Role of stromal cell-derived factor 1α pathway in bone metastatic prostate cancer

Molecular landscape of prostate cancer bone metastasis

Prostate cancer (PC) has a high propensity to develop bone metastases, causing severe pain and pathological fractures that profoundly impact a patients' normal functions. Current clinical intervention is mainly palliative focused on pain management, and tumor progression is refractory to standard therapeutic regimens. This limited treatment efficacy is at least partially due to a lack of comprehensive understanding of the molecular landscape of the disease pathology, along with the intensive overlapping of physiological and pathological molecular signaling. The niche is overwhelmed with diverse cell types with inter- and intra-heterogeneity, along with growth factor-enriched cells that are supportive of invading cell proliferation, providing an additional layer of complexity. This review seeks to provide molecular insights into mechanisms underlying PC bone metastasis development and progression.

Melittin Prevents Metastasis of Epidermal Growth Factor-Induced MDA-MB-231 Cells through The Inhibition of The SDF-1α/CXCR4 Signaling Pathway

Objective

Melittin is one of the natural components of bee venom (Apis mellifera), and its anticancer and antimetastatic properties have been well established, but the underlying mechanism remains elusive. The MDA-MB-231 is a triplenegative cell line that is highly aggressive and invasive. Besides, many critical proteins are involved in tumor invasion and metastasis. In this study, we investigated whether melittin inhibits the migration and metastasis of epidermal growth factor (EGF)-induced MDA-MB-231 cells via the suppression of SDF-1α/CXCR4 and Rac1-mediated signaling pathways.

Materials and Methods

In this experimental study, cells were treated with melittin (0.5-4 μg/ml), and the toxicity of melittin was assessed by the MTT assay. Afterward, the migration assay was conducted to measure the degree of the migration of EGF-induced cells. The western blot technique was performed to analyze the rate of Rac1, p-Rac1, SDF- 1α, and CXCR4 expression in different groups.

Results

The results demonstrated that melittin markedly suppressed the migration of EGF-induced cells and decreased the expression of p-Rac1, CXCR4, and SDF-1α proteins.

Conclusion

The results of the present study suggested that the anti-tumor properties of melittin could be through the blocking of the SDF-1α/CXCR4 signaling pathway, which is beneficial for the reduction of tumor migration and invasion.

Anlotinib Combined With Anti-PD-1 Antibodies Therapy in Patients With Advanced Refractory Solid Tumors: A Single-Center, Observational, Prospective Study

Introduction

Anlotinib (AL3818) is a novel multi-target tyrosine kinase inhibitor (TKI) targeting vascular endothelial growth factor receptor (VEGFR) and suppressing tumor growth. Modulation of tumor suppressive immune microenvironment via the inhibition of vascular endothelial growth factor may augment the activity of immune checkpoint inhibitors. Here we described the results of safety, and clinical efficacy of anlotinib combined with immunotherapy in patients with advanced solid tumors, the serum cytokine levels, and peripheral blood T lymphocyte populations were detected simultaneously.

Methods

Twenty six cases with advanced late-stage cancers including lung, gallbladder, endometrial, gastric, pancreatic, penile cancers and melanoma were treated since January 2019. Patients received a combination of anlotinib (12mg) once daily on day 1 to day 14 (21 days as a course) plus anti-PD-1 antibodies every 3 weeks until progression or intolerable toxicity. Imaging was performed every 6 weeks for the first year of therapy. Blood samples were collected from patients prospectively. Serum interleukin (IL)-2, IL-4, IL-6, IL-10, Tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and circulating immune cell subsets were measured at baseline and after two cycles of treatment via flow cytometry.

Results

There were ten tumor types enrolled with lung, gallbladder, cholangiocarcinoma and soft tissue sarcoma being the most common. Most patients had received front line treatments for metastatic disease (80.8%). The objective response rate (ORR) was 23.1%, including one complete response (CR) (3.8%) and five partial responses (PR) (19.2%) and a disease control rate (DCR=CR+PR+SD) of 80.8% (21 of 26). The median PFS was 8.37 months (95% CI: 6.5-10.0 months). Three patients (11.5%) had grade 3 treatment-related adverse events. There were no grade 4 or 5 treatment-related adverse events. Grades 3 toxicities included hand-foot syndrome (n=2) and hypertension (n=1). Higher serum IL-2, IL-4, IL-10, TNF-α, IFN-γ levels and lower ratios of CD4/CD8 T cells were found in the responders compared with non-responders.

