cmvIL-10 stimulates the invasive potential of MDA-MB-231 breast cancer cells

Cytokine levels in breast cancer are highly dependent on cytomegalovirus (CMV) status

PURPOSE

Breast cancer accounts for 30% of all female cancers in the US. Cytomegalovirus (CMV), a herpesvirus that establishes lifelong infection, may play a role in breast cancer. CMV is not oncogenic, yet viral DNA and proteins have been detected in breast tumors, indicating possible contribution to tumor development. CMV encodes cmvIL-10, a homolog of human cellular IL-10 (cIL-10) with potent immunosuppressive activities. We investigated the relationship between CMV infection, cytokines, and breast cancer.

METHODS

We evaluated CMV serostatus and cytokine levels in plasma of women with benign breast disease (n = 38), in situ carcinoma (n = 41), invasive carcinoma, no lymph node involvement (Inv/LN-; n = 41), and invasive with lymph node involvement (Inv/LN+; n = 37).

RESULTS

Fifty percent of the patient samples (n = 79) were CMV seropositive. There was no correlation between CMV status and diagnosis (p = 0.75). For CMV+ patients, there was a trend toward higher CMV IgG levels in invasive disease (p = 0.172). CmvIL-10 levels were higher in CMV+ in situ patients compared to the Inv/LN- and Inv/LN+ groups (p = 0.020). Similarly, cIL-10 levels were higher in CMV+ in situ patients compared to the Inv/LN- and Inv/LN+ groups (p = 0.043). The results were quite different in CMV- patients where cIL-10 levels were highest in Inv/LN- compared to benign, in situ, or Inv/LN+ (p = 0.019). African American patients were significantly associated with CMV+ status (p = 0.001) and had lower cmvIL-10 levels than Caucasian patients (p = 0.046).

CONCLUSION

No association was observed between CMV IgG and diagnosis, but CMV infection influences cytokine production and contributes to altered cytokine profiles in breast cancer.

CircRNA LOC729852 promotes bladder cancer progression by regulating macrophage polarization and recruitment via the miR-769-5p/IL-10 axis

Circular RNAs (circRNAs) function as tumour promoters or suppressors in bladder cancer (BLCA) by regulating genes involved in macrophage recruitment and polarization. However, the underlying mechanisms are largely unknown. The aim of this study was to determine the biological role of circLOC729852 in BLCA. CircLOC729852 was upregulated in BLCA tissues and correlated with increased proliferation, migration and epithelial mesenchymal transition (EMT) of BCLA cells. MiR-769-5p was identified as a target for circLOC729852, which can upregulate IL-10 expression by directly binding to and suppressing miR-769-5p. Furthermore, our results indicated that the circLOC729852/miR-769-5p/IL-10 axis modulates autophagy signalling in BLCA cells and promotes the recruitment and M2 polarization of TAMs by activating the JAK2/STAT3 signalling pathway. In addition, circLOC729852 also promoted the growth of BLCA xenografts and M2 macrophage infiltration in vivo. Thus, circLOC729852 functions as an oncogene in BLCA by inducing secretion of IL-10 by the M2 TAMs, which then facilitates tumour cell growth and migration. Taken together, circLOC729852 is a potential diagnostic biomarker and therapeutic target for BLCA.

Tumors and Cytomegalovirus: An Intimate Interplay

Human cytomegalovirus (HCMV) is a herpesvirus that alternates lytic and latent infection, infecting between 40 and 95% of the population worldwide, usually without symptoms. During its lytic cycle, HCMV can result in fever, asthenia, and, in some cases, can lead to severe symptoms such as hepatitis, pneumonitis, meningitis, retinitis, and severe cytomegalovirus disease, especially in immunocompromised individuals. Usually, the host immune response keeps the virus in a latent stage, although HCMV can reactivate in an inflammatory context, which could result in sequential lytic/latent viral cycles during the lifetime and thereby participate in the HCMV genomic diversity in humans and the high level of HCMV intrahost genomic variability. The oncomodulatory role of HCMV has been reported, where the virus will favor the development and spread of cancerous cells. Recently, an oncogenic role of HCMV has been highlighted in which the virus will directly transform primary cells and might therefore be defined as the eighth human oncovirus. In light of these new findings, it is critical to understand the role of the immune landscape, including the tumor microenvironment present in HCMV-harboring tumors. Finally, the oncomodulatory/oncogenic potential of HCMV could lead to the development of novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies and new therapeutic approaches are actively needed, particularly to fight tumors of poor prognosis.

