Metastatic gastric cancer - focus on targeted therapies

Combined Vaccination with B Cell Peptides Targeting Her-2/neu and Immune Checkpoints as Emerging Treatment Option in Cancer

The application of monoclonal antibodies (mAbs), targeting tumor-associated (TAAs) or tumor-specific antigens or immune checkpoints (ICs), has shown tremendous success in cancer therapy. However, the application of mAbs suffers from a series of limitations, including the necessity of frequent administration, the limited duration of clinical response and the emergence of frequently pronounced immune-related adverse events. However, the introduction of mAbs has also resulted in a multitude of novel developments for the treatment of cancers, including vaccinations against various tumor cell-associated epitopes. Here, we reviewed recent clinical trials involving combination therapies with mAbs targeting the PD-1/PD-L1 axis and Her-2/neu, which was chosen as a paradigm for a clinically highly relevant TAA. Our recent findings from murine immunizations against the PD-1 pathway and Her-2/neu with peptides representing the mimotopes/B cell peptides of therapeutic antibodies targeting these molecules are an important focus of the present review. Moreover, concerns regarding the safety of vaccination approaches targeting PD-1, in the context of the continuing immune response, as a result of induced immunological memory, are also addressed. Hence, we describe a new frontier of cancer treatment by active immunization using combined mimotopes/B cell peptides aimed at various targets relevant to cancer biology.

Significance of aquaporins' expression in the prognosis of gastric cancer

Gastric carcinoma is one of the most lethal malignancy at present with leading cause of cancer-related deaths worldwide. Aquaporins (AQPs) are a family of small, integral membrane proteins, which have been evidenced to play a crucial role in cell migration and proliferation of different cancer cells including gastric cancers. However, the aberrant expression of specific AQPs and its correlation to detect predictive and prognostic significance in gastric cancer remains elusive. In the present study, we comprehensively explored immunohistochemistry based map of protein expression profiles in normal tissues, cancer and cell lines from publicly available Human Protein Atlas (HPA) database. Moreover, to improve our understanding of general gastric biology and guide to find novel predictive prognostic gastric cancer biomarker, we also retrieved 'The Kaplan-Meier plotter' (KM plotter) online database with specific AQPs mRNA to overall survival (OS) in different clinicopathological features. We revealed that ubiquitous expression of AQPs protein can be effective tools to generate gastric cancer biomarker. Furthermore, high level AQP3, AQP9, and AQP11 mRNA expression were correlated with better OS in all gastric patients, whereas AQP0, AQP1, AQP4, AQP5, AQP6, AQP8, and AQP10 mRNA expression were associated with poor OS. With regard to the clinicopathological features including Laurens classification, clinical stage, human epidermal growth factor receptor 2 (HER2) status, and different treatment strategy, we could illustrate significant role of individual AQP mRNA expression in the prognosis of gastric cancer patients. Thus, our results indicated that AQP's protein and mRNA expression in gastric cancer patients provide effective role to predict prognosis and act as an essential agent to therapeutic strategy.

Clinicopathological factors associated with HER2-positive gastric cancer: A meta-analysis

BACKGROUND

The treatment of patients with advanced gastric cancer remains a most challenging task in the clinical practice. Recently, targeted therapies have significantly impacted the treatment strategy for many common malignancies. The use of trastuzumab, a monoclonal antibody against human epidermal growth factor receptor 2 (HER2; also known as ERBB2), plus chemotherapy proved to improve median overall survival in patients with advanced gastric cancer, compared with chemotherapy alone in Trastuzumab for Gastric Cancer (ToGA) trial. However, the prognostic value of HER2 status in gastric cancer remains controversial. Therefore, the aim of this study was to investigate the clinical pathology significance of HER2 overexpression in resectable gastric cancer for selecting the right patients with gastric cancer who may benefit from trastuzumab treatment.

