-independent growth, and inhibited both EGF binding to the cell surface and activation of EGFR–ERK1/2 signaling. Gefitinib, an EGFR inhibitor, significantly suppressed C4-2 cell proliferation and growth of a xenografted C4-2 tumor in castrated mouse. Collectively, our study has revealed a mechanism by which cancer cells switch to hormone-independent growth and identified the key regulator as 3-O-sulfated HS.

Lysine methylation promotes NFAT5 activation and determines temozolomide efficacy in glioblastoma

Temozolomide (TMZ) therapy offers minimal clinical benefits in patients with glioblastoma multiforme (GBM) with high EGFR activity, underscoring the need for effective combination therapy. Here, we show that tonicity-responsive enhancer binding protein (NFAT5) lysine methylation, is a determinant of TMZ response. Mechanistically, EGFR activation induces phosphorylated EZH2 (Ser21) binding and triggers NFAT5 methylation at K668. Methylation prevents NFAT5 cytoplasm interaction with E3 ligase TRAF6, thus blocks NFAT5 lysosomal degradation and cytosol localization restriction, which was mediated by TRAF6 induced K63-linked ubiquitination, resulting in NFAT5 protein stabilization, nuclear accumulation and activation. Methylated NFAT5 leads to the upregulation of MGMT, a transcriptional target of NFAT5, which is responsible for unfavorable TMZ response. Inhibition of NFAT5 K668 methylation improved TMZ efficacy in orthotopic xenografts and patient-derived xenografts (PDX) models. Notably, NFAT5 K668 methylation levels are elevated in TMZ-refractory specimens and confer poor prognosis. Our findings suggest targeting NFAT5 methylation is a promising therapeutic strategy to improve TMZ response in tumors with EGFR activation.

Budding uninhibited by benzimidazoles-1 (BUB1) regulates EGFR signaling by reducing EGFR internalization.

EGFR signaling initiates upon ligand binding which leads to activation and internalization of the receptor-ligand complex. Here, we evaluated if BUB1 impacted EGFR signaling by regulating EGFR receptor internalization and activation. BUB1 was ablated genomically (siRNA) or biochemically (2OH-BNPP1) in cells. EGF ligand was used to initiate EGFR signaling while disuccinimidyl suberate (DSS) was used for cross linking cellular proteins. EGFR signaling was measured by western immunoblotting and receptor internalization was evaluated by fluorescent microscopy (pEGFR (pY1068) colocalization with early endosome marker EEA1). siRNA mediated BUB1 depletion led to an overall increase in total EGFR levels and more phospho-EGFR (Y845, Y1092, and Y1173) dimers while the amount of total EGFR (non-phospho) dimers remained unchanged. BUB1 inhibitor (BUB1i) decreased EGF mediated EGFR signaling including pEGFR Y845, pAKT S473 and pERK1/2 in a time dependent manner. Additionally, BUB1i also reduced EGF mediated pEGFR (Y845) dimers (asymmetric dimers) without affecting total EGFR dimers (symmetric dimers) indicating that dimerization of inactive EGFR is not affected by BUB1. Furthermore, BUB1i blocked EGF mediated EGFR degradation (increase in EGFR half-life) without impacting half-lives of HER2 or c-MET. BUB1i also reduced co-localization of pEGFR with EEA1 positive endosomes suggesting that BUB1 might modulate EGFR endocytosis. Our data provide evidence that BUB1 protein and its kinase activity may regulate EGFR activation, endocytosis, degradation, and downstream signaling without affecting other members of the receptor tyrosine kinase family.

