Unraveling the ecological landscape of mast cells in esophageal cancer through single-cell RNA sequencing.

Background: Esophageal cancer (EC) is a major health issue, ranking seventh in incidence and sixth in mortality worldwide. Despite advancements in multidisciplinary treatment approaches, the 5-year survival rate for EC remains low at 21%. Challenges in EC treatment arise from late-stage diagnosis, high malignancy, and poor prognosis. Understanding the tumor microenvironment is critical, as it includes various cellular and extracellular components that influence tumor behavior and treatment response. Mast cells (MCs), as tissue-resident immune cells, play dual roles in tumor dynamics. High-throughput single-cell RNA sequencing offers a powerful tool for analyzing tumor heterogeneity and immune interactions, although its application in EC is limited. Methods: In this study, we investigated the immune microenvironment of EC using single-cell RNA sequencing and established a comprehensive immune profile. We also performed analysis of upstream transcription factors and downstream pathway enrichment to further comprehensively decipher MCs in EC. Besides, we performed knockdown experiments to explore the role of epidermal growth factor receptor (EGFR) signaling pathway in MCs-tumor cell interactions, highlighting its potential as a prognostic marker. Finally, we constructed a prognostic model for EC, which provided valuable suggestions for the diagnosis and prognosis of EC. Results: Our analysis identified 11 major cell types, of which MCs were particularly present in pericarcinoma tissues. Further grouping of the 5,001 MCs identified 8 distinct subtypes, including SRSF7-highly expressed MCs, which showed strong tumor preference and potential tumor-promoting properties. Moreover, we identified the key signaling receptor EGFR and validated it by in vitro knockdown experiments, demonstrating its cancer-promoting effects. In addition, we established an independent prognostic indicator, SRSF7+ MCs risk score (SMRS), which showed a correlation between high SMRS group and poor prognosis. Conclusion: These findings illuminate the complex interactions within the tumor microenvironment of EC and suggest that targeting specific MCs subtypes, particularly via the EGFR signaling pathway, may present novel therapeutic strategies. This study establishes a comprehensive immune map of EC, offering insights for improved treatment approaches.

EGFR-dependent actomyosin patterning coordinates morphogenetic movements between tissues in Drosophila melanogaster.

The movements that give rise to the body's structure are powered by cell shape changes and rearrangements that are coordinated at supracellular scales. How such cellular coordination arises and integrates different morphogenetic programs is unclear. Using quantitative imaging, we found a complex pattern of adherens junction (AJ) levels in the ectoderm prior to gastrulation onset in Drosophila. AJ intensity exhibited a double-sided gradient, with peaks at the dorsal midline and ventral neuroectoderm. We show that this dorsal-ventral AJ pattern is regulated by epidermal growth factor (EGF) signaling and that this signal is required for ectoderm cell movement during mesoderm invagination and axis extension. We identify AJ levels and junctional actomyosin as downstream effectors of EGFR signaling. Overall, our study demonstrates an EGF-patterned mechanical feedback mechanism that coordinates tissue folding and convergent extension to facilitate embryo-wide gastrulation movements.

Pik3c3 expression profiling in the mouse kidney and its role in proximal tubule cell physiology.

