IL‐6 promotes malignant growth of skin SCCs by regulating a network of autocrine and paracrine cytokines

Cytokines play a crucial role in tumor initiation and progression. Here, we demonstrate that interleukin (IL)‐6 is a key factor by driving tumor progression from benign to malignant, invasive tumors in the HaCaT‐model of human skin carcinoma. IL‐6 activates STAT3 and directly stimulates proliferation and migration of the benign noninvasive HaCaT‐ras A‐5 cells in vitro. Furthermore, IL‐6 induces a complex, reciprocally regulated cytokine network in the tumor cells that includes inflammatory and angiogenic factors such as IL‐8, GM‐CSF, VEGF and MCP‐1. These IL‐6 effects lead to tumor cell invasion in organotypic cultures in vitro and to the formation of malignant and invasive s.c. tumors in vivo. Tumor invasion is supported by the IL‐6 induced overexpression of MMP‐1 in vitro and in vivo. These data demonstrate a key function of IL‐6 in the progression of skin SCCs by regulating a complex cytokine and protease network and suggest new therapeutic approaches to target this central player in skin carcinogenesis.     

C‐reactive protein and interleukin‐6 responses for differentiating fungal and bacterial aetiology in late‐onset neonatal sepsis

Fungal infections are increasingly frequent causes of neonatal sepsis (NS). This study examined the predictive value of the combined evaluation of the C‐reactive protein (CRP) and interleukin‐6 (IL‐6) responses for differentiating fungal and bacterial aetiologies in patients with NS. From January to September 2007, neonates who were diagnosed with NS and had their CRP and IL‐6 levels measured were selected. Based on their blood culture results, the neonates were divided into two groups: group of fungal sepsis (FS) and group of bacterial sepsis (BS). FS included 14 Candida albicans and one non‐albicans Candida isolates and BS included five Klebsiella pneumoniae, three Pseudomonas aeruginosa, three Enterococcus faecalis, two coagulase‐negative Staphylococcus species, one Enterococcus faecium and one Acinetobacter species. Significant differences were observed in the CRP (FS vs. BS: 28.10 ± 11.03 vs. 11.39 ± 2.94 mg l^?1, P = 0.026) and IL‐6 (FS vs. BS: 38.60 ± 24.24 vs. 392.82 ± 102.46 ng l^?1, P = 0.000) levels between groups. The combined evaluation of the CRP and IL‐6 responses better predicted the causative micro‐organism in NS.     

Circulating prediagnostic interleukin‐6 and C‐reactive protein and prostate cancer incidence and mortality

Interleukin‐6 (IL‐6) and C‐reactive protein (CRP) are elevated in prostate cancer patients, but the role of prediagnostic levels of these inflammatory mediators on prostate cancer outcomes is unclear. We undertook a large, prospective case‐control study to evaluate the relation between prediagnostic levels of IL‐6 and CRP and prostate cancer incidence and mortality. We also investigated the role of the IL‐6 (?174 G/C) polymorphism in relation to circulating levels of IL‐6 and CRP, as well as cancer risk and mortality. We used unconditional logistic regression that adjusted for matching factors to analyze prostate cancer risk. For analyses of prostate cancer mortality, we conducted survival analyses in cases. Because of the strong link between inflammatory markers and body mass index (BMI), we assessed interactions between BMI and plasma levels on prostate cancer outcomes. Neither IL‐6 nor CRP plasma levels varied significantly by IL‐6 genotype. Genotype was not associated with prostate cancer risk or survival. Though neither IL‐6 nor CRP was associated with prostate cancer incidence overall, we observed a statistically significant interaction between IL‐6 and BMI on prostate cancer incidence (p_interaction < 0.01). Increasing IL‐6 levels were positively associated with risk in healthy weight men, but inversely associated with risk in overweight men. Further, prediagnostic IL‐6 was associated with time to prostate cancer progression/death among healthy weight prostate cancer cases (p_trend = 0.02). Adjusted hazard ratios were 1.73 (95% CI: 0.86, 3.51) comparing the highest to lowest IL‐6 level. Our study suggests that IL‐6 may potentially be involved in the development or progression of prostate cancer. © 2008 Wiley‐Liss, Inc.     

