The nanobody targeting PD-L1 and CXCR4 counteracts pancreatic stellate cell-mediated tumour progression by disrupting tumour microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal malignancy worldwide owing to its complex tumour microenvironment and dense physical barriers. Stromal-derived factor-1 (SDF-1), which is abundantly secreted by tumour stromal cells, plays a pivotal role in promoting PDAC growth and metastasis. In this study, we investigated the impact and molecular mechanisms of the anti-PD-L1&CXCR4 bispecific nanobody on the TME and their consequent interference with PDAC progression. We found that blocking the SDF-1/CXCR4 signalling pathway delayed the epithelial-mesenchymal transition in pancreatic cancer cells. Anti-PD-L1&CXCR4 bispecific nanobody effectively suppress the secretion of SDF-1 by pancreatic stellate cells and downregulate the expression of smooth muscle actin alpha(α-SMA), thereby preventing the activation of cancer-associated fibroblasts by downregulating the PI3K/AKT signaling pathway. This improves the pancreatic tumour microenvironment, favouring the infiltration of T cells into the tumour tissue. In conclusion, our results suggest that the anti-PD-L1&CXCR4 bispecific nanobody exerts an antitumor immune response by changing the pancreatic tumour microenvironment. Hence, the anti-PD-L1&CXCR4 bispecific nanobody is a potential candidate for pancreatic cancer treatment.

Bushen Huoxue recipe ameliorates ovarian function via promoting BMSCs proliferation and homing to ovaries in POI mice

BACKGROUND

Premature ovarian insufficiency (POI) is a tricky puzzle in the field of female reproductive medicine. Bushen Huoxue recipe (BHR), a traditional Chinese medicine compound based on the combination of kidney-tonifying and blood-activating functions, has shown excellent efficacy in improving female irregular menstruation, POI, and infertility. However, the potential mechanism of BHR in POI treatment has not yet been elucidated. Bone marrow mesenchymal stem cells (BMSCs), a type of pluripotent stem cells, have received increasing attention for their significant role in improving ovarian function and restoring fertility in women with POI.

PURPOSE

This study aimed to evaluate the therapeutic effect of BHR in POI mice and explore its potential mechanism.

METHODS

A POI mouse model was established with a single intraperitoneal injection of 120 mg/kg cyclophosphamide (CTX). Distilled water, BHR, or dehydroepiandrosterone was administered via gavage for 28 consecutive days. The effect of BHR on ovarian function in POI mice was evaluated by assessing the estrous cycle, ovarian morphology, follicular development, hormone levels, and angiogenesis. The proportion of BMSCs in bone marrow, peripheral blood, and ovary was analyzed via flow cytometry, and the level of molecules mediating migration and homing in ovary was measured. Cell viability assays, scratch healing assays and transwell migration assays were performed to explore the effect of BHR on BMSCs proliferation and migration in vitro, and its potential mechanism was explored.

RESULTS

BHR significantly ameliorated estrous cycle disorders, hormone disorders, ovarian morphology, ovarian microvascular formation, and ovarian reserve in POI mice. Meanwhile, the number of BMSCs number in the bone marrow, peripheral blood, and ovary was apparently increased. Of note, BHR increased the level of hepatocyte growth factor (HGF)/cellular mesenchymal epithelial transition factor (cMET) and stromal cell-derived factor-1(SDF-1)/CXC chemokine receptor 4 (CXCR4) in the ovaries of POI mice. Moreover, BHR treatment promoted BMSCs proliferation and migration in vitro, with a significant increase in the level of proliferating cell nuclear antigen, cMET, and CXCR4.

CONCLUSIONS

BHR effectively restored ovarian reserve, ovarian function, and ovarian angiogenesis in CTX-induced POI mice. In addition, BHR promoted BMSCs proliferation, migration, and homing to the ovary, which was mediated by the SDF-1/CXCR4 and HGF/cMET signaling axis. Finally, the amelioration of ovarian reserve and ovarian function in CTX-induced POI mice by BHR may be related to its promotion of endogenous BMSCs proliferation and homing.

Modeling the SDF-1/CXCR4 protein using advanced artificial intelligence and antagonist screening for Japanese anchovy

SDF-1/CXCR4 chemokine signaling are indispensable for cell migration, especially the Primordial Germ Cell (PGC) migration towards the gonadal ridge during early development. We earlier found that this signaling is largely conserved in the Japanese anchovy (Engraulis japonicus, EJ), and a mere treatment of CXCR4 antagonist, AMD3100, leads to germ cell depletion and thereafter gonad sterilization. However, the effect of AMD3100 was limited. So, in this research, we scouted for CXCR4 antagonist with higher potency by employing advanced artificial intelligence deep learning-based computer simulations. Three potential candidates, AMD3465, WZ811, and LY2510924, were selected and in vivo validation was conducted using Japanese anchovy embryos. We found that seven transmembrane motif of EJ CXCR4a and EJ CXCR4b were extremely similar with human homolog while the CXCR4 chemokine receptor N terminal (PF12109, essential for SDF-1 binding) was missing in EJ CXCR4b. 3D protein analysis and cavity search predicted the cavity in EJ CXCR4a to be five times larger (6,307 Å³) than that in EJ CXCR4b (1,241 Å³). Docking analysis demonstrated lower binding energy of AMD3100 and AMD3465 to EJ CXCR4a (Vina score -9.6) and EJ CXCR4b (Vina score -8.8), respectively. Furthermore, we observed significant PGC mismigration in microinjected AMD3465 treated groups at 10, 100 and 1 × 105 nM concentration in 48 h post fertilized embryos. The other three antagonists showed various degrees of PGC dispersion, but no significant effect compared to their solvent control at tested concentrations was observed. Cumulatively, our results suggests that AMD3645 might be a better candidate for abnormal PGC migration in Japanese anchovy and warrants further investigation.

The dynamic changes of monocytes and cytokines during wound healing post-burn injury

BACKGROUND

Burn injury is a sudden and traumatic injury that affects a large part of the population worldwide, who are placed at high risk of developing hypertrophic scars (HTS). HTS are a fibrotic scar resulting in painful contracted and raised scarring, affecting mobility in joints and work life, as well as cosmetically. The aim of this research was to enhance our understanding of the systematic response of monocytes and cytokines in wound healing after burn injury, in order to develop novel approaches to prevention and treatment of HTS.

