Activation of growth factor receptors in esophageal cancer--implications for therapy

RSPO2-associated mitochondrial metabolism defines molecular subtypes with distinct clinical and immune features in esophageal cancer

BACKGROUND

Esophageal cancer is a highly aggressive malignancy with limited treatment options and poor prognosis. The identification of novel molecular subtypes and therapeutic targets is crucial for improving clinical outcomes.

METHOD

In this study, we investigated the role of R-spondin 2 (RSPO2) in esophageal cancer and its association with mitochondrial metabolism. Using bioinformatics analysis of publicly available datasets, we identified a panel of RSPO2-related mitochondrial metabolism genes and their expression patterns in esophageal cancer. Based on these genes, we stratified esophageal cancer patients into distinct molecular subtypes with different survival rates, immune cell infiltration profiles, and drug sensitivities.

RESULTS

Our findings suggest that RSPO2-related mitochondrial metabolism genes may serve as potential therapeutic targets and prognostic markers for esophageal cancer. These genes play an important role in the prognosis, immune cell infiltration and drug sensitivity of esophageal cancer.

CONCLUSION

The identified molecular subtypes provide valuable insights into the underlying molecular mechanisms of esophageal cancer and could guide personalized treatment strategies in the future.

GEAMP, a novel gastroesophageal junction carcinoma cell line derived from a malignant pleural effusion

Gastroesophageal junction (GEJ) cancer remains a clinically significant disease in Western countries due to its increasing incidence, which mirrors that of esophageal cancer, and poor prognosis. To develop novel and effective approaches for prevention, early detection, and treatment of patients with GEJ cancer, a better understanding of the mechanisms driving pathogenesis and malignant progression of this disease is required. These efforts have been limited by the small number of available cell lines and appropriate preclinical animal models for in vitro and in vivo studies. We have established and characterized a novel GEJ cancer cell line, GEAMP, derived from the malignant pleural effusion of a previously treated GEJ cancer patient. Comprehensive genetic analyses confirmed a clonal relationship between GEAMP cells and the primary tumor. Targeted next-generation sequencing identified 56 nonsynonymous alterations in 51 genes including TP53 and APC, which are commonly altered in GEJ cancer. In addition, multiple copy-number alterations were found including EGFR and K-RAS gene amplifications and loss of CDKN2A and CDKN2B. Histological examination of subcutaneous flank xenografts in nude and NOD-SCID mice showed a carcinoma with mixed squamous and glandular differentiation, suggesting GEAMP cells contain a subpopulation with multipotent potential. Finally, pharmacologic inhibition of the EGFR signaling pathway led to downregulation of key downstream kinases and inhibition of cell proliferation in vitro. Thus, GEAMP represents a valuable addition to the limited number of bona fide GEJ cancer cell lines.

Evolving Management Strategies for Metastatic Esophageal and Gastroesophageal Junction Adenocarcinoma

Metastatic or unresectable esophageal and gastroesophageal junction adenocarcinoma represent a devastating disease with 5-year survival rate of <5%. Although cytotoxic chemotherapy with platinum-doublet-based regimens is initially effective, patients inevitably progress. Patients often decline rapidly after this initial progression, making later lines of therapy a challenge to successfully administer There have been multiple efforts to incorporate biologic agents, targeting pathways known to be dysregulated in esophageal adenocarcinoma and gastroesophageal junction adenocarcinoma, into existing chemotherapy backbones. Other than therapeutics targeting human epidermal growth factor receptor-2 (HER2) and vascular endothelial growth factor receptor (VEGFR), other strategies have failed. Given the mixed success of biologic agents, along with the promise of immunotherapy to generate durable and sometimes complete responses, immune-agent based trials are a major area of interest for patients with this disease. Checkpoint inhibitors blocking programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have demonstrated modest single-agent efficacy in patients with progressive esophageal adenocarcinoma and gastroesophageal junction adenocarcinoma. However, other approaches such as novel checkpoint combinations, vaccine-based approaches and autologous T cells hold more promise to change the trajectory of disease.

