EGF-induced Proliferation Research Articles

Virtual screening, molecular dynamics simulations, and in vitro validation of EGFR inhibitors as breast cancer therapeutics

A high abundance of Epidermal Growth Factor Receptor (EGFR) in malignant cells makes them a prospective therapeutic target for basal breast tumors. Although EGFR inhibitors are in development as anticancer therapeutics, there exists limitations due to the dose-limiting cytotoxicity that limits their clinical utilization, thereby necessitating the advancement of effective inhibitors. In the present study, we have developed common pharmacophore hypotheses using 30 known EGFR inhibitors. The best pharmacophore hypothesis DHRRR_1 was utilized for virtual screening (VS) of the Phase database containing 4.3 × 106 fully prepared compounds. The top 1000 hits were further subjected to ADME filtration followed by structure-based VS and Molecular Dynamics (MD) simulation investigations. Based on pharmacophore hypothesis matching, XP glide score, interactions between ligands and active site residues, ADME properties, and MD simulations, the five best hits (SN-01 through SN-05) were preferred for in-vitro cytotoxicity studies. All the molecules except SN-02 exhibited cytotoxicity in Triple Negative Breast Cancer (TNBC) cells. These potential EGFR inhibitors effectively downregulated the EGF-induced proliferation, migration, in-vitro tumorigenic capability, and EGFR activation (pEGFR) in the TNBCs. Additionally, in combination with doxorubicin, the identified EGFR inhibitors significantly decreased the EGF-induced proliferation. SN-04, and SN-05 in the presence of a lower concentration of doxorubicin markedly increased the apoptotic markers expression in the TNBCs, an effect which was comparable to a higher concentration of doxorubicin treatment, alone. These observations suggest that both SN-04 and/or SN-05 can improve the efficacy of chemotherapeutic drug, doxorubicin at a lower concentration to avert the higher dose of chemotherapeutic-induced side effects during breast cancer treatment.

Impact of CD151 overexpression on prognosis and therapy in non-small cell lung cancer patients lacking EGFR mutations.

This study investigates CD151, a protein linked to cancer progression, in non-small cell lung cancer (NSCLC) patients without epidermal growth factor receptor (EGFR) mutations. These patients often have limited treatment options. The study used retrospective analysis to examine 157 adenocarcinoma biopsy specimens and 199 patient cases from The Cancer Genome Atlas, correlating CD151 expression with patient survival. Cellular studies revealed that CD151 interacts with EGFR, influencing epidermal growth factor (EGF)-induced cell proliferation and the effectiveness of the EGFR inhibitor, erlotinib. A strong association was found between CD151 expression and EGFR mutation status. High CD151 expression in the absence of EGFR mutations is correlated with poorer survival outcomes. Biological assays showed that CD151 colocalizes and associates with EGFR, playing a crucial role in regulating EGF-induced cell proliferation via the AKT and ERK1/2 pathways. Importantly, CD151 expression was found to influence the anti-proliferative effects of the EGFR tyrosine kinase inhibitor, erlotinib. High CD151 expression, in the absence of EGFR mutations, was associated with poorer survival outcomes. It could serve as a potential prognostic marker and influence cellular responses to EGFR-targeted treatments. This study highlights CD151 as a potential novel target for therapeutic intervention in NSCLC, especially in populations lacking EGFR mutations.

Inhibition of EGFR attenuates EGF-induced activation of retinal pigment epithelium cell via EGFR/AKT signaling pathway.