Conclusions

The preliminary data showed that the combination of anlotinib and anti-PD-1 antibodies demonstrated promising durable antitumor efficacy with acceptable toxicity in patients with various advance tumors, and promoted favorable changes in serum IL-2, IL-4, IL-10, TNF-α, IFN-γ levels and circulating immune cell subsets in clinical responders. It is worth to further validate the efficacy in a randomized prospective trial.

Blood Platelets as an Important but Underrated Circulating Source of TGFβ

When treating diseases related primarily to tissue remodeling and fibrosis, it is desirable to regulate TGFβ concentration and modulate its biological effects. The highest cellular concentrations of TGFβ are found in platelets, with about 40% of all TGFβ found in peripheral blood plasma being secreted by them. Therefore, an understanding of the mechanisms of TGFβ secretion from platelets may be of key importance for medicine. Unfortunately, despite the finding that platelets are an important regulator of TGFβ levels, little research has been carried out into the development of platelet-directed therapies that might modulate the TGFβ-dependent processes. Nevertheless, there are some very encouraging reports suggesting that platelet TGFβ may be specifically involved in cardiovascular diseases, liver fibrosis, tumour metastasis, cerebral malaria and in the regulation of inflammatory cell functions. The purpose of this review is to briefly summarize these few, extremely encouraging reports to indicate the state of current knowledge in this topic. It also attempts to better characterize the influence of TGFβ on platelet activation and reactivity, and its shaping of the roles of blood platelets in haemostasis and thrombosis.

Cytokines and Chemokines as Mediators of Prostate Cancer Metastasis

The consequences of prostate cancer metastasis remain severe, with huge impact on the mortality and overall quality of life of affected patients. Despite the convoluted interplay and cross talk between various cell types and secreted factors in the metastatic process, cytokine and chemokines, along with their receptors and signaling axis, constitute important factors that help drive the sequence of events that lead to metastasis of prostate cancer. These proteins are involved in extracellular matrix remodeling, epithelial-mesenchymal-transition, angiogenesis, tumor invasion, premetastatic niche creation, extravasation, re-establishment of tumor cells in secondary organs as well as the remodeling of the metastatic tumor microenvironment. This review presents an overview of the main cytokines/chemokines, including IL-6, CXCL12, TGFβ, CXCL8, VEGF, RANKL, CCL2, CX3CL1, IL-1, IL-7, CXCL1, and CXCL16, that exert modulatory roles in prostate cancer metastasis. We also provide extensive description of their aberrant expression patterns in both advanced disease states and metastatic sites, as well as their functional involvement in the various stages of the prostate cancer metastatic process.

Interactions between cancer cells and bone microenvironment promote bone metastasis in prostate cancer

Bone metastasis is the leading cause of death in prostate cancer patients, for which there is currently no effective treatment. Since the bone microenvironment plays an important role in this process, attentions have been directed to the interactions between cancer cells and the bone microenvironment, including osteoclasts, osteoblasts, and bone stromal cells. Here, we explained the mechanism of interactions between prostate cancer cells and metastasis-associated cells within the bone microenvironment and further discussed the recent advances in targeted therapy of prostate cancer bone metastasis. This review also summarized the effects of bone microenvironment on prostate cancer metastasis and the related mechanisms, and provides insights for future prostate cancer metastasis studies.