Genetic polymorphisms of ATG5 predict survival and recurrence in patients with early-stage esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a deadly disease with high risk of tumor recurrence even among patients with an early pathologic stage of tumor. In the current study, we investigate the association between 20 SNPs of the ATG5 gene and prognosis of patients with early-stage ESCC. A total of 305 patients diagnosed with early-stage ESCC were enrolled in the study and randomly assigned to a training set (n=93) or replication set (n=212). The genotypes of candidate SNPs (single nucleotide polymorphisms) within ATG5 were analyzed and correlated with the prognosis of ESCC patients. We repeatedly demonstrated that 3 SNPs in ATG5, rs1322178, rs3804329, and rs671116, were significantly correlated with the prognosis of patients with early-stage ESCC (HR[95 % CI]=2.01[1.19-3.40], p=0.009 for ATG5: rs1322178; HR[95 % CI]=1.88 [1.08-3.26], p=0.025 for ATG5:rs3804329; HR[95 % CI]=1.73[1.24-2.42], p=0.001 for ATG5:rs671116, in combined group). Both rs1322178 and rs3804329 can predict early distant metastasis of patients. Furthermore, increased expression of ATG5 was observed in ESCC tumor tissue as compared to adjacent normal tissue. Moreover, higher levels of ATG5 expression in both normal and tumor tissues exhibited a trend to correlate with poor prognosis of patients. However, the expression of ATG5 did not correlate with these 3 relevant prognostic SNPs. We concluded that hereditary genetic polymorphisms and gene expression of ATG5 can serve as prognostic predictors of patients with early-stage ESCC.

APIO-EE-9 is a novel Aurora A and B antagonist that suppresses esophageal cancer growth in a PDX mouse model

Esophageal cancer (EC) is one of the most aggressive malignancies of the upper aerodigestive tract. Over the past three decades, with advances in surgical techniques and treatment, the prognosis of esophageal cancer has only slowly improved. Thus identifying novel molecular targets and developing therapeutic agents are critical. Aurora kinases play a crucial role in mitosis and selective inhibitors might provide an effective therapeutic treatment for cancer. However, the role of Aurora kinases in EC is still inadequately studied. Here, we identified a novel compound, referred to as APIO-EE-9, which inhibits growth and colony formation and induces apoptosis of esophageal cancer cells. Using computer modeling, we found that APIO-EE-9 interacted with both Aurora A and B in the ATP-binding pocket. APIO-EE-9 inhibited both Aurora A and B kinase activities in a dose-dependent manner. Treatment with APIO-EE-9 substantially reduced the downstream Aurora kinase phosphorylation of histone H3 (Ser10), resulting in formation of multiple nuclei and centrosomes. Additionally, esophageal cancer cells expressing shAurora A or shAurora B kinase exhibited a dramatic reduction in proliferation and colony formation. Injection of these cells as xenografts in mice reduced tumor formation compared to wildtype cells. Importantly, APIO-EE-9 significantly decreased the size of esophageal patient-derived xenograft (PDX) tumors implanted in SCID mice. These results demonstrated that APIO-EE-9 is a specific Aurora kinase inhibitor that could be developed as a therapeutic agent against esophageal cancer.

ADAM10-mediated release of heregulin confers resistance to trastuzumab by activating HER3

Receptor tyrosine kinases of the HER-family are involved in the development and progression of multiple epithelial tumors, and have consequently become widely used targets for new anti-cancer therapies. Trastuzumab, an antibody against HER2, has shown potent growth inhibitory effects on HER2 overexpressing tumors, including gastro-esophageal cancer, however, resistance to this therapy is inevitable. Unfortunately, a paucity of data on the cellular mechanisms of resistance to targeted therapeutic agents exists in esophageal adenocarcinoma. Using primary established HER2-overexpressing cultures and patient-derived xenograft models, we now reveal a novel resistance mechanism to trastuzumab in esophageal cancer: In response to trastuzumab, both HER3 and the metalloprotease ADAM10 are simultaneously upregulated. The proteolytic activity of the latter then releases the HER3 ligand heregulin from the cell surface to activate HER3 and confer resistance to trastuzumab by inducing compensatory growth factor receptor signaling. Blocking either HER3 or ADAM10 effectively reverts the acquired resistance to trastuzumab. Our data thus provide strategies to inhibit this signaling and circumvent resistance to trastuzumab.