PDGFRα Enhanced Infection of Breast Cancer Cells with Human Cytomegalovirus but Infection of Fibroblasts Increased Prometastatic Inflammation Involving Lysophosphatidate Signaling

Human cytomegalovirus (HCMV) infects 40-70% of adults in developed countries. HCMV proteins and DNA are detected in tumors and metastases, suggesting an association with increased invasion. We investigated HCMV infection in human breast cancer cell lines compared to fibroblasts, a component of tumors, and the role of platelet-derived growth factor receptor-α (PDGFRα). HCMV productively infected HEL299 fibroblasts and, to a lesser extent, Hs578T breast cancer cells. Infection of another triple-negative cell line, MDA-MB-231, and also MCF-7 cells, was extremely low. These disparate infection rates correlated with expression of PDGFRA, which facilitates HCMV uptake. Increasing PDGFRA expression in T-47D breast cancer and BCPAP thyroid cancer cells markedly increased HCMV infection. Conversely, HCMV infection decreased PDGFRA expression, potentially attenuating signaling through this receptor. HCMV infection of fibroblasts promoted the secretion of proinflammatory factors, whereas an overall decreased secretion of inflammatory factors was observed in infected Hs578T cells. We conclude that HCMV infection in tumors will preferentially target tumor-associated fibroblasts and breast cancer cells expressing PDGFRα. HCMV infection in the tumor microenvironment, rather than cancer cells, will increase the inflammatory milieu that could enhance metastasis involving lysophosphatidate.

Immune Landscape of CMV Infection in Cancer Patients: From "Canonical" Diseases Toward Virus-Elicited Oncomodulation

Human Cytomegalovirus (HCMV) is an immensely pervasive herpesvirus, persistently infecting high percentages of the world population. Despite the apparent robust host immune responses, HCMV is capable of replicating, evading host defenses, and establishing latency throughout life by developing multiple immune-modulatory strategies. HCMV has coexisted with humans mounting various mechanisms to evade immune cells and effectively win the HCMV-immune system battle mainly through maintaining its viral genome, impairing HLA Class I and II molecule expression, evading from natural killer (NK) cell-mediated cytotoxicity, interfering with cellular signaling, inhibiting apoptosis, escaping complement attack, and stimulating immunosuppressive cytokines (immune tolerance). HCMV expresses several gene products that modulate the host immune response and promote modifications in non-coding RNA and regulatory proteins. These changes are linked to several complications, such as immunosenescence and malignant phenotypes leading to immunosuppressive tumor microenvironment (TME) and oncomodulation. Hence, tumor survival is promoted by affecting cellular proliferation and survival, invasion, immune evasion, immunosuppression, and giving rise to angiogenic factors. Viewing HCMV-induced evasion mechanisms will play a principal role in developing novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies. Since tumors acquire immune evasion strategies, anti-tumor immunity could be prominently triggered by multimodal strategies to induce, on one side, immunogenic tumor apoptosis and to actively oppose the immune suppressive microenvironment, on the other side.

Apoptosis Disorder, a Key Pathogenesis of HCMV-Related Diseases

Human cytomegalovirus (HCMV) belongs to the β-herpesvirus family, which is transmitted in almost every part of the world and is carried by more than 90% of the general population. Increasing evidence indicates that HCMV infection triggers numerous diseases by disrupting the normal physiological activity of host cells, particularly apoptosis. Apoptosis disorder plays a key role in the initiation and development of multiple diseases. However, the relationship and molecular mechanism of HCMV-related diseases and apoptosis have not yet been systematically summarized. This review aims to summarize the role of apoptosis in HCMV-related diseases and provide an insight into the molecular mechanism of apoptosis induced by HCMV infection. We summarize the literature on HCMV-related diseases and suggest novel strategies for HCMV treatment by regulating apoptosis.

Human cytomegalovirus protein UL136 activates the IL-6/STAT3 signal through MiR-138 and MiR-34c in gastric cancer cells

BACKGROUND

Accumulating evidences have indicated that human cytomegalovirus (HCMV) may link to multiple human malignancies, including gastric cancer. However, the mechanistic role of HCMV in GC remains largely unknown.