#5217 PROTOCOL AND PRELIMINARY RESULTS OF DAPAGLIFLOZIN IN INACTIVE LUPUS NEPHRITIS CROSS-OVER RANDOMIZED TRIAL

Abstract Background and Aims Sodium-glucose co-transporter 2 (SGLT2) inhibitors slow the progression of chronic kidney disease (CKD) with and without type 2 diabetes. Lupus nephritis (LN) patients under immunosuppression were excluded from the most important trials with SGLT2 inhibitors. Thus, efficacy and tolerance of these drugs are unknown in such patients. The present trial will assess the effect of Dapagliflozin in patients with inactive Lupus Nephritis with residual proteinuria. Method For this cross-over randomized trial, we will include adult patients with LN class III, IV (+/-V) without active nephritis but with proteinuria > 500mg/24h or UPC > 200mg/g and eGFR ≥ 20ml/min, in the maintenance treatment. RAAS inhibition should be stable for at least four weeks before the randomization. We will exclude patients with other etiologies of CKD, those with active LN lesions on the recent biopsy (AI>2), use of induction therapy in the last 12 months (Cyclophosphamide, Mycophenolate Mofetil >2 g/day and Calcineurin inhibitors) and prednisone dose ≥ 20 mg/day. Due to safety issues, we will exclude patients with recurrent urinary infections (>3 times/year). They will be randomized to receive Dapagliflozin 10mg on top of standard of care therapy or not. After 24 weeks the groups will be switched and those without Dapagliflozin will receive it for the next 24 weeks. Primary endpoint will be reduction of proteinuria compared to baseline at 6 and 12 months. Secondary endpoints will include sustained reduction of eGFR > 30%; changes in weight and blood pressure compared to baseline; and number of infections on Dapagliflozin treatment versus exclusive standard of care therapy. The sample size was calculated for 28 patients enrolled providing 80% power to detect a 25% relative risk reduction in proteinuria (α level of 0.05). Results From 85 screened class III, IV (+/- V) LN patients under maintenance therapy, we excluded 65 due to active nephritis, low proteinuria or low eGFR. Until now we included 17 patients that were randomized 1:1 to start the treatment with Dapagliflozin on top of standard care or remain with the usual therapy for 24 weeks. Patients’ baseline characteristics are described in Table 1. All patients randomized were using Mycophenolate Mofetil ≤2 g/day and RAAS inhibition and 14 of them were receiving Hydroxychloroquine. Conclusion We expect that the present trial will determine whether the SGLT2 inhibitor Dapagliflozin, added to LN maintenance therapy, could safely reduce the residual proteinuria of inactive LN patients.

#5128 PREDICTIVE FACTORS OF RENAL RECOVERY AND END-STAGE KIDNEY DISEASE IN PATIENTS WITH SEVERE ANCA-ASSOCIATED VASCULITIS WITH GLOMERULONEPHRITIS

Abstract Background and Aims A significant number of patients with anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis (AAV) with glomerulonephritis (AAV-GN) still progress to end-stage kidney disease (ESKD, eGFR<15mL/min/1.73m2) despite advances in remission-induction treatment. Method A retrospective cohort study on MPO- or PR3-ANCA positive patients with AAV (MPA or GPA) and ESKD at presentation. Renal recovery, dialysis discontinuation and maintenance in ESKD after standard remission-induction, with or without the use of PLEX were compared. Results We analyzed 166 patients with biopsy proven active kidney involvement and eGFR <15mL/min/1.73m2 at the time of AAV-GN diagnosis. Patients received glucocorticoids with CYC (n = 84) or with RTX (n = 72) for remission-induction, and 49 also received PLEX. The predictors for renal recovery were erythrocyte sedimentation rate, SCr at diagnosis and minimal or mild chronicity changes. We analyzed 71 patients who started dialysis with or without PLEX within 4 weeks from AAV-GN diagnosis. The predictors for dialysis discontinuation were minimal chronicity changes in kidney biopsy at the time of diagnosis (OR 6.138, [95%CI 1.389-27.118],p = 0.017) and focal glomerular involvement (OR 5.017,[95%CI 1.287-19.567],p = 0.020). Predictors for maintenance in ESKD at 12 months included higher serum creatinine (SCr) at the time of diagnosis (IRR 1.086, [95%CI 1.005-1.173],p = 0.037), moderate (IRR 3.797,[95%CI 1.090-13.225],p = 0.036), or severe chronicity changes in kidney biopsy (IRR 5.883,[95%CI 1.542–22.439],p = 0.009). Conclusion In our cohort, kidney recovery, dialysis discontinuation, and maintenance of ESKD in patients with AAV-GN and eGFR<15mL/min/1.73m2 depended on SCr and histologic findings on kidney biopsies at the time of diagnosis and was not affected by the addition of PLEX.

