Suppression of IL-8-Src signalling axis by 17β-estradiol inhibits human mesenchymal stem cells-mediated gastric cancer invasion

Mesenchymal stem cells and their potential therapeutic benefits and challenges in the treatment and pathogenesis of gastric cancer

Mesenchymal stem/stromal cells (MSCs) are acknowledged for their remarkable ability to undergo differentiation into various cell types. In addition, they exhibit anti-tumor characteristics, prompting endeavors to modify MSCs for employment in cancer therapies. On the contrary, it is imperative to recognize that MSCs have been extensively linked to pathways that facilitate the advancement of tumors. Numerous research studies have sought to modify MSCs for clinical application; however, the outcomes have been ambiguous, potentially due to the heterogeneity of MSC populations. Furthermore, the conflicting roles of MSCs in suppressing and promoting tumor growth present a challenge to the appropriateness of their use in anti-cancer therapies. Currently, there exists a lack of comprehensive comprehension concerning the anti-tumor and pro-tumor characteristics of MSCs for gastric cancer (GC). This article discusses the influence of MSCs on GC, the underlying mechanisms, the origins of MSCs, and their effects. This review article also elucidates how MSCs exhibit dual characteristics of promoting and inhibiting tumor growth. Hence, it is of utmost importance that clinical inquiries aimed at utilizing MSCs as a therapeutic intervention for cancer consider the potentiality of MSCs to accelerate the progression of GC. It is crucial to exercise caution throughout the process of developing MSC-based cellular therapies to enhance their anti-cancer attributes while simultaneously eliminating their tumor-promoting impacts.

Characterization of gastric cancer-stimulated signaling pathways and function of CTGF in cancer-associated fibroblasts

BACKGROUND

Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME) that play an important role in cancer progression. Although the mechanism by which CAFs promote tumorigenesis has been well investigated, the underlying mechanism of CAFs activation by neighboring cancer cells remains elusive. In this study, we aim to investigate the signaling pathways involved in CAFs activation by gastric cancer cells (GC) and to provide insights into the therapeutic targeting of CAFs for overcoming GC.

METHODS

Alteration of receptor tyrosine kinase (RTK) activity in CAFs was analyzed using phospho-RTK array. The expression of CAFs effector genes was determined by RT-qPCR or ELISA. The migration and invasion of GC cells co-cultured with CAFs were examined by transwell migration/invasion assay.

RESULTS

We found that conditioned media (CM) from GC cells could activate multiple receptor tyrosine kinase signaling pathways, including ERK, AKT, and STAT3. Phospho-RTK array analysis showed that CM from GC cells activated PDGFR tyrosine phosphorylation, but only AKT activation was PDGFR-dependent. Furthermore, we found that connective tissue growth factor (CTGF), a member of the CCN family, was the most pronouncedly induced CAFs effector gene by GC cells. Knockdown of CTGF impaired the ability of CAFs to promote GC cell migration and invasion. Although the PDGFR-AKT pathway was pronouncedly activated in CAFs stimulated by GC cells, its pharmacological inhibition affected neither CTGF induction nor CAFs-induced GC cell migration. Unexpectedly, the knockdown of SRC and SRC-family kinase inhibitors, dasatinib and saracatinib, significantly impaired CTGF induction in activated CAFs and the migration of GC cells co-cultured with CAFs. SRC inhibitors restored the reduced expression of epithelial markers, E-cadherin and Zonula Occludens-1 (ZO-1), in GC cells co-cultured with CAFs, as well as CAFs-induced aggregate formation in a 3D tumor spheroid model.

CONCLUSIONS

This study provides a characterization of the signaling pathways and effector genes involved in CAFs activation, and strategies that could effectively inhibit it in the context of GC. Video Abstract.