To explore the effect of epidermal growth factor receptor (EGFR) inhibition by erlotinib and EGFR siRNA on epidermal growth factor (EGF)-induced activation of retinal pigment epithelium (RPE) cells. Human RPE cell line (ARPE-19 cells) was activated by 100 ng/mL EGF. Erlotinib and EGFR siRNA were used to intervene EGF treatment. Cellular viability, proliferation, and migration were detected by methyl thiazolyl tetrazolium (MTT) assay, bromodeoxyuridine (BrdU) staining assay and wound healing assay, respectively. EGFR/protein kinase B (AKT) pathway proteins and N-cadherin, α-smooth muscle actin (α-SMA), and vimentin were tested by Western blot assay. EGFR was also determined by immunofluorescence staining. EGF treatment for 24h induced a significant increase of ARPE-19 cells' viability, proliferation and migration, phosphorylation of EGFR/AKT proteins, and decreased total EGFR expression. Erlotinib suppressed ARPE-19 cells' viability, proliferation and migration through down regulating total EGFR and AKT protein expressions. Erlotinib also inhibited EGF-induced an increase of proliferative and migrative ability in ARPE-19 cells and clearly suppressed EGF-induced EGFR/AKT proteins phosphorylation and decreased expression of N-cadherin, α-SMA, and vimentin proteins. Similarly, EGFR inhibition by EGFR siRNA significantly affected EGF-induced an increase of cell proliferation, viability, and migration, phosphorylation of EGFR/AKT proteins, and up-regulation of N-cadherin, α-SMA, and vimentin proteins. Erlotinib and EGFR-knockdown suppress EGF-induced cell viability, proliferation, and migration via EGFR/AKT pathway in RPE cells. EGFR inhibition may be a possible therapeutic approach for proliferative vitreoretinopathy (PVR).

Licochalcone D Inhibits Skin Epidermal Cells Transformation through the Regulation of AKT Signaling Pathways.

Cell transformation induced by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) is a critical event in cancer initiation and progression, and understanding the underlying mechanisms is essential for the development of new therapeutic strategies. Licorice extract contains various bioactive compounds, which have been reported to have anticancer and anti-inflammatory effects. This study investigated the cancer preventive efficacy of licochalcone D (LicoD), a chalcone derivative in licorice extract, in EGF and TPA-induced transformed skin keratinocyte cells. LicoD effectively suppressed EGF-induced cell proliferation and anchorage-independent colony growth. EGF and TPA promoted the S phase of cell cycle, while LicoD treatment caused G1 phase arrest and down-regulated cyclin D1 and up-regulated p21 expression associated with the G1 phase. LicoD also induced apoptosis and increased apoptosis-related proteins such as cleaved-caspase-3, cleaved-caspase-7, and Bax (Bcl-2-associated X protein). We further investigated the effect of LicoD on the AKT signaling pathway involved in various cellular processes and found decreased p-AKT, p-GSK3β, and p-NFκB expression. Treatment with MK-2206, an AKT pharmacological inhibitor, suppressed EGF-induced cell proliferation and transformed colony growth. In conclusion, this study demonstrated the potential of LicoD as a preventive agent for skin carcinogenesis.

Promotion of squamous cell carcinoma tumorigenesis by oncogene-mediated THG-1/TSC22D4 phosphorylation.

Carcinoma cells possess high proliferative and invasive potentials and exhibit a resilience against stresses, metabolic disorder, and therapeutic efforts. These properties are mainly acquired by genetic alterations including driver gene mutations. However, the detailed molecular mechanisms have not been fully elucidated. Here, we provide a novel mechanism connecting oncogenic signaling and the tumorigenic properties by a transforming growth factor-β1-stimulated clone 22 (TSC-22) family protein, THG-1 (also called as TSC22D4). THG-1 is localized at the basal layer of normal squamous epithelium and overexpressed in squamous cell carcinomas (SCCs). THG-1 knockdown suppressed SCC cell proliferation, invasiveness, and xenograft tumor formation. In contrast, THG-1 overexpression promoted the EGF-induced proliferation and stratified epithelium formation. Furthermore, THG-1 is phosphorylated by the receptor tyrosine kinase (RTK)-RAS-ERK pathway, which promoted the oncogene-mediated tumorigenesis. Moreover, THG-1 involves in the alternative splicing of CD44 variants, a regulator of invasiveness, stemness, and oxidative stress resistance under the RTK pathway. These findings highlight the pivotal roles of THG-1 as a novel effector of SCC tumorigenesis, and the detection of THG-1 phosphorylation by our established specific antibody could contribute to cancer diagnosis and therapy.

