Growth stimulation of non-small cell lung cancer xenografts by granulocyte-macrophage colony-stimulating factor (GM-CSF)

Construction of a Two-Gene Immunogenomic-Related Prognostic Signature in Lung Squamous Cell Carcinoma

Lung cancer has the highest tumor incidence in China. Lung squamous cell carcinoma (LUSC) is the most common type, accounting for 40–51% of primary lung cancers. LUSC is slow in growth and late in metastasis. Immune-related genes (IRGs) and immune infiltrating cells play a vital role in the clinical outcomes of LUSC. It is important to systematically study its immune gene map to help the prognosis of cancer patients. In this study, we combined the prognostic landscape and expression status of IRGs downloaded from the TCGA and InnatedDB databases and systematically analyzed the prognostic information of LUSC patients to obtain IRGs. After systematically exploring the survival analysis, prognosis-related genes were found, and the PPI network revealed that a total of 11 genes were hub genes. A two-gene prognosis risk model was established by multivariate Cox analysis. Two IRGs were closely correlated with the prognosis of LUSC. Based on these two genes, a new independent prognostic risk model was established, and this model was further verified in the GEO database. Moreover, the risk score of the model was correlated with sex, survival status, and lymphatic metastasis in LUSC patients, and the predictive risk of the prognostic risk model was significantly positively correlated with five kinds of immune cells (CD4 T cells, CD8 T cells, neutrophils, macrophages, and dendritic cells). This study comprehensively analyzed immunogenomics and presented immune-related prognostic biomarkers for LUSC.

Myeloid-derived suppressor cells promote epithelial ovarian cancer cell stemness by inducing the CSF2/p-STAT3 signalling pathway

Myeloid‐derived suppressor cells (MDSCs) are known to contribute to tumour immune evasion, and studies have verified that MDSCs can induce cancer stem cells (CSCs) and promote tumour immune evasion in breast cancers, cervical cancers and glioblastoma. However, the potential function of MDSCs in regulating CSCs in epithelial ovarian cancer (EOC) progression is unknown. Our results indicated that compared to nonmalignant ovarian patients, EOC patients showed a significantly increased proportion of MDSCs in the peripheral blood. In addition, MDSCs dramatically promoted tumour sphere formation, cell colony formation and CSC accumulation, and MDSCs enhanced the expression of the stemness biomarkers NANOG and c‐MYC in EOC cells during coculture. Moreover, the mechanisms by which MDSCs enhance EOC stemness were further explored, and 586 differentially expressed genes were found in EOC cells cocultured with or without MDSCs; during coculture, the expression level of colony‐stimulating factor 2 (CSF2) was significantly increased in EOC cells cocultured with MDSCs. Furthermore, the depletion of CSF2 in EOC cells was successfully performed, the promotive effects of MDSCs on EOC cell stemness could be markedly reversed by downregulating CSF2 expression, p‐STAT3 signalling pathway molecules were also altered, and the p‐STAT3 inhibitor could markedly reverse the promotive effects of MDSCs on EOC cell stemness. In addition, the CSF2 expression level was correlated with EOC clinical staging. Therefore, MDSCs enhance the stemness of EOC cells by inducing the CSF2/p‐STAT3 signalling pathway. Targeting MDSCs or CSF2 may be a reasonable strategy for enhancing the efficacy of conventional treatments.

Database

Gene expression data files are available in the GEO databases under the accession number(s) GSE145374.