Synthesis of novel mono- and bis-pyrazolylthiazole derivatives as anti-liver cancer agents through EGFR/HER2 target inhibition

3-Bromoacetyl-4-(2-naphthoyl)-1-phenyl-1H-pyrazole (6) was synthesized from 2-acetylnaphthalene and was used as a new key building block for constructing the title targets. Thus, the reaction of 6 with the thiosemicarbazones 7a–d and 9–11 afforded the corresponding simple naphthoyl-(3-pyrazolyl)thiazole hybrids 8a–d and 12 ~ 14. The symmetric bis-(2-naphthoyl-pyrazol-3-yl)thiazol-2-yl)hydrazono)methyl)phenoxy)alkanes 18a-c and 21a-c were similarly synthesized from reaction of 6 with the appropriate bis-thiosemicarbazones 17a-c and 19a-c, respectively. The synthesized two series of simple and symmetrical bis-molecular hybrid merging naphthalene, thiazole, and pyrazole were evaluated for their cytotoxicity. Compounds 18b,c and 21a showed the most potent cytotoxicity (IC50 = 0.97–3.57 µM) compared to Lapatinib (IC50 = 7.45 µM). Additionally, they were safe (non-cytotoxic) against the THLE2 cells with higher IC50 values. Compounds 18c exhibited promising EGFR and HER-2 inhibitory activities with IC50 = 4.98 and 9.85 nM, respectively, compared to Lapatinib (IC50 = 6.1 and 17.2 nM). Apoptosis investigation revealed that 18c significantly activated apoptotic cell death in HepG2 cells, increasing the death rate by 63.6-fold and arresting cell proliferation at the S-phase. Compound 18c upregulated P53 by 8.6-fold, Bax by 8.9-fold, caspase-3,8,9 by 9, 2.3, and 7.6-fold, while it inhibited the Bcl-2 expression by 0.34-fold. Thereby, compound 18c exhibited promising cytotoxicity against EGFR/HER2 inhibition against liver cancer.

Enteroaggregative Escherichia coli induced activation of epidermal growth factor receptor contributes to IL-8 secretion by cultured human intestinal epithelial cells

Enteroaggregative Escherichia coli (EAEC) has been identified as a new enteropathogen that causes acute and chronic diarrhea in children and travelers. One defining aspect of EAEC-pathogenesis is the induction of an inflammatory response in intestinal epithelium. In this study, we have found that EAEC-induced EGFR activation in human small intestinal and colonic epithelial was attenuated in the presence of a specific inhibitor of EGFR (Tyrphostin AG1478). Further, the aggregative stacked-brick type of adherence of this organism to both the cell lines and this pathogen-induced cytoskeletal rearrangement of these cells was also reduced in the presence of Tyrphostin AG1478. Moreover, EAEC-induced activation of downstream effectors (ERK-1/2, PI3K and Akt) of EGFR mediated cell signaling pathways were found to be suppressed in the presence of EGFR inhibitor. A decrease in IL-8 response in EAEC infected both the cell types were also noted in the presence of specific inhibitors of these downstream effectors, transcription factors and Tyrphostin AG1478. We propose that EAEC-induced activation of EGFR is quintessential for stacked-brick adherence of EAEC to human intestinal epithelial cells, their cytoskeletal rearrangements and stimulation of ERK-1/2 and PI3K/Akt mediated signal transduction pathways, resulting in the activation of NF-κB, AP-1, STAT-3 and finally IL-8 secretion by these cells.

Pemetrexed induces ROS generation and cellular senescence by attenuating TS-mediated thymidylate metabolism to reverse gefitinib resistance in NSCLC.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) are strongly recommended for non-small-cell lung cancer (NSCLC) patients harbouring active EGFR mutations, while drug resistance makes exploring resistance mechanisms and seeking effective therapeutic strategies urgent endeavours. Thymidylate synthetase (TYMS or TS) is a dominant enzyme in thymidylate nucleotide metabolism. In this study, we found a positive correlation between TS expression and overall survival (OS) and disease-free survival (DFS) in lung adenocarcinoma. The examination of gene sets from 140 NSCLC patients received EGFR-TKI therapy demonstrated a negative correlation between high TS expression and the efficacy of EGFR-TKI therapy. 24 tissue specimens from NSCLC patients exhibited upregulated TS mRNA expression in NSCLC patients resistant to gefitinib. The NSCLC cell PC9 and HCC827 sensitive to gefitinib and relatively resistant PC9/GR and HCC827/GR cells were used to demonstrate the knockdown of TS restored the sensitivity of resistant cells to gefitinib. Furthermore, pemetrexed effectively suppressed TS-mediated thymidylate metabolism and induced ROS generation, DNA damage and cellular senescence, thereby hampering cancer progression and restoring sensitivity to gefitinib. Our findings illuminate the potential mechanism of TS-triggered gefitinib resistance and indicate inhibition of TS by pemetrexed can potentiate the effect of gefitinib in NSCLC. Pemetrexed combined with gefitinib has potent anti-progression potential in gefitinib-resistant NSCLC. This study suggests that NSCLC patients with both high TS expression and EGFR-driving mutations might benefit more from a combination strategy of EGFR-TKI and pemetrexed-based chemotherapy than EGFR-TKI monotherapy, which has profound clinical implications and therapeutic value.