CD90+ stromal cells are the major source of IL‐6, which supports cancer stem‐like cells and inflammation in colorectal cancer

IL‐6 is a pleiotropic cytokine increased in CRC and known to directly promote tumor growth. Colonic myofibroblasts/fibroblasts (CMFs or stromal cells) are CD90⁺ innate immune cells representing up to 30% of normal colonic mucosal lamina propria cells. They are expanded in CRC tumor stroma, where they also known as a cancer associated fibroblasts (CAFs). Cells of mesenchymal origin, such as normal myofibroblasts/fibroblasts, are known to secrete IL‐6; however, their contribution to the increase in IL‐6 in CRC and to tumor‐promoting inflammation is not well defined. Using in situ, ex vivo and coculture analyses we have demonstrated that the number of IL‐6 producing CMFs is increased in CRC (C‐CMFs) and they represent the major source of IL‐6 in T2‐T3 CRC tumors. Activity/expression of stem cell markers‐aldehyde dehydrogenase and LGR5‐ was significantly up‐regulated in colon cancer cells (SW480, Caco‐2 or HT29) cultured in the presence of conditioned medium from tumor isolated C‐CMFs in an IL‐6 dependent manner. C‐CMF and its derived condition medium, but not normal CMF isolated from syngeneic normal colons, induced differentiation of tumor promoting inflammatory T helper 17 cells (Th17) cell responses in an IL‐6 dependent manner. Our study suggests that CD90⁺ fibroblasts/myofibroblasts may be the major source of IL‐6 in T2‐T3 CRC tumors, which supports the stemness of tumor cells and induces an immune adaptive inflammatory response (a.k.a. Th17) favoring tumor growth. Taken together our data supports the notion that IL‐6 producing CAFs (a.k.a. C‐CMFs) may provide a useful target for treating or preventing CRCs.     

Hepatocyte growth factor induces hypoxia‐related interleukin‐8 expression in lung adenocarcinoma cells

Rapid growth of cancer cells often creates insufficient supply of oxygen and nutrients in the tumour nest. The frequent detection of hypoxia‐inducible factor (HIF) and interleukin‐8 (IL‐8) in afflicted tissues suggests that IL‐8 expression could be associated with elevated levels of HIF. Recently, we found that hypoxia also upregulated the expression of hepatocyte growth factor (HGF) in lung adenocarcinoma (LAD) cells. However, the relationship between HGF and IL‐8 has not been investigated in LAD cells. In this study, we found that HGF induced IL‐8 expression in LAD. Interestingly, hypoxia also increased the level of prostaglandin F_2α (PGF_2α), a product of dihydrodiol dehydrogenase (DDH). When expression of DDH was suppressed by siRNA, the levels of PGF_2α, HGF and IL‐8 were reduced; however, their levels returned to normal after DDH was reintroduced. These data suggest that hypoxia induces biosynthesis of PGF_2α, which then activates HGF and IL‐8 expression. The results provide a reasonable explanation of how PGF_2α, HGF and IL‐8 exert their effects on cancer cell metastasis. © 2009 Wiley‐Liss, Inc.     

