Mammalian target of rapamycin (mTOR) is involved in the survival of cells mediated by chemokine receptor 7 through PI3K/Akt in metastatic squamous cell carcinoma of the head and neck

Analysis of the effect of CCR7 on the microenvironment of mouse oral squamous cell carcinoma by single-cell RNA sequencing technology

BACKGROUND

Studies have shown that CCR7, an important inflammatory factor, can promote the proliferation and metastasis of oral squamous cell carcinoma (OSCC), but its role in the tumor microenvironment (TME) remains unclear. This paper explores the role of CCR7 in the TME of OSCC.

METHODS

In this work, we constructed CCR7 gene knockout mice and OSCC mouse models. Single-cell RNA sequencing (scRNA-seq) and bioinformatics were used to analyze the differences in the OSCC microenvironment between three CCR7 gene knockout mice (KO) and three wild-type mice (WT). Immunohistochemistry, immunofluorescence staining, and flow cytometry were used to analyze the expression of key genes in significantly different cell types between the KO and WT groups. An in vitro experiment was used to verify the effect of CCR7 on M2 macrophage polarization.

RESULTS

In the mouse OSCC models, the tumor growth rate in the KO group was significantly lower than that in the WT group. Eight main cell types (including tumor cells, fibroblasts, macrophages, granulocytes, T cells, endothelial cells, monocytes, and B cells) were identified by Seurat analysis. The scRNA-seq results showed that the proportion of tumor cells was lower, but the proportion of inflammatory cells was significantly higher in the KO group than in the WT group. CellPhoneDB analysis results indicated a strong interaction relationship between tumor cells and macrophages, T cells, fibroblasts, and endothelial cells. Functional enrichment results indicated that the expression level of the Dusp1 gene in the KO group was generally higher than that in the WT group in various cell types. Macrophage subclustering results indicated that the proportion of M2 macrophages in the KO group was lower than that in the WT group. In vitro experimental results showed that CCR7 can promote M2 macrophage polarization, thus promoting the proliferation, invasion and migration of OSCC cells.

CONCLUSIONS

CCR7 gene knockout can significantly inhibit the growth of mouse oral squamous cell carcinoma by promoting the polarization of M2 macrophages.

CC chemokine receptor 7 promotes macrophage recruitment and induces M2-polarization through CC chemokine ligand 19&21 in oral squamous cell carcinoma

PURPOSE

This study aimed to investigate the impact of CC chemokine receptor 7 (CCR7) on the recruitment and polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC).

METHODS

We analyzed CCR7 expression pattern, clinicopathological significance, and its association with M2 macrophage infiltration in OSCC by bioinformatic methods. Small interfering RNA (siRNA) was utilized to silence CCR7 in OSCC cells. Conditioned media (CM) was harvested from transfected OSCC cells to establish a co-culture model of THP-1 derived macrophages and OSCC cells. Transwell assay and cell adhesion assay were performed to examine the effect of CCR7 on macrophages recruitment and adhesion. Cytoskeleton was labelled by phalloidin to observe macrophage morphological changes. Moreover, phenotypic alteration of macrophages was measured using quantitative real-time PCR (qRT-PCR), flow cytometry, and immunofluorescence (IF) staining. Ultimately, recombinant human CCL19 and CCL21 were added into the medium of THP-1 derived macrophages to explore their effects on polarization in vitro.

RESULTS

In OSCC patients, the overexpression of CCR7 positively correlated with lymph node metastasis and M2 macrophage infiltration. Macrophage not only exhibited enhanced migration, invasion and adhesion abilities, but also appeared more spindle and branched in vitro when treated with CM from OSCC cells. However, these phenomena were abrogated with knockdown of CCR7. We also discovered that inhibition of CCR7 in OSCC cells suppressed TAMs polarization to an M2 phenotype. In addition, recombinant human CCL19 and CCL21 promoted macrophage M2-polarization in vitro.

CONCLUSION

CCR7 in OSCC cells promoted recruitment and M2-polarization of THP-1 derived macrophages in vitro by regulating production of CCL19 and CCL21.

The Overexpression of Fibronectin 1 Promotes Cancer Progression and Associated with M2 Macrophages Polarization in Head and Neck Squamous Cell Carcinoma Patients

Purpose

This study aimed to investigate the biological roles of fibronectin 1 (FN1) in head and neck squamous cell carcinoma (HNSCC) and its effects on macrophage M2 polarization.

Methods

We analyzed FN1 expression pattern and examined its clinical relevance in HNSCC progression by bioinformatic analysis. Small interfering RNA (siRNA) was utilized to silence FN1 in HNSCC cells. Cell counting kit-8 (CCK-8) assay, colony formation assay, Transwell assay and wound healing assay were performed to reveal the effect of FN1 on malignant behaviors of HNSCC cells. Moreover, a co-culture model of macrophages and HNSCC cells was established to investigate whether FN1 induce macrophage M2 polarization. Finally, we used bioinformatic methods to explore the possible FN1-related pathways in HNSCC.

