CXCR4 expression in prostate cancer progenitor cells. PLoS One. 2012;7:e31226. [PMID: 22359577 PMCID: PMC3281066 DOI: 10.1371/journal.pone.0031226]

Cancer-associated fibroblasts and prostate cancer stem cells: crosstalk mechanisms and implications for disease progression

The functional heterogeneity and ecological niche of prostate cancer stem cells (PCSCs), which are major drivers of prostate cancer development and treatment resistance, have attracted considerable research attention. Cancer-associated fibroblasts (CAFs), which are crucial components of the tumor microenvironment (TME), substantially affect PCSC stemness. Additionally, CAFs promote PCSC growth and survival by releasing signaling molecules and modifying the surrounding environment. Conversely, PCSCs may affect the characteristics and behavior of CAFs by producing various molecules. This crosstalk mechanism is potentially crucial for prostate cancer progression and the development of treatment resistance. Using organoids to model the TME enables an in-depth study of CAF-PCSC interactions, providing a valuable preclinical tool to accurately evaluate potential target genes and design novel treatment strategies for prostate cancer. The objective of this review is to discuss the current research on the multilevel and multitarget regulatory mechanisms underlying CAF-PCSC interactions and crosstalk, aiming to inform therapeutic approaches that address challenges in prostate cancer treatment.

CXCR4 Expression as a Prognostic Biomarker in Soft Tissue Sarcomas

Poor long-term survival in localized high-risk soft tissue sarcomas (STSs) of the extremities and trunk highlights the need to identify new prognostic factors. CXCR4 is a chemokine receptor involved in tumor progression, angiogenesis, and metastasis. The aim of this study was to evaluate the association between CXCR4 expression in tumor tissue and survival in STSs patients treated with neoadjuvant therapy. CXCR4 expression was retrospectively determined by immunohistochemical analysis in serial specimens including initial biopsies, tumors post-neoadjuvant treatment, and tumors after relapse. We found that a positive cytoplasmatic expression of CXCR4 in tumors after neoadjuvant treatment was a predictor of poor recurrence-free survival (RFS) (p = 0.003) and overall survival (p = 0.019) in synovial sarcomas. We also found that positive nuclear CXCR4 expression in the initial biopsies was associated with poor RFS (p = 0.022) in undifferentiated pleomorphic sarcomas. In conclusion, our study adds to the evidence that CXCR4 expression in tumor tissue is a promising prognostic factor for STSs.

Genome-wide CRISPR/Cas9 screen reveals JunB downmodulation of HIV co-receptor CXCR4

HIV-1 relies extensively on host cell machinery for replication. Identification and characterization of these host-virus interactions is vital to our understanding of viral replication and the consequences of infection in cells. Several prior screens have identified host factors important for HIV replication but with limited replication of findings, likely due to differences in experimental design and conditions. Thus, unidentified factors likely exist. To identify novel host factors required for HIV-1 infection, we performed a genome-wide CRISPR/Cas9 screen using HIV-induced cell death as a partitioning method. We created a gene knockout library in TZM-GFP reporter cells using GeCKOv2, which targets 19,050 genes, and infected the library with a lethal dose of HIV-1NL4-3. We hypothesized that cells with a knockout of a gene critical for HIV infection would survive while cells with a knockout of a non-consequential gene would undergo HIV-induced death and be lost from the population. Surviving cells were analyzed by high throughput sequencing of the integrated CRISPR/Cas9 cassette to identify the gene knockout. Of the gene targets, an overwhelming majority of the surviving cells harbored the guide sequence for the AP-1 transcription factor family protein, JunB. Upon the generation of a clonal JunB knockout cell line, we found that HIV-1NL4-3 infection was blocked in the absence of JunB. The phenotype resulted from downregulation of CXCR4, as infection levels were recovered by reintroduction of CXCR4 in JunB KO cells. Thus, JunB downmodulates CXCR4 expression in TZM-GFP cells, reducing CXCR4-tropic HIV infection.

The role of proinflammatory cytokines and CXC chemokines (CXCL1-CXCL16) in the progression of prostate cancer: insights on their therapeutic management

Reproductive cancers are malignancies that develop in the reproductive organs. One of the leading cancers affecting the male reproductive system on a global scale is prostate cancer (PCa). The negative consequences of PCa metastases endure and are severe, significantly affecting mortality and life quality for those who are affected. The association between inflammation and PCa has captured interest for a while. Inflammatory cells, cytokines, CXC chemokines, signaling pathways, and other elements make up the tumor microenvironment (TME), which is characterized by inflammation. Inflammatory cytokines and CXC chemokines are especially crucial for PCa development and prognosis. Cytokines (interleukins) and CXC chemokines such as IL-1, IL-6, IL-7, IL-17, TGF-β, TNF-α, CXCL1-CXCL6, and CXCL8-CXCL16 are thought to be responsible for the pleiotropic effects of PCa, which include inflammation, progression, angiogenesis, leukocyte infiltration in advanced PCa, and therapeutic resistance. The inflammatory cytokine and CXC chemokines systems are also promising candidates for PCa suppression and immunotherapy. Therefore, the purpose of this work is to provide insight on how the spectra of inflammatory cytokines and CXC chemokines evolve as PCa develops and spreads. We also discussed recent developments in our awareness of the diverse molecular signaling pathways of these circulating cytokines and CXC chemokines, as well as their associated receptors, which may one day serve as PCa-targeted therapies. Moreover, the current status and potential of theranostic PCa therapies based on cytokines, CXC chemokines, and CXC receptors (CXCRs) are examined.

Informed by Cancer Stem Cells of Solid Tumors: Advances in Treatments Targeting Tumor-Promoting Factors and Pathways

Cancer stem cells (CSCs) represent a subpopulation within tumors that promote cancer progression, metastasis, and recurrence due to their self-renewal capacity and resistance to conventional therapies. CSC-specific markers and signaling pathways highly active in CSCs have emerged as a promising strategy for improving patient outcomes. This review provides a comprehensive overview of the therapeutic targets associated with CSCs of solid tumors across various cancer types, including key molecular markers aldehyde dehydrogenases, CD44, epithelial cellular adhesion molecule, and CD133 and signaling pathways such as Wnt/β-catenin, Notch, and Sonic Hedgehog. We discuss a wide array of therapeutic modalities ranging from targeted antibodies, small molecule inhibitors, and near-infrared photoimmunotherapy to advanced genetic approaches like RNA interference, CRISPR/Cas9 technology, aptamers, antisense oligonucleotides, chimeric antigen receptor (CAR) T cells, CAR natural killer cells, bispecific T cell engagers, immunotoxins, drug-antibody conjugates, therapeutic peptides, and dendritic cell vaccines. This review spans developments from preclinical investigations to ongoing clinical trials, highlighting the innovative targeting strategies that have been informed by CSC-associated pathways and molecules to overcome therapeutic resistance. We aim to provide insights into the potential of these therapies to revolutionize cancer treatment, underscoring the critical need for a multi-faceted approach in the battle against cancer. This comprehensive analysis demonstrates how advances made in the CSC field have informed significant developments in novel targeted therapeutic approaches, with the ultimate goal of achieving more effective and durable responses in cancer patients.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells (CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

A CXCR4 inhibitor (balixafortide) enhances docetaxel-mediated antitumor activity in a murine model of prostate cancer bone metastasis

BACKGROUND

Prostate cancer (PCa) bone metastases have been shown to be more resistant to docetaxel than soft tissue metastases. The proinflammatory chemokine receptor CXCR4 has been shown to confer resistance to docetaxel (DOC) in PCa cells. Balixafortide (BLX) is a protein epitope mimetic inhibitor of CXCR4. Accordingly, we hypothesized that BLX would enhance DOC-mediated antitumor activity in PCa bone metastases.