METHODS

In this study, we have successfully established HCMV latent gene UL-136-expressing gastric cancer cells. We measured cell proliferation of GC cells, MNK-45 and SGC-7901, with stable UL136 expression or paired control cells by using CCK-8 assay. We have showed that GC cells with stable UL136 expression had a rapid cell growth. Furthermore, our data from matrigel-coated transwell assay have demonstrated that UL136 expressing GC cells showed an enhanced invasion capacity compared to control cells. Furthermore, ectopic expression of UL136 inhibits tumorigenicity in an animal model.

RESULTS

We observed that IL-6/STAT3 was stimulated by UL136 overexpression. Also, miR-138 is consistently up-regulated, while miR-34 down-regulated by UL136 in either MNK-45 or SGC-7901 cells. Our mechanistic study showed that treatment of miR-138 mimics in MNK-45 cells indeed inhibited SIRT1 expression to increase phosphorylation level of STAT3. MiR-34c suppressed expression of IL6R through direct binding with the putative 3'UTR binding sites of this gene. UL136 regulate IL6/STAT3 pathway, at least in part, through down-regulation of miR-34c in GC cells.

CONCLUSION

In conclusion, HCMV-induced miR-34c or miR-138 involves in the activation of IL6/STAT3 signaling. Targeting the IL6-STAT3 axis or miRNAs represent a promising strategy for HCMV-related tumor formation.

Toll-like receptor (TLR) gene expression and immunostimulatory effect of CpG oligonucleotides in hormone receptor positive cell line T47D and triple negative breast cancer cell line MDA-MB-468

BACKGROUND

We investigated the expression of TLR genes and the effects of CpG ODN in Estrogen Receptor positive, Progesterone Receptor positive breast cancer cell line (T47D) and a triple-negative breast cancer cell line (MDA-MB-468) followed by studying the immunostimulatory activity of CpG oligonucleotides in breast cancer cell lines T47D and MDA-MB-468.

MATERIALS AND METHODS

We evaluated the expression pattern of TLR genes (TLR1 to TLR9) in T47D and MDA-MB-468 cells using Real-time qPCR analysis. The intracellular TLR9 protein expression was studied by flow cytometry. The effect of CpG ODN on cell viability was tested using MTT assay. The relative expression of pro-inflammatory (IL6 and TNFα) and anti- inflammatory/immunosuppressive cytokines genes (IL10 and TGF beta1) were examined by Real-time qPCR.

RESULTS

We found that MDA-MB-468 cells expressed TLR2, TLR3, TLR6, TLR8, and TLR9 genes and T47D cells expressed TLR3, TRL5, TLR8, and TLR9 genes. Stimulation of TLR9 in vitro with CpG significantly reduced the cell viability of T47D and MDA-MB-468 cells. IL6 cytokine gene expression was significantly reduced in both CpG treated T47D cells and MDA-MB-468 cells. TNFα gene expression was significantly reduced after treatment with CpG in MDA-MB-468 cells but not in T47D cells. IL10 and TGFβ1 expression were downregulated in CpG treated T47D cells. Whereas, IL10 and TGFβ1 were elevated in CpG treated MDA-MB-468 cells.

CONCLUSION

Our in vitro finding gives preliminary evidence that triggering TLR9 using CpG ODN decreases the cell proliferation and alters the pro-inflammatory cytokines in favor of inhibition of hormone receptor positive breast cancer cells T47D and triple negative breast cancer cells MDA-MB-468.

Human Cytomegalovirus Interleukin 10 Homologs: Facing the Immune System

Human Cytomegalovirus (HCMV) can cause a variety of health disorders that can lead to death in immunocompromised individuals and neonates. The HCMV lifecycle comprises both a lytic (productive) and a latent (non-productive) phase. HCMV lytic infection occurs in a wide range of terminally differentiated cell types. HCMV latency has been less well-studied, but one characterized site of latency is in precursor cells of the myeloid lineage. All known viral genes are expressed during a lytic infection and a subset of these are also transcribed during latency. The UL111A gene which encodes the viral IL-10, a homolog of the human IL-10, is one of these genes. During infection, different transcript isoforms of UL111A are generated by alternative splicing. The most studied of the UL111A isoforms are cmvIL-10 (also termed the "A" transcript) and LAcmvIL-10 (also termed the "B" transcript), the latter being a well-characterized latency associated transcript. Both isoforms can downregulate MHC class II, however they differ in a number of other immunomodulatory properties, such as the ability to bind the IL10 receptor and induce signaling through STAT3. There are also a number of other isoforms which have been identified which are expressed by differential splicing during lytic infection termed C, D, E, F, and G, although these have been less extensively studied. HCMV uses the viral IL-10 proteins to manipulate the immune system during lytic and latent phases of infection. In this review, we will discuss the literature on the viral IL-10 transcripts identified to date, their encoded proteins and the structures of these proteins as well as the functional properties of all the different isoforms of viral IL-10.