METHODS

Twenty-seven burn patients and thirteen healthy individuals were recruited in this study. Burn patients were stratified by burn total body surface area (TBSA). Peripheral blood samples were taken post-burn injury. Serum and peripheral blood mononuclear cells (PBMCs) were separated from the blood samples. This research investigated cytokines IL-6, IL-8, IL1RA, IL-10, and chemokine pathways SDF-1/CXCR4, MCP-1/CCR2, RANTES/CCR5 during the wound healing process in burn patients with varying severity of injuries by using enzyme-linked immunosorbent assays. PBMCs were stained for monocytes and the chemokine receptors by flow cytometry. Statistical analysis was done by one-way ANOVA with a Tukey correction, and regression analysis was performed using Pearson's Correlation analysis.

RESULTS

The CD14⁺CD16^- monocyte subpopulation is larger in patients who developed HTS at 4-7 days. The CD14⁺CD16⁺ monocyte subpopulation is smaller in the first week of injury, where it is similar after 8 days. Burn injury increased CXCR4, CCR2, and CCR5 expressions in CD14⁺ CD16⁺ monocytes. Increases in MCP-1 at 0-3 days after burn injury was positively correlated with burn severity. IL-6, IL-8, RANTES, and MCP-1 significantly increased with increasing burn severity.

CONCLUSIONS

Monocytes and their chemokine receptors, as well as systemic levels of cytokines in wound healing of burn patients and scar development will require ongoing assessment to enhance our understanding of the abnormal wound healing after burn injury.

A static magnetic field enhances the repair of osteoarthritic cartilage by promoting the migration of stem cells and chondrogenesis

Objective

To investigate the therapeutic effects of static magnetic field (SMF) and its regulatory mechanism in the repair of osteoarthritic cartilage.

Methods

Fourteen-week-old female C57BL/6 mice were randomly divided into the sham operation group and the osteoarthritis (OA) groups with and without SMF application. SMF was applied at 200 ​mT for two consecutive weeks. Changes in knee cartilage were examined by histomorphometry, and the chondrogenesis and migration of endogenous stem cells were assessed. The expression of SRY-related protein 9 (SOX9), Collagen type II (COL2), matrix metallopeptidase 13 (MMP13), stromal cell-derived factor 1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4), Piezo1 and other genes was evaluated, and the mechanism of SMF's action was tested using the CXCR4 inhibitor, AMD3100, and Piezo1 siRNA.

Results

SMF significantly decreased the OARSI scores after induction of OA. SMF was beneficial to chondrogenesis by elevating SOX9. In the OA mouse model, an increase in MMP13 with a decrease in COL2 led to the destruction of the cartilage extracellular matrix, which was suppressed by SMF. SMF promoted the migration of cartilage-derived stem/progenitor cells and bone marrow-derived mesenchymal stem cells (MSCs). It increased SDF-1 and CXCR4, while the CXCR4 inhibitor significantly suppressed the beneficial effects of SMF. The application of Piezo1 siRNA inhibited the SMF-induced increase of CXCR4.

Conclusion

SMF enhanced chondrogenesis and improved cartilage extracellular matrices. It activated the Piezo1-mediated SDF-1/CXCR4 regulatory axis and promoted the migration of endogenous stem cells. Collectively, it attenuated the pathological progression of cartilage destruction in OA mice.

The Translational potential of this article

The findings in this study provided convincing evidence that SMF could enhance cartilage repair and improve OA symptoms, suggesting that SMF could have clinical value in the treatment of OA.

Knee Loading Enhances the Migration of Adipose-Derived Stem Cells to the Osteoarthritic Sites Through the SDF-1/CXCR4 Regulatory Axis

Osteoarthritis (OA) is a whole joint disorder that is characterized by cartilage damage and abnormal remodeling of subchondral bone. Injecting adipose-derived stem cells (ASCs) into the knee joint cavity can assist in repairing osteoarthritic joints, but their ability to migrate to the damaged site is limited. Our previous studies have shown that knee loading can improve the symptoms of OA, but the effect and mechanism of knee loading on the migration of ASCs in OA remain unclear. We employed a mouse model of OA in the knee and applied knee loading (1 N at 5 Hz for 6 min/day for 2 weeks) after the intra-articular injection of ASCs. The cartilage and subchondral bone repair were assessed by histopathological analysis. Immunofluorescence assays were also used to analyze the migration of ASCs. Using cell cultures, we evaluated the migration of ASCs using the transwell migration and wound healing assays. In vivo experiments showed that knee loading promoted the migration of ASCs, increased the local SDF-1 level, and accelerated the repair of the OA-damaged sites. Mechanistically, the observed effects were blocked by the SDF-1/CXCR4 inhibitor. The in vitro results further revealed that knee loading promoted the migration of ASCs and the inhibition of SDF-1/CXCR4 significantly suppressed the beneficial loading effect. The results herein suggested that the migration of ASCs was enhanced by knee loading through the SDF-1/CXCR4 regulatory axis, and mechanical loading promoted the joint-protective effect of ASCs.

Standardized Astragalus Mongholicus Bunge-Curcuma Aromatica Salisb. Extract Efficiently Suppresses Colon Cancer Progression Through Gut Microbiota Modification in CT26-Bearing Mice

