Metastatic gastric cancer treatment: a little slow but worthy progress

A New Method for Early Screening of Gastric Cancer (G17 and CA724 Dual-Labeled Time-Resolved Fluorescence Immunoassay)

Gastric carcinoma (GC) is one of the most common malignancies in the world with the great early screening challenges. The study is aimed at establishing a new detection method for early screening GC using time-resolved fluorescence immunoassay (TRFIA) via quantitative detection of gastrin-17 (G-17) and carbohydrate antigen 724 (CA724) in serum. Time-resolved analyzer measured the fluorescence intensity. The standards of G-17/CA724 were used for drawing the standard curve, which is used to calculate the concentration of G-17 and CA724 in serum sample. The sensitivity for G-17 was 0.54 pg/mL and for CA724 was 0.28 U/mL with a wide-range analyze concentration (0.1-1000) pg/mL or U/mL. The average recoveries ranged from 100.52% to 110.30% for G-17 and 103.02% to 116.00% for CA724. All CVs of the intra- and interassay were below 10% with high specificity. There was a high Pearson coefficient between this TRFIA method and the commercially available kits (Pearson r 0.9117 for G-17 and 0.9449 for CA724). Additionally, the cutoff value was 88.41 pg/mL and 5.47 U/mL for CA724 in health subjects. This study established a TRFIA method for simultaneous detection of the concentrations of G-17 and CA724 in serum, which provide a new method for sensitive, accurate, and specific early screening of gastric cancer.

A 1,10-phenanthroline derivative selectively targeting telomeric G-quadruplex induces cytoprotective autophagy, causing apoptosis of gastric cancer cells

AIMS

This study aimed to evaluate the ability of compound 13d to induce autophagy and to promote apoptosis of tumor cells and its interaction mechanism.

MATERIALS AND METHODS

Using CCK-8 assay, transwell assay, fluorescence resonance energy transfer melting analysis (FRET), transmission electron microscopy, flow cytometry assay, immunofluorescence assay, Western blot analysis, and wound healing assay.

KEY FINDINGS

The results indicated that compound 13d could induce autophagy and apoptosis of gastric cancer cells. Moreover, the findings of CCK-8 assay, colony formation, migration and invasion assay, and wound healing assay revealed that compound 13d would effectively inhibit cell proliferation, migration, and invasion. Its IC₅₀ value is about 2.4 μM against gastric cancer cells, which is similar to positive drug‑platinum. 13d specific induction of telomere G-quadruplex formation was proved in extracellular FRET melting assay, and indirectly affected telomerase activity. G-quadruplex formation promoted cell apoptosis and autophagy. Upon incorporating the autophagy inhibitors 3-MA and HCQ, the expression of the autophagy marker protein LC3 was then checked, suggesting that the compound 13d influences the autophagy flux. Furthermore, knocking down the autophagy-related gene Atg5 to reduce the level of autophagy enhances the anti-tumor activity and increases apoptotic cells' proportion. Mechanistic experiments have shown that blocking the Akt/m-TOR signal pathway plays a crucial role in autophagy and G-quadruplex induced telomere dysfunction. DNA damage is the leading cause of autophagy. Compound 13d combined with autophagy inhibitor can inhibit tumor cells more effectively.

SIGNIFICANCE

Our findings demonstrate that compound 13d as a telomeric G-quadruplex ligand induces Telomere dysfunction, DNA damage response, autophagy, and apoptosis in gastric cancer cells by blocking the Akt/m-TOR signaling pathway.

Treatment Strategies of Gastric Cancer-Molecular Targets for Anti-angiogenic Therapy: a State-of-the-art Review

Purpose

Recent studies have suggested that molecular targets for the anti-angiogenic therapy might constitute a basis for additional therapy in gastric cancer treatment. A vast number of molecules, receptors, pathways, specific interactions, and thus strategies that target gastric cancer angiogenesis specifically have been reported in numerous research articles and clinical trials.

Methods

We conducted a systematic literature review of molecularly targeted treatment strategies in gastric cancer on the following databases—PubMed, Google Scholar, and Scopus—on September 20, 2020. Multiple articles and evaluations were searched for studies reporting newly found and promising molecular anti-angiogenic therapy pathways. Eventually, 39 articles regarding the anti-angiogenic therapy in gastric cancer were included in the final analysis.

Results

As a consequence of the release of the pro-angiogenic molecules from the tumour cells, gastric cancer presents high angiogenic capability. Therefore, potential schemes for future treatment strategies include the decrease of the process ligands as well as the expression of their receptors. Moreover, the increase in the angiogenic inhibitor levels and direct aim for the inner walls of the endothelial cells appear as a promising therapeutic strategy. Beyond that, angiogenesis process inhibition seems to indirectly exaggerate the effects of chemotherapy in the considered patients.

Conclusions

The anti-angiogenic treatment in gastric cancer patients evaluates its significance especially in the early stages of the malignancy. The studies conducted so far show that most of the meaningful angiogenic factors and receptors with the potential molecular pathways should be further evaluated since they could potentially play a substantial role in future therapies.