Abstract B076: IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer

Abstract Background: Castration-resistant prostate cancer (CRPC) is an incurable disease and a leading cause of cancer death in men worldwide. Olaparib (Lynparza) was among the first PARP inhibitors (PARPi) approved for the treatment of CRPC tumors harboring DNA repair defects. However, clinical resistance to PARPi’s has been documented. The mechanisms underlying resistance to PARPi’s remain elusive. To study acquired resistance, we developed olaparib-resistant LN-OlapR and 2B-OlapR cell lines generated through chronic olaparib treatment of the olaparib-sensitive cell lines LNCaP and C4-2B, respectively. RNA-seq revealed IGFBP3 is overexpressed in both OlapR cell lines. IGFBP3 overexpression is correlated with poor clinical outcome and is thought to participate in DNA repair pathways. IGFBP3 plays a key role in nonhomologous end joining (NHEJ) repair through a ternary complex with EGFR and DNA-PKcs. The IGFBP3/EGFR signaling axis is thought to modulate NHEJ repair and could have implications for PARPi sensitivity. We hypothesize that increased IGFBP3 expression promotes PARPi resistance by enhancing DNA repair capacity. Methods: RNA-sequencing and gene set enrichment analysis were used to determine the expression profile changes in resistant cells compared to parental cells. Real time PCR and western blots confirmed the expression of DNA damage repair genes such as γH2AX, EGFR, and DNA-PKcs. ELISA was used to determine IGFBP3 secretion. RNAi was used to inhibit IGFBP3 and EGFR expression. Gefitinib was used to inhibit EGFR activity. Cell viability assays were used to assess cell growth. Results: Transcriptomic profiling revealed that IGFBP3 is highly expressed in resistant models. We verified increased levels of IGFBP3 RNA and protein in both OlapR models. We found that RNAi inhibition of IGFBP3 increases γH2AX and cleaved-PARP protein levels in the resistant models, which suggests accumulation of DNA double strand breaks (DSBs) leading to genomic instability and cell death. We discovered increased phosphorylation of EGFR and DNA-PKcs in the resistant cells. Furthermore, silencing/inhibiting IGFBP3 and EGFR reduces OlapR cell viability and resensitizes resistant cells to treatment. Conclusions: Our findings demonstrated that inhibiting IGFBP3 and EGFR aids in PARPi sensitivity in the resistant setting. Future work will utilize OlapR models to study how the IGFBP3/EGFR/DNA-PKcs protein complex promotes the development of resistance. Understanding the role of IGFBP3 in PARPi resistance will enhance our ability to re-sensitize resistant CRPC to PARPi therapeutics. Citation Format: Amy R. Leslie, Allen C. Gao, Alan P. Lombard, Shu Ning. IGFBP3 promotes resistance to olaparib via modulating EGFR signaling in advanced prostate cancer [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B076.

BLU-945 monotherapy and in combination with osimertinib (OSI) in previously treated patients with advanced EGFR-mutant (EGFRm) NSCLC in the phase 1/2 SYMPHONY study.

