PD‐L1/p‐STAT3 promotes the progression of NSCLC cells by regulating TAM polarization

PD‐L1 is closely related to the immune escape process of tumour cells, and targeted PD‐L1 clinical immunotherapy has been implemented. However, whether PD‐L1 is involved in TAM/M2 polarization in the TME of NSCLC and its specific mechanism remain unclear. In order to clarify the specific role of PD‐L1 in NSCLC and to seek new treatments for NSCLC, we designed a series of experimental studies. After constructing the co‐culture system and conditioned medium system, the proliferation, apoptosis, metastasis, angiogenesis, EMT process and stemness of NSCLC were detected by MTT, flow cytometry, Transwell, endothelial cell tube formation and western blot assays. The results showed that αPD‐L1 reversed TAM/M2 polarization by suppressing STAT3 phosphorylation in TAM/M2, therapy inhibiting NSCLC cell migration, angiogenesis, EMT process and stemness. However, αPD‐L1 had no effect on the proliferation and apoptosis abilities of NSCLC cells. In vivo experiments showed that αPD‐L1 inhibited lung metastasis of NSCLC and reversed TAM/M2 polarization in TME. The study investigates the mechanism by which PD‐L1 regulates TAMs polarization in TME and promotes malignant progression of NSCLC, providing a new theoretical basis for PD‐L1 targeted therapy of NSCLC.     

Renal cell carcinoma-derived exosomes deliver lncARSR to induce macrophage polarization and promote tumor progression via STAT3 pathway

Tumor-derived exosomes play a pivotal role in regulating tumor progression by mediating crosstalk between tumor cells and immune cells such as macrophages within the tumor microenvironment. Macrophages can adopt two distinct polarization statuses and switch between M1 or M2 activation phenotypes in response to the different external stimuli. However, the role of tumor derived exosomes in the macrophage phenotypic switch and tumor development have not been elucidated in renal cell carcinoma (RCC). Here we found that high macrophage infiltration was associated with worse prognosis in RCC patients, therefore we propose our hypothesis that RCC derived exosomes might directly influence macrophage polarization and thus promote tumor progression. Both cell-based in vitro models and orthotopic transplantation in vivo tumor models were constructed and ELISA, flow cytometry, and macrophage functional studies were performed to investigate whether and how RCC-derived exosomes regulate macrophage polarization and tumor growth. The results found that these exosomes promote macrophage polarization, cytokine release, phagocytosis, angiogenesis, and tumor development. Further study revealed high amount of a recently discovered lncRNA called lncARSR in RCC-derived exosomes. Overexpression of lncARSR induced phenotypic and functional changes of macrophages in vitro and promoted tumor growth in vivo, while knockdown of lncARSR by siRNA disrupted the exosomes-mediated macrophage polarization. LncARSR interacts directly with miR-34/miR- 449 to increase STAT3 expression and mediate macrophage polarization in RCC cells. Together, RCC-derived exosomes facilitate the development of tumor through inducing macrophage polarization via transferring lncARSR, suggesting that RCC-derived exosomes, lncARSR and STAT3 are the potential therapeutic targets for treatment of RCC.     

CXCL12 derived from CD248-expressing cancer-associated fibroblasts mediates M2-polarized macrophages to promote nonsmall cell lung cancer progression

Nonsmall cell lung cancer (NSCLC) is among the most prevalent malignant tumours threatening human health. In the tumour microenvironment (TME), cancer-associated fibroblasts (CAFs) induce M2-polarized macrophages, which strongly regulate tumour progression. However, little is known about the association between CAFs and M2 macrophages. CD248 is a transmembrane glycoprotein found in several cancer cells, tumour stromal cells, and pericytes. Here, we isolated CAFs from tumour tissues of NSCLC patients to detect the relationship between CD248 expression and patient prognosis. We knocked down the expression of CD248 on CAFs to detect CXCL12 secretion and macrophage polarization. We then examined the effects of CD248-expressing CAF-induced M2 macrophage polarization to promote NSCLC progression in vitro and in vivo. We found that CD248 is expressed mainly in NSCLC-derived CAFs and that the expression of CD248 correlates with poor patient prognosis. Blocking CXCL12 receptor (CXCR4) drastically decreased M2 macrophage chemotaxis. CD248 promotes CAFs secreting CXCL12 to mediate M2-polarized macrophages to promote NSCLC progression both in vitro and in vivo. Collectively, our data suggest that CD248-positive CAFs induce NSCLC progression by mediating M2-polarized macrophages.     

