The granulocyte macrophage–colony stimulating factor surface modified MB49 bladder cancer stem cells vaccine against metastatic bladder cancer

The Bladder Tumor Microenvironment Components That Modulate the Tumor and Impact Therapy

The tumor microenvironment (TME) is complex and involves many different cell types that seemingly work together in helping cancer cells evade immune monitoring and survive therapy. The advent of single-cell sequencing has greatly increased our knowledge of the cell types present in the tumor microenvironment and their role in the developing cancer. This, coupled with clinical data showing that cancer development and the response to therapy may be influenced by drugs that indirectly influence the tumor environment, highlights the need to better understand how the cells present in the TME work together. This review looks at the different cell types (cancer cells, cancer stem cells, endothelial cells, pericytes, adipose cells, cancer-associated fibroblasts, and neuronal cells) in the bladder tumor microenvironment. Their impact on immune activation and on shaping the microenvironment are discussed as well as the effects of hypertensive drugs and anesthetics on bladder cancer.

GM-CSF: A Double-Edged Sword in Cancer Immunotherapy

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine that drives the generation of myeloid cell subsets including neutrophils, monocytes, macrophages, and dendritic cells in response to stress, infections, and cancers. By modulating the functions of innate immune cells that serve as a bridge to activate adaptive immune responses, GM-CSF globally impacts host immune surveillance under pathologic conditions. As with other soluble mediators of immunity, too much or too little GM-CSF has been found to promote cancer aggressiveness. While too little GM-CSF prevents the appropriate production of innate immune cells and subsequent activation of adaptive anti-cancer immune responses, too much of GM-CSF can exhaust immune cells and promote cancer growth. The consequences of GM-CSF signaling in cancer progression are a function of the levels of GM-CSF, the cancer type, and the tumor microenvironment. In this review, we first discuss the secretion of GM-CSF, signaling downstream of the GM-CSF receptor, and GM-CSF’s role in modulating myeloid cell homeostasis. We then outline GM-CSF’s anti-tumorigenic and pro-tumorigenic effects both on the malignant cells and on the non-malignant immune and other cells in the tumor microenvironment. We provide examples of current clinical and preclinical strategies that harness GM-CSF’s anti-cancer potential while minimizing its deleterious effects. We describe the challenges in achieving the Goldilocks effect during administration of GM-CSF-based therapies to patients with cancer. Finally, we provide insights into how technologies that map the immune microenvironment spatially and temporally may be leveraged to intelligently harness GM-CSF for treatment of malignancies.

Advances in Liver Cancer Stem Cell Isolation and their Characterization

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.

Targeted Delivery of Therapeutics to Urological Cancer Stem Cells

Urological cancer refers to cancer in organs of the urinary system and the male reproductive system. It mainly includes prostate cancer, bladder cancer, renal cancer, etc., seriously threatening patients' survival. Although there are many advances in the treatment of urological cancer, approved targeted therapies often result in tumor recurrence and therapy failure. An increasing amount of evidence indicated that cancer stem cells (CSCs) with tumor-initiating ability were the source of treatment failure in urological cancer. The development of CSCstargeted strategy can provide a possibility for the complete elimination of urological cancer. This review is based on a search of PubMed, Google scholar and NIH database (http://ClinicalTrials.gov/) for English language articles containing the terms: "biomarkers", "cancer stem cells", "targeting/targeted therapy", "prostate cancer", bladder cancer" and "kidney cancer". We summarized the biomarkers and stem cell features of the prostate, bladder and renal CSCs, outlined the targeted strategies for urological CSCs from signaling pathways, cytokines, angiogenesis, surface markers, elimination therapy, differentiation therapy, immunotherapy, microRNA, nanomedicine, etc., and highlighted the prospects and future challenges in this research field.