Altered gut microbiota and a damaged colon mucosal barrier have been implicated in the development of colon cancer. Astragalus mongholicus Bunge-Curcuma aromatica Salisb. (ACE) is a common herbal drug pair that widely used clinically to treat cancer. However, whether the anti-cancer effect of ACE is related to gut microbiota remains unclear yet. We standardized ACE and investigated the effects of ACE on tumour suppression and analyze the related mechanisms on gut microbiota in CT26 colon cancer-bearing mice in the present study. Firstly, four flavonoids (calycosin-7-glucoside, ononin, calycosin, formononetin) and three astragalosides (astragaloside A, astragaloside II, astragaloside I) riched in Astragalus mongholicus Bunge, three curcumins (bisdemethoxycurcumin, demethoxycurcumin, curcumin) and four essential oils (curdione, curzerene, germacrone and β-elemene) from Curcuma aromatica Salisb., in concentrations from 0.08 to 2.07 mg/g, were examined in ACE. Then the results in vivo studies indicated that ACE inhibited solid tumours, liver and spleen metastases of colon cancer while simultaneously reducing pathological tissue damage. Additionally, ACE regulated gut microbiota dysbiosis and the short chain fatty acid content in the gut, repaired intestinal barrier damage. ACE treatment suppressed the overgrowth of conditional pathogenic gut bacteria, including Escherichia-Shigella, Streptococcus and Enterococcus, while the probiotic gut microbiota like Lactobacillus, Roseburia, Prevotellaceae_UCG-001 and Mucispirillum were increased. More interestingly, the content level of SCFAs such as propionic acid and butyric acid was increased after ACE administration, which further mediates intestinal SDF-1/CXCR4 signalling pathway to repair the integrity of the intestinal barrier, decrease Cyclin D1 and C-myc expressions, eventually suppress the tumor the growth and metastasis of colon cancer. To sum up, the present study demonstrated that ACE could efficiently suppress colon cancer progression through gut microbiota modification, which may provide a new explanation of the mechanism of ACE against colon cancer.

Retinoblastoma tumor suppressor gene 1 enhances 5-Fluorouracil chemosensitivity through SDF-1/CXCR4 axis by regulating autophagy in gastric cancer

Due to lack of effective biomarkers for early diagnosis, most patients are diagnosed with advanced gastric cancer and have lower survival rates. 5-Fluorouracil (5-FU) is one of commonly used drugs for chemotherapy of gastric cancer, but drug resistance limits the wide application of agents. Retinoblastoma tumor suppressor gene 1 (RB1) is a key regulator in the progression of various human cancers, including gastric cancer. However, the effects of RB1 on chemosensitivity and the underlying mechanisms in gastric cancer (GC) are not clear. In this study, expressions of RB1 in GC cell lines were evaluated by RT-qPCR and western blot assay. CCK-8 was applied to examine the effect of 5-FU on cell viability. Meanwhile, IC50 values were calculated. The drug-resistance protein MDR1 and autophagy-related proteins were detected by western blot assay. Flow cytometry was used to detect cell cycle. The results showed that RB1 expressions were downregulated in GC cell lines and had significant differences between 5-FU resistance cell lines (SNU-620/5-FU and NUGC-3/5-FU) and non-resistance cell lines (SNU-620 and NUGC-3). Overexpression of RB1 enhanced 5-FU sensitivity of GC cells and caused cell cycle arrest in the S phase. Meanwhile, autophagy-related proteins were downregulated. Mechanistically, SDF-1/CXCR4 participated in the regulation of RB1 on cell autophagy. Autophagy activator, SDF-1 treatment and CXCR4 activation reversed the promoted effects of RB1 on 5-FU sensitivity in GC cells. In conclusion, our data revealed that RB1 was downregulated in GC cell lines. RB1 overexpression enhanced 5-FU chemosensitivity in GC cells by regulating cell autophagy via SDF-1/CXCR4 pathway. RB1 might serve as a promising therapeutic target of GC.

Sulfatase 2-Induced Cancer-Associated Fibroblasts Promote Hepatocellular Carcinoma Progression via Inhibition of Apoptosis and Induction of Epithelial-to-Mesenchymal Transition

Background

Sulfatase 2 (SULF2) removes the 6-O-sulfate groups from heparan sulfate proteoglycans (HSPG) and consequently alters the binding sites for various signaling molecules. Here, we elucidated the role of SULF2 in the differentiation of hepatic stellate cells (HSCs) into carcinoma-associated fibroblasts (CAFs) in the hepatocellular carcinoma (HCC) microenvironment and the mechanism underlying CAF-mediated HCC growth.

Methods

The clinical relevance of SULF2 and CAFs was examined using in silico and immunohistochemical (IHC) analyses. Functional studies were performed to evaluate the role of SULF2 in the differentiation of HSCs into CAFs and elucidate the mechanism underlying CAF-mediated HCC growth. Mechanistic studies were performed using the chromatin immunoprecipitation, luciferase reporter, and RNA immunoprecipitation assays. The in vitro findings were verified using the nude HCC xenograft mouse model.

Results

The Cancer Genome Atlas (TCGA) database and IHC analyses revealed that the expression of CAF markers, which was positively correlated with that of SULF2 in the HCC tissues, predicted unfavorable postsurgical outcomes. Co-culturing HSCs with HCC cells expressing SULF2 promoted CAF differentiation. Additionally, CAFs repressed HCC cell apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway. Meanwhile, SULF2-induced CAFs promoted epithelial-to-mesenchymal transition (EMT) of HCC cells by modulating the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. Studies using HCC xenograft mouse models demonstrated that OIP5-AS1 induced EMT by upregulating SNAI1 and promoted HCC growth in vivo.

Conclusion

These data indicated that SULF2 secreted by the HCC cells induced the differentiation of HSCs into CAFs through the TGFβ1/SMAD3 signaling pathway. SULF2-induced CAFs attenuated HCC apoptosis by activating the SDF-1/CXCR4/PI3K/AKT signaling pathway and induced EMT through the SDF-1/CXCR4/OIP5-AS1/miR-153-3p/SNAI1 axis. This study revealed a novel mechanism involved in the crosstalk between HCC cells and CAFs in the tumor microenvironment, which can aid in the development of novel and efficient therapeutic strategies for primary liver cancer.