METHODS

PC-3 luciferase-labeled cells were injected into the tibia of mice to model bone metastases. Four treatment groups were created: vehicle, DOC (5 mg/kg), BLX (20 mg/kg), and combo (receiving both DOC and BLX). Mice were injected twice daily subcutaneously with either vehicle or BLX starting on Day 1 and weekly intraperitoneally with DOC starting on Day 1. Tumor burden was measured weekly via bioluminescent imaging. At end of study (29 days), radiographs were taken of the tibiae and blood was collected. Serum levels of TRAcP, IL-2, and IFNγ levels were measured using ELISA. Harvested tibiae were decalcified and stained for Ki67, cleaved caspase-3, and CD34 positive cells or microvessels were quantified.

RESULTS

Tumor burden was lower in the combo group compared to the DOC alone group. Treatment with the combination had no impact on the number of mice with osteolytic lesions, however the area of osteolytic lesions was lower in the combo group compared to the vehicle and BLX groups, but not the DOC group. Serum TRAcP levels were lower in the combo compared to vehicle group, but not the other groups. No significant difference in Ki67 staining was found among the groups; whereas, cleaved caspase-3 staining was lowest in the Combo group and highest in the BLX group. The DOC and combo groups had more CD34+ microvessels than the control and BLX groups. There was no difference between the treatment groups for IL-2, but the combo group had increased levels of IFNγ compared to the DOC group.

CONCLUSIONS

Our data demonstrate that a combination of BAL and DOC has greater antitumor activity in a model of PCa bone metastases than either drug alone. These data support further evaluation of this combination in metastatic PCa.

Cancer stem cell fate determination: mito-nuclear communication

Cancer stem cells (CSCs) are considered to be responsible for tumor recurrence and metastasis. Therefore, clarification of the mechanisms involved in CSC stemness maintenance and cell fate determination would provide a new strategy for cancer therapy. Unregulated cellular energetics has been accepted as one of the hallmarks of cancer cells, but recent studies have revealed that mitochondrial metabolism can also actively determine CSC fate by affecting nuclear stemness gene expression. Herein, from the perspective of mito-nuclear communication, we review recent progress on the influence of mitochondria on CSC potential from four aspects: metabolism, dynamics, mitochondrial homeostasis, and reactive oxygen species (ROS). Video Abstract.

Theranostics of Primary Prostate Cancer: Beyond PSMA and GRP-R

The imaging of Prostate-Specific Membrane Antigen (PSMA) is now widely used at the initial staging of prostate cancers in patients with a high metastatic risk. However, its ability to detect low-grade tumor lesions is not optimal.

METHODS

First, we prospectively performed neurotensin receptor-1 (NTS₁) IHC in a series of patients receiving both [⁶⁸Ga]Ga-PSMA-617 and [⁶⁸Ga]Ga-RM2 before prostatectomy. In this series, PSMA and GRP-R IHC were also available (n = 16). Next, we aimed at confirming the PSMA/GRP-R/NTS₁ expression profile by retrospective autoradiography (n = 46) using a specific radiopharmaceuticals study and also aimed to decipher the expression of less-investigated targets such as NTS₂, SST₂ and CXCR4.

RESULTS

In the IHC study, all samples with negative PSMA staining (two patients with ISUP 2 and one with ISUP 3) were strongly positive for NTS₁ staining. No samples were negative for all three stains-for PSMA, GRP-R or NTS₁. In the autoradiography study, binding of [¹¹¹In]In-PSMA-617 was high in all ISUP groups. However, some samples did not bind or bound weakly to [¹¹¹In]In-PSMA-617 (9%). In these cases, binding of [¹¹¹n]In-JMV 6659 and [¹¹¹In]In-JMV 7488 towards NTS₁ and NTS₂ was high.

CONCLUSIONS

Targeting PSMA and NTS₁/NTS₂ could allow for the detection of all intraprostatic lesions.

Dynamics of CXCR4 positive circulating tumor cells in prostate cancer patients during radiotherapy

Ablative radiotherapy is a highly efficient treatment modality for patients with metastatic prostate cancer (PCa). However, a subset of patients does not respond. Currently, this subgroup with bad prognosis cannot be identified before disease progression. We hypothesize that markers indicative of radioresistance, stemness and/or bone tropism may have a prognostic potential to identify patients profiting from metastases-directed radiotherapy. Therefore, circulating tumor cells (CTCs) were analyzed in patients with metastatic PCa (n = 24) during radiotherapy with CellSearch, multicolor flow cytometry and imaging cytometry. Analysis of copy-number alteration indicates a polyclonal CTC population that changes after radiotherapy. CTCs were found in 8 out of 24 patients (33.3%) and were associated with a shorter time to biochemical progression after radiotherapy. Whereas the total CTC count dropped after radiotherapy, a chemokine receptor CXCR4-expressing subpopulation representing 28.6% of the total CTC population remained stable up to 3 months. At once, we observed higher chemokine CCL2 plasma concentrations and proinflammatory monocytes. Additional functional analyses demonstrated key roles of CXCR4 and CCL2 for cellular radiosensitivity, tumorigenicity and stem-like potential in vitro and in vivo. Moreover, a high CXCR4 and CCL2 expression was found in bone metastasis biopsies of PCa patients. In summary, panCK⁺ CXCR4⁺ CTCs may have a prognostic potential in patients with metastatic PCa treated with metastasis-directed radiotherapy.

Distinct Expression of Surface and Genetic Biomarkers in Prostate Cancer Cell Lines

BACKGROUND/AIM

Surface biomarkers, such as CD44 and CD133, have been demonstrated to be expressed in prostate cancer cells, and our previous study has shown that prostate cancer cell lines could be divided into three groups according to the single and combined expression pattern of CD44 and 133. In order to refine prognostication in prostate cancer cells, we further investigated genetic biomarkers, prostate cancer antigen 3 (PCA3), kallikrein 4 (KLK4), and KLK9 in different prostate cancer cell lines.

MATERIALS AND METHODS

CWR22Rv1, PC3, and DU145 cell lines were cultured until 95% confluence. The single expression of CD44 or CD133 and their combined expression were analyzed by flow cytometry, and gene expression of b-actin, PCA3, KLK4, and KLK9 was analyzed by real-time polymerase chain reaction.

RESULTS

The single expression of CD133 was less than 4% in all cell lines examined. PC3 and DU145 cells displayed a high expression of CD44 (>91%), whereas CWR22Rv1 was the only cell line that demonstrated a high co-expression of both CD44 and CD133 (>91%). In addition, PC3 and DU145 displayed low expression of PCA3, KLK4, and KLK9 when compared with their own b-actin expression. In contrast, CWR22Rva showed high expression of PCA3 and KLK4 although KLK9 expression was also low.

CONCLUSION

Both surface and genetic biomarkers should be validated for a more accurate prognosis in prostate cancer.

Cancer Stemness/Epithelial-Mesenchymal Transition Axis Influences Metastasis and Castration Resistance in Prostate Cancer: Potential Therapeutic Target

Prostate cancer (PCa) is a leading cause of cancer death in men, worldwide. Mortality is highly related to metastasis and hormone resistance, but the molecular underlying mechanisms are poorly understood. We have studied the presence and role of cancer stem cells (CSCs) and the Epithelial-Mesenchymal transition (EMT) in PCa, using both in vitro and in vivo models, thereby providing evidence that the stemness-mesenchymal axis seems to be a critical process related to relapse, metastasis and resistance. These are complex and related processes that involve a cooperative action of different cancer cell subpopulations, in which CSCs and mesenchymal cancer cells (MCCs) would be responsible for invading, colonizing pre-metastatic niches, initiating metastasis and an evading treatments response. Manipulating the stemness-EMT axis genes on the androgen receptor (AR) may shed some light on the effect of this axis on metastasis and castration resistance in PCa. It is suggested that the EMT gene SNAI2/Slug up regulates the stemness gene Sox2, and vice versa, inducing AR expression, promoting metastasis and castration resistance. This approach will provide new sight about the role of the stemness-mesenchymal axis in the metastasis and resistance mechanisms in PCa and their potential control, contributing to develop new therapeutic strategies for patients with metastatic and castration-resistant PCa.