The class 3 phosphatidylinositol 3-kinase (Pik3c3) plays critical roles in regulating autophagy, endocytosis, and nutrient sensing, but its expression profile in the kidney remains undefined. Recently, we validated a Pik3c3 antibody through immunofluorescence staining of kidney tissues from cell type-specific Pik3c3 knockout mice. Immunohistochemistry unveiled significant disparities in Pik3c3 expression levels across various kidney cell types. Notably, renal interstitial cells exhibit minimal Pik3c3 expression. Further, coimmunofluorescence staining, utilizing nephron segment- or cell type-specific markers, revealed nearly undetectable levels of Pik3c3 expression in glomerular mesangial cells and endothelial cells. Intriguingly, although podocytes exhibit the highest Pik3c3 expression levels among all kidney cell types, the renal proximal tubule cells (RPTCs) express the highest level of Pik3c3 among all renal tubules. RPTCs are known to express the highest level of the epidermal growth factor receptor (EGFR) in adult kidneys; however, the role of Pik3c3 in EGFR signaling within RPTCs remains unexplored. Therefore, we conducted additional cell culture studies. The results demonstrated that Pik3c3 inhibition significantly delayed EGF-stimulated EGFR degradation and the termination of EGFR signaling in RPTCs. Mechanistically, Pik3c3 inhibition surprisingly did not affect the initial endocytosis process but instead impeded the lysosomal degradation of EGFR. In summary, this study defines, for the first time, the expression profile of Pik3c3 in the mouse kidney and also highlights a pivotal role of Pik3c3 in the proximal tubule cells. These findings shed light on the intricate mechanisms underlying Pik3c3-mediated regulation of EGFR signaling, providing valuable insights into the role of Pik3c3 in renal cell physiology. NEW & NOTEWORTHY This is the first report defining the class 3 phosphatidylinositol 3-kinase (Pik3c3) expression profile in the kidney. Pik3c3 is nearly absent in renal interstitial cells, glomerular mesangial cells, and endothelial cells. Remarkably, glomerular podocytes express the highest Pik3c3 level in the kidney. However, the proximal tubule exhibits the highest expression level among all renal tubules. This study also unveils the pivotal role of Pik3c3 in regulating EGFR degradation and signaling termination in RPTCs, furthering our understanding of Pik3c3 in renal cell physiology.

Solanine Inhibits Proliferation and Angiogenesis and Induces Apoptosis through Modulation of EGFR Signaling in KB-ChR-8-5 Multidrug-Resistant Oral Cancer Cells.

Background: The most important factors contributing to multi-drug resistance in oral cancer include overexpression of the EGFR protein and the downstream malignancy regulators that are associated with it. This study investigates the impact of solanine on inflammation, proliferation, and angiogenesis inhibition in multidrug-resistant oral cancer KB-Chr-8-5 cells through inhibition of the EGFR/PI3K/Akt/NF-κB signaling pathway. Methods: Cell viability was assessed using an MTT assay to evaluate cytotoxic effects. Production of reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨM), and AO/EtBr staining were analyzed to assess apoptosis and mitochondrial dysfunction. Western blotting was employed to examine protein expression related to angiogenesis, apoptosis, and signaling pathways. Experiments were conducted in triplicate. Results: Solanine treatment at concentrations of 10, 20, and 30 µM significantly increased ROS production, which is indicative of its antioxidant properties. This increase was associated with decreased mitochondrial membrane potential (ΔΨM) with p < 0.05, suggesting mitochondrial dysfunction. Inhibition of EGFR led to reduced activity of PI3K, Akt, and NF-κB, resulting in decreased expression of iNOS, IL-6, Cyclin D1, PCNA, VEGF, Mcl-1, and HIF-1α and increased levels of the apoptotic proteins Bax, caspase-9, and caspase-3. These changes collectively inhibited the growth of multidrug-resistant (MDR) cancer cells. Conclusions: Solanine acts as a potent disruptor of cellular processes by inhibiting the EGFR-mediated PI3K/Akt/NF-κB signaling pathway. These results suggest that solanine holds promise as a potential preventive or therapeutic agent against multidrug-resistant cancers.

miR-107 reverses the multidrug resistance of gastric cancer by targeting the CGA/EGFR/GATA2 positive feedback circuit.

Chemotherapy is still the main therapeutic strategy for gastric cancer (GC). However, most patients eventually acquire multidrug resistance (MDR). Hyperactivation of the EGFR signaling pathway contributes to MDR by promoting cancer cell proliferation and inhibiting apoptosis. We previously identified the secreted protein CGA as a novel ligand of EGFR and revealed a CGA/EGFR/GATA2 positive feedback circuit that confers MDR in GC. Herein, we outline a microRNA-based treatment approach for MDR reversal that targets both CGA and GATA2. We observed increased expression of CGA and GATA2 and increased activation of EGFR in GC samples. Bioinformatic analysis revealed that miR-107 could simultaneously target CGA and GATA2, and the low expression of miR-107 was correlated with poor prognosis in GC patients. The direct interactions between miR-107 and CGA or GATA2 were validated by luciferase reporter assays and Western blot analysis. Overexpression of miR-107 in MDR GC cells increased their susceptibility to chemotherapeutic agents, including fluorouracil, adriamycin, and vincristine, in vitro. Notably, intratumor injection of the miR-107 prodrug enhanced MDR xenograft sensitivity to chemotherapies in vivo. Molecularly, targeting CGA and GATA2 with miR-107 inhibited EGFR downstream signaling, as evidenced by the reduced phosphorylation of ERK and AKT. These results suggest that miR-107 may contribute to the development of a promising therapeutic approach for the treatment of MDR in GC.

