The members of the miR-148/152 family inhibit cancer stem cell-like properties in gastric cancer via negative regulation of ITGA5

BACKGROUND

The role of microRNA (miRNA) in modulating the function of cancer stem cells through diverse signaling pathway has been evidenced. We here identified a role of microRNA (miRNA) family, specifically miR-148/152, in gastric cancer and delineated its functional effects on gastric cancer stem cells.

METHODS

Bioinformatics analysis was conducted to analyze expression of integrin α5 (ITGA5) which was verified through expression determination in clinical tissue samples. Next, the upstream regulatory factors of ITGA5 were determined. CD44⁺EpCAM (high) cells sorted from AGS cells subjected to gain-of-function experiments, followed by evaluation of their capacity of colony formation, generation of tumorosphere, cell migration and viability in vitro and xenograft tumor formation in vivo.

RESULTS

ITGA5 was elevated in gastric cancer tissues and confirmed as a target gene of the miR-148/152 family members. The miR-148/152 family members were downregulated in gastric cancer tissues and cells. Decreased expression of miR-148/152 family members was also detected in gastric cancer stem cells. However, the raised expression led to reduced colony formation, tumorosphere, cell migration, cell viability, and drug resistance of CD44+EpCAM (high) AGS cells in vitro, and tumorigenesis in vitro. ITGA5 overexpression reversed the effect of the miR-148/152 family members.

CONCLUSIONS

This study demonstrates that the miR-148/152 family members may prevent gastric cancer stem cell-like properties by targeting ITGA5, which can serve as an appealing target for gastric cancer treatment.

circ_0061265 competitively binds to microRNA-885-3p to promote the development of gastric cancer by upregulating AURKA expression

Background

Circular RNAs (circRNAs) represent a class of newly identified transcripts that act as competing endogenous RNAs (ceRNAs) to modulate gene expression by competing for the shared microRNAs (miRNAs) in humans. In this study, we set out to investigate the role of the circRNA-miRNA-mRNA ceRNA network in gastric cancer (GC).

Methods

A differential analysis on GC-related circRNAs, miRNAs and mRNAs was performed utilizing the R language “limma” package, followed by GO and KEGG enrichment analyses. The Cytoscape visualization software was used to construct the circRNA-miRNA-mRNA ceRNA network. RT-qPCR, Western blot assay, immunohistochemistry, RNA pull down, RIP and dual luciferase gene reporter assay were conducted to verify the expression of the related circRNA, miRNA and mRNA and their interaction in GC tissues and cells.

Results

The bioinformatics analysis screened 13 circRNAs, 241 miRNAs and 7483 mRNAs related to GC. Ten DEmRNAs (AURKA, BUB1, CCNF, FEN1, FGF2, ITPKB, CDKN1A, TRIP13, KNTC1 and KIT) were identified from the constructed PPI network and module analysis, among which AURKA was the most critical. A circ_0061265-miRNA-885-3p-AURKA ceRNA network was constructed. In vitro cell experiment demonstrated significantly upregulated circ_0061265 and AURKA, but downregulated miR-885-3p in GC. Moreover, circ_0061265 promoted the occurrence of GC by competitively binding to miRNA-885-3p to regulate AURKA expression.

Conclusion

Our work validated that circ_0061265 may increase AURKA expression by competitively binding to miRNA-885-3p, thereby promoting GC development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02646-3.

LncRNA HOXC-AS1 Sponges miR-99a-3p and Upregulates MMP8, Ultimately Promoting Gastric Cancer

Simple Summary

Long noncoding RNAs, including the HOXC Cluster Antisense RNA 1 (HOXC-AS1), are reported to be critical during the occurrence and progression of gastric cancer. We examined cells and tissues for the expression of HOXC-AS1 and correlated the expression levels with the disease specific survival of the gastric cancer patients. We also identified the interaction between HOXC-AS1 and miR-99a-3p, as well as matrix metalloproteinase 8 (MMP8) by dual-luciferase reporter gene assays. Western blot and qRT-PCR were conducted to verify the alteration in expression levels, while Cell Counting Kit-8 assay and colony formation assay were performed to explore the influences on gastric cancer cells. Overexpression of HOXC-AS1 would accordingly sponge greater quantities of miR-99a-3p, leading to the upregulation of MMP8, eventually facilitating the progress of gastric cancer.

Abstract

Gastric cancer (GC) is among the most lethal tumors worldwide. Long noncoding RNAs (lncRNAs) are reported to be critical during the occurrence and progression of malignancies. The HOXC cluster antisense RNA 1 (HOXC-AS1) has been suggested to participate in the genesis and development of GC. Therefore, we examined GC cells and tissues for the expression of HOXC-AS1 and correlated the expression levels with the disease specific survival of the patients, finding that HOXC-AS1 was overexpressed and probably had a tendency of leading to a poor prognosis. The Cell Counting Kit-8 assay and colony formation assay were then performed under knockdown of HOXC-AS1, revealing that cell proliferation of GC was distinctly decreased. Afterwards, miR-99a-3p was predicted to bind with HOXC-AS1 by DIANA tools. We carried out dual-luciferase reporter gene assays to identify the interaction between them. After knockdown of HOXC-AS1, miR-99a-3p was clearly overexpressed in GC cells. In addition, matrix metalloproteinase 8 (MMP8) was shown to be combined with miR-99a-3p using TargetScan. Similar experiments, along with western blot, were conducted to validate the correlation between miR-99a-3p and MMP8. Finally, rescue experiments for CCK-8 were completed, disclosing that HOXC-AS1 promoted cell progression of GC through sponging miR-99a-3p followed by subsequent upregulation of MMP8.

LncRNA SND1-IT1 facilitates TGF-β1-induced epithelial-to-mesenchymal transition via miR-124/COL4A1 axis in gastric cancer

The transformation of tumor cells from an epithelial to a mesenchymal-like phenotype, designated as epithelial-to-mesenchymal transition (EMT), represents a key hallmark of human cancer metastasis, including gastric cancer (GC). However, a large set of non-coding RNAs have been studied for their functions that initiate or inhibit this phenotypic switch in GC cells by regulating oncogenes or tumor suppressors. In this paper, we aimed to identify lncRNA SND1-IT1, miR-124, and COL4A1 gene in the context of GC with a specific focus on their effects on transforming growth factor β1 (TGF-β1)-induced EMT. The study included 52 paired samples of lesion tissues and adjacent lesion-free tissues surgically resected from patients diagnosed with GC. HGC-27 cells were stimulated with exogenous TGF-β1 (2 ng/mL). Expression of lncRNA SND1-IT1, miR-124, and COL4A1 was determined by RT-qPCR. CCK-8 assays, Transwell assays, immunoblotting analysis of EMT-specific markers, and tumor invasion markers were performed to evaluate cell viability, migration, and invasion of cultured HGC-27 cells. Luciferase activity assay was employed to examine miR-124 binding with lncRNA SND1-IT1 and COL4A1, respectively. LncRNA SND1-IT1 was upregulated in GC tissues and cells. TGF-β1-stimulated EMT and regulated lncRNA SND1-IT1, miR-124, and COL4A1 expressions in HGC-27 cells. LncRNA SND1-IT1 knockdown tempered HGC-27 cell viability, migration and invasion. LncRNA SND1-IT1 participated in TGF-β1-stimulated EMT in GC by sponging miR-124. MiR-124 attenuated TGF-β1-stimulated EMT in GC by targeting COL4A1. These results primarily demonstrated TGF-β1 can regulate cancer cell migration, invasion and stimulate EMT through the SND1-IT1/miR-124/COL4A1 axis in GC.

Discriminating Epithelial to Mesenchymal Transition Phenotypes in Circulating Tumor Cells Isolated from Advanced Gastrointestinal Cancer Patients

Gastrointestinal (GI) cancers constitute a group of highest morbidity worldwide, with colorectal cancer (CRC) and gastric cancer being among the most frequently diagnosed. The majority of gastrointestinal cancer patients already present metastasis by the time of diagnosis, which is widely associated with cancer-related death. Accumulating evidence suggests that epithelial-to-mesenchymal transition (EMT) in cancer promotes circulating tumor cell (CTCs) formation, which ultimately drives metastasis development. These cells have emerged as a fundamental tool for cancer diagnosis and monitoring, as they reflect tumor heterogeneity and the clonal evolution of cancer in real-time. In particular, EMT phenotypes are commonly associated with therapy resistance. Thus, capturing these CTCs is expected to reveal important clinical information. However, currently available CTC isolation approaches are suboptimal and are often targeted to capture epithelial CTCs, leading to the loss of EMT or mesenchymal CTCs. Here, we describe size-based CTCs isolation using the RUBYchip™, a label-free microfluidic device, aiming to detect EMT biomarkers in CTCs from whole blood samples of GI cancer patients. We found that, for most cases, the mesenchymal phenotype was predominant, and in fact a considerable fraction of isolated CTCs did not express epithelial markers. The RUBYchip™ can overcome the limitations of label-dependent technologies and improve the identification of CTC subpopulations that may be related to different clinical outcomes.