Chemokines and cytokines: Axis and allies in prostate cancer pathogenesis

Chemokines are recognized as the major contributor to various tumorigenesis, tumor heterogeneity, and failures of current cancer therapies. The tumor microenvironment (TME) is enriched with chemokines and cytokines and plays a pivotal role in cancer progression. Chronic inflammation is also considered an instructive process of cancer progression, where chemokines are spatiotemporally secreted by malignant cells and leukocyte subtypes that initiate cell trafficking into the TME. In various cancers, prostate cancer (PCa) is reported as one of the leading cancers in the worldwide male population. The chemokines-mediated signaling pathways are intensively involved in PCa progression and metastasis. Emerging evidence suggests that chemokines and cytokines are responsible for the pleiotropic actions in cancer, including the growth, angiogenesis, endothelial mesenchymal transition, leukocyte infiltration, and hormone escape for advanced PCa and therapy resistance. Chemokine's system and immune cells represent a promising target to suppress tumorigenic environments and serve as potential therapy/immunotherapy for the PCa. In this review, an attempt has been made to shed light on the alteration of chemokine and cytokine profiles during PCa progression and metastasis. We also discussed the recent findings of the diverse molecular signaling of these circulating chemokines and their corresponding receptors that could become future targets for therapeutic management of PCa.

Multifaceted role of chemokines in solid tumors: From biology to therapy

Chemokines are small secretory chemotactic cytokines that control the directed migration of immune cells. Chemokines are involved in both anti-and pro-tumorigenic immune responses. Accumulating evidence suggests that the balance between these responses is influenced by several factors such as the stage of tumorigenesis, immune cell activation, recruitment of immune activating or immunosuppressive cells in the tumor microenvironment (TME), and chemokine receptor expression on effector and regulatory target cells. Cancer cells engage in a complex network with their TME components via several factors including growth factors, cytokines and chemokines that are critical for the growth of primary tumor and metastasis. However, chemokines show a multifaceted role in tumor progression including maintenance of stem-like properties, tumor cell proliferation/survival/senescence, angiogenesis, and metastasis. The heterogeneity of solid tumors in primary and metastatic cancers presents a challenge to the development of successful cancer therapy. Despite extensive research on how solid tumors escape immune cell-mediated anti-tumor response, finding an effective therapy for metastatic cancer still remains a challenge. This review discusses the multifarious roles of chemokines in solid tumors including various chemokine signaling pathways such as CXCL8-CXCR1/2, CXCL9, 10, 11-CXCR3, CXCR4-CXCL12, CCL(X)-CCR(X) in primary and metastatic cancers. We further discuss the novel therapeutic approaches that have been developed by major breakthroughs in chemokine research to treat cancer patients by the strategic blockade/activation of these signaling axes alone or in combination with immunotherapies.

Chemokines network in bone metastasis: Vital regulators of seeding and soiling

Chemokines are well equipped with chemo-attractive signals that can regulate cancer cell trafficking to specific organ sites. Currently, updated concepts have revealed the diverse role of chemokines in the biology of cancer initiation and progression. Genomic instabilities and alterations drive tumor heterogeneity, providing more options for the selection and metastatic progression to cancer cells. Tumor heterogeneity and acquired drug resistance are the main obstacles in managing cancer therapy and the primary root cause of metastasis. Studies emphasize that multiple chemokine/receptor axis are involved in cancer cell-mediated organ-specific distant metastasis. One of the persuasive mechanisms for heterogeneity and subsequent events is sturdily interlinked with the crosstalk between chemokines and their receptors on cancer cells and tissue-specific microenvironment. Among different metastatic niches, skeletal metastasis is frequently observed in the late stages of prostate, breast, and lung cancer and significantly reduces the survival of cancer patients. Therefore, it is crucial to elucidate the role of chemokines and their receptors in metastasis and bone remodeling. Here, we review the potential chemokine/receptor axis in tumorigenesis, tumor heterogeneity, metastasis, and vicious cycle in bone microenvironment.

Prostate Cancer Stem Cells: Clinical Aspects and Targeted Therapies

Despite decades of research and successful improvements in diagnosis and therapy, prostate cancer (PC) remains a major challenge. In recent years, it has become clear that PC stem cells (PCSCs) are the driving force in tumorigenesis, relapse, metastasis, and therapeutic resistance of PC. In this minireview, we discuss the impact of PCSCs in the clinical practice. Moreover, new therapeutic approaches to combat PCSCs are presented with the aim to achieve an improved outcome for patients with PC.

Access and Representation: A Narrative Review of the Disparities in Access to Clinical Trials and Precision Oncology in Black men with Prostate Cancer

OBJECTIVE

To provide commentary on the disparities in access to clinical trials and precision oncology specific to Black men with Prostate Cancer (PCa) in the United States and lend a general framework to aid in closing these gaps.

MATERIALS AND METHODS

The ideas, commentaries and data presented in this narrative review were synthesized by utilizing qualitative and quantitative studies, reviews, and randomized control trials performed between 2010 and 2021. We searched PubMed using the key words "Medicaid", "Medicare", "clinical trials", "African Americans", "Black", "underrepresentation", "access", "Prostate Cancer", "minority recruitment", "racial disparities", "disparity", "genomics", "biomarkers", "diagnostic" "prognostic", "validation", "precision medicine", and "precision oncology" to identify important themes, trends and data described in the current review. Keywords were used alone and combination with both "AND" and "OR" terms.

RESULTS

Black men with prostate cancer (PCa) in the United States have earlier onset of disease, present with more advanced stages, and worse prostate cancer-specific survival than their White counterparts. Potential causative factors vary from disparities in health care access to differences in tumor immunobiology and genomics along with disparate screening rates, management patterns and underrepresentation in clinical and translational research such as clinical trials and precision oncology.

CONCLUSION

To avoid increasing the racial disparity in PCa outcomes for Black men, we must increase inclusion of Black men into precision oncology and clinical trials, using multilevel change. Underrepresentation in clinical and translational research may potentiate poorly validated risk calculators and biomarkers, leading to poor treatment decisions in high-risk populations. Relevant actions include funding to include minority-serving institutions as recruitment sites, and inclusion of evidence based recruitment methods in funded research to increase Black representation in clinical trials and translational research.

pH-sensitive nanoliposomes for passive and CXCR-4-mediated marine yessotoxin delivery for cancer therapy

Background: Yessotoxin (YTX), a marine-derived drug, was encapsulated in PEGylated pH-sensitive nanoliposomes, covalently functionalized (strategy I) with SDF-1α and by nonspecific adsorption (strategy II), to actively target chemokine receptor CXCR-4. Methods: Cytotoxicity to normal human epithelial cells (HK-2) and prostate (PC-3) and breast (MCF-7) adenocarcinoma models, with different expression levels of CXCR-4, were tested. Results: Strategy II exerted the highest cytotoxicity toward cancer cells while protecting normal epithelia. Acid pH-induced fusion of nanoliposomes seemed to serve as a primary route of entry into MCF-7 cells but PC-3 data support an endocytic pathway for their internalization. Conclusion: This work describes an innovative hallmark in the current marine drug clinical pipeline, as the developed nanoliposomes are promising candidates in the design of groundbreaking marine flora-derived anticancer nanoagents.