Sustaining the Activation of EGFR Signal by Inflammatory Cytokine IL17A Prompts Cell Proliferation and EGFR-TKI Resistance in Lung Cancer

Non-small-cell lung cancer (NSCLC) is a typical inflammation-associated cancer, and lung adenocarcinoma (LUAD) is the most common pathological subtype. Epidermal growth factor (EGF) receptor (EGFR) mutations are the most common driver mutations of LUAD, and they have been identified as important therapeutic targets by EGFR-tyrosine kinase inhibitors (TKIs). The proinflammatory cytokine, interleukin (IL)-17A, and IL-17A-producing cells were reported to be elevated in the tumor microenvironment and peripheral blood of NSCLC patients and to be correlated with tumor progression and poor prognoses. However, the pathophysiological role of IL-17A in NSCLC remains unclear, although some studies suggested its involvement in cancer cell invasion and metastasis. Herein, we observed that expressions of IL-17A and its receptor, IL-17 receptor C (IL-17RC), were elevated in LUAD tissues and were correlated with poor survival in different lung cancer cohorts. In LUAD cells with mutant EGFR, the IL-17A/IL-17RC axis was shown to enhance phosphorylation of EGFR and Met, thereby promoting proliferation and resistance to EGFR-TKIs such as afatinib. In LUAD cells with wild-type (WT) EGFR, we found that the IL-17A/IL-17RC axis enhanced EGF-induced EGFR activation and cell proliferation through causing impairment of EGF-induced EGFR lysosomal degradation. Collectively, our results indicated diverse impacts of the IL-17A/IL-17RC axis on EGFR activation in LUAD cells with WT and mutant EGFR and suggested that developing therapeutic strategies against IL-17A/IL-17RC would be valuable for LUAD treatment.

Homeobox A7 promotes esophageal squamous cell carcinoma progression through C-C motif chemokine ligand 2-mediated tumor-associated macrophage recruitment.

Homeobox A7 (HOXA7) plays essential roles in multiple malignancies and was reported to be overexpressed in esophageal squamous cell carcinoma (ESCC). However, its functions in the ESCC tumor microenvironment remain to be explored. In this study, we showed that HOXA7 was overexpressed in ESCC among HOXA family members and correlated with tumor-associated macrophage (TAM) infiltration both in The Cancer Genome Atlas database and ESCC clinical samples. Moreover, transactivation of C-C motif chemokine ligand 2 (CCL2) by HOXA7 was identified (real-time quantitative PCR [RT-qPCR], western blot analysis, ELISA, and ChIP-qPCR), which was detected to drive chemotaxis and M2 polarization of macrophages both in vitro (Transwell assay) and in vivo (xenograft tumors models). In addition, CCL2 triggers macrophage expression of epidermal growth factor (EGF) (RT-qPCR and ELISA), which promotes tumor proliferation and metastasis by activating its receptor EGFR. In addition, EGF-induced ESCC cell proliferation and migration can be abrogated by HOXA7 knockdown (CCK-8 proliferation assay, EdU fluorescence, and Transwell assay). These results indicate a novel mechanistic role of HOXA7 in the cross-talk between ESCC and TAMs, which could be an underlying therapeutic target for ESCC.

LY6K depletion modulates TGF-β and EGF signaling.

Lymphocyte antigen 6 complex locus K (LY6K), a glycosylphosphatidylinositol-anchored protein, plays a dynamic role in cancer metastasis. In the current study, we deciphered the effects of LY6K on transforming growth factor-β (TGF-β) and epidermal growth factor (EGF) signaling through clathrin- and caveolin-1 (CAV-1)-mediated endocytosis. Analysis of the TCGA and GTEx dataset were performed to explore the expression and survival of LY6K in cancer patients. Short interfering RNA (siRNA) was used to knockdown the expression of LY6K in human cervical cancer patients. The effect of lack of LY6K on cell proliferation, migration, and invasion was performed, and RT-qPCR and immunoblotting were performed to identify LY6K-affected TGF-β and EGF signaling pathways. Additionally, Immunofluorescence (IF) and transmission electron microscope (TEM) were performed to identify the role of LY6K in CAV-1- and Clathrin-mediated endocytosis. Lymphocyte antigen 6 complex locus K expression level is elevated in higher grade cervical cancer patients correlating with poor overall survival, progression-free survival, and disease-free survival. LY6K-depletion in HeLa and SiHa cancer cells suppressed EGF-induced proliferation and TGF-β-enhanced migration and invasion. Both TGF-β receptor-I (TβRI) and EGF receptor (EGFR) localized at the plasma membrane regardless of LY6K expression, and LY6K bound TβRI irrespective of the presence of TGF-β; however, LY6K did not bind EGFR. LY6K-depleted cells showed impaired Smad2 phosphorylation upon TGF-β treatment and lower proliferation rates following long-term treatment with EGF. We revealed the atypical movement of TβRI and EGFR from plasma membrane upon ligand stimulation in LY6K-depleted cells and an impaired movement of the endocytic proteins clathrin and CAV-1. Our study demonstrates the key role of LY6K in both clathrin- and CAV-1-mediated endocytic pathways regulated by TGF-β and EGF, and it suggests a correlation between LY6K overexpression in cervical cancer cells and poor overall survival.