9011 Background: Despite improved frontline OSI treatment outcomes, patients (pts) with advanced EGFRm NSCLC inevitably progress, with worse outcomes in the EGFR L858R subgroup (median PFS of 14.4 vs 21.4 mo in pts with exon 19 deletions). BLU-945 is an investigational, next-generation, oral tyrosine kinase inhibitor (TKI) that targets common EGFR-activating and T790M and C797X resistance mutations, while being selective against EGFR wild type (WT). Preclinically, BLU-945 in combination (combo) with OSI had enhanced potency on L858R and extended antitumor response durability versus OSI alone. SYMPHONY (NCT04862780) is an ongoing first-in-human phase 1/2 study of BLU-945 monotherapy (mono) or combo with OSI. Methods: In the phase 1 dose escalation, pts (aged ≥18 y; metastatic EGFRm NSCLC; ECOG PS 0–1; treated with ≥1 EGFR TKI) received BLU-945 mono starting at 25 mg QD. Pts progressing on OSI could receive BLU-945 with 80 mg OSI starting at 50% of the highest safe BLU-945 mono dose. Each dose escalation followed a Bayesian Optimal Interval design. Safety, including dose-limiting toxicities (DLT), PK, and circulating tumor DNA (ctDNA) mutational status were assessed. Results: As of Jan 6, 2023, 108 pts received BLU-945 mono (25–600 mg QD; 100–300 mg BID). Pts had a median of 3 lines of prior therapy and were genomically complex with ctDNA detectable EGFR on-target and/or off-target resistance alterations (46%) at baseline. DLTs included alanine transaminase (ALT) and aspartate transaminase (AST) elevation, hepatic cytolysis, fatigue, nausea, vomiting, and hyponatremia, occurring at doses of ≥400 mg/d. The maximum tolerated dose was 500 mg/d. The most common AEs were nausea (42%), headache (40%), increased ALT (38%), increased AST (37%), and vomiting (32%). Robust on-target EGFR activity was observed with ctDNA reduction on day 15 in 90%, 85% and 70% of EGFR T790M, C797S, and L858R alleles at ≥400 mg/d doses, respectively. At ≥400 mg/d, 48% had tumor shrinkage, including partial responses (PRs). Twenty-five pts received BLU-945 (200–400 mg QD; 100–200 mg BID) combo with OSI. Pts had a median of 2 lines of prior therapy. The most common combo AEs were fatigue (36%), diarrhea (32%), headache (32%), and nausea (28%). Other EGFR WT AEs were dry skin (20%) and rash (8%). One DLT (Grade 4 pneumonitis) was reported in the BLU-945 300 mg QD with OSI group. Tumor reductions, including PRs in 2 pts progressing on OSI, were observed at ≥300 mg/d. Dose escalation is ongoing. Conclusions: BLU-945 mono and combo with OSI were generally well tolerated and showed robust on-target EGFR ctDNA reduction, with tumor shrinkage in genomically heterogeneous, heavily pretreated pts. Combo showed responses at BLU-945 doses lower than in mono, consistent with additive benefit. The combo safety profile and on-target activity provide rationale for further development in front line. Clinical trial information: NCT04862780 .

Integration of Multi-omic Data in a Molecular Tumor Board Reveals EGFR-Associated ALK-Inhibitor Resistance in a Patient With Inflammatory Myofibroblastic Cancer.

Inflammatory myofibroblastic tumors (IMTs) are intermediate-grade mesenchymal neoplasms commonly characterized by chromosomal rearrangements causing constitutive activation of anaplastic lymphoma kinase (ALK) and/or ALK mutations causing reduced sensitivity to ALK tyrosine kinase inhibitors (TKI). We present a patient with an IMT who initially responded to first-line alectinib, but who later suffered disease relapse and presently survives with moderate residual disease after receiving second-line lorlatinib. Biopsy specimens were analyzed using next generation sequencing (DNA-seq and RNA-seq) and reverse phase protein microarray (RPPA) as part of an institutional Molecular Tumor Board (MTB) study. An EML4-ALK rearrangement and EGFR activation (pEGFRY1068) were present in both the primary and recurrent tumors, while a secondary ALK I1171N mutation was exclusive to the latter. EGFR signaling in the background of a secondary ALK mutation is correlated with reduced ALK TKI sensitivity in vitro, implicating an important mechanism of drug resistance development in this patient. The RPPA results also critically demonstrate that ALK signaling (ALKY1604) was not activated in the recurrent tumor, thereby indicating that standard-of-care use of third- or fourth-line ALK TKI would not likely be efficacious or durable. These results underscore the importance of real-time clinical integration of functional protein drug target activation data with NGS in the MTB setting for improving selection of patient-tailored therapy.

Multiplexed imaging for probing RAS-RAF interactions in living cells

GTP-bound RAS interacts with its protein effectors in response to extracellular stimuli, leading to chemical inputs for downstream pathways. Significant progress has been made in measuring these reversible protein-protein interactions (PPIs) in various cell-free environments. Yet, acquiring high sensitivity in heterogeneous solutions remains challenging. Here, using an intermolecular fluorescence resonance energy transfer (FRET) biosensing approach, we develop a method to visualize and localize HRAS-CRAF interactions in living cells. We demonstrate that the EGFR activation and the HRAS-CRAF complex formation can be concurrently probed in a single cell. This biosensing strategy discriminates EGF-stimulated HRAS-CRAF interactions at the cell and organelle membranes. In addition, we provide quantitative FRET measurements for assessing these transient PPIs in a cell-free environment. Finally, we prove the utility of this approach by showing that an EGFR-binding compound is a potent inhibitor of HRAS-CRAF interactions. The outcomes of this work form a fundamental basis for further explorations of the spatiotemporal dynamics of various signaling networks.

