CXCR3/CXCR3 ligand biological axis impairs RENCA tumor growth by a mechanism of immunoangiostasis

Metastatic renal cell carcinoma (RCC) responds poorly to chemo- or radiation therapy but appears to respond to systemic immunotherapy (i.e., IL-2 and/or IFN-alpha), albeit with only 5-10% durable response. The CXCR3/CXCR3 ligand biological axis plays an important role in mediating type 1 cytokine-dependent cell-mediated immunity, which could be beneficial for attenuating RCC if optimized. We found that systemic IL-2 induced the expression of CXCR3 on circulating mononuclear cells but impaired the CXCR3 ligand chemotactic gradient from plasma to tumor by increasing circulating CXCR3 ligand levels in a murine model of RCC. Moreover, the antitumor effect of systemic IL-2 was CXCR3-dependent, as IL-2 failed to inhibit tumor growth and angiogenesis in CXCR3-/- mice. We hypothesized that the immunotherapeutic effect of the CXCR3/CXCR3 ligand biological axis could be optimized by first priming with systemic IL-2 to induce CXCR3 expression on circulating mononuclear cells followed by enhancing the intratumor CXCR3 ligand levels to establish optimal CXCR3-dependent chemotactic gradient. We found that combined systemic IL-2 with an intratumor CXCR3 ligand (CXCL9) lead to significantly greater reduction in tumor growth and angiogenesis, increased tumor necrosis, and increased intratumor infiltration of CXCR3+ mononuclear cells, as compared with either IL-2 or CXCL9 alone. The enhanced antitumor effect of the combined strategy was associated with a more optimized CXCR3-dependent chemotactic gradient and increased tumor-specific immune response. These data suggest that the combined strategy of systemic IL-2 with intratumor CXCR3 ligand is more efficacious than either strategy alone for reducing tumor-associated angiogenesis and augmenting tumor-associated immunity, the concept of immunoangiostasis.     

Differential role of CD133 and CXCR4 in renal cell carcinoma

The chemokine receptor CXCR4 and CD133, putative stem cell markers, were previously described in renal cancer (RCC). To evaluate the biological and prognostic role of CD133 and CXCR4 in RCC the expression was evaluated through qPCR and immunoblotting in human renal cancer cell lines (786-O, A498, ACHN, CAKI-1, SN12C, TK10, UO31) and patients biopsies. Renal cancer cells and surgical biopsies expressed functional CXCR4 while CD133 was not detectable. CXCR4 and CD133 expression was then evaluated in 240 renal cancer patients through immunohistochemistry. CXCR4 and CD133 were low in 19.1% and 59.6%; intermediate in 20% and 17.9%; high in 60.8% and 22.5% of the cases, respectively. CXCR4 was overexpressed in tumours (p= 0.02), while CD133 was over expressed in healthy tissues (p= 0.04). Disease free survival Kaplan Meier plots suggest that prognosis is unfavourable for patients whose primary tumours express CXCR4 (p= 0.0199) but nor CD133 (p= 0.151) neither the concomitant CXCR4-CD133 (p=0.848) high expression affected prognosis. Analysis of prognostic factors suggests that age, clinical presentation, AJCC stage and CXCR4 had a significant prognostic value at the univariate analysis. The CXCR4 predictive ability was confirmed at the multivariate analysis while no prognostic role was identified for CD133. Thus concomitant CD133 and CXCR4 evaluation is not worth in RCC patient while the CXCR4 prognostic role encourage CXCR4 antagonists as promising therapeutic option.     

