Expression of AFP and STAT3 is involved in arsenic trioxide-induced apoptosis and inhibition of proliferation in AFP-producing gastric cancer cells

Unraveling the genetics of arsenic toxicity with cellular morphology QTL

The health risks that arise from environmental exposures vary widely within and across human populations, and these differences are largely determined by genetic variation and gene-by-environment (gene-environment) interactions. However, risk assessment in laboratory mice typically involves isogenic strains and therefore, does not account for these known genetic effects. In this context, genetically heterogenous cell lines from laboratory mice are promising tools for population-based screening because they provide a way to introduce genetic variation in risk assessment without increasing animal use. Cell lines from genetic reference populations of laboratory mice offer genetic diversity, power for genetic mapping, and potentially, predictive value for in vivo experimentation in genetically matched individuals. To explore this further, we derived a panel of fibroblast lines from a genetic reference population of laboratory mice (the Diversity Outbred, DO). We then used high-content imaging to capture hundreds of cell morphology traits in cells exposed to the oxidative stress-inducing arsenic metabolite monomethylarsonous acid (MMAIII). We employed dose-response modeling to capture latent parameters of response and we then used these parameters to identify several hundred cell morphology quantitative trait loci (cmQTL). Response cmQTL encompass genes with established associations with cellular responses to arsenic exposure, including Abcc4 and Txnrd1, as well as novel gene candidates like Xrcc2. Moreover, baseline trait cmQTL highlight the influence of natural variation on fundamental aspects of nuclear morphology. We show that the natural variants influencing response include both coding and non-coding variation, and that cmQTL haplotypes can be used to predict response in orthogonal cell lines. Our study sheds light on the major molecular initiating events of oxidative stress that are under genetic regulation, including the NRF2-mediated antioxidant response, cellular detoxification pathways, DNA damage repair response, and cell death trajectories.

Cell morphology QTL reveal gene by environment interactions in a genetically diverse cell population

Genetically heterogenous cell lines from laboratory mice are promising tools for population-based screening as they offer power for genetic mapping, and potentially, predictive value for in vivo experimentation in genetically matched individuals. To explore this further, we derived a panel of fibroblast lines from a genetic reference population of laboratory mice (the Diversity Outbred, DO). We then used high-content imaging to capture hundreds of cell morphology traits in cells exposed to the oxidative stress-inducing arsenic metabolite monomethylarsonous acid (MMAIII). We employed dose-response modeling to capture latent parameters of response and we then used these parameters to identify several hundred cell morphology quantitative trait loci (cmQTL). Response cmQTL encompass genes with established associations with cellular responses to arsenic exposure, including Abcc4 and Txnrd1, as well as novel gene candidates like Xrcc2. Moreover, baseline trait cmQTL highlight the influence of natural variation on fundamental aspects of nuclear morphology. We show that the natural variants influencing response include both coding and non-coding variation, and that cmQTL haplotypes can be used to predict response in orthogonal cell lines. Our study sheds light on the major molecular initiating events of oxidative stress that are under genetic regulation, including the NRF2-mediated antioxidant response, cellular detoxification pathways, DNA damage repair response, and cell death trajectories.

Novel Histopathological Biomarkers in Prostate Cancer: Implications and Perspectives

Prostate cancer (PCa) is the second most frequently diagnosed cancer in men. Despite the significant progress in cancer diagnosis and treatment over the last few years, the approach to disease detection and therapy still does not include histopathological biomarkers. The dissemination of PCa is strictly related to the creation of a premetastatic niche, which can be detected by altered levels of specific biomarkers. To date, the risk factors for biochemical recurrence include lymph node status, prostate-specific antigen (PSA), PSA density (PSAD), body mass index (BMI), pathological Gleason score, seminal vesicle invasion, extraprostatic extension, and intraductal carcinoma. In the future, biomarkers might represent another prognostic factor, as discussed in many studies. In this review, we focus on histopathological biomarkers (particularly CD169 macrophages, neuropilin-1, cofilin-1, interleukin-17, signal transducer and activator of transcription protein 3 (STAT3), LIM domain kinase 1 (LIMK1), CD15, AMACR, prostate-specific membrane antigen (PSMA), Appl1, Sortilin, Syndecan-1, and p63) and their potential application in decision making regarding the prognosis and treatment of PCa patients. We refer to studies that found a correlation between the levels of biomarkers and tumor characteristics as well as clinical outcomes. We also hypothesize about the potential use of histopathological markers as a target for novel immunotherapeutic drugs or targeted radionuclide therapy, which may be used as adjuvant therapy in the future.