Assessing the effect and related mechanism of naringenin on the proliferation, osteogenic differentiation and endothelial differentiation of human periodontal ligament stem cells

Naringenin (NAR) is a natural flavonoid which exerts extensive biological activity, including anti-oxidation, anti-inflammation, anti-cancer, immune regulation and so on. However, the effect and mechanism of NAR in the alveolar bone regeneration are still unclear, which limits its clinical use. Hence, we investigated the effects of NAR in the proliferation, osteogenic and endothelial differentiation of human periodontal ligament stem cells (hPDLSCs) and explore the possible mechanism. The results showed that the proper concentrations (100 nM-10 μM) of NAR can promote the proliferation rate, osteogenic and endothelial differentiation of hPDLSCs. And the 1 μM NAR had the best proliferation promoting effect, while the 10 μM NAR had the best ability of promoting osteogenic and endothelial differentiation. NAR also promoted the mRNA expression of SDF-1 in a concentration dependent manner in PDLSCs. After adding the selective CXCR4 antagonist AMD3100, the osteogenic effect of NAR on PDLSCs is slightly enhanced, while the endothelial differentiation effect of NAR on hPDLSCs is attenuated. In summary, these results indicated that NAR promoted the proliferation of hPDLSCs, and promoted endothelial differentiation of hPDLSCs via SDF-1 to activate SDF-1/CXCR4 signaling pathway. However, the mechanism of which SDF-1 related signaling pathway is activated by NAR to enhance the osteogenic differentiation of hPDLSCs still needs to be investigated.

EPO enhances the protective effects of MSCs in experimental hyperoxia-induced neonatal mice by promoting angiogenesis

Bronchopulmonary dysplasia (BPD) is the most common type of chronic lung disease in infancy; however, there is no effective treatment for it. In the present study, a neonatal mouse BPD model was established by continuous exposure to high oxygen (HO) levels. Mice were divided randomly into 5 groups: control, BPD, EPO, MSCs, and MSCs+EPO. At 2 weeks post-treatment, vessel density and the expression levels of endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), and its receptor C-X-C chemokine receptor type 4 (CXCR4) were significantly increased in the MSC+EPO group compared with the EPO or MSCs group alone; moreover, EPO significantly enhanced MSCs proliferation, migration, and anti-apoptosis ability in vitro. Furthermore, the MSCs could differentiate into cells that were positive for the type II alveolar epithelial cell (AECII)-specific marker surfactant protein-C, but not positive for the AECI-specific marker aquaporin 5. Our present results suggested that MSCs in combination with EPO could significantly attenuate lung injury in a neonatal mouse model of BPD. The mechanism may be by the indirect promotion of angiogenesis, which may involve the SDF-1/CXCR4 axis.

Bone marrow-derived interstitial cells of cajal are increased by electroacupuncture in the colon of diabetic mice

BACKGROUND AND AIM

Insufficiency of interstitial cells of cajal (ICC) in the muscular plexus of colon has been proved in diabetic mice. Electroacupuncture (EA) at ST36 can accelerate ICC supplement in the colon of diabetic mice, but the source of increased ICC has not been clearly explored. Bone marrow cells possess the potential of migration and differentiation into ICC of the intestine. Our aim is to explore the effects of EA on variations of bone marrow-derived ICC in the colon of diabetic mice as well as its mechanism.

METHODS

Wild C57BL/6 mice were divided into six groups with random assignment method: control group, diabetic mellitus (DM) group, bone marrow transplantation (BMT) + DM group, BMT + DM + sham EA group, BMT + DM + low-frequency EA group, and BMT + DM + high-frequency EA group. Flow cytometric method was adopted to identify the chimera model. The specific location and expression levels of c-Kit+ green fluorescent protein (GFP+) cells in colon were detected by immunofluorescence. Western blot and quantitative polymerase chain reaction were used to assess the expression level of c-Kit, GFP, membrane-band stem cell factor (mSCF), p-ERK, p-c-Jun, ETV1, stromal cell-derived factor 1 (SDF-1), CXCR4, transforming growth factor β1 (TGF-β1), and smad3.

RESULTS

c-Kit+ GFP+ cells in the muscular plexus of colon were apparently increased in the EA groups; the protein and mRNA expression level of CXCR4, SDF-1, TGF-β1, smad3, c-kit, mSCF, p-ERK, p-c-Jun, and ETV1 were elevated in the EA groups.

CONCLUSIONS

Electroacupuncture can effectively increase bone marrow-derived ICC in the colon by SDF-1/CXCR4, TGF-β1/Smad3, and mSCF/Kit-p-ERK/p-c-Jun-ETV1 signal pathway.

Combined therapy with atorvastatin and atorvastatin-pretreated mesenchymal stem cells enhances cardiac performance after acute myocardial infarction by activating SDF-1/CXCR4 axis

The SDF-1/CXCR4 signaling plays a critical role in the trafficking of mesenchymal stem cells (MSCs) to the sites of tissue damage. Our recent study demonstrated that atorvastatin (ATV) treatment improved the survival of MSCs, and ATV pretreated MSCs (^ATV-MSCs) exhibited enhanced engraftment to injured myocardium. In this study, we investigated whether combined treatment with ATV and ^ATV-MSCs enhances cardiac repair and regeneration by activating SDF-1/CXCR4 signaling in a rat model of acute myocardial infarction. Rats were randomized into eight groups: the Sham, AMI control and 6 other groups that were subjected to AMI followed by treatment with MSCs, ATV, ATV+MSCs, ^ATV-MSCs, ATV+^ATV-MSCs, ATV+^ATV-MSCs+AMD3100 (SDF-1/CXCR4 antagonist), respectively. ATV+^ATV-MSCs significantly potentiated targeted recruitment of MSCs to peri-infarct myocardium and resulted in further improvements in cardiac function and reduction in scar size compared with MSCs treatment alone at 4-week after AMI. More importantly, the cardioprotective effects conferred by ATV+^ATV-MSCs were almost completely abolished by AMD3100 treatment. Together, our study demonstrated that ATV+^ATV-MSCs significantly enhanced the targeted recruitment and survival of transplanted MSCs, and resulted in subsequent cardiac function improvement by augmenting SDF-1/CXCR4 signaling.

Co-delivery of sorafenib and metapristone encapsulated by CXCR4-targeted PLGA-PEG nanoparticles overcomes hepatocellular carcinoma resistance to sorafenib

Background

Sorafenib is approved as a standard therapy for advanced hepatocellular carcinoma (HCC), but its clinical application is limited due to moderate therapeutic efficacy and high incidence of acquired resistance resulted from elevated levels of SDF-1/CXCR4 axis induced by prolonged sorafenib treatment. We previously demonstrated metapristone (RU486 metabolite) as a cancer metastatic chemopreventive agent targeting SDF-1/CXCR4 axis. Therefore, we hypothesized that combining sorafenib with metapristone could synergistically suppress cell proliferation, enhance anti-cancer activity and repress potential drug resistance.