Mevalonate pathway as a novel target for the treatment of metastatic gastric cancer

Gastric mucosa tumors may present as two distinct major entities: Diffuse and intestinal subtypes. There is no standard treatment for advanced or metastatic gastric cancer. The mevalonate pathway and cholesterol homeostasis are important processes in cancer cells that may be highly relevant in terms of cell growth, survival and metastatic potential. Two model cell lines representing intestinal (NCI-N87) and diffuse (Hs746T) metastatic gastric tumor histological subtypes were treated with different drugs that alter membrane lipid metabolism to determine whether cell proliferation, viability and migration were affected. The results indicated that the cells exhibited significant differences in proliferation when treated with the cholesterol-lowering drug simvastatin, but not with terbinafine, another compound that affects cholesterol synthesis. Only simvastatin affected migration in both cell lines. Reposition studies with mevalonolactone, farnesyl pyrophosphate and geranylgeranyl pyrophosphate in the presence of high and low FBS concentrations indicated that both isoprenoids and cholesterol reversed the antiproliferative effects of simvastatin in gastric cancer cells. The cell lines used in the present study had different sensitivities to several potential anti-neoplastic agents that affect the synthesis of membrane lipids. The diffuse gastric cancer cells were particularly sensitive to simvastatin, suggesting it as an option for combination treatment.

Inhibitory effect of endostar combined with radiotherapy on gastric cancer animal models

BACKGROUND

Inhibitory effect of endostar combined with radiotherapy on gastric cancer (GC) animal models and its effect on transforming growth factor-β1 (TGF-β1) and inter-leukin-10 (IL-10) were evaluated.

METHODS

Forty mice of GC model xenograft tumors were prepared and randomly divided into blank control group, endostar group, radiotherapy group, and endostar combined with radiotherapy group (combination group). From the 14th day, a vernier caliper was used for measuring the long and short diameters of the xenograft tumors. The formula V = ab²/2 was used for calculating the tumor volume and to obtain its average value. Tumor growth curves were plotted to calculate the tumor inhibition rate. The growth of xenograft tumors and the behavioral changes of mice were observed. Enzyme-linked immunosorbent assay (ELISA) was used for detecting the expression levels of IL-10 and TGF-β1.

RESULTS

The tumor growth in the combination group was significantly inhibited, and the tumor volume was the smallest compared with the other groups (p < 0.05). Compared to the blank control group, the tumor inhibition rate was 11.8% in endostar group, 33.0% in radiotherapy group, and 52.1% in combination group (p < 0.01). Endostar combined with radiotherapy had an interaction in decreasing the expression levels of TGF-β1 and IL-10 (F = 4.35 and 5.12, p < 0.05). Leucocyte count was significantly higher in control and combination groups than that in endostar and radiotherapy groups. The body weight of mice in endostar and radiotherapy groups decreased after treatment (p < 0.05). The body weight of mice after treatment in control and combination groups increased, with a statistically significant difference compared to that before treatment (p < 0.05). There was a statistically significant difference among all groups after treatment (F = 198.1, p < 0.01).

CONCLUSIONS

Endostar combined with radiotherapy can inhibit tumor growth and downregulate the expression levels of TGF-β1 and IL-10 through synergistic action.

EIF3B is associated with poor outcomes in gastric cancer patients and promotes cancer progression via the PI3K/AKT/mTOR signaling pathway

Purpose

Eukaryotic translation initiation factor (EIF) plays a vital role in protein synthesis. EIF3B is a core subunit of the EIF3 family, and is overexpressed in many tumors. EIF3B is associated with an unfavorable prognosis, as well as the genesis and development of tumors. However, the potential role of EIF3B in gastric cancer (GC) remains unknown. In the current study, we explored the clinical significance and the possible mechanism of EIF3B in the progression of GC.

Methods

EIF3B expression was analyzed in 78 GC tissue samples through quantitative PCR and in 94 GC tissue samples through immunohistochemistry (IHC) staining. The correlation between EIF3B and clinicopathological features was analyzed in GC tissues. The role of EIF3B in GC progression was investigated through in vitro and in vivo assays.

Results

EIF3B expression was upregulated in GC tissues (73.4%, IHC). High expression of EIF3B was significantly correlated with the depth of tumor invasion, lymph node metastasis and TNM stage (P=0.000, 0.000 and 0.000, respectively). Multivariate analysis indicated that GC patients with high EIF3B expression suffered a poorer 5-year survival. EIF3B promoted GC cell proliferation and was strongly associated with proliferating cell nuclear antigen (PCNA) expression in GC samples (P=0.009). It also enhanced tumor cell migration and invasion, which were affected through epithelial-mesenchymal transition (EMT) and the Stat3 signaling pathway. Knockdown of EIF3B in GC cells suppressed the growth of xenograft tumors and lung metastatic colonization in vivo. Furthermore, gene set enrichment analysis (GSEA) and Western blot results demonstrated that EIF3B activated the PI3K/AKT/mTOR signaling pathway.

Conclusion

Our results suggest that EIF3B plays an oncogenic role in GC progression and serves as an independent prognostic factor for GC patients.

Potential therapeutic effects of curcumin in gastric cancer

Despite recent advancements in understanding of the biology of gastric cancer, treatment of patients with advanced gastric cancer remains a major problem. Among different type of phytochemicals, curcumin, a welltable -known phytochemical, has been shown to be a promising cancer chemopreventive agent. Pharmacokinetics, safety, and efficacy of curcumin have been evaluated in several clinical trials against numerous diseases, and for the treatment of human cancer. In the present review, we have collected in vitro and in vivo investigations and studied the chemosensitizing and anticancer effects of curcumin against the gastric cancer cells. In summary, curcumin has been found to have efficient chemosensitizing effect and also inhibits viability, proliferation, and migration of gastric cancer cells mainly via cell cycle arrest and induction of apoptosis by both mitochondrial-dependent and -independent pathways.