Results

FN1 is significantly overexpressed in HNSCC patients and has been obviously correlated with higher pathological stage and poor prognosis. Downregulation of FN1 suppressed the proliferation, migration and invasion of HNSCC cells, and inhibited macrophage M2 polarization in vitro. In addition, “PI3K-Akt” and “MAPK” signaling pathways may be involved in the malignant process of FN1 in HNSCC.

Conclusion

The overexpression of FN1 promotes HNSCC progression and induces macrophages M2 polarization. FN1 may serve as a promising prognostic biomarker and therapeutic target in HNSCC.

C-C Chemokine Receptor 7 in Cancer

C-C chemokine receptor 7 (CCR7) was one of the first two chemokine receptors that were found to be upregulated in breast cancers. Chemokine receptors promote chemotaxis of cells and tissue organization. Since under homeostatic conditions, CCR7 promotes migration of immune cells to lymph nodes, questions immediately arose regarding the ability of CCR7 to direct migration of cancer cells to lymph nodes. The literature since 2000 was examined to determine to what extent the expression of CCR7 in malignant tumors promoted migration to the lymph nodes. The data indicated that in different cancers, CCR7 plays distinct roles in directing cells to lymph nodes, the skin or to the central nervous system. In certain tumors, it may even serve a protective role. Future studies should focus on defining mechanisms that differentially regulate the unfavorable or beneficial role that CCR7 plays in cancer pathophysiology, to be able to improve outcomes in patients who harbor CCR7-positive cancers.

Does CCL19 act as a double-edged sword in cancer development?

Cancer is considered a life-threatening disease, and several factors are involved in its development. Chemokines are small proteins that physiologically exert pivotal roles in lymphoid and non-lymphoid tissues. The imbalance or dysregulation of chemokines has contributed to the development of several diseases, especially cancer. CCL19 is one of the homeostatic chemokines that is abundantly expressed in the thymus and lymph nodes. This chemokine, which primarily regulates immune cell trafficking, is involved in cancer development. Through the induction of anti-tumor immune responses and inhibition of angiogenesis, CCL19 exerts tumor-suppressive functions. In contrast, CCL19 also acts as a tumor-supportive factor by inducing inflammation, cell growth, and metastasis. Moreover, CCL19 dysregulation in several cancers, including colorectal, breast, pancreatic, and lung cancers, has been considered a tumor biomarker for diagnosis and prognosis. Using CCL19-based therapeutic approaches has also been proposed to overcome cancer development. This review will shed more light on the multifarious function of CCL19 in cancer and elucidate its application in diagnosis, prognosis, and even therapy. It is expected that the study of CCL19 in cancer might be promising to broaden our knowledge of cancer development and might introduce novel approaches in cancer management.

Specificity protein 1/microRNA-92b forms a feedback loop promoting the migration and invasion of head and neck squamous cell carcinoma

In this study we report a novel specificity protein 1 (SP1)/microRNA-92b (miR-92b) feedback loop regulating the migration and invasion of head and neck squamous cell carcinoma (HNSCC). Microarray and real-time Polymerase Chain Reaction (PCR) were used to detect gene expression in HNSCC tissues and cell lines. Transwell migration, invasion, wound healing and cell counting kit - 8 (CCK-8) cell assays were used to compare cell migration, invasion and proliferation abilities. Chromatin Immunoprecipitation (ChIP) assays were used to detect SP1 binding to the miR-92b promoter. Western blot was used to detect protein levels. An in vivo tumorigenesis experiment was used to evaluate the effect of SP1 knockdown on tumor growth and protein levels were evaluated by immunohistochemistry. We found that the miR-92b expression level was elevated in HNSCC primary focus tissue compared with adjacent normal tissue, and a higher level of miR-92b was related to a higher clinical stage and worse prognosis of HNSCC patients. MiR-92b and SP1 mutually promoted each expression and cooperatively facilitated the migration, invasion and proliferation of HNSCC cells. A decreased level of SP1/miR-92b resulted in a restraint of in vivo tumor growth. In conclusion, our results suggest that the SP1/miR-92b feedback loop generally promotes HNSCC invasion and metastasis, thus presenting a possible therapeutic target in the treatment of HNSCC patients.

Therapeutic strategies of different HPV status in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the 9^th most common malignant tumor in the world. Based on the etiology, HNSCC has two main subtypes: human papillomavirus (HPV) -related and HPV-unrelated. HPV-positive HNSCC is more sensitive to treatment with favorable survival. Due to the different biological behaviors, individual therapy is necessary and urgently required to deduce the therapeutic intensity of HPV-positive disease and look for a more effective and toxicity-acceptable regimen for HPV-negative disease. EGFR amplification and PI3K/AKT/mTOR pathway aberrant activation are quite common in HPV-positive HNSCC. Besides, HPV infection alters immune cell infiltrating in HNSCC and encompasses a diverse and heterogeneous landscape with more immune infiltration. On the other hand, the chance of HPV-negative cancers harboring mutation on the P53 gene is significantly higher than that of HPV-positive disease. This review focuses on the updated preclinical and clinical data of HPV-positive and HPV-negative HNSCC and discusses the therapeutic strategies of different HPV status in HNSCC.