Screening of Immune-Related Genes and Predicting the Immunotherapeutic Effects of Formononetin in Breast Cancer: A Bioinformatics Analysis

Objective

Immunotherapy is a promising breast cancer treatment. Nonetheless, tumor heterogeneity and the interaction between immune cells in the tumor microenvironment limit its effectiveness. Formononetin—extracted from the Chinese medicinal plant Astragalus membranaceus—can inhibit tumor growth, induce apoptosis and angiogenesis, and reverse multidrug resistance. However, its efficacy and mechanism of action on the immune cells in breast cancer remain unclear. Here, we screened immune-related genes of breast cancer to determine the potential of formononetin as a therapeutic.

Methods

GSE103512 and GSE139038 breast cancer microarray data and immune-related gene data were obtained from the GEO and ImmPort databases, respectively, to analyze the differentially expressed immune-related genes (IRGs) in breast cancer tissues compared with normal breast tissues. Protein-protein interaction (PPI) analysis was performed using the STRING database to screen differentially expressed IRGs based on the topological parameters. The Kaplan–Meier test was applied to detect differentially expressed IRGs associated with breast cancer survival, and the interaction of formononetin with differentially expressed IRGs was analyzed using molecular docking. Finally, the relationship between differentially expressed IRGs and breast cancer immune cell infiltration was analyzed using the TIMER2.0 database.

Results

A total of 29 differentially expressed IRGs of breast cancer were screened through GEO and ImmPort databases and 10 key differentially expressed IRGs based on the topological parameters from the PPI network. Among these, CXCL12, ESR1, IGF1, and FOS were associated with breast cancer survival. Furthermore, IGF1, ESR1, and CXCL12 were found to have stable binding sites for formononetin. These genes were associated with substantial immune cell infiltration in breast cancer tissues.

Conclusion

In conclusion, formononetin may exert antitumor effects by acting on CXCL12, ESR1, and IGF1 and may have a potential synergistic effect with immune checkpoint inhibitors.

Thromboinflammatory Processes at the Nexus of Metabolic Dysfunction and Prostate Cancer: The Emerging Role of Periprostatic Adipose Tissue

Simple Summary

As overweight and obesity increase among the population worldwide, a parallel increase in the number of individuals diagnosed with prostate cancer was observed. There appears to be a relationship between both diseases where the increase in the mass of fat tissue can lead to inflammation. Such a state of inflammation could produce many factors that increase the aggressiveness of prostate cancer, especially if this inflammation occurred in the fat stores adjacent to the prostate. Another important observation that links obesity, fat tissue inflammation, and prostate cancer is the increased production of blood clotting factors. In this article, we attempt to explain the role of these latter factors in the effect of increased body weight on the progression of prostate cancer and propose new ways of treatment that act by affecting how these clotting factors work.

Abstract

The increased global prevalence of metabolic disorders including obesity, insulin resistance, metabolic syndrome and diabetes is mirrored by an increased incidence of prostate cancer (PCa). Ample evidence suggests that these metabolic disorders, being characterized by adipose tissue (AT) expansion and inflammation, not only present as risk factors for the development of PCa, but also drive its increased aggressiveness, enhanced progression, and metastasis. Despite the emerging molecular mechanisms linking AT dysfunction to the various hallmarks of PCa, thromboinflammatory processes implicated in the crosstalk between these diseases have not been thoroughly investigated. This is of particular importance as both diseases present states of hypercoagulability. Accumulating evidence implicates tissue factor, thrombin, and active factor X as well as other players of the coagulation cascade in the pathophysiological processes driving cancer development and progression. In this regard, it becomes pivotal to elucidate the thromboinflammatory processes occurring in the periprostatic adipose tissue (PPAT), a fundamental microenvironmental niche of the prostate. Here, we highlight key findings linking thromboinflammation and the pleiotropic effects of coagulation factors and their inhibitors in metabolic diseases, PCa, and their crosstalk. We also propose several novel therapeutic targets and therapeutic interventions possibly modulating the interaction between these pathological states.

Cancer Stem Cell Markers for Urinary Carcinoma

Cancer stem cell (CSC) refers to cancer cells with stem cell properties, that is, they have the ability of “self-renewal” and “differentiation.” Cancer stem cells exist in cancer cells and are the “culprit” of cancer recurrence and metastasis. It is difficult to be found because of its small amount, and it is difficult for anticancer drugs to produce effects on it. At present, the isolation and identification of cancer stem cells from many solid tumors are still quite difficult, mainly due to the lack of specific molecular markers of cancer stem cells. In this review, cancer stem cell surface markers and functional markers in urinary system were summarized. These markers can provide molecular targets for cancer therapy.

Cellular plasticity upon proton irradiation determines tumor cell radiosensitivity

Proton radiotherapy has been implemented into the standard-of-care for cancer patients within recent years. However, experimental studies investigating cellular and molecular mechanisms are lacking, and prognostic biomarkers are needed. Cancer stem cell (CSC)-related biomarkers, such as aldehyde dehydrogenase (ALDH), are known to influence cellular radiosensitivity through inactivation of reactive oxygen species, DNA damage repair, and cell death. In a previous study, we found that ionizing radiation itself enriches for ALDH-positive CSCs. In this study, we analyze CSC marker dynamics in prostate cancer, head and neck cancer, and glioblastoma cells upon proton beam irradiation. We find that proton irradiation has a higher potential to target CSCs through induction of complex DNA damages, lower rates of cellular senescence, and minor alteration in histone methylation pattern compared with conventional photon irradiation. Mathematical modeling indicates differences in plasticity rates among ALDH-positive CSCs and ALDH-negative cancer cells between the two irradiation types.

Controlling Cell Trafficking: Addressing Failures in CAR T and NK Cell Therapy of Solid Tumours

The precision guiding of endogenous or adoptively transferred lymphocytes to the solid tumour mass is obligatory for optimal anti-tumour effects and will improve patient safety. The recognition and elimination of the tumour is best achieved when anti-tumour lymphocytes are proximal to the malignant cells. For example, the regional secretion of soluble factors, cytotoxic granules, and cell-surface molecule interactions are required for the death of tumour cells and the suppression of neovasculature formation, tumour-associated suppressor, or stromal cells. The resistance of individual tumour cell clones to cellular therapy and the hostile environment of the solid tumours is a major challenge to adoptive cell therapy. We review the strategies that could be useful to overcoming insufficient immune cell migration to the tumour cell mass. We argue that existing 'competitive' approaches should now be revisited as complementary approaches to improve CAR T and NK cell therapy.

Cancer stem cells: advances in biology and clinical translation-a Keystone Symposia report

The test for the cancer stem cell (CSC) hypothesis is to find a target expressed on all, and only CSCs in a patient tumor, then eliminate all cells with that target that eliminates the cancer. That test has not yet been achieved, but CSC diagnostics and targets found on CSCs and some other cells have resulted in a few clinically relevant therapies. However, it has become apparent that eliminating the subset of tumor cells characterized by self-renewal properties is essential for long-term tumor control. CSCs are able to regenerate and initiate tumor growth, recapitulating the heterogeneity present in the tumor before treatment. As great progress has been made in identifying and elucidating the biology of CSCs as well as their interactions with the tumor microenvironment, the time seems ripe for novel therapeutic strategies that target CSCs to find clinical applicability. On May 19-21, 2021, researchers in cancer stem cells met virtually for the Keystone eSymposium "Cancer Stem Cells: Advances in Biology and Clinical Translation" to discuss recent advances in the understanding of CSCs as well as clinical efforts to target these populations.