Validation of Neutrophil Count as An Algorithm-Based Predictive Factor of Progression-Free Survival in Patients with Metastatic Soft Tissue Sarcomas Treated with Trabectedin

Introduction: Based on a mathematical model of trabectedin-induced neutropenia, we assessed the predictive value of absolute neutrophil count (ANC) on progression-free survival (PFS) in an independent validation cohort of patients treated with trabectedin. Methods: We collected data from 87 patients in two expert centers who received at least two cycles of trabectedin for soft tissue sarcomas (STS) treatment. Correlations between ANC, patients' characteristics, and survival were assessed, and a multivariate model including tumor grade, performance status, ANC, and hemoglobin level was developed. Results: Therapeutic ANC ≥ 7.5 G/L level was associated with shorter PFS: 3.22 months (95% confidence interval (CI), 1.57⁻4.87) in patients with ANC ≥ 7.5 G/L vs. 5.78 months (95% CI, 3.95⁻7.61) in patients with ANC < 7.5 G/L (p = 0.009). Age, primary localization, lung metastases, dose reduction, hemoglobin, and albumin rates were also associated with PFS. In multivariate analysis, ANC ≥ 7.5 G/L was independently associated with poor PFS and overall survival. Conclusion: We validated increased pre-therapeutic ANC as a predictive factor of short PFS in patients starting trabectedin for STS. ANC appears to have an impact on survival rates and may be used as a decision-making tool for personalizing second-line strategies in patients with metastatic STS.

STAT3 activation confers trastuzumab-emtansine (T-DM1) resistance in HER2-positive breast cancer

Trastuzumab‐emtansine (T‐DM1) is an antibody‐drug conjugate that has been approved for the treatment of human epidermal growth factor receptor 2 (HER2)‐positive metastatic breast cancer. Despite the remarkable efficacy of T‐DM1 in many patients, resistance to this therapeutic has emerged as a significant clinical problem. In the current study, we used BT‐474/KR cells, a T‐DM1‐resistant cell line established from HER2‐positive BT‐474 breast cancer cells, as a model to investigate mechanisms of T‐DM1 resistance and explore effective therapeutic regimens. We show here for the first time that activation of signal transducer and activator of transcription 3 (STAT3) mediated by leukemia inhibitory factor receptor (LIFR) overexpression confers resistance to T‐DM1. Moreover, secreted factors induced by activated STAT3 in resistant cells limit the responsiveness of cells that were originally sensitive to T‐DM1. Importantly, STAT3 inhibition sensitizes resistant cells to T‐DM1, both in vitro and in vivo, suggesting that the combination T‐DM1 with STAT3‐targeted therapy is a potential treatment for T‐DM1‐refractory patients.

Prognostic significance of preoperative aspartate aminotransferase to neutrophil ratio index in patients with hepatocellular carcinoma after hepatic resection

Objectives

Various inflammation-based prognostic scores have been associated with poor survival in patients with hepatocellular carcinoma (HCC), and neutrophils display important roles. However, few studies have illuminated the relationship between preoperative aspartate aminotransferase (AST) to neutrophil ratio index (ANRI) and poor prognosis of HCC. We aimed to clarify the prognostic value of ANRI and evaluate the ability of different inflammation-based prognostic scores such as ANRI, AST to lymphocyte ratio index (ALRI), AST to platelet count ratio index (APRI), neutrophil-lymphocyte ratio index (NLR), and platelet-lymphocyte ratio index (PLR).

Methods

Data were collected retrospectively from 303 patients who underwent curative resection for HCC. Preoperative ANRI, ALRI, APRI, NLR, PLR and clinico-pathological variables were analyzed. Univariate, multivariate and Kaplan-Meier analyses were performed to identify the predictive value of the above factors for disease-free survival (DFS) and overall survival (OS).

Results

ANRI was correlated with presence of HBsAg, AST, presence of cirrhosis, tumor size, PVTT, cancer of the liver Italian program (CLIP) score, recurrence. Univariate analysis showed ANRI, ALRI, APRI, NLR, PLR were significantly associated with DFS and OS in HCC patients with curative resection. After multivariate analysis, ANRI was demonstrated to be superior to ALRI, APRI, NLR, PLR, which were independently correlated with DFS and OS. Survival analysis showed that preoperative ANRI > 7.8 predicted poor prognosis of patients with HCC after hepatectomy. preoperative ANRI also showed different prognostic value in various subgroups of HCC. Furthermore, the predictive range was expanded by the combination of ANRI and NLR.