HPV infection related immune infiltration gene associated therapeutic strategy and clinical outcome in HNSCC

Background

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common tumor in human. Research has shown that HPV status HNSCC is a unique prognosis factor, which may due to its immune infiltration landscape. But the underlying mechanism is unclear.

Methods

In this study, we used a combination of several bioinformatics tools, including WCGNA, ssGSEA, CIBERSORT, TIDE,etc., to explore significant genes both related to HPV infection status and immune cell infiltration in HNSCC patients.

Results

Combined with several bioinformatics algorithms, eight hub genes were identified, including LTB, CD19, CD3D, SKAP1, KLRB1, CCL19, TBC1D10C and ARHGAP4. In HNSCC population, the hub genes had a stable co-expression, which was related to immune cell infiltration, especially CD8+ T cells, and the infiltrative immune cells were in a dysfunctional status. Samples with high hub genes expression presented with better response to immune check point block (ICB) therapy and sensitivity to bleomycin and methotrexate.

Conclusions

The eight hub genes we found presented with a stable co-expression in immune cell infiltration of HPV + ve HNSCC population. The co-expression of hub genes related to an immune microenvironment featuring an increase in immune cells but high degree of immune dysfunction status. Patients with high hub gene expression had a better response to ICB treatment, bleomycin and methotrexate. The co-expression of hub genes may be related to immune infiltration status in patients. The concrete molecular mechanism of hub genes function demands further exploration.

Hsa-let-7e-5p Inhibits the Proliferation and Metastasis of Head and Neck Squamous Cell Carcinoma Cells by Targeting Chemokine Receptor 7

This study aimed at determining the role of hsa-let-7e-5p in the progression of head and neck squamous cell carcinoma (HNSCC). The relative levels of hsa-let-7e-5p transcripts in 15 paired of HNSCC and adjacent non-tumor tissues and cells were examined by quantitative real-time PCR (qRT-PCR). The potential targets of hsa-let-7e-5p were predicted and validated by luciferase assay. The impact of altered hsa-let-7e-5p expression on HNSCC cell proliferation and metastasis was determined by CCK-8, wound healing, transwell migration and invasion assays. The effect of hsa-let-7e-5p over-expression on the growth of HNSCC was examined in vivo. Hsa-let-7e-5p expression was significantly down-regulated in HNSCC tissues and highly metastatic PCI-37B cells. Bioinformatic analysis predicted that hsa-let-7e-5p bound to the 3'untranslated region (3'UTR) of chemokine receptor 7(CCR7), which was validated by luciferase assay. While transfection with hsa-let-7e-5p mimic significantly decreased CCR7 protein expression, transfection with hsa-let-7e-5p inhibitor increased CCR7 protein expression in HNSCC cells. Similarly, hsa-let-7e-5p over-expression inhibited PCI-37B cell proliferation, wound healing, migration and invasion, while inhibition of endogenous hsa-let-7e-5p had opposite effects in PCI-37A cells. Hsa-let-7e-5p over-expression inhibited PCI-37B tumor growth in vivo. Therefore, hsa-let-7e-5p acts as a tumor suppressor to inhibit the progression of HNSCC by targeting CCR7 expression. Hsa-let-7e-5p and CCR7 may be therapeutic targets of HNSCC.

Predicting miRNA targets for head and neck squamous cell carcinoma using an ensemble method

BACKGROUND

This study aimed to uncover potential microRNA (miRNA) targets in head and neck squamous cell carcinoma (HNSCC) using an ensemble method which combined 3 different methods: Pearson's correlation coefficient (PCC), Lasso and a causal inference method (i.e., intervention calculus when the directed acyclic graph (DAG) is absent [IDA]), based on Borda count election.

METHODS

The Borda count election method was used to integrate the top 100 predicted targets of each miRNA generated by individual methods. Afterwards, to validate the performance ability of our method, we checked the TarBase v6.0, miRecords v2013, miRWalk v2.0 and miRTarBase v4.5 databases to validate predictions for miRNAs. Pathway enrichment analysis of target genes in the top 1,000 miRNA-messenger RNA (mRNA) interactions was conducted to focus on significant KEGG pathways. Finally, we extracted target genes based on occurrence frequency ≥3.

RESULTS

Based on an absolute value of PCC >0.7, we found 33 miRNAs and 288 mRNAs for further analysis. We extracted 10 target genes with predicted frequencies not less than 3. The target gene MYO5C possessed the highest frequency, which was predicted by 7 different miRNAs. Significantly, a total of 8 pathways were identified; the pathways of cytokine-cytokine receptor interaction and chemokine signaling pathway were the most significant.

CONCLUSIONS

We successfully predicted target genes and pathways for HNSCC relying on miRNA expression data, mRNA expression profile, an ensemble method and pathway information. Our results may offer new information for the diagnosis and estimation of the prognosis of HNSCC.

[Stromal cell-derived factor-1 inducing metastasis squamous cell carcinoma of head and neck induced via integrin ανβ3-CXC chemokine receptor 4/7 biological axis]

OBJECTIVE

To observe the influence of LM609/AMD3100/CCX754 on chemotactic capability, cytoskeleton, and expression of integrin ανβ3 protein of squamous cell carcinoma of head and neck (SCCHN) cell line PCI-13 induced by stromal cell-derived factor-1 (SDF-1) in vitro.