Bidirectional Interaction Between Cancer Cells and Platelets Provides Potential Strategies for Cancer Therapies

Platelets are essential components in the tumor microenvironment. For decades, clinical data have demonstrated that cancer patients have a high risk of thrombosis that is associated with adverse prognosis and decreased survival, indicating the involvement of platelets in cancer progression. Increasing evidence confirms that cancer cells are able to induce production and activation of platelets. Once activated, platelets serve as allies of cancer cells in tumor growth and metastasis. They can protect circulating tumor cells (CTCs) against the immune system and detachment-induced apoptosis while facilitating angiogenesis and tumor cell adhesion and invasion. Therefore, antiplatelet agents and platelet-based therapies should be developed for cancer treatment. Here, we discuss the mechanisms underlying the bidirectional cancer-platelet crosstalk and platelet-based therapeutic approaches.

Racial disparity in prostate cancer in the African American population with actionable ideas and novel immunotherapies

BACKGROUND

African Americans (AAs) in the United States are known to have a higher incidence and mortality for Prostate Cancer (PCa). The drivers of this epidemiological disparity are multifactorial, including socioeconomic factors leading to lifestyle and dietary issues, healthcare access problems, and potentially tumor biology.

RECENT FINDINGS

Although recent evidence suggests once access is equal, AA men have equal outcomes to Caucasian American (CA) men, differences in PCa incidence remain, and there is much to do to reverse disparities in mortality across the USA. A deeper understanding of these issues, both at the clinical and molecular level, can facilitate improved outcomes in the AA population. This review first discusses PCa oncogenesis in the context of its diverse hallmarks before benchmarking key molecular and genomic differences for PCa in AA men that have emerged in the recent literature. Studies have emphasized the importance of tumor microenvironment that contributes to both the unequal cancer burden and differences in clinical outcome between the races. Management of comorbidities like obesity, hypertension, and diabetes will provide an essential means of reducing prostate cancer incidence in AA men. Although requiring further AA specific research, several new treatment strategies such as immune checkpoint inhibitors used in combination PARP inhibitors and other emerging vaccines, including Sipuleucel-T, have demonstrated some proven efficacy.

CONCLUSION

Genomic profiling to integrate clinical and genomic data for diagnosis, prognosis, and treatment will allow physicians to plan a "Precision Medicine" approach to AA men. There is a pressing need for further research for risk stratification, which may allow early identification of AA men with higher risk disease based on their unique clinical, genomic, and immunological profiles, which can then be mapped to appropriate clinical trials. Treatment options are outlined, with a concise description of recent work in AA specific populations, detailing several targeted therapies, including immunotherapy. Also, a summary of current clinical trials involving AA men is presented, and it is important that policies are adopted to ensure that AA men are actively recruited. Although it is encouraging that many of these explore the lifestyle and educational initiatives and therapeutic interventions, there is much still work to be done to reduce incidence and mortality in AA men and equalize current racial disparities.

Insights into homeobox B9: a propeller for metastasis in dormant prostate cancer progenitor cells

BACKGROUND

Metastasis is the major cause of treatment failure and cancer-related deaths in prostate cancer (PCa) patients. Our previous study demonstrated that a CD44⁺ subpopulation isolated from PCa cells or tumours possesses both stem cell properties and metastatic potential, serving as metastatic prostate cancer stem cells (mPCSCs) in PCa metastasis. However, the underlying mechanisms remain unknown.

METHODS

In this study, we established PCa models via the orthotopic and subcutaneous implantation of different human PCa cancer cell lines, and compared the metastatic efficacy, after which process function analysis of target genes was pinpointed.

RESULTS

Several novel differentially expressed genes (DEGs) between orthotopic and ectopic tumours were identified. Among them, human homeobox B9 (HOXB9) transcription factor was found to be essential for PCa metastasis, as evidenced by the diminished number of lung metastatic foci derived from orthotopic implantation with HOXB9-deficient CWR22 cells, compared with the control. In addition, HOXB9 protein expression was upregulated in PCa tissues, compared with paracancer and benign prostate hyperplasia tissues. It was also positively correlated with Gleason scores. Gain- and loss-of-function assays showed that HOXB9 altered the expression of various tumour metastasis- and cancer stem cell (CSC) growth-related genes in a transforming growth factor beta (TGFβ)-dependent manner. Moreover, HOXB9 was overexpressed in an ALDH⁺CD44⁺CXCR4⁺CD24⁺ subpopulation of PCa cells that exhibited enhanced TGFβ-dependent tumorigenic and metastatic abilities, compared with other isogenic PCa cells. This suggests that HOXB9 may contribute to PCa tumorigenesis and metastasis via TGFβ signalling. Of note, ALDH⁺CD44⁺CXCR4⁺CD24⁺-PCa cells exhibited resistance to castration and antiandrogen therapy and were present in human PCa tissues.

CONCLUSION

Taken together, our study identified HOXB9 as a critical regulator of metastatic mPCSC behaviour. This occurs through altering the expression of a panel of CSC growth- and invasion/metastasis-related genes via TGFβ signalling. Thus, targeting HOXB9 is a potential novel therapeutic PCa treatment strategy.

Preferential interaction of platelets with prostate cancer cells with stem cell markers

BACKGROUND

Prostate cancer (PCa) may be initiated by CD133+/CD44+ expressing stem cell-like cells (PCSC), which are also thought to drive metastasis. Platelets also contribute to metastasis via tumor cell-induced platelet aggregation (TCIPA), which in part enhances cancer cell invasion. Moreover, activated platelets secrete stromal derived growth factor-1α (SDF-1α) that can mobilize CSCs via the CXCR4 receptor. However, the potential reciprocal interactions between CSCs and platelets have not been investigated.

OBJECTIVE

To characterize the mechanisms behind PCSC-platelet interaction.

METHODS

Fluorescence Activated Cell Sorting was utilized to separate DU145 and PC3 PCa cells into CD133+/CD44+, CD133+/CD44-, CD44+/CD133-, and CD133-/CD44- subpopulations and to measure their CXCR4 surface expression. PCa subpopulation TCIPA experiments were performed using aggregometry and immunoblot was used to measure prothrombin. Platelet SDF-1α secretion was measured by ELISA. Modified-Boyden chamber assays were used to assess the role of SDF-1α:CXCR4 pathway in platelet-PCSC interactions.

RESULTS

DU145 and PC3 expressing both CD133 and CD44 stem cell markers accounted for only small fractions of total cells (DU145: CD133+/CD44+ 3.44 ± 1.45% vs. CD133+/CD44- 1.56 ± 0.45% vs. CD44+/CD133- 68.19 ± 6.25% vs. CD133-/CD44- 20.36 ± 4.51%). However, CD133+ subpopulations induced the greatest amount of aggregation compared to CD44+/CD133- and double-negative DU145, and this aggregation potency of CD133+ PCa cells corresponded with high levels of prothrombin expression. Additionally, CD133+ subpopulations expressed significantly higher level of CXCR4 compared to CD133-/CD44- and CD44+/CD133-. Disruption of SDF-1α:CXCR4 pathway reduced platelet-induced PCSC invasion.

CONCLUSIONS

CD133+/CD44+ and CD133+/CD44- PCSCs have highest platelet aggregation potency, which could be attributed to their increased prothrombin expression. Reciprocally, platelet-derived SDF-1α stimulates PCSC invasion.

Analyzing the Expression of Biomarkers in Prostate Cancer Cell Lines

BACKGROUND/AIM

CD44 and CD133 have been implicated as biomarkers of cancer cells and their expression could be analyzed to identify circulating tumor cells. Although CD44 and CD133 have been shown to be expressed in prostate cancer cells, a differential expression pattern has been reported depending on the tumor stage and cell line examined. We further investigated CD44 and CD133 expression in different prostate cancer cell lines to confirm whether their expression is distinguishable among patients with various tumor stages.

