Esophageal Squamous Cell Carcinoma Cell Lines Research Articles

Elucidating the role of CYFIP2 in conferring cisplatin resistance in esophageal squamous cell carcinoma

Cisplatin (CDDP) serves as a vital component in the chemotherapeutic approach to treat esophageal squamous cell carcinoma (ESCC). However, prolonged CDDP application frequently culminates in resistance, compromising therapeutic outcomes. Through genome-wide CRISPR library screening, our study elucidates the mechanisms underlying this resistance, pinpointing CYFIP2 as a pivotal mediator. Notably, the involvement CYFIP2 is characterized by pronounced autophagic activity and the modulation of multiple cellular pathways. Empirical validation was achieved by treating ESCC cell lines with CDDP, which resulted in an upsurge of CYFIP2 expression. The functional impact of CYFIP2 was further delineated through knockdown experiments, where a marked suppression in cell proliferation was observed, alongside a discernible decline in reactive oxygen species levels. This was complemented by a suite of assays and microscopic techniques, including GFP-LC3, mRFP-GFP-LC3, electron microscopy and western blot, which collectively affirmed the inhibitory effect of CYFIP2 knockdown on autophagic processes, particularly impeding autophagosome formation and their subsequent fusion with lysosomes. In vivo studies have also confirmed that CYFIP2 knockdown limits tumor progression and increases CDDP efficacy. Conclusively, our findings introduce CYFIP2 as a novel contributor to CDDP resistance in ESCC, underscoring its potential as a therapeutic target. This revelation not only deepens our understanding of resistance mechanisms but also paves the way for novel oncotherapeutic strategies, promising enhanced treatment efficacy against ESCC.

Implication of CCNG1 in radiosensitivity via the Wnt/β-catenin pathway in esophageal squamous cells

Esophageal cancer (EC) poses a substantial threat to human health. The development of radioresistance in esophageal cancer cells is a critical factor contributing to local treatment failure and an unfavorable prognosis in affected patients. A comprehensive analysis was performed using bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) data from esophageal squamous cell carcinoma (ESCC) samples. Radioresistant ESCC cell lines were generated to explore the functional role of CCNG1. Various techniques, including gene knockdown, flow cytometry, and apoptosis assays, were utilized to evaluate alterations in radiosensitivity, cell cycle progression, and cell survival in response to CCNG1 modulation. Elevated CCNG1 expression was associated with poor clinical outcomes in ESCC patients and contributed to various malignant phenotypes in ESCC cells. In radioresistant ESCC cell lines, CCNG1 knockdown markedly increased radiosensitivity, as demonstrated by enhanced G2/M phase arrest and apoptosis following radiation exposure. CellChat analysis indicated a correlation between CCNG1 and the Wnt/β-catenin signaling pathway, while western blot (WB) analysis confirmed that CCNG1 functions as a downstream effector of Wnt/β-catenin. Our study has identified CCNG1 as a key regulator of radiosensitivity in ESCC, mediated through its interaction with the Wnt/β-catenin signaling pathway. Targeting the Wnt/β-catenin/CCNG1 axis presents a promising therapeutic strategy to enhance the efficacy of radiotherapy in ESCC, potentially overcoming radioresistance and improving patient outcomes.

The radiosensitivity of niraparib tosylate to esophageal squamous cell carcinoma is stronger under hypoxia and higher-pressure conditions

Background: Radiotherapy is an effective method for esophageal squamous cell carcinoma (ESCC) treatment show reduced effectiveness in long-term due to reduced sensitivity of cancer cells to radiotherapy. Niraparib tosylate, a poly ADP-ribose polymerase (PARP) inhibitor may enhance the radiosensitivity of these cells. Hence, the present study was aimed to study the effects of niraparib tosylate on ESCC proliferation, apoptosis and cell cycle along with radiosensitivity enhancement efficiency. Materials and methods: ESCC cell lines, KYSE-30 were subjected to niraparib tosylate or irradiation treatments or combination of both. CCK8 and colony formation assays were performed to monitor cell growth status. Cell cycle and apoptosis level were investigated through flow cytometry. The expressions of targeted genes were detected at protein levels by western blot. Besides, xenografts were successfully established in immunocompromised mice. Student’s t-test was used to compare data and P < 0.05 was considered statistically significant. Results: Treatment with niraparib tosylate showed G2/M cycle arrest and apoptosis in KYSE-30 cells and the rate was observed to be more significant with combination therapy. These effects were further strengthened when cells were cultured under hypoxia and high atmospheric pressure. An enhanced susceptibility to radiotherapy was observed with niraparib tosylate combination. The homologous recombination related regulator, Rad51, showed remarkable upregulation in cancer cells exposed to combination of drug-radiation treatment. The tumor burden was also relieved in xenograft mouse models with combination of drug-radiation treatment, indicating the potential of niraparib tosylate use clinical cancer therapy. Conclusion: From the results, a novel function of niraparib tosylate can be established, impairing DNA damage repair efficiency to increase the susceptibility of ESCC to radiotherapy, resulting in cell apoptosis and G2/M cycle arrest in vitro and in vivo.