METHODS

Migration assays, flow cytometry and immunofluorescence were used to observe the effects of SDF-1, LM609, AMD3100 and CCX754 on the migration, cytoskeleton and the expression of integrin ανβ3 protein in PCI-13 cell lines.

RESULTS

SDF-1 favored PCI-13 cell migration, pseudopod formation, and activities of integrin ανβ3 phosphorylation. LM609, AMD3100, and CCX754 blocked all these effects.

CONCLUSIONS

SDF-1 can induce metastatic SCCHN by integrin ανβ3-CXC chemokine receptor (CXCR) 4/CXCR7 axi. LM609, AMD3100, and CCX754 and can reduce the regulation of SDF-1 on SCCHN activity.

The role of Pyk2 in the CCR7-mediated regulation of metastasis and viability in squamous cell carcinoma of the head and neck cells in vivo and in vitro

In the present study, we aimed to demonstrate whether praline-rich tyrosine kinase-2 (Pyk2) participates in the chemokine receptor 7 (CCR7) downstream signaling network, and to determine the role of this molecule and the related mechanism in the CCR7-mediated regulation of viability and metastasis in vivo and in vitro of squamous cell carcinoma of the head and neck (SCCHN). We constructed the stable Pyk2 related non-kinase (PRNK)-expressing SCCHN cell line, and examined the viability, apoptosis, migration, invasion and adhesion ability in the transfected and untransfected SCCHN cells. An SCCHN tumor model in nude mice was designed and the tumor growth rate was assayed. E-cadherin and vimentin expression was assessed when Pyk2 was inactivated. We found that the stable PRNK-expressing SCCHN cells exhibited low viability, a high rate of apoptosis, low migratory ability, low invasive ability and low adhesion capacity. In the nude mouse body, the tumors formed by these cells grew slowly when compared to the tumor growth in the control group. When Pyk2 was inactivated, CCR7-induced E-cadherin and vimentin expression levels were altered. Thus, Pyk2 is a key downstream signaling molecules of CCR7 in SCCHN, which promotes SCCHN tumorigenesis and progression.

The role of CCL21/CCR7 chemokine axis in breast cancer-induced lymphangiogenesis

Background

Tumor-induced lymphangiogenesis facilitates breast cancer progression by generating new lymphatic vessels that serve as conduits for tumor dissemination to lymph nodes and beyond. Given the recent evidence suggesting the implication of C-C chemokine ligand 21/chemokine receptor 7 (CCL21/CCR7) in lymph node metastasis, the aim of our study was to define the role of this chemokine pair in breast cancer-associated lymphangiogenesis.

Methods

The expression analysis of CCL21/CCR7 pair and lymphatic endothelial cell (LEC) markers in breast cancer specimens was performed by means of quantitative real-time PCR. By utilizing CCR7 and CCL21 gene manipulated breast cancer cell implants into orthotopic sites of nude mice, lymphatic vessel formation was assessed through quantitative real-time PCR, immunohistochemistry and immunofluorescence assays. Finally, the lymphangiogenic potential of CCL21/CCR7 was assessed in vitro with primary LECs through separate functional assays, each attempting to mimic different stages of the lymphangiogenic process.

Results

We found that CCR7 mRNA expression in human breast cancer tissues positively correlates with the expression of lymphatic endothelial markers LYVE-1, podoplanin, Prox-1, and vascular endothelial growth factor-C (VEGF-C). We demonstrated that the expression of CCL21/CCR7 by breast cancer cells has the ability to promote tumor-induced lymph-vascular recruitment in vivo. In vitro, CCL21/CCR7 chemokine axis regulates the expression and secretion of lymphangiogenic factor VEGF-C and thereby promotes proliferation, migration, as well as tube formation of the primary human LECs. Finally, we showed that protein kinase B (AKT) signaling pathway is the intracellular mechanism of CCR7-mediated VEGF-C secretion by human breast cancer cells.

Conclusions

These results reveal that CCR7 and VEGF-C display a significant crosstalk and suggest a novel role of the CCL21/CCR7 chemokine axis in the promotion of breast cancer-induced lymphangiogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0306-4) contains supplementary material, which is available to authorized users.

Chemokine receptor 7 promotes tumor migration and invasiveness via the RhoA/ROCK pathway in metastatic squamous cell carcinoma of the head and neck

Metastatic squamous cell carcinoma of the head and neck (SCCHN) has been shown to express chemokine receptor 7 (CCR7), which can activate signaling pathways to promote invasion and survival of SCCHN cells. We hypothesized that the RhoA/Rho-associated kinase (ROCK) pathway is involved in the CCR7-induced invasion and migration of metastatic SCCHN cells. Thus, using migration, matrigel invasion and scrape wound-healing assays, we elucidated the role of RhoA in mediating CCR7-associated cellular mobility. Pull-down assays and western blotting were used to measure RhoA and its downstream expression. Immunohistochemical staining and analysis were useful in identifying the correlation between CCR7 and RhoA expression and clinicopathological factors. The results showed that inhibition of RhoA/ROCK reduced the tumor cell migration and invasiveness induced by CCL19. Activated RhoA, proline-rich tyrosine kinase-2 (Pyk2) and cofilin induced by CCL19 were elevated, and increased RhoA, Pyk2 and cofilin activity was eliminated by CCR7mAb, RhoA/ROCK and Pyk2 inhibitors, indicating involvement of the RhoA/ROCK-Pyk2-cofilin cascade. In summary, CCR7 via RhoA/ROCK-Pyk2 cofilin pathway promotes invasion and migration of metastatic SCCHN cells.