Antitumor efficacy of interferon-γ-modified exosomal vaccine in prostate cancer

BACKGROUND

Exosomes secreted by tumor cells can be regarded as carriers of tumor-associated antigens and have potential value in tumor immunotherapy. The aim of this study was to evaluate the antitumor efficacy of a novel exosomal vaccine (interferon-γ [IFN-γ]-modified exosomal vaccine) in prostate cancer.

METHODS

Prostate cancer cell-derived exosomes were used to prepare the exosomal vaccine using our protein-anchoring technique. The immunogenicity and therapeutic efficacy of the exosomes was evaluated by measuring the effects of the exosomal vaccine on M1 macrophage differentiation, the ability of macrophages to engulf the exosomes, the production of antibodies against exosomes, and tumor angiogenesis and metastasis, and tumor growth.

RESULTS

The IFN-γ fusion protein was efficiently anchored on the surface of prostate cancer cell-derived exosomes and retained its bioactivity. The IFN-γ-exosomal vaccine increased the number of M1 macrophages, enhanced the ability of M1 macrophages to engulf RM-1 cell-derived exosomes, and induced the production of specific antibodies against exosomes. The exosomal vaccine downregulated the expression of vascular endothelial growth factor receptor 2 and attenuated the effect of exosomes in promoting tumor metastasis. The proportions of CD4⁺ , CD8⁺ , and IFN-γ⁺ CD8⁺ T cells in the exosomal vaccine group were the highest among the four groups. Interestingly, the IFN-γ-exosomal vaccine decreased the percentage of Tregs and downregulated the expression of programed death-ligand 1 and indoleamine 2, 3-dioxygenase 1 in the tumor environment. The exosomal vaccine significantly inhibited tumor growth and prolonged the survival time of mice with prostate cancer. The exosomal and tumor cell vaccines had a good synergistic effect in promoting tumor immunity.

CONCLUSIONS

The novel exosomal vaccine induced an immune response that cleared prostate cancer cell-derived exosomes, thereby eliminating the regulatory effect of the exosomes. This study may provide experimental evidence for the use of exosomes as a therapeutic tool or target in immunotherapy for human prostate cancer.

Dual Inhibition of Pirarubicin-Induced AKT and ERK Activations by Phenformin Sensitively Suppresses Bladder Cancer Growth

Activations of Akt or ERK pathway induced by clinical drugs promote therapeutic failure due to decrease of drug response, and no available strategies have been developed to solve these problems. In this study, we found that pirarubicin (THP), one important chemotherapeutic drug for treating bladder cancer intravesically, dramatically elevated phosphorylations of both Akt and Erk1/2 in addition to inducing DNA damage. MK2206 or AZD6244, representative Akt and Erk1/2 inhibitors, respectively, profoundly sensitized bladder cancer cells to THP treatment. Interestingly, we found that inhibition of a single arm of either Akt or Erk1/2 pathway would induce the increase of another arm, indicating the existence of the crosstalk between these two pathways. Thus, simultaneous suppression of both signals may be needed for increasing the sensitivity of THP. On the other hand, we revealed that phenformin efficiently inhibited both Akt and Erk1/2 phosphorylation in a dose-dependent manner. Furthermore, we demonstrated that phenformin, mimicking dual inhibitors, plays dramatically synergistic action with THP both in vitro and in vivo. Our findings suggest that combination therapy of THP with dual inhibitors may constitute a successful strategy for improving chemotherapy response.