Abstract LB010: LY6K depletion modulates TGF-β and EGF signaling

Abstract Lymphocyte antigen 6 complex locus K (LY6K), a glycosylphosphatidylinositol-anchored protein, plays a dynamic role in cancer metastasis. In the current study, we deciphered the effects of LY6K on transforming growth factor-β (TGF-β) and epidermal growth factor (EGF) signaling through clathrin- and caveolin-1 (CAV-1)-mediated endocytosis. LY6K expression level is elevated in higher grade cervical cancer patients correlating with poor overall survival, progression-free survival, and disease-free survival. LY6K-depletion in HeLa and SiHa cancer cells suppressed EGF-induced proliferation and TGF-β-enhanced migration and invasion. Both TGF-β receptor-I (TβRI) and EGF receptor (EGFR) localized at the plasma membrane regardless of LY6K expression, and LY6K bound TβRI irrespective of the presence of TGF-β; however, LY6K did not bind EGFR. LY6K-depleted cells showed impaired SMAD2 phosphorylation upon TGF-β treatment and lower proliferation rates following long-term treatment with EGF. We revealed the atypical movement of TβRI and EGFR from plasma membrane upon ligand stimulation in LY6K-depleted cells and an impaired movement of the endocytic proteins clathrin and CAV-1. Subsequently, transmission electron microscopy showed no clathrin and CAV-1-coated vesicles in LY6K-depleted cells. Our study demonstrates the key role of LY6K in both clathrin- and CAV-1-mediated endocytic pathways regulated by TGF-β and EGF, and it suggests a correlation between LY6K overexpression in cervical cancer cells and poor overall survival. Citation Format: Young Yang, Sujeong Park. LY6K depletion modulates TGF-β and EGF signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB010.

FHL2 deficiency impairs follicular development and fertility by attenuating EGF/EGFR/YAP signaling in ovarian granulosa cells

Female subfertility is an increasing reproductive issue worldwide, which is partially related to abnormal ovarian follicular development. Granulosa cells (GCs), by providing the necessary physical support and microenvironment for follicular development, play critical roles in maintaining female fertility. We previously showed that ectopic expression of four and a half LIM domains 2 (FHL2) promoted ovarian granulosa cell tumor progression. However, its function in follicular development and fertility remains unknown. Here, we confirmed that FHL2 is highly expressed in human and mouse ovaries. FHL2 immunosignals were predominantly expressed in ovarian GCs. A Fhl2 knockout (KO) mouse model was generated to examine its roles in follicular development and fertility. Compared with wildtype, knockout of Fhl2 significantly decreased female litter size and offspring number. Furthermore, Fhl2 deficiency reduced ovarian size and impaired follicular development. RNA-sequencing analysis of GCs isolated from either KO or WT mice revealed that, Fhl2 deletion impaired multiple biological functions and signaling pathways, such as Ovarian Putative Early Atresia Granulosa Cell, ErbB, Hippo/YAP, etc. In vitro studies confirmed that FHL2 silencing suppressed GCs growth and EGF-induced GCs proliferation, while its overexpression promoted GC proliferation and decreased apoptosis. Mechanistic studies indicated that FHL2, via forming complexes with transcriptional factors AP-1 or NF-κB, regulated Egf and Egfr expression, respectively. Besides, FHL2 depletion decreased YAP1 expression, especially the active form of YAP1 (nuclear YAP1) in GCs of growing follicles. EGF, serving as an autocrine/paracrine factor, not only induced FHL2 expression and nuclear accumulation, but also stimulated YAP1 expression and activation. Collectively, our study suggests that FHL2 interacts with EGFR and Hippo/YAP signaling to regulate follicular development and maintain fertility. This study illuminates a novel mechanism for follicular development and a potential therapeutic target to address subfertility.

