Presence of S100A8/Gr1-Positive Myeloid-Derived Suppressor Cells in Primary Tumors and Visceral Organs Invaded by Breast Carcinoma Cells

Cerebral cavernous malformation proteins, CCM1, CCM2 and CCM3, are decreased in metastatic lesions in a murine breast carcinoma model

Three genes are associated with cerebral cavernous malformations (CCMs): CCM1, CCM2 and CCM3. These genes participate in microvascular angiogenesis, cell-to-cell junctions, migration and apoptosis. We evaluated the expression in vivo of CCM genes in primary tumors and metastastases in a murine model of metastatic breast carcinoma. We used cell lines obtained from metastasis of 4T1, 4TLM and 4THM breast cancer to liver and heart. These cells were injected into the mammary ridge of Balb/C female mice. After 27 days, the primary tumors, liver and lung were removed and CCM proteins were assessed using immunohistochemistry and western blot analysis. CCM proteins were expressed in primary tumor tissues of all tumor-injected animals; however, no CCM protein was expressed in metastatic tumor cells that migrated into other tissues. CCM proteins still were observed in the lung and liver tissue cells. Our findings suggest that CCM proteins are present during primary tumor formation, but when these cells develop metastatic potential, they lose CCM protein expression. CCM protein expression was lost or reduced in metastatic tissues compared to the primary tumor, which indicates that CCM proteins might participate in tumorigenesis and metastasis.

CRISPR-Cas9 based knockout of S100A8 in mammary epithelial cells enhances cell proliferation and triggers oncogenic transformation via the PI3K-Akt pathway: Insights from a deep proteomic analysis

S100A8 is a calcium-binding protein with multiple functions, including being a chemoattractant for phagocytes and playing a key role in the inflammatory response. Its expression has been shown to influence epithelial-mesenchymal transition (EMT) and metastasis in colorectal cancer. However, the role of S100A8 in cell proliferation and differentiation remains unknown. In this study, we used the CRISPR-Cas9 system to knock out S100A8 in healthy mammary epithelial cells and investigated the resulting changes in proteome profiling and signaling pathways. Our results showed that S100A8 knockout led to an increase in cell proliferation and migration, reduced cell-cell adhesion, and increased apoptosis compared to wildtype cells. Proteomics data indicated that S100A8 significantly affects cell cycle progression, cell proliferation, and cell survival through the PI3K-Akt pathway. Furthermore, our findings suggest that S100A8 function is associated with Pten expression, a negative regulator of the PI3K-Akt pathway. These results indicate that S100A8 dysregulation in healthy cells can lead to altered cellular physiology and higher proliferation, similar to cancerous growth. Therefore, maintaining S100A8 expression is critical for preserving healthy cell physiology. This study provides novel insights into the role of S100A8 in cell proliferation and differentiation and its potential relevance to cancer biology. SIGNIFICANCE: The study suggests that maintaining S100A8 expression is critical for preserving healthy cell physiology, and dysregulation of S100A8 in healthy cells can lead to altered cellular physiology and higher proliferation, similar to cancerous growth. Therefore, targeting the PI3K-Akt pathway or regulating Pten expression, a negative regulator of the PI3K-Akt pathway, may be potential strategies for cancer treatment by controlling S100A8 dysregulation. Additionally, S100A8 and S100A9 have been shown to promote metastasis of breast carcinoma by forming a metastatic milieu. However, the differential expression of S100A8 in tumors and its dual effects of antitumor and protumor make the relationship between S100A8 and tumors complicated. Currently, most research focuses on the function of S100A8 as a secretory protein in the microenvironment of tumors, and its function inside healthy cells without forming dimers remains unclear. Furthermore, the study provides insight into the role of S100A8 in cell proliferation and differentiation, which may have implications for other diseases beyond cancer. The functional role of S100A8 in normal mammary epithelial cells remains completely uncertain. Therefore, the objective of this study is to investigate the function of S100A8 on proliferation in mammary epithelial cells after its deletion and to elucidate the underlying proteins involved in downstream signaling. Our findings indicate that the deletion of S100A8 leads to excessive proliferation in normal mammary epithelial cells, reduces apoptosis, and affects cell-cell adhesion molecules required for cellular communication, resulting in a cancer-like phenotype.