Perilaldehyde activates AMP-activated protein kinase to suppress the growth of gastric cancer via induction of autophagy

BACKGROUND AND AIM

Perillaldehyde (PAH), one of the major oil components in Perilla frutescens, is very critical to health maintenance, for a wide range of human chronic diseases, including cancers. AMP-activated protein kinase (AMPK) has been implicated in the activation of autophagy in distinct tissues. This study was designed to explore whether PAH prevents gastric cancer growth and to investigate the molecular mechanism.

METHODS AND RESULTS

In cultured mouse gastric cancer cell line MFCs and human gastric cancer cell lines GC9811-P, PAH activated AMPK by increasing the Thr172 phosphorylation and activity in a time-/concentration-dependent manner. Furthermore, incubation of MFCs with PAH also increased autophagy as determined by monodansylcadaverine (MDC) staining, which was reversed by AMPK inhibitor compound C. PAH further decreased MFCs cell survival, which was abolished by compound C or autophagy inhibitor 3-Methyladenine (3-MA). In vivo studies indicated that 4-week administration of PAH (100 mg/kg/day) suppressed the growth of gastric cancer and increased the levels of autophagy-related proteins, including beclin-1, LC3-II, cathepsin, caspase-3, p53, and cathepsin in tumors isolated from the xenograft model of gastric cancer in mice. Moreover, these anticancer effects produced by PAH were abolished by coadministration of compound C or 3-MA in vivo.

CONCLUSIONS

PAH increases AMPK phosphorylation and activity to induce gastric cancer cell autophagy to inhibit the growth of gastric cancer. In perspective, therapy of PAH should be applied to treat patients with gastric cancer.

Psoriasin overexpression confers drug resistance to cisplatin by activating ERK in gastric cancer

Psoriasin, a member of the S100 multigenic family, which is aberrantly expressed in a variety of human tumors, is considered as an attractive molecular target for cancer treatment. The present study aimed to characterize the role of psoriasin in gastric cancer (GC), the associated pathways through which it contributes to cancer development and progression, and the effect of psoriasin on cellular response to pre-operative chemotherapy in patients with GC. Expression of psoriasin mRNA and protein were analyzed using quantitative polymerase chain reaction and immunohistochemistry of gastric cancer cohorts, respectively. Gastric cancer cell models with differential expression of psoriasin were generated using stable cell lines that overexpressed psoriasin. The in vitro biological functions of the cells in response to psoriasin overexpression and to chemotherapeutic agents were assessed using various cell-based assays. Psoriasin was overexpressed in patients with advanced GC, and high psoriasin levels led to poor clinical outcomes. Increasing psoriasin expression in GC cell lines promoted cell proliferation, migration and invasion in vitro. Furthermore, psoriasin overexpression caused alterations in the levels of epithelial-mesenchymal transition-associated proteins, and activated the extracellular signal-regulated kinase signaling pathway. Additionally, higher levels of psoriasin expression were significantly associated a lack of response to neoadjuvant chemotherapy in patients with GC. Psoriasin overexpression tended to decrease the sensitivity of GC cells to cisplatin, potentially by inhibiting apoptosis or increasing the S-phase population. Taken together, these results indicate that psoriasin may be a promising therapeutic target for GC treatment, and a potential molecular marker to predict patient response to pre-operative chemotherapy.

Antiproliferative effects of the CDK6 inhibitor PD0332991 and its effect on signaling networks in gastric cancer cells

PD0332991 (palbociclib/Ibrance®) is a cyclin-dependent kinase (CDK)4/6 inhibitor that has recently been approved for the treatment of estrogen receptor‑positive advanced breast cancer. The present study investigated the antiproliferative effects of PD0332991 on gastric cancer (GC) cells and the underlying molecular mechanisms. The activity of PD0332991 was tested in several GC cell lines, including AGS, KATO‑Ⅲ, NCI‑N87 and HS746T. Growth inhibitory activity of PD0332991, alone or in combination with fluorouracil (5‑FU), was measured by MTT assay. The effects of PD0332991 on cell cycle progression were analyzed by flow cytometry and western blotting. Protein pathway array and Ingenuity Pathway Analysis were used to identify signaling pathways that may mediate the antiproliferative effects of PD0332991. PD0332991 inhibited proliferation in a dose‑dependent manner and enhanced the activity of 5‑FU in all GC cell lines tested. Cells treated with PD0332991 exhibited cell cycle arrest in G1 phase of the cell cycle, whereas the number of cells in G2/M phase was decreased. PD0332991 also inhibited CDK6‑specific phosphorylation of retinoblastoma on Ser780, reduced the expression of cyclin D1, and induced expression of p53 and p27. Furthermore, 31 proteins were identified, the expression of which was significantly altered following treatment with PD0332991 in at least three cell lines. Pathway analysis indicated that the altered proteins were frequently associated with cell death, cell cycle and the molecular mechanism of cancer. The results of the present study indicated that PD0332991 may inhibit cell proliferation via modulation of the cell cycle, and may affect numerous oncogenic signaling pathways. Therefore, PD0332991 may be considered effective for the treatment of GC.