Conclusions

preoperative ANRI is an independent effective predictor of prognosis for patients with HCC, higher levels of ANRI predict poorer outcomes and the combining ANRI and NLR increases the prognostic accuracy of testing.

Clinical evaluation of macrophages in cancer: role in treatment, modulation and challenges

The focus of immunotherapeutics has been placed firmly on anti-tumour T cell responses. Significant progress has been made in the treatment of both local and systemic malignancies, but low response rates and rising toxicities are limiting this approach. Advancements in the understanding of tumour immunology are opening up a new range of therapeutic targets, including immunosuppressive factors in the tumour microenvironment. Macrophages are a heterogeneous group of cells that have roles in innate and adaptive immunity and tissue repair, but become co-opted by tumours to support tumour growth, survival, metastasis and immunosuppression. Macrophages also support tumour resistance to conventional therapy. In preclinical models, interference with macrophage migration, macrophage depletion and macrophage re-education have all been shown to reduce tumour growth and support anti-tumour immune responses. Here we discuss the role of macrophages in prognosis and sensitivity to therapy, while examining the significant progress which has been made in modulating the behaviour of these cells in cancer patients.

[Paraneoplastic Leukocytosis and Thrombocytosis as Prognostic Biomarkers in Non-small Cell Lung Cancer]

Background and Objectives

Search for inexpensive laboratory markers have identified associations between blood counts and lung cancer outcomes. In this study, we evaluated the prognostic value of paraneoplastic leukocytosis (p-Leukocytosis) and paraneoplastic thrombocytosis (p-Thrombocytosis) in patients with non-small cell lung cancer (NSCLC). We also studied their relation to the expression of commonly detected molecular markers.

Methods

We conducted a retrospective chart review on 571 consecutive NSCLC patients over a 10 year period. Blood counts were recorded at the time of cancer diagnosis. Kaplan-Meier survival curves were used to compare overall survival (OS) between patients with and without p-Leukocytosis (or) p-Thrombocytosis (p-Leuko/Thrombocytosis). Cox regression was used to determine if leukocytosis/thrombocytosis was a predictor of OS in NSCLC.

Results

Patients with p-Leukocytosis and p-Thrombocytosis had a significantly poorer survival compared patients with normal blood counts (P < 0.001). In a multivariate survival analysis, both continued to correlate even when adjusted for histology, gender, stage and chemotherapy (P < 0.01, 0.03 respectively). Stage Ⅰ and Ⅱ NSCLC with p-Leuko/Thrombocytosis did not perform poorly compared to stage Ⅰ/Ⅱ NSCLC patients without paraneoplasia. Patients with the combined leukothrombocytosis syndrome did not have worse outcomes compared to those with either paraneoplastic syndrome alone.

Conclusions

p-Leuko/Thrombocytosis is an accessible laboratory parameter of prognostic value in NSCLC. Evidence of p-Leuko/Thrombocytosis portends poor survival. The role of various cytokines in tumor pathobiology provides a rationale for identifying cytokine factors responsible for the paraneoplasia and administering anti-cytokine therapies alongside traditional chemotherapy in an attempt to improve survival outcomes in these subset of patients.

The IL-17-Th1/Th17 pathway: an attractive target for lung cancer therapy?

INTRODUCTION

There is strong pharmaceutical development of agents targeting the IL-17-TH17 pathway for the treatment of psoriasis (Ps) and psoriatic arthritis (PsA). Lung cancer accounts for 28% of all cancer-related deaths worldwide, and roughly 80% of patients with newly-diagnosed non-small cell lung cancer (NSCLC) present with metastatic disease, with a poor prognosis of around 12 months. Therefore, there is a high unmet medical need for the development of new and potent systemic treatments in this deadly disease. The emergence of immunotherapies such as anti-PD-1 or anti-PDL1 as candidate therapies in non-small cell lung cancer (NSCLC) indicates that targeting critical immuno-modulatory cytokines including those within the IL-17-Th1/Th17 axis may have proven benefit in the treatment of lung cancer. Areas covered: In this review we describe the current evidence for aberrant IL-17-Th1/Th17 settings in cancer, particularly with regard to targeting this axis in NSCLC. We further discuss the current agents under pharmaceutical development which could potentially target this axis, and discuss the current limitations and areas of concern regarding the use of these in lung cancer. Expert opinion: Current evidence suggests that moving forward agents targeting the IL-17-Th1/Th17 pathway may have novel new oncoimmunology indications in the treatment paradigm for NSCLC.