In Vivo Detection of Lymph Nodes Metastasis of ESCC Using CXCR4-Targeted Tracer [64Cu]Cu-NOTA-CP01.

Esophageal squamous cell carcinoma (ESCC) frequently exhibits skip metastasis to lymph nodes; however, non-invasive imaging techniques capable of directly visualizing metastatic lymph nodes (MLN) are still lacking. Although biopsy is the clinical standard method, it is invasive and poses risks to patient health. This study aims to detect MLN in an intralymphatic tumor metastasis model of ESCC using the CXCR4-targeted tracer [64Cu]Cu-NOTA-CP01. The CXCR4 expression in ESCC cell lines was assessed using Western blot and immunofluorescence. An intralymphatic tumor metastasis model was established and monitored using bioluminescence imaging (BLI). Small animal PET studies and biodistribution studies were performed to evaluate the specificity of [64Cu]Cu-NOTA-CP01 for MLN. Histopathology evaluation was employed to check for the presence of metastatic tumor cells and to assess CXCR4 expression levels in the metastatic lymph nodes. The intralymphatic tumor metastasis model was successfully established using the EC109/Luc cell line, which exhibited high CXCR4 expression, as verified by BLI. PET/CT imaging showed that the MLN uptakes in the baseline group were significantly inhibited in the blocking group. The ratios of MLN/muscle and MLN/blood werealso significantly higher in the baseline group than in the blocking group. Ex vivo PET/CT imaging of MLN corroborated the in vivo data. Biodistribution studies further supported the PET imaging studies, showing rapid clearance of the tracer from the blood and major organs, with significantly higher MLN/muscle and MLN/blood ratios in the baseline group compared to the blocking group. Histopathological staining verified positive CXCR4 expression in these lymph nodes containing metastatic tumor cells. Targeting CXCR4 with [64Cu]Cu-NOTA-CP01 for PET imaging of lymph nodes metastasis represents a promising approach that warrants further investigation. These findings have the potential to enhance diagnostic and therapeutic strategies for individuals with lymph nodes metastasis of ESCC.

AREG Upregulation in Cancer Cells via Direct Interaction with Cancer-Associated Fibroblasts Promotes Esophageal Squamous Cell Carcinoma Progression Through EGFR-Erk/p38 MAPK Signaling.

Cancer-associated fibroblasts (CAFs) are a key component of the tumor microenvironment and significantly contribute to the progression of various cancers, including esophageal squamous cell carcinoma (ESCC). Our previous study established a direct co-culture system of human bone marrow-derived mesenchymal stem cells (progenitors of CAFs) and ESCC cell lines, which facilitates the generation of CAF-like cells and enhances malignancy in ESCC cells. In this study, we further elucidated the mechanism by which CAFs promote ESCC progression using cDNA microarray analysis of monocultured ESCC cells and those co-cultured with CAFs. We observed an increase in the expression and secretion of amphiregulin (AREG) and the expression and phosphorylation of its receptor EGFR in co-cultured ESCC cells. Moreover, AREG treatment of ESCC cells enhanced their survival and migration via the EGFR-Erk/p38 MAPK signaling pathway. Immunohistochemical analysis of human ESCC tissues showed a positive correlation between the intensity of AREG expression at the tumor-invasive front and the expression level of the CAF marker FAP. Bioinformatics analysis confirmed significant upregulation of AREG in ESCC compared with normal tissues. These findings suggest that AREG plays a crucial role in CAF-mediated ESCC progression and could be a novel therapeutic target for ESCC.