Arctigenin Enhances the Cytotoxic Effect of Doxorubicin in MDA-MB-231 Breast Cancer Cells

Several reports have described the anti-cancer activity of arctigenin, a lignan extracted from Arctium lappa L. Here, we investigated the effect of arctigenin (ATG) on doxorubicin (DOX)-induced cell death using MDA-MB-231 human breast cancer cells. The results showed that DOX-induced cell death was enhanced by ATG/DOX co-treatment in a concentration-dependent manner and that this was associated with increased DOX uptake and the suppression of multidrug resistance-associated protein 1 (MRP1) gene expression in MDA-MB-231 cells. ATG enhanced DOX-induced DNA damage and decreased the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the expressions of RAD51 and survivin. Cell death caused by ATG/DOX co-treatment was mediated by the nuclear translocation of apoptosis inducing factor (AIF), reductions in cellular and mitochondrial Bcl-2 and Bcl-xL, and increases in mitochondrial BAX levels. However, caspase-3 and -7 did not participate in DOX/ATG-induced cell death. We also found that DOX/ATG-induced cell death was linked with activation of the p38 signaling pathway and suppressions of the phosphorylations and expressions of Akt and c-Jun N-terminal kinase. Taken together, these results show that ATG enhances the cytotoxic activity of DOX in MDA-MB-231 human breast cancer cells by inducing prolonged p21 expression and p38-mediated AIF-dependent cell death. In conclusion, our findings suggest that ATG might alleviate the side effects and improve the therapeutic efficacy of DOX.

LLY17, a novel small molecule STAT3 inhibitor induces apoptosis and suppresses cell migration and tumor growth in triple-negative breast cancer

PURPOSE

Persistent STAT3 signaling is frequently detected in many cancer types including triple-negative breast cancer, and thus could potentially serve as a viable therapeutic target. We have designed a novel non-peptide compound LLY17 targeting STAT3 using Advanced Multiple Ligand Simultaneous Docking (AMLSD) methods. However, the efficacy of LLY17 has not been evaluated extensively in human and murine triple-negative breast cancer cells. In this study, we tested LLY17 in multiple human and murine triple-negative breast cancer cell lines.

METHODS

Human triple-negative breast cancer MDA-MB-468, MDA-MB-231, SUM159, and BT-549 cells, and murine triple-negative breast cancer 4T1 cells were used to study the inhibition effects of LLY17. The inhibition of STAT3 activation of LLY17 was investigated using western blot analysis. Cell viability, apoptosis and migration assays were carried out by MTT assay, Caspase-3/7 assay and wound healing assay, respectively. A mammary fat pad syngeneic mouse model was used to evaluate the antitumor effect of LLY17 in vivo.

RESULTS

LLY17 inhibited IL-6-mediated induction of STAT3 phosphorylation but had no effect on IFN-γ-induced STAT1 phosphorylation or EGF-induced ERK phosphorylation. LLY17 inhibited STAT3 phosphorylation and induced apoptosis in human and murine triple-negative breast cancer cells but exhibited minimal toxicity toward Luminal A subtype breast cancer MCF-7 cells. RNAi attenuation experiments supported the requirement of STAT3 for LLY17-mediated inhibition of cell viability in triple-negative breast cancer cells. In addition, LLY17 inhibited cell migration of human and murine triple-negative breast cancer cells. Furthermore, LLY17 suppressed tumor growth and STAT3 phosphorylation of triple-negative breast cancer cells in a mammary fat pad syngeneic mouse model in vivo.

CONCLUSIONS

Together, our findings suggest that targeting persistent STAT3 signaling by novel small molecule LLY17 may be a potential approach for the therapy of triple-negative breast cancer.