Breast tumor metastasis following filgrastim administration due to the SDF-1/CXCR4 pathway

Filgrastim, a recombinant type of granulocyte-colony stimulating factor (G-CSF), has a high potential to manage chemotherapy-induced leukopenia. It can increase stromal cell-derived factor 1 (SDF-1) which may stimulate C-X-C chemokine receptor type 4 (CXCR4) to migrate bone marrow-derived stem/progenitor cells to the bloodstream. Here, we aimed to investigate in vitro and in vivo effects of filgrastim on cell migration, invasion, and metastasis. A lentivirus vector of the anti-CXCR4 receptor was first used for the CXCR4 knockout. Effects of filgrastim on cell proliferation and migration were then investigated on 4T1 cells by Transwell migration and wound healing assay. At last, the effects of filgrastim on cell metastasis and the possible involved mechanisms have been investigated in a metastatic murine breast tumor. The knockout of the CXCR4 receptor could lead to a decrease in cell proliferation, migration, and invasion of the 4T1 cells. Filgrastim could directly target SDF-1 and upregulate the expression of the CXCR4 receptor. The knockout of the CXCR4 receptor reduced cell metastasis in an animal model of breast cancer. CXCR4 receptor stimulation by the filgrastim-affected pathways is a conserved evolutionary response that could increase cancer cell proliferation and consequent cell metastasis. Our results suggest that the activation of the CXCR4 receptor is a conserved evolutionary response that can increase cell proliferation, migration, and consequent metastasis. It seems that filgrastim may increase the chance of cancer cell metastasis in people continuously receiving it to increase the number of neutrophils. Filgrastim induces the SDF-1/CXCR4 axis on tumor cell growth. SDF-1 and its receptor CXCR4 are vital targets for filgrastim. The CXCR4 can stimulate the PI3K/AKT, NF-κB, and JAK/STAT signaling pathways. The SDF-1/CXCR4 pathway promotes cell chemotaxis and proliferation via MAPKs signaling. It also enhances cell survival, proliferation, and angiogenesis, increasing tumor cell metastasis. The STAT3-mediated inflammation is essential for tumorigenesis processes, and Akt, Wnt, STAT3, and CXCR4 signaling pathways are all correlated. CXCR4 = C-X-C chemokine receptor type 4, SDF-1 = stromal-derived-factor-1, MAPK = mitogen activated protein kinase; NF-κB = nuclear factor-κB, PI3K = phosphoinositide 3-kinase, JAK = Janus kinase, STAT = signal transducer and activator of transcription, PLC = phospholipase C, PKC = Protein kinase C, GRK = G protein-coupled receptor kinase.

Arsenic Trioxide Affects the Proliferation of Gastric Cancer Cells through MiR-885-5p/CDC73 Axis

Background

To explore Arsenic trioxide (As₂O₃) and its regulated miR-885-5p/CDC73 signaling pathway involved in the development of gastric cancer.

Methods

Fifty-two healthy patients and patients with gastric cancer were enrolled 2019-2020 in He Xian Memorial Hospital, Guangzhou, China. The patients with gastric cancer were divided into control group and As₂O₃ administration group. After 2 courses of treatment, their peripheral blood was collected to analyze the therapeutic effect. miR-885-5p expression in peripheral blood was analyzed by qRT-PCR. As₂O₃ was added into MGC-803 gastric cancer cell line at 0, 10, 20, 40 and 80 μmol/L. The proliferation rate and 48h IC50 value of gastric cancer cells were investigated by CCK-8, and the effect of As2O3 on miR-885-5p expression in the cells was analyzed.