Oxymatrine inhibits migration and invasion of esophageal squamous cell carcinoma cell lines via the MEK1/ERK/β-catenin pathway

Esophageal, cancer is a prevalent malignant tumour of the digestive system in China, and esophageal squamous cell carcinoma (ESCC) accounts for 90 % of all esophageal cancer cases. Currently, the primary treatment involves surgical resection combined with postoperative radiotherapy. In this study, we used two ESCC cell lines to determine whether oxymatrine (OMT) inhibits ESCC, whether the mechanism involves the MEK1/ERK/β-catenin pathway, and how OMT modulates this pathway to affect the development of ESCC. The effects of OMT treatment were monitored with Cell Counting Kit-8 (CCK-8) assays as well as with clony formation, migration and invasion, wound healing, Hoechst 33258, and Western blot analyses. The relationship between OMT and the target was also evaluated by molecular docking and cell stability experiments. These findings suggest that ESCC development and metastasis may be inhibited by OMT and that OMT targets MEK1 through the ERK/β-catenin/EMT pathway to suppress ESCC cell migration and invasion. In addition, in vivo studies confirmed that OMT can inhibit the growth of ESCC cell lines in NOG mice without causing damage to other organs. In conclusion, in vitro experiments, revealed that OMT prevents the migration and invasiveness of ESCC cells by inhibiting the ERK/β-catenin/EMT pathway and thus targeting MAP2K1 (MEK1) in ESCC.

TRIM33 promotes glycolysis through regulating P53 K48-linked ubiquitination to promote esophageal squamous cell carcinoma growth

Esophageal squamous cell carcinoma (ESCC) is a common fatal malignant tumor of the digestive tract; however, its pathogenic mechanism is unknown and lacks specific molecular diagnosis and treatment. Therefore, it is particularly important to identify new tumor biomarkers to enhance the early diagnosis and molecular-targeted therapy of ESCC. Here, we found that the E3 ubiquitin ligase Tripartitemotif-containing33 (TRIM33) is highly expressed in ESCC tissues and cell lines, and is associated with adverse clinical outcomes. We determined that TRIM33 drives aerobic glycolysis to promote tumor growth in vivo and in vitro. In terms of mechanism, TRIM33 binds to p53 to inhibit its stability and promote the expression of downstream glycolysis target genes GLUT1, HK2, PKM2, and LDHA. In addition, TRIM33 promotes the polyubiquitination of P53 K48-linked and proteasome degradation. Further studies have shown that the K351 site of P53 is the key site mediating the ubiquitination of P53 K48-linked to promote aerobic glycolysis in ESCC and tumor cell growth. Our results reveal that the TRIM33-P53 signal axis regulates glycolysis during ESCC and may provide a new perspective for the diagnosis and treatment of ESCC.

EIF4A3-mediated oncogenic circRNA hsa_circ_0001165 advances esophageal squamous cell carcinoma progression through the miR-381-3p/TNS3 pathway

Esophageal squamous cell carcinoma (ESCC) remains a major clinical challenge due to its poor prognosis and the scarcity effective therapeutic targets. Circular RNAs (circRNAs) are crucial in cancer progression. In this study, high-throughput sequencing was employed to profile ESCC tissues, revealing that hsa_circ_0001165 is notably elevated in both ESCC tumor samples and cell lines, with its expression is positively associated with patients' TNM staging. Knockdown of hsa_circ_0001165 resulted in reduced malignant biological behavior of ESCC cells in vitro and also inhibited tumor growth in vivo. Mechanism experimental analysis found that hsa_circ_0001165 expression is positively enhanced by eukaryotic translation initiation factor 4A3 (EIF4A3). Hsa_circ_0001165 acts as a miRNA sponge for miR-381-3p, increasing the expression of tensin-3 (TNS3) through a series of related mechanism assays include dual-luciferase reporter gene, RNA Immunoprecipitation and RNA-pulldown. The downregulation in miR-381-3p expression was observed in ESCC tissues, and the cell proliferation, invasion, and migration of ESCC were suppressed. The upregulated expression of hsa_circ_0001165 modulates the miR-381-3p/TNS3 axis and promotes aggressive phenotypes of ESCC. Hsa_circ_0001165 is regarded as a encouraging biomarker and potential therapeutic target for ESCC, presenting innovative options for both diagnostic and treatment approaches.

TMT-Based Quantitative Proteomic Profiling of Human Esophageal Cancer Cells Reveals the Potential Mechanism and Potential Therapeutic Targets Associated With Radioresistance.