Circular CPM promotes chemoresistance of gastric cancer via activating PRKAA2-mediated autophagy

BACKGROUND

Chemotherapy can significantly improve the disease-free survival and overall survival of patients with advanced gastric cancer (GC). 5-fluorouracil (5-FU) is frequently applied in the clinic, acting as a first-line chemotherapy drug of advanced GC, which could be used alone or combining platinum drugs. However, its efficacy is significantly attenuated by chemoresistance, which is associated with patients' poor survival. Recently, there is evidence suggesting that dysregulation of autophagy may contribute to drug resistance in cancer, and circular RNAs (circRNAs) also take part in chemoresistance. However, whether circRNAs participate in 5-FU chemoresistance through autophagy remains largely unknown.

METHODS

RNA sequencing technologies and bioinformatics analysis were performed in GC. Sanger sequencing, Actinomycin D assay and RNase R assay confirmed the circular structure of circular CPM (circCPM). Various cell line models and animal models were used to explore related functions in vitro and in vivo. Quantitative Real-time PCR (qRT-PCR), fluorescence in situ hybridization, ribonucleic acid; (RNA) pulldown assays, RNA binding protein immunoprecipitation assays and Luciferase reporter assays were applied to explore involved pathways.

RESULTS

circCPM was up-regulated in 5-FU resistant GC cell lines and tissue. Moreover, high circCPM expression is positively associated with poor survival. Silencing circCPM greatly improved chemosensitivity in vitro and in vivo. Mechanistically, it directly binds to miR-21-3p in the cytoplasm and therefore increases the expression of PRKAA2, contributing to the activation of autophagy and chemoresistance.

CONCLUSION

Our results reveal that circCPM has a crucial role in regulating GC autophagy and 5-FU resistance by targeting PRKAA2. It may function as a new theory basis for assessing the curative effect of GC and reversing 5-FU chemoresistance.

Potent synergistic anti-tumor activity of a novel humanized anti-HER2 antibody hersintuzumab in combination with trastuzumab in xenograft models

Immunotherapy of HER2-overexpressing cancers by FDA approved monoclonal antibodies (mAbs) such as trastuzumab and pertuzumab has shown promising results. We have recently produced a novel humanized anti-HER2 mAb, hersintuzumab, which did not sterically inhibit binding of trastuzumab and pertuzumab to HER2, thus recognizing a distinct epitope on subdomain I + II of HER2. In this study, we assessed the in vitro and in vivo anti-tumor activity of this mAb individually and in combination with trastuzumab. Different HER2-overexpressing human cancer cell lines, including SKOV3, NCI-N87 HCC1954 and BT-474 were cultured and binding reactivity of Hersintuzumab to these cell lines was analyzed by flow cytometry. In addition, the inhibitory effect of different concentrations of hersintuzumab, trastuzumab and their combination on tumor cells growth was assessed by XTT assay. For Assessment of tumor growth inhibition in xenograft model, Balb/c athymic nude mice were subcutaneously injected with NCI-N87 and SKOV3 tumor cells and then treated intravenously with these mAbs. Our results showed that hersintuzumab could bind to all HER2-overexpressing cell lines similar to trastuzumab. In vitro experiments showed that both hersintuzumab and trastuzumab individually and in combination inhibited growth of all cell lines with the exception of HCC-1954.Inhibitory effect of the combination of mAbs was significantly higher than that of each mAb alone. Similar results were obtained in the gastric (NCI-N87) and ovarian (SKOV-3) tumor xenograft models. Hersintuzumab in combination with trastuzumab induces synergic anti-tumor effects on HER2-overexpressing cells in vitro and in vivo and is potentially a therapeutic tool for treatment of HER2-overexpressing cancers.

Conversion surgery for metastatic gastric cancer at 2 years after initial diagnosis of cancer of unknown primary with metastasis of cervical lymph nodes and ovary: a case report

Background

Patients with stage IV gastric cancer have a poor prognosis despite improvements in intensive treatment regimens, including chemotherapy. Recently, conversion surgery has received much attention as it can provide long-term survival in stage IV gastric cancer patients who are responsive to chemotherapy. Herein, we describe the case of a patient who underwent conversion surgery for metastatic gastric cancer that was performed over 2 years after an initial diagnosis of cancer of unknown primary (CUP) with metastasis of the cervical lymph nodes and the ovary.

Case presentation

A 67-year-old woman with cervical lymphadenopathy was referred to our hospital. Computed tomography showed left cervical lymphadenopathy and bilateral ovarian enlargement. Endoscopic survey revealed no signs of malignancy in the upper or the lower gastrointestinal tract. Pathological findings after cervical lymphadenectomy revealed a signet-ring cell carcinoma and were suggestive of gastric cancer metastases. However, multiple evaluations yielded no evidence of gastric cancer and the patient was diagnosed with CUP. She was prescribed chemotherapy for gastric cancer and underwent bilateral oophorectomy after undergoing chemotherapy for 18 months. Pathologic analysis of oophorectomy tissue revealed findings identical to those seen in the cervical lymph nodes. At about 2 years after the initial diagnosis, an esophagogastroduodenoscopy revealed evidence of gastric cancer. We performed a distal gastrectomy with D2 lymphadenectomy. Her postoperative course was uneventful and she remains alive with no signs of disease recurrence at 3 months post-surgery.

Conclusions

To the best of our knowledge, this is the first report describing successful conversion surgery for stage IV gastric cancer in a patient whose cancer was definitively diagnosed 2 years after an initial diagnosis of CUP.

miR-300/FA2H affects gastric cancer cell proliferation and apoptosis

MicroRNA (miR/miRNA) expression disorders play a crucial role in the development of gastric cancer (GC). Increasing evidence has indicated that miRNAs participate in the process of numerous cancers. Previous research has demonstrated that miR-300 acts as a cancer-promoting factor or tumor suppressor in a number of tumors. However, to the best of our knowledge, the effects of miR-300 on GC cells remain largely unknown. The present study investigated the effects of miR-300 on GC cells and analyzed its molecular mechanism. First, reverse transcription-quantitative polymerase chain reaction showed that miR-300 expression was increased in GC tissues and cell lines, with the highest expression observed in human gastric cancer cell line AGS. Subsequent results indicated that fatty acid 2-hydroxylase (FA2H) was a target of miR-300. FA2H-plasmid inhibited AGS cell proliferation and induced apoptosis. Finally, miR-300 inhibitor reduced cell proliferation and induced apoptosis, whereby these effects were reversed by FA2H-small interfering RNA. Therefore, the data demonstrated that miR-300/FA2H might be a new potential biomarker and therapeutic target for GC treatment.

[Differential diagnostics of gastric cancer and precancerous changes of the gastric mucosa using analysis of expression of six microRNAS.]

The lack of specific symptoms for the early detection of gastric cancer leads to the fact that it is often diagnosed at a late stage, when the prognosis is unfavorable. The analysis of molecular markers in addition to standard diagnostic procedures is a promising approach for improving the preoperative diagnosis of both gastric cancer and precancerous changes in the mucosa. Therefore, the aim of our study was to analyze the diagnostic significance of using miRNA expression to diagnosis gastric cancer and precancerous conditions (dysplasia) in histological material. In this work, 122 samples of archival histological material in the form of paraffin blocks were used: 34 samples of gastric adenocarcinoma, 54 samples of gastric ulcers with dysplasia and 34 samples of normal gastric mucosa obtained from patients after bariatric surgery. The expression level of miRNA-145-5p, -150-5p, -20a-5p, -21-5p, -31-5p, -34a-5p, -375 was determined using real-time RT-PCR. Samples were stratified into different groups using the C-RT decision tree algorithm. All miRNAs, except miRNA-20a, were included in the decision tree, which allows stratification of samples for normal mucosa, dysplasia, and gastric cancer. Normal mucosa can be distinguished from gastric cancer only by miRNA-34a, -21, -375. Diagnostic characteristics for the detection of dysplasia: specificity - 97%, sensitivity - 87%; for the detection of gastric cancer: specificity - 91%, sensitivity - 93%. The sufficiently high values of the diagnostic characteristics for detecting dysplasia of the gastric mucosa and gastric cancer obtained in our study indicate the possibility of using expression data of a small amount of miRNAs for the effective separation of samples with tumor and precancerous changes in the stomach tissue.