Methods

Changes in cellular CXCR4 expression by metapristone were analyzed by RT-PCR and western blotting. Effect of combining sorafenib with metapristone on cell viability was examined by MTT assay; combination index value was calculated to evaluate the synergistic effect of combined therapy. To overcome poor pharmacokinetics and reduce off-target toxicity, CXCR4-targeted nanoparticles (NPs) were developed to co-deliver sorafenib and metapristone into CXCR4-expressing HCC in vitro and in vivo; cell proliferation, colony formation and apoptosis assays were conducted; nude mice bearing HCC xenograft were used to examine effects of this therapeutic approach on HCC progression.

Results

Here we showed metapristone significantly reduced CXCR4 expression in HCC. Combinatory chemotherapy of sorafenib with metapristone synergistically suppressed HCC proliferation and resistance. CXCR4-targeted PEGylated poly (lactic-co-glycolic acid) NPs conjugated with LFC131 (a peptide inhibitor of CXCR4), could deliver more sorafenib and metapristone into HCC via specific recognition and binding with transmembrane CXCR4, and resulted in the enhanced cytotoxicity, colony inhibition and apoptosis by regulating more Akt/ERK/p38 MAPK/caspase signaling pathways. Co-delivery of sorafenib with metapristone by the LFC131-conjugated NPs showed prolonged circulation and target accumulation at tumor sites, and thus suppressed tumor growth in a tumor xenograft model.

Conclusions

In conclusion, co-delivery of sorafenib and metapristone via the CXCR4-targeted NPs displays a synergistic therapy against HCC. Our results suggest combinational treatment of chemotherapeutics offer an effective strategy for enhancing the therapeutic efficacy on carcinoma, and highlight the potential application of ligand-modified tumor-targeting nanocarriers in delivering drugs as a promising cancer therapeutic approach.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1216-x) contains supplementary material, which is available to authorized users.

Blockade of SDF-1/CXCR4 reduces adhesion-mediated chemoresistance of multiple myeloma cells via interacting with interleukin-6

Resistance to chemotherapy represents a major cause for treatment failure in multiple myeloma (MM). Herein, this study was conducted to explore the effect of SDF-1/CXCR4 and interleukin-6 (IL-6) in MM cell adhesion-mediated chemoresistance. Enzyme-linked immunosorbent assay was applied to detect expressions of SDF-1α and IL-6 in MM patients and healthy controls. RPMI-8226 cells and isolated bone marrow stromal cells (BMSCs) were stimulated using recombinant SDF-1α and IL-6. Effect of cocultured BMSCs and RPMI-8226 cells on chemosensitivity and apoptosis of RPMI-8226 cells was analyzed. Effect of doxorubicin on the adhesion rate of RPMl-8226 cells to BMSCs was analyzed by calcitonin test. Effect of SDF-1α-induced upregulation of IL-6 on chemotherapeutic resistance and apoptosis of RPMI-8226 cells in adhesion state was analyzed. Cell adhesion model was treated with recombinant protein SDF-1α and phosphoinositide 3-kinase (P13K) inhibitor Wortmarmin. The levels of P13K and protein kinase B (AKT) and its phosphorylation as well as the expression of IL-6 were analyzed. SDF-1α was positively correlated with IL-6. Recombinant human SDF-1α increased IL-6 expression and induced IL-6 secretion in a time- and dose-dependent manner in BMSCs, which was inhibited by IL-6 and SDF-1α neutralizing antibodies. Coculture of MM cells with BMSCs increased the drug resistance and inhibited the apoptosis on MM cells. SDF-1α-induced IL-6 upregulation mediates chemoresistance and apoptosis of RPMI-8226 cells in adhesion state. SDF-1α may up-regulate the expression of IL-6 by activating the P13K/AKT signaling pathway. SDF-1/CXCR4 may up-regulate the expression of IL-6 through the activation of the P13K/AKT signaling pathway, thereby affecting the chemoresistance mediated by adhesion in MM cells.

Baicalin promotes apoptosis and inhibits proliferation and migration of hypoxia-induced pulmonary artery smooth muscle cells by up-regulating A2a receptor via the SDF-1/CXCR4 signaling pathway

Background

Baicalin is a flavonoid compound that exerts specific pharmacological effect in attenuating the proliferation, migration, and apoptotic resistance of hypoxia-induced pulmonary artery smooth muscle cells (PASMCs). However, the underlying mechanism has not been fully elucidated yet. Although our previous studies had indicated that activation of A2aR attenuates CXCR expression, little is known about the relationship between A2aR and SDF-1/CXCR4 axis in hypoxic PASMCs. In this study, we aimed to investigate the effect of A2aR on the SDF-1/CXCR4 axis in hypoxic PASMCs, the mechanism underlying this effect, and whether baicalin exerts its protective functions though A2aR.

Methods

Rat PASMCs were cultured under normoxia/hypoxia and divided into nine groups: normoxia, hypoxia, hypoxia + AMD3100 (a CXCR4 antagonist), hypoxia + baicalin, hypoxia + negative virus, normoxia + A2aR knockdown, hypoxia + A2aR knockdown, hypoxia + CGS21680 (an A2aR agonist), and hypoxia + A2aR knockdown + baicalin. Lentiviral transfection methods were used to establish the A2aR knockdown model in PASMCs. Cells were incubated under hypoxic conditions for 24 h. Expression levels of A2aR, SDF-1, and CXCR4 were detected using RT-qPCR and western blot. The proliferation and migration rate were observed via CCK-8 and Transwell methods. Cell cycle distribution and cell apoptosis were measured by flow cytometry (FCM) and the In-Situ Cell Death Detection kit (Fluorescein).

Results

Under hypoxic conditions, levels of A2aR, SDF-1, and CXCR4 were significantly increased compared to those under normoxia. The trend of SDF-1 and CXCR4 being inhibited when A2aR is up-regulated was more obvious in the baicalin intervention group. Baicalin directly enhanced A2aR expression, and A2aR knockdown weakened the function of baicalin. SDF-1 and CXCR4 expression levels were increased in the hypoxia + A2aR knockdown group, as were the proliferation and migration rates of PASMCs, while the apoptotic rate was decreased. Baicalin and CGS21680 showed opposite effects.