The recurrence of esophageal squamous cell carcinoma (ESCC) in radiation therapy treatment presents a complex challenge due to its resistance to radiation. However, the mechanism underlying the development of radioresistance in ESCC remains unclear. In this study, we aim to uncover the mechanisms underlying radioresistance in ESCC cells and identify potential targets for radiosensitization. We established two radio-resistant cell lines, TE-1R and KYSE-150R, from the parental ESCC cell lines TE-1 and KYSE-150 through fractionated irradiation. A TMT-based quantitative proteomic profiling approach was applied to identify changes in protein expression patterns. Cell Counting Kit-8, colony formation, γH2AX foci immunofluorescence and comet assays were utilized to validate our findings. The downstream effectors of the DNA repair pathway were confirmed using an HR/NHEJ reporter assay and Western blot analysis. Furthermore, we evaluated the expression of potential targets in ESCC tissues through immunohistochemistry combined with mass spectrometry. Over 2,000 proteins were quantitatively identified in the ESCC cell lysates. A comparison with radio-sensitive cells revealed 61 up-regulated and 14 down-regulated proteins in the radio-resistant cells. Additionally, radiation treatment induced 24 up-regulated and 12 down-regulated proteins in the radio-sensitive ESCC cells. Among the differentially expressed proteins, S100 calcium binding protein A6 (S100A6), glutamine gamma-glutamyltransferase 2 (TGM2), glycogen phosphorylase, brain form (PYGB), and Thymosin Beta 10 (TMSB10) were selected for further validation studies as they were found to be over-expressed in the accumulated radio-resistant ESCC cells and radio-resistant cells. Importantly, high S100A6 expression showed a positive correlation with cancer recurrence in ESCC patients. Our results suggest that several key proteins, including S100A6, TGM2, and PYGB, play a role in the development of radioresistance in ESCC. Our results revealed that several proteins including Protein S100-A6 (S100A6), Protein-glutamine gamma-glutamyltransferase 2 (TGM2), Glycogen phosphorylase, brain form (PYGB) were involved in radio-resistance development. These proteins could potentially serve as biomarkers for ESCC radio-resistance and as therapeutic targets to treat radio-resistant ESCC cells.

Downregulation of chemokine (C‑C motif) ligand 5 induced by a novel 8‑hydroxyquinoline derivative (91b1) suppresses tumor invasiveness in esophageal carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a particularly aggressive form of cancer with high mortality. In the present study, a novel 8‑hydroxyquinoline derivative (91b1) was investigated for its anticancer activities in ESCC along with its associated mechanisms. The in vitro cytotoxic effect of 91b1 were evaluated across five ESCC cell lines using MTS assay, with cisplatin serving as a comparative standard. Changes in gene expression profile were identified by cDNA microarray and further validated by qualitative PCR and immunostaining. Additionally, protein levels of the most notably downregulated target in archival ESCC samples were also studied. 91b1 demonstrated comparable anticancer effect with cisplatin. Notably, chemokine ligand 5 (Ccl5) was identified as the most substantially downregulated gene, with its suppression at both mRNA and protein expression in ESCC cells, exhibiting a dose‑dependent manner. The recombinant human protein of CCL5 enhanced the invasion of ESCC cells using the Transwell assay. The upregulation of CCL5 protein was also detected in 50% of ESCC cell lines. CCL5 was also overexpressed in 76.9% of ESCC specimens. The overall results indicated that 91b1 could effectively induce anticancer effect on ESCC cells through downregulating CCL5 expression with suppression of tumor invasion. Overall, these findings suggested that 91b1 effectively inhibited ESCC cell proliferation and tumor invasion by downregulating CCL5 expression, highlighting its potential as a therapeutic agent for ESCC treatment.

Induction of LARP1B under endoplasmic reticulum stress and its regulatory role in proliferation of esophageal squamous cell carcinoma