MATERIALS AND METHODS

CWR22Rv1, PC3, LNCaP, and DU145 cell lines were cultured and the cell morphology was observed for three days. The single expression of CD44 or CD133 and their combined expression were analyzed by flow cytometry.

RESULTS

We report that the single expression of CD133 was less than 5% in all cell lines examined here. PC3 and DU145 cells displayed a high expression of CD44 (>93%), while the expression of CD44 was less than 4% in CWR22Rv1 and LNCaP cells. CWR22Rv1 was the only cell line that demonstrated a high co-expression of both CD44 and CD133.

CONCLUSION

Both single and combined expression of CD44 and CD133 should be considered when validating the detection of prostate cancer cells in circulating tumor cells.

Latest update on chemokine receptors as therapeutic targets

The chemokine system plays a fundamental role in a diverse range of physiological processes, such as homeostasis and immune responses. Dysregulation in the chemokine system has been linked to inflammatory diseases and cancer, which renders chemokine receptors to be considered as therapeutic targets. In the past two decades, around 45 drugs targeting chemokine receptors have been developed, yet only three are clinically approved. The challenging factors include the limited understanding of aberrant chemokine signalling in malignant diseases, high redundancy of the chemokine system, differences between cell types and non-specific binding of the chemokine receptor antagonists due to the broad ligand-binding pockets. In recent years, emerging studies attempt to characterise the chemokine ligand–receptor interactions and the downstream signalling protein–protein interactions, aiming to fine tuning to the promiscuous interplay of the chemokine system for the development of precision medicine. This review will outline the updates on the mechanistic insights in the chemokine system and propose some potential strategies in the future development of targeted therapy.

Chemokines orchestrate tumor cells and the microenvironment to achieve metastatic heterogeneity

Chemokines, a subfamily of the cell cytokines, are low molecular weight proteins known to induce chemotaxis in leukocytes in response to inflammatory and pathogenic signals. A plethora of literature demonstrates that chemokines and their receptors regulate tumor progression and metastasis. With these diverse functionalities, chemokines act as a fundamental link between the tumor cells and their microenvironment. Recent studies demonstrate that the biology of chemokines and their receptor in metastasis is complex as numerous chemokines are involved in regulating site-specific tumor growth and metastasis. Successful treatment of disseminated cancer is a significant challenge. The most crucial problem for treating metastatic cancer is developing therapy regimes capable of overcoming heterogeneity problems within primary tumors and among metastases and within metastases (intralesional). This heterogeneity of malignant tumor cells can be related to metastatic potential, response to chemotherapy or specific immunotherapy, and many other factors. In this review, we have emphasized the role of chemokines in the process of metastasis and metastatic heterogeneity. Individual chemokines may not express the full potential to address metastatic heterogeneity, but chemokine networks need exploration. Understanding the interplay between chemokine-chemokine receptor networks between the tumor cells and their microenvironment is a novel approach to overcome the problem of metastatic heterogeneity. Recent advances in the understanding of chemokine networks pave the way for developing a potential targeted therapeutic strategy to treat metastatic cancer.

The Effects of Resveratrol on Prostate Cancer through Targeting the Tumor Microenvironment

Prostate cancer is one of the most common cancers diagnosed in men in the United States and the second leading cause of cancer-related deaths worldwide. Since over 60% of prostate cancer cases occur in men over 65 years of age, and this population will increase steadily in the coming years, prostate cancer will be a major cancer-related burden in the foreseeable future. Accumulating data from more recent research suggest that the tumor microenvironment (TME) plays a previously unrecognized role in every stage of cancer development, including initiation, proliferation, and metastasis. Prostate cancer is not only diagnosed in the late stages of life, but also progresses relatively slowly. This makes prostate cancer an ideal model system for exploring the potential of natural products as cancer prevention and/or treatment reagents because they usually act relatively slowly compared to most synthetic drugs. Resveratrol (RSV) is a naturally occurring stilbenoid and possesses strong anti-cancer properties with few adverse effects. Accumulating data from both in vitro and in vivo experiments indicate that RSV can interfere with prostate cancer initiation and progression by targeting the TME. Therefore, this review is aimed to summarize the recent advancement in RSV-inhibited prostate cancer initiation, proliferation, and metastasis as well as the underlying molecular mechanisms, with particular emphasis on the effect of RSV on TME. This will not only better our understanding of prostate cancer TMEs, but also pave the way for the development of RSV as a potential reagent for prostate cancer prevention and/or therapy.

CXC Chemokine/Receptor Axis Profile and Metastasis in Prostate Cancer

In this study, the effects of the CXC chemokine/receptor axis on lymph node and distant metastases of prostate cancer (PC) were analyzed. Further, mRNA expression data of metastatic PC were extracted from the Stand Up To Cancer–Prostate Cancer Foundation Dream Team database and differences between metastatic sites were comprehensively analyzed. CXC chemokine/receptor mRNA expression data of primary PC included in the Cancer Genome Atlas were used to analyze the relationships of CXC chemokine/receptor expression with lymph node metastasis and cancer progression. In metastatic PC, significantly higher expression of ELR⁺ CXC chemokines/receptors and significantly lower expression of ELR⁻ CXC chemokines/receptors were observed in bone metastases relative to lymph node metastases. In primary PC, significantly higher ELR⁻ CXC chemokine/receptor expression and significantly lower ELR⁺ CXC chemokine/receptor expression were observed in patients with lymph node metastasis relative to those without. Multivariate logistic regression analysis identified CXCL10 expression as an independent predictor of lymph node metastasis. Furthermore, the log-rank test results revealed that co-expression of CXCL10/CXCR3 was associated with postoperative recurrence. These findings demonstrate heterogeneous expression of CXC chemokine/receptor genes in primary PC as well as differences in expression patterns according to the metastatic site.

The Chemokine Receptor CXCR4 in Cell Proliferation and Tissue Regeneration

The CXCR4 receptor upon binding its ligands triggers multiple signaling pathways that orchestrate cell migration, hematopoiesis and cell homing, and retention in the bone marrow. However, CXCR4 also directly controls cell proliferation of non-hematopoietic cells. This review focuses on recent reports pointing to its pivotal role in tissue regeneration and stem cell activation, and discusses the connection to the known role of CXCR4 in promoting tumor growth. The mechanisms may be similar in all cases, since regeneration often recapitulates developmental processes, and cancer often exploits developmental pathways. Moreover, cell migration and cell proliferation appear to be downstream of the same signaling pathways. A deeper understanding of the complex signaling originating from CXCR4 is needed to exploit the opportunities to repair damaged organs safely and effectively.

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.

Chemokines and their Receptors: Multifaceted Roles in Cancer Progression and Potential Value as Cancer Prognostic Markers

Chemokines are chemotactic cytokines that mediate immune cell chemotaxis and lymphoid tissue development. Recent advances have indicated that chemokines and their cognate receptors play critical roles in cancer-related inflammation and cancer progression. On the basis of these findings, the chemokine system has become a new potential drug target for cancer immunotherapy. In this review, we summarize the essential roles of the complex network of chemokines and their receptors in cancer progression. Furthermore, we discuss the potential value of the chemokine system as a cancer prognostic marker. The chemokine system regulates the infiltration of immune cells into the tumor microenvironment, which induces both pro- and anti-immunity and promotes or suppresses tumor growth and proliferation, angiogenesis, and metastasis. Increasing evidence indicates the promising prognostic value of the chemokine system in cancer patients. While CCL2, CXCL10, and CX3CL1/CX3CR1 can serve as favorable or unfavorable prognostic factors depending on the cancer types, CCL14 and XCL1 possess good prognostic value. Other chemokines such as CXCL1, CXCL8, and CXCL12 are poor prognostic markers. Despite vast advances in our understanding of the complex nature of the chemokine system in tumor biology, knowledge about the multifaceted roles of the chemokine system in different types of cancers is still limited. Further studies are necessary to decipher distinct roles within the chemokine system in terms of cancer progression and to validate their potential value in cancer prognosis.