Profiling and targeting cancer stem cell signaling pathways for cancer therapeutics

Tumorigenic cancer stem cells (CSCs) represent a subpopulation of cells within the tumor that express genetic and phenotypic profiles and signaling pathways distinct from the other tumor cells. CSCs have eluded many conventional anti-oncogenic treatments, resulting in metastases and relapses of cancers. Effectively targeting CSCs' unique self-renewal and differentiation properties would be a breakthrough in cancer therapy. A better characterization of the CSCs' unique signaling mechanisms will improve our understanding of the pathology and treatment of cancer. In this paper, we will discuss CSC origin, followed by an in-depth review of CSC-associated signaling pathways. Particular emphasis is given on CSC signaling pathways' ligand-receptor engagement, upstream and downstream mechanisms, and associated genes, and molecules. Signaling pathways associated with regulation of CSC development stand as potential targets of CSC therapy, which include Wnt, TGFβ (transforming growth factor-β)/SMAD, Notch, JAK-STAT (Janus kinase-signal transducers and activators of transcription), Hedgehog (Hh), and vascular endothelial growth factor (VEGF). Lastly, we will also discuss milestone discoveries in CSC-based therapies, including pre-clinical and clinical studies featuring novel CSC signaling pathway cancer therapeutics. This review aims at generating innovative views on CSCs toward a better understanding of cancer pathology and treatment.

Mesenchymal Stem Cells in Gastric Cancer: Vicious but Hopeful

Tumor progression depends on the collaborative interactions between tumor cells and the surrounding stroma. First-line therapies direct against cancer cells may not reach a satisfactory outcome, such as gastric cancer (GC), with high risk of recurrence and metastasis. Therefore, novel treatments and drugs target the effects of stroma components are to be promising alternatives. Mesenchymal stem cells (MSC) represent the decisive components of tumor stroma that are found to strongly affect GC development and progression. MSC from bone marrow or adjacent normal tissues express homing profiles in timely response to GC-related inflammation signals and anchor into tumor bulks. Then the newly recruited “naïve” MSC would achieve phenotype and functional alternations and adopt the greater tumor-supporting potential under the reprogramming of GC cells. Conversely, both new-comers and tumor-resident MSC are able to modulate the tumor biology via aberrant activation of oncogenic signals, metabolic reprogramming and epithelial-to-mesenchymal transition. And they also engage in remodeling the stroma better suited for tumor progression through immunosuppression, pro-angiogenesis, as well as extracellular matrix reshaping. On the account of tumor tropism, MSC could be engineered to assist earlier diagnosis of GC and deliver tumor-killing agents precisely to the tumor microenvironment. Meanwhile, intercepting and abrogating vicious signals derived from MSC are of certain significance for the combat of GC. In this review, we mainly summarize current advances concerning the reciprocal metabolic interactions between MSC and GC and their underlying therapeutic implications in the future.

Profiling of Steroid Metabolic Pathways in Human Plasma by GC-MS/MS Combined with Microwave-Assisted Derivatization for Diagnosis of Gastric Disorders

Steroid hormones are associated in depth to cellular signaling, inflammatory immune responses, and reproductive functions, and their metabolism alterations incur various diseases. In particular, quantitative profiling of steroids in plasma of patients with gastric cancer can provide a vast information to understand development of gastric cancer, since both sex hormones and glucocorticoids might be correlated with the pathological mechanisms of gastric cancer. Here, we developed a gas chromatography-tandem mass spectrometry-dynamic multiple reaction monitoring (GC-MS/MS-dMRM) method combined with solid-phase extraction (SPE) and microwave-assisted derivatization (MAD) to determine 20 endogenous steroids in human plasma. In this study, MAD conditions were optimized with respect to irradiation power and time. The SPE enabled effective cleanup and extraction for profiling of steroid hormones in human plasma samples. The MAD could improve laborious and time-consuming derivatization procedure, since dielectric heating using microwave directly increase molecular energy of reactants by penetrating through medium. Furthermore, dMRM method provided more sensitive determination of 20 steroids, compared to traditional MRM detection. The limits of quantification of steroids were below 1.125 ng/mL and determination coefficients of calibration curves were higher than 0.9925. Overall precision and accuracy results were below 19.93% and within ±17.04%, respectively. The developed method provided sufficient detection sensitivities and reliable quantification results. The established method was successfully applied to profile steroid metabolism pathways in plasma of patients with chronic superficial gastritis (CSG), intestinal metaplasia (IM), and gastric cancer. Statistical significances of steroid plasma levels between gastric disorder groups were investigated. In conclusion, this method provided comprehensive profiling of 20 steroids in human plasma samples and will be helpful to discover potential biomarkers for the development of gastric cancer and to further understand metabolic syndrome.