Increased endogenous PKG I activity attenuates EGF-induced proliferation and migration of epithelial ovarian cancer via the MAPK/ERK pathway

The type I cGMP-dependent protein kinase (PKG I) is recognized as a tumor suppressor, but its role in EGFR regulated epithelial ovarian cancer (EOC) progression remains unclear. We evaluated the in vivo and in vitro effects of activated PKG I in EGF-induced EOC cell proliferation, migration, and invasion. The expressions of EGFR and PKG I were elevated, but the activated PKG I was decreased in EOC tissues of patients and cells lines. The addition of 8-Br-cGMP, a specific PKG I activator, attenuated the EGF-induced EOC cell proliferation, migration, and invasion in vitro. Similarly, activated PKG I also attenuated EOC progression in vivo using an EOC xenograft nude mouse model. The activated PKG I interacted with EGFR, causing increased threonine (693) phosphorylation and decreased tyrosine (1068) phosphorylation of EGFR, which resulted in disrupted EGFR-SOS1-Grb2 combination. Subsequently, the cytoplasmic phosphorylation of downstream proteins (c-Raf, MEK1/2, and ERK1/2) were declined, impeding the phosphorylated ERK1/2’s nucleus translocation, and this reduction of phosphorylated tyrosine (1068) EGFR and ERK1/2 were also abolished by Rp-8-Br-cGMPS. Our results suggest that the activation of PKG I attenuates EGF-induced EOC progression, and the 8-Br-cGMP-PKG I-EGFR/MEK/ERK axis might be a potential target for EOC therapy.

A Novel Mechanism Underlying the Inhibitory Effects of Trastuzumab on the Growth of HER2-Positive Breast Cancer Cells.

To improve the efficacy of trastuzumab, it is essential to understand its mechanism of action. One of the significant issues that makes it difficult to determine the precise mechanism of trastuzumab action is the formation of various HER receptor dimers in HER2-positive breast cancer cells. So far, studies have focused on the role of HER2-HER3 heterodimers, and little is known regarding EGFR-HER2 heterodimers. Here, we study the role of trastuzumab on the cell signaling and cell proliferation mediated by EGFR-HER2 heterodimers in BT474 and SRBR3 cells. EGF stimulates the formation of both EGFR homodimer and EGFR-HER2 heterodimer. Trastuzumab only binds to HER2, not EGFR. Therefore, any effects of trastuzumab on EGF-induced activation of EGFR, HER2, and downstream signaling proteins, as well as cell proliferation, are through its effects on EGFR-HER2 heterodimers. We show that trastuzumab inhibits EGF-induced cell proliferation and cell cycle progression in BT474 and SKBR3 cells. Interestingly trastuzumab strongly inhibits EGF-induced Akt phosphorylation and slightly inhibits EGF-induced Erk activation, in both BT474 and SKBR3 cells. These data suggest the presence of a novel mechanism that allows trastuzumab to inhibit EGR-induced Akt activation and cell proliferation, without blocking EGF-induced EGFR-HER2 heterodimerization and activation. We show that trastuzumab inhibits EGF-induced lipid raft localization of the EGFR-HER2 heterodimer. Disruption of the lipid raft with MβCD blocks HER2-mediated AKT activation in a similar way to trastuzumab. MβCD and trastuzumab synergically inhibit AKT activation. We conclude that trastuzumab inhibits EGF-induced lipid raft localization of EGFR-HER2 heterodimer, which leads to the inhibition of Akt phosphorylation and cell proliferation, without blocking the formation and phosphorylation of the EGFR-HER2 heterodimer.

Norcantharidin attenuates epidermal growth factor-induced proliferation, EMT and motility in ARPE-19 cells by modulating the AKT/snail/E-cadherin axis