Cervical cancer cell‐derived interleukin‐6 impairs CCR7‐dependent migration of MMP‐9‐expressing dendritic cells

Cervical carcinogenesis is a consequence of persistent infection with high‐risk human papillomaviruses (HPVs). Recent studies indicate that HPV‐transformed cells actively instruct their microenvironment to promote carcinogenesis. Here, we demonstrate that cervical cancer cells activate monocytes to produce their own CCL2 for further monocyte recruitment and reprogram their function during differentiation and maturation to dendritic cells (DCs). Our data show that cervical cancer cells suppress the induction of the chemokine receptor CCR7 in phenotypically mature DCs and impair their migration toward a lymph node homing chemokine, required to initiate adaptive immune responses. We confirmed the presence of CD83⁺CCR7^low DCs in cancer biopsies. The second factor essential for DC migration, matrix‐metalloproteinase MMP‐9, which also has vasculogenic and protumorigenic properties, is not suppressed but upregulated in immature as well as mature DCs. We identified interleukin‐6 (IL‐6) as a crucial cervical cancer cell‐derived mediator and nuclear factor kappaB (NF‐κB) as the central signaling pathway targeted in DCs. Anti‐IL‐6 antibodies reverted not only NF‐κB inhibition and restored CCR7‐dependent migration but also blocked MMP‐9 induction. This is the first report demonstrating the dissociation of CCR7 and MMP‐9 expression in phenotypically mature CD83⁺ DCs by cancer cells. Our results show that cervical cancer cells actively shape the local microenvironment. They induce the accumulation of myeloid cells and skew their function from immune activation to local production of protumorigenic MMP‐9. Neutralizing anti‐IL‐6 antibodies can counteract this functional dysbalance and should therefore be considered for adjuvant cervical cancer therapy.     

Lack of interleukin‐6 in the tumor microenvironment augments type‐1 immunity and increases the efficacy of cancer immunotherapy

Conquering immunosuppression in tumor microenvironments is crucial for effective cancer immunotherapy. It is well known that interleukin (IL)‐6, a pleiotropic cytokine, is produced in the tumor‐bearing state. In the present study, we investigated the precise effects of IL‐6 on antitumor immunity and the subsequent tumorigenesis in tumor‐bearing hosts. CT26 cells, a murine colon cancer cell line, were intradermally injected into wild‐type and IL‐6‐deficient mice. As a result, we found that tumor growth was decreased significantly in IL‐6‐deficient mice compared with wild‐type mice and the reduction was abrogated by depletion of CD8⁺ T cells. We further evaluated the immune status of tumor microenvironments and confirmed that mature dendritic cells, helper T cells and cytotoxic T cells were highly accumulated in tumor sites under the IL‐6‐deficient condition. In addition, higher numbers of interferon (IFN)‐γ‐producing T cells were present in the tumor tissues of IL‐6‐deficient mice compared with wild‐type mice. Surface expression levels of programmed death‐ligand 1 (PD‐L1) and MHC class I on CT26 cells were enhanced under the IL‐6‐deficient condition in vivo and by IFN‐γ stimulation in vitro. Finally, we confirmed that in vivo injection of an anti‐PD‐L1 antibody or a Toll‐like receptor 3 ligand, polyinosinic‐polycytidylic acid, effectively inhibited tumorigenesis under the IL‐6‐deficient condition. Based on these findings, we speculate that a lack of IL‐6 produced in tumor‐bearing host augments induction of antitumor effector T cells and inhibits tumorigenesis in vivo, suggesting that IL‐6 signaling may be a promising target for the development of effective cancer immunotherapies.     

FGF‐1/‐3/FGFR4 signaling in cancer‐associated fibroblasts promotes tumor progression in colon cancer through Erk and MMP‐7