The BRAF activated non-coding RNA: A pivotal long non-coding RNA in human malignancies

Long non-coding RNAs (lncRNAs) participate in the complex network of cancer and play an important role in tumourigenesis and progression. BRAF activated non-coding RNA (BANCR), a 4-exon transcript of 693-bp, was first discovered as an oncogenic long non-coding RNA in BRAF^V600E melanomas cells in 2012 and was related to melanoma cell migration. Besides melanoma, increasing evidence has explored the potential role of BANCR in the development and progression of multiple other human malignancies, such as retinoblastoma, lung cancer, gastric cancer etc. since its discovery. The expression pattern of BANCR varies in different types of cancers, either as a tumour suppressor or as an accelerator. Functional BANCR may serve as a promising biomarker for cancer diagnosis as well as prognosis evaluation. BANCR-targeted intervention may also become a valuable novel therapeutic tool against human malignancies. This review summarized the advanced research progresses concerning the expression and role of BANCR in different human malignancies.

Metastatic spread in patients with gastric cancer

Background

The epidemiology of metastatic gastric cancer is unexplored because cancer registries seldom cover metastatic involvement apart from “present or not”. We used a novel approach by utilizing Swedish registers to assess metastatic spread in gastric cancer. To our knowledge, this is the first nationwide description of metastases in gastric cancer.

Results

The most common sites of metastasis were liver (in 48% of metastatic cancer patients), peritoneum (32%), lung (15%), and bone (12%). Metastases to the lung, nervous system, and bone were more frequent in cardia cancer and men, whereas non-cardia cancer more frequently metastasized within the peritoneum. Signet ring adenocarcinomas more frequently metastasized within the peritoneum, bone and ovaries, and less frequently to the lungs and liver compared with generic adenocarcinoma. The liver and the peritoneum were commonly single metastases while lung metastases occurred frequently together with liver metastases. The median survival in metastatic gastric cancer was 3 months, worst among those with bone and liver metastases (2 months).

Methods

A total of 7,559 patients with gastric cancer were identified. Metastatic patterns and survival depending on sex, age, stage, anatomical location (cardia and non-cardia), and histological type were assessed.

Conclusions

The patterns of metastasis differ notably depending on histological type. Cardia cancer exhibits a completely different metastatic behavior than non-cardia cancer. Awareness of the differing patterns may guide in tailored diagnosis of metastases. Survivors from cardia cancer would benefit from increased surveillance of extraperitoneal metastases. Bone metastases should be considered in patients with signet ring adenocarcinoma if symptoms emerge.

Celastrus orbiculatus extracts induce apoptosis and inhibit invasion by targeting the maspin gene in human gastric adenocarcinoma cells

Celastrus orbiculatus Thunb. has been used as a remedy against cancer and inflammatory diseases for thousands of years in China. Maspin is expressed in normal cells and downregulated in prostate tumor cells. The underlying mechanisms between C. orbiculatus extract (COE) and maspin remain unclear. In the present study, 3 target-specific 19–25 nucleotide maspin small interfering RNAs were designed and synthesized to knockdown maspin expression. The effects of COE on MGC-803/maspin⁻ cell proliferation were evaluated by the MTT assay. Apoptosis was measured by flow cytometry. Invasive activity was measured with the Transwell assay and the associated molecular mechanisms were assessed by western blot analysis. The results demonstrated that COE significantly promoted the expression of maspin (P<0.01) to induce apoptosis and inhibit invasion and migration in MGC803 cells. The expression levels of phosphorylated (p)-p38 mitogen-activated protein kinase (MAPK), phospho-extracellular regulated protein kinase (Erk), B cell lymphoma-2-associated X protein and caspase-3 were increased in the MGC-803/maspin⁻ cells in a dose-dependent manner. The Erk, B-cell lymphoma 2, p-Akt, Akt and p-mechanistic target of rapamycin (mTOR) protein in MGC-803/maspin⁻ cells were reduced in a dose-dependent manner. This indicated that COE may inhibit invasion and migration through phosphoinositide 3-kinase/Akt/mTOR and MAPK signaling pathways in MGC-803/maspin⁻ cells. In conclusion, COE has the ability to improve the expression of maspin to induce apoptosis and inhibit invasion and migration in human gastric adenocarcinoma cells.

Long non-coding RNA PVT1: Emerging biomarker in digestive system cancer

The digestive system cancers are leading cause of cancer-related death worldwide, and have high risks of morbidity and mortality. More and more long non-coding RNAs (lncRNAs) have been studied to be abnormally expressed in cancers and play a key role in the process of digestive system tumour progression. Plasmacytoma variant translocation 1 (PVT1) seems fairly novel. Since 1984, PVT1 was identified to be an activator of MYC in mice. Its role in human tumour initiation and progression has long been a subject of interest. The expression of PVT1 is elevated in digestive system cancers and correlates with poor prognosis. In this review, we illustrate the various functions of PVT1 during the different stages in the complex process of digestive system tumours (including oesophageal cancer, gastric cancer, colorectal cancer, hepatocellular carcinoma and pancreatic cancer). The growing evidence shows the involvement of PVT1 in both proliferation and differentiation process in addition to its involvement in epithelial to mesenchymal transition (EMT). These findings lead us to conclude that PVT1 promotes proliferation, survival, invasion, metastasis and drug resistance in digestive system cancer cells. We will also discuss PVT1's potential in diagnosis and treatment target of digestive system cancer. There was a great probability PVT1 could be a novel biomarker in screening tumours, prognosis biomarkers and future targeted therapy to improve the survival rate in cancer patients.