Cancer stem cells as a therapeutic target in bladder cancer

Bladder cancer is one of the most prevalent genitourinary cancers responsible for about 150,000 deaths per year worldwide. Currently, several treatments, such as endoscopic and open surgery, appended by local or systemic immunotherapy, chemotherapy, and radiotherapy are used to treat this malignancy. However, the differences in treatment outcome among patients suffering from bladder cancer are considered as one of the important challenges. In recent years, cancer stem cells, representing a population of undifferentiated cells with stem-cell like properties, have been eyed as a major culprit for the high recurrence rate in superficial papillary bladder cancer. Cancer stem cells have been reported to be resistant to conventional treatments, such as chemotherapy, radiation, and immunotherapy, which induce selective pressure on tumoral populations resulting in selection and growth of the resistant cells. Therefore, targeting the therapeutic aspects of cancer stem cells in bladder cancer may be promising. In this study, we briefly discuss the biology of bladder cancer and then address the possible relationship between molecular biology of bladder cancer and cancer stem cells. Subsequently, the mechanisms of resistance applied by cancer stem cells against the conventional therapeutic tools, especially chemotherapy, are discussed. Moreover, by emphasizing the biomarkers described for cancer stem cells in bladder cancer, we have provided, described, and proposed targets on cancer stem cells for therapeutic interventions and, finally, reviewed some immunotargeting strategies against bladder cancer stem cells.

Clearance of HBeAg and HBsAg of HBV in mice model by a recombinant HBV vaccine combined with GM-CSF and IFN-α as an effective therapeutic vaccine adjuvant

Chronic hepatitis B virus (CHB) infection is a significant public threat. Current interferon-α (IFN-α) based therapies and anti-viral drugs have failed to clear the infection in the majority of CHB patients and animal models. In our previous study, we established a combined protocol that employed a 3-day pretreatment with granulocyte-macrophage colony stimulating factor (GM-CSF) prior to a standard HBV vaccine. It achieved a 90% reduction of HBsAg level in the HBsAg transgenic mouse model. This protocol, while effective, remains too complex for clinical use. In this study, we formulated a new regimen by combining GM-CSF, IFN-α and a recombinant HBV vaccine (GM-CSF/IFN-α/VACCINE) into a single preparation and tested its efficacy in a HBV infection model. After four vaccinations, both serum HBeAg and HBsAg were cleared, accompanied by a 95% reduction of HBV⁺ hepatocytes and the presence of a large number of infiltrating CD8⁺ T cells in the liver. Mechanistically these robust responses were initiated by a vaccine-induced conversion of CCR2-dependent CD11b⁺Ly6C^hi monocytes into CD11b⁺CD11c⁺ DCs. This finding sheds light on the potential mechanism of action of the GM-CSF-based vaccine adjuvant and provides definable markers for clinical assessment during future testing of such highly potent vaccine protocols in HBV patients.

LncRNA XIST/miR-200c regulates the stemness properties and tumourigenicity of human bladder cancer stem cell-like cells

Background

The abnormal expression of non-coding RNAs (ncRNAs), such as microRNAs and long ncRNAs, often contribute to the development of cancers. miR-200c functions as a tumour suppressor that impacts the growth of bladder cancer cells and the epithelial-to-mesenchymal transition (EMT). LncRNA X inactive specific transcript (XIST) is highly expressed in tumour tissues, promotes cancer progression and might act as an miRNA molecular sponge. This study aimed to examine the relationship between lncRNA XIST and miR-200c and to assess their functions in the regulation of the stemness properties and tumourigenicity of human bladder cancer stem cell (BCSC)-like cells.

Methods

Biological effects including cell clone formation, sphere formation, self-renewal properties and mouse tumourigenesis were examined in BCSC-like cells with miR-200c overexpression or XIST knockdown. Real-time PCR and western blotting were used to detect the expression changing of related factors in BCSC-like cells gene models. Dual luciferase reporter assay was used to examine the changes of XIST and miR-200c expression levels.

Results

The results indicated that miR-200c overexpression and XIST knockdown could inhibit cell clone formation, self-renewal ability and EMT in BCSC-like cells. miR-200c knockdown could restore the tumour growth inhibition caused by XIST knockdown.

Conclusion

LncRNA XIST may act as an inhibitor of miR-200c to regulate the stemness properties and tumourigenicity of bladder cancer cells, and our findings might reveal a potential strategy of targeting XIST for bladder cancer therapy.