METHODS

Publications reported the clinicopathological factors associated with HER2 status in gastric cancer from 2012 to 2017 were collected. The literature databases, such as "Cochrane Library", "Sciencedirect", "Springer", "PubMed", "Embase", were extensively searched to retrieve the clinical studies of HER2 expression in gastric cancer. The major outcomes measures were odds ratios (ORs) and their 95% CIs. Statistical analysis was carried out by Revman software 5.3. The Newcastle-Ottawa scale was used to assess the quality of evidence.

RESULT

Fifteen studies met our inclusion criteria. This study demonstrated that the pooled OR for HER2 positivity was associated with being male (OR: 1.42; 95% CI: 1.23-1.64), well/moderately differentiated tumor (OR: 2.76; 95% CI: 1.72-4.45), and for intestinal-type tumor (OR: 0.31; 95% CI: 0.25-0.38). However, it had no correlation with depth of tumor (P = .07), venous invasion (P = .82), and lymphovascular invasion (P = .24).

CONCLUSION

HER2-positive expression was associated with male gender, intestinal type, and well/moderate cell differentiation. We recommend that those gastric cancer patients who may benefit from trastuzumab treatment should be subjected to targeted therapies. However, detecting HER2 status may contribute to the target therapy for gastric carcinoma using trastuzumab. This would be strengthened by further studies incorporating comorbidity data, and outcomes from centralized programs.

Metastatic gastric cancer treatment: Second line and beyond

Advanced gastric cancer (aGC), not amenable to curative surgery, is still a burdensome illness tormenting afflicted patients and their healthcare providers. Whereas combination chemotherapy has been shown to improve survival and tumor related symptoms in the frontline setting, second-line therapy (SLT) is subject to much debate in the scientific community, mainly because of the debilitating effects of GC, which would impede the administration of cytotoxic therapy. Recent data has provided sufficient evidence for the safe use of SLT in patients with an adequate performance status. Taxanes, Irinotecan and even some Fluoropyrimidine analogs were found to provide a survival advantage in this subset of patients. Most importantly, quality of life measures were also improved through the use of adequate therapy. Even more pertinent were the findings involving antiangiogenic agents, which would add measurable improvements without significantly jeopardizing the patients’ well-being. Further lines of therapy are cause for much more debate nowadays, but specific targeted agents have shown considerable promise in this context. We herein review noteworthy published data involving the use of additional lines of the therapy after failure of standard frontline therapies in patients with aGC.

Targeted therapies in gastric cancer treatment: where we are and where we are going

Gastric cancer (GC) is one of the most common malignancies and a major cause of cancer-related deaths worldwide. Its incidence has significantly declined over the last few decades, probably due to the identification of specific etiologic agents such as Helicobacter pylori and other dietary and environmental risk factors. Nevertheless, most of the cases are unfortunately diagnosed at an advanced stage justifying median overall survival rates frequently not exceeding one year. Palliative combination chemotherapy usually represented by a platinum-based doublet is the mainstay of treatment in the metastatic setting. Adding a third drug such as an anthracycline or a taxane has been shown to improve response rate and provide limited survival benefits in fit selected patients. Unlike other tumors, the introduction of molecularly targeted drugs in the medical armamentarium for GC is relatively recent with trastuzumab and ultimately ramucirumab constituting the only agents approved to date. Recent advances in the understanding of GC biology have led to the development of novel targeted therapies holding the promise to further improve treatment outcomes. The aim of this paper is to review the main available data coming from clinical trials of targeted drugs and to describe some of the most interesting molecules in clinical development in GC. These include drugs targeting EGFR, angiogenesis, c-MET, FGFR2, mTOR and immune checkpoints.

Targeted therapy for advanced gastric cancer: A review of current status and future prospects

In the West in particular, the vast majority of gastric cancer (GC) patients present with advanced-stage disease. Although combination chemotherapy is still the most important component of treatment for these patients, it confers a modest survival advantage. Recently, increased knowledge of the key molecular signaling pathways involved in gastric carcinogenesis has led to the discovery of specific molecular-targeted therapeutic agents. Some of these agents such as trastuzumab and ramucirumab have changed the treatment paradigm for this disease. In this paper, we will summarize the current clinical status of targeted drug therapy in the management of GC.