CCR7 regulates cell migration and invasion through JAK2/STAT3 in metastatic squamous cell carcinoma of the head and neck

Squamous cell carcinoma of the head and neck (SCCHN) frequently involves metastasis at diagnosis. Our previous research has demonstrated that CCR7 plays a key role in regulating SCCHN metastasis, and this process involves several molecules, such as PI3K/cdc42, pyk2, and Src. In this study, the goals are to identify whether JAK2/STAT3 also participates in CCR7's signal network, its relationship with other signal pathways, and its role in SCCHN cell invasion and migration. The results showed that stimulation of CCL19 could induce JAK2/STAT3 phosphorylation, which can be blocked by Src and pyk2 inhibitors. After activation, STAT3 was able to promote low expression of E-cadherin and had no effect on vimentin. This JAk2/STAT3 pathway not only mediated CCR7-induced cell migration but also mediated invasion speed. The immunohistochemistry results also showed that the phosphorylation of STAT3 was correlated with CCR7 expression in SCCHN, and CCR7 and STAT3 phosphorylation were all associated with lymph node metastasis. In conclusion, JAk2/STAT3 plays a key role in CCR7 regulating SCCHN metastasis.

CCR7 regulates cell migration and invasion through MAPKs in metastatic squamous cell carcinoma of head and neck

Migration and invasion of tumor cells are essential prerequisites for the formation of metastasis in malignant diseases. Previously, we have reported that CC chemokine receptor 7 (CCR7) regulates the mobility of squamous cell carcinoma of head and neck (SCCHN) cells through several pathways, such as integrin and cdc42. In this study, we investigated the connection between CCR7 and mitogen-activated protein kinase (MAPK) family members, and their influence on cell invasion and migration in metastatic SCCHN cells. Western blotting, immunostaining and fluorescence microcopy were used to detect the protein expression and distribution of MAPKs, and the Migration assay, Matrigel invasion assay and wound-healing assay to detect the role of MAPKs in CCR7 regulating cell mobility. To analyze the correlation between CCR7 and MAPK activity and clinicopathological factors immunohistochemical staining was emplyed. The results showed stimulation of CCL19 and the activation of CCR7 could induce ERK1/2 and JNK phosphorylation, while it had no efect on p38. After activation, ERK1/2 and JNK promoted E-cadherin low expression and Vimentin high expression. The MAPK pathway not only mediated CCR7 induced cell migration, but also mediated invasion speed. The immunohistochemistry results showed that CCR7 was correlated with the phosphorylation of ERK1/2 and JNK in SCCHN, and these molecules were all associated with lymph node metastasis. Therefore, our study demonstrates that MAPK members (ERK1/2 and JNK) play a key role in CCR7 regulating SCCHN metastasis.

Pediatric adrenocortical tumors: diagnosis, management and advancements in the understanding of the genetic basis and therapeutic implications

Adrenocortical tumors (ACTs) may be sporadic or related to inherited genetic syndromes. Uncovering the molecular defects underlying these genetic syndromes has revealed key signaling pathways involved in adrenocortical tumorigenesis. Although the understanding of ACT biology has improved, to date, very few potential prognostic molecular markers of childhood ACTs have been identified. In this review, we summarize the current knowledge of the epidemiology, clinical presentation, diagnosis, prognosis and treatment options for pediatric patients with ACTs. A review of the genetic basis of adrenocortical tumorigenesis is presented, focusing on the main molecular abnormalities involved in the tumorigenic process and potential novel therapy targets that have been generated, or are being generated, with the discovery of these molecular defects.

Chemokine receptor 7 enhances cell chemotaxis and migration of metastatic squamous cell carcinoma of head and neck through activation of matrix metalloproteinase-9

The mechanisms leading to squamous cell carcinoma of head and neck (SCCHN) metastasis are not fully understood. Although evidence shows that the chemokine receptor 7 (CCR7) and its ligand CCL19 may regulate tumor dissemination, their role is not clearly defined in SCCHN. Matrix metalloproteinases break consisting of tissue barrier to the surrounding tissue invasion and metastasis by destroying the balance of matrix degradation of the basement membrane of tumor cells and extracellular matrix (ECM). We used chemotaxis and migration assays, western blotting, gelatin zymography, actin polymerization assay, immunofluorescence staining and immunohistochemical analysis to explore whether MMP-9 can be activated by CCL19 (CCR7's ligand) and its role in SCCHN. The experiments were performed in the metastatic SCCHN cell line PCI-37B after pre-incubation of the cells with CCL19 and SB-3CT (inhibitor of MMP-9). Our results demonstrated that CCR7 favors PCI-37B cell chemotaxis and migration, upregulation of MMP-9 protein and motivates the activity of MMP-9 protein, induces reorganization of the actin cytoskeleton and upregulation of MMP-9 protein. SB-3CT can block all these effects. Collectively, our data indicated that CCR7 regulates cell chemotaxis and migration via MMP-9 in metastatic SCCHN, and these results provide a basis for new strategies in preventing metastases of SCCHN.