Conjugated linoleic acid improves endothelial Ca2+ signaling by blocking growth factor and cytokine-mediated Cx43 phosphorylation

Sustained Ca²⁺ burst signaling is crucial for endothelial vasodilator production and is disrupted by growth factors and cytokines. Conjugated linoleic acid (CLA), a Src inhibitor in certain preparations, is generally regarded as safe during pregnancy by the FDA. Multiple CLA preparations; t10, c12 or c9, t11 CLA, or a 1:1 mixture of the two were administered before growth factor or cytokine treatment. Growth factors and cytokines caused a significant decrease in Ca²⁺ burst numbers in response to ATP stimulation. Both t10, c12 CLA and the 1:1 mixture rescued VEGF₁₆₅ or TNFα inhibited Ca²⁺ bursts and correlated with Src-specific phosphorylation of connexin 43. VEGF₁₆₅, TNFα, and IL-6 in combination at physiologic concentrations revealed IL-6 amplified the inhibitory effects of lower dose of VEGF₁₆₅ and TNFα. Again, the 1:1 CLA mixture was most effective at rescue of function. Therefore, CLA formulations may be a promising treatment for endothelial dysfunction in diseases such as preeclampsia.

IL-8 and MCP-1/CCL2 regulate proteolytic activity in triple negative inflammatory breast cancer a mechanism that might be modulated by Src and Erk1/2

Inflammatory breast cancer (IBC) is a highly metastatic and lethal breast cancer. As many as 25-30% of IBCs are triple negative (TN) and associated with low survival rates and poor prognosis. We found that the microenvironment of IBC is characterized by high infiltration of tumor associated macrophages (TAMs) and by over-expression of the cysteine protease cathepsin B (CTSB). TAMs in IBC secrete high levels of the cytokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1/CCL2) compared to non-IBC patients. Herein, we tested the roles of IL-8 and MCP-1/CCL2 in modulating proteolytic activity and invasiveness of TN-non-IBC as compared to TN-IBC and addressed the underlying molecular mechanism(s) for both cytokines. Quantitative real time PCR results showed that IL-8 and MCP-1/CCL2 were significantly overexpressed in tissues of TN-IBCs. IL-8 and MCP-1/CCL2 induced CTSB expression and activity of the p-Src and p-Erk1/2 signaling pathways relevant for invasion and metastasis in TN-non-IBC, HCC70 cells and TN-IBC, SUM149 cells. Dasatinib, an inhibitor of p-Src, and U0126, an inhibitor of p-Erk1/2, down-regulated invasion and expression of CTSB by HCC70 and SUM149 cells, a mechanism that is reversed by IL-8 and MCP-1/CCL2. Our study shows that targeting the cytokines IL-8 and MCP-1/CCL2 and associated signaling molecules may represent a promising therapeutic strategy in TN-IBC patients.