Microarray analysis in gastric cancer: A review

Gastric cancer is one of the most common tumors worldwide. Although several treatment options have been developed, the mortality rate is increasing. Lymph node involvement is considered the most reliable prognostic indicator in gastric cancer. Early diagnosis improves the survival rate of patients and increases the likelihood of successful treatment. The most reliable diagnostic method is endoscopic examination, however, it is expensive and not feasible in poorer countries. Therefore, many innovative techniques have been studied to develop a new non-invasive screening test and to identify specific serum biomarkers. DNA microarray analysis is one of the new technologies able to measure the expression levels of a large number of genes simultaneously. It is possible to define the gene expression profile of the tumor and to correlate it with the prognosis and metastasis formation. Several studies in the literature have been published on the role of microarray analysis in gastric cancer and the mechanisms of proliferation and metastasis formation. The aim of this review is to analyze the importance of microarray analysis and its clinical applications to better define the genetic characteristics of gastric cancer and its possible implications in a more decisive treatment.

Importance of HER2 Work-Up and Treatment Even in Patients with Poor Performance Status: A Case Report

Gastric cancer is one of most common types of cancers. Metastatic gastric cancer has a poor prognosis and is accepted as incurable at this stage. Treatment of metastatic gastric cancer did not progress substantially until new targeted agents have come out. Recently published ToGA trial showed promising results in HER2 overexpressing metastatic gastric cancer. In this case we present a case with an excellent complete response with anti-HER2 treatment. Most importantly, we wanted to emphasize (1) the importance of early determination of HER2 overexpression, and (2) to draw attention of anti-HER2 agents in the first line treatment even in patients with a poor performance status.

Clinical and prognostic significance of HIF-1α, PTEN, CD44v6, and survivin for gastric cancer: a meta-analysis

Purpose

This study was to quantitatively summarize published data for evaluating the clinical and prognostic significance of four proteins involved in hypoxia-inducible factor-1 (HIF-1α) regulation of the metastasis cascade.

Methods

Searches were performed using the MEDLINE, EMBASE, Cochrane Library, and Chinese Biomedicine databases without any language restrictions. Studies were pooled and either the summary risk ratio (RR) or odds ratio (OR) was calculated. Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication bias was also performed.

Results

Seventeen studies evaluated HIF-1α, 20 studies evaluated phosphatase and tensin homolog (PTEN), 20 studies evaluated Survivin, and 16 studies evaluated CD44v6. Our results showed that increased HIF-1α expression was linked to a poor 5-year overall survival (RR = 1.508; 95% confidence interval (CI) 1.318–1.725; P<0.001). Decreased survival was heavily influenced by advanced tumor invasion (OR = 3.050; 95% CI 2.067–4.501; P<0.001), lymph node metastasis (1415 patients; OR = 3.486, 95% CI 2.737–4.440; P<0.001), distant metastasis (OR = 6.635; 95% CI 1.855–23.738; P = 0.004), vascular invasion (OR = 2.368; 95% CI 1.725–3.252; P<0.001), dedifferentiation (OR = 2.112; 95% CI 1.410–3.163; P<0.001), tumor size (OR = 1.921; 95% CI 1.395–2.647; P<0.001), and a higher TNM stage (OR =  2.762; 95% CI 1.941–3.942; P<0.001). Similarly, aberrant expression of PTEN, CD44v6, and Survivin were also observed in tumors that correlated with poor OS. The higher ORs of death at 5 years were 1.637 (95% CI = 1.452–1.845; P<0.001), 1.901 (95% CI = 1.432–2.525; P<0.001), and 1.627 (95% CI = 1.384–1.913; P<0.001), respectively, with an OR>2 for the main stratified meta-analyses of clinical factors.

