Molecular targeting therapy using bevacizumab for peritoneal metastasis from gastric cancer

Hypoxia-autophagy axis induces VEGFA by peritoneal mesothelial cells to promote gastric cancer peritoneal metastasis through an integrin α5-fibronectin pathway

BACKGROUND

Peritoneal metastasis (PM) is an important pathological process in the progression of gastric cancer (GC). The metastatic potential of tumor and stromal cells is governed by hypoxia, which is a key molecular feature of the tumor microenvironment. Mesothelial cells also participate in this complex and dynamic process. However, the molecular mechanisms underlying the hypoxia-driven mesothelial-tumor interactions that promote peritoneal metastasis of GC remain unclear.

METHODS

We determined the hypoxic microenvironment in PM of nude mice by immunohistochemical analysis and screened VEGFA by human growth factor array kit. The crosstalk mediated by VEGFA between peritoneal mesothelial cells (PMCs) and GC cells was determined in GC cells incubated with conditioned medium prepared from hypoxia-treated PMCs. The association between VEGFR1 and integrin α5 and fibronectin in GC cells was enriched using Gene Set Enrichment Analysis and KEGG pathway enrichment analysis. In vitro and xenograft mouse models were used to evaluate the impact of VEGFA/VEGFR1 on gastric cancer peritoneal metastasis. Confocal microscopy and immunoprecipitation were performed to determine the effect of hypoxia-induced autophagy.

RESULTS

Here we report that in the PMCs of the hypoxic microenvironment, SIRT1 is degraded via the autophagic lysosomal pathway, leading to increased acetylation of HIF-1α and secretion of VEGFA. Under hypoxic conditions, VEGFA derived from PMCs acts on VEGFR1 of GC cells, resulting in p-ERK/p-JNK pathway activation, increased integrin α5 and fibronectin expression, and promotion of PM.

CONCLUSIONS

Our findings have elucidated the mechanisms by which PMCs promote PM in GC in hypoxic environments. This study also provides a theoretical basis for considering autophagic pathways or VEGFA as potential therapeutic targets to treat PM in GC.

Anti-cancer activity of benzoxazinone derivatives via targeting c-Myc G-quadruplex structure

AIMS

This study aimed to analyze the impact of four synthesized benzoxazinone derivatives as screening drugs on c-Myc-overexpressed cancer cells (H7402, HeLa, SK-RC-42, SGC7901, and A549) and to explore their interaction mechanisms in detail.

MATERIALS AND METHODS

Using morphological analysis, real-time cytotoxicity analysis, wound healing assay, reverse transcription PCR, electrophoretic mobility shift assay, and circular dichroism spectroscopy techniques.

KEY FINDINGS

Results revealed that these four compounds could inhibit proliferation of SK-RC-42, SGC7901, and A549 cells in five cancer cell lines to varying degrees and significantly hinder migration. More importantly, the RT-PCR assay showed that the compounds could surprisingly downregulate the expression of c-Myc mRNA in a dose-dependent manner in the five cancer cells, which may be one of the causes of cancer cell proliferation in vitro inhibition. Further EMSA assays demonstrated that at the molecular level of DNA, four compounds can induce the formation of G-quadruplexes (G4-DNAs) in the c-Myc gene promoter. In addition, the CD result of compound 1 clearly indicates that it specifically induces a c-Myc GC-rich 36mer double-stranded DNA in the c-Myc promoter to form a G-quadruplex hybrid configuration. In conclusion, the compounds studied could dose-dependently inhibit the growth and migration of the cancer cells being investigated. This is positively associated with the reduction of overexpression of the c-Myc gene, which may be significantly regulated by the association of compounds with the G-quadruplexes produced in the c-Myc gene promoter region.

SIGNIFICANCE

We conclude that three compounds merit further study, particularly against non-small-cell lung cancer, as leading compounds of anticancer drugs.

Clinical efficacy of concurrent bevacizumab for malignant ascites in nonsquamous cell carcinoma of the lung

PURPOSE

Lung cancer with malignant peritoneal carcinomatosis and malignant ascites is rare, often indicates the terminal stage, and is refractory to treatment. The median survival time of lung cancer patients with malignant ascites has been reported to be as short as 15 days to 2 months in retrospective studies.

METHODS

We reviewed all lung cancer patients who had cytologically or pathologically proven malignant ascites and received aggressive therapy including chemotherapy, anti-angiogenesis agents and target therapy at a Taiwan hospital from January 2015 to December 2017. In addition, we searched PubMed using the terms "lung cancer," "peritoneal carcinomatosis" and "malignant ascites" to find other studies reporting experience of such treatment.