Results

After 4 weeks of treatment, the objective efficiency of control group and As₂O₃ administration group was 17.3% and 13.4%, respectively, without significant statistical difference. The overall benefit rate of As₂O₃ administration group was significantly higher than that of the normal treatment group (P=0.049). qRT-PCR experiment results found that miR-885-5p significantly highly expressed in peripheral blood in the As₂O₃ administration group, while miR-885-5p in gastric cancer was lower compared with normal people. Adding As₂O₃ to the gastric cancer cells could significantly inhibit miR-885-5p expression, while miR-885-5p in gastric cancer cells affected cell expression by targeted regulation, affecting cell proliferation.

Conclusion

As₂O₃ may be used as a drug treatment program for gastric cancer, and mainly regulates the proliferation of gastric cancer cells by affecting the miR-885-5p/CDC73 target axis to participate in the development of gastric cancer.

Case report: Significant response to PD-L1 inhibitor after resistance to PD-1 inhibitor in an advanced alpha-fetoprotein-positive gastric cancer

Alpha-fetoprotein-positive gastric cancer (AFPGC) is a type of gastric cancer with a high degree of malignancy. The disease is more common in the elderly, with a high prevalence in males and generally atypical clinical manifestations. For advanced patients, the current treatment options are limited and, to date, few cases of advanced AFPGC have been treated successfully with conventional chemotherapy. With the development of molecular biology and immunology, tumor immunotherapy offers more therapeutic options to patients with advanced gastric cancer. This study describes a case of advanced gastric cancer in a young woman with a high blood alpha-fetoprotein (AFP) level (>54,000 ng/mL). The patient showed initial promising results when programmed cell death-1 (PD-1) inhibitor treatment was combined with chemotherapy after systemic chemotherapy failed. When the disease progressed again after 129 days, adjustment of the treatment regimen to Atezolizumab in combination with Irinotecan and Surufatinib capsules achieved partial remission (PR). There were no immune-related pneumonia, myocarditis, or other adverse effects observed. The patient currently has an overall survival of more than 14 months. This case demonstrated that switching from PD-1 inhibitor to programmed cell death-Ligand 1 (PD-L1) inhibitor therapy may overcome potential resistance. It providing a reference for immunotherapy of patients with AFP-positive advanced gastric cancer.

Novel Mechanistic Insights into the Anti-cancer Mode of Arsenic Trioxide

Arsenic, a naturally-occurring toxic element, and a traditionally-used drug, has received a great deal of attention worldwide due to its curative anti-cancer properties in patients with acute promyelocytic leukemia. Among the arsenicals, arsenic trioxide has been most widely used as an anti-cancer drug. Recent advances in cancer therapeutics have led to a paradigm shift away from traditional cytotoxic drugs towards the targeting of proteins closely associated with driving the cancer phenotype. Due to the diverse anti-cancer effects of ATO on different types of malignancies, numerous studies have made efforts to uncover the mechanisms of ATO-induced tumor suppression. From in vitro cellular models to studies in clinical settings, ATO has been extensively studied. The outcomes of these studies have opened doors to establishing improved molecular-targeted therapies for cancer treatment. The efficacy of ATO has been augmented by combination with other drugs. In this review, we discuss recent arsenic-based cancer therapies and summarize the novel underlying molecular mechanisms of the anti-cancer effects of ATO.

A 50-Year-Old Man with Fulminant Alpha-Fetoprotein-Producing Gastric Carcinoma and Disseminated Intravascular Coagulation

Patient: Male, 50-year-old

Final Diagnosis: Disseminated intravascular coagulatio • gastric cancer

Symptoms: Paralysis

Medication: —

Clinical Procedure: —

Specialty: Oncology

Prognostic values of signal transducers activators of transcription in gastric cancer