Timosaponin Aâ ¢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway.

The current study aimed to assess the effect of timosaponin AⅢ (T-AⅢ) on drug-metabolizing enzymes during anticancer therapy. The in vivo experiments were conducted on nude and ICR mice. Following a 24-day administration of T-AⅢ, the nude mice exhibited an induction of CYP2B10, MDR1, and CYP3A11 expression in the liver tissues. In the ICR mice, the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration. The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6, MDR1, and CYP3A4, along with constitutive androstane receptor (CAR) activation. Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression. Furthermore, other CAR target genes also showed a significant increase in the expression. The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice. Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation, with this effect being partially reversed by the ERK activator t-BHQ. Inhibition of the ERK1/2 signaling pathway was also observed in vivo. Additionally, T-AⅢinhibited the phosphorylation of EGFR at Tyr1173 and Tyr845, and suppressed EGF-induced phosphorylation of EGFR, ERK, and CAR. In the nude mice, T-AⅢ also inhibited EGFR phosphorylation. These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.

RGC32 promotes the progression of ccRCC by activating the NF-κB/SHP2/EGFR signaling pathway.

BACKGROUND: The role and clinical significance of the response gene to complement 32 (RGC32) in various cancers have been documented, yet its implications in clear cell Renal Cell Carcinoma (ccRCC) remain underexplored. METHODS: This study investigated RGC32's diagnostic and prognostic relevance in ccRCC using bioinformatics methods with data from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). The impact of RGC32 on ccRCC progression was assessed through nude mouse tumor assays. Immunohistochemistry evaluated RGC32 levels in ccRCC and adjacent normal tissues, while cell proliferation, migration, and invasion capabilities were analyzed using CCK-8, monoclonal proliferation assays, Transwell, and wound healing assays, respectively. Western blotting measured relevant protein expressions. RESULTS: Bioinformatics analysis highlighted RGC32's significant role in ccRCC pathogenesis. Elevated RGC32 expression in ccRCC tissues was linked to disease progression. Functionally, RGC32 was found to enhance the expression of proteins such as p-PI3K, CyclinA1, CyclinD1, p-STAT3, MMP2, MMP3, MMP9, p-SMAD2/3, Snail, Slug, and N-Cadherin via the NF-κB/SHP2/EGFR pathway, while decreasing E-cadherin levels. Moreover, RGC32 facilitated ccRCC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT). CONCLUSION: RGC32 is a pivotal factor in ccRCC development, primarily through the activation of the NF-κB/SHP2/EGFR signaling pathway.

The Treatment of Tubal Inflammatory Infertility using Yinjia Tablets through EGFR/MEK/ERK Signaling Pathway based on Network Pharmacology.

Background: Salpingitis obstructive infertility (SOI) refers to infertility caused by abnormal conditions such as tubal adhesion and blockage caused by acute and chronic salpingitis. SOI has a serious impact on women's physical and mental health and family harmony, and it is a clinical problem that needs to be solved urgently.

Objective: The purpose of the present study was to explore the potential pharmacological mechanisms of the Yinjia tablets (Yin Jia Pian, YJP) on tubal inflammation.

Methods: Networks of YJP-associated targets and tubal inflammation-related genes were constructed through the STRING database. Potential targets and pathway enrichment analysis related to the therapeutic efficacy of YJP were identified using Cytoscape and Database for Annotation, Visualization, and Integrated Discovery (metascape). E. coli was used to establish a rat model of tubal inflammation and to validate the predictions of network pharmacology and the therapeutic efficacy of YJP. H&E staining was used to observe the pathological changes in fallopian tubes. TEM observation of the ultrastructure of the fallopian tubes. ELISA was used to detect the changes of IL-6 and TNF-α in fallopian tubes. Immunohistochemistry was used to detect the expression of ESR1. The changes of Bcl-2, ERK1/2, p-ERK1/2, MEK, p-MEK, EGFR, and p-EGFR were detected by western blot.