Acacetin exerts antitumor effects on gastric cancer by targeting EGFR.

Background: Gastric cancer (GC) is a common malignant tumor with a poor prognosis. Combination treatments may prolong the survival of patients with GC. Acacetin, which is a flavonoid, exerts potent inhibitory effects on several types of cancer cells; however, the mechanisms of action remain poorly understood. Methods: Network pharmacology and RNA sequencing were used to predict the targets of acacetin, which were then verified by drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA) and molecular docking. The biological functions of acacetin in MKN45 and MGC803 cells were investigated using TUNEL assays, crystal staining and colony formation assays. The pathways affected by acacetin were verified through reverse experiments. The in vivo antitumor efficacy of acacetin was assessed in a subcutaneous xenotransplanted tumor model. Results: In this study, we identified EGFR from more than a dozen predicted targets as a protein that directly binds to acacetin. Moreover, acacetin affected the level of phosphorylated EGFR. In vitro, acacetin promoted the apoptosis of GCcells. Importantly, EGFR agonists reversed the inhibitory effects of acacetin on the STAT3 and ERK pathways. In vivo, acacetin decreased the protein levels of pEGFR in tumors, resulting in increased GC xenograft tumor regression without obvious toxicity. Conclusion: Our findings highlight EGFR as one of the direct targets of acacetin in GCcells. Acacetin inhibited the phosphatase activity of EGFR in vitro and in vivo, which played a role in the antitumor effects of acacetin. These studies provide new evidence for the use of acacetin as a potential reagent for the treatment of GC.

"Inhibitory Effect of Magnolol on Activation of EGFR L858R/T790M/G796R"

"Inhibitory Effect of Magnolol on Activation of EGFR L858R/T790M/G796R"

Antitumor effects of erlotinib in combination with berberine in A431 cells

BackgroundFirst-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as erlotinib, have been shown to target tumors with L858R (exon 21) and exon 19 deletions, resulting in significant clinical benefits. However, acquired resistance often occurs due to EGFR mutations. Therefore, novel therapeutic strategies for treatment of patients with EGFR-positive tumors are needed. Berberine (BBR) is an active alkaloid extracted from pharmaceutical plants such as Coptis chinensis. Berberine has been shown to significantly inhibit EGFR activity and mediate anticancer effects in multiple preclinical studies. We investigated whether combining BBR with erlotinib could augment erlotinib-induced cell growth inhibition of EGFR-positive cells in a mouse xenograft model.MethodsWe examined the antitumor activities and potential mechanisms of erlotinib in combination with berberine in vitro and in vivo using the MTT assay, immunoblotting, flow cytometry, and tumor xenograft models.ResultsIn vitro studies with A431 cells showed that synergistic cell growth inhibition by the combination of BBR and erlotinib was associated with significantly greater inhibition of pEGFR and pAKT, and inhibition of cyclin D and Bcl-2 expression compared to that observed in response to BBR or erlotinib alone. The efficacy of the combination treatment was also investigated in nude mice. Consistent with the in vitro results, BBR plus erlotinib significantly reduced tumor growth.ConclusionOur data supported use of BBR in combination with erlotinib as a novel strategy for treatment of patients with EGFR positive tumors.

151 TRPA1/V3-Dependent Regulation of Airway Epithelial Cell Damage and Repair Triggered by wood/Biomass Smoke Particulate