CSF2 Overexpression Is Associated with STAT5 Phosphorylation and Poor Prognosis in Patients with Urothelial Carcinoma

Background: Urothelial carcinoma (UC) commonly occurs in the urinary bladder (UB) and rarely in upper the upper urinary tract (UT). Its molecular pathogenesis, however, remains obscure. Though the constitutive phosphorylation of Signal Transducer and Activator of Transcription 5 (STAT5) is an important part of carcinogenesis generally, researchers have not systematically investigated this process specifically in relation to UC. The present study addresses this gap. Through data mining a published transcriptomic database of UBUCs (GSE32894), it identified Colony Stimulating Factor 2 (CSF2) as the stepwise upregulated gene of much significance among those related to the positive regulation of tyrosine phosphorylation of STAT5 (GO:0042523). Since the phosphorylation of STAT5, a key process in the development of UC, is closely associated with CSF2, we then examine CSF2 transcript and protein expression, justifying their association with clinicopathological features and survival in our well-established cohort of patients with UC.

Design: Laser capture microdissection in conjunction with real-time qRT-PCR are used to detect CSF2 transcript levels in 24 UBUCs and 6 non-tumor urothelium samples. We then used the H-score method to evaluate the immunohistochemistry in order to determine CSF2 protein expression in 296 UBUCs and 340 UTUCs, respectively. After correlating protein expression status with key clinicopathological features, the prognostic significance of CSF2 protein expression was determined for disease-specific survival (DSS) and metastasis-free survival (MeFS).

Results: We exclusively detected the CSF2 transcript, which was stepwise upregulated in tumor lesions (p=0.010). In both groups of UC we found overexpression of CSF2 significantly related to incremental pT status (UTUC, p=0.011; UBUC, p<0.001), as well as with perineural invasion (UTUC, p=0.002; UBUC, p=0.001). Univariate analysis found a close correlation between CSF2 overexpression and unfavorable prognosis for both DSS (UTUC, p=0.0001; UBUC, p<0.0001) and MeFS (UTUC, p=0.0001; UBUC, p=0.0002). High expression of CSF2 still remained prognostically for DSS (UTUC, p=0.015; UBUC, p=0.004) and MeFS (UTUC, p=0.008; UBUC, p=0.027) in multivariate comparison.

Conclusion: Our data showed that overexpression of CSF2 was inferred in advanced disease status and poor clinical outcomes for both UTUC and UBUC patients, suggesting that CSF2 may serve as an important prognosticator and a potential therapeutic target of UC.

A versatile technique for the in vivo imaging of human tumor xenografts using near-infrared fluorochrome-conjugated macromolecule probes