CCR7 expression correlates with subcutaneous involvement in mycosis fungoides skin lesions and promotes migration of mycosis fungoides cells (MyLa) through mTOR activation

BACKGROUND

The molecular pathogenesis of mycosis fungoides (MF) is currently poorly understood. The chemokine receptor CCR7 has been demonstrated to be involved in the development and progression of certain cancers, but its role in MF has rarely been investigated.

OBJECTIVES

We seek to determine whether CCR7 is expressed in MF skin lesions. In addition, we evaluate whether CCR7 plays a role in MF cell proliferation and migration, and which signaling pathways are involved.

METHODS

Immunohistochemical staining of 21 cases of MF pathology specimens with CCR7 was performed. Medical charts and pathology slides of these cases were reviewed. Surface expression of CCR7 on MyLa cells (MF cell line) and peripheral blood mononuclear cells (PBMCs) was assessed by flow cytometry. Cell proliferation and migration were evaluated with the Alamar Blue assay and transwell chemotaxis assay, respectively.

RESULTS

CCR7 was found to be expressed in 62% (13 out of 21) of MF pathology specimens, and its expression correlated with subcutaneous extension of lymphoma cells. CCR7 expression was increased on the surface of MyLa cells compared to that on PBMCs. Addition of CCL21 (CCR7 agonist) enhanced MyLa cell migration but not proliferation. The CCL21-induced MyLa cell migration was found to be mediated by the mTOR pathway.

CONCLUSIONS

CCR7 is more likely to be expressed in MF skin lesions with subcutaneous involvement. Activation of CCR7 promotes migration of MyLa cells (MF cell line) through the mTOR pathway. These findings provide new insights into the significance of CCR7 in the pathophysiology of MF.

Full length articles published in BJOMS during 2010-11--an analysis by sub-specialty and study type

Full length articles such as prospective and retrospective studies, case series, laboratory-based research and reviews form the majority of papers published in the British Journal of Oral and Maxillofacial Surgery (BJOMS). We were interested to evaluate the breakdown of these types of articles both by sub-specialty and the type of study as well as the proportion that are written by UK colleagues compared to overseas authors over a 2 year period (2010-11). A total of 191 full length articles across all sub-specialties of our discipline were published, with 107 papers (56%) coming from UK authors. There were proportionately more oncology papers arising from the UK than overseas (60 and 30% of total respectively) while the opposite was found for cleft/deformity studies (10% and 22%). There was only one laboratory-based study published from the UK compared with 27 papers from overseas. The number of quality papers being submitted to the Journal continues to increase, and the type of article being published between UK and overseas probably reflects different practices and case-loads amongst colleagues. The relatively few UK laboratory based studies published in BJOMS compared to overseas authors are most likely due to authors seeking the most prestigious journals possible for their work.

CCL21/CCR7 prevents apoptosis via the ERK pathway in human non-small cell lung cancer cells

Previously, we confirmed that C-C chemokine receptor 7 (CCR7) promotes cell proliferation via the extracellular signal-regulated kinase (ERK) pathway, but its role in apoptosis of non-small cell lung cancer (NSCLC) cell lines remains unknown. A549 and H460 cells of NSCLC were used to examine the effect of CCL21/CCR7 on apoptosis using flow cytometry. The results showed that activation of CCR7 by its specific ligand, exogenous chemokine ligand 21 (CCL21), was associated with a significant decline in the percent of apoptosis. Western blot and real-time PCR assays indicated that activation of CCR7 significantly caused upregulation of anti-apoptotic bcl-2 and downregulation of pro-apoptotic bax and caspase-3, but not p53, at both protein and mRNA levels. CCR7 small interfering RNA significantly attenuated these effects of exogenous CCL21. Besides, PD98059, a selective inhibitor of MEK that disrupts the activation of downstream ERK, significantly abolished these effects of CCL21/CCR7. Coimmunoprecipitation further confirmed that there was an interaction between p-ERK and bcl-2, bax, or caspase-3, particularly in the presence of CCL21. These results strongly suggest that CCL21/CCR7 prevents apoptosis by upregulating the expression of bcl-2 and by downregulating the expression of bax and caspase-3 potentially via the ERK pathway in A549 and H460 cells of NSCLC.

