Antiangiogenic Therapy in Gastroesophageal Cancer

Co-targeting CD47 and VEGF elicited potent anti-tumor effects in gastric cancer

BACKGROUND

CD47, serving as an intrinsic immune checkpoint, has demonstrated efficacy as an anti-tumor target in hematologic malignancies. Nevertheless, the clinical relevance of CD47 in gastric cancer and its potential as a therapeutic target remains unclear.

METHODS

The expression of CD47 in clinical gastric cancer tissues was assessed using immunohistochemistry and Western blot. Patient-derived cells were obtained from gastric cancer tissues and co-cultured with macrophages derived from human peripheral blood mononuclear cells. Flow cytometry analyses were employed to evaluate the rate of phagocytosis. Humanized patient-derived xenografts (Hu-PDXs) models were established to assess the efficacy of anti-CD47 immunotherapy or the combination of anti-CD47 and anti-VEGF therapy in treating gastric cancer. The infiltrated immune cells in the xenograft were analyzed by immunohistochemistry.

RESULTS

In this study, we have substantiated the high expression of CD47 in gastric cancer tissues, establishing a strong association with unfavorable prognosis. Through the utilization of SIRPα-Fc to target CD47, we have effectively enhanced macrophage phagocytosis of PDCs in vitro and impeded the growth of Hu-PDXs. It is noteworthy that anti-CD47 immunotherapy has been observed to sustain tumor angiogenic vasculature, with a positive correlation between the expression of VEGF and CD47 in gastric cancer. Furthermore, the successful implementation of anti-angiogenic treatment has further augmented the anti-tumor efficacy of anti-CD47 therapy. In addition, the potent suppression of tumor growth, prevention of cancer recurrence after surgery, and significant prolongation of overall survival in Hu-PDX models can be achieved through the simultaneous targeting of CD47 and VEGF using the bispecific fusion protein SIRPα-VEGFR1 or by combining the two single-targeted agents.

CONCLUSIONS

Our preclinical studies collectively offer substantiation that CD47 holds promise as a prospective target for gastric cancer, while also highlighting the potential of anti-angiogenic therapy to enhance tumor responsiveness to anti-CD47 immunotherapy.

First Report of Dramatic Tumor Responses with Ramucirumab and Paclitaxel After Progression on Pembrolizumab in Two Cases of Metastatic Gastroesophageal Adenocarcinoma

Checkpoint inhibitors targeted at programmed cell death-1 receptor (PD-1) and its ligand (PD-L1) can result in significant benefit to a small proportion of patients with cancer, including those with tumors of the stomach and gastroesophageal junction. These drugs are now approved for several solid tumors, including the recent accelerated approval of pembrolizumab for gastroesophageal adenocarcinomas in the third-line setting and beyond based on the KEYNOTE-059 phase II trial. Data are lacking on the efficacy of chemotherapy after progression on PD-1 blockade in metastatic gastroesophageal adenocarcinoma. This report describes the exceptional response of two patients who received ramucirumab plus paclitaxel after progressive disease on pembrolizumab. This early clinical observation suggests that the sequence of administration of PD-1 blockade and chemotherapy may be important in this disease.

VEGFA and VEGFR2 RNAscope determination in gastric cancer

Gastric cancer is the fifth most common cancer and third leading cause of cancer-related death worldwide. Several studies on angiogenic blocking agents in gastric cancer revealing promising results by the use of monoclonal antibodies against VEGFA or its receptor VEGFR2 or against VEGFA activating pathway. The validation of biomarkers useful to better organize the clinical trials involving anti-angiogenic therapies is crucial. Molecular markers such as RNA are increasingly used for cancer diagnosis, prognosis, and therapy guidance as in the case of the targeted therapies concerning the inhibition of angiogenesis. The aim of this study is to set the conditions for evaluating the expression of VEGFA and VEGFR2 in gastric cancer specimens and in healthy gastric mucosa by the use of RNAscope, a novel RNA in situ hybridization (ISH) method that allows the visualization of a specific gene expression in individual cells. We found the increased expression of VEGFA in the tubular glands and VEGFR2 in the endothelium of gastric cancer samples mainly in the T2, T3 and T4 stages of tumor progression as compared to the healthy controls. These results obtained by the application of this highly sensitive method for oligonucleotide detection the role of angiogenesis in gastric cancer progression already highlighted by conventional immunohistochemical methods, and offer significant promise as a new platform for developing and implementing RNA-based molecular diagnostics also in the conditions in which immunohistochemistry is not applicable.