Down-regulation of PKM2 enhances anticancer efficiency of THP on bladder cancer

Pyruvate kinase M2 (PKM2) regulates the final step of glycolysis levels that are correlated with the sensitivity of anticancer chemotherapeutic drugs. THP is one of the major drugs used in non‐muscle‐invasive bladder cancer instillation chemotherapy. However, low response ratio of THP (19.7%) treatment to human genitourinary tumours using collagen gel matrix has been observed. This study aims to investigate the effect of down‐regulation of PKM2 on THP efficiency. Via inhibitor or siRNA, the effects of reduced PKM2 on the efficiency of THP were determined in 2 human and 1 murine bladder cancer cell lines, using MTT, cologenic and fluorescence approaches. Molecular mechanisms of PKM2 on THP sensitization were explored by probing p‐AMPK and p‐STAT3 levels via WB. Syngeneic orthotopic bladder tumour model was applied to evaluate this efficiency in vivo, analysed by Kaplan‐Meier survival curves, body and bladder weights plus immunohistochemistric tumour biomarkers. PKM2 was overexpressed in bladder cancer cells and tissues, and down‐regulation of PKM2 enhanced the sensitivity of THP in vitro. Activation of AMPK is essential for THP to exert anti‐bladder cancer activities. On the other hand, down‐regulating PKM2 activates AMPK and inhibits STAT3, correlated with THP sensitivity. Compared with THP alone (400 μmol L⁻¹, 50 μL), the combination with metformin (60 mmol L⁻¹, 50 μL) stopped growth of bladder cancer completely in vivo (combination group VS normal group P = .078). Down‐regulating the expression of PKM2 enhances the anticancer efficiency of THP. This study provides a new insight for improving the chemotherapeutic effect of THP.

PD-1/PD-L1 blockade enhances the efficacy of SA-GM-CSF surface-modified tumor vaccine in prostate cancer

Program death receptor-1 (PD-1)/program death ligand 1 (PD-L1) signaling plays an important role in tumor adaptive immune resistance. The streptavidin-granulocyte-macrophage colony stimulating factor (SA-GM-CSF) surface-modified tumor cells vaccine developed through our novel protein-anchor technology could significantly promote the activation of dendritic cells. Although GM-CSF vaccine could significantly increase the number of tumor-specific CD8⁺T-cells, the majority of these CD8⁺T-cells expressed PD-1. Moreover, GM-CSF vaccine up-regulated the PD-L1 expression of tumor cells, resulting in immune resistance. Adding PD-1/PD-L1 blockade to GM-CSF vaccine therapy could significantly increase the population of CD4⁺ T, CD8⁺ T and CD8⁺ IFN-γ⁺ T but not CD4⁺ Foxp3⁺ T-cells and induced the highest production of IFN-γ. PD-1/PD-L1 blockade could effectively rescue the tumor-specific T lymphocytes generated by the GM-CSF vaccine, resulting in consistent tumor rejection. Taken together, PD-1/PD-L1 blockade combined with SA-GM-CSF-modified vaccine could effectively induce a strong specific antitumor immune response against prostate cancer.

[S100A4, a potential therapeutic target on bladder cancer stem cells]

OBJECTIVE

To observe the effect of S100A4 gene silencing mediated by small interfering RNA (siRNA) on the proliferation of bladder cancer stem cells (CSCs) and their capacity of xenograft tumor formation.

METHODS

MB49 bladder cancer stem cells (MCSCs) were isolated and identified. The differentially expressed protein S100A4 was identified in MCSCs using isobaric tags for relative and absolute quantitation technology (iTRAQ). A siRNA targeting S100A4 was constructed and transfected into MCSCs, and its inhibitory effects on S100A4 expression in MCSCs were assessed with Western blotting and qPCR. The effects of siRNA-mediated S100A4 silencing on the proliferation and xenograft tumor formation ability of MCSCs were observed.