AimsNorcantharidin (NCTD) is a demethylated derivative of cantharidin demonstrated to have anti-proliferative, anti-inflammatory, and anti-fibrosis properties. The purpose of the current study is to investigate the underlying mechanisms and signaling pathways affected by NCTD in human ARPE-19 cells. Main methodsCell growth and rate of proliferation were assayed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, colony formation assay, and cell cycle distribution/quantification. Cell motility was detected with in vitro migration assay. The level of epithelial-mesenchymal transition (EMT)-related proteins and mRNA (Snail, Slug, E-cadherin) were detected using Western blotting, real-time quantitative polymerase chain reaction, and immunofluorescence assay. Overexpression of Snail plasmid was determined by transfection assay. Key findingsWe found that NCTD reduced epidermal growth factor (EGF)-induced ARPE-19 cell viability and proliferation through increasing the p21 and p27 expression and decreasing the cyclin D1 expression. NCTD also inhibited EGF-mediated EMT and cell motility through increased protein and mRNA levels of E-cadherin and decreased Snail in EGF-induced ARPE-19 cells. Overexpression of Snail significantly decreased ARPE-19 cell motility and increased E-cadherin expression in NCTD-treated cells. Additionally, when NCTD was combined with a PI3K inhibitor (LY294002) significantly decreased the p-AKT and Snail expression, and increased the E-cadherin expression of EGF treatment in ARPE-19 cells. SignificanceThe current findings revealed that NCTD suppresses the EGF-induced proliferation, motility, and EMT of ARPE-19 cells through inactivation of the AKT-mediated Snail/E-cadherin pathway. NCTD may be a potential preventive agent for proliferative vitreoretinopathy.

The ERK5/NF-κB signaling pathway targets endometrial cancer proliferation and survival

Endometrial cancer (EC) is the most common type of gynecologic cancer in women of developed countries. Despite surgery combined with chemo-/radiotherapy regimens, overall survival of patients with high-risk EC tumors is poor, indicating a need for novel therapies. The MEK5-ERK5 pathway is activated in response to growth factors and to different stressors, including oxidative stress and cytokines. Previous evidence supports a role for the MEK5-ERK5 pathway in the pathology of several cancers. We investigated the role of ERK5 in EC. In silico analysis of the PanCancer Atlas dataset showed alterations in components of the MEK5-ERK5 pathway in 48% of EC patients. Here, we show that ERK5 inhibition or silencing decreased EGF-induced EC cell proliferation, and that genetic deletion of MEK5 resulted in EC impaired proliferation and reduced tumor growth capacity in nude mice. Pharmacologic inhibition or ERK5 silencing impaired NF-kB pathway in EC cells and xenografts. Furthermore, we found a positive correlation between ERK5 and p65/RELA protein levels in human EC tumor samples. Mechanistically, genetic or pharmacologic impairment of ERK5 resulted in downregulation of NEMO/IKKγ expression, leading to impaired p65/RELA activity and to apoptosis in EC cells and xenografts, which was rescued by NEMO/IKKγ overexpression. Notably, ERK5 inhibition, MEK5 deletion or NF-kB inhibition sensitized EC cells to standard EC chemotherapy (paclitaxel/carboplatin) toxicity, whereas ERK5 inhibition synergized with paclitaxel to reduce tumor xenograft growth in mice. Together, our results suggest that the ERK5-NEMO-NF-κB pathway mediates EC cell proliferation and survival. We propose the ERK5/NF-κB axis as new target for EC treatment.

Harmine inhibits proliferation and migration of glioblastoma via ERK signalling

Harmine is a beta-carboline alkaloid found in various medicinal plants. While this alkaloid has been used in folk medicine as an anticancer agent, there are no reports of its usage in the treatment of glioblastoma. Therefore, the aim of this study was to investigate the effects of harmine on the proliferation and migration of glioblastoma cells and elucidate the critical signals involved. We found that harmine considerably inhibited the proliferation and migration of glioblastoma cells. Through cell-based real-time FRET imaging, we demonstrated that harmine induces a sustained decrease in ERK signalling, whereas mTOR, Rac1, and JNK remain unaffected. Furthermore, we demonstrated that harmine inhibits EGF-induced ERK signalling and, consequently, EGF-induced cell proliferation and colony formation. Our findings indicate that harmine has anticancer properties in glioblastoma cells. It inhibits cellular proliferation and migration through ERK signalling. These findings suggest that harmine could be a potential therapeutic agent for the treatment of glioblastoma.