Ceramide and palmitic acid inhibit macrophage-mediated epithelial-mesenchymal transition in colorectal cancer

Accumulating evidence indicates that ceramide (Cer) and palmitic acid (PA) possess the ability to modulate switching of macrophage phenotypes and possess anti-tumorigenic effects; however, the underlying molecular mechanisms are largely unknown. The aim of the present study was to investigate whether Cer and PA could induce switching of macrophage polarization from the tumorigenic M2- towards the pro-inflammatory M1-phenotype, and whether this consequently altered the potential of colorectal cancer cells to undergo epithelial–mesenchymal transition (EMT), a hallmark of tumor progression. Our study showed that Cer- and PA-treated macrophages increased expression of the macrophage 1 (M1)-marker CD68 and secretion of IL-12 and attenuated expression of the macrophage 2 (M2)-marker CD163 and IL-10 secretion. Moreover, Cer and PA abolished M2 macrophage-induced EMT and migration of colorectal cancer cells. At the molecular level, this coincided with inhibition of SNAI1 and vimentin expression and upregulation of E-cadherin. Furthermore, Cer and PA attenuated expression levels of IL-10 in colorectal cancer cells co-cultured with M2 macrophages and downregulated STAT3 and NF-κB expression. For the first time, our findings suggest the presence of an IL-10-STAT3-NF-κB signaling axis in colorectal cancer cells co-cultured with M2 macrophages, mimicking the tumor microenvironment. Importantly, PA and Cer were powerful inhibitors of this signaling axis and, consequently, EMT of colorectal cancer cells. These results contribute to our understanding of the immunological mechanisms that underlie the anti-tumorigenic effects of lipids for future combination with drugs in the therapy of colorectal carcinoma.

Overexpression of the human cytomegalovirus UL111A is correlated with favorable survival of patients with gastric cancer and changes T-cell infiltration and suppresses carcinogenesis

Purpose

We previously found that human cytomegalovirus (HCMV) infection is associated with gastric cancer (GC) development. UL111A plays a role during HCMV productive or latent infection. However, UL111A expression profiles in GC tissues and their relationship with this disease are unknown.

Methods

PCR and nested RT-PCR were performed to verify UL111A expression in 71 GC tissues and its transcripts in 16 UL111A-positive GC samples. UL111A expression levels in GC patients were evaluated by immunohistochemistry on a tissue microarray for 620 GC patients. The correlations among UL111A expression levels, clinicopathological characteristics, and prognosis were analyzed. Further, the effects of overexpression of latency-associated viral interleukin-10 (LAcmvIL-10) and cmvIL-10 on GC cell proliferation, colony formation, migration, and invasion were assessed.

Results

The UL111A detection rate in GC tissues was 32.4% (23/71) and that of its mRNA expression was 68.75% (11/16). High expression of UL111A was also related to better overall and disease-free survival in GC patients. GC patients with TNM II/III stage expressing higher UL111A levels might benefit from adjuvant chemotherapy (ACT) after surgery. Moreover, high UL111A expression was also associated with increased CD4+ , CD8+ T-lymphocyte and Foxp3+ T-cell infiltration. In vitro assays further demonstrated that LAcmvIL-10 and cmvIL-10 overexpression inhibits GC cell line proliferation, colony formation, migration, and invasion.

Conclusions

High UL111A expression changes the number of infiltrating T cells and is associated with favorable survival. Therefore, UL111A could be used as an independent prognostic biomarker and might be a potential therapeutic target for GC.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-03092-x) contains supplementary material, which is available to authorized users.

Cytomegalovirus is a tumor-associated virus: armed and dangerous

Human cytomegalovirus (HCMV) gene products are present in multiple human malignancies, often in specific association with tumor cells and tumor vasculature. Emerging evidence from human and mouse models of CMV infection in cancer indicate that CMV can transform epithelial cells, promote epithelial to mesenchymal transition (EMT) and mesenchymal to epithelial (MET) in tumor cells, promote tumor angiogenesis and proliferation and incapacitate the host anti-CMV immune response. This review will discuss the increasing role of HCMV in human cancer by demonstrating how HCMV is well suited for impacting major themes in oncogenesis including initiation, promotion, progression, metastasis and immune evasion. What emerges is a picture of an extremely versatile pathogen that may play a significant role in human cancer progression and death.

The Human Cytomegalovirus, from Oncomodulation to Oncogenesis

Besides its well-described impact in immunosuppressed patients, the role of human cytomegalovirus (HCMV) in the pathogenesis of cancer has been more recently investigated. In cancer, HCMV could favor the progression and the spread of the tumor, a paradigm named oncomodulation. Although oncomodulation could account for part of the protumoral effect of HCMV, it might not explain the whole impact of HCMV infection on the tumor and the tumoral microenvironment. On the contrary cases have been reported where HCMV infection slows down the progression and the spread of the tumor. In addition, HCMV proteins have oncogenic properties per se, HCMV activates pro-oncogenic pathways in infected cells, and recently the direct transformation of cells following HCMV infection has been described, which gave rise to tumors when injected in mice. Thus, beyond the oncomodulation model, this review will assess the direct transforming role of HMCV-infected cells and the potential classification of HCMV as an oncovirus.