RESULTS

Among the 65 differentially expressed proteins identified by iTRAQ combined with LC/MS/MS, S100A4 protein showed the most distinct differential expression in MCSCs. Transfection of MCSCs with S100A siRNA significantly inhibited the expressions of S100A4 at both mRNA and protein levels, caused obvious suppression of the cell proliferation, and attenuated the xenograft tumor formation ability of the cells in nude mice.

CONCLUSION

S100A4 in MCSCs is associated with the recurrence and metastasis of bladder cancer. S100A4 may serve as a potential therapeutic target for eliminating bladder CSCs.

A modified method by differential adhesion for enrichment of bladder cancer stem cells

Purpose:

In a previous study the vaccine was effective against bladder cancer in a mouse model. However, a small portion of tumors regrew because the vaccine could not eliminate bladder cancer stem cells (CSCs). In this study, we showed a modified method for the isolation of bladder CSCs using a combination of differential adhesion method and serum-free culture medium (SFM) method.

Materials and Methods:

Trypsin-resistant cells and trypsin-sensitive cells were isolated from MB49, EJ and 5637 cells by a combination of differential adhesion method and SFM method. The CSCs characterizations of trypsin-resistant cells were verified by the flow cytometry, the western blotting, the quantitative polymerase chain reaction, the resistance to chemotherapy assay, the transwell assay, and the tumor xenograft formation assay.

Results:

Trypsin-resistant cells were isolated and identified in CSCs characters, with high expression of CSCs markers, higher resistance to chemotherapy, greater migration in vitro, and stronger tumorigenicity in vivo.

Conclusion:

Trypsin-resistant cells displayed specific CSCs properties. Our study showed trypsin-resistant cells were isolated successfully with a modified method using a combination of differential adhesion method and SFM method.

Self-assembled tumor-targeting hyaluronic acid nanoparticles for photothermal ablation in orthotopic bladder cancer

Bladder cancer is one of the most frequent malignancies in the urinary system. Radical cystectomy is inevitable when bladder cancer progresses to a muscle-invasive disease. However, cystectomy still causes a high risk of death and a low quality of life (such as ureter-abdomen ostomy, uroclepsia for ileal-colon neobladder). Therefore, more effective treatments as well as bladder preservation are needed. We developed self-assembled tumor-targeting hyaluronic acid-IR-780 nanoparticles for photothermal ablation in over-expressing CD44 (the receptor for HA) bladder cancer, which show high tumor selectivity, high treatment efficacy, good bioavailability, and excellent biocompatibility. The nanoparticles demonstrated a stable spherical nanostructure in aqueous conditions with good mono-dispersity, and their average size was 171.3±9.14nm. The nanoparticles can be degraded by hyaluronidase when it is over-expressed in bladder cells; therefore, they appear to have a hyaluronidase-responsive "OFF/ON" behavior of a fluorescence signal. HA-IR-780 NPs also showed high photothermal efficiency; 2.5, 5, 10 and 20μg/mL of NPs had a maximum temperature increase of 11.2±0.66°C, 18.6±0.75°C, 26.8±1.11°C and 32.3±1.42°C. The in vitro cell viability showed that MB-49 cells could be efficiently ablated by combining HA-IR-780 NPs with 808nm laser irradiation. Then, in vivo biodistribution showed the HA-IR-780 NPs are targeted for accumulation in bladder cancer cells but have negligible accumulation in normal bladder wall. The photothermal therapeutic efficacy of HA-IR-780 NPs in the orthotopic bladder cancer model showed tumors treated with NPs had a maximum temperature of 48.1±1.81°C after 6min of laser irradiation. The tumor volume was approximately 65-75mm³ prior to treatment. After 12days, the tumor sizes for the PBS, PBS plus laser irradiation and HA-IR-780 NPs-treated groups were 784.75mm³, 707.5mm³, and 711.37mm³, respectively. None of the tumors in the HA-IR-780 NPs plus laser irradiation-treated group were visible to the naked eye. A toxicity study showed HA-IR-780 NPs (2.5-20mg/kg, i.v.) were nontoxic and safe for in vivo applications. HA-IR-780 nanoparticles address current clinical challenges, treating locally aggressive lesions and preserving the bladder. They have enormous potential to improve the bladder cancer treatment strategies in clinic.