Conclusions

Our findings indicate that HIF-1α/PTEN/CD44v6/Survivin, as measured by immunohistochemistry, can be used to predict the prognosis and potential for invasion and metastasis in Asian patients with gastric cancer. The development of strategies against this subset of proteins could lead to new therapeutic approaches.

HER2, MET and FGFR2 oncogenic driver alterations define distinct molecular segments for targeted therapies in gastric carcinoma

Background:

Gastric cancer (GC) is a leading cause of cancer deaths worldwide. Since the approval of trastuzumab, targeted therapies are emerging as promising treatment options for the disease. This study aimed to explore the molecular segmentation of several known therapeutics targets, human epidermal growth factor receptor 2 (HER2), MET and fibroblast growth factor receptor 2 (FGFR2), within GC using clinically approved or investigational kits and scoring criteria. Knowledge of how these markers are segmented in the same cohort of GC patients could improve future clinical trial designs.

Methods:

Using immunohistochemistry (IHC) and FISH methods, overexpression and amplification of HER2, FGFR2 and MET were profiled in a cohort of Chinese GC samples. The correlations between anti-tumour sensitivity and the molecular segments of HER2, MET and FGFR2 alterations were further tested in a panel of GC cell lines and the patient-derived GC xenograft (PDGCX) model using the targeted inhibitors.

Results:

Of 172 GC patients, positivity for HER2, MET and FGFR2 alternations was found in 23 (13.4%), 21 (12.2%) and 9 (5.2%) patients, respectively. Positivity for MET was found in 3 of 23 HER2-positive GC patients. Co-positivity for FGFR2 and MET was found in 1 GC patient, and amplification of the two genes was found in different tumour cells. Our study in a panel of GC cell lines showed that in most cell lines, amplification or high expression of a particular molecular marker was mutually exclusive and in vitro sensitivity to the targeted agents lapatinib, PD173074 and crizotinib was only observed in cell lines with the corresponding high expression of the drugs' target protein. SGC031, an MET-positive PDGCX mouse model, responded to crizotinib but not to lapatinib or PD173074.

Conclusions:

Human epidermal growth factor receptor 2, MET and FGFR2 oncogenic driver alterations (gene amplification and overexpression) occur in three largely distinct molecular segments in GC. A significant proportion of HER2-negative patients may potentially benefit from MET- or FGFR2-targeted therapies.

Ten-year follow-up of a prospective trial for the targeted therapy of gastric cancer with the human monoclonal antibody PAT-SC1

The fully human monoclonal antibody PAT-SC1 is specific for an isoform of CD55 (decay-accelerating factor) designated CD55^PAT-SC1. This antigen is expressed in the majority (80%) of gastric cancers (GCs), and the antibody induces tumour cell-specific apoptosis in vitro as well as in vivo. PAT-SC1, therefore, has been deemed promising as a therapeutic agent. Here, we describe the results of an academic clinical study performed in a neoadjuvant setting with resectable GC patients. Patients undergoing treatment for GC between 1997 and 2001 were tested for CD55^PAT-SC1 expression. Fifty-one resectable patients that tested positively received a single administration of 20 mg PAT-SC1 48 h prior to surgery. They underwent standard surgery with either subtotal or total gastrectomy with bursectomy, omentectomy and a modified D2-lymphadenectomy, aimed at R0 resection. Primary endpoints of the present study were to evaluate side-effects of the PAT-SC1 antibody treatment and to evaluate histopathological effects such as tumour regression and induction of apoptosis. Long-term survival was a secondary endpoint. Administration of PAT-SC1 appeared safe with only reversible side-effects according to WHO grade I and II. Despite the low-dose of the antibody, 81.6% of the patients showed signs of increased apoptosis within the primary tumour and 60% showed signs of tumour cell regression. Comparison of the 10-year survival rates of the R0-resected CD55^PAT-SC1-positive patients treated with the PAT-SC1 antibody with a historical collective of R0-resected CD55^PAT-SC1-positive patients not treated with PAT-SC1 indicated a survival benefit in the treated patients. Furthermore, comparison of the patient survival of CD55^PAT-SC1-positive vs. CD55^PAT-SC1-negative groups suggested that CD55^PAT-SC1 antigen expression is an independent predictor of poor survival in a Cox regression analysis. Antibody PAT-SC1 may be a useful additive therapeutic agent in the treatment of patients with CD55^PAT-SC1-expressing GCs. In combination with radical standard surgery, PAT-SC1 given as an adjuvant or neoadjuvant immunotherapeutic agent induces apoptosis in tumour cells which may improve survival of these patients. Because of the human origin and its specific binding to the CD55^PAT-SC1 antigen, PAT-SC1 was well tolerated in this trial.