Results: Through database analysis, it was found that YJP shared 105 identical targets with the disease. Network pharmacology analysis showed that IL-6, TNF, and EGFR belong to the top 5 core proteins associated with salpingitis, and EGFR/MEK/ERK may be the main pathway involved. The E. coli-induced disease rat model of fallopian tube tissue showed damage, mitochondrial disruption, and increased levels of the inflammatory factors IL-6 and TNF-α. Tubal inflammatory infertility rats have increased expression of Bcl-2, p-ERK1/2, p-MEK, and p-EGFR, and decreased expression of ESR1. In vivo, experiments showed that YJP improved damage of tissue, inhibited shedding of tubal cilia, and suppressed the inflammatory response of the body. Furthermore, YJP inhibited EGFR/MEK/ERK signaling, inhibited the apoptotic protein Bcl-2, and upregulated ESR1.

Conclusion: This study revealed that YJP Reducing tubal inflammation and promoting tissue repair may be associated with inhibition of the EGFR/MEK/ERK signaling pathway.

EGFR Inhibition by Erlotinib Rescues Desmosome Ultrastructure and Keratin Anchorage and Protects against Pemphigus Vulgaris IgG-Induced Acantholysis in Human Epidermis.

Pemphigus is a severe blistering disease caused by autoantibodies primarily against the desmosomal cadherins desmoglein (DSG)1 and DSG3, which impair desmosome integrity. Especially for the acute phase, additional treatment options allowing to reduce corticosteroids would fulfill an unmet medical need. In this study, we provide evidence that EGFR inhibition by erlotinib ameliorates pemphigus vulgaris IgG-induced acantholysis in intact human epidermis. Pemphigus vulgaris IgG caused phosphorylation of EGFR (Y845) and Rous sarcoma-related kinase in human epidermis. In line with this, a phosphotyrosine kinome analysis revealed a robust response associated with EGFR and Rous sarcoma-related kinase family kinase signaling in response to pemphigus vulgaris IgG but not to pemphigus foliaceus autoantibodies. Erlotinib inhibited pemphigus vulgaris IgG-induced epidermal blistering and EGFR phosphorylation, loss of desmosomes, as well as ultrastructural alterations of desmosome size, plaque symmetry, and keratin filament insertion and restored the desmosome midline considered as hallmark of mature desmosomes. Erlotinib enhanced both single-molecule DSG3-binding frequency and strength and delayed DSG3 fluorescence recovery, supporting that EGFR inhibition increases DSG3 availability and cytoskeletal anchorage. Our data indicate that EGFR is a promising target for pemphigus therapy owing to its link to several signaling pathways known to be involved in pemphigus pathogenesis.

EGFR signaling controls directionality of epithelial multilayer formation upon loss of cell polarity.

Apical-basal polarity is maintained by distinct protein complexes that reside in membrane junctions, and polarity loss in monolayered epithelial cells can lead to formation of multilayers, cell extrusion, and/or malignant overgrowth. Yet, how polarity loss cooperates with intrinsic signals to control directional invasion toward neighboring epithelial cells remains elusive. Using the Drosophila ovarian follicular epithelium as a model, we found that posterior follicle cells with loss of lethal giant larvae (lgl) or Discs large (Dlg) accumulate apically toward germline cells, whereas cells with loss of Bazooka (Baz) or atypical protein kinase C (aPKC) expand toward the basal side of wildtype neighbors. Further studies revealed that these distinct multilayering patterns in the follicular epithelium were determined by epidermal growth factor receptor (EGFR) signaling and its downstream target Pointed, a zinc-finger transcription factor. Additionally, we identified Rho kinase as a Pointed target that regulates formation of distinct multilayering patterns. These findings provide insight into how cell polarity genes and receptor tyrosine kinase signaling interact to govern epithelial cell organization and directional growth that contribute to epithelial tumor formation.

Secretory phospholipase (sPLA2-IIA) regulates breast cancer stem cells differentiation and metastatic potential.

Breast cancer is the second most cancer worldwide in females. The primary factor responsible for tumor recurrence is the presence of breast cancer stem cells (BCSCs), which escape the chemo-radiotherapy. In this study, we have investigated the role of Secretory phospholipase-A2 Group 2A (sPLA2-IIA) that is overexpressed in BCSCs of MCF7 and MDA-MB-231 breast cancer cell lines. Further, overexpression of sPLA2-IIA revealed an increased EGFR/JNK/c-JUN/c-FOS signaling in BCSCs, while sPLA2-IIA knockdown significantly reduced the percentage of BCSCs and decreased signaling in both the cell lines. Importantly, sPLA2-IIA knockdown showed differentiation of BCSCs. Strikingly, PET imaging showed a decreased metastatic potential of BCSCs. Our study revealed a novel role of sPLA2-IIA in regulating BCSCs, which play a crucial role in regulating the differentiation and metastatic potential of BCSCs.