STATEMENT OF SIGNIFICANCE

1) Bladder cancer is one of the most frequent malignancies in the urinary system. Radical cystectomy is inevitable while bladder cancer progress to muscle-invasive disease. 2) We developed self-assembled tumor-targeting hyaluronic acid-IR-780 nanoparticles for photothermal ablation in over-expressing CD44 (the receptor for HA) bladder cancer. 3) Photothermal therapeutic efficacy of HA-IR-780 NPs in orthotopic bladder cancer model showed tumors were completely ablated. 4) HA-IR-780 nanoparticles address current clinical challenges, treating locally aggressive lesions as well as for bladder preservation.

Immunotherapy against metastatic bladder cancer by combined administration of granulocyte macrophage-colony stimulating factor and interleukin-2 surface modified MB49 bladder cancer stem cells vaccine

In previous studies, it has been shown that the granulocyte macrophage‐colony stimulating factor (GM‐CSF) or interleukin‐2 (IL‐2) surface modified MB49 bladder cancer stem cells (MCSCs) vaccine could induce a specific antitumor immunity and against bladder cancer in mice model respectively. However, whether combined administration of GM‐CSF and IL‐2 could produce specific immune responses to cancer stem cells (CSCs) was uncertain. MCSCs were established and characterized. GM‐CSF and IL‐2 MCSCs vaccines were prepared and bioactivity was evaluated. The therapeutic, protective, specific, and memorial immune response animal experiments were designed. Tumor‐specific cytotoxic T lymphocytes assay, enzyme linked immunosorbent assay, flow cytometry assay were performed to indentify whether vaccine caused an antitumor immunity. Streptavidin (SA)‐GM‐CSF and SA‐IL‐2 MCSCs vaccines were prepared successfully. Such vaccines inhibited the volume of tumor and prolonged the survival of the mice in animal experiments. The express of IgG or IFN‐c, the portion of dendritic cells, CD8⁺ and CD4⁺ T cells were highest in the combined vaccines group than the SA‐GM‐CSF vaccine group, the SA‐IL‐2 vaccine group, the MCSCs group and the PBS group. The combined of GM‐CSF and IL‐2 vaccines could induce better antitumor immunity than a vaccine alone.

High efficacy of intravesical treatment of metformin on bladder cancer in preclinical model

Anticancer potential of metformin has been extensively studied. However, its anticancer clinical use remains yet to be approved since sufficient concentration on target organs could not be achieved via conventional administration. To overcome this drawback, we aim to examine the efficiency of novel intravesical treatment of metformin on syngeneic orthotopic preclinical model. Three human and one murine bladder cancer cell lines were tested in vitro for inhibitory sensitivity by MTT and cologenic assays. AMPK pathway including AKT, Erk and S6K was examined by western blot and further explored by regulating activated levels using specific inhibitors. In vivo efficacy was determined by Kaplan-Meier survival curves and measurements of body and bladder weights plus tumor biomarkers. Lactic acid and metformin levels of plasma were measured by standard procedures. The results demonstrated that metformin activated AMPK and decreased phosphorylation of Akt and Erk. Furthermore, combinations of metformin with either Akt or Erk inhibitors synergistically diminished cancer proliferation, suggesting the involvement of Akt- and Erk- related pathways. Intravesical metformin 26 and 104 mg/kg, twice per week demonstrated a rapid elimination of the implanted tumor without any evidence of toxicity. In contrast, oral treatment at a dose of 800mg/kg/d exhibited little efficacy whereas severe toxicity existed if the dosage is higher. Collectively, intravesical metformin displays potent inhibition on bladder cancer in vitro and this preclinical study reveals the profound therapeutic application of metformin with durable tolerance via intravesical administration route.