Abstract 338: Anti-EGF antibodies significantly improve the activity of BRAF and KRAS inhibitors in preclinical models

Abstract Background: The EGF/EGFR pathway is involved in the emergence of resistance to BRAF and MEK inhibitors and the combination of encorafenib with the anti-EGFR antibody cetuximab has been recently approved in BRAF-positive, advanced colorectal cancer (CRC). Vaccination against EGF represents an alternative to the administration of monoclonal antibodies against EGFR 1-2. In this study, we tested if antibodies generated by vaccination with IN01 (biologic fusion molecule), could improve the antitumor activity of encorafenib and sotorasib in BRAF and KRAS colorectal (CRC) and non-small cell lung cancer (NSCLC) cell lines. Methods: Cell lines with BRAF V600E (HT29, CRC) and KRAS G12C mutations (H2122 and H23, NSCLC) were used. Anti-EGF VacAbs were obtained by immunizing rabbits with recombinant human EGF. Cell lines were treated with encorafenib or sotorasib in combination with anti-EGF VacAbs and the antitumor effects compared to the combination of encorafenib/cetuximab and sotorasib/panitumumab. Cell viability was determined by MTT, changes of total and phosphorylated proteins by Western blotting and emergence of resistance by direct microscopic examination in low density cultures. Results: Anti-EGF VacAbs suppressed the EGF-induced proliferation and blocked the EGFR signaling pathways more efficiently than cetuximab and panitumumab in KRAS and BRAF cell lines. In combination, anti-EGF VacAbs significantly enhanced the antitumor activity of encorafenib (in HT29 cells) and sotorasib (in H2122 and H23 cells), further suppressing EGFR, PRAS40 and ERK 1/2 phosphorylation. Also, the antitumor effects of the anti-EGF VacAbs in combination were superior to those of cetuximab and panitumumab. Finally, the addition of anti-EGF VacAbs to the culture medium significantly delayed the emergence of resistant clones to encorafenib (in HT29) and sotorasib (in H23). Again, the effect was more pronounced than the delay observed when adding cetuximab or panitumumab. Resistant clones generated under all combinations are being analyzed by NGS and Western blotting to determine the possible mechanisms of acquired resistance. Conclusions: Anti-EGF VacAbs potentiate the antitumor effects of encorafenib and sotorasib in cancer cell lines more efficiently than cetuximab and panitumumab. Our data provide a rationale for clinical trials testing the combination of anti-EGF VacAbs with targeted inhibitors in BRAF and KRAS mutant CRC and NSCLC patients. (1)“Anti-Epidermal Growth Factor Vaccine Antibodies Enhance the Efficacy of Tyrosine Kinase Inhibitors and Delay the Emergence of Resistance in EGFR Mutant Lung Cancer Cells” García-Roman S, Molina-Vila MA, et al. J Thorac Oncol. 2018. (2) “Anti-epidermal growth factor vaccine antibodies increase the antitumor activity of kinase inhibitors in ALK and RET rearranged lung cancer cells” García-Roman S, Molina-Vila MA, et al. Transl. Oncol. 2020. Citation Format: Silvia Garcia-Roman, Miguel A. Molina-Vila, Erik d'Hondt, Rafael Rosell. Anti-EGF antibodies significantly improve the activity of BRAF and KRAS inhibitors in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 338.

IQGAP1 is positively correlated with PD-L1 and regulates its expression via mediating STAT proteins phosphorylation

IQ motif containing GTPase activating protein 1 (IQGAP1) is a scaffold protein to transduce multiple signals from the extracellular microenvironment. However, whether IQGAP1 mediates EGF-induced cancer progression has been not observed. In this research, we explored the immunological correlations of IQGAP1. IQGAP1 was up-regulated in most cancer and related to poor prognosis in ovarian cancer. In addition, IQGAP1 was correlated with immune-related genes and tumor-infiltrating lymphocytes. IQGAP1 was a novel EGF-response gene, which was up-regulated by EGF. As the downstream of EGFR, IQGAP1 mediated EGF-induced proliferation, migration and invasion of tumor cells and was essential for EGF-induced PD-L1 expression as well. Mechanically, IQGAP1 interacted with STATs and mediated their phosphorylation. Furthermore, Curcumin inhibited EGFR/IQGAP1 axis to down-regulate PD-L1 and suppress cancer progression. To sum up, IQGAP1 responds to EGF stimulation and mediates EGF-induced phosphorylation of STATs, which is a novel promising target for blocking the EGF-induced cancer progression.

Cell-penetrating peptides containing the progesterone receptor polyproline domain inhibits EGF signaling and cell proliferation in lung cancer cells.