The Crosstalk between Src and Hippo/YAP Signaling Pathways in Non-Small Cell Lung Cancer (NSCLC)

The advancement of new therapies, including targeted therapies and immunotherapies, has improved the survival of non-small-cell lung cancer (NSCLC) patients in the last decade. Some NSCLC patients still do not benefit from therapies or encounter progressive disease during the course of treatment because they have intrinsic resistance, acquired resistance, or lack a targetable driver mutation. More investigations on the molecular biology of NSCLC are needed to find useful biomarkers for current therapies and to develop novel therapeutic strategies. Src is a non-receptor tyrosine kinase protein that interacts with cell surface growth factor receptors and the intracellular signaling pathway to maintain cell survival tumorigenesis in NSCLC. The Yes-associated protein (YAP) is one of the main effectors of the Hippo pathway and has been identified as a promoter of drug resistance, cancer progression, and metastasis in NSCLC. Here, we review studies that have investigated the activation of YAP as mediated by Src kinases and demonstrate that Src regulates YAP through three main mechanisms: (1) direct phosphorylation; (2) the activation of pathways repressing Hippo kinases; and (3) Hippo-independent mechanisms. Further work should focus on the efficacy of Src inhibitors in inhibiting YAP activity in NSCLC. In addition, future efforts toward developing potentially reasonable combinations of therapy targeting the Src–YAP axis using other therapies, including targeted therapies and/or immunotherapies, are warranted.

Helicobacter pylori Infection-Induced Hepatoma-Derived Growth Factor Regulates the Differentiation of Human Mesenchymal Stem Cells to Myofibroblast-Like Cells

Hepatoma-derived growth factor (HDGF) plays a critical role in tumor cell proliferation, anti-apoptosis, VEGF expression, lymph node metastasis and poor prognosis in human gastric cancer. Gastric cancer, as one of the most prevalent cancers worldwide, is the second leading cause of cancer-related mortality in the world for the prognosis of gastric cancer is generally poor, especially in patients with advanced stage. Helicobacter pylori (H. pylori) infection causes the chronic inflammation of stomach as well as the development of gastric cancer, with a three to six-fold increased risk of gastric cancer. Carcinoma-associated fibroblasts (CAFs) are myofibroblasts in tumor microenvironment, which possess various abilities to promote the progression of cancer by stimulating neoangiogenesis, proliferation, migration, invasion and therapy resistance of tumor cell. Mesenchymal stem cells (MSCs) are reported to promote tumor malignance through differentiation of MSCs toward CAFs. In the present study, we demonstrated that H. pylori infection promotes HDGF expression in human gastric cancer cells. HBMMSCs treated with HDGF assume properties of CAF-like myofibroblastic phenotypes, including expression of myofibroblast markers (α-smooth muscle actin (α-SMA), procollagen α1, tropomyoson I, desmin, fibroblast activation protein (FAP)), and fibroblast markers (prolyl-4-hydroxylase A1 (PHA1) and fibroblast specific protein-1 (FSP-1)/S100A4). HDGF recruits HBMMSCs, and then HBMMSCs further contributes to cell survival and invasive motility in human gastric cancer cells. Treatment of HDGF neutralizing antibody (HDGF-NAb) and serum significantly inhibit HDGF-regulated differentiation and recruitment of HBMMSCs. These findings suggest that HDGF might play a critical role in gastric cancer progress through stimulation of HBMMSCs differentiation to myofibroblast-like cells.

CXCL8 derived from tumor-associated macrophages and esophageal squamous cell carcinomas contributes to tumor progression by promoting migration and invasion of cancer cells

Tumor-associated macrophages (TAMs) are involved in tumor progression and poor prognosis in several malignancies. We previously demonstrated the interaction between high numbers of infiltrating TAMs and poor prognosis in esophageal squamous cell carcinomas (ESCCs). To investigate the significance of TAMs in ESCC, we conducted a cDNA microarray analysis of peripheral blood monocytes (PBMo)-derived macrophages and PBMo-derived macrophages stimulated with conditioned media of TE-series ESCC cell lines (TAM-like PBMo-derived macrophages). C-X-C motif chemokine ligand 8 (CXCL8) was up-regulated in the TAM-like PBMo-derived macrophages. Here we confirmed a high expression level of CXCL8 in TAM-like PBMo-derived macrophages and the expression of CXCR1/2, known as CXCL8 receptors, in TE-series ESCC cell lines. Recombinant human CXCL8 induced the ESCC cell lines’ migration and invasion by the phosphorylation of Akt and Erk1/2. In indirect co-cultures, not only signal pathway inhibitors but also neutralizing antibodies against CXCL8, CXCR1 and CXCR2 suppressed these phenotypes induced by TAM-like PBMo-derived macrophages. Immunohistochemical analysis of 70 resected ESCC samples showed that high expression levels of CXCL8 in ESCC tissues were significantly associated with lymph node metastasis and poor prognosis. These results suggest that CXCL8 up-regulated in the microenvironment may contribute to ESCC progression by promoting cancer cells’ migration and invasion.