Vesigenurtacel-L (HS-410) in the management of high-grade nonmuscle invasive bladder cancer

Unlike other malignancies, the death rate of bladder cancer has not declined in several decades, highlighting the need for new treatment options. In the emerging era of immunotherapy, therapeutic cancer vaccines are an attractive option to cure, control and prevent cancer. Despite this, finding a feasible and efficacious vaccine platform has proven elusive across all malignancies. Vesigenurtacel-L is the first whole cell, allogeneic vaccine intended to treat high-grade, nonmuscle invasive bladder cancer. This type of vaccine technology for bladder cancer is novel, and has the potential to be both economically and logistically feasible.

The promotion of the transformation of quiescent gastric cancer stem cells by IL-17 and the underlying mechanisms

Postoperative recurrence and metastasis have crucial roles in the poor prognosis of gastric cancer patients. Previous studies have indicated that gastric cancer originates from cancer stem cells (CSCs), and some investigators have found that a particular subset of CSCs possesses higher metastatic capacity. However, the specific mechanism remains uncertain. In the present study, we aimed to explore the biological functions of the inflammatory cytokine interleukin-17 (IL-17) in gastric cancer metastasis and the distinct IL-17-induced transformation of quiescent gastric CSCs. Our results showed that invasive gastric CSCs were CD26+ and CXCR4+ and were closely associated with increased metastatic ability. The quiescent gastric CSCs, which were CD26- and CXCR4-, were exposed to appropriate concentrations of IL-17; this resulted in the decreased expression of E-cadherin and the increased expression of vimentin and N-cadherin. In addition, the upregulation of IL-17 both in vitro and in vivo resulted in a significant induction of invasion, migration and tumor formation ability in gastric CSCs compared with the control group, which was not treated with IL-17. Further experiments indicated that the activation of the downstream phosphorylated signal transducer and activator of transcription 3 (STAT3) transcription factor pathway was facilitated by IL-17. On the contrary, the downregulation of STAT3 by the specific inhibitor Stattic significantly reversed the IL-17-induced epithelial-mesenchymal transition (EMT)-associated properties of quiescent gastric CSCs. Moreover, tumorigenesis and metastasis were suppressed. Taken together, we suggest that IL-17 is positively correlated with the transformation of quiescent gastric CSCs into invasive gastric CSCs and that targeting IL-17 may emerge as a possible novel therapeutic strategy for gastric cancer.

Silencing expression of the NANOG gene and changes in migration and metastasis of urinary bladder cancer cells

INTRODUCTION

It has been proved that expression of the NANOG gene is observed not only in embryonic-derived malignancies, but also in breast cancer, ovarian cancer, cervix cancer and bladder cancer. NANOG overexpression is correlated with high activity of MMP-2 and MMP-9. The aim of the study was to evaluate the changes in the malignant phenotype of T24 bladder cancer cells with modulated expression of the NANOG gene.

MATERIAL AND METHODS

Human urinary bladder cancer cells T24 (HTB-4) were cultivated under standard conditions. Transfection of the cells with silencing constructions was performed with the application of Lipofectamine 2000 (Invitrogen) reagent. Evaluation of changes in the expression level of individual genes was performed using qRTPCR. Changes in the protein level were evaluated using the Human ELISA Kit (Abcam). The invasion capability of transfected cells was tested using Matrigel Invasion Chambers (BD Biosciences). The changes in cell migration were assessed with a wound-healing assay.

RESULTS

The qRTPCR evaluation showed that silencing the NANOG gene in T24 cells led to the decrease of mRNA for the MMP-2 gene to the level of 62.4% and the MMP-9 gene to the level of 76%. The cells with modulated expression of the NANOG gene migrated slower in the Matrigel invasion assay and in the wound-healing assay. The immunoenzymatic test showed a decrease in the protein level of MMP-9.