The tumor microenvironment in esophageal cancer

Esophageal cancer is a deadly disease, ranking sixth among all cancers in mortality. Despite incremental advances in diagnostics and therapeutics, esophageal cancer still carries a poor prognosis, and thus there remains a need to elucidate the molecular mechanisms underlying this disease. There is accumulating evidence that a comprehensive understanding of the molecular composition of esophageal cancer requires attention to not only tumor cells but also the tumor microenvironment, which contains diverse cell populations, signaling factors, and structural molecules that interact with tumor cells and support all stages of tumorigenesis. In esophageal cancer, environmental exposures can trigger chronic inflammation, which leads to constitutive activation of pro-inflammatory signaling pathways that promote survival and proliferation. Anti-tumor immunity is attenuated by cell populations such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), as well as immune checkpoints like programmed death-1 (PD-1). Other immune cells such as tumor-associated macrophages can have other pro-tumorigenic functions, including the induction of angiogenesis and tumor cell invasion. Cancer-associated fibroblasts secrete growth factors and alter the extracellular matrix (ECM) to create a tumor niche and enhance tumor cell migration and metastasis. Further study of how these TME components relate to the different stages of tumor progression in each esophageal cancer subtype will lead to development of novel and specific TME-targeting therapeutic strategies, which offer considerable potential especially in the setting of combination therapy.

Genomics of Esophageal Cancer and Biomarkers for Early Detection

In-depth molecular characterization of esophageal oncogenesis has improved over the recent years. Advancement in molecular biology and bioinformatics has led to better understanding of its genomic landscape. More specifically, analysis of its pathogenesis at the genetic level has uncovered the involvement of a number of tumor suppressor genes, cell cycle regulators, and receptor tyrosine kinases. Due to its poor prognosis, the development of clinically applicable biomarkers for diagnosis, progression, and treatment has been the focus of many research studies concentrating on upper gastrointestinal malignancies. As in other cancers, early detection and subsequent intervention of the preneoplastic condition significantly improves patient outcomes. Currently, clinically approved surveillance practices heavily depend on expensive, invasive, and sampling-error-prone endoscopic procedures. There is, therefore, a great demand to establish clearly reliable biomarkers that could identify those patients at higher risk of neoplastic progression and hence would greatly benefit from further monitoring and/or intervention. This chapter will present the most recent advances in the analysis of the esophageal cancer genome serving as basis for biomarker development.

1H-NMR based metabonomic profiling of human esophageal cancer tissue

BACKGROUND

The biomarker identification of human esophageal cancer is critical for its early diagnosis and therapeutic approaches that will significantly improve patient survival. Specially, those that involves in progression of disease would be helpful to mechanism research.

METHODS

In the present study, we investigated the distinguishing metabolites in human esophageal cancer tissues (n = 89) and normal esophageal mucosae (n = 26) using a (1)H nuclear magnetic resonance ((1)H-NMR) based assay, which is a highly sensitive and non-destructive method for biomarker identification in biological systems. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) were applied to analyse (1)H-NMR profiling data to identify potential biomarkers.

RESULTS

The constructed OPLS-DA model achieved an excellent separation of the esophageal cancer tissues and normal mucosae. Excellent separation was obtained between the different stages of esophageal cancer tissues (stage II = 28; stage III = 45 and stage IV = 16) and normal mucosae. A total of 45 metabolites were identified, and 12 of them were closely correlated with the stage of esophageal cancer. The downregulation of glucose, AMP and NAD, upregulation of formate indicated the large energy requirement due to accelerated cell proliferation in esophageal cancer. The increases in acetate, short-chain fatty acid and GABA in esophageal cancer tissue revealed the activation of fatty acids metabolism, which could satisfy the need for cellular membrane formation. Other modified metabolites were involved in choline metabolic pathway, including creatinine, creatine, DMG, DMA and TMA. These 12 metabolites, which are involved in energy, fatty acids and choline metabolism, may be associated with the progression of human esophageal cancer.