Resistance to hormone therapy in breast cancer cells promotes autophagy and EGFR signaling pathway.

Breast cancer is the leading cause of cancer deaths for women worldwide. Endocrine therapies represent the cornerstone for hormone-dependent breast cancer treatment. However, in many cases, endocrine resistance is induced with poor prognosis for patients. In the current study, we have developed MCF-7 cell lines resistant to fulvestrant (MCF-7Fulv) and tamoxifen (MCF-7Tam) aiming at investigating mechanisms underlying resistance. Both resistant cell lines exerted lower proliferation capacity in two-dimensional (2-D) cultures but retain estrogen receptor α (ERα) expression and proliferate independent of the presence of estrogens. The established cell lines tend to be more aggressive exhibiting advanced capacity to form colonies, increased expression of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and heterodimerization of ERBB family receptors and activation of EGFR downstream pathways like MEK/ERK1/2 and PI3K/AKT. Tyrosine kinase inhibitors tested against resistant MCF-7Fulv and MCF-7Tam cells showed moderate efficacy to inhibit cell proliferation, except for lapatinib, which concomitantly inhibits both EGFR and HER2 receptors and strongly reduced cell proliferation. Furthermore, increased autophagy was observed in resistant MCF-7Fulv and MCF-7Tam cells as shown by the presence of autophagosomes and increased Beclin-1 levels. The increased autophagy in resistant cells is not associated with increased apoptosis, suggesting a cytoprotective role for autophagy that may favor cells' survival and aggressiveness. Thus, by exploiting those underlying mechanisms, new targets could be established to overcome endocrine resistance.NEW & NOTEWORTHY The development of resistance to hormone therapy caused by both fulvestrant and tamoxifen promotes autophagy with concomitant apoptosis evasion, rendering cells capable of surviving and growing. The fact that resistance also triggers ERBB family signaling pathways, which are poorly inhibited by tyrosine kinase inhibitors might attribute to cells' aggressiveness. It is obvious that the development of endocrine therapy resistance involves a complex interplay between deregulated ERBB signaling and autophagy that may be considered in clinical practice.

Activation of the EGFR/PI3K/AKT pathway limits the efficacy of trametinib treatment in head and neck cancer.

Blocking the mitogen-activated protein kinase (MAPK) pathway with the MEK1/2 inhibitor trametinib has produced promising results in patients with head and neck squamous cell carcinoma (HNSCC). In the current study, we showed that trametinib treatment leads to overexpression and activation of the epidermal growth factor receptor (EGFR) in HNSCC cell lines and patient-derived xenografts. Knockdown of EGFR improved trametinib treatment efficacy both in vitro and in vivo. Mechanistically, we demonstrated that trametinib-induced EGFR overexpression hyperactivates the phosphatidylinositol 3-kinase (PI3K)/AKT pathway. In vitro, blocking the PI3K pathway with GDC-0941 (pictilisib), or BYL719 (alpelisib), prevented AKT pathway hyperactivation and enhanced the efficacy of trametinib in a synergistic manner. In vivo, a combination of trametinib and BYL719 showed superior antitumor efficacy vs. the single agents, leading to tumor growth arrest. We confirmed our findings in a syngeneic murine head and neck cancer cell line in vitro and in vivo. Taken together, our findings show that trametinib treatment induces hyperactivation of EGFR/PI3K/AKT; thus, blocking of the EGFR/PI3K pathway is required to improve trametinib efficacy in HNSCC.

Tubular cell transcriptional intermediary factor 1γ deficiency exacerbates kidney injury-induced tubular cell polyploidy and fibrosis.