Cell cycle-dependent translocation and regulatory mechanism of CacyBP/SIP in gastric cancer cells

Our previous results showed that calcyclin-binding protein/Siah-1-interacting protein (CacyBP/SIP) inhibits the proliferation and tumorigenicity of gastric cancer; however, the exact mechanism remains unclear, especially from the aspect of cell cycle. The subcellular localization of CacyBP/SIP, Siah-1, and Skp1 in SGC7901 gastric cancer cells was assessed by immunofluorescence after cell cycle synchronization. Levels of CacyBP/SIP, Siah-1, Skp1, β-catenin, and p-ERK1/2 were analyzed by western blotting. CacyBP/SIP phosphorylation (p-CacyBP/SIP) and the combining capacity of Siah-1 and Skp1 with CacyBP/SIP in nucleoprotein were determined by immunoprecipitation. CacyBP/SIP, Siah-1, and Skp1 were mainly in the cytoplasm in the G1 phase, but translocated to the nucleus during G2. Their expression in total protein was not altered, but elevated in the G2 phase in nucleoprotein. The CacyBP/SIP nucleus translocation of cells transfected with mutant CacyBP/SIP that does not bind S100 (CacyBP-ΔS100) was significantly increased compared with wild-type CacyBP/SIP. In the G2 phase, p-CacyBP/SIP expression and the combining capacity of Siah-1 and Skp1 with CacyBP/SIP were all increased, whereas levels of β-catenin and p-ERK1/2 reduced, compared with the G1 phase. CacyBP/SIP or CacyBP-ΔS100 overexpression was correlated with constitutively low β-catenin expression and affected its level through cell cycle. CacyBP/SIP overexpression led to retarded proliferation, G1 arrest, and β-catenin reduction, which could be abolished by lithium chloride, β-catenin activator, and further enhanced by the Wnt inhibitor XAV-939. In addition, CacyBP-ΔS100 further suppressed cell proliferation and induced G1 arrest compared with CacyBP/SIP. In conclusion, CacyBP/SIP nuclear localization, dependent on S100 protein, suppresses gastric cancer tumorigenesis through β-catenin degradation and the dephosphorylation of ERK1/2 during the G2 phase.

Impact of inducible nitric oxide synthase (iNOS) expression on triple negative breast cancer outcome and activation of EGFR and ERK signaling pathways

Inflammation is implicated in triple negative breast cancer (TNBC) progression. TNBC carries a worse prognosis than other breast cancer subtypes, and with the clinical and molecular heterogeneity of TNBC, there is a lack of effective therapeutic targets available. Identification of molecular targets for TNBC subtypes is crucial towards personalized patient stratification. Inducible nitric oxide synthase (iNOS) has been shown to induce p53 mutation accumulation, basal-like gene signature enrichment and transactivation of the epidermal growth factor receptor (EGFR) via s-nitrosylation. Herein we report that iNOS is associated with disease recurrence, distant metastasis and decreased breast cancer specific survival in 209 cases of TNBC. Employing TNBC cell lines representing normal basal breast, and basal-like 1 and basal-like 2 tumors, we demonstrate that nitric oxide (NO) induces EGFR-dependent ERK phosphorylation in basal-like TNBC cell lines. Moreover NO mediated cell migration and cell invasion was found to be dependent on EGFR and ERK activation particularly in basal-like 2 TBNC cells. This occurred in conjunction with NF-κB activation and increased secretion of pro-inflammatory cytokines IL-8, IL-1β and TNF-α. This provides substantial evidence for EGFR as a therapeutic target to be taken into consideration in the treatment of a specific subset of basal-like TNBC overexpressing iNOS.