Traditional Chinese medicine Ka-Sai-Ping suppresses the growths of gastric cancers via induction of autophagy

Traditional Chinese medication is increasingly used to treat a wide range of human chronic diseases like cardiovascular diseases and cancers. This study was designed to explore whether ka-sai-ping (KSP), a novel traditional Chinese medicine developed by us, prevents gastric cancer growths and to investigate the underlying mechanism. The xenograft model of mouse gastric cancer was established by injecting MFCs into nude mouse subcutaneously. Cell autophagy was assessed by MDC staining. Lysosome and mitochondria were detected by Lyso-Tracker Red and Mito-Traker Green staining. Incubation of cultured mouse gastric cancer cell line MFCs with KSP for 48 hours, concentration-dependently reduced cell survivals and activated autophagy, which were accompanied with damaged lysosomes and mitochondria. In vivo studies indicated that KSP therapy (20 ml/kg/day) for two weeks suppressed the growth of gastric cancer, increased the protein levels of LC3-II, beclin-1, cathepsin L, bcl-2, p53, and capase-3 in tumor tissues from the xenograft model of mouse gastric cancer. Importantly, all these effects induced by KSP were abolished by co-administration of autophagy inhibitor 3-MA. In conclusion, KSP activates cell autophagy to suppress gastric cancer growths. Clinically, KSP is potentially considered as a medicine to treat patients with gastric cancer.

Palliative gastrectomy is beneficial in selected cases of metastatic gastric cancer

BACKGROUND

Salvage chemotherapy is the mainstay of treatment for metastatic gastric cancer (mGC). This study aimed to clarify the effects of palliative gastrectomy (PG) and identify prognostic factors in mGC patients undergoing PG.

METHODS

This was a retrospective review of 333 mGC patients receiving PG or a non-resection procedure (NR) between 2000 and 2010. Clinicopathological factors affecting the prognosis of these patients were collected prospectively and analyzed.

RESULTS

One hundred and ninety-three patients underwent PG and 140 NR. The clinicopathological characteristics were comparable between the two groups except for metastatic pattern. There were no significant differences in postoperative morbidity and mortality between the two groups. The PG group had a significantly longer median overall survival compared with the NR group (7.7 months vs. 4.9 months). In the PG group, age ≤58 years, preoperative albumin level >3 g/dL, ratio of metastatic to examined lymph nodes ≤0.58, and administration of chemotherapy were independent prognostic factors in multivariate analysis.

CONCLUSIONS

Patients undergoing PG had better outcomes than those undergoing NR. Among the patients undergoing resection, age ≤58 years, a better preoperative nutritional status, less nodal involvement and postoperative chemotherapy independently affected patient survival.

The long noncoding RNA PVT1 functions as a competing endogenous RNA by sponging miR-186 in gastric cancer

BACKGROUND

Recent evidence has highlighted the key regulatory roles of long non-coding RNAs (lncRNAs) in tumor development and progression including gastric cancer (GC).The long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) has been identified as an oncogene in some tumors. However, the potential biological roles and regulatory mechanisms of PVT1 involved in GC remained poorly understood.

METHODS

Quantitative real-time PCR (QRT-PCR) was used to determine the expression of PVT1 and miR-186 in GC tissues. The MTT cell proliferation and transwell invasion assays were used to detect the cell proliferation and invasion abilities. Western-blotting analysis was used to detect the protein expression of PCNA and HIF-1α. To understand the tumorigenic mechanism of PVT1, luciferase reporter assays were performed to evaluate whether the miR-186 was a target of PVT1 in GC cells.

RESULTS

In the current study, we showed that PVT1 expression was markedly upregulated in GC tissues and cell lines, and high expression levels of PVT1 were obviously correlated with advanced tumor stage and lymph node metastasis. Further functional experiments indicated up-regulation of PVT1 promoted the GC cell proliferation and invasion, while down-regulation of PVT1 inhibited cell proliferation and invasion. In addition, PVT1 could directly interact with miR-186 in GC cells and this interaction lead to the inhibition of downstream of HIF-1α expression.

CONCLUSIONS

These results suggested that PVT1 acted as a key role in GC pathogenesis and may serve as a potential therapeutic target for GC.

Maternal embryonic leucine zipper kinase serves as a poor prognosis marker and therapeutic target in gastric cancer

Maternal embryonic leucine zipper kinase (MELK) is upregulated in a variety of human tumors, and is considered an attractive molecular target for cancer treatment. We characterized the expression of MELK in gastric cancer (GC) and measured the effects of reducing MELK mRNA levels and protein activity on GC growth. MELK was frequently overexpressed in primary GCs, and higher MELK levels correlated with worse clinical outcomes. Reducing MELK expression or inhibiting kinase activity resulted in growth inhibition, G2/M arrest, apoptosis and suppression of invasive capability of GC cells in vitro and in vivo. MELK knockdown led to alteration of epithelial mesenchymal transition (EMT)-associated proteins. Furthermore, targeting treatment with OTSSP167 in GC patient-derived xenograft (PDX) models had anticancer effects. Thus, MELK promotes cell growth and invasiveness by inhibiting apoptosis and promoting G2/M transition and EMT in GC. These results suggest that MELK may be a promising target for GC treatment.