What are we reading? A study of downloaded and cited articles from the British Journal of Oral and Maxillofacial Surgery in 2010

A large number of papers related to oral and maxillofacial surgery are published in many specialist journals. With the ever-increasing use of the internet it is easy to download them as part of a journal subscription on a fee per paper basis, or in some cases for free. Online access to the British Journal of Oral and Maxillofacial Surgery (BJOMS) is free to British Association (BAOMS) members with a $30 fee per paper download for non-members. Many colleagues use the online version of the journal, and this provides valuable information about downloading trends. Other data on articles that have been cited in subsequent publications are also readily available, and they form the basis for the calculation of a journal's impact factor. We evaluated the top 50 downloaded papers from the BJOMS website in 2010 to ascertain which articles were being read online. We also obtained data on the number of citations for papers published in 2009-2010 to see whether these papers were similar to the articles being downloaded. In 2010 there were over 360000 downloaded articles. The most popular papers were leading articles, reviews, and full length articles; only one short communication featured in the top 50 downloads. The papers most cited in subsequent publications were full length articles and leading articles or reviews, which represent 80% of the total citations of the 50 papers. Ten papers were in both the top 50 downloaded and most cited lists. We discuss the implications of this study for the journal and our readers.

Mammalian target of rapamycin expression and laryngeal squamous cell carcinoma prognosis: novel preliminary evidence

AIMS

The mammalian target of rapamycin (mTOR) has a key role in regulating cancer cell proliferation, apoptosis, cell migration, and angiogenesis. The aim of this study was to assess the relationships between mTOR and clinicopathological and prognostic parameters in laryngeal squamous cell carcinoma (SCC).

METHODS AND RESULTS

Mammalian target of rapamycin expression was determined in 103 consecutive operable laryngeal SCCs. Among the mTOR-positive cases, the locoregional recurrence rate was higher (P=0.048) and the disease-free survival (DFS) rate was shorter (P=0.031) in patients with mTOR expression >50.7%. In the N(0) subgroup, the disease recurrence rate was higher (P=0.034) and the DFS was shorter (P=0.009) in patients with mTOR expression >50.7%. In mTOR-positive patients, multivariate analysis showed that N stage (P=0.0001) and mTOR status (P=0.042) were independent indicators of a poor prognosis.

CONCLUSIONS

mTOR appeared to be a significant predictor of DFS in univariate and multivariate models. mTOR expression in laryngeal SCC may be useful for the detection of patients at higher risk for recurrence, and N(0) patients at higher risk for early locoregional recurrence who might benefit from more aggressive therapy. The role of mTOR inhibitors in multimodality or multitarget strategies against laryngeal SCC warrants investigation.

Akt/mTOR counteract the antitumor activities of cixutumumab, an anti-insulin-like growth factor I receptor monoclonal antibody

Recent reports have shown limited anticancer therapeutic efficacy of insulin-like growth factor receptor (IGF-1R)-targeted monoclonal antibodies (mAb), but the resistance mechanisms have not been completely identified. Because cooperation between epidermal growth factor receptor (EGFR) and IGF-IR could cause resistance to inhibitors of individual receptor tyrosine kinases, we investigated the involvement of EGFR signaling in resistance to IGF-1R mAb and the underlying mechanisms of action. Most head and neck squamous cell carcinoma (HNSCC) tissues had coexpression of total and phosphorylated IGF-1R and EGFR at high levels compared with paired adjacent normal tissues. Treatment with cixutumumab (IMC-A12), a fully humanized IgG1 mAb, induced activation of Akt and mTOR, resulting in de novo synthesis of EGFR, Akt1, and survivin proteins and activation of the EGFR pathway in cixutumumab-resistant HNSCC and non-small cell lung cancer (NSCLC) cells. Targeting mTOR and EGFR pathways by treatment with rapamycin and cetuximab (an anti-EGFR mAb), respectively, prevented cixutumumab-induced expression of EGFR, Akt, and survivin and induced synergistic antitumor effects in vitro and in vivo. These data show that resistance to IGF-1R inhibition by mAbs is associated with Akt/mTOR-directed enhanced synthesis of EGFR, Akt1, and survivin. Our findings suggest that Akt/mTOR might be effective targets to overcome the resistance to IGF-1R mAbs in HNSCC and NSCLC.

CCL21/CCR7 promotes G2/M phase progression via the ERK pathway in human non-small cell lung cancer cells

C-C chemokine receptor 7 (CCR7) contributes to the survival of certain cancer cell lines, but its role in the proliferation of human non-small cell lung cancer (NSCLC) cells remains vague. Proliferation assays performed on A549 and H460 NSCLC cells using Cell Counting Kit-8 indicated that activation of CCR7 by its specific ligand, exogenous chemokine ligand 21 (CCL21), was associated with a significant linear increase in cell proliferation with duration of exposure to CCL21. The CCL21/CCR7 interaction significantly increased the fraction of cells in the G₂/M phase of the cell cycle as measured by flow cytometry. In contrast, CCL21/CCR7 had no significant influence on the G₀/G₁ and S phases. Western blot and real-time PCR indicated that CCL21/CCR7 significantly upregulated expression of cyclin A, cyclin B1, and cyclin-dependent kinase 1 (CDK1), which are related to the G₂/M phase transition. The expression of cyclin D1 and cyclin E, which are related to the G₀/G₁ and G₁/S transitions, was not altered. The CCL21/CCR7 interaction significantly enhanced phosphorylation of extracellular signal-regulated kinase (P-ERK) but not Akt, as measured by Western blot. LY294002, a selective inhibitor of PI3K that prevents activation of the downstream Akt, did not weaken the effect of CCL21/CCR7 on P-ERK. Coimmunoprecipitation further confirmed that there was an interaction between P-ERK and cyclin A, cyclin B1, or CDK1, particularly in the presence of CCL21. CCR7 small interfering RNA or PD98059, a selective inhibitor of MEK that disrupts the activation of downstream ERK, significantly abolished the effects of exogenous CCL21. These results suggest that CCL21/CCR7 contributes to the time-dependent proliferation of human NSCLC cells by upregulating cyclin A, cyclin B1, and CDK1 potentially via the ERK pathway.