Here, we present a versatile method for detecting human tumor xenografts in vivo, based on the enhanced permeability and retention (EPR) effect, using near-infrared (NIR) fluorochrome-conjugated macromolecule probes. Bovine serum albumin (BSA) and two immunoglobulins—an anti-human leukocyte antigen (HLA) monoclonal antibody and isotype control IgG_2a—were labeled with XenoLight CF770 fluorochrome and used as NIR-conjugated macromolecule probes to study whole-body imaging in a variety of xenotransplantation mouse models. NIR fluorescent signals were observed in subcutaneously transplanted BxPC-3 (human pancreatic cancer) cells and HCT 116 (colorectal cancer) cells within 24 h of NIR-macromolecule probe injection, but the signal from the fluorochrome itself or from the NIR-conjugated small molecule (glycine) injection was not observed. The accuracy of tumor targeting was confirmed by the localization of the NIR-conjugated immunoglobulin within the T-HCT 116 xenograft (in which the orange-red fluorescent protein tdTomato was stably expressed by HCT 116 cells) in the subcutaneous transplantation model. However, there was no significant difference in the NIR signal intensity of the region of interest between the anti-HLA antibody group and the isotype control group in the subcutaneous transplantation model. Therefore, the antibody accumulation within the tumor in vivo is based on the EPR effect. The liver metastasis generated by an intrasplenic injection of T-HCT 116 cells was clearly visualized by the NIR-conjugated anti-HLA probe but not by the orange-red fluorescent signal derived from the tdTomato reporter. This result demonstrated the superiority of the NIR probes over the tdTomato reporter protein at enhancing tissue penetration. In another xenograft model, patient-derived xenografts (PDX) of LC11-JCK (human non-small cell lung cancer) were successfully visualized using the NIR-conjugated macromolecule probe without any genetic modification. These results suggested that NIR-conjugated macromolecule, preferably, anti-HLA antibody probe is a valuable tool for the detection of human tumors in experimental metastasis models using whole-body imaging.

Pretreatment neutrophil count as an independent prognostic factor in advanced non-small-cell lung cancer: an analysis of Japan Multinational Trial Organisation LC00-03

We examined the impact of pretreatment neutrophil count on survival in patients with advanced non-small-cell lung cancer (NSCLC). A total of 388 chemo-naïve patients with stage IIIB or IV NSCLC from a randomised controlled trial were evaluated. The effects of pretreatment peripheral blood neutrophil, lymphocyte and monocyte counts and neutrophil-lymphocyte ratio on survival were examined using the proportional hazards regression model to estimate hazard ratios after adjustment for covariates. The optimal cut-off value was determined by proportional hazards regression analysis with the minimum P-value approach and shrinkage procedure. After adjustment for prognostic factors, the pretreatment elevated neutrophil count was statistically significantly associated with short overall (P=0.0008) and progression-free survival (P=0.024), whereas no association was found between prognosis and lymphocyte or monocyte count. The cut-off value selected for neutrophil count was 4500 mm(-3) (corrected hazard ratio, 1.67; 95% confidence interval (CI), 1.09-2.54). The median survival time was 19.3 months (95%CI, 16.5-21.4) for the low-neutrophil group (4500 mm(-3), n=204) and was 10.2 months (95%CI, 8.0-12.3) for the high-neutrophil group (4500 mm(-3), n=184). We confirmed that pretreatment elevated neutrophil count is an independent prognostic factor in patients with advanced NSCLC receiving modern chemotherapy. Neutrophil count is easily measured at low cost, and it may be a useful indicator of patient prognosis.

Effect of serum deprivation on constitutive production of granulocyte-colony stimulating factor and granulocyte macrophage-colony stimulating factor in lung cancer cells

We previously established 2 lung cancer cell lines, OKa-C-1 and MI-4, which constitutively produce an abundant dose of granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF). Many other cases with G-CSF or GM-CSF producing tumors have been reported up to the present. However, the biological properties of the overproduction of G-CSF and GM-CSF by tumor cells have not been well known. Several reports demonstrated the presence of an autocrine growth loop for G-CSF and GM-CSF in nonhematopoietic tumor cells. We showed that exogenous G-CSF and GM-CSF stimulated cell growth in a dose-dependent manner in OKa-C-1 and MI-4 cells. We could detect the presence of G-CSF and GM-CSF receptors in both cell lines by RT-PCR analysis. We have previously shown that inflammatory cytokines, tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta enhance the expression of G-CSF and GM-CSF in the cell lines. However, the factors that regulate constitutive production of G-CSF or GM-CSF by tumor cells are still unknown well. In our study, we first reported that serum deprivation stimulated constitutive production of G-CSF and GM-CSF by lung tumor cells through activation of nuclear factor (NF)-kappaB and p44/42 mitogen-activated protein kinase (MAPK) pathway signaling. We suggest that G-CSF and GM-CSF constitutively produced by tumor cells could grow tumor itself and rescue tumor cells from the cytotoxicity of serum deprivation.