MicroRNA-498 inhibits the proliferation, migration and invasion of gastric cancer through targeting BMI-1 and suppressing AKT pathway

Recently, microRNA-498 (miR-498) plays important effect in human cancers. Nonetheless, the role of miR-498 is still unclear in gastric cancer (GC). Therefore, this study was designed to investigate the function of miR-498 in GC tissues and cell lines (SGC-7901, BGC-823, MGC-803). The expressions of miR-498 and BMI-1 were examined in GC tissues via the RT-qPCR assay. The function of miR-498 was investigated through MTT and transwell assays. The relationship between miR-498 and BMI-1 was testified by dual luciferase assay. The protein expression of EMT markers, AKT pathway markers and BMI-1 was measured through western blot. The expression of miR-498 was decreased in GC tissues which predicted poor prognosis of GC patients. Moreover, functional analyses show that the overexpression of miR-498 inhibited the progression of GC. Furthermore, BMI-1 was a direct target of miR-498 which was upregulated in GC. Especially, the upregulation of BMI-1 recovered the suppressive effect of miR-498 in GC. In addition, miR-498 inhibited the metastasis and proliferation of GC cells through blocking EMT and AKT pathway. MiR-498, by targeting BMI-1, presents a plethora of tumor suppressor activities in GC cells.

Celastrol Induces Necroptosis and Ameliorates Inflammation via Targeting Biglycan in Human Gastric Carcinoma

Celastrol, a triterpene isolated from the root of traditional Chinese medicine Thunder of God Vine, possesses anti-cancer and anti-inflammatory activity to treat rheumatoid disease or as health product. Necroptosis is considered as a new approach to overcome chemotherapeutics resistance. However, whether celastrol exerts necroptosis leading to gastric cancer cell death is still unclear. Here, for the first time we showed that celastrol induced necroptosis in HGC27 and AGS gastric cancer cell lines. More importantly, celastrol down-regulated biglycan (BGN) protein, which is critical for gastric cancer migration and invasion. Furthermore, celastrol activated receptor-interacting protein 1 and 3 (RIP1 and RIP3) and subsequently promoted the translation of mixed-lineage kinase domain-like (MLKL) from cytoplasm to plasma membrane, leading to necroptosis of gastric cancer cell, which was blocked by over-expression BGN. In addition, celastrol suppressed the release of pro-inflammatory cytokines TNF-α and IL-8 in HGC27 and AGS cells, which was reversed by over-expression BGN. Taken together, we identified celastrol as a necroptosis inducer, activated RIP1/RIP3/MLKL pathway and suppressed the level of pro-inflammatory cytokines by down-regulating BGN in HGC-27 and AGS cells, which supported the feasibility of celastrol in gastric cancer therapy.

Anticancer effects and underlying mechanism of Colchicine on human gastric cancer cell lines in vitro and in vivo

The present study investigated the effects of Colchicine on gastric carcinoma (GC) cells and explored its possible mechanisms underlying such effects. The results of MTT and colony formation assays showed that Colchicine (2, 5, and 10 ng/ml) markedly inhibited the proliferation of AGS and NCI-N87 cells in a dose-dependent manner. It also led to a reduction in cell migration in both GC cells as determined by Transwell migration assay. Mover, data form Hoechst 33342 staining and flow cytometry assay indicated that Colchicine (2, 5, and 10 ng/ml) promoted the apoptosis of NCI-N87 cells. In addition, the release of cytochrome c, the activation of bax, and the inhibition of bcl-2 were observed in NCI-N87 cells treated with Colchicine. Furthermore, the in vivo experiment further confirmed that Colchicine administration remarkably suppressed the tumor growth in nude mice via induction of apoptosis at 0.05 and 0.1 mg/kg. In addition, no visible toxicity was observed in liver and renal tissue of mice. This finding suggests that Colchicine-induced apoptosis is associated with caspase-3-mediated mitochondrial apoptotic pathways.

In Vitro Characterization and Evaluation of the Cytotoxicity Effects of Nisin and Nisin-Loaded PLA-PEG-PLA Nanoparticles on Gastrointestinal (AGS and KYSE-30), Hepatic (HepG2) and Blood (K562) Cancer Cell Lines

The aim of this study was an in vitro evaluation and comparison of the cytotoxic effects of free nisin and nisin-loaded PLA-PEG-PLA nanoparticles on gastrointestinal (AGS and KYSE-30), hepatic (HepG2), and blood (K562) cancer cell lines. To create this novel anti-cancer drug delivery system, the nanoparticles were synthesized and then loaded with nisin. Subsequently, their biocompatibility, ability to enter cells, and physicochemical properties, including formation, size, and shape, were studied using hemolysis, fluorescein isothiocyanate (FITC), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), respectively. Then, its loading efficiency and release kinetics were examined to assess the potential impact of this formulation for the nanoparticle carrier candidacy. The cytotoxicities of nisin and nisin-loaded nanoparticles were evaluated by using the MTT and Neutral Red (NR) uptake assays. Detections of the apoptotic cells were done via Ethidium Bromide (EB)/Acridine Orange (AO) staining. The FTIR spectra, SEM images, and DLS graph confirmed the formations of the nanoparticles and nisin-loaded nanoparticles with spherical, distinct, and smooth surfaces and average sizes of 100 and 200 nm, respectively. The loading efficiency of the latter nanoparticles was about 85-90%. The hemolysis test represented their non-cytotoxicities and the FITC images indicated their entrance inside the cells. An increase in the percentage of apoptotic cells was observed through EB/AO staining. These results demonstrated that nisin had a cytotoxic effect on AGS, KYSE-30, HepG2, and K562 cancer cell lines, while the cytotoxicity of nisin-loaded nanoparticles was more than that of the free nisin.

miR-1236-3p inhibits invasion and metastasis in gastric cancer by targeting MTA2

Background

MicroRNAs deregulation are common in human tumor progression. miR-1236-3p has been reported to function as tumor suppressor microRNA in various malignancies. The aim of this study was to demonstrate the downregulated expression of miR-1236-3p in gastric cancer (GC) tissues and cell lines, and clarify its biological function in GC.

Methods

Real-time polymerase chain reaction was used to measure the mRNA level of miR-1236-3p in GC. Dual luciferase assay was used to demonstrate that MTA2 was one of the candidate target genes of miR-1236-3p. Western blots were utilized to detect the protein levels. Cell function assays were also performed to determine the function of miR-1236-3p in GC.

Results

miR-1236-3p expression, which was associated with lymph node metastasis, differentiation and clinical stage, was significantly reduced in GC tissues and cell lines. miR-1236-3p over-expression could inhibit GC cell proliferation, migration and invasion, and inhibition of miR-1236-3p expression had opposite effects. Furthermore, we demonstrated that MTA2 was a candidate target of miR-1236-3p, and miR-1236-3p over-expression significantly inhibited the process of epithelial-mesenchymal transition. We also found that miR-1236-3p could suppress the PI3K/Akt signaling pathway in GC cells.

Conclusions

Our results suggest that miR-1236-3p functions as a tumor suppressor in GC and could be a promising therapeutic target for GC.

