Interleukin-4 induces a CD44high /CD49bhigh PC3 subpopulation with tumor-initiating characteristics

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.

Type II Interleukin-4 Receptor Activation in Basal Breast Cancer Cells Promotes Tumor Progression via Metabolic and Epigenetic Modulation

Interleukin-4 (IL4) is a Th2 cytokine that can signal through two different receptors, one of which-the type II receptor-is overexpressed by various cancer cells. Previously, we have shown that type II IL4 receptor signaling increases proliferation and metastasis in mouse models of breast cancer, as well as increasing glucose and glutamine metabolism. Here, we expand on those findings to determine mechanistically how IL4 signaling links glucose metabolism and histone acetylation to drive proliferation in the context of triple-negative breast cancer (TNBC). We used a combination of cellular, biochemical, and genomics approaches to interrogate TNBC cell lines, which represent a cancer type where high expression of the type II IL4 receptor is linked to reduced survival. Our results indicate that type II IL4 receptor activation leads to increased glucose uptake, Akt and ACLY activation, and histone acetylation in TNBC cell lines. Inhibition of glucose uptake through the deletion of Glut1 ablates IL4-induced proliferation. Additionally, pharmacological inhibition of histone acetyltransferase P300 attenuates IL4-mediated gene expression and proliferation in vitro. Our work elucidates a role for type II IL4 receptor signaling in promoting TNBC progression, and highlights type II IL4 signaling, as well as histone acetylation, as possible targets for therapy.

The Molecular Biology of Prostate Cancer Stem Cells: From the Past to the Future

Prostate cancer (PCa) continues to rank as the second leading cause of cancer-related mortality in western countries, despite the golden treatment using androgen deprivation therapy (ADT) or anti-androgen therapy. With decades of research, scientists have gradually realized that the existence of prostate cancer stem cells (PCSCs) successfully explains tumor recurrence, metastasis and therapeutic failure of PCa. Theoretically, eradication of this small population may improve the efficacy of current therapeutic approaches and prolong PCa survival. However, several characteristics of PCSCs make their diminishment extremely challenging: inherent resistance to anti-androgen and chemotherapy treatment, over-activation of the survival pathway, adaptation to tumor micro-environments, escape from immune attack and being easier to metastasize. For this end, a better understanding of PCSC biology at the molecular level will definitely inspire us to develop PCSC targeted approaches. In this review, we comprehensively summarize signaling pathways responsible for homeostatic regulation of PCSCs and discuss how to eliminate these fractional cells in clinical practice. Overall, this study deeply pinpoints PCSC biology at the molecular level and provides us some research perspectives.

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.

Tumor promoting roles of IL-10, TGF-β, IL-4, and IL-35: Its implications in cancer immunotherapy

Cytokines play a critical role in regulating host immune response toward cancer and determining the overall fate of tumorigenesis. The tumor microenvironment is dominated mainly by immune-suppressive cytokines that control effector antitumor immunity and promote survival and the proliferation of cancer cells, which ultimately leads to enhanced tumor growth. In addition to tumor cells, the heterogeneous immune cells present within the tumor milieu are the significant source of immune-suppressive cytokines. These cytokines are classified into a broad range; however, in most tumor types, the interleukin-10, transforming growth factor-β, interleukin-4, and interleukin-35 are consistently reported as immune-suppressive cytokines that help tumor growth and metastasis. The most emerging concern in cancer treatment is hijacking and restraining the activity of antitumor immune cells in the tumor niche due to a highly immune-suppressive environment. This review summarizes the role and precise functions of interleukin-10, transforming growth factor-β, interleukin-4, and interleukin-35 in modulating tumor immune contexture and its implication in developing effective immune-therapeutic approaches.

CONCISE CONCLUSION

Recent effort geared toward developing novel immune-therapeutic approaches faces significant challenges due to sustained mutations in tumor cells and a highly immune-suppressive microenvironment present within the tumor milieu. The cytokines play a crucial role in developing an immune-suppressive environment that ultimately dictates the fate of tumorigenesis. This review critically covers the novel aspects of predominant immune-suppressive cytokines such as interleukin-10, transforming growth factor-β, interleukin-4, and interleukin-35 in dictating the fate of tumorigenesis and how targeting these cytokines can help the development of better immune-therapeutic drug regimens for the treatment of cancer.

IL-4 Counteracts the Cytotoxic Effects of Peripheral Blood Mononuclear Cells on Hormone-sensitive Prostate Cancer Cells

BACKGROUND/AIM

Proinflammatory cytokines play an essential role in the development and progression of prostate cancer (PCa). Especially interleukine (IL-)6 is involved in the development of aggressive PCa. Peripheral blood mononuclear cells (PBMC) have been reported to interact with cancer cells and subsequently lead to increased production of pro-inflammatory cytokines. However, the role of anti-nflammatory cytokines, such as IL-4 is still largely unexplored in prostate cancer. In the present study, we investigated the effects of IL-4 on PBMC co-cultured with PCa cells.