Endoplasmic Reticulum Stress (ER stress) is a series of cellular responses activated in response to misfolded and unfolded protein accumulation and calcium imbalance in the ER lumen. Cumulating evidence emphasized the crucial involvement of ER stress in cell survival, death, and proliferation. However, the precise process remained obscure, especially in esophageal squamous cell carcinoma (ESCC). In the present study, LARP1B was detected to be one of the genes with significant differential expression in the ER stress ESCC cell model by RNA sequencing. ESCC cells exposed to ER stress stimulants (thapsigargin and tunicamycin) showed increased expression levels of LARP1B. ER stress initiated the expression of LARP1B through activation of the ERN1-XBP1 pathway, with XBP1 acting as a transcription factor to boost LARP1B transcription. Up-regulation of LARP1B was detected in ESCC tissues and cell lines. Suppression of LARP1B effectively curtailed the growth of cells and hindered the progression of the cell cycle. By detecting the expression of some genes closely related to proliferation and cell cycle regulation, CCND1 was identified as the main contributor to the cell proliferation induced by LARP1B. As an RNA-binding protein, LARP1B has the capability to attach to CCND1 mRNA, thereby increasing its stability. Inhibiting CCND1 might partially counterbalance the proliferation-promoting impact of LARP1B overexpression on ESCC cells. These findings indicate that, upon ER stress, up-regulation of LARP1B, triggered by ERN1-XBP1 pathway, facilitates proliferation of ESCC cells through enhancing the mRNA stability of CCND1, and LARP1B may be used as a potential therapeutic target of ESCC.

Expression profile and function of secretogranin V, and its effects on the malignant behavior of esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is recognized as one of the most aggressive cancers with a poor prognosis. Global expression profiling was conducted on primary ESCC tissues with distant metastases. We investigated the identification of secretogranin V (SCG5) as a promising biomarker for the detection and assessment of ESCC. SCG5 transcription levels were evaluated in 21 ESCC cell lines. Small interfering RNA-mediated knockdown experiments validated SCG5's roles in cell invasion, proliferation, and migration. We utilized a mouse subcutaneous xenograft model to assess tumor growth. SCG5 expression was measured in 164 ESCC tissues by quantitative reverse transcription quantitative polymerase chain reaction, and its association with clinicopathological parameters was investigated. SCG5 protein levels were assessed in surgically resected tissues from 177 patients with ESCC using a tissue microarray. The mRNA expression levels of SCG5 varied widely in ESCC cell lines. The in vitro cell invasion, proliferation, and migration of ESCC cells were suppressed by the knockdown of SCG5. Mouse xenograft models revealed that tumor growth was reduced by small interfering RNA-mediated SCG5 knockdown. Analysis of clinical samples demonstrated that SCG5 mRNA was expressed in ESCC compared to adjacent normal esophageal tissues. High SCG5 mRNA expression was linked to significant decreases in overall and disease-specific survival. Furthermore, SCG5 protein expression was linked to a decrease in disease-specific survival and disease-free survival. The expression of the SCG5 was significantly associated with disease-specific survival, suggesting that SCG5 may play a significant role as a diagnostic and prognostic biomarker for ESCC.

The m6A modification of ACSL4 mRNA sensitized esophageal squamous cell carcinoma to irradiation via accelerating ferroptosis.

Radioresistance is a major obstacle for the therapy of esophageal squamous cell carcinoma (ESCC) and lead to a poor prognosis. Ferroptosis is supposed to be responsible for radioresistance. However, the ferroptosis-induced radioresistance in ESCC and its related regulatory mechanisms are not yet fully understood. In this study, human ESCC cell line and the corresponding radioresistance cells were irradiated with 6 megavolts (MV) X-ray. It was showed that irradiation led to less ferroptosis in radioresistant ESCC cells as compared to the parental cells, as depicted by transmission electron microscopy, intracellular Fe2+ iron contents, lipid peroxidation, and expression of COX2. The increase of ASCL4 expression levels in radioresistant cells after radiotherapy was smaller than that in the parental cells. ACSL4 overexpression significantly enhanced ferroptosis. The fold increase in ACSL4 m6A modification in the radioresistant cells was significantly smaller than that in the parental cells as detected by methylated RNA immunoprecipitation with qRT-PCR. METTL14 overexpression accelerated ferroptosis induced by irradiation via upregulating m6A modification of ACSL4 mRNA. In conclusions, ferroptosis ablation was responsible for the radioresistant of ESCC. The METTL14-mediated m6A modification of ACSL4 mRNA sensitized ESCC to irradiation via accelerating ferroptosis. This study sheds new light on our understanding of radioresistant in ESCC, and provides potential strategies for ESCC radiotherapy.