Tubulointerstitial fibrosis is considered the final convergent pathway of progressive chronic kidney diseases (CKD) regardless of etiology. However, mechanisms underlying kidney injury-induced fibrosis largely remain unknown. Recent studies have indicated that transcriptional intermediary factor 1γ (TIF1γ) inhibits the progression of fibrosis in other organs. Here, we found that TIF1γ was highly expressed in the cytoplasm and nucleus of the kidney proximal tubule. Interestingly, we found tubular TIF1γ expression was decreased in patients with CKD, including those with diabetes, hypertension, and IgA nephropathy, and in mouse models with experimental kidney fibrosis (unilateral ureteral obstruction [UUO], folic acid nephropathy [FAN], and aristolochic acid-induced nephrotoxicity). Tubule-specific knock out of TIF1γ in mice exacerbated UUO- and FAN-induced tubular cell polyploidy and subsequent fibrosis, whereas overexpression of kidney TIF1γ protected mice against kidney fibrosis. Mechanistically, in tubular epithelial cells, TIF1γ exerted an antifibrotic role via transforming growth factor-ß (TGF-ß)-dependent and -independent signaling. TIF1γ hindered TGF-ß signaling directly by inhibiting the formation and activity of the transcription factor Smad complex in tubular cells, and we discovered that TIF1γ suppressed epidermal growth factor receptor (EGFR) signaling upstream of TGF-ß signaling in tubular cells by ubiquitylating EGFR at its lysine 851/905 sites thereby promoting EGFR internalization and lysosomal degradation. Pharmacological inhibition of EGFR signaling attenuated exacerbated polyploidization and the fibrotic phenotype in mice with tubule deletion of TIF1γ. Thus, tubular TIF1γ plays an important role in kidney fibrosis by suppressing profibrotic EGFR and TGF-ß signaling. Hence, our findings suggest that maintaining homeostasis of tubular TIF1γ may be a new therapeutic option for treating tubulointerstitial fibrosis and subsequent CKD.

Selenium modulates AR/IGF-1R/EGFR and TROP2 signaling pathways and improves anticancer efficacy in murine mammary carcinoma 4T1.

The micronutrient selenium (Se) has been shown to exert potential anticancer properties. This study aimed to evaluate the effects of Se (in Se yeast form) on the selenoproteins (SELENO), AR/IGF-1R/EGFR, PI3K/Akt/mTOR and Ras/Raf/ERK cascades, and immune checkpoint blockade in TNBC murine 4T1 cells. We also assessed the effects of combination treatment with chemotherapeutic doxorubicin and Se on trophoblast cell surface antigen 2 (TROP2) levels. Compared with the control groups, cells incubated with Se (0.25, 0.5, 0.75, 1.0, 1.5 µg Se/mL) have lower viability, raised intracellular Se concentrations and SELENO expression, and higher malondialdehyde products in a dose-dependent manner. Se induced the inactivation of AR/IGF-1R/EGFR and downregulation of the PI3K/Akt/mTOR and Ras/Raf/ERK signaling molecules. Se-treated cells also exhibited decreased mitochondrial membrane potential, reduced levels of the cell cycle regulatory protein cyclin D1, cancer stemness, metastatic and EMT-related markers, and increased apoptosis. Subsequently, Se treatment significantly suppressed PD-1/PD-L1 and CTLA-4 mRNA levels and proteins. Doxorubicin decreased 4T1 cell viability and TROP2 expression levels, but the addition of Se to doxorubicin contributed to further reductions. Similar responses to Se treatment were also observed in the human MDA-MB-231 and MCF-7 breast cancer cells. These results show that Se upregulates SELENO and anti-AR/IGF-1R/EGFR signaling in TNBC cells, thus inducing oxidative stress-dependent apoptosis and cell cycle arrest, stemness, EMT, and metastasis, as well as blocking the immune checkpoint molecules. TROP2 down-regulation with Se is also a potential anti-TNBC therapeutic target.

Cadmium promotes colorectal cancer metastasis through EGFR/Akt/mTOR signaling cascade and dynamics.