Impact of human cytomegalovirus on glioblastoma cell viability and chemotherapy treatment

The relationship between human cytomegalovirus (HCMV) and tumours has been extensively investigated, mainly in glioblastoma multiforme (GBM), a malignant tumour of the central nervous system with low overall survival rates. Several reports have demonstrated the presence of HCMV in GBM, although typically restricted to a low number of cells, and studies have indicated that viral proteins have the ability to dysregulate cellular processes and increase tumour malignancy. Treatment of GBM involves the use of the chemotherapeutic agents temozolomide (TMZ) and carmustine (bis-chloroethylnitrosourea, BCNU), which lead to the attachment of adducts to the DNA backbone, causing errors during replication and consequent cell death. It is known that HCMV infection can modulate DNA repair pathways, but what effects the virus may exhibit during chemotherapy are unknown. Here we approach this question by analysing HCMV infection and viral protein accumulation in GBM cell lines with different genotypes and their response to TMZ and BCNU in the presence of the virus. We demonstrate that A172, TP365MG and U251MG GBM cells are efficiently infected by both low-passage (TB40E) and high-passage (AD169) HCMV strains. However, the GBM cell lines vary widely in their permissiveness to viral gene expression and exhibit very different patterns of immediate early, early and late protein accumulation. HCMV reduces the viability of permissive GBM cells in a multiplicity-dependent manner in both the absence and presence of TMZ or BNCU. In sum, we demonstrate that GBM cell lines are equally susceptible but differentially permissive to infection by both low- and high-passage strains of HCMV. This observation not only indicates that viral replication is largely controlled by cellular factors in this system, but also provides a possible explanation for why viral gene products are only found in a subset of cells in GBM tumours. Furthermore, we conclude that the virus does not confer increased resistance to chemotherapeutic drugs in various GBM cell lines, but instead reduces tumour cell viability. These results highlight that the oncomodulatory potential of HCMV is not limited to cancer-promoting activities, but also includes adverse effects on tumour cell proliferation or survival.

Detection of Human Cytomegalovirus in Malignant and Benign Breast Tumors in Egyptian Women

INTRODUCTION

Previous studies have reported a role for human cytomegalovirus (HCMV) in breast carcinogenesis. We sought to assess the role of HCMV infection in the development and/or progression of breast cancer (BC) among Egyptian patients.

PATIENTS AND METHODS

The study included 61 patients with BC cases. Of these 61 patients, 40 had been assessed for HCMV in the blood, BC tissue samples, and adjacent non-neoplastic tissue samples, and 21 had been assessed for HCMV in the tissue only. Tissue samples from 20 patients with fibroadenoma (FA) were also included. As a control group, 41 blood samples obtained from healthy women with no history of cancer were used as a blood control group. HCMV was assessed using enzyme-linked immunosorbent assay, real-time polymerase chain reaction (PCR), and immunohistochemistry (IHC).

RESULTS

A significant difference was found in the index value for the anti-CMV IgG antibodies between the BC patients and the control group (P = .001). Using real-time PCR, HCMV DNA was detected in 11 of 61 BC tissues (18%) compared with 1 of 20 FA tissues (5%). HCMV DNA was present in 8 of the 40 plasma samples (20%). Regarding the viral proteins, 21 of 61 samples (34.4%) were positive for early/immediate early (E/IE) and 49 (80.3%) were positive for PP65 expression by IHC. The concordance between the results obtained by the different assays was low. CMVPP65 expression was significantly associated with E/IE protein expression in the malignant and FA groups (P < .001).

CONCLUSION

The presence of CMV proteins and DNA in BC tissues suggests a role for this virus. However, the basic criteria to support a causal association of HCMV with BC were not fulfilled.

Human cytomegalovirus interleukin-10 enhances matrigel invasion of MDA-MB-231 breast cancer cells

BACKGROUND

While some risk factors for breast cancer are well-known, the influence of other factors, particularly virus infection, remains unclear. Human cytomegalovirus (HCMV) is widespread in the general population, and both molecular and epidemiological evidence has indicated links between HCMV and breast cancer. The HCMV protein cmvIL-10 is a potent suppressor of immune function that has also been shown to promote proliferation and migration of breast cancer cells. In this study, the impact of cmvIL-10 on tumor cell invasion through a simulated basement membrane was investigated.