The signal transducers and activators of transcription genes family (STATs) have been well studied as prognostic predictors for various solid tumors, but their prognostic values in gastric cancer (GC) patients have not been fully elucidated. The 'Kaplan-Meier plotter' and multiple public available databases were used for the characterization of the prognostic roles of STATs family in GC. The results indicated that high mRNA expression of all individual STATs, except STAT3 and STAT6, were significantly associated with favorable overall survival (OS) in GC. Moreover, the prognostic values of STATs were further characterized in subtypes, including HER2 status, Lauren's classification, differentiation, and clinical stages. Moreover, the prognostic value of STATs signature was also characterized. Low risk group displayed a significantly favorable OS than high risk (HR: 1.71; 95% CI: 1.09-2.66, P=0.0184). In addition, STATs showed distinct expression between GC and normal groups. Meanwhile, comparable high correlation between STATs and tumor immune infiltrating cells (TIICs) was also observed. STAT4 displayed highest correlation with dendritic cells (correlation = 0.716, P=1.63e-59) and CD8⁺ T cells (correlation = 0.697, P=5.02e-55). In conclusion, our results suggest that all individual STATs, except STAT3 and STAT6, may act as prognostic markers in GC.

Clinicopathological significance and prognostic role of p-STAT3 in patients with hepatocellular carcinoma

Background and aim

Constitutive activation of STAT3 through its phosphorylation (p-STAT3) plays a key role in the development and progression of various cancers. However, the relationship between p-STAT3 expression and the clinicopathological features and prognostic value in patients with hepatocellular carcinoma (HCC) remains controversial. We conducted a meta-analysis to evaluate the role of p-STAT3 in HCC.

Methods

The PubMed, Cochrane Library, Web of Science, EMBASE, Chinese CNKI, and Chinese Wanfang databases were searched using the appropriate terms to find the relevant studies on p-STAT3 and HCC. The relationship between p-STAT3 expression and clinicopathological characteristics and prognostic value was established. Pool odds ratios (ORs) and hazard ratios (HRs) with 95% CIs were calculated using the STATA 14.2 software.

Results

The eight articles included in this meta-analysis comprised 752 patients. Expression of p-STAT3 was associated with incidence, age, liver cirrhosis, tumor size, vascular invasion, and TNM stage of HCC, but it was not related to gender, alpha-fetoprotein (AFP), hepatitis B surface antigen (HBsAg), number of tumors, and tumor differentiation. Additionally, the expression of p-STAT3 was related to a poor 3- and 5-year overall survival rate and disease-free survival rate.

Conclusion

Expression of p-STAT3 was associated with the incidence, age, liver cirrhosis, tumor size, vascular invasion, and TNM stage. Thus, p-STAT3 can be a reliable prognostic biomarker for HCC. Further high-quality studies with larger numbers of patients are needed.

Arsenic trioxide attenuates STAT-3 activity and epithelial-mesenchymal transition through induction of SHP-1 in gastric cancer cells

BACKGROUND

We investigated the effect of arsenic trioxide (ATO) for inhibition of signal transducer and activator of transcription 3 (STAT3) and epithelial-mesenchymal transition (EMT) in gastric cancer cells, and the role of SH2 domain-containing phosphatase-1 (SHP-1) during this process.

METHODS

We used AGS cells, which showed minimal SHP-1 expression and constitutive STAT3 expression. After treatment of ATO, cellular migration and invasion were assessed by using wound closure assay, Matrigel invasion assay and 3-D culture invasion assay. To validate the role of SHP-1, pervanadate, a pharmacologic phosphatase inhibitor, and SHP-1 siRNA were used. Xenograft tumors were produced, and ATO or pervanadate were administered via intraperitoneal (IP) route.

RESULTS

Treatment of ATO 5 and 10 μM significantly decreased cellular migration and invasion in a dose-dependent manner. Western blot showed that ATO upregulated SHP-1 expression and downregulated STAT3 expression, and immunofluorescence showed upregulation with E-cadherin (epithelial marker) and downregulation of Snail1 (mesenchymal marker) expression by ATO treatment. Anti-migration and invasion effect and modulation of SHP-1/STAT3 axis by ATO were attenuated by pervanadate or SHP-1 siRNA. IP injection of ATO significantly decreased the xenograft tumor volume and upregulated SHP-1 expression, which were attenuated by co-IP injection of pervanadate.

CONCLUSION

Our data suggest that ATO inhibits STAT3 activity and EMT process by upregulation of SHP-1 in gastric cancer cells.