Ovarian Tumor Microenvironment Signaling: Convergence on the Rac1 GTPase

The tumor microenvironment for epithelial ovarian cancer is complex and rich in bioactive molecules that modulate cell-cell interactions and stimulate numerous signal transduction cascades. These signals ultimately modulate all aspects of tumor behavior including progression, metastasis and therapeutic response. Many of the signaling pathways converge on the small GTPase Ras-related C3 botulinum toxin substrate (Rac)1. In addition to regulating actin cytoskeleton remodeling necessary for tumor cell adhesion, migration and invasion, Rac1 through its downstream effectors, regulates cancer cell survival, tumor angiogenesis, phenotypic plasticity, quiescence, and resistance to therapeutics. In this review we discuss evidence for Rac1 activation within the ovarian tumor microenvironment, mechanisms of Rac1 dysregulation as they apply to ovarian cancer, and the potential benefits of targeting aberrant Rac1 activity in this disease. The potential for Rac1 contribution to extraperitoneal dissemination of ovarian cancer is addressed.

Nonhuman primate model of persistent erectile and urinary dysfunction following radical prostatectomy: Feasibility of minimally invasive therapy

OBJECTIVE

Persistent urinary incontinence (UI) and/or erectile dysfunction (ED) occur in 30-50% of post-radical prostatectomy patients regardless of nerve sparing approaches. Identification of potential treatment options for these patients will require testing in an animal model that develops these chronic conditions. The objective was to characterize a nonhuman primate (NHP) model of persistent post-prostatectomy ED and UI and then test the feasibility of periurethral injection of the chemokine CXCL-12.

METHODS

Ten adult male cynomolgus monkeys were used. Two were used for study of normal male nonhuman primate genitourinary anatomy. Five were used for measures of sexual behavior, peak intra-corporal pressure (ICP), abdominal leak point pressures (ALPP) 3 and 6-months post open radical prostatectomy (ORP). Three additional ORP animals received ultrasound-guided peri-urethral injection of chemokine CXCL12 6 weeks after ORP, and UI/ED evaluated for up to 3 months.

RESULTS

The anatomy, innervation, and vascular supply to the prostate and surrounding tissues of these male NHPs are substantially similar to those of human beings. ORP resulted in complete removal of the prostate gland along with both neurovascular bundles and seminal vesicles while permitting stable restoration of vesico-urethral patency. ORP produced sustained (6 months) decreases in ALPP, ICP's, and sexual function. Transurethral injection of chemokine CXCL12 was feasible and had beneficial effects on erectile and urinary function.

CONCLUSIONS

ORP in NHPs produced persistent erectile and urinary tract dysfunction. Periurethral injection of CXCL-12 was feasible and improved both urinary incontinence and erectile dysfunction and suggests that this model can be used to test new approaches for both conditions.

Cancer-Specific Inhibitory Effects of Genetically Engineered Stem Cells Expressing Cytosine Deaminase and Interferon-β Against Choriocarcinoma in Xenografted Metastatic Mouse Models

Cancer treatments using stem cells expressing therapeutic genes have been identified for various types of cancers. In this study, we investigated inhibitory effects of HB1.F3.CD and HB1.F3.CD.IFN-β cells expressing Escherichia coli cytosine deaminase (CD) and human interferon-β (IFN-β) genes in intravenously (i.v.) injected mice with a metastasis model. In this treatment, pro-drug 5-fluorocytosine (5-FC) is converted to cytotoxic drug 5-fluorouracil by hNSCs expressing the CD gene, which inhibits DNA synthesis in cancer cells. Moreover, IFN-β induces apoptosis and reduces the growth of cancer cells. Upon MTT assay, proliferation of choriocarcinoma (JEG-3) cells decreased when co-cultured with hNSCs expressing CD and IFN-β genes. To confirm the cancer-tropic effect of these stem cells, chemoattractant factors (VEGF, CXCR4, and C-kit) secreted from JEG-3 cells were identified by polymerase chain reaction. hNSCs migrate toward JEG-3 cells due to ligand-receptor interactions of these factors. Accordingly, the migration capability of hNSCs toward JEG-3 cells was confirmed using an in vitro Trans-well assay, in vivo subcutaneously (s.c.) injected mice groups (xenograft model), and metastasis model. Intravenously injected hNSCs migrated freely to other organs when compared to s.c. injected hNSCs. Thus, we confirmed the inhibition of lung and ovarian metastasis of choriocarcinoma by i.v. injected HB1.F3.CD or HB1.F3.CD.IFN-β cells in the presence of 5-FC. Treatment of these stem cells also increased the survival rates of mice. In conclusion, this study showed that metastatic cancer was diminished by genetically engineered hNSCs and noncytotoxic drug 5-FC. This is the first report of the therapeutic potential of i.v. injected hNSCs in a metastasis model; therefore, the results indicate that this stem cell therapy can be used as an alternative novel tool to treat metastatic choriocarcinoma.