CXCR2/CXCR2 ligand biology during lung transplant ischemia-reperfusion injury

Lung transplantation is a therapeutic option for a number of end-stage pulmonary disorders. Early lung allograft dysfunction (ischemia-reperfusion injury) continues to be the most common cause of early mortality after lung transplantation and a significant risk factor for the development of bronchiolitis obliterans syndrome. Ischemia-reperfusion injury is characterized histopathologically by lung edema and a neutrophil predominate leukocyte extravasation. The specific mechanism(s) that recruit leukocytes to the lung during post-lung transplantation ischemia-reperfusion injury have not been fully elucidated. Because the ELR+ CXC chemokines are potent neutrophil chemoattractants, we investigated their role during post-lung transplantation ischemic-reperfusion injury. We found elevated levels of multiple ELR+ CXC chemokines in human bronchoalveolar lavage fluid from patients with ischemia-reperfusion injury. Proof of concept studies using a rat orthotopic lung transplantation model of "cold" ischemic-reperfusion injury demonstrated an increase in lung graft neutrophil sequestration and injury. In addition, lung expression of CXCL1, CXCL2/3, and their shared receptor CXCR2 paralleled lung neutrophil infiltration and injury. Importantly, inhibition of CXCR2/CXCR2 ligand interactions in vivo led to a marked reduction in lung neutrophil sequestration and graft injury. Taken together these experiments support the notion that increased expression of ELR+ CXC chemokines and their interaction with CXCR2 plays an important role in the pathogenesis of post-lung transplantation cold ischemia-reperfusion injury.     

The role of SDF-1-CXCR4/CXCR7 axis in biological behaviors of adipose tissue-derived mesenchymal stem cells in vitro

Numerous studies have reported that CXCR4 and CXCR7 play an essential, but differential role in stromal cell-derived factor-1 (SDF-1)-inducing cell chemotaxis, viability and paracrine actions of BMSCs. Adipose tissue-derived mesenchymal stem cells (ADSCs) have been suggested to be potential seed cells for clinical application instead of bone marrow derived stroma cell (BMSCs). However, the function of SDF-1/CXCR4 and SDF-1/CXCR7 in ADSCs is not well understood. This study was designed to analyze the effect of SDF-1/CXCR4 and SDF-1/CXCR7 axis on ADSCs biological behaviors in vitro. Using Flow cytometry and Western blot methods, we found for the first time that CXCR4/CXCR7 expression was increased after treatment with SDF-1 in ADSCs. SDF-1 promoted ADSCs paracrine, proliferation and migration abilities. CXCR4 or CXCR7 antibody suppressed ADSCs paracrine action induced by SDF-1. The migration of ADSCs can be abolished by CXCR4 antibody, while the proliferation of ADSCs was only downregulated by CXCR7 antibody. Our study indicated that the angiogenesis of ADSCs is, at least partly, mediated by SDF-1/CXCR4 and SDF-1/CXCR7 axis. However, only binding of SDF-1/CXCR7 was required for proliferation of ADSCs, and CXCR7 was required for migration of ADSCs induced by SDF-1. Our studies provide evidence that the activation of either axis may be helpful to improve the effectiveness of ADSCs-based stem cell therapy.     

The role of calmodulin in human renal cell carcinoma

Calmodulin is a ubiquitous intracellular calcium binding protein which has been shown to be associated with cell cycling. Previous studies using animal tumor models have suggested a positive correlation between tumor calmodulin content and rate of tumor growth. We studied the role of calmodulin in renal cell carcinoma (RCC) cell lines and compared this with short term normal fetal kidney cell lines. The effects of calmodulin inhibition was determined using the calmodulin inhibitor W13 (Naphthalene-sulfonamide) and its less active partner W12. Cell size, calmodulin content and inhibition studies using W13 did not reveal any simple correlations for the RCC cell lines, although the RCC lines did have a higher content than the fetal kidney cell lines. Calmodulin content determination of RCC and normal adult kidney tissue failed to show any difference. We conclude that, contrary to previous reports using animal models, there is no simple relationship between tumor growth rates and calmodulin content for human RCC.     

Osteopontin enhances the expression and activity of MMP-2 via the SDF-1/CXCR4 axis in hepatocellular carcinoma cell lines

Background and Aims

Osteopontin, SDF-1α, and MMP-2 are important secreted molecules involved in the pathophysiology of human hepatocellular carcinoma (HCC). This study investigates the effect of the SDF-1α/CXCR4 axis on expression and activity of MMP-2 induced by osteopontin.