CONCLUSION

Our findings firstly identify the distinguishing metabolites in different stages of esophageal cancer tissues, indicating the attribution of metabolites disturbance to the progression of esophageal cancer. The potential biomarkers provide a promising molecular diagnostic approach for clinical diagnosis of human esophageal cancer and a new direction for the mechanism study.

Clinicopathologic features and treatment outcomes of patients with human epidermal growth factor receptor 2-positive adenocarcinoma of the esophagus and gastroesophageal junction

Human epidermal growth factor receptor 2 (HER2) is overexpressed in 21% of gastric and 33% of gastroesophageal junction (GEJ) adenocarcinomas. Trastuzumab has been approved for metastatic HER2-positive gastric/GEJ cancer in combination with chemotherapy. This retrospective analysis was undertaken to better define the clinicopathologic features, treatment outcomes, and prognosis in patients with HER2-positive adenocarcinoma of the esophagus/GEJ. Pathologic specimens from 156 patients with adenocarcinoma of the esophagus/GEJ treated on clinical trials with chemoradiation and surgery were tested for HER2. Seventy-six patients also received 2 years of gefitinib. Baseline characteristics and treatment outcomes of the HER2-positive and negative patients were compared both in aggregate and separately for each of the two trials. Of 156 patients, 135 had sufficient pathologic material available for HER2 assessment. HER2 positivity was found in 23%; 28% with GEJ primaries and 15% with esophageal primaries (P= 0.10). There was no statistical difference in clinicopathologic features between HER2-positive and negative patients except HER2-negative tumors were more likely to be poorly differentiated (P < 0.001). Locoregional recurrence, distant metastatic recurrence, any recurrence, and overall survival were also statistically similar between the HER2-positive and the HER2-negative groups, in both the entire cohort and in the gefitinib-treated subset. Except for tumor differentiation, HER2-positive and negative patients with adenocarcinoma of the esophagus and GEJ do not differ in clinicopathologic characteristics and treatment outcomes. Given the demonstrated benefit of trastuzumab in HER2-positive gastric cancer and the similar incidence of HER2 overexpression in esophageal/GEJ adenocarcinoma, further evaluation of HER2-directed therapy in this disease seems indicated.

Definitive chemoradiotherapy for esophageal carcinoma

Radiation therapy plays an important role in the treatment of esophageal cancer. Radiation therapy may be combined with chemotherapy, used as a component of induction therapy, used in the adjuvant setting, or used for palliation of advanced disease. Chemotherapy is also occasionally used as a solitary treatment modality for patients with esophageal cancer. Current treatment protocols include multiple agents, and agents directed against specific molecular targets have been investigated in clinical trials. This article discusses future directions related to the selection of radiation treatment protocols, novel targeted chemotherapeutic agents, and the selection of patients for surgery.

Molecular Pathology of Gastrointestinal Cancer

The purpose of this review is to discuss important molecular changes that aid decision making in patient management and play a role in emerging treatment strategies for gastrointestinal malignancies. Although screening and surveillance practices have had an impact on the natural history of some tumor types, gastric carcinoma is a major cause of morbidity and mortality in high prevalence regions and colorectal carcinoma is still the fourth leading cause of cancer related death in the United States.

Esophageal cancer metabolite biomarkers detected by LC-MS and NMR methods

Background

Esophageal adenocarcinoma (EAC) is a rarely curable disease and is rapidly rising worldwide in incidence. Barret's esophagus (BE) and high-grade dysplasia (HGD) are considered major risk factors for invasive adenocarcinoma. In the current study, unbiased global metabolic profiling methods were applied to serum samples from patients with EAC, BE and HGD, and healthy individuals, in order to identify metabolite based biomarkers associated with the early stages of EAC with the goal of improving prognostication.