Pharmacological inhibition of DUSP6 suppresses gastric cancer growth and metastasis and overcomes cisplatin resistance

Gastric cancer (GC) is the second cause of cancer-related death. Cisplatin (CDDP) is widely used as the standard GC treatment, but relapse and metastasis are common because of intrinsic or acquired drug resistance. The mitogen-activated protein kinase phosphatases (MAPK)-extracellular signal regulated kinases (ERK) pathway contributes to GC progression and drug resistance, but targeting the MAPK-ERK pathway is challenging in GC therapy. Here, we demonstrated that dual-specificity phosphatases 6 (DUSP6) was overexpressed in GC and predicted poor overall survival and progression-free survival. Knockdown DUSP6 inhibited GC proliferation, migration, invasion and induced apoptosis. (E/Z)-BCI hydrochloride (BCI), a DUSP6 small molecule inhibitor, increased the activity of ERK but interestingly decreased the expression of ERK response genes in BGC823, SGC7901 and CDDP-resistant SGC7901/DDP cells. BCI also caused cell death through the DNA damage response (DDR) pathway. Moreover, BCI inhibited cell proliferation, migration and invasion in a receptor-independent manner and enhanced CDDP cytotoxicity at pharmacological concentrations in the GC cells. In vivo experiments further showed that BCI enhances the antitumor effects of CDDP in cell-based xenografts and PDX models. In summary, our findings indicated that disruption of DUSP6 by BCI enhanced CDDP-induced cell death and apoptosis in GC may partly through ERK and DDR pathways. Thus, this study suggests that DUSP6 is a potential prognostic biomarker and a promising target for GC therapy.

Ailanthone induces G2/M cell cycle arrest and apoptosis of SGC‑7901 human gastric cancer cells

Ailanthone is a major quassinoid extracted from the Chinese medicinal herb Ailanthus altissima, which has been reported to exert antiproliferative effects on various cancer cells. The present study aimed to investigate the antitumor effects of ailanthone on SGC-7901 cells, and to analyze its underlying molecular mechanisms. Following treatment with ailanthone, Cell Counting kit-8 was used to detect the cytotoxic effects of ailanthone on SGC-7901 cells in vitro. The typical apoptotic morphology of SGC-7901 cells was observed by Hoechst 33258 staining. Cell cycle progression and apoptosis were measured by flow cytometry, and the protein and mRNA expression levels of Bcl-2 and Bax were analyzed by western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) respectively, in SGC-7901 cells. The results of the present study indicated that ailanthone inhibited the proliferation of SGC-7901 cells in a dose- and time-dependent manner in vitro, and also demonstrated that ailanthone induced G₂/M phase cell cycle arrest and apoptosis of SGC-7901 cells. Furthermore, analysis of the underlying molecular mechanisms revealed that ailanthone downregulated the expression levels of Bcl-2, whereas the expression levels of Bax were upregulated at the protein and mRNA levels. In conclusion, ailanthone may inhibit the proliferation of SGC-7901 cells by inducing G₂/M phase cell cycle arrest and apoptosis via altering the protein and mRNA expression levels of Bcl-2 and Bax in SGC-7901 cells.

New bioactive peptide reduces the toxicity of chemotherapy drugs and increases drug sensitivity

Anticancer bioactive peptide (ACBP) is extracted from normal goat spleens and exhibits antitumor activity alone and in combination with low cisplatin doses to achieve antitumor efficacy similar to higher cisplatin doses via sustained medication modes. In the present study, we investigated whether elevated levels of induced or normal ACBP in MKN‑45 gastric cancer (GC) cells may reduce their toxicity to oxaliplatin (L‑OHP) in a dose‑dependent manner. The growth inhibition rate (IR), morphological changes and gene expression were examined in MKN‑45 GC cells. Compared with normal ACBP, induced ACBP alone significantly enhanced the anticancer activity of L‑OHP‑mediated apoptosis and reduced the amount and side‑effects of L‑OHP (P<0.05). The inhibition of cancer cell growth at high concentrations of induced ACBP and L‑OHP was significantly more effective than at low concentrations. In addition, for the first time, we examined the potential of a combination of induced ACBP and L‑OHP to increase L‑OHP sensitivity in human gastric carcinoma xenograft tumors. Nude mice were implanted with human gastric carcinoma MKN‑45 cells and treated with an intraperitoneal injection of 0.5 ml of normal saline, 30 µg/ml ACBP, 20 µg/ml L‑OHP or 30 µg/ml ACBP + 20 µg/ml L‑OHP [combination of anticancer bioactive peptide and oxaliplatin (A+L)] via the tail vein twice a week. In vivo short‑term intermittent use of induced ACBP alone significantly inhibited MKN‑45 tumor growth. The combination of induced ACBP and L‑OHP also significantly improved the quality of life of the nude mice and reduced the toxicity of L‑OHP. Based on flow cytometry and gene expression analyses, A+L significantly increased the proportion of cells in the G2/M phase (P<0.05) relative to ACBP or L‑OHP alone, and short‑term intraperitoneal injection of ACBP increased the sensitizing effect of L‑OHP. Collectively, these results suggest that high levels of induced ACBP in combination with L‑OHP via a short‑term intermittent medication mode could be a useful clinical therapeutic strategy for GC.

Nuclear heat shock protein 110 expression is associated with poor prognosis and chemotherapy resistance in gastric cancer

Heat shock protein (HSP) expression is induced by the exposure to stress, such as fever, oxidative stress, chemical exposure, and irradiation. In cancer, HSP promotes the survival of malignant cells by inhibiting the induction of apoptosis. In colorectal cancer, a loss-of-function mutation of HSP110 (HSP110ΔE9) has been identified. HSP110ΔE9 inhibits the nuclear translocation of wild-type HSP110, which is important for its chaperone activity and anti-apoptotic effects. The patients carrying HSP110ΔE9 mutation exhibit high sensitivity to anticancer agents, such as oxaliplatin and 5-fluorouracil. There is still insufficient information about HSP110 localization, the clinicopathological significance of HSP110 expression, and its association with chemotherapy resistance in gastric cancer. Here, we found that high nuclear expression of HSP110 in gastric cancer tissues is associated with cancer progression, poor prognosis, and recurrence after adjuvant chemotherapy. In vitro results showed that HSP110 suppression increases the sensitivity to 5-fluorouracil and cisplatin of human gastric cancer cell lines. Our results suggest that nuclear HSP110 may be a new drug sensitivity marker for gastric cancer and a potential molecular therapeutic target for the treatment of gastric cancer patients with acquired anticancer drug resistance.

Sulforaphane improves chemotherapy efficacy by targeting cancer stem cell-like properties via the miR-124/IL-6R/STAT3 axis

Gastric carcinoma (GC) is the second leading cause of cancer-related mortality worldwide. The efficacy of standard chemotherapy for GC, such as cisplatin (CDDP), is dissatisfactory partly due to the toxic/side-effects. Sulforaphane (SFN), which exhibits effective anti-cancer functions, is a phytochemical converted from cruciferous plants. Our present study aimed to identify whether SFN could enhance the anti-cancer effects of low-dose CDDP and to determine the underlying mechanisms. Herein, co-exposure of SFN and CDDP significantly inhibited the viabilities of gastric cancer cells. For the molecular mechanisms, CDDP alone increased the cancer stem cell (CSC)-like properties in gastric cancer cells via activating the interleukin-6 (IL-6)/IL-6 receptor (IL-6R)/signal transducer and activator of transcription 3 (STAT3) signaling. However, SFN could activate the microRNA-124 (miR-124), which directly targets the 3'-untranslated regions (UTR) of the IL-6R and STAT3. Moreover, knockdown of miR-124 eliminated the effects of SFN on CSC-like properties in GC cells, and in turn enhanced the anti-cancer effects of low-dose CDDP. These findings not only suggested a mechanism whereby SFN enhanced the anti-cancer functions of CDDP, but also helped to regard SFN as a potential chemotherapeutic factor in gastric cancer.

Relationship Between 18F-FDG PET/CT Findings and HER2 Expression in Gastric Cancer

(18)F-FDG PET has been widely used in the management of malignant tumors. In gastric cancer, the status of human epidermal growth factor receptor 2 (HER2) predicts the response to anti-HER2 antibody therapy, and testing of HER2 expression is now routine in the management of gastric cancer patients. However, to date, the relationship between (18)F-FDG uptake and HER2 expression has not, to our knowledge, been investigated. In this study, we aimed to investigate whether HER2 expression is associated with (18)F-FDG uptake and whether (18)F-FDG PET/CT can be used to predict the HER2 status of gastric cancer.

METHODS

A retrospective analysis was performed on 64 gastric cancer patients who had undergone (18)F-FDG PET/CT before surgical resection. Tumor SUVmax was calculated from the level of (18)F-FDG uptake.

RESULTS

No significant correlation was found between SUVmax and HER2 expression in gastric cancer. However, when signet-ring cell carcinoma was excluded, SUVmax was significantly higher in the HER2-negative group than in the HER2-positive group (8.619 ± 5.878 vs. 3.789 ± 2.613, respectively; P = 0.021). Multivariate analysis indicated that SUVmax and tumor differentiation remained significantly associated with HER2 expression (P = 0.048 and P = 0.028, respectively). HER2 expression was predicted with an accuracy of 64.4% when an SUVmax cutoff of 6.2 was used.