Conclusions

Our data indicate that baicalin efficiently attenuates hypoxia-induced PASMC proliferation, migration, and apoptotic resistance, as well as SDF-1 secretion, by up-regulating A2aR and down-regulating the SDF-1/CXCR4 axis.

Danhong Injection Enhances the Therapeutic Efficacy of Mesenchymal Stem Cells in Myocardial Infarction by Promoting Angiogenesis

Stem cell-based therapies have the potential to dramatically transform the treatment and prognosis of myocardial infarction (MI), and mesenchymal stem cells (MSCs) have been suggested as a promising cell population to ameliorate the heart remodeling in post-MI. However, poor implantation and survival in ischemic myocardium restrict its efficacy and application. In this study, we sought to use the unique mode of action of Chinese medicine to improve this situation. Surrounding the myocardial infarct area, we performed a multi-point MSC transplantation and administered in conjunction with Danhong injection, which is mainly used for the treatment of MI. Our results showed that the MSC survival rate and cardiac function were improved significantly through the small animal imaging system and echocardiography, respectively. Moreover, histological analysis showed that MSC combined with DHI intervention significantly reduced myocardial infarct size in myocardial infarcted mice and significantly increased MSC resident. To investigate the mechanism of DHI promoting MSC survival and cell migration, PCR and WB experiments were performed. Our results showed that DHI could promote the expression of CXC chemokine receptor 4 in MSC and enhance the expression of stromal cell–derived factor-1 in myocardium, and this effect can be inhibited by AMD3100 (an SDF1/CXCR4 antagonist). Additionally, MSC in combination with DHI interfered with MI in mice and this signifies that when combined, the duo could the expression of vascular endothelial growth factor (VEGF) in the marginal zone of infarction compared with when either MSC or DHI are used individually. Based on these results, we conclude that DHI enhances the residence of MSCs in cardiac tissue by modulating the SDF1/CXCR4 signaling pathway. These findings have important therapeutic implications for Chinese medicine-assisted cell-based therapy strategies.

Notch signaling plays a crucial role in cancer stem-like cells maintaining stemness and mediating chemotaxis in renal cell carcinoma

Background

Cancer stem cells (CSCs) are correlated with the initiation, chemoresistance and relapse of tumors. Notch pathway has been reported to function in CSCs maintenance, but whether it is involved in renal cell carcinoma (RCC) CSCs maintaining stemness remain unclear. This study aims to explore the effect of Notch pathway on stemness of CSCs in RCC and the underlying mechanisms.

Methods

The CD133⁺/CD24⁺ cells were isolated from RCC ACHN and Caki-1 cell line using Magnetic-activated cell sorting and identified by Flow cytometry analysis. RT-PCR and immunoblot analyses were used for determining the stemness maker expression. The effect of Notch pathway on function of CSCs was assessed by self-renewal ability, chemosensitivity, invasive and migratory ability tumorigenicity in vivo using soft agar colony formation assay, sphere-forming assay, MTT assay, Transwell assay.

Results

Here, we found that the sorted CD133⁺/CD24⁺cells possessed elevated stemness maker CTR2, BCL-2, MDR1, OCT-4, KLF4, compared with parental cells, as well as enhanced self-renewal ability, stronger resistance to cisplatin and sorafenib, increased invasion and migration, and higher tumorigenesis in vivo, suggesting the CD133⁺/CD24⁺ cells have the stem-like characteristics of CSCs and thus identified as RCC CSCs. Then the enhanced notch1, notch2, Jagged1, Jagged2, DLL1 and DLL4 expression were detected in RCC CSCs and blockage of Notch1 or notch2 using pharmacological inhibitor MRK-003 or its endogenous inhibitor Numb resulted in loss of its stemness features: self-renewal, chemoresistance, invasive and migratory potential, and tumorigenesis in vivo. Moreover, it is confirmed that overexpression of notch1 up-regulated CXCR4 inRCC CSCs and augmented SDF-1-induced chemotaxis in RCC CSCs in vitro, which could be rescued when treatment of CXCR4 inhibitor, suggesting that notch signaling promotes the chemotaxis of RCC CSCs by SDF-1/CXCR4 axis.

Conclusions

Our results provide a new mechanism of RCC CSCs maintaining stemness via notch pathway as well as a potential therapeutic target in human RCC.

Injectable hydrogel delivery plus preconditioning of mesenchymal stem cells: exploitation of SDF-1/CXCR4 axis toward enhancing the efficacy of stem cells' homing

Clinical applications of mesenchymal stem cells (MSCs) rely on their capacity to home and engraft in the appropriate target injury tissues for the long term. However, their homing efficiency has been observed to be very poor because of the lack or modifications of homing factors SDF-1α and CXCR4 receptors. Hence, this study was designed to investigate the homing and retention of pretreated human adipose tissue-derived MSCs (hASCs) from three different delivery routes in response to SDF-1α, released from chitosan-based injectable hydrogels. After stimulation of ASCs with a hypoxia mimicking agent, the expression level and functionality of CXCR4 were analyzed by flowcytometric analysis (FACS), transwell migration assay and qPCR. Then, the homing/retention of pretreated DiI-labeled hASCs were compared through three different in vivo delivery routes, 2 weeks after transplantation in Wistar rats. The cells were tracked histologically by fluorescent microscope and by PCR for human-specific CXCR4 gene. Results showed CXCR4 has dynamic expression pattern and pretreatment of hASCs significantly up-regulates CXCR4, leading to an increase in migration capacity toward 100 ng/mL SDF-1α in vitro and homing into the subcutaneously implanted hydrogel releasing SDF-1α in vivo. Furthermore, it seems that SDF-1α is particularly important in the retention of ASCs, in addition to its chemoattraction role. In summary, the delivery route in which the ASCs were mixed with the hydrogel rather than systemic delivery and local injection and preconditioning undertaken to increase CXCR4 expression concomitant with SDF-1α delivery by the injectable hydrogel, allowed for further homing/retention of ASCs. This might be a promising way to get better therapeutic outcomes in stem cell therapy.