Breast cancer liver metastasis: Pathogenesis and clinical implications

Breast cancer is the most common malignant disease in female patients worldwide and can spread to almost every place in the human body, most frequently metastasizing to lymph nodes, bones, lungs, liver and brain. The liver is a common metastatic location for solid cancers as a whole, and it is also the third most common metastatic site for breast cancer. Breast cancer liver metastasis (BCLM) is a complex process. Although the hepatic microenvironment and liver sinusoidal structure are crucial factors for the initial arrest of breast cancer and progression within the liver, the biological basis of BCLM remains to be elucidated. Importantly, further understanding of the interaction between breast cancer cells and hepatic microenvironment in the liver metastasis of breast cancer will suggest ways for the development of effective therapy and prevention strategies for BCLM. In this review, we provide an overview of the recent advances in the understanding of the molecular mechanisms of the hepatic microenvironment in BCLM formation and discuss current systemic therapies for treating patients with BCLM as well as potential therapeutic development based on the liver microenvironment-associated signaling proteins governing BCLM.

Targeting myeloid derived suppressor cells reverts immune suppression and sensitizes BRAF-mutant papillary thyroid cancer to MAPK inhibitors

MAPK signaling inhibitor (MAPKi) therapies show limited efficacy for advanced thyroid cancers despite constitutive activation of the signaling correlates with disease recurrence and persistence. Understanding how BRAF pathway stimulates tumorigenesis could lead to new therapeutic targets. Here, through genetic and pathological approaches, we demonstrate that BRAF^V600E promotes thyroid cancer development by increasing myeloid-derived suppressor cells (MDSCs) penetrance. This BRAF^V600E-induced immune suppression involves re-activation of the developmental factor TBX3, which in turn up-regulates CXCR2 ligands in a TLR2-NFκB dependent manner, leading to MDSCs recruitment into the tumor microenvironment. CXCR2 inhibition or MDSCs repression improves MAPKi therapy effect. Clinically, high TBX3 expression correlates with BRAF^V600E mutation and increased CXCR2 ligands, along with abundant MDSCs infiltration. Thus, our study uncovers a BRAF^V600E-TBX3-CXCLs-MDSCs axis that guides patient stratification and could be targeted to improve the efficacy of MAPKi therapy in advanced thyroid cancer patients.

BRAF-V600E mutation is common in patients with papillary thyroid carcinoma (PTC) and has been associated with an aggressive phenotype. Here the authors show that the mutation supports cancer progression by reactivating the developmental factor TBX3 and promoting the recruitment of myeloid derived suppressive cells.

Olvanil activates sensory nerve fibers, increases T cell response and decreases metastasis of breast carcinoma

BACKGROUND

Inactivation of sensory neurons expressing transient receptor potential vanilloid 1 (TRPV1) enhances breast cancer metastasis. Sensory neurons have profound effects on immune response to a wide range of diseases including cancer. Hence, activation of sensory nerves using feasible approaches such as specific TRPV1 agonists may inhibit breast cancer metastasis through neuroimmune pathways. TRPV1 agonists are considered for the treatment of pain and inflammatory diseases.

METHODS

We here first determined the effects of four different TRPV1 agonists on proliferation of three different metastatic breast carcinoma cells since TRPV1 is also expressed in cancer cells. Based on the results obtained under in-vitro conditions, brain metastatic breast carcinoma cells (4TBM) implanted orthotopically into the mammary-pad of Balb-c mice followed by olvanil treatment (i.p.). Changes in tumor growth, metastasis and immune response to cancer cells were determined.

RESULTS

Olvanil dose-dependently activated sensory nerve fibers and markedly suppressed lung and liver metastasis without altering the growth of primary tumors. Olvanil (5 mg/kg) systemically increased T cell count, enhanced intra-tumoral recruitment of CD8+ T cells and increased IFN-γ response to irradiated cancer cells and Con-A. Anti-inflammatory changes such as increased IL-10 and decrease IL-6 as well as S100A8+ cells were observed following olvanil treatment.