Non-small cell lung cancer (NSCLC) accounts for the majority (80–85%) of all lung cancers. All current available treatments have limited efficacy. The epidermal growth factor receptor (EGFR) plays a critical role in the development and progression of NSCLC, with high EGFR expression associated with increased cell proliferation and poor prognosis. Thus, interfering with EGFR signaling has been shown to effectively reduce cell proliferation and help in the treatment of NSCLC. We previously demonstrated that the progesterone receptor (PR) contains a polyproline domain (PPD) that directly interacts with Src homology 3 (SH3) domain-containing molecules and expression of PR-PPD peptides inhibits NSCLC cell proliferation. In this study, we investigated whether the introduction of PR-PPD by cell-penetrating peptides (CPPs) could inhibit EGF-induced cell proliferation in NSCLC cells. PR-PPD was attached to a cancer-specific CPP, Buforin2 (BR2), to help deliver the PR-PPD into NSCLC cells. Interestingly, addition of BR2-2xPPD peptides containing two PR-PPD repeats was more effective in inhibiting NSCLC proliferation and significantly reduced EGF-induced phosphorylation of Erk1/2. BR2-2xPPD treatment induced cell cycle arrest by inhibiting the expression of cyclin D1 and CDK2 genes in EGFR-wild type A549 cells. Furthermore, the combination treatment of EGFR-tyrosine kinase inhibitors (TKIs), including Gefitinib or Erlotinib, with BR2-2xPPD peptides further suppressed the growth of NSCLC PC9 cells harboring EGFR mutations as compared to EGFR-TKIs treatment alone. Importantly, BR2-2xPPD peptides mediated growth inhibition in acquired Gefitinib- and Erlotinib- resistant lung adenocarcinoma cells. Our data suggests that PR-PPD is the minimal protein domain sufficient to inhibit NSCLC cell growth and has the potential to be developed as a novel NSCLC therapeutic agent.

Propofol Affects EGF's Activity in Intestinal Cell by Down-Regulating EGFR-Mediated Intracellular Signaling.

Propofol is a commonly used anesthetic drug in clinic. In recent years, a series of non-anesthetic effects of propofol have been discovered. Studies have shown that propofol has many effects on the intestine. Epidermal growth factor (EGF) is one of the most important growth factors that could regulate intestinal growth and development. In the current study, we studied the effect of protocol on the biological activity of EGF on intestinal tissue and cell models. Through flow cytometry, indirect immunofluorescence and Western-blot and other technologies, it was found that propofol reduced the activity of EGF on intestinal cells, which inhibited EGF-induced intestinal cell proliferation and changed the cell behavior of EGF. To further explore the potential mechanism by which propofol down-regulated epidermal growth factor receptor (EGFR)-induced signaling, we carried out a series of related experiments, and found that propofol may inhibit the proliferation of intestinal cells by inhibiting the EGFR-mediated intracellular signaling pathway. The current research will lay the theoretical and experimental basis for further study of the effect of propofol on the intestine.

An Approach for Recombinant Epidermal Growth Factor Purification Using an Elastin-Like Protein Tag

Introduction: Wide applications in research, clinical and cosmetic industry of human epidermal growth factor (hEGF) made it a research interest target. Its production in different expression systems has shown several limitations. Recombinant expression of hEGF in E. coli is always accompanied by inclusion body formation. The object of this study is to the evaluation of a chromatography-independent approach for the production of EGF in E. coli as soluble form. Materials and Methods: In order to evaluate a chromatogram independent purification approach for recombinant hEGF production in a soluble form, the hEGF gene was fused to an elastin-like protein (ELP) and expressed in E. coli BL21 (DE3) using pET26b expression vector for secretion the product into periplasmic space. Results: Periplasmic protein content analysis confirmed that the recombinant protein is secreted into the periplasm. The purification process was done by using 0.4 M ammonium sulfate in two cycles of inverse phase transition (ITC). After two cycles of purification, purity reached more than 95%. Western blotting analysis with the monoclonal anti-EGF antibody has confirmed the accuracy of EGF. Biological activity of the purified protein was investigated on NIH-3T3 cell line and results indicated EGF-induced proliferation in treated cells. Our results showed periplasmic expression is the proper approach to the production of soluble recombinant hEGF. By using ELP fused to EGF, the purification process was established without applying chromatography which will result in decreasing in final costs. Conclusions: This study introduced a new economic and efficient approach to the production and purification of recombinant hEGF.