A novel tubulin inhibitor, 6h,suppresses tumor-associated angiogenesis and shows potent antitumor activity against non–small cell lung cancers

Tumor angiogenesis is closely associated with the metastasis and progression of non–small cell lung cancer (NSCLC), a highly vascularized solid tumor. However, novel therapeutics are lacking for the treatment of this cancer. Here, we developed a series of 2-aryl-4-(3,4,5-trimethoxy-benzoyl)-5-substituted-1,2,3-triazol analogs (6a–6x) as tubulin colchicine-binding site inhibitors, aiming to find a novel promising drug candidate for NSCLC treatment. We first identified 2-(2-fluorophenyl)-3-(3,4,5-trimethoxybenzoyl)-5-(3-hydroxyazetidin-1-yl)-2H-1,2,3-triazole (6h) as a hit compound, which inhibited angiogenesis induced by NSCLC cells both in vivo and in vitro. In addition, our data showed that 6h could tightly bind to the colchicine-binding site of tubulin and inhibit tubulin polymerization. We also found that 6h could effectively induce G2/M cell cycle arrest of A549 and H460 cells, inhibit cell proliferation, and induce apoptosis. Furthermore, we showed 6h had the potential to inhibit the migration and invasion of NSCLC cells, two basic characteristics of tumor metastasis. Finally, we found 6h could effectively inhibit tumor progression in A549 xenograft mouse models with minimal toxicity. Taken together, these findings provide strong evidence for the development of 6h as a promising microtubule colchicine-binding site inhibitor for NSCLC treatment.     

可利霉素通过调控巨噬细胞极化影响黑色素瘤的增殖*

To investigate whether carrimycin (CAM) affects the occurrence and development of melanoma by regulating the polarization of macrophages, and the following related cell biology assays were used to examine its function. Methods: The effect of CAM on macrophage polarization was detected by real-time quantitative polymerase chain reaction (Q-RT-PCR) and Western blot. Flow cytometry and Cell Counting Kit-8 were used to detect the effect of CAM on mouse macrophages in vitro and in vivo phagocytosis and proliferation. Cell line-derived xenograft model was constructed via B16-F10 to evaluate the anti-tumor effect of CAM on melanoma. Results: In the mRNA level, CAM could up-regulate the levels of TNF-α and iNOS in M1 and down-regulate the level of Arg-1 in M2. In the protein level, CAM can increase the expression of p-STAT1 and decrease the expression of p-STAT3. In the cell line-derived xenograft model, these data shown that the occurrence and CAM development of melanoma was inhibited after CAM treatment, the tumor inhibition rate was 41.6%, and promoted the increase of the number of M1 macrophages (P<0.05). Conclusion: CAM promotes the increase in the number of M1 macrophages in vivo and inhibits the progression of melanoma, suggesting that CAM may achieve anti-tumor effects by inducing the polarization of macrophages to M1.     

The effects and mechanisms of SLC34A2 in tumorigenesis and progression of human non-small cell lung cancer

Background

SLC34A2 with highest expressions in lung, small intestine and kidney encoded a type 2b sodium-dependent phosphate transporter (NaPi-IIb). In lung, SLC34A2 only expressed in the apical membrane of type II alveolar epithelium cells (ATII cells) and played a pivotal role during the fetal lung development and embryonic development. ATII cells acting as multifunctional stem cells might transform into NSCLC after undergoing exogenous or endogenous factors. Increasing evidences showed that the genes performing critical roles during embryogenesis were also expressed during the development of cancer. In addition, recent research found the expression of SLC34A2 had a significant difference between the surgical samples of NSCLC and normal tissues, and SLC34A2 was down-regulated in lung adenocarcinoma cell line A549 and up-regulation expression of SLC34A2 could significantly inhibit cell viability and invasion of A549 in vitro. These results suggested SLC34A2 might play an important role in the development of NSCLC. However, the role of SLC34A2 in tumorigenesis and progression of NSCLC remains unknown.