Antitumor activity of the intratumoral injection of fowlpox vectors expressing a triad of costimulatory molecules and granulocyte/macrophage colony stimulating factor in mesothelioma

Deficiency in costimulatory molecule expression has been implicated in the ability of tumors to escape immune effectors. The activity of the intratumoral administration of recombinant fowlpox vectors expressing a triad of costimulatory molecules (rF-TRICOM) was evaluated in the asbestos-induced AB12 and AC29 mouse models of mesothelioma. Mesothelioma cell infected with rF-TRICOM expressed high levels of the costimulatory molecules. Prolongation of survival was observed in mice receiving rF-TRICOM in AB12 and AC29 intraperitoneal models. Complete tumor regressions were observed in mice receiving intratumoral rF-TRICOM in the AB12 subcutaneous tumor model. Tumor regressions were associated with the development of serum IgG reactivities to mesothelioma-associated determinants and specific systemic cytolytic activity, and responding mice were capable of rejecting tumors upon re-challenge. Antitumor activity was also observed in mice with established AB12 tumor vaccinated with irradiated rF-TRICOM-infected AB12 cells. The antitumor activity of intratumoral rF-TRICOM was superior to that of the intratumoral injection of a fowlpox vector expressing granulocyte-macrophage colony stimulating factor (rF-GM-CSF). AB12 and AC29 tumors were found to produce GM-CSF and to have substantial macrophage infiltration. Production of GM-CSF decreased in vivo in tumors injected with rF-TRICOM. rF-TRICOM and wild-type fowlpox inhibited the growth of AB12 and AC29 cells in vitro; less inhibition was observed with rF-GM-CSF. These results indicate that the intratumoral injection of rF-TRICOM has significant activity in mouse models of mesothelioma and can elicit a systemic antitumor immune response. The results also suggest potential limitations to the intratumoral administration of cytokines, such as GM-CSF, in mesothelioma.

Analysis of the immunological microenvironment at the tumor site in patients with non-small cell lung cancer

BACKGROUND AND AIMS

Inactivation of tumor-infiltrating lymphocytes by immunomodulating cytokines shed by tumor cells into the tumor local microenvironment might be a potential escape strategy of various tumors from immune-immediate killing. Here, we provide an analysis of the cytokine profile at the tumor site in patients with non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

Using in situ hybridization (ISH), we determined the mRNA expression in lymphocytes and tumor cells for IL-2, INF-gamma, IL-12 (p40), IL-18, IL-4, IL-10, TGF-beta1, IL-1, IL-3, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), TNF-alpha, and TGF-alpha in five fresh pleural effusion samples and 18 tumor tissue samples of patients with NSCLC.

RESULTS

In pleural effusion as well as in tumor tissue of NSCLC patients, the mRNA expression of IL-4, IL-10, TGF-alpha, and TGF-beta1 was significantly higher than that of IL-2, IL-12, IL-18 and INF-gamma. In contrast, the analysis of tuberculosis pleural effusion samples revealed lower mRNA levels for all cytokines and did not show any significant difference among them.

CONCLUSION

The predominant mRNA expression of type II and immunosuppressive cytokines in pleural effusion and tumor tissue of NSCLC patients mirrors an immunosuppressive state in the immunological microenvironment. The present study may, therefore, help to elucidate mechanisms of tumor escape and contribute to the development of an effective immunomodulatory treatment of NSCLC.