FAM83D promotes the progression of 4NQO-induced esophageal carcinoma via inhibiting FBWX7

The present study aimed to explore the expression and regulatory role of FAM83D in the different developmental stages of esophageal squamous cell carcinoma (ESCC) to determine the effect of FAM83D on the proliferation, migration, and invasion of ESCC cells and to elucidate its underlying molecular mechanism. Immunohistochemistry (IHC) analysis revealed that the expression of FAM83D was obviously elevated in ESCC tissues compared to adjacent normal tissues. Furthermore, the FAM83D levels was positively correlated with tumor size, TNM stage, T stage, and N stage, while it was negatively correlated with FBXW7 expression, Karnofsky Performance Status (KPS) score, and survival rate. Subsequently, ESCC cell lines with low FAM83D expression were constructed using RNA interference technology to investigate the impact of FAM83D on the biological behavior of ESCC cells. Silencing of FAM83D inhibited the proliferation and migration of ESCC cells but promoted apoptosis. Furthermore, a reduction in FAM83D expression may also induce cell cycle arrest at the G0/G1 phase and regulate the expression of proteins related to epithelial-mesenchymal transition (EMT), the cell cycle, and apoptosis. Further research indicated that silencing FAM83D led to the upregulation of FBXW7 expression. These results suggested that FAM83D may exert its effects on ESCC by downregulating FBXW7. Additionally, using a 4NQO solution in the drinking water to establish an ESCC mouse model, IHC analysis revealed that FAM83D expression levels were positively correlated with the pathological grade of esophageal lesions in the mice and negatively correlated with the expression levels of FBXW7 and E-cadherin. The above results demonstrated that FAM83D may facilitate the progression of ESCC by negatively regulating FBXW7 expression and that FAM83D could represent a promising therapeutic target for ESCC.

Impaired TGF-β signaling via AHNAK family mutations elicits an esophageal cancer subtype with sensitivities to genotoxic therapy and immunotherapy

BackgroundGenome instability (GI) is a hallmark of esophageal squamous cell carcinoma (ESCC) while factors affecting GI remain unclear.MethodsHere, we aimed to characterize genomic events representing specific mechanisms of GI based on 201 ESCC samples and validated our findings at the patient, single-cell and cancer cell-line levels, including a newly generated multi-omics dataset of the trial NCT04006041.ResultsA two-gene (AHNAK and AHNAK2) mutation signature was identified to define the “AHNAK1/2-mutant” cancer subtype. Single-cell-assisted multi-omics analysis showed that this subtype had a higher neoantigen load, active antigen presentation, and proficient CD8 + T cell infiltrations, which were validated at pan-cancer levels. Mechanistically, AHNAK1/2-mutant ESCC was characterized by impaired response of TGF-β and the inefficient alternative end-join repair (Alt-EJ) that might promote GI. Knockdown of AHNAK in ESCC cell lines resulted in more Alt-EJ events and increased sensitivities to cisplatin. Furthermore, this two-gene signature accurately predicted better responses to DNA-damaging therapy in various clinical settings (HR ≈ 0.25). The two-gene signature predicted higher pCR rates in ESCCs receiving neoadjuvant immunotherapy-involved treatment. Finally, a molecular classification scheme was built and outperformed established molecular typing models in the prognosis stratification of ESCC patients.ConclusionOur study extended our understanding of the AHNAK family in promoting GI and selecting treatment responders of ESCC.