Effect of Chunyangzhengqi capsules on cell proliferation and apoptosis in human gastric cancer cell line MGC-803

AIM: To observe the effect of Chunyangzhengqi capsules on the growth of gastric cancer MGC-803 cells.

METHODS: MGC-803 cells were treated with Chunyangzhengqi capsules at a concentration of 200, 400, 800 or 1600 μg/mL. Cell morphological changes were observed under an inverted microscope. Cell cycle was examined by flow cytometry (FCM). Apoptosis was analyzed by Hoechest-33258 staining. The spectrometry was used to detect Caspase3 activity.

RESULTS: Chunyangzhengqi capsules inhibited the proliferation of MGC-803 cells in a dose- and time-dependent manner. The IC50 values of Chunyangzhengqi capsules at 24, 48 and 72 h were 1734, 1534 and 1094 μg/mL, respectively. After treatment, cells exhibited apoptosis in morphology. Chunyangzhengqi capsules could induce apoptosis of MGC-803 cells and block cells at S phase. The activity of Caspase3 was significantly increased in cells treated with Chunyangzhengqi capsules at a concentration of 1600 μg/mL for 16 h.

CONCLUSION: Chunyangzhengqi capsules inhibit cell proliferation and induce apoptosis in human gastric cancer cell line MGC-803.

Loss of RUNX3 increases osteopontin expression and promotes cell migration in gastric cancer

Loss of RUNX3 expression is frequently observed in gastric cancer and is highly associated with lymph node metastasis and poor prognosis. However, the underlying molecular mechanisms of gastric cancer remain unknown. In this study, we found that the protein levels of RUNX3 and osteopontin (OPN) are inversely correlated in gastric cancer clinical specimens and cell lines. Furthermore, similar inverse trends between RUNX3 and OPN messenger RNA (mRNA) expression were demonstrated in six out of seven normal-tumor-paired gastric cancer clinical specimens. In addition, low RUNX3 and high OPN expression were associated with poor prognosis in gastric cancer patients. Ectopic expression of green fluorescent protein-RUNX3 reduced OPN protein and mRNA expression in the AGS and SCM-1 gastric cancer cell lines. In contrast, knockdown of RUNX3 in GES-1, a normal gastric epithelial cell line, increased OPN expression. Although three RUNX3-binding sequences have been identified in the OPN promoter region, direct binding of RUNX3 to the specific binding site, -142 to -137bp, was demonstrated by chromatin immunoprecipitation assay. The binding of RUNX3 to the OPN promoter significantly decreased OPN promoter activity. The knockdown of OPN or overexpression of RUNX3 inhibited cell migration in AGS and SCM-1 cells; however, the coexpression of RUNX3 and OPN reversed the RUNX3-reduced migration ability in AGS and SCM-1 cells. In contrast, the knockdown of both RUNX3 and OPN inhibited RUNX3-knockdown-induced migration of GES-1 cells. Together, our data demonstrated that RUNX3 is a transcriptional repressor of OPN and that loss of RUNX3 upregulates OPN, which promotes migration in gastric cancer cells.