RESULTS

MDA-MB-231 breast cancer cells exhibited invasion through a matrigel layer that was significantly enhanced in the presence of either purified cmvIL-10 or supernatants from HCMV-infected cells containing secreted cmvIL-10. Transcriptional profiling revealed that cmvIL-10 altered expression of several genes implicated in metastasis. Exposure to cmvIL-10 resulted in higher MMP-3 mRNA levels, greater protein expression, and increased enzymatic activity. Treatment with cmvIL-10 also increased expression of both urokinase plasminogen receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1), which can stimulate MMP-3 activity and have previously been identified as poor prognostic markers in breast cancer patients. Finally, MDA-MB-231 cells treated with cmvIL-10 showed significant downregulation of metastasis suppressor 1 (MTSS1), a scaffolding protein that regulates cytoskeletal rearrangements and is frequently lost in metastatic tumors.

CONCLUSIONS

HCMV, and in particular the secreted viral cytokine, cmvIL-10, can induce cellular changes that facilitate cell migration and invasion. These findings indicate that HCMV may be associated with promoting the malignant spread of breast cancer cells and suggest that antiviral treatment may be a useful complement to chemotherapy in some patients.

A microfluidic Transwell to study chemotaxis

Chemotaxis is typically studied in vitro using commercially available products such as the Transwell® in which cells migrate through a porous membrane in response to one or more clearly defined chemotactic stimuli. Despite its widespread use, the Transwell assay suffers from being largely an endpoint assay, with built-in errors due to inconsistent pore size and human sampling. In this study, we report a microfluidic chemotactic chip that provides real-time monitoring, consistent paths for cell migration, and easy on-chip staining for quantifying migration. To compare its performance with that of a traditional Transwell chamber, we investigate the chemotactic response of MDA-MB-231 1833 metastatic breast cancer cells to epidermal growth factor (EGF). The results show that while both platforms were able to detect a chemotactic response, we observed a dose-dependent response of breast cancer cells towards EGF with low non-specific migration using the microfluidic platform, whereas we observed a dose-independent response of breast cancer cells towards EGF with high levels of non-specific migration using the commercially available Transwell.The microfluidic platform also allowed EGF-dependent chemotactic responses to be observed 24h, a substantially longer window than seen with the Transwell. Thus the performance of our microfluidic platform revealed phenomena that were not detected in the Transwell under the conditions tested.

Clinical relevance between human cytomegalovirus infection and colorectal cancer

AIM: To investigate the clinical relevance between human cytomegalovirus (HCMV) infection and colorectal cancer.

METHODS: The specific immunoglobulin G (IgG) and IgM antibodies against HCMV in sera of colorectal cancer patients (n = 60), patients with colorectal polyps (n = 60) and health controls (n = 60) were detected by chemiluminescence immunoassay. HCMV infection in colorectal cancer tissues and corresponding adjacent normal samples were determined through the detection of UL138 gene by nested PCR and in situ hybridization. The relationships between HCMV infection and clinical features of colorectal cancer were analyzed.

RESULTS: The positive rates of HCMV-IgG in the colorectal cancer group, colorectal polyps group and healthy control group were 95.0% (57/60), 98.3% (59/60), and 96.7% (58/60), respectively; the positive rates of HCMV-IgM were 5.0% (3/60), 1.7% (1/60) and 1.7% (1/60), respectively. There were no statistically significant differences in the positive rates of HCMV-IgG and HCMV-IgM among the three groups. However, there was a significant difference between colorectal cancer tissues and corresponding normal tissues in HCMV-UL138 detection. The positive rates of HCMV-UL138 were 65.6% (19/32) and 62.5% (20/32) in colorectal cancer tissues samples, and 12.5% (4/32) and 9.4% (3/32) in corresponding normal tissues as revealed by nested PCR detection and in situ hybridization, respectively. HCMV infection had no significant association with age, gender, location of mass, tumor size, histological differentiation, metastasis or Dukes stage.

CONCLUSION: HCMV infection is associated with colorectal cancer. Compared with corresponding normal epithelium, the neoplastic epithelium may be preferentially infected by the HCMV. This research suggests that HCMV infection may play a role in the occurrence and development of colorectal cancer.