Fatal hemoptysis in patients with advanced esophageal cancer treated with apatinib

Targeted therapy is commonly used for treating advanced malignant tumors. Compared with cytotoxic drugs, targeted drugs have the characteristics of good curative results, less adverse effects, and convenient oral administration. Hence, they are especially suitable for patients with cancer who are not able to tolerate chemotherapy. Anti-angiogenic therapy can achieve the objective by inhibiting the formation of new blood vessels in tumors. Apatinib is a novel tyrosine kinase inhibitor targeting the intracellular domain of vascular endothelial growth factor receptor-2. It has been proven to be effective and safe in treating patients with gastric carcinoma and gastroesophageal junction carcinoma. So far, no reports are available on the treatment of esophageal cancer with apatinib. Two patients with advanced esophageal cancer were treated with oral apatinib because of their poor physical condition. After treatment, the dyspnea symptoms disappeared and quality of life significantly improved. Chest computed tomography showed massive necrosis of tumor tissues in each patient. The tumors significantly reduced and a cavity was formed locally in each patient. However, both patients died of massive hemoptysis, probably due to the rupture of the bronchial artery eroded by tumors. The results indicated that apatinib was effective in treating some patients with advanced esophageal cancer, and adverse effects were controllable. However, doctors should choose appropriate candidates according to apatinib’s indications. In addition, the use of apatinib should be carefully controlled for patients with esophageal cancer, especially in those with large vessels and trachea or bronchus eroded by tumor, so as to avoid or reduce the occurrence of fatal hemorrhage.

Expression of VEGF and Cox-2 in Patients with Esophageal Squamous Cell Carcinoma

Esophageal cancer is a highly aggressive neoplasm. In Brazil, it is the sixth most frequent among men and fifteenth among women. The most common type is squamous cell carcinoma (SCC), responsible for 96% of cases. Twenty-eight specimens of Esophael squamous cell carcinoma (ESCC) were obtained by surgery procedures.The tissues were fixed in formalin and embedded in paraffin. In each case, all available hematoxylin and eosin stained sections were examined and a representative block was selected. The ages of these patients ranged from 40 to 93 years, with a mean age of 60 years. Results: The histological grade of tumors was 4 well-differentiated, 19 moderately differentiated and 5 poorly differentiated. Expression of Cox-2 and VEGF in ESCC was demonstrated in 23 (82,14%) and 13 (44,43%) cases, respectively. Adjacent normal mucosa was positive in 11 (39,29%) samples and 9 (32,15%) samples for Cox-2 and VEGF, respectively. No relationship between the expression of Cox-2 and VEGF with the clinicopathological parameters, including gender, age, surgical margin, lymph node status and tumor differentiation. The median follow-up period was 60 months. Survival analysis of patients with ESCC showed no relationship with the expression of Cox-2 and VEGF. Conclusion: VEGF and Cox-2 are expressed in ESCC. Cox-2, VEGF, play a significant role in the origin and development of ESCC and the inhibitors of these proteins could prove to be an important therapeutic tool in the control of this disease.

Angiogenesis and Anti-Angiogenic Therapy in Gastric Cancer

Gastric cancer is one of the most frequent malignancies worldwide. Despite improvements in diagnosis and therapy, the overall prognosis remains poor. In the last decade, several anti-angiogenic drugs for cancer treatment have been approved and lately also introduced to gastric cancer treatment. While the initial trials focused only on unresectable or metastatic cancer, anti-angiogenic treatment is now also investigated in the perioperative and neoadjuvant setting. In this review, an overview of the role of angiogenesis and angiogenic factors in gastric cancer as well as anti-angiogenic treatment of gastric cancer is provided. Findings from in vitro and animal studies are summarized and put in a context with translational data on angiogenesis in gastric cancer. The most important angiogenic factors and their effect in gastric cancer are highlighted and clinical trials including anti-angiogenic drugs are discussed. Finally, an outlook of biomarkers for predicting response to anti-angiogenic treatment is presented, the ongoing trials on this topic are discussed and current challenges of anti-angiogenic therapy are outlined.

Probe-based confocal laser endomicroscopy for in vivo evaluation of the tumor vasculature in gastric and rectal carcinomas

Probe-based Confocal Laser Endomicroscopy (pCLE) is a powerful imaging technique that allows to perform gastrointestinal endomicroscopy at subcellular resolution. The aim of this study was to assess the use of pCLE to evaluate tumor angiogenesis in rectal and gastric cancers. A total of 35 consecutive patients with gastric and 91 with rectal carcinomas underwent endoscopy and pCLE during the same examination. Vascular assessment was based on vessel shape and size, vessel permeability and blood flow, and allowed the creation of an angiogenic score ranging from 0, for normal vasculature, to 4, for aberrant vasculature. A significant difference for the presence of vessels with large diameter and defective blood flow was found between rectal and gastric cancers. Overall, rectal cancers displayed a higher angiogenic score compared to gastric cancers. Conventional therapy induced a striking reduction in the angiogenic score only in rectal cancer patients. Taken together, our findings suggest that the pCLE technology is suitable for the evaluation of the tumor microvasculature abnormalities. Therefore, the real-time assessment of the vasculature status may represent a promising approach to predict the efficacy of the treatments and improve the clinical management of patients with gastric or rectal carcinomas.