Abstract Wood/biomass smoke particulate material (WBSPM) is a pervasive environmental pollutant. Acute high-dose inhalation exposure can cause airway epithelial cell (AEC) damage and respiratory dysfunction. We hypothesized that AEC damage is limited by compensatory signaling to allow epithelial repair. RNA sequencing, proteomics, targeted interventions, and cultured human AECs treated with WBSPM and Transient Receptor Potential Ankyrin-1 (TRPA1) agonists revealed TRPA1-driven endoplasmic reticulum stress (ERS) and oxidative stress (OS) as contributory pathways to cytotoxicity. Alternatively, TRP vanilloid-3 (TRPV3) counteracted these events despite also being activated by WBSPM. Using the TRPA1 agonist AITC (and others) as a surrogate for WBSPM, morphological distortion indicative of AEC damage was observed 2-4h post-treatment; at >6h cells recovered. Strikingly, at 2h, the abundance of only 6 proteins changed including loss of fibronectin and tubulin and increased heme oxygenase 1. At 6h, 36 proteins changed, including ER chaperones and transcriptional/cell cycle regulatory proteins, OS-response, and structural/matrix proteins. Analysis of the phosphoproteome revealed changes in 2672 and 1886 unique phosphosites at 2 and 6h, attributable to PKC, p38 MAPK, EGFR, Akt and other kinase activities based on “phosphosite-GSEA” analysis. A kinase inhibitor screen linked PKC, p38 MAPK, GSK3b and ERK1/2 with cytotoxicity, while EGFR, MEK1/2, JNK1/2/3 and Akt were protective. Considering that TRPV3 expression is regulated by EGFR following WBSPM injury and TRPV3 enhanced adhesion and slowed proliferation via attenuated EGFR signaling, we propose a mechanism whereby the balance of TRPA1, TRPV3, and calcium/growth factor receptor-dependent kinase signaling coordinates WBSPM injury, compensation and repair.

Abstract A007: Proteogenomic landscape of KRASG12C lung adenocarcinomas reveals new subtypes and potential combination therapies

Abstract Despite the presence of the KRASG12C oncogene, not all patients respond to KRASG12C inhibitors (e.g., sotorasib, adagrasib) and duration of response has been variable. We hypothesized that subtypes of KRASG12C lung cancers could be responsible for such differential effects. To define subtypes, we performed targeted exon sequencing, transcriptomics, proteomics, and phosphoproteomics on 46 frozen surgically resected KRASG12C lung adenocarcinomas. We employed unbiased consensus clustering methods, pathway analysis, and PTM-SEA to identify kinase signatures from phosphoproteomics data. Transcriptomics data revealed 4 clusters. Pathway enrichment showed that gene cluster (GC) 1 was enriched for immune pathways including interferon gamma response. Epithelial-mesenchymal transition (EMT), assessed by a TGF-β gene signature, was also enriched in GC1. 100% of GC1 overlapped the Proximal-Inflammatory subtype (Wilkerson et al.) and 53% with the mesenchymal subtype (Daemen et al.). GC2 was enriched for inflammatory response and TNF-alpha signaling. GC3 represented a metabolic phenotype with enriched xenobiotic metabolism and other metabolism pathways. 83% of GC3 overlapped with the Terminal Respiratory Unit subtype (Wilkerson et al.) and 56% with the proliferative subtype (Daemen et al.). GC4 only had 5 samples and did not have any significant enrichment. We next identified four proteomic clusters with distinct biology. Protein Cluster 1 (PC1) was enriched for immune pathways, PC2 was enriched for EMT, and PC3 was enriched for TNF/NF-κβ signaling. PC4 was enriched for xenobiotic and fatty acid metabolism and had significantly more KEAP1 mutations. We observed concordance of protein based clusters with mRNA based clusters, as PC1 largely overlapped with GC1 (70%) and PC4 largely overlapped with GC3 (86%). Cell type inference using xCell largely recapitulated the immune subtypes identified by transcriptomics and proteomics. GC1/PC1 had significantly more CD8+ effector memory T-cells, CD4+ Th2 T-cells, and M1 macrophages, while GC3/PC4 had significantly less of these same cell types. Collectively, GC1/PC1 represents 43% of the cohort and was defined by enrichment of immune pathways, elevated immune populations, and significantly higher PD-L1. Finally, we leveraged the phosphoproteomics data to determine whether signaling activity differs across subtypes. Using PTM-SEA, we identified phosphoproteomic signatures of activity for 50 kinases and pathways. We identified 26% of samples (N=12) with high EGFR activity, which is known to affect sensitivity of cells to KRASG12C inhibitors. The EGFR-high samples were observed across all genomic, transcriptomic, and proteomic subtypes. Our results suggest concordance of some transcriptomic and proteomic subtypes, including an immune subtype, while a metabolic protein subtype and EGFR high signaling subtype may provide additional subclasses with potential relevance for treatment responses. Additional phosphoproteomics signatures such as PLK1 and AKT1 may identify subtypes amenable to combination therapy approaches. Citation Format: Paul A. Stewart, Hitendra Solanki, Eric Welsh, Yaakov Stern, Denis Imbody, Yonghong Zhang, Bruna Pellini, Bin Fang, Sean Yoder, Steven Eschrich, Jamie Teer, John Koomen, Eric B. Haura. Proteogenomic landscape of KRASG12C lung adenocarcinomas reveals new subtypes and potential combination therapies [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr A007.