d,l-Sulforaphane Induces ROS-Dependent Apoptosis in Human Gliomablastoma Cells by Inactivating STAT3 Signaling Pathway

d,l-Sulforaphane (SFN), a synthetic analogue of broccoli-derived isomer l-SFN, exerts cytotoxic effects on multiple tumor cell types through different mechanisms and is more potent than the l-isomer at inhibiting cancer growth. However, the means by which SFN impairs glioblastoma (GBM) cells remains poorly understood. In this study, we investigated the anti-cancer effect of SFN in GBM cells and determined the underlying molecular mechanisms. Cell viability assays, flow cytometry, immunofluorescence, and Western blot results revealed that SFN could induced apoptosis of GBM cells in a dose- and time-dependent manner, via up-regulation of caspase-3 and Bax, and down-regulation of Bcl-2. Mechanistically, SFN treatment led to increase the intracellular reactive oxygen species (ROS) level in GBM cells. Meanwhile, SFN also suppressed both constitutive and IL-6-induced phosphorylation of STAT3, and the activation of upstream JAK2 and Src tyrosine kinases, dose- and time-dependently. Moreover, blockage of ROS production by using the ROS inhibitor N-acetyl-l-cysteine totally reversed SFN-mediated down-regulation of JAK2/Src-STAT3 signaling activation and the subsequent effects on apoptosis by blocking the induction of apoptosis-related genes in GBM cells. Taken together, our data suggests that SFN induces apoptosis in GBM cells via ROS-dependent inactivation of STAT3 phosphorylation. These findings motivate further evaluation of SFN as a cancer chemopreventive agent in GBM treatment.

IL-13 receptor α2 stimulates human glioma cell growth and metastasis through the Src/PI3K/Akt/mTOR signaling pathway

Glioma is a malignant tumor that affects all kinds of people all over the world. It demonstrates remarkable infiltrative and invasive features. The high expression of interleukin-13 receptor subunit alpha-2 (IL-13Rα2) reportedly plays a pivotal role in some cancers. However, whether IL-13Rα2 contributes to glioma remains unknown. This study demonstrates that IL-13Rα2 is significantly up-regulated in human glioma tissue samples. It is also associated with late stages of disease progression and diminished survival in glioma patients. Gain- and loss-of-function studies demonstrate that IL-13Rα2 promotes the growth, migration, and invasion of glioma cells. In addition, mechanistic investigations show that IL-13Rα2 activates Scr, phosphatidylinositol 3 kinase (PI3K), Akt, and mTOR. Also, restraining Scr in glioma cells attenuates the activation of Scr/PI3K/Akt/mTOR pathway by IL-13Rα2, whereas the silencing of Scr markedly rescues the pro-invasive effect of IL-13Rα2. In conclusion, our results suggest that the high expression of IL-13Rα2 is significantly associated with the growth and metastasis of human glioma cells via the Scr/PI3K/Akt/mTOR pathway, while IL-13Rα2 may be a potential therapeutic target for glioma treatment.

IL-8 interacts with metadherin promoting proliferation and migration in gastric cancer

It has been reported that IL-8 was involved in the promotion of invasion of Gastric Cancer (GC), however the underlying mechanism by which IL-8 was observed to be able to promote invasion remains unknown. Here, in our study, IL-8 was shown to be significantly up-regulated in GC compared with paired normal control tissues whose expression was markedly associated with inferior overall prognosis; and IL-8 was displayed to be capable of directly interacting with metadherin (MTDH), which in turn can up-regulate IL-8 expression. Blockage of IL-8/MTDH using specific mono-antibody can abolish the invasion IL-8 mediated. Taken together, our results may provide a novel explanation of working mechanism of IL-8 in the invasion of GC.