Methodology/Principal Findings

Serum metabolite profiles from patients with EAC (n = 67), BE (n = 3), HGD (n = 9) and healthy volunteers (n = 34) were obtained using high performance liquid chromatography-mass spectrometry (LC-MS) methods. Twelve metabolites differed significantly (p<0.05) between EAC patients and healthy controls. A partial least-squares discriminant analysis (PLS-DA) model had good accuracy with the area under the receiver operative characteristic curve (AUROC) of 0.82. However, when the results of LC-MS were combined with 8 metabolites detected by nuclear magnetic resonance (NMR) in a previous study, the combination of NMR and MS detected metabolites provided a much superior performance, with AUROC = 0.95. Further, mean values of 12 of these metabolites varied consistently from healthy controls to the high-risk individuals (BE and HGD patients) and EAC subjects. Altered metabolic pathways including a number of amino acid pathways and energy metabolism were identified based on altered levels of numerous metabolites.

Conclusions/Significance

Metabolic profiles derived from the combination of LC-MS and NMR methods readily distinguish EAC patients and potentially promise important routes to understanding the carcinogenesis and detecting the cancer. Differences in the metabolic profiles between high-risk individuals and the EAC indicate the possibility of identifying the patients at risk much earlier to the development of the cancer.

The status of phosphorylated p38 in esophageal squamous cell carcinoma

The p38 mitogen-activated protein kinase (MAPK) is a member of the MAPK family, which is initially found to be activated by stress stimuli, proinflammatory cytokines, and growth factors. However, its role in the pathogenesis of esophageal squamous cell carcinoma (ESCC) is largely unkown, so we investigate the role of phosphorylated p38 (p-p38) MAPK in ESCC. First of all, in vitro cell line ECa109, SB203580 as selective inhibitor of p38, can suppress the growth of esophageal cancer cell in a dose- and time-dependent way, suggesting that ECa109 cell growth and proliferation was closely associated with p-p38. Using western-blot analysis of fresh 16 paired surgically resected ESCC and matched non-tumor adjacent tissues (NAT), we showed that p-p38 was significantly expressed higher in NAT compared to ESCC. Moreover, expressions of p-p38 were further confirmed by 162 paired of formalin-fixed paraffin-embedded (FFPE) ESCC and NAT by immunohistochemistry, the same trend result was obtained through statistical analysis that there was increased expression of p-p38 in NAT as compared with ESCC (P < 0.01), and expression of p-p38 was not significantly associated with lymph nodes metastasis (P > 0.05) and ESCC differentiation degree (P > 0.05). Taken together, all the results we obtained demonstrated that p-p38 plays a key role in the malignant transformation of ESCC.

A phase II trial of gefitinib for recurrent or metastatic cancer of the esophagus or gastroesophageal junction

BACKGROUND

Conventional chemotherapeutic agents are of limited benefit in patients with recurrent or metastatic cancer of the esophagus or gastroesophageal junction (GEJ). We report results from a phase II trial in this population using gefitinib, an oral epidermal growth factor receptor inhibitor.

PATIENTS AND METHODS

Eligibility required a diagnosis of esophageal or GEJ adenocarcinoma or squamous cell carcinoma, which was either metastatic or recurrent and incurable after initial therapy. No more than one prior chemotherapy regimen was permitted. Treatment consisted of gefitinib 250 mg daily for a minimum of 8 weeks.

RESULTS

Between April 2003 and January 2010, 58 patients, including 18 who were chemotherapy-naïve, were entered into this trial. Toxicity was modest, although most experienced grade 1-2 diarrhea and/or skin rash. There were 4 partial responders (7%) and 10 patients with stable disease (17%). The clinical benefit (partial response and stable disease) lasted for a median 6.1 months. Median survival for all patients was 5.5 months with survival projections at 1-year of 24.6% and at 2-years of 12.5%.

CONCLUSION

Gefitinib was well tolerated but of limited efficacy in patients with recurrent or metastatic esophageal or GEJ cancer. Further study of this or similar agents will require better patient selection.