Effects of bisphenol compounds on the growth and epithelial mesenchymal transition of MCF-7 CV human breast cancer cells

Bisphenol-A (BPA) has been considered as an endocrine disrupting chemical (EDC) because it can exert estrogenic properties. For bisphenol-S (BPS) and bisphenol-F (BPF) that are BPA analogs and substitutes, their risk to estrogen-dependent cancer has been reported rarely compared with the numerous cases of BPA. In this study, we examined whether BPA, BPS, and BPF can lead to the proliferation, migration, and epithelial mesenchymal transition (EMT) of MCF-7 clonal variant (MCF-7 CV) breast cancer cells expressing estrogen receptors (ERs). In a cell viability assay, BPA, BPS, and BPF significantly increased proliferation of MCF-7 CV cells compared to control (DMSO) as did 17β-estradiol (E2). In Western blotting assay, BPA, BPS, and BPF enhanced the protein expression of cell cycle progression genes such as cyclin D1 and E1. In addition, MCF-7 CV cells lost cell to cell contacts and acquired fibroblast-like morphology by the treatment of BPA, BPS, or BPF for 24 hours. In cell migration assay, BPA, BPS, and BPF accelerated the migration capability of MCF-7 CV cells as did E2. In relation with the EMT process, BPA, BPS, and BPF increased the protein expression ofN-cadherin, while they decreased the protein expression of E-cadherin. When BPA, BPS, and BPF were co-treated with ICI 182,780, an ER antagonist, proliferation effects were reversed, the expression of cyclin D1 and cyclin E1 was downregulated, and the altered cell migration and expression ofN-cadherin and E-cadherin by BPA, BPS, and BPF were restored to the control level. Thus, these results imply that BPS and BPF also have the risk of breast cancer progression as much as BPA in the induction of proliferation and migration of MCF-7 CV cells by regulating the protein expression of cell cycle-related genes and EMT markersvia the ER-dependent pathway.

Anti-angiogenesis for cancer revisited: Is there a role for combinations with immunotherapy?

Angiogenesis is defined as the formation of new blood vessels from preexisting vessels and has been characterized as an essential process for tumor cell proliferation and viability. This has led to the development of pharmacological agents for anti-angiogenesis to disrupt the vascular supply and starve tumor of nutrients and oxygen, primarily through blockade of VEGF/VEGFR signaling. This effort has resulted in 11 anti-VEGF drugs approved for certain advanced cancers, alone or in combination with chemotherapy or other targeted therapies. But this success had only limited impact on overall survival of cancer patients and rarely resulted in durable responses. Given the recent success of immunotherapies, combinations of anti-angiogenics with immune checkpoint blockers have become an attractive strategy. However, implementing such combinations will require a better mechanistic understanding of their interaction. Due to overexpression of pro-angiogenic factors in tumors, their vasculature is often tortuous and disorganized, with excessively branched leaky vessels. This enhances vascular permeability, which in turn is associated with high interstitial fluid pressure, and a reduction in blood perfusion and oxygenation. Judicious dosing of anti-angiogenic treatment can transiently normalize the tumor vasculature by decreasing vascular permeability and improving tumor perfusion and blood flow, and synergize with immunotherapy in this time window. However, anti-angiogenics may also excessively prune tumor vessels in a dose and time-dependent manner, which induces hypoxia and immunosuppression, including increased expression of the immune checkpoint programmed death receptor ligand (PD-L1). This review focuses on revisiting the concept of anti-angiogenesis in combination with immunotherapy as a strategy for cancer treatment.