CONCLUSIONS

Our results show that anti-metastatic effects of olvanil is mainly due to activation of neuro-immune pathways since olvanil dose used here is not high enough to directly activate immune cells. Furthermore, olvanil effectively depletes sensory neuropeptides; hence, olvanil is a good non-pungent alternative to capsaicin.

Effects of melatonin and doxorubicin on primary tumor and metastasis in breast cancer model

BACKGROUND

Melatonin exerts oncostatic effects on breast cancer via immunomodulation and anti-oxidation. Doxorubicin is an effective chemotherapeutic agent, but parallel studies also provide ample evidence of an off-target effect of Doxorubicin in breast cancer patients.

OBJECTIVE

Combinatorial use of doxorubicin and melatonin has not been comprehensively analyzed in breast cancer models. We hypothesized that the anti-oxidative, anti-proliferative and anti-inflammatory effects of melatonin could ameliorate the off-target effects of doxorubicin in breast cancer patients and enhance the anti-tumoral effects of doxorubicin. The goal of the study is to test this hypothesis in cancer cell lines and xenografted mice.

METHODS

The effects of Melatonin and doxorubicin on the cell viability were evaluated in 4T1-Brain Metastatic Tumor (4TBM). Furthermore, the effects of melatonin and doxorubicin on the primary tumors and systemic metastasis were evaluated in the xenografted mice. Lung and liver tissues were removed and metastasis analyses were performed. The levels of p65, phospho-STAT3, CD11b+, GR1+, Ki67, and cleaved caspase-3 proteins were determined with immunohistochemistry and western blot analysis. We examined the effects of melatonin and Melatonin+Doxorubicin combination therapy on 4TBM cells.

RESULTS

Our results showed that doxorubicin inhibited the proliferation of metastatic breast cancer cells while melatonin did not affect cells. Tumor growth and metastasis were markedly suppressed in melatonin alone and combination with doxorubicin. The expression of CD11b+ and GR1+ proteins which are indicators of myeloid-derived suppressor cells (MDSCs) were noted to be reduced in both primary tumor and metastatic tissues in melatonin and doxorubicin groups.

CONCLUSION

The combination of melatonin with doxorubicin reduced primary tumor growth and distant metastasis. Based on these results, melatonin is a promising candidate for combinatory use with conventional chemotherapeutics for breast cancer treatment.

Role of melatonin in TLR4-mediated inflammatory pathway in the MTPT-induced mouse model

Neuroinflammation has an essential role in various neurodegenerative diseases including Parkinson's disease (PD). Microglial activation as a result of neuroinflammation exacerbates the pathological consequences of the disease. The toxic effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes alpha-synuclein (α-synuclein) accumulation, which leads to dopaminergic neuron death in the MPTP-induced mouse model. Toll-like receptor 4 (TLR4) stimulates release of cytokine through NF-kB by activating glial cells, thus resulting in the death of dopaminergic neurons. Melatonin has the ability to cross the blood-brain barrier and protect neurons through anti-inflammatory properties. We hypothesized that melatonin could suppress TLR4-mediated neuroinflammation, decrease cytokine release due to the inflammatory response, and reduce dopaminergic neuron loss in the MPTP-induced mouse model. In the MPTP-induced mouse model, we aimed to assess the neuroinflammatory responses caused by TLR4 activation as well as the effect of melatonin on these responses. Three-month-old male C57BL/6 mice were randomly divided into five groups; Control (Group-C), Sham (Group-S), Melatonin-treated (Group-M), MPTP-injected (Group-P), and MPTP + melatonin-injected (Group-P + M). MPTP toxin (20 mg/kg) was dissolved in saline and intraperitoneally (i.p.) injected to mice for two days with 12 h intervals. The total dose per mouse was 80 mg/kg. Melatonin was administered (20 mg/kg) intraperitoneally to Group-M and Group-P + M twice a day for five days. Eight days after starting the experiment, the motor activities of mice were evaluated by locomotor activity tests. The effects on dopamine neurons in the SNPc was determined by tyrosine hydroxylase (TH) immunohistochemistry. TLR4, α-synuclein, and p65 expression was evaluated by immunostaining as well. The amount of TNF-alpha in the total brain was evaluated by western blot analysis. In our results seen that locomotor activity was lower in Group-P compared to Group-C. However, melatonin administration was improved this impairment. MPTPcaused decrease in TH immuno-expression in dopaminergic neurons in Group-P. TLR4 (p < 0.001), α-synuclein (p < 0.001), and p65 (p < 0.01) immuno-expressions were also decreased in Group-P+M compared to Group-P (using MPTP). TNF-α expression was lower in Group-C, Group-S, Group-M, and Group-P+M, when compared to Group-P (p < 0.0001) due to the absence of inflammatory response. In conclusion, our study revealed that melatonin administration reduced α-synuclein aggregation and TLR4-mediated inflammatory response in the MPTP-induced mouse model.