Her-2/neu testing and therapy in gastroesophageal adenocarcinoma

Despite ongoing advances in the treatment of gastroesophageal cancer, prognosis remains poor. The best promise to improve this poor survival is provided by new targeted agents. Of these, human epidermal growth factor receptor 2 (HER2) is currently in the spotlight. In this review, we provide an overview of recent developments in HER2 testing and results of clinical trials targeting HER2 in gastroesophageal adenocarcinoma. Based on the encouraging ToGA trial findings it is now expected that routine HER2 testing will be included in the diagnostic work-up of patients with advanced gastric cancer. With regard to this testing, overexpression of the HER2 protein seems to possess the best predictive properties. However, HER2 immunohistochemistry (IHC) is subject to assay and interobserver variability, so standardization and internal and external proficiency testing is an absolute prerequisite, especially as the IHC scoring system in gastric cancer is different from that of breast cancer. Further study is needed to investigate the clinical meaning of the significant heterogeneity observed in both gene amplification and protein overexpression in gastroesophageal cancer. Highly effective therapies for gastroesophageal cancer can only be accomplished by a multi-targeted approach, considering crosstalk between pathways and continuing to optimize chemotherapy.

Tolfenamic acid inhibits esophageal cancer through repression of specificity proteins and c-Met

The non-steroidal anti-inflammatory drug tolfenamic acid (TA) inhibits proliferation of SEG-1 and BIC-1 esophageal cancer cells with half-maximal growth inhibitory concentration values of 36 and 48 muM, respectively. TA also increased Annexin V staining in both cell lines, indicative of proapoptotic activity. Treatment of SEG-1 and BIC-1 cells with TA for up to 72 h decreased expression of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 and this was accompanied by decreased expression of the well-characterized Sp-regulated genes cyclin D1, vascular endothelial growth factor and survivin. TA also decreased hepatocyte growth factor receptor, (c-Met), a receptor tyrosine kinase that is overexpressed in esophageal cancer cells and tumors and is an important drug target. Knockdown of Sp1, Sp3 and Sp4 by RNA interference in SEG-1 and BIC-1 cells also decreased c-Met expression, demonstrating that c-Met is an Sp-regulated gene in esophageal cancer cells. Sp1 was overexpressed in esophageal cancer cells and tumors and increased Sp1 staining was observed in esophageal tumors from patients. TA (20 mg/kg/day) also decreased tumor growth and weight in athymic nude mice bearing SEG-1 cells as xenografts and this was accompanied by increased apoptosis and decreased Sp1 and c-Met staining in tumors from treated mice. Thus, TA-dependent downregulation of Sp transcription factors and c-Met defines a novel chemotherapeutic approach for treatment of esophageal cancer.

Esophageal cancer: current and emerging therapy modalities

During the last few years, there has been a gradual increase in treatment options for patients with esophageal malignancies. Several clinical studies have been performed, covering not only radiation and chemotherapy, but also the introduction of novel biological agents into the treatment arsenal. Patients with esophageal carcinoma are now offered second-line and sometimes even third-line treatments, and the number of research protocols is increasing. Despite the newly awakened interest in this malignancy, the overall 5-year survival rate has remained at approximately 10% since the 1980s. This review contains a compilation of available studies of esophageal malignancies and discusses current treatment options as well as newly developed therapies targeted at growth factor receptors.

Cancer of the esophagus and stomach

Upper gastrointestinal tumors involving the esophagus and the stomach are a serious public health problem worldwide. The West has seen a dramatic increase in the incidence of gastroesophageal cancers in the past 2 decades. Although Barrett esophagus has been well characterized, the exact pathway to developing frank malignancy remains undefined. Current treatments for locoregional disease include surgery, chemotherapy, radiation therapy, or some combination thereof. Clinical trials are currently investigating biologic agents that target signaling pathways in carcinogenesis. Whether this research translates into an improved therapeutic index remains to be seen. This review provides a comprehensive update to physicians and residents who contribute to the care of these patients. Studies in the English language were identified searching PubMed (January 1, 1980, through February 29, 2008) using the terms esophagus, gastric, carcinoma, adenocarcinoma, squamous cell, radiation, chemotherapy, surgery, esophagectomy, and targeted therapy.