Molecular targeted agents for gastric cancer: a step forward towards personalized therapy

Gastric cancer (GC) represents a major cancer burden worldwide, and remains the second leading cause of cancer-related death. Due to its insidious nature, presentation is usually late and often carries a poor prognosis. Despite having improved treatment modalities over the last decade, for most patients only modest improvements have been seen in overall survival. Recent progress in understanding the molecular biology of GC and its signaling pathways, offers the hope of clinically significant promising advances for selected groups of patients. Patients with Her-2 overexpression or amplification have experienced benefit from the integration of monoclonal antibodies such as trastuzumab to the standard chemotherapy. Additionally, drugs targeting angiogenesis (bevacizumab, sorafenib, sunitinib) are under investigation and other targeted agents such as mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors are in preclinical or early clinical development. Patient selection and the development of reliable biomarkers to accurately select patients most likely to benefit from these tailored therapies is now key. Future trials should focus on these advances to optimize the treatment for GC patients. This article will review recent progress and current status of targeted agents in GC.

Prognosis significance of HER-2/neu overexpression/amplification in Chinese patients with curatively resected gastric cancer after the ToGA clinical trial

Background

HER-2/neu-targeted therapy has been successfully used in advanced gastric cancer, but the role of HER-2/neu in the prognosis of gastric cancer is not yet clear. In this study, we investigated the correlation between HER-2/neu expression and amplification as well as their association with clinic outcomes in patients with curatively resected gastric cancer.

Methods

We constructed tissue microarray blocks containing >70% of gastric cancer tissue and matched adjacent normal gastric tissue for 227 patients. Expression of the HER-2/neu protein in these specimens was analyzed using immunohistochemical staining. Amplification of HER-2/neu was also analyzed for the same samples using fluorescence in situ hybridization. Data on clinicopathological features and relevant prognostic factors in these patients were analyzed.

Results

Of the 227 gastric cancer samples, 11.89% were positive for HER-2/neu overexpression/amplification under the new scoring system. HER-2/neu overexpression/amplification was closely correlated to the Lauren type, degree of differentiation, tumor size and lymph node metastasis. HER-2/neu overexpression/amplification predicted poor survival in univariate analysis but not in a Cox proportional hazards model.

Conclusion

HER-2/neu overexpression/amplification was not an independent predictor for survival in patients with curatively resected gastric cancer.

Advanced gastric cancer: is there enough evidence to call second-line therapy standard?

Gastric cancer and cancer of the gastro-oesophageal junction (GOJ) are the 4th most common cancer diagnoses worldwide with regional differences in incidence rates. The treatment of gastric and GOJ cancers is complex and requires multimodality treatment including chemotherapy treatment, surgery, and radiotherapy. During the past decade considerable improvements were achieved by advanced surgical techniques, tailored chemotherapies/radiotherapy and technical innovations in clinical diagnostics. In patients with advanced or metastatic gastric/GOJ cancer systemic chemotherapy with fluoropyrimidine/platinum-based regimens (+/-human epidermal growth factor receptor-2 antibody) is the mainstay of treatment. Despite these improvements, the clinical outcome for patients with advanced or metastatic disease is generally poor with 5-year survival rates ranging between 5%-15%. These poor survival rates may to some extent be related that standard therapies beyond first-line therapies have never been defined. Considering that this patient population is often not fit enough to receive further treatments there is an increasing body of evidence from phase-2 studies that in fact second-line therapies may have a positive impact in terms of overall survival. Moreover two recently published phase-3 studies support the use of second-line chemotherapy. A South Korean study compared either, irinotecan or docetaxel with best supportive care and a German study compared irinotecan with best supportive care-both studies met their primary endpoint overall survival. In this "Field of Vision" article, we review these recently published phase-3 studies and put them into the context of clinical prognostic factors helping to guide treatment decisions in patients who most likely benefit.