Growth inhibition and apoptosis by an active component of OK-432, a streptococcal agent, via Toll-like receptor 4 in human head and neck cancer cell lines

Immunoexpression pattern of TLR3 and TLR7 in minor salivary gland adenoid cystic carcinoma and its role in prognosis

OBJECTIVES

Adenoid cystic carcinoma (ACC) of the salivary glands has poor long-term prognosis and a high metastatic rate. Toll-like receptors (TLRs), first-line immune activators, have been associated with both tumor progression and suppression. We aimed to study TLR3 and TLR7 behavior in ACC.

MATERIALS AND METHODS

We studied TLR3 and TLR7 immunoexpression of 46 minor salivary gland ACCs diagnosed at the Department of Otorhinolaryngology - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland over the period 1974-2012. The associations of TLR3 and TLR7 immunoexpression with clinicopathological factors were evaluated by χ2-test and Fisher's exact test.

RESULTS

In the majority of samples, both TLR3 and TLR7 were immunoexpressed in cytoplasm. The immunoexpression was heterogeneous between individual tumors. Stronger TLR7 immunoexpression associated with recurrence rate and poorer disease-specific survival (DSS). TLR3 did not associate significantly with survival although we found an inverse correlation between TLR3 and TLR7 immunopositivity. Hence, when TLR3 immunoexpression was negative or mild, TLR7 immunoexpression was moderate to strong, and vice versa.

CONCLUSIONS

TLR3 and TLR7 are immunoexpressed in minor salivary gland ACC. TLR7 is potentially an independent prognostic marker for recurrence rate and DSS.

Cudraflavone B induces human glioblastoma cells apoptosis via ER stress-induced autophagy

BACKGROUND

Glioblastoma (GBM) is the most common malignant intracranial tumor with a low survival rate. However, only few drugs responsible for GBM therpies, hence new drug development for it is highly required. The natural product Cudraflavone B (CUB) has been reported to potentially kill a variety of tumor cells. Currently, its anit-cancer effect on GBM still remains unknown. Herein, we investigated whether CUB could affect the proliferation and apoptosis of GBM cells to show anti-GBM potential.

RESULTS

CUB selectively inhibited cell viability and induced cell apoptosis by activating the endoplasmic reticulum stress (ER stress) related pathway, as well as harnessing the autophagy-related PI3K/mTOR/LC3B signaling pathway. Typical morphological changes of autophagy were also observed in CUB treated cells by microscope and scanning electron microscope (SEM) examination. 4-Phenylbutyric acid (4-PBA), an ER stress inhibitor, restored the CUB-caused alteration in signaling pathway and morphological change.

CONCLUSIONS

Our finding suggests that CUB impaired cell growth and induced cell apoptosis of glioblastoma through ER stress and autophagy-related signaling pathways, and it might be an attractive drug for treatment of GBM.

MD2 Is a Potential Biomarker Associated with Immune Cell Infiltration in Gliomas

BACKGROUND

Glioma is the most common primary malignant tumor in the central nervous system. Myeloid differentiation protein 2 (MD2) acts as a coreceptor of toll-like receptor 4 (TLR4) to mediate innate immune response. However, the actual roles of MD2 in the regulation of progression and immune cell infiltration in gliomas remain largely unclear. This study aims to explore whether MD2 could be an independent prognostic factor through the mediation of immune cell infiltration in gliomas.

METHODS

The mRNA expression and DNA methylation differential analyses of MD2 were performed using CGGA, TCGA and Rembrandt databases and survival analyses were performed using Kaplan-Meier plotter. Univariate and multivariate Cox regression was applied to analyze the prognostic value of MD2 and nomograms were constructed to evaluate the clinical value of MD2. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to analyze MD2-related signal pathways. Furthermore, correlations between MD2 and immune cell infiltration were calculated by TIMER and CIBERSOPT. The correlation between MD2 expression and the infiltrations of macrophages and neutrophils was experimentally verified by the knockdown of MD2 expression using small interfering RNA (siRNA) in glioma cells.