Inhibition of PI3K/mTOR pathways in glioblastoma and implications for combination therapy with temozolomide

Due to its molecular heterogeneity and infiltrative nature, glioblastoma multiforme (GBM) is notoriously resistant to traditional and experimental therapeutics. To overcome these hurdles, targeted agents have been combined with conventional therapy. We evaluated the preclinical potential of a novel, orally bioavailable PI3K/mTOR dual inhibitor (XL765) in in vitro and in vivo studies. In vivo serially passaged human GBM xenografts that are more genetically stable than GBM cell lines in culture were used for all experiments. Biochemical downstream changes were evaluated by immunoblot and cytotoxicity by colorimetric ATP-based assay. For in vivo experiments, human xenograft GBM 39 grown intracranially in nude mice was altered to express luciferase to monitor tumor burden by optical imaging. XL765 resulted in concentration-dependent decreases in cell viability in vitro. Cytotoxic doses resulted in specific inhibition of PI3K signaling. Combining XL765 with temozolomide (TMZ) resulted in additive toxicity in 4 of 5 xenografts. In vivo, XL765 administered by oral gavage resulted in greater than 12-fold reduction in median tumor bioluminescence compared with control (Mann-Whitney test p = 0.001) and improvement in median survival (logrank p = 0.05). TMZ alone showed a 30-fold decrease in median bioluminescence, but the combination XL765 + TMZ yielded a 140-fold reduction in median bioluminescence (Mann-Whitney test p = 0.05) with a trend toward improvement in median survival (logrank p = 0.09) compared with TMZ alone. XL765 shows activity as monotherapy and in combination with conventional therapeutics in a range of genetically diverse GBM xenografts.

Selective abrogation of BiP/GRP78 blunts activation of NF-κB through the ATF6 branch of the UPR: involvement of C/EBPβ and mTOR-dependent dephosphorylation of Akt

Subtilase cytotoxin (SubAB) that selectively cleaves BiP/GRP78 triggers the unfolded protein response (UPR) and protects mice from endotoxic lethality and collagen arthritis. We found that pretreatment of cells with SubAB suppressed tumor necrosis alpha (TNF-α)-induced activation of NF-κB and NF-κB-dependent chemokine expression. To elucidate underlying mechanisms, the involvement of C/EBP and Akt, putative regulators of NF-κB, was investigated. Among members of the C/EBP family, SubAB preferentially induced C/EBPβ. Overexpression of C/EBPβ suppressed TNF-α-induced NF-κB activation, and knockdown of C/EBPβ attenuated the suppressive effect of SubAB on NF-κB. We identified that the ATF6 branch of the UPR plays a crucial role in the induction of C/EBPβ. In addition to this effect, SubAB depressed basal and TNF-α-induced phosphorylation of Akt via the UPR. It was mediated by the induction of ATF6 and consequent activation of mTOR that dephosphorylated Akt. Inhibition of Akt attenuated activation of NF-κB by TNF-α, suggesting that the mTOR-Akt pathway is another target for SubAB-initiated, UPR-mediated NF-κB suppression. These results elucidated that SubAB blunts activation of NF-κB through ATF6-dependent mechanisms, i.e., preferential induction of C/EBPβ and mTOR-dependent dephosphorylation of Akt.

Chemopreventive potential of natural compounds in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is one of the most fatal cancers worldwide. Despite advances in the management of HNSCC, the overall survival for patients has not improved significantly due to advanced stages at diagnosis, high recurrence rate after surgical removal, and second primary tumor development, which underscore the importance of novel strategies for cancer prevention. Cancer chemoprevention, the use of natural or synthetic compounds to prevent, arrest, or reverse the process of carcinogenesis at its earliest stages, aims to reverse premalignancies and prevent second primary tumors. Genomics and proteomics information including initial mutation, cancer promotion, progression, and susceptibility has brought molecularly targeted therapies for drug development. The development of preventive approaches using specific natural or synthetic compounds, or both, requires a depth of understanding of the cross-talk between cancer signaling pathways and networks to retain or enhance chemopreventive activity while reducing known toxic effects. Many natural dietary compounds have been identified with multiple molecular targets, effective in the prevention and treatment of cancer. This review describes recent advances in the understanding of the complex signaling networks driving cancer progression and of molecularly targeted natural compounds under preclinical and clinical investigation.