ETS2 is involved in protein kinase C-activated expression of granulocyte-macrophage colony-stimulating factor in human non-small lung carcinoma cell line, A549

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine expressed in the non-small lung carcinoma cells (NSCLC). However, transcriptional regulation of GM-CSF is not well characterized in NSCLC. In this study we found that two cis-acting ETS family consensus sites are important for transcriptional regulation of GM-CSF in A549 human lung carcinoma cells. These two sites are located separately at around -40 and -100 bp from the transcription start site. Results of transient transfection assays with A549 cells indicated that ETS2 had a strong positive effect on GM-CSF promoter activity. Furthermore, this activity was enhanced by protein kinase C activator, phorbol 12-myristate 13-acetate (PMA), in an ETS consensus-dependent manner, while PMA could also enhance the expression level of ETS2. The protein kinase C inhibitors decreased GM-CSF promoter activity induced by the protein kinase C activator PMA. We also found that antisense ETS2 mRNA decreased PMA-induced GM-CSF promoter activity, supporting the possibility that ETS2 is involved in protein kinase C-induced GM-CSF transcriptional function. Endogenous expression of GM-CSF mRNA was increased by ETS2 transfection and the increased expression was further enhanced by PMA. These data indicate that GM-CSF is up-regulated by ETS2, a target of protein kinase C.

Cyclooxygenase-2 inhibitor NS-398 suppresses cell growth and constitutive production of granulocyte-colony stimulating factor and granulocyte macrophage-colony stimulating factor in lung cancer cells

We previously established two lung cancer cell lines, OKa-C-1 and MI-4, which constitutively produce abundant granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage-colony stimulating factor (GM-CSF). Inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta stimulated the expression of G-CSF, GM-CSF, and cyclooxygenase (COX)-2 in the two cell lines. It is known that increased COX-2 activity promotes tumor growth and induces G-CSF and GM-CSF expression in non-malignant cells, and that selective COX-2 inhibitors inhibit the growth of some types of malignant cells. Therefore, we hypothesized that inhibition of COX-2 activity might suppress constitutive production of G-CSF or GM-CSF in addition to reducing the growth of malignant cells. We confirmed that the selective COX-2 inhibitor, NS-398 suppressed the constitutive production of G-CSF and GM-CSF, and the cell growth in both OKa-C-1 and MI-4 cell lines. Prostaglandin E2 (PGE2) reversed the inhibitions of G-CSF and GM-CSF expression, as well as cell growth, by NS-398. This result confirms that the effects of NS-398 are based on the inhibition of COX activity. Some studies have indicated that nuclear factor kappa B (NF-kappaB) or MAPK (mitogen-activated protein kinase) activation is related to upregulation of G-CSF, GM-CSF or COX-2 expression in some types of cells. Therefore, we examined if the actions of NS-398 might be mediated by the MAP kinase pathway or NF-kappaB activity in OKa-C-1 and MI-4 cells. We found that NS-398 inhibits G-CSF and GM-CSF production and cell growth through an extracellular signal-regulated kinase kinase (MEK) signaling pathway in these cell lines. The prognosis of non-small cell lung cancer showing G-CSF gene expression is significantly worse. G-CSF overproduction by tumor cells is observed at an advanced clinical stage. Our findings imply that a COX-2 inhibitor might improve the prognosis of patients with lung cancer through the reduction of G-CSF or GM-CSF.

Probing the cons and pros of lectin-induced immunomodulation: case studies for the mistletoe lectin and galectin-1

When imagining to monitor animal cells through a microscope with resolution at the molecular level, a salient attribute of their surfaces will be the abundance of glycan chains. They present galactosides at their termini widely extending like tentacles into the extracellular space. Their spatial accessibility and their potential for structural variability endow especially these glycan parts with capacity to act as docking points for molecular sensors (sugar receptors such as lectins). Binding and ligand clustering account for transmission of post-binding signals into the cell interior. The range of triggered activities has turned plant lectins into popular tools in cell biology and immunology. Potential for clinical application has been investigated rigorously only in recent years. As documented in vitro and in vivo for the galactoside-specific mistletoe lectin, its apparent immunomodulatory capacity reflected in upregulation of production of proinflammatory cytokines will not necessarily be clinically favorable but a double-edged sword. In fact, lectin application has been shown to stimulate tumor growth in cell lines, histocultures of human tumors and in two animal models using chemical carcinogenesis or tumor transplantation. When testing immunological effects of the endogenous lectin galectin-1, protection against disorders mediated by activated T cells came up for consideration. Elimination of these cells via CD7-dependent induction of apoptosis, and a shift to the Th2 response by the galectin, are factors to ameliorate disease states. This result encourages further efforts with other galectins. Functional redundancy, synergism, diversity or antagonism among galectins are being explored to understand the actual role of this class of endogenous lectins in inflammation. Regardless of the results of further preclinical testing for galectin-1, these two case studies break new ground in our understanding how glycans as ligands for lectins convey reactivity to immune cells, with impact on the course of a tumor or autoimmune disease.