RESULTS

We found that MD2 was overexpressed and associated with a poor prognosis in gliomas. Meanwhile, higher expression of MD2 could be a result of lower DNA methylation of MD2 gene in gliomas. In addition, univariate and multivariate Cox regression analysis indicated that MD2 could be an independent prognostic factor for gliomas. Further functional enrichment analysis revealed that the functions of MD2 were closely related to immune responses. Moreover, the expression level of MD2 was strongly correlated with the infiltration and polarization of pro-tumor phenotype of tumor-associated macrophages and tumor-associated neutrophils in gliomas.

CONCLUSIONS

These findings have provided strong evidence that MD2 could be served as a valuable immune-related biomarker to diagnose and predict the progression of gliomas.

MD2 Is a Potential Biomarker Associated with Immune Cell Infiltration in Gliomas

BACKGROUND

Glioma is the most common primary malignant tumor in the central nervous system. Myeloid differentiation protein 2 (MD2) acts as a coreceptor of toll-like receptor 4 (TLR4) to mediate innate immune response. However, the actual roles of MD2 in the regulation of progression and immune cell infiltration in gliomas remain largely unclear. This study aims to explore whether MD2 could be an independent prognostic factor through the mediation of immune cell infiltration in gliomas.

METHODS

The mRNA expression and DNA methylation differential analyses of MD2 were performed using CGGA, TCGA and Rembrandt databases and survival analyses were performed using Kaplan-Meier plotter. Univariate and multivariate Cox regression was applied to analyze the prognostic value of MD2 and nomograms were constructed to evaluate the clinical value of MD2. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to analyze MD2-related signal pathways. Furthermore, correlations between MD2 and immune cell infiltration were calculated by TIMER and CIBERSOPT. The correlation between MD2 expression and the infiltrations of macrophages and neutrophils was experimentally verified by the knockdown of MD2 expression using small interfering RNA (siRNA) in glioma cells.

RESULTS

We found that MD2 was overexpressed and associated with a poor prognosis in gliomas. Meanwhile, higher expression of MD2 could be a result of lower DNA methylation of MD2 gene in gliomas. In addition, univariate and multivariate Cox regression analysis indicated that MD2 could be an independent prognostic factor for gliomas. Further functional enrichment analysis revealed that the functions of MD2 were closely related to immune responses. Moreover, the expression level of MD2 was strongly correlated with the infiltration and polarization of pro-tumor phenotype of tumor-associated macrophages and tumor-associated neutrophils in gliomas.

CONCLUSIONS

These findings have provided strong evidence that MD2 could be served as a valuable immune-related biomarker to diagnose and predict the progression of gliomas.

Novel Immunotherapeutic Approaches for Head and Neck Squamous Cell Carcinoma

The immune system plays a key role in preventing tumor formation by recognizing and destroying malignant cells. For over a century, researchers have attempted to harness the immune response as a cancer treatment, although this approach has only recently achieved clinical success. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and is associated with cigarette smoking, alcohol consumption, betel nut use, and human papillomavirus infection. Unfortunately, worldwide mortality from HNSCC remains high, partially due to limits on therapy secondary to the significant morbidity associated with current treatments. Therefore, immunotherapeutic approaches to HNSCC treatment are attractive for their potential to reduce morbidity while improving survival. However, the application of immunotherapies to this disease has been challenging because HNSCC is profoundly immunosuppressive, resulting in decreased absolute lymphocyte counts, impaired natural killer cell function, reduced antigen-presenting cell function, and a tumor-permissive cytokine profile. Despite these challenges, numerous clinical trials testing the safety and efficacy of immunotherapeutic approaches to HNSCC treatment are currently underway, many of which have produced promising results. This review will summarize immunotherapeutic approaches to HNSCC that are currently undergoing clinical trials.

Low expression of nuclear Toll-like receptor 4 in laryngeal papillomas transforming into squamous cell carcinoma

OBJECTIVE

The malignant transformation rate of recurrent respiratory papillomatosis (RRP), a disease caused by human papillomavirus (HPV), has varied significantly. Cells of the human immune system express toll-like receptors (TLRs) that recognize particles from viruses and bacteria; TLRs are also present on tumor cells, and down-regulation of TLRs has been shown during the progression of HPV-associated neoplasia. The aim of this study was to determine the malignant transformation rate of laryngeal papillomas (LPs) and analyze the potential of TLR2, TLR4, and TLR9 immunoexpression as indicators of the increased cancer risk.