317. PD-L1 DYNAMICS DURING THE CISPLATIN-INDUCED ACQUIRED RESISTANCE PROCESS IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background Immunotherapy combined with chemotherapy has been the first-line treatment and the most widely-used neoadjuvant regimen in esophageal squamous cell carcinoma (ESCC). Resistance to chemotherapy is an inevitable clinical problem, however, the impact of chemoresistance on immunotherapy efficacy remains unclear. This study aimed to investigate the impact of chemoresistance formation on PD-L1 dynamic changes both in vivo and in vitro during the construction of cisplatin-resistant ESCC models, with the goal of exploring the potential influence of chemoresistance on immunotherapy. Methods For in vivo model, fluorescent-labeled ESCC cells (AKR) were implanted into C57 mice, followed by cisplatin administration for six cycles. Surviving tumor cells were isolated using flow cytometry, and reinjected to establish cisplatin-resistant model. Tumors were harvested to evaluate PD-L1 expression by immunohistochemistry. For in vitro model, ESCC cell lines (TE-1, KYSE150) received low-dose cisplatin for 48h. After three cycles, resistance index (RI, RI=IC50 of drug-expose cell/IC50 of parental cell) was determined by CCK8 assay. The process was repeated with escalating cisplatin doses until resistant cell lines were established (RI>5). PD-L1 expression was measured using RT-qPCR/Western-Blot after each generation. Results In vivo (Figure A), cisplatin-resistant tumor exhibited elevated PD-L1 expression compared to control group (H-score: 22.17 vs 2.09, p<0.001). In vitro (Figure B), PD-L1 expression exhibited an initial increase, followed by a gradual decrease during the process of cisplatin-induced resistance. Specifically, in early stages of cisplatin-resistance in TE-1 cells, PD-L1 mRNA expression rose 4.9 times, consistently paralleled by an elevation in protein level. Subsequently, PD-L1 expression gradually decreased in both mRNA and protein levels. KYSE150 cells exhibited a trend of upregulation in PD-L1 expression in the early stages of cisplatin resistance but later decreased, returning to parental cell levels. Conclusion Under in vivo conditions, acquired cisplatin-resistance in ESCC cells significantly upregulated PD-L1 expression, indicating a potential mechanism for PD-L1-mediated immune escape and its impact on immunotherapy efficacy. However, under in vitro conditions, no consistent trend in PD-L1 expression was observed during the acquisition of cisplatin resistance. This suggests a potentially crucial role of the immune system involved in the chemoresistance regulatory mechanism. Further investigations are needed to explore the impact of chemoresistance on tumor immunology.

582. LOW EXPRESSION OF FRG1 PROMOTES MIGRATION AND INVASION IN ESOPHAGEAL CANCER

Abstract Purpose Distant metastasis is the primary cause of mortality among patients with esophageal cancer. Although FRG1 is known to play a role in the metastasis of various cancers, its specific function in esophageal squamous cell carcinoma (ESCC) has yet to be elucidated. In this study, we aimed to explore the role and potential molecular mechanism of FRG1 in the metastasis of ESCC. Methods Whole-exome sequencing was performed in ESCC patients who experienced distant metastasis (DM group) and those without metastasis within two years (non-DM group). Bioinformatics analysis and Immunohistochemistry (IHC) validation were conducted. In vitro, FRG1-overexpressed ESCC cell lines were established with lentivirus and validated by western blots. The wound-healing assay, transwell migration and invasion assay were performed in esophageal cancer cell lines. Additionally, RNA sequencing was conducted in ESCC cells to identify potential pathways involved. Results Mutations in FRG1 were more frequently observed in DM group compared to those in non-DM group. IHC revealed that the expression of FRG1 in DM group was significantly lower than non-DM group. In vitro, our results showed that ESCC cells with low FRG1 expression exhibited enhanced migration and invasion capabilities. Conversely, overexpression of FRG1 inhibited migration and invasion in ESCC cells. Mechanistically, RNA sequencing analysis showed a total of 93 differential expression genes between FRG1-overexpressed cells and the negative control. Notably, most differential genes were mainly enriched in the PPAR pathway and tyrosine metabolism pathway. Conclusion Our findings suggest that low FRG1 expression in patients may be indicative of rapid distant metastasis. The significant impact of FRG1's abnormal expression on the migration and invasion of ESCC cells highlights its potential as a therapeutic target for treating esophageal squamous cell carcinoma.

Early Diagnostic Markers for Esophageal Squamous Cell Carcinoma: Copy Number Alteration Gene Identification and cfDNA Detection

The high mortality rate of esophageal squamous cell carcinoma (ESCC) is exacerbated by the absence of early diagnostic markers. The pronounced heterogeneity of mutations in ESCC renders copy number alterations (CNAs) more prevalent among patients. The identification of CNA genes within esophageal squamous dysplasia (ESD), a precancerous stage of ESCC, is crucial for advancing early detection efforts. Utilization of liquid biopsies via droplet-based digital PCR (ddPCR) offers a novel strategy for detecting incipient tumor traces. This study undertook a thorough investigation of CNA profiles across ESCC development stages, integrating data from existing databases and prior investigations to pinpoint and confirm CNA markers conducive to early detection of ESCC. Targeted sequencing was employed to select potential early detection genes, followed by the establishment of prediction models for ESCC early detection using ddPCR. Our analysis revealed widespread CNAs during the ESD stage, mirroring the CNA landscape observed in ESCC. A total of 40 CNA genes were identified as highly frequent in both ESCC and ESD lesions, through a comprehensive gene-level CNA analysis encompassing ESD and ESCC tissues, ESCC cell lines, and pan-cancer data sets. Subsequent validation of 5 candidate markers via ddPCR underscored the efficacy of combined predictive models encompassing PIK3CA, SOX2, EGFR, MYC, and CCND1 in early ESCC screening, as evidenced by the area-under-the-curve values exceeding 0.92 (P < .0001) across various detection contexts. The findings highlighted the significant utility of CNA genes in the early screening of ESCC, presenting robust models that could facilitate early detection, broad-scale population screening, and adjunctive diagnosis.