Results

Our study found that SLC34A2 was also significantly down-regulated in 14/15 of examined NSCLC tissues. Moreover, we found that expressions of SLC34A2 were reduced in six NSCLC cell lines for the first time. Our result also revealed a dramatic inhibitory effects of SLC34A2 on cell growth, migration and invasion of several NSCLC cell lines. SLC34A2 also strongly inhibited tumor growth and metastasis ability in A549 subcutaneous tumor model and lung metastasis model, respectively. Further studies found that the suppressive effects of SLC34A2 on tumorigenesis and progression might be associated with the down-regulation of related protein in PI3K/Akt and Ras/Raf/MEK signal pathway.

Conclusions

For the first time, our data indicated that SLC34A2 could exert significantly suppressive effects on tumorigenesis and progression of NSCLC. SLC34A2 might provide new insights for further understanding the early pathogenesis of human NSCLC.     

Doxycycline Inhibits Polarization of Macrophages to the Proangiogenic M2-type and Subsequent Neovascularization

Macrophages occur along a continuum of functional states between M1-type polarized macrophages with antiangiogenic and antitumor activity and M2-type polarized macrophages, which have been implicated to promote angiogenesis and tumor growth. Proangiogenic M2-type macrophages promote various pathologic conditions, including choroidal neovascularization in models of neovascular age-related macular degeneration, or certain cancers, such as glioblastoma multiforme. Thus, a potential novel therapeutic approach to target pathological angiogenesis in these conditions would be to inhibit the polarization of macrophages toward the proangiogenic M2-type. However, no pharmacological inhibitors of M2-type macrophage polarization have been identified yet. Here we performed an unbiased pharmacological and small chemical screen to identify drugs that inhibit proangiogenic M2-type macrophage polarization and block pathologic macrophage-driven neovascularization. We identified the well tolerated and commonly used antibiotic doxycycline as a potent inhibitor of M2-type polarization of macrophages. Doxycycline inhibited, in a dose-dependent manner, M2-type polarization of human and bone marrow-derived mouse macrophages without affecting cell viability. Furthermore, doxycycline inhibited M2-type macrophage polarization and subsequent neovascularization in vivo in a laser injury model of choroidal neovascularization. Thus, doxycycline could be used to enhance current antiangiogenic treatment approaches in various conditions that are promoted by proangiogenic M2-type macrophages, including neovascular age-related macular degeneration and certain cancers.     

β-Carotene exerts anti-colon cancer effects by regulating M2 macrophages and activated fibroblasts

The tumor microenvironment (TME), consisting of stromal fibroblasts, immune cells, cancer cells and other cell types, plays a crucial role in cancer progression and metastasis. M2 macrophages and activated fibroblasts (AFs) modulate behavior of cancer cells in the TME. Since nutritional effects on cancer progression, including colorectal cancer (CRC), may be mediated by alterations in the TME, we determined the ability of β-carotene (BC) to mediate anti-cancer effects through regulation of macrophage polarization and fibroblast activation in CRC. The M2 macrophage phenotype was induced by treating U937 cells with phorbol-12-myristate-13-acetate and interleukin (IL)-4. Treatment of these M2 macrophages with BC led to suppression of M2-type macrophage-associated markers and of the IL-6/STAT3 signaling pathway. In separate experiments, AFs were induced by treating CCD-18Co cells with transforming growth factor-β1. BC treatment suppressed expression of fibroblast activation markers. In addition, conditioned media from BC-treated M2 macrophages and AF inhibited cancer stem cell markers, colon cancer cell invasiveness and migration, and the epithelial-mesenchymal transition (EMT). In vivo, BC supplementation inhibited tumor formation and the expression of M2 macrophage markers in an azoxymethane/dextran sodium sulfate-induced colitis-associated CRC mouse model. To our knowledge, the present findings provide the first evidence suggesting that the potential therapeutic effects of BC on CRC are mediated by the inhibition of M2 macrophage polarization and fibroblast activation.     