CONCLUSIONS

The transcriptional activity of the NANOG gene might be connected with some aspects of bladder cancer cell metastasis in vitro and has an influence on MMP-2 and MMP-9 expression levels.

Metformin and gefitinib cooperate to inhibit bladder cancer growth via both AMPK and EGFR pathways joining at Akt and Erk

EGFR is a potential therapeutic target for treating bladder cancer, but has not been approved for clinical use yet. Metformin is a widely used antidiabetic drug and has demonstrated interesting anticancer effects on various cancer models, alone or in combination with chemotherapeutic drugs. The efficacy of gefitinib, a well-known EGFR tyrosine kinase inhibitor, combined with metformin was assessed on bladder cancer and underlying mechanisms were explored. This drug combination induced a strong anti-proliferative and anti-colony forming effect and apoptosis in bladder cancer cell lines. Gefitinib suppressed EGFR signaling and inhibited phosphorylation of ERK and Akt. Metformin amplified this inhibitory effect and enhanced gefitinib-induced activation of AMPK signaling pathway. In vivo intravesical treatment of metformin and gefitinib on syngeneic orthotopic mice confirmed the significant inhibitory effect on bladder tumor growth. These two drugs may be an excellent combination for the treatment of bladder cancer through intravesical instillation.

Future directions in bladder cancer immunotherapy: towards adaptive immunity

The clinical management of bladder cancer has not changed significantly in several decades. In particular, intravesical bacillus Calmette-Guérin (BCG) immunotherapy has been a mainstay for high-risk nonmuscle invasive bladder cancer since the late 1970s/early 1980s. This is despite the fact that bladder cancer has the highest recurrence rates of any cancer and BCG immunotherapy has not been shown to induce a tumor-specific immune response. We and others have hypothesized that immunotherapies capable of inducing tumor-specific adaptive immunity are needed to impact bladder cancer morbidity and mortality. This article summarizes the preclinical and clinical development of bladder cancer immunotherapies with an emphasis on the last 5 years. Expected progress in the near future is also discussed.

Effect of salinomycin on metastasis and invasion of bladder cancer cell line T24

OBJECTIVE

To explore the effect of salinomycin on the metastasis and invasion of bladder cancer cell line T24 by regulating the related protein expression in the process of epithelial-mesenchymal transition (EMT), and to provide experimental basis for the treatment of urological tumors.

METHODS

The bladder cancer cell line T24 was cultured in vitro. The rat bladder tumor model was established in vivo. The rats were randomized into two groups, among which the rats in the experiment group were given intraperitoneal injection of salinomycin, while the rats in the control group were given intraperitoneal injection of normal saline. The change of tumor cells in the two groups was observed. Transwell was used to detect the cell migration and invasion abilities, Real-time PCR was used to detect the expression of mRNA, while Western-blot was utilized for the determination of the expressions of E-cadherin and vimentin proteins.

RESULTS

The metastasis and invasion abilities of serum bladder cancer cell line T24 after salinomycin treatment in the experiment group were significantly reduced when compared with those in the control group, and the tumor metastasis lesions were decreased from an average of 1.59 to 0.6 (P < 0.05). T24 cell proliferation in the experiment group was gradually decreasing. T24 cell proliferation at 48 h was significantly lower than that at 12 h and 24 h (P < 0.05). T24 cell proliferation at 24 h was significantly lower than that at 12 h (P < 0.05). T24 cell proliferation at each timing point in the experiment group was significantly lower than that in the control group (P < 0.05). The serum mRNA level and E-cadherin expression in the tumor tissues in the experiment group were significantly higher than those in the control group, while vimentin expression level was significantly lower than that in the control group (P < 0.05).

CONCLUSIONS

Salinomycin can suppress the metastasis and invasion of bladder cancer cells, of which the mechanism is probably associated with the inhibition of EMT of tumor cells.