EphA1 activation promotes the homing of endothelial progenitor cells to hepatocellular carcinoma for tumor neovascularization through the SDF-1/CXCR4 signaling pathway

BACKGROUND

Endothelial progenitor cells (EPCs) can migrate to the tumor tissue and enhance the angiogenesis of hepatocellular carcinoma (HCC); thus, they are associated with a poor prognosis. However, the specific molecular mechanism underlying the homing of EPCs to the HCC neovasculature remains unrevealed.

METHODS

Co-culture experiments of endothelial progenitor cells with HCC cells with modulation of EphA1 were performed in vitro. Using EPCs as angiogenic promoters by injecting them into HCC xenograft-bearing nude mice via their tail veins to test homing ability of EPCs changed according to different EphA1 level in HCC xenograft.

RESULTS

In this study, we found that the up-regulation of EphA1 expression in HCC cells could affect not only the chemotaxis of EPCs to tumor cells and endothelial cells (ECs) but also the tube formation ability of EPCs in a paracrine fashion. Further, we revealed that the increased expression of EphA1 in HCC cells led to an increased SDF-1 concentration in the tumor microenvironment, which in turn activated the SDF-1/CXCR4 axis and enhanced the recruitment of EPCs to HCC. In addition, the EphA1-activated SDF-1 expression and secretion was partially mediated by the PI3K and mTOR pathways. In vivo experiments demonstrated that blocking EphA1/SDF-1/CXCR4 signaling significantly inhibited the growth of HCC xenografts. Using immunohistochemistry and immunofluorescence assays, we verified that the inhibition of tumor angiogenesis was at least partially caused by the decreased number of EPCs homing to tumor tissue.

CONCLUSIONS

Our findings indicate that targeting the EphA1/SDF-1 signaling pathway might be a therapeutic anti-angiogenesis approach for treating HCC.

AMD3100 and G-CSF disrupt the cross-talk between leukemia cells and the endosteal niche and enhance their sensitivity to chemotherapeutic drugs in biomimetic polystyrene scaffolds

BACKGROUND

The multidrug resistance of leukemia cells is closely related to the microenvironment. The present leukemia microenvironment models focus on two-dimensional co-culture system in vitro which does not mimic the in vivo cell growth, while the 3D polystyrene (PS) scaffolds have the advantage. Stromal cell derived factor-1 may be involved in the shielding of endosteal niche from leukemia cells by binding to its receptor CXCR4, but the relationship between SDF-1/CXCR4 axis and leukemia cells is unclear.

DESIGN AND METHODS

The experiments were built on the 3D PS scaffolds coated with osteoblasts. Stromal cells and MV4-11 cells were plated on the scaffolds. Then G-CSF, AMD3100 and cytarabine were added. Adhesive rate, SDF-1 level, migration state, apoptosis rate, and cell cycle of leukemia cells were observed after incubation at 24h and 48h.

RESULTS

G-CSF decreased the level of SDF-1 and inhibited the expression of CXCR4 and promoted stationary phase leukemia cells to enter the mitotic phase and enhanced the killing effect of chemotherapeutic drugs. AMD3100 disrupted the interaction between tumors and matrix, mobilized the leukemia cells to keep away from the protective microenvironment and strengthened the cytotoxic effect of Ara-C. The combination of G-CSF and AMD3100 had stronger effects on killing the leukemia cells induced by Ara-C.

CONCLUSION

It demonstrates that AMD3100 and G-CSF may inhibit adhesion and migration abilities of leukemia cells with the bone marrow niche. Both of them inhibit the role of SDF-1/CXCR4 directly or indirectly. Thus inhibiting SDF-1/CXCR4 axis may be helpful to the treatment of refractory AML.

Are there any new insights for G-CSF and/or AMD3100 in chemotherapy of haematological malignants?

AML is a common life-threatening blood system malignancy. The treatment of AML continues to face greater challenges. An abnormal haematopoietic niche with high adhesion and proliferation might be the root cause of resistance and relapse. Most leukaemia cells are stored in the endosteal niche and recess in the G0 phase, and they are not sensitive to varieties of radiotherapies and chemotherapies. G-CSF and AMD3100 are increasingly used in priming chemotherapy. G-CSF can promote leukaemia cells to the cell cycle, which improves the complete remission rate of leukaemia patients. AMD3100, the novel CXCR4 antagonist, could also potentially promote leukaemia cells to cell cycle and improve the susceptibility of leukaemia cells to chemotherapeutic agents. The combination of them enhances anti-leukaemia effect. So in this review, we explore the function of G-CSF and/or AMD3100 in the priming chemotherapy of haematological malignants.

The role of SDF-1/CXCR4 in the vasculogenesis and remodeling of cerebral arteriovenous malformation

Background

Cerebral arteriovenous malformation (AVM) involves the vasculogenesis of cerebral blood vessels and can cause severe intracranial hemorrhage. Stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, are believed to exert multiple physiological functions including angiogenesis. Thus, we investigated the role of SDF-1/CXCR4 in the vasculogenesis of cerebral AVM.

Methods

Brain AVM lesions from surgical resections were analyzed for the expression of SDF-1, CXCR4, VEGF-A, and HIF-1 by using immunohistochemical staining. Flow cytometry was used to quantify the level of circulating endothelial progenitor cells (EPCs). Further, in an animal study, chronic cerebral hypoperfusion model rats were analyzed for the expression of SDF-1 and HIF-1. CXCR4 antagonist, AMD3100, was also used to detect its effects on cerebral vasculogenesis and SDF-1 expression.

Results

Large amounts of CXCR4-positive CD45⁺ cells were found in brain AVM lesion blood vessel walls, which also have higher SDF-1 expression. Cerebral AVM patients also had higher level of EPCs and SDF-1. In chronic cerebral hypoperfusion rats, SDF-1, HIF-1, and CD45 expressions were elevated. The application of AMD3100 effectively suppressed angiogenesis and infiltration of CXCR4-positive CD45⁺ cells in hypoperfusion rats compared to controls.

Conclusion

The SDF-1/CXCR4 axis plays an important role in the vasculogenesis and migration of inflammatory cells in cerebral AVM lesions, possibly via the recruitment of bone marrow EPCs.