血小板反应蛋白4通过诱导肿瘤相关巨噬细胞M2型极化促进肝癌细胞转移

血小板反应蛋白4 (thrombospondin 4, THBS4)属于THBS家族成员,是细胞外基质分泌的蛋白质,参与调控细胞增殖、黏附及血管生成等多种生理过程。近来研究表明,机体在炎症刺激下加速产生THBS4并诱导巨噬细胞粘附与积累。我们的前期研究证实,THBS4在肝癌(hepatocellular carcinoma, HCC)中发挥促癌作用,但THBS4对肝癌免疫微环境的影响尚不明确。本文旨在分析THBS4通过诱导肿瘤相关巨噬细胞M2型极化,促进肝癌细胞转移的作用。通过肝癌条件培养基(HCC conditioned medium, HCM)模拟肿瘤微环境,发现在HCM作用下巨噬细胞中THBS4表达呈时间依赖性升高(P<0.05);下调THBS4促使M1型巨噬细胞标志物IL-1β、CD86的表达升高(P<0.01),而M2型标志物IL-10和CD206表达降低(P<0.01)。进一步通过Transwell共培养实验检测THBS4诱导的M2型巨噬细胞对肝癌转移的影响。将下调THBS4的M2型巨噬细胞(M2-TAMs)与HepG2肝癌细胞进行共培养。结果显示,下调T...     

Tumor-derived lactate induces M2 macrophage polarization via the activation of the ERK/STAT3 signaling pathway in breast cancer

Tumor-associated macrophages (TAM) are prominent components of tumor microenvironment (TME) and capable of promoting cancer progression. However, the mechanisms for the formation of M2-like TAMs remain enigmatic. Here, we show that lactate is a pivotal oncometabolite in the TME that drives macrophage M2-polarization to promote breast cancer proliferation, migration, and angiogenesis. In addition, we identified that the activation of ERK/STAT3, major signaling molecules in the lactate signaling pathway, deepens our molecular understanding of how lactate educates TAMs. Moreover, suppression of ERK/STAT3 signaling diminished tumor growth and angiogenesis by abolishing lactate-induced M2 macrophage polarization. Finally, research data of the natural compound withanolide D provide evidence for ERK/STAT3 signaling as a potential therapeutic strategy for the prevention and treatment of breast cancer. These findings suggest that the lactate-ERK/STAT3 signaling pathway is a driver of breast cancer progression by stimulating macrophage M2-like polarization and reveal potential new therapeutic targets for breast cancer treatment.     

Clinical and biological significance of Cdk10 in hepatocellular carcinoma

Cyclin-dependent kinase 10 (Cdk10) is a Cdc2-related kinase and plays an essential role in the progression from the G2 to M phase of the cell cycle. However, relative little is known about its expression pattern, clinical relevance, and biological function in hepatocellular carcinoma (HCC). In the present study, we investigated the mRNA and protein expression levels of Cdk10 in 127 pairs of HCC samples and adjacent nontumorous liver tissues and evaluated its clinical significance. Additionally, we assessed the effects of restoration of Cdk10 on cell proliferation and drug sensitivity in HCC cells. We showed that the Cdk10 mRNA and protein expression was markedly decreased in HCC samples compared to adjacent nontumorous liver tissues. Quantitative real-time polymerase chain reaction and immunohistochemical studies revealed that reduced Cdk10 expression was significantly associated with alpha-fetoprotein levels, tumor size, and tumor stage. Ectopic expression of Cdk10 reduced HCC cell proliferation, blocked the cell cycle at the G0-G1 phase, as well as inhibited cell migration and anchorage-independent growth. Additionally, Cdk10 overexpression enhanced the chemosensitivity of HCC cells to cisplatin and epidoxorubicin, two chemotherapeutic agents commonly used in HCC. These data collectively demonstrate that reduced Cdk10 expression is closely linked to HCC development and progression. Restoration of its expression may have therapeutic benefits in treating this malignancy.     