CONCLUSION

(18)F-FDG uptake by gastric cancer is associated with HER2 expression. (18)F-FDG PET/CT may be useful for predicting the HER2 status of gastric cancer and for determining the therapeutic strategy.

Lupeol enhances inhibitory effect of 5-fluorouracil on human gastric carcinoma cells

Lupeol, a dietary triterpene present in many fruits and medicinal plants, has been reported to possess many pharmacological properties including cancer-preventive and anti-cancer effects in vitro and in vivo. Here, we investigated the anti-cancer efficacy and adjuvant chemotherapy action of lupeol in gastric cancer (GC) cells (SGC7901 and BGC823) and explored the underlying mechanisms. Cells were treated with lupeol and/or 5-fluorouracil (5-Fu) and subjected to cell viability, colony formation, apoptosis, western blot, semiquantitative RT-PCR, and xenograft tumorigenicity assay. Our results showed that lupeol and 5-Fu inhibited the proliferation of SGC7901 and BGC823 cells, and combination treatment with lupeol and 5-Fu resulted in a combination index < 1, indicating a synergistic effect. Co-treatment with lupeol and 5-Fu induced apoptosis through up-regulating the expressions of Bax and p53 and down-regulating the expressions of survivin and Bcl-2. Furthermore, co-treatment displayed more efficient inhibition of tumor weight and volume on BGC823 xenograft mouse model than single-agent treatment with 5-Fu or lupeol. Taken together, our findings highlight that lupeol sensitizes GC to 5-Fu treatment, and combination treatment with lupeol and 5-Fu would be a promising therapeutic strategy for human GC treatment.

Effect of EGFR and p-AKT Overexpression on Chromosomal Instability in Gastric Cancer

BACKGROUND

Molecular profiling in gastric cancer (GC) is important for diagnosis and treatment. In this study, we investigated signal transduction pathways that might induce chromosomal instability in GC.

METHODS

Epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and p-AKT expression were analyzed using immunohistochemistry, and chromosomal instability was assessed by DNA aneuploidy using laser scanning cytometry, in a total of 202 GC cases.

RESULTS

The rate of EGFR expression and p-AKT expression was 70.3 and 34.2 %, respectively, in GC patients. In total, 57.5 % of GC patients exhibited DNA aneuploidy, and p-AKT positively correlated with EGFR and HER2 (p = 0.0127 and p = 0.00031, respectively). Patients with EGFR overexpressing GC showed shorter disease-specific survival than the other cases (hazard ratio 2.00, 95 % confidence interval 1.19-3.53; p = 0.0104). Moreover, EGFR and p-AKT expression was significantly correlated with DNA aneuploidy (p = 0.0002 and p = 0.0302, respectively).

CONCLUSIONS

Our data showed that both EGFR and p-AKT overexpression were clearly associated with DNA aneuploidy. Aneuploidy could be a useful marker for therapies that target EGFR.

Systematic review on quality of life outcomes after gastrectomy for gastric carcinoma

BACKGROUND

Despite advances in chemotherapy and radiotherapy, gastrectomy is the only curative intervention for gastric carcinoma. This study reviews post-operative health-related quality of life (HRQOL) after gastrectomy.

METHODS

A literature search was conducted on PubMed for all studies published after January 2000 matching strict eligibility criteria. Bibliographies of included studies were also reviewed. Quality appraisal and data tabulation were performed using pre-determined forms. Results were synthesised by narrative review according to PRISMA guidelines with full tabulation of results of all included studies.

RESULTS

A total of 21 studies (3,575 patients) were included. Post-operative HRQOL improvements were demonstrated across most or all domains in different HRQOL instruments. Patients experienced declines in HRQOL 1 month after surgery, but reached at least pre-operative levels with recovery by 1 year. The greatest improvements were demonstrated in the emotional health domain with favourable functional benefits. Partial gastrectomy appears to be superior to total gastrectomy in physical, emotional and functional health domains. However, patients remain susceptible to gastrointestinal symptoms following surgery, which negatively impact upon HRQOL. Post-operative complications did not appear to affect HRQOL. Most studies were prospective, but data is heterogeneous.

CONCLUSIONS

Gastrectomy results in significant HRQOL benefits across a broad range of health domains. This is critical outcome of surgery and an important consideration in pre-operative decision making.

The use of high-throughput screening in identifying chemotherapeutic agents for gastric cancer

Gastric cancer claims many lives around the world, particularly in Asia. Although diagnosis and treatment has improved, long-term survival of patients is still poor and there is an urgent need to develop more effective treatments for this disease. This review outlines some of the more innovative high-throughput screening-based approaches and strategies that may be used to identify compounds that have new or novel mechanisms of action and could be developed further as possible gastric cancer treatments in the future.

Celastrol inhibits gastric cancer growth by induction of apoptosis and autophagy

Recently, the interest in natural products for the treatment of cancer is increasing because they are the pre-screened candidates. In the present study, we demonstrate the therapeutic effect of celastrol, a triterpene extracted from the root bark of Chinese medicine on gastric cancer. The proliferation of AGS and YCC-2 cells were most sensitively decreased in six kinds of gastric cancer cell lines after the treatment with celastrol. Celastrol inhibited the cell migration and increased G1 arrest in cell-cycle populations in both cell lines. The treatment with celastrol significantly induced autophagy and apoptosis and increased the expression of autophagy and apoptosis-related proteins. We also found an increase in phosphorylated AMPK following a decrease in all phosphorylated forms of AKT, mTOR and S6K after the treatment with celastrol. Moreover, gastric tumor burdens were reduced in a dose-dependent manner by celastrol administration in a xenografted mice model. Taken together, celastrol distinctly inhibits the gastric cancer cell proliferation and induces autophagy and apoptosis. [BMB Reports 2014; 47(12): 697-702]

Current status of randomized controlled trials for laparoscopic gastric surgery for gastric cancer in China

China alone accounts for nearly 42% of all new gastric cancer cases worldwide, and gastric cancer is the third leading cause of cancer deaths in China nowadays. Without mass screening programs, unfortunately over 80% of all Chinese patients have been diagnosed as advanced diseases. As in other Asian countries, especially Japan and Korea, laparoscopic gastrectomy for the treatment of gastric cancer has gained increasingly popularity in China during the past decade. Whether laparoscopic surgery can be safely and effectively performed in the treatment of gastric cancer remains controversial, particularly with regard to curative intent in advanced diseases. Given the high incidence of these cancers, and their advanced stage at diagnosis, China has a significant interest in determining the safety and effectiveness of laparoscopic gastrectomy. A well-designed randomized controlled trial (RCT) is considered the only feasible way to provide conclusive evidence. To date, China has not played a significant role in terms of conducting RCT concerning laparoscopic surgery for gastric cancer. However, an effort has been made by the Chinese researchers, with the great help from our colleagues in neighboring countries such as Korea and Japan, through the establishment of the Chinese Laparoscopic Gastrointestinal Surgery Study Group. In this review, we present the current status of RCT for laparoscopic gastric surgery for gastric cancer in China, including published and ongoing registered RCT.

Upregulation of autophagy-related gene-5 (ATG-5) is associated with chemoresistance in human gastric cancer

Autophagy-related gene-5 (ATG-5) is one of the key regulators of autophagic cell death. It has been widely regarded as a protective molecular mechanism for tumor cells during the course of chemotherapy. In the present study, we investigated the expression pattern of ATG-5 and multidrug resistance-associated protein-1 (MRP-1) in 135 gastric cancers (GC) patients who were treated with epirubicin, cisplatin and 5-FU adjuvant chemotherapy (ECF) following surgical resection and explored their potential clinical significance. We found that both ATG-5 (77.78%) and MRP-1 (79.26%) were highly expressed in GC patients. ATG-5 expression was significantly associated with depth of wall invasion, TNM stages and distant metastasis of GC (P<0.05), whereas MRP-1 expression was significantly linked with tumor size, depth of wall invasion, lymph node metastasis, TNM stages and differentiation status (P<0.05). ATG-5 expression was positively correlated with MRP-1 (rp = 0.616, P<0.01). Increased expression of ATG-5 and MPR-1 was significantly correlated with poor overall survival (OS; P<0.01) and disease free survival (DFS; P<0.01) of our GC cohort. Furthermore, we demonstrated that ATG-5 was involved in drug resistant of GC cells, which was mainly through regulating autophagy. Our data suggest that upregulated expression of ATG-5, an important molecular feature of protective autophagy, is associated with chemoresistance in GC. Expression of ATG-5 and MRP-1 may be independent prognostic markers for GC treatment.