FOXO1 regulates developmental lymphangiogenesis by upregulating CXCR4 in the mouse-tail dermis

Lymphangiogenesis plays important roles in normal fetal development and postnatal growth. However, its molecular regulation remains unclear. Here, we have examined the function of forkhead box protein O1 (FOXO1) transcription factor, a known angiogenic factor, in developmental dermal lymphangiogenesis using endothelial cell-specific FOXO1-deficient mice. FOXO1-deficient mice showed disconnected and dilated lymphatic vessels accompanied with increased proliferation and decreased apoptosis in the lymphatic capillaries. Comprehensive DNA microarray analysis of the causes of in vivo phenotypes in FOXO1-deficient mice revealed that the gene encoding C-X-C chemokine receptor 4 (CXCR4) was the most drastically downregulated in FOXO1-deficient primary lymphatic endothelial cells (LECs). CXCR4 was expressed in developing dermal lymphatic capillaries in wild-type mice but not in FOXO1-deficient dermal lymphatic capillaries. Furthermore, FOXO1 suppression impaired migration toward the exogenous CXCR4 ligand, C-X-C chemokine ligand 12 (CXCL12), and coordinated proliferation in LECs. These results suggest that FOXO1 serves an essential role in normal developmental lymphangiogenesis by promoting LEC migration toward CXCL12 and by regulating their proliferative activity. This study provides valuable insights into the molecular mechanisms underlying developmental lymphangiogenesis.

Psychosocial Stress, Glucocorticoid Signaling, and Prostate Cancer Health Disparities in African American Men

Recent advances in our understanding of racial disparities in prostate cancer (PCa) incidence and mortality that disproportionately affect African American (AA) men have provided important insights into the psychosocial, socioeconomic, environmental, and molecular contributors. There is, however, limited mechanistic knowledge of how the interplay between these determinants influences prostate tumor aggressiveness in AA men and other men of African ancestry. Growing evidence indicates that chronic psychosocial stress in AA populations leads to sustained glucocorticoid signaling through the glucocorticoid receptor (GR), with negative physiological and pathological consequences. Compelling evidence indicates that treatment of castration-resistant prostate cancer (CRPC) with anti-androgen therapy activates GR signaling. This enhanced GR signaling bypasses androgen receptor (AR) signaling and transcriptionally activates both AR-target genes and GR-target genes, resulting in increased prostate tumor resistance to anti-androgen therapy, chemotherapy, and radiotherapy. Given its enhanced signaling in AA men, GR-together with specific genetic drivers-may promote CRPC progression and exacerbate tumor aggressiveness in this population, potentially contributing to PCa mortality disparities. Ongoing and future CRPC clinical trials that combine standard of care therapies with GR modulators should assess racial differences in therapy response and clinical outcomes in order to improve PCa health disparities that continue to exist for AA men.

Molecular Mechanisms Underlying the Functions of Cellular Markers Associated with the Phenotype of Cancer Stem Cells

Cancer Stem Cells (CSC) generally constitute a minor cellular population within tumors that exhibits some capacities of normal Stem Cells (SC). The existence of CSC, able to self-renew and differentiate, influences central aspects of tumor biology, in part because they can continue tumor growth, give rise to metastasis, and acquire drug and radioresistance, which open new avenues for therapeutics. It is well known that SC constantly interacts with their niche, which includes mesenchymal cells, extracellular ligands, and the Extra Cellular Matrix (ECM). These interactions regularly lead to homeostasis and maintenance of SC characteristics. However, the exact participation of each of these components for CSC maintenance is not clear, as they appear to be context- or cell-specific. In the recent past, surface cellular markers have been fundamental molecular tools for identifying CSC and distinguishing them from other tumor cells. Importantly, some of these cellular markers have been shown to possess functional roles that affect central aspects of CSC. Likewise, some of these markers can participate in regulating the interaction of CSC with their niche, particularly the ECM. We focused this review on the molecular mechanisms of surface cellular markers commonly employed to identify CSC, highlighting the signaling pathways and mechanisms involved in CSC-ECM interactions, through each of the cellular markers commonly used in the study of CSC, such as CD44, CD133, CD49f, CD24, CXCR4, and LGR5. Their presence does not necessarily implicate them in CSC biology.

Radiation-Induced CXCL12 Upregulation via Histone Modification at the Promoter in the Tumor Microenvironment of Hepatocellular Carcinoma

Tumor cells can vary epigenetically during ionizing irradiation (IR) treatment. These epigenetic variegations can influence IR response and shape tumor aggressiveness. However, epigenetic disturbance of histones after IR, implicating in IR responsiveness, has been elusive. Here, we investigate whether altered histone modification after IR can influence radiation responsiveness. The oncogenic CXCL12 mRNA and protein were more highly expressed in residual cancer cells from a hepatoma heterotopic murine tumor microenvironment and coculture of human hepatoma Huh7 and normal IMR90 cells after radiation. H3K4 methylation was also enriched and H3K9 methylation was decreased at its promoter region. Accordingly, invasiveness and the subpopulation of aggressive CD133+/CD24- cells increased after IR. Histone demethylase inhibitor IOX1 attenuated CXCL12 expression and the malignant subpopulation, suggesting that responses to IR can be partially mediated via histone modifications. Taken together, radiation-induced histone alterations at the CXCL12 promoter in hepatoma cells are linked to CXCL12 upregulation and increased aggressiveness in the tumor microenvironment.

CXCR4 mutations affect presentation and outcomes in patients with Waldenström macroglobulinemia: A systematic review

Introduction: The genomic landscape of Waldenström macroglobulinemia (WM) is characterized by recurrent MYD88 (MYD88^L265P) and CXCR4 mutations (CXCR4^MUT), detected in 90% and 30% of cases, respectively. The role of CXCR4^MUT in clinical features and outcomes to therapy in WM patients is evolving. Areas covered: We performed a systematic review aimed at evaluating the prevalence of CXCR4^MUT in WM patients, and at assessing differences in clinical features and outcomes to therapy between WM patients with and without CXCR4^MUT. Seventeen studies were included in our analysis. The pooled prevalence of CXCR4^MUT in WM patients was 31%; 34% in MYD88^L265P and 5% in MYD88^WT patients. CXCR4^MUT were associated with higher serum IgM levels and higher risk of hyperviscosity than CXCR4^WT patients. Very good partial response (VGPR) and progression-free survival (PFS) rates to ibrutinib, with and without rituximab, appeared lower in CXCR4^MUT than in CXCR4^WT patients. Response and PFS rates were not affected by CXCR4^MUT status on patients treated with proteasome inhibitors. Expert opinion: Our systematic review shows that WM patients with CXCR4^MUT have specific clinical features and have lower response and PFS rates to BTK inhibitors. Our findings support standardization of CXCR4 testing and development of CXCR4-directed therapy.