LncRNA DGUOK-AS1 facilitates non-small cell lung cancer growth and metastasis through increasing TRPM7 stability via m6A modification

BackgroundN6-methyladenosine (m6A) modification plays key roles in tumor progression. LncRNA deoxyguanosine kinase antisense RNA 1 (DGUOK-AS1) has been reported as a promoter in tumors, but its role and mechanism in non-small cell lung cancer (NSCLC) development remain uncertain.MethodsCell proliferation, migration, invasion and angiogenesis were investigated via CCK-8, colony formation, transwell, and tube formation assays, respectively. The location of DGUOK-AS1 was detected via FISH assay. The interaction relationship among DGUOK-AS1, IGF2BP2 and TRPM7 was confirmed by RIP and MeRIP assays. The effects of DGUOK-AS1 on NSCLC growth and metastasis in vivo were investigated using xenograft and pulmonary metastatic models.ResultsDGUOK-AS1 was upregulated in NSCLC. DGUOK-AS1 silencing inhibited NSCLC cell proliferation, migration, invasion and angiogenesis. DGUOK-AS1 was mostly expressed in cytoplasm, and positively regulated IGF2BP2. METTL3/IGF2BP2 axis could increase TRPM7 mRNA stability in m6A-dependent manner. TRPM7 overexpression reversed the inhibitive function of DGUOK-AS1 silencing on NSCLC development. DGUOK-AS1 knockdown suppressed NSCLC cell growth and metastasis in nude mice.ConclusionDGUOK-AS1 silencing restrains NSCLC cell growth and metastasis through decreasing TRPM7 stability via regulation of the METTL3/IGF2BP2-mediated m6A modification.     

Critical role of VCP/p97 in the pathogenesis and progression of non-small cell lung carcinoma

Background

Valosin-containing protein (VCP)/p97 is an AAA ATPase molecular chaperone that regulates vital cellular functions and protein-processing. A recent study indicated that VCP expression levels are correlated with prognosis and progression of non-small cell lung carcinoma (NSCLC). We not only verified these findings but also identified the specific role of VCP in NSCLC pathogenesis and progression.

Methodology/Principal Findings

Our results show that VCP is significantly overexpressed in non-small cell lung carcinoma (NSCLC) as compared to normal tissues and cell lines (p<0.001). Moreover, we observed the corresponding accumulation of ubiquitinated-proteins in NSCLC cell lines and tissues as compared to the normal controls. VCP inhibition by si/shRNA or small-molecule (Eeyarestatin I, EerI) significantly (p<0.05, p<0.00007) suppressed H1299 proliferation and migration but induced (p<0.00001) apoptosis. Cell cycle analysis by flow cytometry verified this data and shows that VCP inhibition significantly (p<0.001, p<0.003) induced cell cycle arrest in the G0/G1 phases. We also found that VCP directly regulates p53 and NFκB protein levels as a potential mechanism to control tumor cell proliferation and progression. Finally, we evaluated the therapeutic potential of VCP inhibition and observed significantly reduced NSCLC tumor growth in both in vitro and xenograft murine (athymic-nude) models after EerI treatment (p<0.05).

Conclusions/Significance

Thus, targeting VCP in NSCLC may provide a novel strategy to restore p53 and NFκB levels and ameliorate the growth and tumorigenicity, leading to improved clinical outcomes.     

NEK2 enhances malignancies of glioblastoma via NIK/NF-κB pathway

Glioblastoma (GBM) is one of the most lethal primary brain tumor with a poor median survival less than 15 months. Despite the development of the clinical strategies over the decades, the outcomes for GBM patients remain dismal due to the strong proliferation and invasion ability and the acquired resistance to radiotherapy and chemotherapy. Therefore, developing new biomarkers and therapeutic strategies targeting GBM is in urgent need. In this study, gene expression datasets and relevant clinical information were extracted from public cancers/glioma datasets, including TCGA, GRAVENDEEL, REMBRANDT, and GILL datasets. Differentially expressed genes were analyzed and NEK2 was picked as a candidate gene for subsequent validation. Human tissue samples and corresponding data were collected from our center and detected by immunohistochemistry analysis. Molecular biological assays and in vivo xenograft transplantation were performed to confirm the bioinformatic findings. High-throughput RNA sequencing, followed by KEGG analysis, GSEA analysis and GO analysis were conducted to identify potential signaling pathways related to NEK2 expression. Subsequent mechanism assays were used to verify the relationship between NEK2 and NF-κB signaling. Overall, we identified that NEK2 is significantly upregulated in GBM and the higher expression of NEK2 exhibited a poorer prognosis. Functionally, NEK2 knockdown attenuated cell proliferation, migration, invasion, and tumorigenesis of GBM while NEK2 overexpression promoted the GBM progression. Furthermore, High-throughput RNA sequencing and bioinformatics analysis indicated that NEK2 was positively related to the NF-κB signaling pathway in GBM. Mechanically, NEK2 activated the noncanonical NF-κB signaling pathway by phosphorylating NIK and increasing the activity and stability of NIK. In conclusion, NEK2 promoted the progression of GBM through activation of noncanonical NF-κB signaling, indicating that NEK2- NF-κB axis could be a potential drug target for GBM.Subject terms: CNS cancer, Nuclear receptors     