Constitutive activation of STAT3 in breast cancer cells: A review

Signal transducer and activator of transcription 3 (STAT3) is constitutively activated in numerous cancer types, including more than 40% of breast cancers. In contrast to tight regulation of STAT3 as a latent transcription factor in normal cells, its signaling in breast cancer oncogenesis is multifaceted. Signaling through the IL-6/JAK/STAT3 pathway initiated by the binding of IL-6 family of cytokines (i.e., IL-6 and IL-11) to their receptors have been implicated in breast cancer development. Receptors with intrinsic kinase activity such as EGFR and VEGFR directly or indirectly induce STAT3 activation in various breast cancer types. Aberrant STAT3 signaling promotes breast tumor progression through deregulation of the expression of downstream target genes which control proliferation (Bcl-2, Bcl-xL, Survivin, Cyclin D1, c-Myc and Mcl-1), angiogenesis (Hif1α and VEGF) and epithelial-mesenchymal transition (Vimentin, TWIST, MMP-9 and MMP-7). These multiple modes of STAT3 regulation therefore make it a central linking point for a multitude of signaling processes. Extensive efforts to target STAT3 activation in breast cancer had no remarkable success in the past because the highly interconnected nature of STAT3 signaling introduces lack of selectivity in pathway identification for STAT3 targeted molecular therapies or because its role in tumorigenesis may not be as critical as it was thought. This review provides a full spectrum of STAT3's involvement in breast cancer by consolidating the knowledge about its role in breast cancer development at multiple levels: its differential regulation by different receptor signaling pathways, its downstream target genes, and modification of its transcriptional activity by its coregulatory transcription factors.

Human Cytomegalovirus interleukin-10 promotes proliferation and migration of MCF-7 breast cancer cells

Breast cancer is the most common malignancy affecting women worldwide. While a small fraction of breast cancers have a hereditary component, environmental and behavioral factors also impact the development of cancer. Human cytomegalovirus (HCMV) is a member of the Herpesviridae family that is widespread in the general population and has been linked to several forms of cancer. While HCMV DNA has been found in some breast cancer tissue specimens, we wanted to investigate whether a secreted viral cytokine might have an effect on cancerous or even pre-cancerous cells. HCMV encodes an ortholog of the human cellular cytokine interleukin-10 (IL-10). The HCMV UL111A gene product is cmvIL-10, which has 27% sequence identity to IL-10 and binds the cellular IL-10 receptor (IL-10R) to induce downstream cell signaling. We found that MCF-7 human breast cancer cells express IL-10R and that exposure to cmvIL-10 results in enhanced proliferation and increased chemotaxis of MCF-7 cells. PCR arrays revealed that treatment with cmvIL-10 alters expression of cell adhesion molecules and increases MMP gene expression. In particular, MMP-10 gene expression was found to be significantly up-regulated and this correlated with an increase in cell-associated MMP-10 protein produced by MCF-7 cells exposed to cmvIL-10. These results suggest that the presence of cmvIL-10 in the tumor microenvironment could contribute to the development of more invasive tumors.

The oncogenic potential of human cytomegalovirus and breast cancer

Breast cancer is the leading causes of cancer-related death among women. The vast majority of breast cancers are carcinomas that originate from cells lining the milk-forming ducts of the mammary gland. Numerous articles indicate that breast tumors exhibit diverse phenotypes depending on their distinct physiopathological signatures, clinical courses, and therapeutic possibilities. The human cytomegalovirus (HCMV) is a multifaceted highly host specific betaherpesvirus that is regarded as asymptomatic or mildly pathogenic virus in immunocompetent host. HCMV may cause serious in utero infections as well as acute and chronic complications in immunocompromised individual. The involvement of HCMV in late inflammatory complications underscores its possible role in inflammatory diseases and cancer. HCMV targets a variety of cell types in vivo, including macrophages, epithelial cells, endothelial cells, fibroblasts, stromal cells, neuronal cells, smooth muscle cells, and hepatocytes. HCMV can be detected in the milk after delivery and thereby HCMV could spread to adjacent mammary epithelial cells. HCMV also infects macrophages and induces an atypical M1/M2 phenotype, close to the tumor-associated macrophage phenotype, which is associated with the release of cytokines involved in cancer initiation or promotion and breast cancer of poor prognosis. HCMV antigens and DNA have been detected in tissue biopsies of breast cancers and elevation in serum HCMV IgG antibody levels has been reported to precede the development of breast cancer in some women. In this review, we will discuss the potential role of HCMV in the initiation and progression of breast cancer.