Cancer‐associated fibroblasts (CAFs), as the activated fibroblasts in the tumor stroma, are important modifiers of tumour progression. In the present study, we observed that azoxymethane and dextran sodium sulfate treatments induced increasingly severe colorectal mucosal inflammation and the intratumoural accumulation of CAFs. Fibroblast growth factor (FGF)‐1 and FGF‐3 were detected in infiltrating cells, and FGFR4, the specific receptor for FGF‐1 and FGF‐3, was detected in colon cancer tissues. The phosphorylation of FGFR4 enhanced the production of metalloproteinase (MMP)‐7 and mitogen‐activated protein kinase kinase (Mek)/extracellular signal‐regulated kinase (Erk), which was accompanied by excessive vessel generation and cell proliferation. Moreover, we separated CAFs, pericarcinoma fibroblasts (PFs), and normal fibroblasts (NFs) from human colon tissue specimens to characterize the function of CAFs. We observed that CAFs secrete more FGF‐1/‐3 than NFs and PFs and promote cancer cell growth and angiogenesis through the activation of FGFR4, which is followed by the activation of Mek/Erk and the modulation of MMP‐7 expression. The administration of FGF‐1/‐3‐neutralizing antibodies or the treatment of cells with FGFR4 siRNA or the FGFR4 inhibitor PD173074 markedly suppressed colon cancer cell proliferation and neovascularization. These observations suggest a crucial role for CAFs and FGF signaling in the initiation and progression of colorectal cancer. The inhibition of the FGF signaling pathway may be a useful strategy for the treatment of colon cancer.     

MicroRNA‐143 regulates collagen type III expression in stromal fibroblasts of scirrhous type gastric cancer

Gastric cancer (GC) is one of the most common malignancies worldwide. In particular, scirrhous type GC is highly metastatic and is characterized clinically by rapid disease progression and poor prognosis. MicroRNAs (miRNAs) play crucial roles in cancer development and progression. In the present study, we identified several miRNAs that are expressed at higher levels in scirrhous type GC than in non‐scirrhous type GC by miRNA microarray analysis. Among these, microRNA‐143 (miR‐143) expression was higher in scirrhous type GC than in non‐scirrhous types of GC. In situ hybridization and quantitative RT‐PCR analysis showed that miR‐143 is expressed by stromal fibroblasts but not by cancer cells. In stromal cells, miR‐143 enhanced collagen type III expression in normal gastric fibroblasts and cancer‐associated fibroblasts through activation of transforming growth factor‐β)/SMAD signaling. Furthermore, high miR‐143 expression in GC was associated with worse cancer‐specific mortality (P = 0.0141). Multivariate analysis revealed that miR‐143 was an independent prognostic factor. Treatment of GC cell lines with 5‐aza‐2′‐deoxycytidine restored the expression of miR‐143, and precursor miR‐143 caused the inhibition of cancer cell invasion. These data suggest that miR‐143 regulates fibrosis of scirrhous type GC through induction of collagen expression in stromal fibroblasts and that miR‐143 expression serves as a prognostic marker of GC.     

Interleukin‐12 and interleukin‐2 alone or in combination against the infection in invasive pulmonary aspergillosis mouse model

Aspergillus fumigatus is an intracellular opportunistic fungus causing invasive pulmonary mycosis, characterised by hyphal invasion and destruction of pulmonary tissue. Th1 cytokines could enhance fungicidal activity. The effects from the combination of interleukin‐12 (IL‐12) and IL‐2 are rarely known in invasive pulmonary aspergillosis infection. To assess the cleaning of A. fumigatus infection in the pulmonary tissues by IL‐12 and IL‐2, interferon‐γ (IFN‐γ) was detected in the sera using ELISA, quantification of IFN‐γ mRNA using real‐time RT‐PCR and lung Colony‐forming unit was assayed by cultivation. Morphology was analysed by histopathological examination. Our results showed that IL‐12 and/or IL‐2 could enhance the IFN‐γ expression in the pulmonary tissue, reduce the colony load in the pulmonary tissue and increase the survival rate of mouse. The combination of IL‐12 and IL‐2 could assist in increasing the IFN‐γ expression in the pulmonary tissue, but neither reduce colony load in the pulmonary tissue nor increase the survival rate of mouse significantly. It was demonstrated that IL‐12 and IL‐2 were strong immunomodulatory cytokines as a prerequisite for protecting the host from infectious agents.     