CircABCB10 promotes nonsmall cell lung cancer cell proliferation and migration by regulating the miR-1252/FOXR2 axis

Circular RNA (circRNA) is a key regulator in the development and progression of human cancers. Previous studies confirmed circRNA-0008717 (circABCB10) as an oncogene in osteosarcoma, but the regulatory effect of circABCB10 in nonsmall cell lung cancer (NSCLC) is still unclear. In the current study, we examined the expression of circABCB10 in different NSCLC cell lines. Bioinformatics analysis, Cell Counting Kit-8 assays, Transwell migration, fluorescein reporting experiments, and xenografts in mice were used to detect the effect of circABCB10 on NSCLC cell proliferation and migration in vitro and tumor growth in vivo. The results showed that the expression of circABCB10 in NSCLC cell lines was increased. Downregulation of circABCB10 suppressed NSCLC cell proliferation and migration by promoting microRNA miR-1252 expression and suppressing Forkhead box 2 (FOXR2). Fluorescein reporting experiments confirmed that circABCB10 expression increased FOXR2 levels by sponging miR-1252, and in vivo experiments found that knockdown of circABCB10 decreased tumor growth. These data suggested that circABCB10 acted as a tumor promoter through a novel miR-1252/FOXR2 axis, providing potential biomarkers and therapeutic targets for the management of NSCLC.     

The mechanism of lncRNA-CRNDE in regulating tumour-associated macrophage M2 polarization and promoting tumour angiogenesis

M2 macrophages can promote liver cancer metastasis by promoting tumour angiogenesis; however, the mechanism underlying macrophage polarization has not been completely revealed. In this study, we mainly explored the mechanism underlying long non-coding RNA-CRNDE (lncRNA-CRNDE) in regulating M2 macrophage polarization and promoting liver cancer angiogenesis. The expression of CRNDE was up-regulated or down-regulated in THP-1 cells (CRNDE^-/--THP-1 cells and pcDNA3.1-CRNDE-THP-1). THP-1 cells were co-cultured with liver cancer cell line H22, and M2 polarization was induced in THP-1 by IL-4/13 to simulate tumour-induced macrophage polarization. As a result, after CRNDE overexpression, THP-1 cell viability was up-regulated, the expression of M2 membrane marker CD163 was up-regulated, and the proportion of F4/80 + CD163+ cells was also up-regulated. ELISA assay showed that the expression of M2 markers (including TGF-β1 and IL-10) and chemokines (including CCl22 and CCL22) was up-regulated, and the expression of key signals (including STAT6, JAK-1, p-AKT1, and Arg-1) was also up-regulated, which were significantly different compared with the control group (Con). In addition, the intervention effect of CRNDE on THP-1 was consistent between co-culture with H22 cells and IL-4/13 induction assay. The induced M2 THP-1 cells were co-cultured with HUVEC. As a result, THP-1 cells with CRNDE overexpression can promote the migration and angiogenesis of HUVEC cells in vitro and simultaneously up-regulate the expression of Notch1, Dll4 and VEGFR2, indicating that THP-1 M2 polarization induced by CRNDE could further promote angiogenesis. The H22 cell tumour-bearing mouse model was constructed, followed by injection of CRNDE anti-oligosense nucleotides and overexpression plasmids to interfere CRNDE expression in tumour-bearing tissues. Consequently, down-regulation of CRNDE could down-regulate tumour volume, simultaneously down-regulate the expression of CD163 and CD31 in tissues, decrease the expression of key proteins (including JAK-1, STAT-6, p-STAT6 and p-AKT1), and down-regulate the expression of key angiogenesis-related proteins (including VEGF, Notch1, Dll4 and VEGFR2). In this study, we found that CENDE could indirectly regulate tumour angiogenesis by promoting M2 polarization of macrophages, which is also one of the mechanisms of microenvironmental immune regulation in liver cancer.     