Gastric cancer: current and evolving treatment landscape

Gastric (including gastroesophageal junction) cancer is the third leading cause of cancer-related death in the world. In China, an estimated 420,000 patients were diagnosed with gastric cancer in 2011, ranking this malignancy the second most prevalent cancer type and resulting in near 300,000 deaths. The treatment landscape of gastric cancer has evolved in recent years. Although systemic chemotherapy is still the mainstay treatment of metastatic disease, the introduction of agents targeting human epidermal growth factor receptor 2 and vascular endothelial growth factor/vascular endothelia growth factor receptor has brought this disease into the molecular and personalized medicine era. The preliminary yet encouraging clinical efficacy observed with immune checkpoint inhibitors, e.g., anti-programmed cell death protein 1/programmed death-ligand 1, will further shape the treatment landscape for gastric cancer. Molecular characterization of patients will play a critical role in developing new agents, as well as in implementing new treatment options for this disease.

MicroRNA-205 suppresses the invasion and epithelial-mesenchymal transition of human gastric cancer cells

Distant metastasis is the predominant pattern of gastric cancer (GC) recurrence, and is the most common cause of cancer‑associated mortality. Accumulating evidence has suggested that aberrant activation of epithelial‑mesenchymal transition has a crucial role in the genesis, invasion and metastasis of various types of cancer, including GC. Using Cell Counting kit‑8 and Transwell assays, the effects of microRNA (miR)‑205 on the proliferation, migration and invasion of NCI‑H87 GC cells were determined, and the potential underlying mechanisms were explored. The results of the present study demonstrated that miR‑205, which has been reported to function as a tumor suppressor in various types of cancer, significantly suppressed the migration and invasion of GC cells, which may be correlated with its suppressive effects on EMT. Upon transfection with miR‑205, the epithelial marker CDH1 (E‑cadherin) was upregulated, and the mesenchymal markers CDH2 (N‑cadherin) and vimentin were suppressed. Furthermore, zinc‑finger E‑box‑binding homeobox factor‑1 (ZEB1) was identified as a putative target gene of miR‑205 in GC, which may be associated with its suppressive effects. The results of the present study may provide novel diagnostic and therapeutic options for the treatment of human GC.

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.

Overexpression of LIMK1 promotes tumor growth and metastasis in gastric cancer

Gastric cancer is the second-leading cause of cancer death in Asia. Despite improvement of therapies, the outcome in patients remains extremely poor because of metastasis. In the present study, we found that LIMK1 is overexpressed in gastric cancer, and its expression level correlate with tumor size, lymph node metastasis and TNM stage. Knockdown of LIMK1 expression could inhibit cell proliferation, migration and invasion in vitro, as well as suppress the activation of FAK/paxillin pathway. Moreover, knockdown of LIMK1 expression retarded tumor growth and peritoneal ametastasis in vivo. This highlights that LIMK1 might be used as a potential target in the treatment of gastric cancer.

Extracts of Celastrus orbiculatus exhibit anti-proliferative and anti-invasive effects on human gastric adenocarcinoma cells

OBJECTIVE

To assess the effect of Celastrus orbiculatus (COE) on growth, invasion and migration of human gastric cancer MGC-803 cells and to explore the possible mechanism.

METHODS

The effect of COE on cell viability, apoptosis, adhesion, invasion and migration were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometric, cell adhesion and transwell assay, respectively. The activity and expression of matrix metalloproteinase-9 (MMP-9) were determined by gelatin zymography, Western blot and quantitative real-time polymerase chain reaction analysis. Meanwhile, effects of COE on the expression of mitogen-activated protein kinases (MAPKs), serine threonine kinase (Akt), nuclear factor κB (NF-κB) were investigated with Western blot analysis.

RESULTS

COE inhibited proliferation and induced apoptosis of MGC-803 cells in a dose-dependent manner. When treated with low-toxic (below 80 μg/mL) doses of COE, cell adhesion, invasion and migration were markedly suppressed. Furthermore, the gelatinolytic activity and expression of MMP-9 were also remarkably suppressed in a dose-dependent manner. In addition, upstream signaling pathways, including the phosphatidylinositol-3 kinase (PI3K)/Akt and NF-κB, were suppressed by COE. Additionally, the PI3K/Akt inhibitor, LY294002, in treating MGC-803 cells potently suppressed cell invasion and migration as well as expression of MMP-9. Similarly, the combined treatment with COE and LY294002 showed a synergistic effect compared with the treatment with COE or LY294002 alone in MGC-803 cells.

CONCLUSIONS

COE inhibits invasion and migration of MGC-803 cells by reducing MMP-9 expression. It also inhibit PI3K/Akt and NF-κB signaling pathways, which may offer a novel approach for the treatment of human gastric cancer.