Methods

The expression of CXCR4, SDF-1α, MMP-2 and their associated cellular signaling cascades, involving Akt and MAP Kinases, were determined by Western blotting. The activities of MMP-2 and MMP-9 were assayed by gel zymography. The role of the osteopontin receptors integrin α_vβ₃ and CD44v6 was evaluated using neutralizing antibodies. We also established CXCR4-deficient SMMC7721 cell lines by transfection with miRNA-CXCR4 plasmids and determined cell invasion activity in a transwell assay.

Results

In comparison with untreated cells, recombinant human osteopontin (rhOPN) up-regulated CXCR4, SDF-1α, and MMP-2 expression about 5-, 4-, and 6-fold on the protein levels through binding to integrin α_vβ₃ and CD44v6 in hepatocellular carcinoma cells (SMMC7721 and HepG2). Inhibition of the SDF-1α/CXCR4 axis down-regulated the rhOPN-induced MMP-2 expression and activity. rhOPN also activated Akt, p38 and JNK. Down-regulation of CXCR4 decreased the rhOPN-induced invasion in SMMC7721 cells.

Conclusion

These results indicate that rhOPN up-regulates MMP-2 through the SDF-1α/CXCR4 axis, mediated by binding to integrin α_vβ₃ and CD44v6 and activating the PI-3K/Akt and JNK pathways in HepG2 and SMMC7721 cells. Therefore, the osteopontin-SDF-1α/CXCR4-MMP-2 system may be a new therapeutic target for treating HCC progression.     

The emerging role of small non-coding RNA in renal cell carcinoma

Noncoding RNAs are transcribed in the most regions of the human genome, divided into small noncoding RNAs (less than 200 nt) and long noncoding RNAs (more than 200 nt) according to their size. Compelling evidences suggest that small noncoding RNAs play critical roles in tumorigenesis and tumor progression, especially in renal cell carcinoma. MiRNA, the most famous small noncoding RNA, has been comprehensively explored for its fundamental role in cancer. And several miRNA-based therapeutic strategies have been applied to several ongoing clinical trials. However, piRNAs and tsRNAs, have not received as much research attention, because of several technological limitations. Nevertheless, some studies have revealed the presence of aberration of piRNAs and tsRNAs in renal cell carcinoma, highlighting a potentially novel mechanism for tumor onset and progression. In this review, we provide an overview of three classes of small noncoding RNA: miRNAs, piRNAs and tsRNAs, that have been reported dysregulation in renal cell carcinoma and have the potential for advancing diagnosis, prognosis and therapeutic applications of this disease.     

The role of SDF-1-CXCR4/CXCR7 axis in the therapeutic effects of hypoxia-preconditioned mesenchymal stem cells for renal ischemia/reperfusion injury

In vitro hypoxic preconditioning (HP) of mesenchymal stem cells (MSCs) could ameliorate their viability and tissue repair capabilities after transplantation into the injured tissue through yet undefined mechanisms. There is also experimental evidence that HP enhances the expression of both stromal-derived factor-1 (SDF-1) receptors, CXCR4 and CXCR7, which are involved in migration and survival of MSCs in vitro, but little is known about their role in the in vivo therapeutic effectiveness of MSCs in renal ischemia/reperfusion (I/R) injury. Here, we evaluated the role of SDF-1-CXCR4/CXCR7 pathway in regulating chemotaxis, viability and paracrine actions of HP-MSCs in vitro and in vivo. Compared with normoxic preconditioning (NP), HP not only improved MSC chemotaxis and viability but also stimulated secretion of proangiogenic and mitogenic factors. Importantly, both CXCR4 and CXCR7 were required for the production of paracrine factors by HP-MSCs though the former was only responsible for chemotaxis while the latter was for viability. SDF-1α expression was upregulated in postischemic kidneys. After 24 h systemical administration following I/R, HP-MSCs but not NP-MSCs were selectively recruited to ischemic kidneys and this improved recruitment was abolished by neutralization of CXCR4, but not CXCR7. Furthermore, the increased recruitment of HP-MSCs was associated with enhanced functional recovery, accelerated mitogenic response, and reduced apoptotic cell death. In addition, neutralization of either CXCR4 or CXCR7 impaired the improved therapeutic potential of HP-MSCs. These results advance our knowledge about SDF-1-CXCR4/CXCR7 axis as an attractive target pathway for improving the beneficial effects of MSC-based therapies for renal I/R.     