RESULTS

Three consecutive lung cancer patients with malignant ascites (3/265, 1.13%) were included in this case series study, all of whom received bevacizumab with three other drugs (erlotinib, afatinib and gemcitabine). All of the patients showed a good response to treatment with a marked decrease in ascites. Two of the patients had a long progression-free survival time of more than 5 months. In the literature review, several cases reports and case series documented the treatment efficacy, however no prospective or retrospective studies reported treatment strategies.

CONCLUSIONS

Aggressive treatment for lung cancer with malignant ascites is encouraged when possible. Bevacizumab-based treatment may serve as one effective treatment strategy for non-squamous cell lung carcinoma with malignant ascites. Further prospective trials are urgently needed.

Molecular background of the regional lymph node metastasis of gastric cancer

Gastric cancer (GC) is one of the deadliest types of cancer in the world. Lymph node (LN) metastasis is a complex and malignant behavior of GC, involving a sequence of biological processes, including decreased adherence to adjacent cells, extracellular matrix (ECM) degradation and lymphatic channel permeation. LN metastasis is directly associated with the treatment response, local recurrence and long-term survival of patients with GC. Therefore, the molecular mechanisms of LN metastasis in GC development require further investigation. Recently, a large number of clinical studies have focused on the molecular mechanisms and biological markers of tumor invasion and metastasis. However, few articles have broadly summarized LN metastasis in GC, and the molecular mechanisms of LN metastasis are not yet fully understood. In the present review, the molecular mechanisms of LN metastasis in GC will be discussed, including the following aspects: Cell adhesion and movement, ECM degradation, new vessel formation, and molecular pattern differences between metastatic LNs and the primary tumor. This review may lead to a better understanding of LN metastasis in GC, and the identification of new diagnostic markers.

Chemotherapy plus bevacizumab versus chemotherapy plus cetuximab as first-line treatment for patients with metastatic colorectal cancer: Results of a registry-based cohort analysis

The present observational cohort study was designed to elucidate the efficacy and safety profile of bevacizumab or cetuximab with chemotherapy as the first-line treatment in Chinese patients with metastatic colorectal cancer (mCRC). Clinical data were collected from a single-center registry study where mCRC patients received first-line fluoropyrimidine-based chemotherapy combined with either bevacizumab (188 patients with KRAS wild-type or mutated tumors) or cetuximab (101 patients with KRAS wild-type tumors) between January 2009 and December 2013. The Kaplan-Meier method was used for survival analysis. Cox proportional hazards model was used for estimating the prognostic and predictive values of clinicopathological characteristics. No statistically significant difference was observed between the bevacizumab and cetuximab groups in terms of median progression-free survival (PFS) (10.6 vs 8.7 months, P = 0.317), median overall survival (OS) (27.7 vs 28.3 months, P = 0.525), or overall response rate (43.1% vs 53.5%, P = 0.108). For the subset of patients with peritoneal dissemination, bevacizumab-based triplet appears to be superior to cetuximab-based triplet as measured by PFS (9.6 vs 6.1 months) and OS (26.3 vs 12.7 months), but not for patients without peritoneal dissemination (PFS, 10.6 vs 9.1 months; OS, 27.9 vs 30.7 months) (all unadjusted and adjusted interaction P < 0.05). Our study suggests that bevacizumab- or cetuximab-based regimens have similar effectiveness as first-line treatment of mCRC in Chinese population. Patients with peritoneal dissemination were likely to gain more benefit from bevacizumab than cetuximab treatment. Future prospective studies are required to further confirm these results.

Exploring the role of molecular biomarkers as a potential weapon against gastric cancer: A review of the literature

Gastric cancer (GC) is a global health problem and a major cause of cancer-related death with high recurrence rates ranging from 25% to 40% for GC patients staging II-IV. Unfortunately, while the majority of GC patients usually present with advanced tumor stage; there is still limited evidence-based therapeutic options. Current approach to GC management consists mainly of; endoscopy followed by, gastrectomy and chemotherapy or chemo-radiotherapy. Recent studies in GC have confirmed that it is a heterogeneous disease. Many molecular characterization studies have been performed in GC. Recent discoveries of the molecular pathways underlying the disease have opened the door to more personalized treatment and better predictable outcome. The identification of molecular markers is a useful tool for clinical managementin GC patients, assisting in diagnosis, evaluation of response to treatment and development of novel therapeutic modalities. While chemotherapeutic agents have certain physiological effects on the tumor cells, the prediction of the response is different from one type of tumor to the other. The specificity of molecular biomarkers is a principal feature driving their application in anticancer therapies. Here we are trying to focus on the role of molecular pathways of GC and well-established molecular markers that can guide the therapeutic management.