Metastatic adenocarcinomas of the stomach or esophagogastric junction (UICC stage IV) are not always a palliative situation: a retrospective analysis

BACKGROUND

Gastric cancer is one of the most common cancers. Unfortunately, it is often diagnosed at the advanced stage International Union Against Cancer stage IV. This induced us to carry out an interdisciplinary analysis of this patient group with the Department of Internal Medicine 1. Our aim was to discuss cancers classified initially as unresectable in a meeting of the interdisciplinary tumor board after palliative chemotherapy, and to refer selected patients for surgery after establishing resectability. The outcome of the chemotherapy, operation method, complication rate, and long-term survival were analyzed.

METHODS

From 1999 to 2008, 76 patients with metastatic gastric cancer or carcinoma of the esophagogastric junction were discussed by the interdisciplinary tumor board of the University of Erlangen and classified initially as unresectable. The patients then received palliative chemotherapy according to the AIO regimen (weekly high-dose 5-fluorouracil/folinic acid [FU/FA] in a 24 h infusion), plus irinotecan. If the tumor was subsequently classified as resectable, the patient underwent either gastric resection or gastrectomy with DII-III dissection. Metastases were resected depending on their location (liver). Peritoneal carcinomatosis was treated additionally by HIPEC. Statistical analysis was with SPSSS version 20.

RESULTS

Surgical and general complications and hospital mortality were acceptable. There were no cases of anastomotic leak, but one patient died of fulminant pneumonia. The R0 resection rate was 69 %, and four patients had long-term survival of more than 60 months. There were significant survival advantages.

CONCLUSIONS

Metastatic gastric cancer or carcinoma of the esophagogastric junction can become resectable after downsizing the tumor with palliative chemotherapy. Long-term survival is achieved in some cases. Therefore, every patient with this type of cancer should be discussed by the interdisciplinary tumour board after palliative chemotherapy to provide him with a chance of cure after re-evaluation.

Decline of serum CA724 as a probable predictive factor for tumor response during chemotherapy of advanced gastric carcinoma

OBJECTIVE

To evaluate the predictive value of decline in the serum level of carbohydrate antigen 724 (CA724) on tumor response during the chemotherapy in patients with advanced gastric carcinoma (GC).

METHODS

The serum CA724 level was determined by electrochemiluminescence immunoassay, while the objective response rate (ORR) was assessed according to response evaluation criteria in solid tumors (RECIST). The association of the changes of serum concentration of CA724 with ORR was analyzed.

RESULTS

The ORR in CA724 (pretreatment serum level) high and low groups was 32.3% (20/62) and 52.8% (19/36), respectively (P=0.045). The relationship between the reduction of CA724 and the ORR was statistically significant (P=0.044). Receiver operating characteristic (ROC) curve established the best cutoff value of the decrease ratio of CA724 as 20.5%.

CONCLUSIONS

CA724 decline seems to indicate chemotherapy efficacy in patients with advanced GC, and an average drop of 20.5% in serum CA724 appears to predict the sensitivity to chemotherapy.

The role of hepatectomy in the management of metastatic gastric adenocarcinoma: a systematic review

BACKGROUND

Gastric cancer has a high mortality, with many patients presenting with advanced disease. Many patients who undergo curative gastrectomy will subsequently develop metastatic disease. Hepatectomy has an established place in treating metastases from a variety of cancers but its role in gastric cancer is not clear. This review sought to systematically appraise the literature to establish the role of hepatectomy in treating gastric cancer metastases.

METHOD

Medline and EMBASE were searched for all papers publishing data on survival of patients with metastatic gastric adenocarcinoma who underwent hepatectomy.

RESULTS

Seventeen studies with 438 patients were included. There were no randomised controlled trials. Perioperative mortality was 2%, with morbidity between 17 and 60%. Patients with solitary metastases appeared to have better survival. Other favourable survival characteristics included unilobar disease, and metachronous presentation. No advantage was demonstrated with either adjuvant or neoadjuvant chemotherapy.

DISCUSSION

Few patients with hepatic metastases from gastric cancer are suitable for hepatectomy, but for those suitable there appears to be survival benefit. Patients with synchronous, multiple or bilobar metastases have worse survival.

CONCLUSION

The evidence supporting the role of hepatectomy in the treatment of hepatic metastases from gastric cancer is weak. However in a selected group there appears to be a survival advantage; patients with solitary metastases had better survival outcomes than those with multiple metastases and metachronous presentation was associated with a better prognosis than synchronous presentation. Hepatectomy should be considered in these patients in the setting of a randomised trial.

miR-137 effects on gastric carcinogenesis are mediated by targeting Cox-2-activated PI3K/AKT signaling pathway

The discovery of microRNAs (miRNAs) provided a new avenue for early diagnosis and treatment of GC. MiR-137 has been reported to be under-expressed and involved in various cell processes. However, the role of miR-137 in GC is less known. In this study, we show that miR-137 is under-expressed in GC and functions as a tumor suppressor through targeting Cyclooxygenase-2 (Cox-2), which subsequently suppresses the activation of PI3K/AKT signaling pathway both in vitro and in vivo. Moreover, restored Cox-2 expression partially abolished the tumor suppressive effects of miR-137 in GC cells, suggesting miR-137 may suppress GC carcinogenesis by targeting Cox-2.