S100A8/A9 Molecular Complexes Promote Cancer Migration and Invasion via the p38 MAPK Pathway in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one type of malignancy associated with migration and invasion through a currently unclear mechanism. We previously discovered S100A8/A9 levels were roughly elevated in the plasma of NPC patients as the promising biomarkers. However, their expressions and underlying functions in NPC tissues are still unknown. In the present study, we analyzed 49 NPC tissues and 20 chronic pharyngitis (CP) tissues. Immunohistochemical staining was performed in different tissues and analyzed by the Mann-Whitney U test statistically. Transwell migration and invasion experiments were further performed to determine S100A8/A9 effects on NPC. Our results showed that S100A8/A9 in NPC tissues were significantly higher than those in CP tissues, closely associated with NPC clinical stages. Intriguingly, exogenous S100A8/A9 protein stimulation could dramatically enhance NPC migration and invasion abilities. In addition, p38 MAPK pathway blockade could diminish the migration and invasion of NPC cells stimulated by S100A8/A9 proteins. The downstream tumor invasion and migration associated proteins (e.g., MMP7) were also elevated in NPC tissues, consistent with S100A8/A9 overexpression. Taken together, our present findings suggest that the secreted soluble inflammatory factors S100A8/A9 might promote cancer migration and invasion via the p38 MAPK signaling pathway along with invasion/migration associated proteins overexpression in the tumor microenvironment of NPC. This may shed light on the mechanism understanding of NPC prognosis and provide more novel clues for NPC diagnosis and therapy.

Melatonin decreases metastasis, primary tumor growth and angiogenesis in a mice model of breast cancer

The goal of this study was to mechanistically analyze the effects of pre-treatment or post-treatment melatonin on the metastatic spread in a mice model. Consequently, the effects on the tumor growth, angiogenesis and metastasis were evaluated with immunohistochemical and western blot analysis. 8-10 weeks-old female BALB/c mice (n = 60, 10/group) were used. Liver metastatic cells (4TLM) from 4T1 murine breast carcinoma were previously isolated. Melatonin was administrated either before or after the injection of 4TLM cells into the mammary pad. Tumor and vehicle (%6 ethanol) injections were given to vehicle groups. Tumor group consisted of the mice injected with only 4TLM cells injected to tumor group and no intervention to control group. Necropsies were performed 27 days after injection of 4TLM. Primary tumors and metastatic tissues were removed. Furthermore, changes in lung and liver metastasis and primary tumor growth and angiogenesis were evaluated. In our study neutrophil levels were noted to be increased in peripheral blood of the tumor-bearing mice. Melatonin exerted inhibitory effects on the 4TLM-induced leukocytosis. Melatonin significantly decreased lung and liver metastasis, primary tumor growth and angiogenesis. The results demonstrated that melatonin might have a therapeutic role through reducing systemic inflammatory responses, metastasis, tumor growth and angiogenesis.