Diagnosis and treatment of peritoneal metastasis of gastric cancer

As the main reason of death in patients with gastric cancer, peritoneal metastasis is still a major problem to be solved. As we all know, peritoneal metastasis is the main form of advanced gastric cancer and gastric cancer recurrence, which involves a complex, multi-stage, multifactorial pathological process. The diagnosis and treatment of peritoneal metastasis of gastric cancer are particularly difficult. The good news is that through active exploration and clinical research, several important achievements have been made and gradually bring the gospel to clinical patients. This paper will review the recent progress in the diagnosis and treatment of peritoneal metastasis of gastric cancer.

Gastric cancer in young vs old Romanian patients: immunoprofile with emphasis on maspin and mena protein reactivity

Increasing number of early-onset gastric carcinomas (GCs) and controversial results regarding the differences among young and older patients with this type of cancer are the reasons why correlation of clinicopathological factors with molecular markers is necessary. The aim of our study was to compare the demographic, clinical and immunohistochemical (IHC) aspects in Romanian patients with GC diagnosed below and above 45 years old. In 191 samples provided from patients with GC, the clinicopathological parameters were correlated with a panel of 15 antibodies: E-cadherin, HER-2, VEGF, CD31, CD105, COX-2, maspin, bax, bcl-2, p53, Ki67, MLH-1, MSH-2, mena protein and vimentin. Compared to the conventional cases, GCs diagnosed below 45 years old were more frequently located at the gastroesophageal junction and presented a higher percentage of lymph node metastases. The diffuse type E-cadherin/mena/p53/Ki67/bax-negative cases that displayed nuclear maspin positivity were also more frequently in younger patients. The intestinal type early-onset GCs were the most angiogenic ones, the apoptotic rate being lower than in the intestinal type GCs of the aged. Compared to the conventional cases, in the early-onset GCs the nuclear maspin-mediated antiproliferative activity is more intense in diffuse type while the mena-dependent tumor cell proliferation is more characteristic for intestinal type GCs.

Peritoneal tumor carcinomatosis: pharmacological targeting with hyaluronan-based bioconjugates overcomes therapeutic indications of current drugs

Peritoneal carcinomatosis still lacks reliable therapeutic options. We aimed at testing a drug delivery strategy allowing a controlled release of cytotoxic molecules and selective targeting of tumor cells. We comparatively assessed the efficacy of a loco-regional intraperitoneal treatment in immunocompromised mice with bioconjugates formed by chemical linking of paclitaxel or SN-38 to hyaluronan, against three models of peritoneal carcinomatosis derived from human colorectal, gastric and esophageal tumor cell xenografts. In vitro, bioconjugates were selectively internalized through mechanisms largely dependent on interaction with the CD44 receptor and caveolin-mediated endocytosis, which led to accumulation of compounds into lysosomes of tumor cells. Moreover, they inhibited tumor growth comparably to free drugs. In vivo, efficacy of bioconjugates or free drugs against luciferase-transduced tumor cells was assessed by bioluminescence optical imaging, and by recording mice survival. The intraperitoneal administration of bioconjugates in tumor-bearing mice exerted overlapping or improved therapeutic efficacy compared with unconjugated drugs. Overall, drug conjugation to hyaluronan significantly improved the profiles of in vivo tolerability and widened the field of application of existing drugs, over their formal approval or current use. Therefore, this approach can be envisaged as a promising therapeutic strategy for loco-regional treatment of peritoneal carcinomatosis.

Molecular targeting to treat gastric cancer

Trastuzumab that targets human epidermal growth factor receptor 2 (HER2) protein is the only approved molecular targeting agent for treating gastric cancer in Japan and the outcomes have been favorable. However, trastuzumab is effective for only 10% to 20% of the population with gastric cancer that expresses HER2 protein. Molecular targeting therapy with bevacizumab against vascular endothelial growth factors (VEGF) and with cetuximab and panitumumab against the epidermal growth factors pathway that have been approved for treating colorectal cancer are not considered effective for treating gastric cancer according to several clinical trials. However, ramucirumab that targets VEGF receptor-2 prolonged overall survival in a large phase III clinical trial and it might be an effective molecular targeting therapy for gastric cancer. The significance of molecular targeting therapy for gastric cancer remains controversial. A large-scale randomized clinical trial of novel molecular targeting agents with which to treat gastric cancer is needed.