Prognostic role of STAT3 in solid tumors: a systematic review and meta-analysis

Accumulated studies have provided controversial evidences of the association between signal transducer and activator of transcription proteins 3 (STAT3) expression and survival of human solid tumors. To address this inconsistency, we performed a meta-analysis with 63 studies identified from PubMed, Medline and EBSCO. We found STAT3 overexpression was significantly associated with worse 3-year overall survival (OS) (OR = 2.06, 95% CI = 1.57 to 2.71, P < 0.00001) and 5-year OS (OR = 2.00, 95% CI = 1.53 to 2.63, P < 0.00001) of human solid tumors. Similar results were observed when disease free survival (DFS) were analyzed. Subgroup analysis showed that elevated STAT3 expression was associated with poor prognosis of gastric cancer, lung cancer, gliomas, hepatic cancer, osteosarcoma, prostate cancer, pancreatic cancer but better prognosis of breast cancer. The correlation between STAT3 and survival of solid tumors was related to its phosphorylated state. High expression level of STAT3 was also associated with advanced tumor stage. In conclusion, elevated STAT3 expression is associated with poor survival in most solid tumors. STAT3 is a valuable biomarker for prognosis prediction and a promising therapeutic target in human solid tumors.

Efficacy and safety of SOX chemotherapy with or without surgery in AFP-producing advanced gastric cancer

The present study investigated the clinical efficacy of S-1 plus oxaliplatin (SOX) regimen, with or without surgery in α-fetoprotein-producing gastric cancer (APGC) with liver metastasis. A total of 24 patients with APGC treated at the Liaocheng People's Hospital between January 2011 and December 2013 were retrospectively reviewed. Clinical efficacy and patient safety were compared between the two groups. The median progression-free survival (PFS) and overall survival (OS) in the SOX group were 6.5 [95% confidence interval (CI), 4.6–8.4] and 13.5 (95% CI, 8.1–18.9) months, respectively. The corresponding indicators in the SOX and surgery group were 7.0 (95% CI, 5.7–8.3) and 14 (95% CI, 11.0–17.1) months, respectively. There was no significant difference in PFS and OS between the two groups (P=0.703 and 0.710, respectively). The adverse effects of leucopenia, neutropenia, anemia and diarrhea occurred in ~10% of patients in the SOX group and in 14.3% (2/14), 7.14% (1/14), 14.3% (2/14) and 7.14% (1/14), respectively, in the surgery group. No significant difference was identified between groups in terms of overall incidence of adverse effects (P=0.17). However, severe adverse events, including gastroplegia, pancreatic fistula, pulmonary infection and refractory ascites, occurred only in the SOX plus surgery group [incidence rate for severe adverse events, 7.14% (1/14); P<0.001 between groups]. In conclusion, SOX chemotherapy is safe and effective in patients with APGC and liver metastasis. However, the addition of surgery to SOX chemotherapy may not improve the disease control rate and may increase the adverse effects.

Protein profiling of alpha-fetoprotein producing gastric adenocarcinoma

Alpha-fetoprotein (AFP) producing gastric adenocarcinoma is considered as a rare subtype of gastric adenocarcinoma. Compared with AFP non-producing gastric adenocarcinoma, our study and other previous studies showed that AFP producing gastric adenocarcinoma is more aggressive and prone to liver metastasis. Using the Protein Pathway Array, 11 of out of 286 proteins tested were found to be differentially expressed between AFP producing (n=32) and AFP non-producing (n=45) gastric adenocarcinoma tissues. In addition, the high level expression of XIAP and IGF-Irβ in gastric adenocarcinoma tissues was independent factors for poor prognosis in AFP producing gastric adenocarcinoma patients. A risk model based on the XIAP and IGF-Irβ expression levels can separate AFP producing gastric adenocarcinoma patients into 2 subgroups and each subgroup had a distinct set of signaling pathways involved. In conclusion, AFP producing gastric adenocarcinoma is a heterogeneous cancer with different clinical outcomes, biological behaviors and underlying molecular alterations.