MATERIALS AND METHODS

PBMC were co-culured with the PCa cell lines LNCaP and LNCaP-IL6+. To avoid cell-cell contact, cancer and immune cells were separated using cell culture inserts with a 0.4 μm pore size membrane. Cell growth was assessed using the [3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium bromide] (MTT) assay. Cytokine levels were measured using a BD™Cytometric Bead Array.

RESULTS

Cell viability of LNCaP cells decreased massively when cells were co-cultured with PBMC. Pre-incubation with IL-4 could partly rescue the observed effect of cell viability of LNCaP cells co-cultured with PBMC. In contrast, cell viability of the LNCaP-IL6+ cell line was not affected when co-cultured with PBMC.

CONCLUSION

IL-4 counteracts the cytotoxic effects of PBMC on hormone-sensitive LNCaP cells and is involved in the immune escape and development of aggressive phenotypes of PCa.

Involvement of IL-4, IL-13 and Their Receptors in Pancreatic Cancer

Interleukin (IL)-4 and IL-13 are known as pleiotropic Th2 cytokines with a wide range of biological properties and functions especially in immune responses. In addition, increasing activities have also been determined in oncogenesis and tumor progression of several malignancies. It is now generally accepted that IL-4 and IL-13 can exert effects on epithelial tumor cells through corresponding receptors. Type II IL-4 receptor (IL-4Rα/IL-13Rα1), predominantly expressed in non-hematopoietic cells, is identified to be the main target for both IL-4 and IL-13 in tumors. Moreover, IL-13 can also signal by binding to the IL-13Rα2 receptor. Structural similarity due to the use of the same receptor complex generated in response to IL-4/IL-13 results in overlapping but also distinct signaling pathways and functions. The aim of this review was to summarize knowledge about IL-4 and IL-13 and their receptors in pancreatic cancer in order understand the implication of IL-4 and IL-13 and their receptors for pancreatic tumorigenesis and progression and for developing possible new diagnostic and therapeutic targets.

CD44 as a tumor biomarker and therapeutic target

CD44, a complex transmembrane glycoprotein, exists in multiple molecular forms, including the standard isoform CD44s and CD44 variant isoforms. CD44 participates in multiple physiological processes, and aberrant expression and dysregulation of CD44 contribute to tumor initiation and progression. CD44 represents a common biomarker of cancer stem cells, and promotes epithelial-mesenchymal transition. CD44 is involved in the regulation of diverse vital signaling pathways that modulate cancer proliferation, invasion, metastasis and therapy-resistance, and it is also modulated by a variety of molecules in cancer cells. In addition, CD44 can serve as an adverse prognostic marker among cancer population. The pleiotropic roles of CD44 in carcinoma potentially offering new molecular target for therapeutic intervention. Preclinical and clinical trials for evaluating the pharmacokinetics, efficacy and drug-related toxicity of CD44 monoclonal antibody have been carried out among tumors with CD44 expression. In this review, we focus on current data relevant to CD44, and outline CD44 structure, the regulation of CD44, functional properties of CD44 in carcinogenesis and cancer progression as well as the potential CD44-targeting therapy for cancer management.

PIM protein kinases regulate the level of the long noncoding RNA H19 to control stem cell gene transcription and modulate tumor growth

The proviral integration site for Moloney murine leukemia virus (PIM) serine/threonine kinases have an oncogenic and prosurvival role in hematological and solid cancers. However, the mechanism by which these kinases drive tumor growth has not been completely elucidated. To determine the genes controlled by these protein kinases, we carried out a microarray analysis in T-cell acute lymphoblastic leukemia (T-ALL) comparing early progenitor (ETP-ALL) cell lines whose growth is driven by PIM kinases to more mature T-ALL cells that have low PIM levels. This analysis demonstrated that the long noncoding RNA (lncRNA) H19 was associated with increased PIM levels in ETP-ALL. Overexpression or knockdown of PIM in these T-ALL cell lines controlled the level of H19 and regulated the methylation of the H19 promoter, suggesting a mechanism by which PIM controls H19 transcription. In these T-ALL cells, the expression of PIM1 induced stem cell gene expression (SOX2, OCT-4, and NANOG) through H19. Identical results were found in prostate cancer (PCa) cell lines where PIM kinases drive cancer growth, and both H19 and stem cell gene levels. Small molecule pan-PIM inhibitors (PIM-i) currently in clinical trials reduced H19 expression in both of these tumor types. Importantly, the knockdown of H19 blocked the ability of PIM to induce stem cell genes in T-ALL cells, suggesting a novel signal transduction cascade. In PCa, increases in SOX2 levels have been shown to cause both resistance to the androgen deprivation therapy (ADT) and the induction of neuroendocrine PCa, a highly metastatic form of this disease. Treatment of PCa cells with a small molecule pan-PIM-i reduced stem cell gene transcription and enhanced ADT, while overexpression of H19 suppressed the ability of pan-PIM-i to regulate hormone blockade. Together, these results demonstrate that the PIM kinases control the level of lncRNA H19, which in turn modifies stem cell gene transcription regulating tumor growth.