Targeting the phosphoinositide 3-kinase/AKT pathways by small molecules and natural compounds as a therapeutic approach for breast cancer cells

The phosphoinositide 3-kinase/AKT/mTOR (PI3K/AkT/mTOR) pathway plays a pivotal role in the uncontrolled growth, migration and development of human breast cancer. The elevated expression of TGF-β1 increases the PI3K/AkT/mTOR activity in human breast cancer tissue and potentially motivates tumor metastasis and resistance to chemotherapy. Here, we investigated whether treatment with PI3K/AkT/mTOR dual inhibitor NVP-BEZ235 alone or in combination with caffeic acid phenyl ester (CAPE) could prevent TGF-β1 effects on breast cancer cells. MCF-7 human breast cancer cells were exposed to TGF-β1 for 14 days and then were treated with/without NVP-BEZ235 and/or CAPE. Cell viability, apoptosis, CXCR4 surface expression and mRNA levels of CXCR4 and TWIST-1 were analyzed in all treated groups. We found that treatment of human breast cancer cells with a combination of NVP-BEZ235 and CAPE increased induction of cellular death. Although flow cytometry analysis demonstrated that NVP-BEZ235 alone treatment reduced CXCR4 expression while increasing CXCR4 mRNA level; when NVP-BEZ235 was combined with CAPE, inhibition of CXCR4 surface expression and enhancement of CXCR4 mRNA expression was diminished. In addition, TWIST-1 mRNA expression was down regulated in samples treated with both NVP-BEZ235 and CAPE. These altogether signified that NVP-BEZ235 in combination with CAPE showed improved therapeutic efficacy in breast cancer cells by decreasing apoptotic resistance and reduction of CXCR4 and TWIST-1 expression at mRNA level could be one of mechanism of action.

Bone microenvironment signaling of cancer stem cells as a therapeutic target in metastatic prostate cancer

Prostate cancer (PCa) is one of the most prevalent cancers and the second leading cause of cancer death among US males. When diagnosed in an early disease stage, primary tumors of PCa may be treated with surgical resection or radiation, sometimes combined with androgen deprivation therapy, with favorable outcomes. Unfortunately, the treatment efficacy of each approach decreases significantly in later stages of PCa that involve metastasis to soft tissues and bone. Metastatic PCa is a heterogeneous disease containing host cells, mature cancer cells, and subpopulation of cancer stem cells (CSC). CSCs are highly tumorigenic due to their self-renewing and differentiating potential, clinically resulting in recurrence and resistance to standard therapies. Therefore, there is a large unmet clinical need to develop therapies, which target CSC activity. In this review, we summarize the main signaling pathways that are implicated in the current pre-clinical and clinical studies of recurrent metastatic PCa within the bone microenvironment targeting CSCs and discuss the trajectory of therapeutics moving forward.

Analysis of the high-dose-range radioresistance of prostate cancer cells, including cancer stem cells, based on a stochastic model

In radiotherapy, cancer stem cells (CSCs) are well recognized as one of the radioresistant cell types. Even in a small subpopulation, CSCs may have an influence on tumor control probability, represented by cell killing after irradiation. However, the relationship between the percentage content of CSCs and the cell survival dose-response curve has not yet been quantitatively clarified. In this study, we developed a cell-killing model for two cell populations (CSCs and progeny cells) to predict the surviving fractions, and compared it with the conventional linear-quadratic (LQ) model. Three prostate cancer cell lines (DU145, PC3 and LNCaP) were exposed to X-rays at doses ranging from 0 to 10 Gy. After the irradiation, we performed clonogenic survival assays to generate the cell survival curves, and carried out flow-cytometric analyses to estimate the percentage content of CSCs for each cell line. The cell survival curves for DU145 cells and PC3 cells seemed not to follow the conventional LQ model in the high dose range (>8 Gy). However, the outputs of the developed model agreed better with the experimental cell survival curves than those of the LQ model. The percentage content of CSCs predicted by the developed model was almost coincident with the measured percentage content for both DU145 cells and PC3 cells. The experiments and model analyses indicate that a small subpopulation of radioresistant CSCs has lower radiosensitivity in the high-dose range, which may lessen the clinical outcome for patients with prostate cancer after high-dose radiation therapy.

Semaphorin 3C as a Therapeutic Target in Prostate and Other Cancers

The semaphorins represent a large family of signaling molecules with crucial roles in neuronal and cardiac development. While normal semaphorin function pertains largely to development, their involvement in malignancy is becoming increasingly evident. One member, Semaphorin 3C (SEMA3C), has been shown to drive a number of oncogenic programs, correlate inversely with cancer prognosis, and promote the progression of multiple different cancer types. This report surveys the body of knowledge surrounding SEMA3C as a therapeutic target in cancer. In particular, we summarize SEMA3C's role as an autocrine andromedin in prostate cancer growth and survival and provide an overview of other cancer types that SEMA3C has been implicated in including pancreas, brain, breast, and stomach. We also propose molecular strategies that could potentially be deployed against SEMA3C as anticancer agents such as biologics, small molecules, monoclonal antibodies and antisense oligonucleotides. Finally, we discuss important considerations for the inhibition of SEMA3C as a cancer therapeutic agent.

CXCR4 and CCR7 Expression in Primary Nodal Diffuse Large B-Cell Lymphoma-A Clinical and Immunohistochemical Study

BACKGROUND

A few studies have evaluated the expression of chemokine receptors CXCR4 and CCR7 in diffuse large B-cell lymphoma (DLBCL); however, the association between CXCR4 and CCR7 with bone marrow (BM) involvement and their synergistic effect on prognosis is still unclear. Our study investigated this aspect.

METHODS

Specimens were obtained from 61 primary nodal DLBCL patients and 100 reactive proliferative lymphadenitis patients. CXCR4 and CCR7 expression levels were examined by immunohistochemical staining; the relationship between these levels and clinical parameters and the differences in overall survival were analyzed.

RESULTS

CXCR4 and CCR7 overexpression was observed in the malignant lymph node tissues from most DLBCL patients. CCR7 expression was significantly higher in the non-GCB than the GCB subtype; CXCR4 positivity rates showed no significant difference between the 2 subtypes. In DLBCL patients with BM involvement, CXCR4 was overexpressed in almost all BM samples, but CCR7 expression was low in BM. CXCR4 overexpression was associated with advanced Ann Arbor stages, MYC overexpression, and increased extranodal infiltration; CCR7 was associated with advanced Ann Arbor stages and elevated LDH. Like the case for CCR7, the survival rate of CXCR4-positive DLBCL patients was significantly lower than that of the CXCR4-negative patients. CXCR4⁺CCR7⁺ patients had the lowest survival rate.

CONCLUSIONS

There is a positive correlation between CXCR4 overexpression and BM involvement. CXCR4 and CCR7 overexpression is associated with poorer overall survival, especially in CXCR4 and CCR7 copositive patients. CXCR4, CCR7, Ki-67 index, and MYC were independent prognostic factors for DLBCL. Blocking CXCR4 and/or CCR7 can be a novel therapeutic strategy for DLBCL.

AMD3100 inhibits epithelial-mesenchymal transition, cell invasion, and metastasis in the liver and the lung through blocking the SDF-1α/CXCR4 signaling pathway in prostate cancer

Stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) have been found to be tightly correlated with the progression of prostate cancer (PC). In this study, we investigated the effects of an SDF-1α/CXCR4 inhibitor, AMD3100, on cell progression and metastasis potential of human PC cells. Human PC cell lines (LNCaP, PC3, and DU145) were cultured to detect SDF-1α/CXCR4, which showed higher SDF-1α and CXCR4 expression than the normal human prostate epithelial cell line, RWPE-1. AMD3100 was confirmed to be an inhibitor of SDF-1α, and to detect the effect of SDF-1α/CXCR4 inhibition on PC, PC cells were treated with AMD3100 or/and CXCR4 siRNA. The results suggested that inhibition of the SDF-1α/CXCR4 pathway could promote the E-cadherin level but inhibit the levels of invasion and migration of vimentin, N-cadherin and α5β1 integrin. Finally, tumor formation in nude mice was conducted, and the cell experiment results were verfied. These data show that AMD3100 suppresses epithelial-mesenchymal transition and migration of PC cells by inhibiting the SDF-1α/CXCR4 signaling pathway, which provides a clinical target in the treatment of PC.