Epigenetic regulation and anti-tumorigenic effects of SH2-containing protein tyrosine phosphatase 1 (SHP1) in human gastric cancer cells

SH2-containing protein tyrosine phosphatase 1 (SHP1) is an important negative regulator in cytokine-mediated signal transduction and cell cycling. Recent studies have demonstrated that SHP1 promoter methylation is frequently observed in gastric adenocarcinoma tissues. In this in vitro study, we attempted to reveal promoter hypermethylation and to investigate effects of SHP1 in gastric carcinoma cell lines. We observed that both gene and protein expression of SHP1 were negative in 8 of 10 gastric cancer cell lines (SNU-1, SNU-5, SNU-16, SNU-638, SNU-719, MKN-28, MKN-45, AGS). Methylation-specific PCR (MSP) showed a methylation-specific band only in the 10 gastric cancer lines. Bisulfite pyrosequencing in AGS, MKN-28, and SNU-719 cells indicated that methylation frequency was as high as 94.4, 92.6, and 94.5 %, respectively, in the three cell lines. Treatment of SNU-719, MKN-28, and AGS cells with 5-Aza-2'-deoxycytidine (5-Aza-dc) led to re-expression of SHP1 in these cells. Introduction of exogenous SHP1 in SNU-719 and MKN-28 cells by transient transfection substantially downregulated protein expression of constitutive phosphor-Janus kinase 2 (JAK2) (tyrosine 1007/1008) and phosphor-signal transducers and activators of transcription 3 (STAT3) (tyrosine 705), which in turn decreased expression of STAT3 target genes including those encoding cyclin D1, MMP-9, VEGF-1, and survivin. Induction of SHP1 significantly inhibited cell proliferation, migration and invasion in SNU-719 and MKN-28 cells. Taken together, epigenetic silencing of SHP1 is frequently caused by promoter hypermethylation in gastric carcinoma cells. Overexpression of SHP1 downregulates the JAK2/STAT3 pathway to modulate various target genes and inhibit cell proliferation, migration, and invasion in gastric cancer cells.

Prognostic significance of STAT3/phosphorylated-STAT3 in tumor: a meta-analysis of literatures

PURPOSE

The prognostic value of the expression of STAT3/phosphorylated-STAT3 on survival for cancer patients remains controversial. We performed a meta-analysis of the published literature in this field to identify its impact.

METHODS

We conducted a meta-analysis of 26 studies (n=3877 patients) that evaluated the relationship between the prognostic value and the expression of STAT3/phosphorylated-STAT3 in 15 different kinds of carcinomas. Studies evaluated the correlation between STAT3/phosphorylated-STAT3, which detected mostly by immunohistochemistry and western blot, and clinical staging, overall survival (OS) and disease free survival (DFS) were included. The impact of STAT3 and phosphorylated-STAT3 was analyzed separately.

RESULTS

A total of 26 studies (14 for STAT3 and 16 for phosphorylated-STAT3), comprising 3877 patients, were included for meta-analysis. The expression of STAT3 was strongly associated with a poor impact on overall survival (OS) in all eligible studies [hazard ratio (HR)=2.91, (95% confidence interval (CI), 1.91-4.42)], while a significant association was shown between the expression of phosphorylated-STAT3 and patients' outcome [HR=1.53, (95% CI, 0.86-2.70)]. No significant effect was shown between the expression of STAT3/phosphorylated-STAT3 and clinical staging, neither with DFS.

CONCLUSION

High expression of STAT3 seems to be associated with poor OS in patients with carcinomas, while phosphorylated-STAT3 does not.

Antitumorigenic effect of plumbagin by induction of SH2-containing protein tyrosine phosphatase 1 in human gastric cancer cells