Epidermal growth factor-like domain-containing protein 7 (EGFL7) enhances EGF receptor-AKT signaling, epithelial-mesenchymal transition, and metastasis of gastric cancer cells

Epidermal growth factor-like domain-containing protein 7 (EGFL7) is upregulated in human epithelial tumors and so is a potential biomarker for malignancy. Indeed, previous studies have shown that high EGFL7 expression promotes infiltration and metastasis of gastric carcinoma. The epithelial-mesenchymal transition (EMT) initiates the metastatic cascade and endows cancer cells with invasive and migratory capacity; however, it is not known if EGFL7 promotes metastasis by triggering EMT. We found that EGFL7 was overexpressed in multiple human gastric cancer (GC) cell lines and that overexpression promoted cell invasion and migration as revealed by scratch wound and transwell migration assays. Conversely, shRNA-mediated EGFL7 knockdown reduced invasion and migration. Furthermore, EGFL7-overexpressing cells grew into larger tumors and were more likely to metastasize to the liver compared to underexpressing CG cells following subcutaneous injection in mice. EGFL7 overexpression protected GC cell lines against anoikis, providing a plausible mechanism for this enhanced metastatic capacity. In excised human gastric tumors, expression of EGFL7 was positively correlated with expression levels of the mesenchymal marker vimentin and the EMT-associated transcription repressor Snail, and negatively correlated with expression of the epithelial cell marker E-cadherin. In GC cell lines, EGFL7 knockdown reversed morphological signs of EMT and decreased both vimentin and Snail expression. In addition, EGFL7 overexpression promoted EGF receptor (EGFR) and protein kinase B (AKT) phospho-activation, effects markedly suppressed by the EGFR tyrosine kinase inhibitor AG1478. Moreover, AG1478 also reduced the elevated invasive and migratory capacity of GC cell lines overexpressing EGFL7. Collectively, these results strongly suggest that EGFL7 promotes metastasis by activating EMT through an EGFR-AKT-Snail signaling pathway. Disruption of EGFL7-EGFR-AKT-Snail signaling may a promising therapeutic strategy for gastric cancer.

Maternal embryonic leucine zipper kinase enhances gastric cancer progression via the FAK/Paxillin pathway

Background

Elevated MELK expression is featured in multiple tumors and correlated with tumorigenesis and tumor development. This study is aimed to investigate the mechanisms of MELK-mediated development of gastric cancer.

Methods

MELK expression levels in human gastric cancer were determined by quantitative-PCR and immunohistochemistry. The effect of MELK on cell activity was explored by knockdown and overexpression experiments. Cell growth was measured using the CCK-8 assay. Apoptosis and cell cycle distributions were analyzed by flow cytometry. Migration and invasion were tested using a transwell migration assay. Cytoskeletal changes were analyzed by immunofluorescence. To explore the molecular mechanism and effect of MELK on migration and invasion, Western blotting was used to analyze the FAK/Paxillin pathway and pull down assays for the activity of small Rho GTPases. In vivo tumorigenicity and peritoneal metastasis experiments were performed by tumor cell engraftment into nude mice.

Results

MELK mRNA and protein expression were both elevated in human gastric cancer, and this was associated with chemoresistance to 5-fluorouracil (5-FU). Knockdown of MELK significantly suppressed cell proliferation, migration and invasion of gastric cancer both in vitro and in vivo, decreased the percentages of cells in the G1/G0 phase and increased those in the G2/M and S phases. Moreover, knockdown of MELK decreased the amount of actin stress fibers and inhibited RhoA activity. Finally, knockdown of MELK decreased the phosphorylation of the FAK and paxillin, and prevented gastrin-stimulated FAK/paxillin phosphorylation. By contrast, MELK overexpression had the opposite effect.

Conclusions

MELK promotes cell migration and invasion via the FAK/Paxillin pathway, and plays an important role in the occurrence and development of gastric cancer. MELK may be a potential target for treatment against gastric cancer.

Effect of Yi-Qi-Fu-Sheng Recipe on mucosal barrier in an orthotopic transplant mouse model of gastric cancer

AIM: To investigate the effects of Yi-Qi-Fu-Sheng Recipe (YQFS) on tumor growth and on intestinal mucosal barrier function in mice with experimental gastric cancer.

METHODS: An orthotopic transplant mouse model of gastric cancer was created by injecting mouse MFC cells. Mice were randomly divided into five groups: NS control group, model group, 5-Fu group, YQFS group and combination therapy group. After intragastric administration of drugs for 14 d, tumor growth and the reduced rate of tumor growth were evaluated, the changes in D-lactic acid, diamine oxidase (DAO), endotoxin and IgG were evaluated by ELISA, and the expression of ZO-1 was detected by gelatin zymography.

RESULTS: Compared to the model group, tumor weight in the YQFS group and combination therapy group were significantly decreased (2.29 g ± 0.14 g vs 1.47 g ± 0.10 g, 1.24 g ± 0.11 g, both P < 0.05). Compared to the model group, D-lactic acid, DAO, endotoxin and IgG were decreased after treatment with YQFS (all P < 0.05). Immunohistochemistry analysis revealed that the levels of ZO-1 in the YQFS group, 5-Fu group and combination therapy group were significantly increased compared to the model group (all P < 0.05).

CONCLUSION: YQFS significantly inhibits tumor growth and protects the intestinal mucosal barrier function in mouse with gastric cancer possibly via mechanisms associated with altering the expression of ZO-1.