Evidence for stimulation of tumor proliferation in cell lines and histotypic cultures by clinically relevant low doses of the galactoside-binding mistletoe lectin, a component of proprietary extracts

The toxic galactoside-specific lectin from mistletoe, a component of proprietary extracts with unproven efficacy in oncology, exhibits capacity to trigger enhanced secretion of proinflammatory cytokines at low doses (ng/ml or ng/kg body weight) and reductions of cell viability with increasing concentrations. To infer any tumor selectivity of this activity, cytofluorimetric and cell growth assays with a variety of established human tumor cell lines were performed. Only quantitative changes were apparent, and the toxicity against tumor cells was within the range of that of the tested fibroblast preparations from 5 donors. No indication for any tumor selectivity was observed. In kinetic studies with 8 sarcoma and 4 melanoma lines, this evidence for quantitative variability of the response in interindividual comparison was further underscored. At 50 pg lectin/ml x 10(5) cells, even a growth-stimulatory impact was noted in 5 of 12 tested cases. To mimic in vivo conditions with presence of cytokine-secreting inflammatory and stromal cells, exposure to the lectin was extended to histotypic cultures established from 30 cases of surgically removed tumor. As salient result, 5 specimens from 4 of the 8 tested tumor classes responded with a significant increase of [3H]-thymidine incorporation relative to controls during the culture period of 72 hours, when the lectin was present at a concentration in the described immunomodulatory range (1 ng/ml). A relation of this activity to the extent of the actual proliferative status of the reactive samples could not be delineated. Therefore, a non-negligible percentage of the established tumor cell lines (e.g., 3 from 8 sarcoma lines) can be markedly stimulated by the lectin at a very low dose and with dependence on the cell type. Furthermore, the feasibility to elicit a significant growth enhancement is likewise documented for human tumor explants in 16.6% of the examined cases. In view of the uncontrolled application of lectin-containing extracts in alternative/complementary medicine, the presented results on unquestionably adverse lectin-dependent effects in two culture systems call for rigorous examination of the clinical safety of this unconventional, scientifically entirely experimental treatment modality.

Constitutive expression of G-CSF and GM-CSF in human skin carcinoma cells with functional consequence for tumor progression

Tumor progression is characterized by an increasing escape of tumor cells from the growth control of their microenvironment, often caused by aberrant expression of growth factors. In the human skin carcinoma model system, based on the HaCaT keratinocyte line, tumor progression to high-grade malignant cells is associated with constitutive expression and secretion of the hematopoietic growth factors G-CSF and GM-CSF in vitro and in vivo. All HaCaT keratinocyte variants express the G-CSF and the GM-CSF receptors at levels comparable to normal keratinocytes. Consequently, they exhibit a stimulation of cell proliferation and migration in culture when treated with these factors. Moreover, both proliferation and migration of the high-grade malignant cells were strongly inhibited by neutralizing antibodies to G-CSF and GM-CSF, respectively. This demonstrates the functional role of these factors in high-grade malignant HaCaT cells through an autocrine mechanism in vitro and implies their significance in tumor progression in vivo. In light of the increasing use of G-CSF and GM-CSF in adjuvant tumor therapy, our data, as well as those discussed for head-and-neck tumors and gliomas, warrant a careful re-evaluation of the clinical application of both factors.