A recent study reported that plumbagin downregulated the activity of Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) pathway to show various antitumor effects in multiple myeloma cells. We aimed in this in vitro study to demonstrate the inhibition of JAK2/STAT3 pathway by plumbagin through inducing SH2-containing protein tyrosine phosphatase 1 (SHP1) expression in the MKN-28 gastric cancer cell line. We performed western blot analysis to measure SHP1, phosphor-JAK2/STAT3 level, and observed that plumbagin induced SHP1 expression and simultaneously downregulated phosphor-JAK2/STAT3 in MKN-28 cells, with negative SHP1 expression. This effect was consistent when JAK2/STAT3 signaling was activated by interleukin-6 (IL-6), and ameliorated when cells were treated with prevanadate, a protein tyrosin phosphatase inhibitor. Furthermore, plumbagin significantly reduced gene expression of cyclin D1, vascular endothelial growth factor (VEGF)-1, Bcl-xL, survivin and matrix metalloproteinase-9 (MMP-9), known target products of STAT3 activation in gastric carcinogenesis by reverse transcription-polymerase chain reaction (RT-PCR). Several functional studies such as water soluble tetrazolium salt-1 (WST-1) assay, wound closure assay, Matrigel invasion assay and Annexin V assay were also performed, and we validated the functional effect of plumbagin for inhibition of cell proliferation, migration and invasion, and induction of apoptosis. Collectively, our findings suggest that plumbagin is a potential regulator of cellular growth, migration, invasion and apoptosis by inhibiting both constitutive and inducible STAT3 activity through induction of SHP1 in gastric cancer cells.

Prognostic and clinical significance of STAT3 and MMP9 in patients with gastric cancer: a meta-analysis of a Chinese cohort

As signal transducer and activator of transcription 3 (STAT3)-mediated signaling cascade directly contributes to tumor metastasis, numerous agents targeting STAT3 are in clinical development. However, reported data on the prognostic impact of STAT3 expression vary considerably. We aim to quantitatively summarize available evidences for evaluating the association between STAT3 and STAT3-regulated target gene, matrix metalloproteinase 9 (MMP9), and the prognosis of Chinese patients with gastric cancer. Searches were applied to PubMed and the Chinese National Knowledge Infrastructure database without any language restriction. A total of 5,757 patients were included in the final analyses. All results favored an association between high STAT3 expression and poor 5-year overall survival (risk ratio = 1.845, 95% confidence interval [CI] = 1.027-3.315). The reduced survival was heavily influenced by advanced tumor invasion (OR = 2.885, 95% CI = 2.034-4.094), lymph node metastasis (OR = 5.349, 95% CI = 3.807-7.516), distant metastasis (OR = 5.873, 95% CI = 2.641-13.062), dedifferentiation (OR = 2.516, 95% CI = 1.814-3.491), tumor size (OR = 1.918, 95% CI = 1.246-2.954), and higher TNM stage (OR = 4.171, 95% CI = 2.840-6.126). Similar results were observed in the meta-analyses of MMP9, with the magnitude of effect OR > 2. Our findings indicate that STAT3 and MMP9, as measured by IHC, are associated with worse survival and potentially mark invasion and metastasis in gastric cancer, especially in Chinese patients. More significantly, these two biomarkers may be converted from candidates to the routine clinical evaluation to help predict the outcome of gastric carcinoma patients.

Genetic Interactions of STAT3 and Anticancer Drug Development

Signal transducer and activator of transcription 3 (STAT3) plays critical roles in tumorigenesis and malignant evolution and has been intensively studied as a therapeutic target for cancer. A number of STAT3 inhibitors have been evaluated for their antitumor activity in vitro and in vivo in experimental tumor models and several approved therapeutic agents have been reported to function as STAT3 inhibitors. Nevertheless, most STAT3 inhibitors have yet to be translated to clinical evaluation for cancer treatment, presumably because of pharmacokinetic, efficacy, and safety issues. In fact, a major cause of failure of anticancer drug development is lack of efficacy. Genetic interactions among various cancer-related pathways often provide redundant input from parallel and/or cooperative pathways that drives and maintains survival environments for cancer cells, leading to low efficacy of single-target agents. Exploiting genetic interactions of STAT3 with other cancer-related pathways may provide molecular insight into mechanisms of cancer resistance to pathway-targeted therapies and strategies for development of more effective anticancer agents and treatment regimens. This review focuses on functional regulation of STAT3 activity; possible interactions of the STAT3, RAS, epidermal growth factor receptor, and reduction-oxidation pathways; and molecular mechanisms that modulate therapeutic efficacies of STAT3 inhibitors.