SDF-1/CXCR4 Axis Regulates Cell Cycle Progression and Epithelial-Mesenchymal Transition via Up-regulation of Survivin in Glioblastoma

Stromal cell-derived factor 1 (SDF-1)/CXCR4 ligand-receptor axis is widely recommended as an attractive target for cancer therapy. Meanwhile, epithelial-mesenchymal transition (EMT) process is linked to disease pathophysiology. As one of inhibitors of apoptosis proteins, survivin is implicated in the onset and development of cancer. In the present study, we tried to determine the cause-effect associations between SDF-1/CXCR4 axis and survivin expression in glioblastoma U-251 cell line. Survivin activation and inhibition were induced with exogenous SDF-1 and survivin small interfering RNA (survivin siRNA), respectively. Western blot was used to detect relevant proteins in SDF-1/CXCR4 axis. Western blot analysis revealed that survivin expression in U-251 increased in a dose- and time-dependent manner in response to SDF-1 treatment. However, the interference with MEK/ERK and PI3K/AKT pathway prohibited SDF-1-induced survivin up-regulation. Importantly, survivin knockdown abrogated cell cycle progression and the expression of snail and N-cadherin, compared with non-transfectants. In conclusion, the present study shows that SDF-1 up-regulates survivin via MEK/ERK and PI3K/AKT pathway, leading to cell cycle progression and EMT occurrence dependent on survivin. The blockade of survivin will allow for the treatment of glioblastoma.

CD138-negative myeloma cells regulate mechanical properties of bone marrow stromal cells through SDF-1/CXCR4/AKT signaling pathway

As the second most prevalent hematologic malignancy, multiple myeloma (MM) remains incurable and relapses due to intrinsic or acquired drug resistance. Therefore, new therapeutic strategies that target molecular mechanisms responsible for drug resistance are attractive. Interactions of tumor cells with their surrounding microenvironment impact tumor initiation, progression and metastasis, as well as patient prognosis. This cross-talk is bidirectional. Tumor cells can also attract or activate tumor-associated stromal cells by releasing cytokines to facilitate their growth, invasion and metastasis. The effect of myeloma cells on bone marrow stromal cells (BMSCs) has not been well studied. In our study, we found that higher stiffness of BMSCs was not a unique characteristic of BMSCs from MM patients (M-BMSCs). BMSCs from MGUS (monoclonal gammopathy of undetermined significance) patients were also stiffer than the BMSCs from healthy volunteers (N-BMSCs). The stiffness of M-BMSCs was enhanced when cocultured with myeloma cells. In contrast, no changes were seen in myeloma cell-primed MGUS- and N-BMSCs. Interestingly, our data indicated that CD138⁻ myeloma cells, but not CD138⁺ cells, regulated M-BMSC stiffness. SDF-1 was highly expressed in the CD138⁻ myeloma subpopulation compared with that in CD138⁺ cells. Inhibition of SDF-1 using AMD3100 or knocking-down CXCR4 in M-BMSCs blocked CD138⁻ myeloma cells-induced increase in M-BMSC stiffness, suggesting a crucial role of SDF-1/CXCR4. AKT inhibition attenuated SDF-1-induced increases in M-BMSC stiffness. These findings demonstrate, for the first time, CD138⁻ myeloma cell-directed cross-talk with BMSCs and reveal that CD138⁻ myeloma cells regulate M-BMSC stiffness through SDF-1/CXCR4/AKT signaling.

Transplanted hUCB-MSCs migrated to the damaged area by SDF-1/CXCR4 signaling to promote functional recovery after traumatic brain injury in rats

Transplanted human umbilical cord mesenchymal stem cells (hUC-MSCs) have exhibited considerable therapeutic potential for traumatic brain injury (TBI). However, how hUC-MSCs migrating to the injury region and the mechanism of hUC-MSCs promoting functional recovery after TBI are still unclear. In this study, we investigated whether stromal cell-derived factor-1 (SDF-1) was involved in the hUC-MSCs migration and the possible mechanisms that might be involved in the beneficial effect on functional recovery. In vitro experiments demonstrated that SDF-1 induces a concentration-dependent migration of hUC-MSCs. Furthermore, pre-treatment with the CXCR4-specific antagonist AMD3100 significantly prevented the migration of hUC-MSCs in vitro. We found that the expression of SDF-1 increased significantly around the damaged area. Transplanted hUC-MSCs were localized to regions where SDF-1 was highly expressed. Additionally, our results showed that hUC-MSCs-treated animals showed significantly improved functional recovery compared with controls. In hUC-MSCs-transplanted group, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells were decreased and BrdU-positive cells were significantly increased compared with control group, more of BrdU-positive cells co-localized with GFAP. These suggest that SDF-1 plays an important role in the migration of hUC-MSCs to the damaged area and hUC-MSCs are beneficial for functional recovery after TBI.

Regulation of high mobility group box 1 and hypoxia in the migration of mesenchymal stem cells

Mesenchymal stem cells (MSCs) have been increasingly offered for tissue regeneration with the premise that they can survive and thrive amidst the microenvironment of injured or degenerate tissues. The role of high mobility group box 1 (HMGB1) and hypoxia in the proliferation and migration of rat bone marrow MSCs (rBM-MSCs) has been investigated. First, the effect of HMGB1 on the proliferation of rBM-MSCs was determined. Second, to evaluate the regulation of hypoxia and HMGB1 in the migration of rBM-MSCs, cells in the wound healing model were exposed to four conditions: normoxia (20% O2) and complete medium, normoxia and HMGB1, hypoxia (1% O2) and complete medium, hypoxia and HMGB1. RT-PCR and Western blotting were used to measure the expression of migration-related genes and proteins. HMGB1 inhibited the proliferation of rBM-MSCs; HMGB1 alone or together with hypoxia and promoted the migration of MSCs and upregulated the expression of HIF-1α and SDF-1. These results demonstrated that HMGB1 arrested the proliferation of rBM-MSCs, but enhanced the migration of rBM-MSCs which could be further improved by hypoxia. This study strengthens current understanding of the interaction between MSCs and the microenvironment of damaged tissues.