MicroRNAs as potential biomarkers for gastric cancer

Gastric cancer is the fourth most common cancer in the world and the second leading cause of cancer-related death. More than 80% of diagnoses occur at the middle to late stage of the disease, highlighting an urgent need for novel biomarkers detectable at earlier stages. Recently, aberrantly expressed microRNAs (miRNAs) have received a great deal of attention as potential sensitive and accurate biomarkers for cancer diagnosis and prognosis. This review summarizes the current knowledge about potential miRNA biomarkers for gastric cancer that have been reported in the publicly available literature between 2008 and 2013. Available evidence indicates that aberrantly expressed miRNAs in gastric cancer correlate with tumorigenesis, tumor proliferation, distant metastasis and invasion. Furthermore, tissue and cancer types can be classified using miRNA expression profiles and next-generation sequencing. As miRNAs in plasma/serum are well protected from RNases, they remain stable under harsh conditions. Thus, potential functions of these circulating miRNAs can be deduced and may implicate their diagnostic value in cancer detection. Circulating miRNAs, as well as tissue miRNAs, may allow for the detection of gastric cancer at an early stage, prediction of prognosis, and monitoring of recurrence and/or lymph node metastasis. Taken together, the data suggest that the participation of miRNAs in biomarker development will enhance the sensitivity and specificity of diagnostic and prognostic tests for gastric cancer.

Endoscopic surveillance strategy after endoscopic resection for early gastric cancer

Early detection of early gastric cancer (EGC) is important to improve the prognosis of patients with gastric cancer. Recent advances in endoscopic modalities and treatment devices, such as image-enhanced endoscopy and high-frequency generators, may make endoscopic treatment, such as endoscopic submucosal dissection, a therapeutic option for gastric intraepithelial neoplasia. Consequently, short-term outcomes of endoscopic resection (ER) for EGC have improved. Therefore, surveillance with endoscopy after ER for EGC is becoming more important, but how to perform endoscopic surveillance after ER has not been established, even though the follow-up strategy for more advanced gastric cancer has been outlined. Therefore, a surveillance strategy for patients with EGC after ER is needed.

Expressions and clinical significances of c-MET, p-MET and E2f-1 in human gastric carcinoma

Background

To investigate on the expressions and the clinical significances of hepatocyte growth factor receptor (c-MET), phosphorylated c-MET (p-MET) and e2f-1 transcription factor in primary lesion of gastric adenocarcinoma (GC).

Method

Tissue samples from the primary lesion of GC in patients who accepted D₂/D₃ radical gastrectomy with R₀/R₁ resection were stained by immunohistochemistry of c-MET, p-MET, e2f-1 and Ki-67. The univariate and the multivariate analyses involving in clinicopathological parameters and prognostic factors were evaluated.

Results

The positivity rates for c-MET (66.12%, 80 cases/121 cases), p-MET (59.50%, 72 cases/121 cases), e2f-1 (38.84%, 47 cases/121 cases) and Ki-67 (72.73%, 88 cases/121 cases) in primary lesion of GC was significantly higher than that in non-cancerous tissue at 5 cm places far from the margin of primary lesion (P < 0.05, respectively). The deeper tumor invasion, the severer lymph node metastasis, the later stage of TNM and the higher expression of Ki-67 was respectively an independent risk factor for the higher expression of c-MET or p-MET, but the younger age and the shorter survival time was an independent risk factor for the higher expression of e2f-1 respectively. Survival analysis showed that the worse prognosis could be observed in the patients with the combination of both c-MET-positive and e2f-1-negative (P = 0.038) or both p-MET-positive and e2f-1-negative (P = 0.042). Cox analysis demonstrated that the severer lymphatic node metastasis and the higher positivity rate of c-MET, p-MET or e2f-1 were an independent prognosis factor respectively. The higher expression of e2f-1 was identified in patients with Stage I-II, which correlated with a shorter survival time. Survival analysis also revealed that the prognosis of patients with positive expression of e2f-1 at Stage I-II was significantly worse than that in patients with negative expression of e2f-1 (χ² = 13.437, P = 0.001). However, in the cases with Stage III-IV, no significant difference could be identified in the prognostic comparison between positive and negative expressions of e2f-1.

Conclusions

The expression of c-MET or p-MET is an independent prognosis factor. It has been observed that the higher expression of e2f-1 occurred in the early stages while the lower expression of it in the later stages in GC.

Cbl-b enhances sensitivity to 5-fluorouracil via EGFR- and mitochondria-mediated pathways in gastric cancer cells

5-Fluorouracil (5-FU) is an essential component of anticancer chemotherapy against gastric cancer. However, the response rate of single drug is still limited. The ubiquitin ligase Cbl-b is a negative regulator of growth factor receptor signaling and is involved in the suppression of cancer cell proliferation. However, whether Cbl-b could affect 5-FU sensitivity remains unclear. The present study showed that Cbl-b knockdown caused higher proliferation concomitant with the decrease of apoptosis induced by 5-FU treatment in gastric cancer cell. Further mechanism investigation demonstrated that Cbl-b knockdown caused significant increase of phosphorylation of EGFR, ERK and Akt, decrease of mitochondrial membrane potential, and increase of expression ratio of Bcl-2/Bax. These results suggest that Cbl-b enhances sensitivity to 5-FU via EGFR- and mitochondria-mediated pathways in gastric cancer cells.

CMTM3 inhibits cell migration and invasion and correlates with favorable prognosis in gastric cancer

The CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) gene is a novel tumor suppressor with frequent epigenetic inactivation. In this study, we showed the role played by CMTM3 in gastric cancer cells as a tumor suppressor gene, and examined the correlation between CMTM3 expression and clinicopathological parameters using immunohistochemistry in gastric cancer patients with different pathological stages (n = 350). We found that CMTM3 expression was reduced or silenced by epigenetic regulation in gastric cell lines, and dramatically downregulated in primary gastric cancer tissues. Restoration of CMTM3 significantly affected migration and invasion of AGS and SGC-7901 cells (P < 0.001). In vivo experiments showed that peritoneal disseminated metastases were significantly suppressed by CMTM3 (P < 0.001). We further showed that the expression of MMP2 and the phosphorylation of Erk1/2 were decreased when CMTM3 was restored. In addition, by immunohistochemical staining, we found that the expression of CMTM3 was remarkably weaker in gastric cancer tissues than in normal mucosae (P = 0.008), and was significantly correlated with gender (P = 0.033), tumor depth (P = 0.049), stage (P = 0.021), and histological grade (P = 0.022). More importantly, CMTM3 expression was associated with prognosis in gastric cancer patients (P = 0.041), and was a significant independent prognostic indicator (hazard ratio = 0.704, 95% confidence interval, 0.498–0.994; P = 0.046). Our findings indicate that CMTM3 regulates migration and invasion of gastric cancer cells. Moreover, CMTM3 is a candidate marker for prognosis of gastric cancer in the clinic.

The combination of docetaxel, cisplatin, and 5-fluorouracil in advanced gastric cancer: a single-institution experience

The addition of docetaxel to cisplatin and 5-fluorouracil was shown to confer a survival benefit in patients with advanced gastric cancer (one; AGC), although with increased toxicity. We hereby report our experience with the use of docetaxel, cisplatin, and 5-fluorouracil (DCF). Data on all consecutive patients who received first-line treatment with DCF at our institute were analyzed retrospectively. Twenty-three patients were included. The median age was 63 years. Patients received an average of 10 cycles (range, 1-24). All experienced grade ≥3 toxicity, requiring hospitalization in 35%. There was one toxic death. The median progression-free and overall survival rates were 10.0 and 12.8 months, respectively; the 2-year and 3-year survival rates were 22 and 17%, respectively. The DCF regimen is indeed associated with substantial toxicity, although manageable. Nevertheless, the observed benefit was remarkable compared with any previous report on chemotherapy in AGC, and should therefore represent a valid treatment option in AGC and a platform for future combinations.