Cancer stem cells in esophageal squamous cell cancer

Cancer stem cells (CSCs) are hypothesized to govern the origin, progression, drug resistance, recurrence and metastasis of human cancer. CSCs have been identified in nearly all types of human cancer, including esophageal squamous cell cancer (ESCC). Four major methods are typically used to isolate or enrich CSCs, including: i) fluorescence-activated cell sorting or magnetic-activated cell sorting using cell-specific surface markers; ii) stem cell markers, including aldehyde dehydrogenase 1 family member A1; iii) side population cell phenotype markers; and iv) microsphere culture methods. ESCC stem cells have been identified using a number of these methods. An increasing number of stem cell signatures and pathways have been identified, which have assisted in the clarification of molecular mechanisms that regulate the stemness of ESCC stem cells. Certain viruses, such as human papillomavirus and hepatitis B virus, are also considered to be important in the formation of CSCs, and there is a crosstalk between stemness and viruses-associated genes/pathways, which may suggest a potential therapeutic strategy for the eradication of CSCs. In the present review, findings are summarized along these lines of inquiry.

Epithelial-To-Mesenchymal Transition Markers and CD44 Isoforms Are Differently Expressed in 2D and 3D Cell Cultures of Prostate Cancer Cells

Three-dimensional (3D) cell cultures allow the mimic of functions of living tissues and provide key information encoded in tissue architecture. Considered the pivotal role of epithelial-to-mesenchymal transition (EMT) in carcinoma progression, including prostate cancer (PCa), we aimed at investigating the effect of the 3D arrangement on the expression of some key markers of EMT in cultured human prostate cancer (PCa) cells, to better understand PCa cell behavior. PC3 and DU145 PCa cells were cultured in RPMI cell culture medium either in 2D-monolayers or in 3D-spheroids. The main EMT markers E-cadherin, N-cadherin, α-smooth muscle actin (αSMA), vimentin, Snail, Slug, Twist and Zeb1 were evaluated by confocal microscopy, real-time PCR and Western blot. Confocal microscopy revealed that E-cadherin was similarly expressed at the cell boundaries on the plasma membrane of PCa cells grown in 2D-monolayers, as well as in 3D-spheroids, but resulted up-regulated in 3D-spheroids, compared to 2D-monolayers, at the mRNA and protein level. Moreover, markers of the mesenchymal phenotype were expressed at very low levels in 3D-spheroids, suggesting important differences in the phenotype of PCa cells grown in 3D-spheroids or in 2D-monolayers. Considered as a whole, our findings contribute to a clarification of the role of EMT in PCa and confirm that a 3D cell culture model could provide deeper insight into the understanding of the biology of PCa.

Interleukin-4 induces a CD44high /CD49bhigh PC3 subpopulation with tumor-initiating characteristics

Pro‐ and anti‐inflammatory cytokines may influence proliferation, migration, invasion, and other cellular events of prostate cancer (PCa) cells. The hyaluronan receptor CD44, which is regulated by Interleukin (IL)‐4, is a prostate basal cell marker. CD44_high/CD49b_high expressing cells have been demonstrated to have tumor‐initiating characteristics. Here, we aimed to analyze the effects of long‐term IL‐4 treatment on CD44/CD49b expression, migration, proliferation, and clonogenic potential of basal‐like PCa cells. To this end PC3 cells were treated over 30 passages with 5 ng/mL IL‐4 (PC3‐IL4) resulting in an increased population of CD44_high expressing cells. This was concurrent with a clonal outgrowth of cuboid‐shaped cells, with increased size and light absorbance properties. Flow cytometry revealed that the PC3‐IL4 CD44_high expressing subpopulation corresponds to the CD49b_high population. Isolation of the PC3‐IL4 CD44_high/CD49b_high subpopulation via fluorescence‐associated cell sorting showed increased migrative, proliferative, and clonogenic potential compared to the CD44_low/CD49b_low subpopulation. In conclusion, IL‐4 increases a PC3 subpopulation with tumor‐initiating characteristics. Thus, IL‐4, similar to other cytokines may be a regulator of tumor‐initiation and hence, may present a suitable therapy target in combination with current treatment options.