STUDY DESIGN

Retrospective case-control study.

SETTING

Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.

SUBJECTS AND METHODS

We reviewed all patients with RRP treated for LPs between 1975 and 2011. Data from the Finnish Cancer Registry confirmed the number of patients diagnosed with laryngeal squamous cell carcinoma (LSCC). Laryngeal tissue specimens from patients developing LSCC were subjected to TLR2, TLR4, and TLR9 immunohistochemistry. Nine patients with RRP without malignant transformation and 19 patients with LSCC without a pre-existing LP served as controls.

RESULTS

Nine of 324 patients (2.8%) with RRP developed LSCC. The intensity of nuclear staining of TLR4 was significantly lower in LPs transforming into LSCC than in LPs without malignant transformation. The expression of cytoplasmic TLR4 in LSCC correlated with tumor grade and T stage. Cytoplasmic TLR9 expression was significantly lower in LPs than in LSCC.

CONCLUSION

The expression of TLR4 may serve as a predictive marker of malignant transformation in LPs. High immunoexpression of cytoplasmic TLR4 in LSCC was associated with a more aggressive disease.

Trial Watch: Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology, we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.

Dual character of Toll-like receptor signaling: pro-tumorigenic effects and anti-tumor functions

As a major class of pattern-recognition receptors, Toll-like receptors (TLRs) play a critical role in defense against invading pathogens. Increasing evidence demonstrates that, in addition to infection, TLRs are involved in other important pathological processes, such as tumorigenesis. Activation of TLRs results in opposing outcomes, pro-tumorigenic effects and anti-tumor functions. TLR signaling can inhibit apoptosis and promote chronic inflammation-induced tumorigenesis. TLR activation in tumor cells and immune cells can induce production of cytokines, increase tumor cell proliferation and apoptosis resistance, promote invasion and metastasis, and inhibit immune cell activity resulting in tumor immune escape. In contrast, the engagement of other TLRs directly induces growth inhibition and apoptosis of tumor cells and triggers activation of immune cells enhancing anti-tumor immune responses. Thus, the interpretation of the precise function of each TLR in tumors is very important for targeting TLRs and using TLR agonists in tumor therapy. We review the role of TLR signaling in tumors and discuss the factors that affect outcomes of TLR activation.

Effectiveness of OK-432 (Sapylin) to reduce seroma formation after axillary lymphadenectomy for breast cancer

BACKGROUND

The occurrence of seroma formation after axillary lymphadenectomy for breast cancer cannot be ignored. Various approaches have been used in an effort to reduce it, but these results are still controversial. We aimed to describe a new method of application of OK-432 (Sapylin, heat-treated Su strain of Streptococcus) to reduce seroma formation after axillary lymphadenectomy for breast cancer and to verify the safety and efficacy of it as a beneficial supplement for conventional surgery.

METHODS

A prospective, randomized analysis of consecutive quadrantectomy or mastectomy plus axillary lymphadenectomy using or not using OK-432 was designed. From July 2010 to November 2011, a total of 111 patients were enrolled in this prospective, randomized study and completed the follow-up. OK-432 applied to the axillary fossa plus placement of closed suction drainage was used in 54 patients (the experimental group); placement of closed suction drainage was used in 57 patients (the control group).

RESULTS

There were no statistical significance between the two groups in terms of age, body mass index, treatment received, tumor size, number of removed lymph nodes, and lymph node status. Postoperative drainage magnitude and duration were significantly reduced in the experimental group (P = 0.008 and 0.003, respectively). One week after hospital discharge, fewer patients developed a palpable seroma in the experimental group: 10 in the experimental group versus 28 in the control group (P = 0.001). Fewer seromas needed aspiration (mean 1 [range 0-3] in the experimental group vs. mean 4 [range 1-5] in the control group; P < 0.001). There were no significant differences in terms of the incidence of complications associated with axillary lymphadenectomy (P = 0.941).

CONCLUSIONS

OK-432 is a feasible and safe option for axillary lymphadenectomy for breast cancer. The use of it does not always prevent seroma formation, but it can reduce drainage magnitude and duration, as well as decrease the incidence of seroma after the removal of drainage. It may be increasingly conducted in day surgery clinics.