Cadmium (Cd) is a hazardous environmental heavy metal with a prolonged biological half-life. Due to the main route of foodborne exposure, the intestinal tract is particularly vulnerable to Cd-induced toxicity. However, the chronic toxicity and underlying mechanisms of Cd in intestinal diseases, including colorectal cancer (CRC), still remain vague. Herein, we aim to investigate the long-term effects of Cd exposure on CRC development and the key signaling event. Our findings indicate that chronic and low-dose exposure to Cd promoted the invasion and metastasis capability of CRC cells in vitro and in mice, with a marginal increase in cell growth. The expression of cell junction-related genes was down-regulated while those molecules that facilitate cell mobility were significantly increased by Cd exposure. Epidermal growth factor receptor (EGFR) signaling was identified to play the dominant role in Cd-promoted CRC metastasis. Interestingly, Cd activated EGFR in a non-canonical manner that exhibited distinct signaling dynamics from the canonical ligand. In contrast to EGF, which induced transient EGFR signaling and ERK activation, Cd promoted sustained EGFR signaling to trigger Akt/mTOR cascade. The unique signaling dynamics of EGFR induced by Cd provoked responses that preferably enhanced the metastatic capacity rather than the growth. Furthermore, blockade of EGFR abrogated the promoting effects of Cd on the liver metastasis of CRC cells. In conclusion, this study provides a better understanding of the long-term influences of environmental Cd on CRC metastasis and reveals the unique EGFR signaling dynamics induced by Cd exposure.

MFN2 suppresses clear cell renal cell carcinoma progression by modulating mitochondria-dependent dephosphorylation of EGFR.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most lethal renal cancer. An overwhelming increase of patients experience tumor progression and unfavorable prognosis. However, the molecular events underlying ccRCC tumorigenesis and metastasis remain unclear. Therefore, uncovering the underlying mechanisms will pave the way for developing novel therapeutic targets for ccRCC. In this study, we sought to investigate the role of mitofusin-2 (MFN2) in supressing ccRCC tumorigenesis and metastasis. METHODS: The expression pattern and clinical significance of MFN2 in ccRCC were analyzed by using the Cancer Genome Atlas datasets and samples from our independent ccRCC cohort. Both in vitro and in vivo experiments, including cell proliferation, xenograft mouse models and transgenic mouse model, were used to determine the role of MFN2 in regulating the malignant behaviors of ccRCC. RNA-sequencing, mass spectrum analysis, co-immunoprecipitation, bio-layer interferometry and immunofluorescence were employed to elucidate the molecular mechanisms for the tumor-supressing role of MFN2. RESULTS: we reported a tumor-suppressing pathway in ccRCC, characterized by mitochondria-dependent inactivation of epidermal growth factor receptor (EGFR) signaling. This process was mediated by the outer mitochondrial membrane (OMM) protein MFN2. MFN2 was down-regulated in ccRCC and associated with favorable prognosis of ccRCC patients. in vivo and in vitro assays demonstrated that MFN2 inhibited ccRCC tumor growth and metastasis by suppressing the EGFR signaling pathway. In a kidney-specific knockout mouse model, loss of MFN2 led to EGFR pathway activation and malignant lesions in kidney. Mechanistically, MFN2 preferably binded small GTPase Rab21 in its GTP-loading form, which was colocalized with endocytosed EGFR in ccRCC cells. Through this EGFR-Rab21-MFN2 interaction, endocytosed EGFR was docked to mitochondria and subsequently dephosphorylated by the OMM-residing tyrosine-protein phosphatase receptor type J (PTPRJ). CONCLUSIONS: Our findings uncover an important non-canonical mitochondria-dependent pathway regulating EGFR signaling by the Rab21-MFN2-PTPRJ axis, which contributes to the development of novel therapeutic strategies for ccRCC.

EGF-receptor phosphorylation and downstream signaling are activated by genistein during subacute liver damage.

The epidermal growth factor receptor (EGFR) plays an important role on hepatic protection in acute and chronic liver injury. The aim of this study was to investigate the role of genistein on EGFR expression, phosphorylation and signaling pathways in experimental subacute liver damage induced by carbon tetrachloride (CCl4). We used male Wistar rats that were randomly divided into four groups: (1) Control; (2) Genistein 5 mg/kg per oral; (3) Subacute liver damage induced by CCl4 4 mg/kg subcutaneously; and (4) Animals received CCl4 and genistein at the dosage indicated. The effect of genistein on EGFR expression, phosphorylation and signaling pathways were investigated by western blot and densitometric analyses. Histological changes were evaluated on slices stained with Hematoxylin-Eosin and Masson´s trichromic, as well as an immunohistochemical analysis for proliferating cell nuclear antigen (PCNA). Additionally, pro-inflammatory cytokines and liver enzymes were quantified. Our study showed that genistein increased EGFR expression, EGFR-specific tyrosine residues phosphorylation (pY1068-EGFR and pY84-EGFR), signal transducer and activator of transcription phosphorylation (pSTAT5), protein kinase B phosphorylation (pAKT) and PCNA in animals with CCl4-induced subacute liver damage. It was found a significant reduction of pro-inflammatory cytokines in serum from animals with subacute liver damage treated with genistein. Those effects were reflected in an improvement in the architecture and liver function. In conclusion, genistein can induce a transactivation of EGFR leading to downstream cell signaling pathways as early events associated with regeneration and hepatoprotection following subacute liver damage.