Design, synthesis, and molecular docking studies of novel quinoxaline derivatives as anticancer agents.

As lung cancer was placed foremost part among other types of cancer in terms of mortality. Recent researches are widely focused on developing multi-targeted and site-specific targeted drug designs. In the present study, we designed and developed a series of quinoxaline pharmacophore derivatives as active EGFR inhibitors for the treatment of non-small cell lung cancer. The compounds were synthesized through a condensation reaction between hexane-3,4-dione and methyl 3,4-diaminobenzoate as a first step. Their structures were confirmed by 1 H-NMR, 13 C-NMR, and HRMS spectroscopic methods. Cytotoxicity (MTT) were applied to determine anticancer activity of the compounds against breast (MCF7), fibroblast (NIH3 T3), and lung (A549) cell lines as EGFR inhibitors. Doxorubicin was used as a reference agent, compound 4i exhibited a significant effect among other derivatives with IC50 = 3.902 ± 0.098 μM value against A549 cell line. The docking study showed that the best position on EGFR receptor could be observed with 4i. From the obtained evaluations of the designed series, compound 4i was a promising agent as EGFR inhibitor for further investigation and evaluation studies in the future.

Mutual connected IL-6, EGFR and LIN28/Let7-related mechanisms modulate PD-L1 and IGF upregulation in HNSCC using immunotherapy.

The development of techniques and immunotherapies are widely applied in cancer treatment such as checkpoint inhibitors, adoptive cell therapy, and cancer vaccines apart from radiation therapy, surgery, and chemotherapy give enduring anti-tumor effects. Minority people utilize single-agent immunotherapy, and most people adopt multiple-agent immunotherapy. The difficulties are resolved by including the biomarkers to choose the non-responders' and responders' potentials. The possibility of the potential complications and side effects are examined to improve cancer therapy effects. The Head and Neck Squamous Cell Carcinoma (HNSCC) is analyzed with the help of programmed cell death ligand 1 (PD-L1) and Insulin-like growth factor (IGF). But how IGF and PD-L1 upregulation depends on IL-6, EGFR, and LIN28/Let7-related mechanisms are poorly understood. Briefly, IL-6 stimulates gene expressions of IGF-1/2, and IL-6 cross-activates IGF-1R signaling, NF-κB, and STAT3. NF-κB, up-regulating PD-L1 expressions. IL-6/JAK1 primes PD-L1 for STT3-mediated PD-L1 glycosylation, stabilizes PD-L1 and trafficks it to the cell surface. Moreover, ΔNp63 is predominantly overexpressed over TAp63 in HNSCC, elevates circulating IGF-1 levels by repressing IGFBP3, and activates insulin receptor substrate 1 (IRS1).TP63 and SOX2 form a complex with CCAT1 to promote EGFR expression. EGFR activation through EGF binding extends STAT3 activation, and EGFR and its downstream signaling prolong PD-L1 mRNA half-life. PLC-γ1 binding to a cytoplasmic motif of elevated PD-L1 improves EGF-induced activation of inositol 1,4,5-tri-phosphate (IP3), and diacylglycerol (DAG) subsequently elevates RAC1-GTP. RAC1-GTP was convincingly demonstrated to induce the autocrine production and action of IL-6/IL-6R, forming a feedback loop for IGF and PD-L1 upregulation. Furthermore, the LIN28-Let7 axis mediates the NF-κB-IL-6-STAT3 amplification loop, activated LIN28-Let7 axis up-regulates RAS, AKT, IL-6, IGF-1/2, IGF-1R, Myc, and PD-L1, plays pivotal roles in IGF-1R activation and Myc, NF-κB, STAT3 concomitant activation. Therefore, based on a detailed mechanisms review, our article firstly reveals that IL-6, EGFR, and LIN28/Let7-related mechanisms mediate PD-L1 and IGF upregulation in HNSCC, which comprehensively influences immunity, inflammation, metabolism, and metastasis in the tumor microenvironment, and might be fundamental for overcoming therapy resistance.