HER2 in gastric cancer: a digital image analysis in pre-neoplastic, primary and metastatic lesions

The assessment of human epidermal growth factor receptor 2 (HER2) status in gastric cancer is crucial in selecting patients who may benefit from targeted therapy, yet heterogeneous expression could represent an important drawback for HER2 testing. We aimed to analyze (i) HER2 heterogeneity in primary gastric cancers, pre-neoplastic and metastatic lesions and (ii) HER2 prognostic role. We studied 292 surgically resected primary gastric carcinomas and constructed 21 tissue microarrays including tumor tissue cores, invasive front, paired lymph node metastasis, low- and high-grade dysplasia. Microarrays were immunohistochemically stained with HER2 antibody and digitally scanned. Novel digital analysis algorithms were developed to score HER2 expression. Fluorescence in situ hybridization was performed on equivocal cases. HER2-positive cases were 13% and heterogeneous HER2 expression was observed in 71% of positive samples. Analysis of HER2 status in tumor and tumor invasive front demonstrate concordance in 177 cases (88%). Comparison of HER2 expression in primary cancer and synchronous lymph node metastasis exhibited discordant status in 14% of cases. Dysplastic epithelium surrounding the tumor showed immunohistochemical score 2 or 3 in 19% of high-grade and in 9% of low-grade dysplastic samples. HER2 status was significantly associated with intestinal-type carcinomas (P=0.018) and prognosis since patients with primary HER2-positive tumor showed decreased overall survival (P=0.006). Intratumoral HER2 expression heterogeneity and variable lymph node metastases status strongly suggest evaluating more than one sample and, if available, metastatic foci for routinely HER2 testing.

Cytotoxicity of methylsulfonylmethane on gastrointestinal (AGS, HepG2, and KEYSE-30) cancer cell lines

PURPOSE

This study was conducted to assay cytotoxic effects of methylsulfonylmethane (MSM) on gastrointestinal cancer cell lines.

METHODS

Human gastric carcinoma (AGS), human hepatocellular carcinoma (HepG2), and human esophageal squamous cell carcinoma (KYSE-30) cancer cell lines were treated by MSM and incubated for 24, 48, and 72 h. Cytotoxicity was examined through MTT, neutral red uptake, and protein measurement assays. Ethidium bromide/acridine orange (EB/AO) staining was used for apoptotic cell detection. A diamidino-2-phenylindole staining method was used to analysis cell cycle by flow cytometry.

RESULTS

IC(50) of MSM on AGS, HepG2, and KYSE-30 cell lines were 28.04, 21.87 and 27.98 mg/ml after 72 h, respectively. The EB/AO staining showed an increase in apoptotic cells. Cell cycle analysis showed a significant increase in cell density at G2/M phase.

CONCLUSION

MSM had cytotoxic effect on cancer cell lines but HepG2 cell line was more susceptible. This study suggests that MSM may induce cytotoxic effect on gastrointestinal cancer cell lines by apoptosis and cell cycle arrest.

Suppressive effects of an ethanol extract of Gleditsia sinensis thorns on human SNU-5 gastric cancer cells

The thorns of Gleditsia sinensis are a traditional Oriental medicine used for the treatment of swelling, suppuration, carbuncle and skin diseases. In the present study, we identified a novel molecular mechanism by which an ethanol extract of Gleditsia sinensis thorns (EEGS) inhibits the growth of the SNU-5 human gastric cancer cell line. EEGS treatment inhibited cell growth and was associated with G1 phase cell cycle arrest at a concentration of 400 µg/ml (IC50) in SNU-5 cells. Treatment with EEGS also stimulated p21WAF1 expression, which significantly decreased the expression of cyclins and cyclin-dependent kinases (CDKs). Further study suggested that p38 MAP kinase pathways may be involved in the inhibition of cell proliferation through p21WAF1‑dependent G1 phase cell cycle arrest in EEGS-treated cells. In addition, NF-κB and AP-1 transcription factor binding sites were identified as the cis-elements for tumor necrosis factor-α (TNF-α)-induced matrix metalloproteinase-9 (MMP-9) expression in SNU-5 cells, as determined by gel-shift assay. Treatment of cells with EEGS suppressed MMP-9 expression induced by TNF-α via a decrease in the binding activity of both NF-κB and AP-1 motifs. These data demonstrate that EEGS-mediated inhibition of cell growth appears to involve the activation of p38 MAP kinase, subsequently leading to the induction of p21WAF1 and the downregulation of cyclin D1/CDK4 and cyclin E/CDK2 complexes. Moreover, EEGS strongly inhibited TNF-α-induced MMP-9 expression by impeding the DNA binding activity of NF-κB and AP-1. Overall, these results provide a potential mechanism for EEGS in the treatment of gastric cancer.

Differential susceptibility of gastric cancer cells to TRAIL-induced apoptosis

Understanding the molecular basis of the differential sensitivity of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis is required to predict therapeutic outcomes and to improve the effectiveness of TRAIL-based therapy. This study aimed to compare the responsiveness of gastric cancer cells to TRAIL treatment and to investigate the molecular basis of the differential TRAIL sensitivity of four gastric cancer cell lines. The TRAIL sensitivity of the four cell lines was ranked in the following order: SNU-16 ≈ SNU-620 > SNU-5 >> SNU-1. The level of Annexin V binding and the activation profile of caspase-3, -8 and -9 corroborated the differential TRAIL susceptibility of the cell lines. To determine the molecular basis of the differential sensitivity to TRAIL, we examined the expression of signaling components involved in TRAIL-mediated apoptosis. The mRNA level and surface expression of death receptor 4 (DR4) were significantly decreased in the SNU-1 cells compared to the other cell lines. Bid cleavage and X-linked inhibitor of apoptosis (XIAP) degradation were significantly increased in the SNU-16 and SNU-620 cells compared to the SNU-5 and SNU-1 cells, although Bid and XIAP were expressed at similar levels across the four cell lines. The expression and degradation of FLICE-inhibitory protein (FLIP) upon TRAIL treatment was independent of TRAIL sensitivity. In conclusion, the differential susceptibility of the four gastric cancer cells to TRAIL may be ascribed to the differential expression of DR4 and the proper augmentation of the death signal by the truncation of Bid and degradation of XIAP.

Current questions for the treatment of advanced gastric cancer

BACKGROUND

Gastric cancer remains a major health problem worldwide. Treatment of advanced gastric cancer is controversial and there is no standard regimen for first- or second-line chemotherapy (CT). This review aims to give an overview of the hot topics concerning treatment, prognostic factors and new strategies in advanced gastric cancer.

MATERIAL AND METHODS

Seven questions of special clinical interest have been formulated previously to the literature review. With the aim of answering each of these questions, a specific search of the relevant trials and meta-analyses published or communicated from 1990 to date was performed.

RESULTS

Patients treated with CT have a survival benefit over those treated with only best supportive care (BSC). Such active cytotoxic drugs as cisplatin or docetaxel and targeted agents as trastuzumab showed superiority in randomized trials. Other agents such as oxaliplatin, oral fluoropyrimidines and irinotecan showed non-inferiority or less toxic results, positioning them as valuable alternatives to classical schedules. Combination regimens seem to be an improvement over single agent therapy. However, increased toxicity of some regimens makes their general use difficult. Second-line CT is of value for selected patients with good performance status. Trastuzumab is the only targeted agent showing better survival when added to chemotherapy in HER2-driven tumors.

CONCLUSIONS

With the introduction of new agents, management of advanced gastric cancer has experienced important changes. First and second-line CT improve survival in patients with good performance status. Future trials should address how to better select patients for new, targeted agents, based upon validated predictive biomarkers.

FKBP5 polymorphisms as vulnerability to anxiety and depression in patients with advanced gastric cancer: a controlled and prospective study

Cancer patients, who have to adapt to a long treatment process with multiple stressful events, show various stress responses. Genetic components may contribute to individual differences in stress response and risk for development of stress-related psychiatric problems. The present study aimed to investigate the influence of FK506 binding protein 5 (FKBP5) gene polymorphisms regulating the hypothalamic-pituitary-adrenal (HPA) axis on individual distress levels in cancer patients faced with similar stressful situation. The present study used a prospective design to elucidate predictors of distress. A total of 130 patients (90 males, 40 females) who were newly diagnosed with advanced gastric cancer and supposed to receive first-line chemotherapy were initially assessed, and a six-week follow-up assessment occurred for 93 patients (63 males, 30 females) after two cycles of chemotherapy. Distress levels and coping patterns were measured by the Hospital Anxiety and Depression Scale (HADS) and Mini-Mental Adjustment to Cancer (Mini-MAC) scale. For genetic factors, three single nucleotide polymorphisms of FKBP5 rs1360780, rs9296158 and rs9470080 were genotyped. For HADS-anxiety, FKBP5 rs9296158 had a significant group-by-time interaction (p=0.015), and rs9470080 and rs1360780 had a marginally significant interaction (p=0.023, p=0.038, respectively). For HADS-depression, rs9470080 and rs9296158 had a marginally significant group-by-time interaction (p=0.026, p=0.032, respectively). In addition, a step-wise linear regression analysis showed that FKBP5 rs9470080 and rs9296158 were significant predictors of anxiety and depression after prolonged stress exposure in cancer patients. Our findings indicate that the genetic factors regulating the HPA axis such as FKBP5 gene polymorphisms may play a crucial role in anxiety and depression following prolonged stress exposure.