Mechanism investigation of Forsythoside A against esophageal squamous cell carcinoma in vitro and in vivo

ABSTRACT Context Forsythoside A (FSA) was extracted from Forsythia suspensa, a traditional Chinese medicine, which has been demonstrated to exert anti-inflammatory, antibacterial, and other pharmacological effects. However, the anticancer effect of FSA in esophageal squamous cell carcinoma (ESCC) has not been documented. Objective The present study aimed to elucidate the mechanism of FSA against ESCC. Materials and methods Network pharmacology and molecular docking were employed to predict the mechanism. FSA was utilized to treat ESCC cell lines KYSE450 and KYSE30, followed by CCK-8 assay, cell cloning formation assay, flow cytometry, Western blot, RNA-seq analysis, and subsequent in vivo experiments. Results Network pharmacology and molecular docking predicted that the therapeutic effect of FSA in ESCC is mediated through proteins such as BCL2 and BAX, influencing KEGG pathways associated with apoptosis. In vitro experiments showed that FSA inhibited cell proliferation and plate clone formation, promoted cell apoptosis and impacted the cell cycle distribution of G2/M phase by regulating BCL2, BAX, and p21. Further RNA-seq in KYSE450 cells showed that FSA regulated the expression of 223 genes, specifically affecting the biological process of epidermal development. In vivo experiments showed that gastric administration of FSA resulted in notable reductions in both tumor volume and weight by regulating BCL2, BAX, and p21. 16S rRNA sequencing showed that FSA led to significant changes of beta diversity. Abundance of 11 specific bacterial taxa were considerably changed following administration of FSA. Conclusions This study presents a novel candidate drug against ESCC and establishes a foundation for future clinical application.

Ferroptosis suppressor genes are highly expressed in esophageal cancer to inhibit tumor cell ferroptosis

To explore the role of ferroptosis-related genes in regulating ferroptosis of esophageal squamous cell carcinoma (ESCC). ESCC datasets GSE161533 and GSE20347 were downloaded from the Gene Expression Omnibus (GEO) to identify the differentially expressed genes (DEGs) using R software. ESCC ferroptosis-related genes obtained by intersecting the DEGs with ferroptosis-related genes from FerrDb were analyzed using GO and KEGG analyses, protein-protein interaction (PPI) network analysis, and core gene identification through Cytoscape. The identified ferroptosis suppressor genes were validated using TCGA database, and their expression levels were detected using RT-qPCR in cultured normal esophageal cells and ESCC cells. Six ferroptosis suppressor genes (RRM2, GCLC, TFRC, TXN, SLC7A11, and EZH2) were downregulated with siRNA in ESCC cells, and the changes in cell proliferation and apoptosis were assessed with CCK8 assay and flow cytometry; Western blotting was performed to examine the changes in ferroptosis progression of the cells. We identified a total of 58 ESCC ferroptosis-related genes, which involved such biological processes as glutathione transmembrane transport, iron ion transport, and apoptosis and the ferroptosis, glutathione metabolism, and antifolate resistance pathways. The PPI network included 54 nodes and 74 edges with a clustering coefficient of 0.522 and PPI enrichment P<0.001. Cytoscape identified 6 core ferroptosis suppressor genes (RRM2, TFRC, TXN, EZH2, SLC7A11, and GCLC), which were highly expressed in ESCC tissues in the TCGA dataset and in ESCC cell lines. Downregulating these genes in ESCC TE1 cells significantly inhibited cell proliferation, promoted cell apoptosis, reduced the expression levels of ferroptosis markers GPX4 and FIH1, and increased the expression of ACSL4. High expression of ferroptosis suppressor genes in ESCC may cause arrest of ferroptosis progression to facilitate tumor development, and inhibiting these genes can restore ferroptosis and promote cell apoptosis, suggesting their value as potential therapeutic targets for ESCC.