Diarylheptanoid 35d overcomes EGFR TKI resistance by inducing hsp70-mediated lysosomal degradation of EGFR in EGFR-mutant lung adenocarcinoma.

Epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LUAD) patients often respond to EGFR tyrosine kinase inhibitors (TKIs) initially but eventually develop resistance to TKIs. The switch of EGFR downstream signaling from TKI-sensitive to TKI-insensitive is a critical mechanism-driving resistance to TKIs. Identification of potential therapies to target EGFR effectively is a potential strategy to treat TKI-resistant LUADs. In this study, we developed a small molecule diarylheptanoid 35d, a curcumin derivative, that effectively suppressed EGFR protein expression, killed multiple TKI-resistant LUAD cells in vitro, and suppressed tumor growth of EGFR-mutant LUAD xenografts with variant TKI-resistant mechanisms including EGFR C797S mutations in vivo. Mechanically, 35d triggers heat shock protein 70-mediated lysosomal pathway through transcriptional activation of several components in the pathway, such as HSPA1B, to induce EGFR protein degradation. Interestingly, higher HSPA1B expression in LUAD tumors associated with longer survival of EGFR-mutant, TKI-treated patients, suggesting the role of HSPA1B on retarding TKI resistance and providing a rationale for combining 35d with EGFR TKIs. Our data showed that combination of 35d significantly inhibits tumor reprogression on osimertinib and prolongs mice survival. Overall, our results suggest 35d as a promising lead compound to suppress EGFR expression and provide important insights into the development of combination therapies for TKI-resistant LUADs, which could have translational potential for the treatment of this deadly disease.

A herbal product inhibits carbon tetrachloride-induced liver fibrosis by suppressing the epidermal growth factor receptor signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Fuzheng Huayu formula (FZHY), composed of Salvia miltiorrhiza Bunge, Cordyceps sinensis, the seed of Prunus persica (L.) Batsch, the pollen of Pinus massoniana Lamb, Gynostemma pentaphyllum (Thunb.) Makino and the fruit of Schisandra chinensis (Turcz.) Baill, is a Chinese herbal compound with demonstrated clinical benefits in liver fibrosis (LF). However, its potential mechanism and molecular targets remain to be elucidated. AIM OF THE STUDY: This study was designed to evaluate the anti-fibrotic role of FZHY in hepatic fibrosis and to elucidate the potential mechanisms. MATERIALS AND METHODS: Network pharmacology was assayed to identify the interrelationships among compounds of FZHY, potential targets and putative pathways on anti-LF. Then the core pharmaceutical target for FZHY against LF was verified by serum proteomic analysis. Further in vivo and in vitro assays were performed to verify the prediction of the pharmaceutical network. RESULTS: The network pharmacology analysis revealed that a total of 175 FZHY-LF crossover proteins were filtered into a protein-protein interaction (PPI) network complex and designated as the potential targets of FZHY against LF, and the Epidermal Growth Factor Receptor (EGFR) signaling pathway was further explored according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Then analytical studies were validated by carbon tetrachloride (CCl4)-induced model in vivo. We found FZHY could attenuate CCl4-induced LF, especially decrease p-EGFR expression in α-Smooth Muscle Actin (α-SMA)-positive hepatic stellate cell (HSC) and inhibit the downstream of the EGFR signaling pathway, especially Extracellular Regulated Protein Kinases (ERK) signaling pathway in liver tissue. We further demonstrate that FZHY could inhibit Epidermal Growth Factor (EGF)-induced HSC activation, as well as the expression of p-EGFR and the key protein of the ERK signaling pathway. CONCLUSIONS: FZHY has a good effect against CCl4-induced LF. The action mechanism was associated with the down-regulation of the EGFR signaling pathway in activated HSCs.