Loss of protein phosphatase 6 in mouse keratinocytes enhances K‐rasG12D‐driven tumor promotion

Here, we address the function of protein phosphatase 6 (PP6) loss on K‐ras‐initiated tumorigenesis in keratinocytes. To do so, we developed tamoxifen‐inducible double mutant (K‐ras^G12D‐expressing and Ppp6c‐deficient) mice in which K‐ras^G12D expression is driven by the cytokeratin 14 (K14) promoter. Doubly‐mutant mice showed early onset tumor formation in lips, nipples, external genitalia, anus and palms, and had to be killed by 3 weeks after induction by tamoxifen, while comparably‐treated K‐ras^G12D‐expressing mice did not. H&E‐staining of lip tumors before euthanasia revealed that all were papillomas, some containing focal squamous cell carcinomas. Immunohistochemical analysis of lips of doubly‐mutant vs K‐ras^G12D mice revealed that cell proliferation and cell size increased approximately 2‐fold relative to K‐ras^G12D‐expressing mutants, and epidermal thickness of lip tissue greatly increased relative to that seen in K‐ras^G12D‐only mice. Moreover, AKT phosphorylation increased in K‐ras^G12D‐expressing/Ppp6c‐deficient cells, as did phosphorylation of the downstream effectors 4EBP1, S6 and GSK3, suggesting that protein synthesis and survival signals are enhanced in lip tissues of doubly‐mutant mice. Finally, increased numbers of K14‐positive cells were present in the suprabasal layer of doubly‐mutant mice, indicating abnormal keratinocyte differentiation, and γH2AX‐positive cells accumulated, indicating perturbed DNA repair. Taken together, Ppp6c deficiency enhances K‐ras^G12D‐dependent tumor promotion.     

Reverse of non‐small cell lung cancer drug resistance induced by cancer‐associated fibroblasts via a paracrine pathway

The tumor microenvironment orchestrates the sustained growth, metastasis and recurrence of cancer. As an indispensable component of the tumor microenvironment, cancer‐associated fibroblasts (CAF) are considered as an essential synthetic machine producing various tumor components, leading to cancer sustained stemness, drug resistance and tumor recurrence. Here, we developed a sustainable primary culture of lung cancer cells fed with lung cancer‐associated fibroblasts, resulting in enrichment and acquisition of drug resistance in cancer cells. Moreover, IGF2/AKT/Sox2/ABCB1 signaling activation in cancer cells was observed in the presence of CAF, which induces upregulation of P‐glycoprotein expression and the drug resistance of non‐small cell lung cancer cells. Our results demonstrated that CAF cells constitute a mechanism for cancer drug resistance. Thus, traditional chemotherapy combined with insulin‐like growth factor 2 (IGF2) signaling inhibitor may present an innovative therapeutic strategy for non‐small cell lung cancer therapy.     

Requisite role of vasohibin‐2 in spontaneous gastric cancer formation and accumulation of cancer‐associated fibroblasts

The vasohibin (VASH) family consists of two genes, VASH1 and VASH2. VASH1 is mainly expressed in vascular endothelial cells and suppresses angiogenesis in an autocrine manner, whereas VASH2 is mainly expressed in cancer cells and exhibits pro‐angiogenic activity. Employing adenomatous polyposis coli gene mutant mice, we recently reported on the role of Vash2 in the spontaneous formation of intestinal tumors. In this study, we used K19‐Wnt1/C2mE (Gan) mice and examined the role of Vash2 in spontaneous gastric cancer formation. Gan mice spontaneously develop gastric tumors by activation of Wnt and prostaglandin E2 signaling pathways in gastric mucosa after 30 weeks of age. Expression of Vash2 mRNA was significantly increased in gastric tumor tissues compared with normal stomach tissues. When Gan mice were crossed with the Vash2‐deficient (Vash2^LacZ/LacZ) strain, gastric cancer formation was significantly suppressed in Vash2^LacZ/LacZ Gan mice. Normal composition of gastric mucosa was partially maintained in Vash2^LacZ/LacZ Gan mice. Knockout of Vash2 caused minimal reduction of tumor angiogenesis but a significant decrease in cancer‐associated fibroblasts (CAF) in tumor stroma. DNA microarray analysis and real‐time RT‐PCR showed that mRNA levels of epiregulin (Ereg) and interleukin‐11 (Il11) were significantly downregulated in gastric tumors of Vash2^LacZ/LacZ Gan mice. Furthermore, conditioned medium of gastric cancer cells stimulated migration of and α‐smooth muscle actin expression in fibroblasts, whereas conditioned medium of VASH2 knockdown cells attenuated these effects in vitro. These results suggest that VASH2 plays an important role in gastric tumor progression via the accumulation of CAF accompanying upregulation of EREG and IL‐11 expression.     