Absent in melanoma 2-mediating M1 macrophages facilitate tumor rejection in renal carcinoma

Absent in melanoma 2 (AIM2) as an immune regulator for the regulation of tumor-associated macrophages (TAMs) function is unclear in tumor development. Here, the AIM2 function was investigated in TAMs-mediated malignant behaviors of renal carcinoma. The correlation analysis result showed that the AIM2 expression in TAMs was negatively correlated with the percentages of M2-like polarization phenotype in human or murine renal cancer specimens. By the cocultured assay with bone marrow-derived macrophages (BMDMs) and Renca cells, overexpression of AIM2 in macrophages enhanced the inflammasome activation and reversed the phenotype from M2 to M1. Compared with BMDMs-Ctrl cocultured group, BMDMs-AIM2 cocultured group showed reduced tumor cell proliferation and migration. The blockade of inflammasome activation by the inhibitor Ac-YVAD-CMK abrogated AIM2-mediated M1 polarization and the inhibition of tumor cell growth. To evaluate the therapeutic efficacy of AIM2-mediated M1 macrophages in vivo, BMDMs-AIM2 were intravenously injected into subcutaneous Renca-tumor mice. The results showed that the infiltration of M1 TAMs was increased and tumor growth was suppressed in BMDMs-AIM2-treated mice when compared with BMDMs-Ctrl-treat mice. Accordingly, the blockade of inflammasome activation reduced the anti-tumor activities of BMDMs-AIM2. Moreover, the lung metastases of renal carcinoma were suppressed by the administration of BMDMs-AIM2 accompanied with the reduced tumor foci. These results demonstrated that AIM2 enhanced TAMs polarization switch from anti-inflammatory M2 phenotypy to pro-inflammatory M1 through inflammasome signaling activation, thus exerting therapeutic intervention in renal carcinoma models. Our results provide a possible molecular mechanism for the modulation of TAMs polarization in tumor microenvironment and open a new potential therapeutic approach for renal cancer.     

Tumor-Produced Versican V1 Enhances hCAP18/LL-37 Expression in Macrophages through Activation of TLR2 and Vitamin D3 Signaling to Promote Ovarian Cancer Progression In Vitro

Tumor-associated macrophages have been shown to promote tumor growth. They may have an obligatory function in angiogenesis, invasion, and metastasis through release of inflammatory mediators. Their presence in ovarian cancer has been correlated with poor prognosis in these patients. The human cationic antimicrobial protein-18 (hCAP18)/LL-37 was originally identified as an effector molecule of the innate immune system. It is released by innate immune cells, such as macrophages, to combat microorganisms. Previous studies have characterized the hCAP18/LL-37 as a growth factor that has been shown to promote ovarian tumor progression. However, the role hCAP18/LL-37 has in macrophage-promoted ovarian tumor development and how its expression is controlled in this context remains poorly understood. Here, we demonstrate in co-culture experiments of macrophages and ovarian cancer cells a significant increase in the in vitro proliferation and invasiveness of the tumor cells is observed. These enhanced growth and invasion properties correlated with hCAP18/LL-37 induction. HCAP18/LL-37 expression was diminished by addition of two neutralizing antibodies, TLR2 or TLR6, as well as Cyp27B1 or VDR inhibitors. Furthermore, either the TLR2 or TLR6 antibody reduced vitamin D3 signaling and tumor cell progression in vitro. Addition of Cyp27B1 or VDR inhibitors abrogated TLR2/6 activation-induced expression of hCAP18/LL-37 in macrophages. Knockdown of tumor-produced versican V1 by RNAi in these tumor cells led to a decreased induction of hCAP18/LL-37 in macrophages. Versican V1 knockdown also inhibited TLR2 and vitamin D3 signaling, as well as growth and invasiveness of these tumor cells in the in vitro co-culture. In summary, we have found that versican V1 enhances hCAP18/LL-37 expression in macrophages through activation of TLR2 and subsequent vitamin D-dependent mechanisms which promote ovarian tumor progression in vitro.