Calprotectin in Lung Diseases

Calprotectin (CLP) is a heterodimer formed by two S-100 calcium-binding cytosolic proteins, S100A8 and S100A9. It is a multifunctional protein expressed mainly by neutrophils and released extracellularly by activated or damaged cells mediating a broad range of physiological and pathological responses. It has been more than 20 years since the implication of S100A8/A9 in the inflammatory process was shown; however, the evaluation of its role in the pathogenesis of respiratory diseases or its usefulness as a biomarker for the appropriate diagnosis and prognosis of lung diseases have only gained attention in recent years. This review aimed to provide current knowledge regarding the potential role of CLP in the pathophysiology of lung diseases and describe how this knowledge is, up until now, translated into daily clinical practice. CLP is involved in numerous cellular processes in lung health and disease. In addition to its anti-microbial functions, CLP also serves as a molecule with pro- and anti-tumor properties related to cell survival and growth, angiogenesis, DNA damage response, and the remodeling of the extracellular matrix. The findings of this review potentially introduce CLP in daily clinical practice within the spectrum of respiratory diseases.

S100A8 and S100A9 Promote Apoptosis of Chronic Eosinophilic Leukemia Cells

S100A8 and S100A9 function as essential factors in inflammation and also exert antitumor or tumorigenic activity depending on the type of cancer. Chronic eosinophilic leukemia (CEL) is a rare hematological malignancy having elevated levels of eosinophils and characterized by the presence of the FIP1L1-PDGFRA fusion gene. In this study, we examined the pro-apoptotic mechanisms of S100A8 and S100A9 in FIP1L1-PDGFRα+ eosinophilic cells and hypereosinophilic patient cells. S100A8 and S100A9 induce apoptosis of the FIP1L1-PDGFRα+ EoL-1 cells via TLR4. The surface TLR4 expression increased after exposure to S100A8 and S100A9 although total TLR4 expression decreased. S100A8 and S100A9 suppressed the FIP1L1-PDGFRα-mediated signaling pathway by downregulating FIP1L1-PDGFRα mRNA and protein expression and triggered cell apoptosis by regulating caspase 9/3 pathway and Bcl family proteins. S100A8 and S100A9 also induced apoptosis of imatinib-resistant EoL-1 cells (EoL-1-IR). S100A8 and S100A9 blocked tumor progression of xenografted EoL-1 and EoL-1-IR cells in NOD-SCID mice and evoked apoptosis of eosinophils derived from hypereosinophilic syndrome as well as chronic eosinophilic leukemia. These findings may contribute to a progressive understanding of S100A8 and S100A9 in the pathogenic and therapeutic mechanism of hematological malignancy.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.

S100A8 facilitates cholangiocarcinoma metastasis via upregulation of VEGF through TLR4/NF‑κB pathway activation

A growing body of evidence indicates that S100 calcium-binding protein A8 (S100A8) is frequently overexpressed in malignant tumor tissues and regulates tumor progression; however, the role of S100A8 in cholangiocarcinoma (CCA) remains unclear. The present study demonstrated that the protein expression of S100A8 was significantly higher in pathological tissues compared with adjacent normal tissues from patients with CCA. In addition, S100A8 expression was significantly associated with differentiation, lymph node metastasis and poor prognosis in patients following surgical resection of CCA. Furthermore, both in vitro and in vivo experiments revealed that overexpression of S100A6 promoted, while S100A8 knockdown attenuated, the migration and metastasis of CCA cells. Of note, the present results indicated that S100A8 promoted the CCA tumor cell-induced migration of vascular endothelial cells. Finally, S100A8 was demonstrated to positively regulate the expression of vascular endothelial growth factor (VEGF) in CCA cells, which was mediated by activation of the Toll-like receptor 4 (TLR4)/NF-κB pathway. In conclusion, the present study demonstrated that S100A8 had an important role in facilitating CCA cell migration and metastasis via upregulation of VEGF expression by activating the TLR4/NF-κB pathway. These findings may provide a novel target for CCA treatment.