High serum interleukin‐6 level predicts future hepatocellular carcinoma development in patients with chronic hepatitis B

Increased interleukin‐6 (IL‐6) production is implicated in the pathogenesis of hepatocellular carcinoma (HCC) in animal models. Although previous studies showed that HCC patients had higher serum IL‐6 level at the time of diagnosis, it is unclear if the cytokine contributes to the development of HCC or is just a reaction to cancer. To address this question, we performed a nested case‐control study. Consecutive chronic hepatitis B patients were recruited from 1997 to 2000 and followed till 2008. Profiling of 27 cytokines, chemokines and growth factors was performed at baseline, date of peak alanine aminotransferase (ALT) level and the last visit. Thirty‐seven patients developed HCC at a median follow‐up of 62 months (interquartile range: 41–110). Serum IL‐6 was higher in patients with HCC than controls both during peak ALT and at the last visit (both p = 0.02). Patients with IL‐6 above 7 pg/ml during peak ALT had increased risk of HCC or death (adjusted hazard ratio 3.0; 95% confidence interval 1.2, 7.8; p = 0.02). The sensitivity, specificity, positive and negative predictive values of this cutoff to predict future HCC development were 70%, 73%, 72% and 71%, respectively. Combination of IL‐6 and AFP improved the sensitivity in diagnosing HCC or predicting future HCC development. In conclusion, high serum IL‐6 level predates the development of HCC in chronic hepatitis B patients, and has moderate accuracy in predicting future cancer. This may assist clinicians in selecting high‐risk patients for HCC surveillance program. © 2009 UICC     

The antibody‐based targeted delivery of interleukin‐4 and 12 to the tumor neovasculature eradicates tumors in three mouse models of cancer

Preclinical studies with recombinant murine interleukin 4 (IL4) in models of cancer have shown potent tumor growth inhibition. However, systemic administration of human IL4 to cancer patients exhibited modest antitumor activity and considerable toxicities. To improve the therapeutic index and reduce side effects of this cytokine, we developed of a novel “immunocytokine” based on sequential fusion of murine IL4 with the antibody fragment F8 (specific to the alternatively spliced extra‐domain A of fibronectin, a marker for tumor‐angiogenesis) in diabody format. The resulting fusion protein, termed F8‐IL4, retained full antigen‐binding activity and cytokine bioactivity and was able to selectively localize on solid tumors in vivo. When used as single agent, F8‐IL4 inhibited tumor growth in three different immunocompetent murine cancer models (F9 teratocarcinoma, CT26 colon carcinoma and A20 lymphoma). Furthermore, F8‐IL4 showed synergistic effects when coadministered with immunocytokines based on IL2 and IL12. Indeed, combination therapy with an IL12‐based immunocytokine yielded complete tumor eradication, in spite of the fact that IL4 and IL12 display opposite immunological mechanisms of action in terms of their polarization of T‐cell based responses. No weight loss or any signs of toxicity were observed in treated mice, both in monotherapy and in combination, indicating a good tolerability of the immunocytokine treatment. Interestingly, mice cured from CT26 tumors acquired a durable protective antitumor immunity. Depletion experiments indicated that the antitumor activity was mediated by CD8+ T cells and by NK cells.