Differential protein expression in EC304 gastric cancer cells induced by alphastatin

OBJECTIVE

To explore the differential protein expression profile in EC304 gastric cancer cells induced by alphastatin.

METHODS

Cultured EC304 cells in the exponential phase of growth were randomly divided into alphastatin and control groups. Total proteins were extracted and the two dimensional electrophoresis (2-DE) technique was applied to analyze differences in expression with ImageMaster 2D Platinum 5.0 software. Proteins were identified using the MASCOT database and selected differently expressed proteins were characterised by western blotting and immunofluorescence.

RESULTS

1350 ± 90 protein spots were detected by the ImageMaster software in the 2-DE gel images from the control and alphastatin groups. The match rate was about 72-80% for the spectrum profiles, with 29 significantly different protein spots being identified, 10 upregulated, 16 downregulated, two new and one lost. The MASCOT search scores were 64-666 and the peptide matching numbers were 3-27 with sequence coverage of 8-62%. Twenty-three proteins were checked by mass spectrometry, including decrease in Nm23 and profilin-2 isoform b associated with the regulation of actin multimerisation induced by extracellular signals.

CONCLUSION

The proteome in EC304 cells is dramatically altered by alphastatin, which appears to play an important role in modulating cellular activity and anti-angiogenesis by regulating protein expression and signal transduction pathways through Nm23 and profilin-2 isoform b, providing new research directions for anti-angiogenic therapy of gastric cancer.

[Comparison of the toxicities and efficacies of the combination chemotherapy regimens in advanced gastric cancer patients who achieved complete response after chemotherapy]

BACKGROUND/AIMS

We retrospectively analyzed comparative toxicities and efficacies of chemotherapy regimens in advanced gastric cancer (AGC) patients who achieved complete response (CR) after chemotherapy.

METHODS

We reviewed the medical records of 1,203 patients, who were pathologically diagnosed as AGC in a single center between January 2001 and October 2007. On the basis of the Response Evaluation Criteria in Solid Tumors, CR was evaluated with abdominal computed tomography. Toxicities were evaluated using the National Cancer Institute's common toxicity criteria before each chemotherapy cycle.

RESULTS

Among the 1,203 AGC patients enrolled in this study, 568 received chemotherapy and 635 received best supportive care. The major chemotherapy regimens were 5-fluorouracil, leucovorin and oxaliplatin (FOLFOX), docetaxel, cisplatin and 5-fluorouracil (DCF) and 5-fluorouracil, leucovorin and irinotecan (FOLFIRI). Among the 568 patients, 51 (9.0%) achieved CR (49 [8.6%] with FOLFOX [n=12], DCF [n=26], or FOLFIRI [n=11] and 2 [0.3%] with etoposide, leucovorin and 5-fluorouracil). For patients administered FOLFOX, DCF, and FOLFIRI, the median time to disease progression was 4 months (range, 1.8-59.5), 15 months (range, 2.9-31.2) and 10 months (range, 2.0-39.5), and the median survival times were 48 months (range, 5.9-74.0), 37 months (range, 14.0-86.0), and 30 months (range, 6.0-50.0), respectively. Grades 3-4 mucositis occurred mostly in patients administered DCF (n=8, 30.8%). Grades 3-4 leucopenia were observed in 1 (8.3%), 11 (42.3%), and 4 (36.4%) patients administered FOLFOX, DCF and FOLFIRI, respectively. No statistically significant differences were observed in the 3 regimens.

CONCLUSIONS

All 3 regimens (FOLFOX, DCF and FOLFIRI) were active and tolerable. Their efficacies and toxicities were not significantly different.

Treatment strategy for gastric non-invasive intraepithelial neoplasia diagnosed by endoscopic biopsy

Treatment strategies, whether as follow-up or “total incisional biopsy” for gastric noninvasive intraepithelial neoplasia diagnosed by examination of an endoscopic forceps biopsy specimen, are controversial due to problems associated with the diagnostic accuracy of endoscopic forceps biopsy and questions about the safety and efficacy of endoscopic treatment. Based on the histological findings of the biopsy specimen, it is difficult to differentiate between reactive or regenerative changes, inflammation and neoplastic changes, intraepithelial and invasive tumors. Therefore, gastric neoplasia diagnosed as noninvasive intraepithelial often develop into invasive carcinoma during follow-up. Recent advances in endoscopic modalities and treatment devices, such as image-enhanced endoscopy and high-frequency generators, may make endoscopic treatment, such as endoscopic submucosal dissection (ESD), a therapeutic option for gastric intraepithelial neoplasia, including low-grade neoplasms. Future studies are required to evaluate whether ESD is a valid strategy for gastric intraepithelial neoplasm with regard to safety and cost effectiveness.

Efficacy of pre-operative chemotherapy with docetaxel, cisplatin, and S-1 (DCS therapy) and curative resection for gastric cancer with pathologically positive para-aortic lymph nodes

BACKGROUND

The prognosis of gastric cancer with para-aortic lymph node (PAN) metastasis is poor. We applied triple combination chemotherapy with docetaxel, cisplatin, and S-1 (DCS therapy) as pre-operative chemotherapy and investigated the outcome of the combination of this therapy and gastrectomy with para-aortic lymph node dissection (PAND).

METHODS

We retrospectively identified 44 patients with pathologically positive PAN who underwent curative surgery at Kanazawa University Hospital between 1990 and 2008. Among the 44 patients, 16 received pre-operative DCS therapy and subsequent surgical resection after two courses of the therapy.

RESULTS

Pre-operative DCS therapy showed high clinical response ratio (68.8%) and disease control ratio (100%). The pathological response ratio of resected specimen was 87.5%. At 2 years after surgery, the overall survival ratio was 93.8% and relapse-free survival was 75.0%. Pre-operative DCS therapy was only independent prognostic factor in multivariate analysis. Grade 3/4 toxicity was observed only in 25.0% of patients who underwent DCS therapy. Surgical complication was observed in 31.3% of patients, and this ratio was equal to that of patients who did not receive DCS therapy.

CONCLUSION

Multimodal therapy comprising combined pre-operative DCS therapy and gastrectomy with PAND was extremely effective and feasible for advanced gastric cancer with PAN metastasis.

F18-fluorodeoxyglucose-positron emission tomography and computed tomography is not accurate in preoperative staging of gastric cancer

PURPOSE

To investigate the clinical benefits of F18-fluorodeoxyglucose-positron emission tomography and computed tomography ((18)F-FDG-PET/CT) over multi-detector row CT (MDCT) in preoperative staging of gastric cancer.

METHODS

FDG-PET/CT and MDCT were performed on 78 patients with gastric cancer pathologically diagnosed by endoscopy. The accuracy of radiologic staging retrospectively was compared to pathologic result after curative resection.

RESULTS

Primary tumors were detected in 51 (65.4%) patients with (18)F-FDG-PET/CT, and 47 (60.3%) patients with MDCT. Regarding detection of lymph node metastasis, the sensitivity of FDG-PET/CT was 51.5% with an accuracy of 71.8%, whereas those of MDCT were 69.7% and 69.2%, respectively. The sensitivity of (18)F-FDG-PET/CT for a primary tumor with signet ring cell carcinoma was lower than that of (18)F-FDG-PET/CT for a primary tumor with non-signet ring cell carcinoma (35.3% vs. 73.8%, P < 0.01).

CONCLUSION

Due to its low sensitivity, (18)F-FDG-PET/CT alone shows no definite clinical benefit for prediction of lymph node metastasis in preoperative staging of gastric cancer.