Immunohistochemical expression of CD44s in human neuroblastic tumors: Moroccan experience and highlights on current data

Pediatric solid tumors in Africa: different biology?

PURPOSE OF REVIEW

To review the recent literature regarding biologic characteristics of pediatric solid tumors in African children.

RECENT FINDINGS

Data regarding pediatric solid tumors in Africa, while increasing, remain sparse when considering the ethnic and geographic diversity of the continent. Recent work, especially regarding nephroblastoma in Kenya, has identified some biologic variability among local tribes but also when compared with North American tumors. In general, reports from across the continent reveal markedly poorer survival for pediatric patients with solid tumors when compared with high-resourced regions.

SUMMARY

Multiple resource-related and infrastructure-related challenges contribute to poorer outcomes, and these require systematic, multidisciplinary, and structured solutions. Socioeconomic factors and limited access to care currently seem to drive the survival outcomes in children with solid cancers in Africa.

NF-κB signaling pathway confers neuroblastoma cells migration and invasion ability via the regulation of CXCR4

Background

Accumulating evidence implicates the transcription factor NF-κB as a positive mediator of tumor metastasis, but the molecular mechanism(s) involved in this process remains largely unknown. In this study, we investigated the role of NF-κB signaling pathway in the regulation of CXC chemokine receptor-4 (CXCR4) in neuroblastoma metastasis.

Material/Methods

NF-κB, CXCR4 mRNA and protein expression were measured by RT-PCR, and Western blot. Tumor necrosis factor-a (TNF-α) was used to induce the upregulation of NF-κB and CXCR4. The knockdown of NF-κB and CXCR4 was achieved by PDTC. Transwell assay was used to investigate the role of NF-κB (P65) in neuroblastoma cell migration and invasion. An in vitro co-culture system was established to investigate the role of tumor microenvironment in regulation of the NF-κB signaling pathway.

Results

Over-expression of NF-κB (p65) promoted tumor migration and invasion through the upregulation of CXCR4; however, knockdown of NF-κB(P65) inhibited tumor migration and invasion through blocking the expression of CXCR4. Consistently, in the co-culture system, the expression of CXCR4 was partly dependent on the expression of NF-κB (p65).

Conclusions

Our studies reveal critical roles for the NF-κB signaling pathway in neuroblastoma migration and invasion. The mechanism may be through up-regulation of CXCR4, mediated by the NF-κB signaling pathways. Targeting NF-κB signalling pathways and ultimately CXCR4 could be a strategy in neuroblastoma therapy.

Involvement of the nuclear factor-κB signaling pathway in the regulation of CXC chemokine receptor-4 expression in neuroblastoma cells induced by tumor necrosis factor-α

Metastasis is a hallmark of malignant neuroblastoma and is the main reason for therapeutic failure and recurrence of the tumor. The CXC chemokine receptor-4 (CXCR4), a Gi protein-coupled receptor for the ligand CXCL12/stromal cell-derived factor-1α (SDF-1α), is expressed in various types of tumor. This receptor mediates the homing of tumor cells to specific organs that express the ligand, CXCL12, for this receptor and plays an important role in tumor growth, invasion, metastasis and angiogenesis. In the present study, the inflammatory cytokine, tumor necrosis factor‑α (TNF‑α) upregulated CXCR4 expression in neuroblastoma cells and increased migration to the CXCR4 ligand SDF‑1α. In addition, this effect was dependent upon NF-κB transcriptional activity, as blocking the NF-κB pathway with pyrrolidinedithiocarbamic acid ammonium salt suppressed TNF-α‑induced upregulation of CXCR4 expression and reduced the migration towards the CXCR4 ligand, SDF-1α. Treating neuroblastoma cells with TNF-α resulted in the activation of nuclear factor-kappa B (NF-κB) and subsequently, the translocation of NF-κB from the cytoplasm to the nucleus. Using immunohistochemistry, NF‑κB and CXCR4 were significantly correlated with each other (P=0.0052, Fisher's exact test) in a cohort of neuroblastoma samples (n=80). The present study indicates that the inflammatory cytokine, TNF-α, partially functions through the NF‑κB signaling pathway to upregulate CXCR4 expression to foster neuroblastoma cell metastasis. These findings indicate that effective inhibition of neuroblastoma metastasis should be directed against the inflammatory cytokine-induced NF‑κB/CXCR4/SDF‑1α signaling pathway.

Transforming growth factor-β-induced miR‑143 expression in regulation of non-small cell lung cancer cell viability and invasion capacity in vitro and in vivo

Altered expression of miRNAs contributes to development and progression of non-small cell lung cancer (NSCLC), while transforming growth factor-β (TGF-β) promotes NSCLC cell epithelial-mesenchymal transition. This study aimed to investigate the effects of TGF-β-induced miR‑143 expression in regulation of NSCLC cell viability, invasion capacity in vitro, and xenograft formation and growth in nude mice. NSCLC A549 cells treated with TGF-β were subjected to miRNA microarray analysis and miR‑143 was selected for further study of tumor cell viability, wound healing, invasion capacity in vitro, and tumor growth in nude mice. TGF-β treatment upregulated expression of 16 miRNAs and downregulated expression of 42 miRNAs in A549 cells. qRT-PCR and in situ hybridization data showed that miR‑143 was significantly downregulated in 24 NSCLC and lymph node metastatic tumor tissues, but upregulated by TGF-β treatment in A549 cells. In vitro experiments showed that miR‑143 expression could significantly suppress NSCLC cell viability and invasion capacity, and nude mouse experiments confirmed the in vitro data. Bioinformatic data predicted that Smad3, CD44 and K-Ras were the targeting genes of miR‑143. TGF-β-induced miR‑143 expression was associated with suppressed expression of Smad3, CD44, and K-Ras. This study sheds light on the role of TGF-β in upregulation of miR‑143 and the role of miR‑143 in NSCLC progression, indicating that the target of miR‑143 expression could be further studied as a novel therapeutic strategy for future control of NSCLC.

Atypical esthesioneuroblastoma invading oral cavity: a case report and review of the literature

Esthesioneuroblastoma is an uncommon tumour of neuroectodermal origin. The authors describe a rare presentation of an atypical esthesioneuroblastoma invading oral cavity. The clinical presentation, aetiology, diagnosis, and management of this condition are discussed. The patient developed significant swelling in the right anterosuperior alveolar mucosa and had moderate tooth mobility. Conventional x-rays and computed tomography revealed a large osteolytic lesion, with imprecise limits. Histological findings along with immunohistochemical staining results and clinical features led to the diagnosis of high-grade esthesioneuroblastoma. Local recurrences and neck metastasis were detected. The rare oral findings produced delayed in diagnosis which may lead to a compromise in planning and execution of further radical management and thus a poor prognosis.