The role of the CXCR4/CXCL12 axis and its clinical implications in gastric cancer

Gastric cancer is the second leading cause of cancer deaths worldwide. Despite the extensive body of research on gastric cancer, the prognosis of patients with advanced gastric cancer remains poor, and therapy for advanced gastric cancer relies largely on cytotoxic chemotherapy. Therefore, identifying the distinct molecular pathways underlying disease progression and treatment resistance may lead to novel therapeutic approaches, as well as improve the quality of life and survival of patients. The chemokine CXCL12 and its receptor CXCR4 are now known to play an important role in cancer development and progression. Here, we review the expression and function of CXCR4 and CXCL12, as well as their clinical relevance in gastric cancer. We also cover the current molecular mechanism, specifically the cell-signaling pathway, by which gastric cancer progresses through the CXCR4/CXCL12 axis, and discuss the potential of that axis as a therapeutic target in the treatment of gastric cancer.     

CXCL12/CXCR4/CXCR7轴在子宫内膜异位症中的研究进展

子宫内膜异位症(endometriosis, EMT)是常见的妇科疾病,发病率高,且有年轻化的趋势。因其治疗困难且复发率高,严重影响了女性的生活质量和生育能力。研究发现趋化因子CXCL12与其受体CXCR4和CXCR7在恶性肿瘤中起重要作用。虽然EMT为良性疾病,但有恶性肿瘤的生物学特征,近来发现CXCL12/CXCR4/CXCR7轴可以影响子宫内膜异位症的定植、侵袭和转移。本文就当前国内外研究CXCL12/CXCR4/CXCR7轴在EMT发生发展过程中的作用进行了综述,旨在为EMT的治疗找到新靶点。     

The role of CXCR3 and its ligands in renal transplant outcome

Chemokines and their corresponding receptors serve as pro-inflammatory and migratory signals for immune cells. CXCR3 and its corresponding ligands, CXCL9, CXCL10 and CXCL11, participate in the induction of immune responses against several foreign antigens. Numerous cells, including macrophages, NK cells and T lymphocytes, express CXCR3 and thus, expression of the receptor and its ligands can induce activity of these important immune cells against foreign antigens, including allogeneic grafts. Several parameters of the immune system participate in the induction and stimulation of powerful immune responses against allogeneic grafts. A thorough understanding of the parameters that regulate these responses can provide insights into new methods for immunotherapy during organ transplantation. The aim of this review is to address the most recent information regarding the roles played by CXCR3 and its corresponding ligands in the outcome of renal transplantation.     

The role of HMGB1-RAGE axis in migration and invasion of hepatocellular carcinoma cell lines

High mobility group protein box1 (HMGB1) and its receptor—receptor for advanced glycation end products (RAGE) are pivotal factors in the development and progression of many types of tumor, but the role of HMGB1-RAGE axis in hepatocellular carcinoma (HCC) especially its effects on metastasis and recurrence remains obscure. Here, we report the role of HMGB1-RAGE axis in the biological behaviors of HCC cell lines and the underlying molecular mechanism. We show that the expressions of HMGB1, RAGE, and extracellular HMGB1 increase consistently according to cell metastasis potentials, while the concentration of soluble form of RAGE (sRAGE) is inversely related to metastasis potential of HCC cells. Furthermore, our data show that rhHMGB1 promotes cellular proliferation, migration, and invasion, and increases the level of nuclear factor kappa B (NF-κB), while administrations of HMGB1-siRNA, RAGE-siRNA, anti-HMGB1 neutralizing antibody, anti-RAGE neutralizing antibody, and sRAGE inhibit cellular proliferation, migration, and invasion. Moreover, we also demonstrate that the expression of NF-кB is inhibited by knockdown of HMGB1 or RAGE. Collectively, these data demonstrate that HMGB1 activates RAGE signaling pathways and induces NF-кB activation to promote cellular proliferation, invasion, and metastasis, in HCC cell lines. Taken together, HMGB1-RAGE axis may become a potential target in HCC therapy.