Inhibition of the Numb/Notch signaling pathway increases radiation sensitivity in human nasopharyngeal carcinoma cells

Numb/Notch/PLK1 signaling pathway mediated hyperglycemic memory in pancreatic cancer cell radioresistance and the therapeutic effects of metformin

BACKGROUND

Diabetes mellitus has presented a positive role in the progression of pancreatic cancer and "Hyperglycemic memory" could be an important cause for diabetic damage. While limited information is available regarding the role of "hyperglycemic memory" in the pancreatic cancer and its radio-resistance. We therefore investigated correlation among hyperglycemic memory, Numb and metformin in pancreatic cancer radio-resistance.

METHODS

High glucose and hyperglycemic memory models were established in vitro and in vivo. Western blot, real-time PCR were accordingly used to detect Numb /Notch/ Polo-like kinase1 (PLK1) signaling at the level of molecular, cellular and experimental animal model, respectively. The apoptosis rate was evaluated by TUNEL assay and Capase-3 activity. The therapeutic effect of metformin was revealed by detecting the level of Numb / Notch /PLK1 through Western blot and real-time PCR.

RESULTS

Inactivation of Numb promotes the pancreatic cancer radio-resistance through hyperglycemic memory and metformin could suppress the radio-resistance by activating Numb in vitro and in vivo. In addition, PLK1 and Notch signaling pathway (Notch1, HEY1) elevated in pancreatic cancer radio-resistance condition, which was induced by hyperglycemic memory. Moreover, Numb overexpression or metformin could suppress Notch pathway to alleviate pancreatic cancer radio-resistance.

CONCLUSIONS

Our data demonstrated that Numb might be a promising target for the improvement of hyperglycemic memory damage and the effect of metformin deserved urgent attention on pancreatic cancer radio-resistance therapy.

Histone demethylase KDM4A plays an oncogenic role in nasopharyngeal carcinoma by promoting cell migration and invasion

Compelling evidence has indicated the vital role of lysine-specific demethylase 4 A (KDM4A), hypoxia-inducible factor-1α (HIF1α) and the mechanistic target of rapamycin (mTOR) signaling pathway in nasopharyngeal carcinoma (NPC). Therefore, we aimed to investigate whether KDM4A affects NPC progression by regulating the HIF1α/DDIT4/mTOR signaling pathway. First, NPC and adjacent tissue samples were collected, and KDM4A protein expression was examined by immunohistochemistry. Then, the interactions among KDM4A, HIF1α and DDIT4 were assessed. Gain- and loss-of-function approaches were used to alter KDM4A, HIF1α and DDIT4 expression in NPC cells. The mechanism of KDM4A in NPC was evaluated both in vivo and in vitro via RT-qPCR, Western blot analysis, MTT assay, Transwell assay, flow cytometry and tumor formation experiments. KDM4A, HIF1α, and DDIT4 were highly expressed in NPC tissues and cells. Mechanistically, KDM4A inhibited the enrichment of histone H3 lysine 9 trimethylation (H3K9me3) in the HIF1α promoter region and thus inhibited the methylation of HIF1α to promote HIF1α expression, thus upregulating DDIT4 and activating the mTOR signaling pathway. Overexpression of KDM4A, HIF1α, or DDIT4 or activation of the mTOR signaling pathway promoted SUNE1 cell proliferation, migration, and invasion but inhibited apoptosis. KDM4A silencing blocked the mTOR signaling pathway by inhibiting the HIF1α/DDIT4 axis to inhibit the growth of SUNE1 cells in vivo. Collectively, KDM4A silencing could inhibit NPC progression by blocking the activation of the HIF1α/DDIT4/mTOR signaling pathway by increasing H3K9me3, highlighting a promising therapeutic target for NPC.

Tumour heterogeneity and intercellular networks of nasopharyngeal carcinoma at single cell resolution

The heterogeneous nature of tumour microenvironment (TME) underlying diverse treatment responses remains unclear in nasopharyngeal carcinoma (NPC). Here, we profile 176,447 cells from 10 NPC tumour-blood pairs, using single-cell transcriptome coupled with T cell receptor sequencing. Our analyses reveal 53 cell subtypes, including tumour-infiltrating CD8+ T, regulatory T (Treg), and dendritic cells (DCs), as well as malignant cells with different Epstein-Barr virus infection status. Trajectory analyses reveal exhausted CD8+ T and immune-suppressive TNFRSF4+ Treg cells in tumours might derive from peripheral CX3CR1+CD8+ T and naïve Treg cells, respectively. Moreover, we identify immune-regulatory and tolerogenic LAMP3+ DCs. Noteworthily, we observe intensive inter-cell interactions among LAMP3+ DCs, Treg, exhausted CD8+ T, and malignant cells, suggesting potential cross-talks to foster an immune-suppressive niche for the TME. Collectively, our study uncovers the heterogeneity and interacting molecules of the TME in NPC at single-cell resolution, which provide insights into the mechanisms underlying NPC progression and the development of precise therapies for NPC.

FOXA1 Expression in Nasopharyngeal Carcinoma: Association with Clinicopathological Characteristics and EMT Markers

The forkhead box (FOXA) family of transcription factors regulates gene expression and chromatin structure during tumorigenesis and embryonic development. Until now, the relationship between FOXA1 and the nasopharyngeal carcinoma (NPC) has not yet been reported. Therefore, our purpose is to analyze the expression of FOXA1 in 56 NPC patients compared to 10 normal nasopharyngeal mucosae and to correlate the expression with the clinicopathological features. Besides, we investigated the association between FOXA1 and LMP1 gene expression, as well as the EMT markers namely the E-cadherin and Twist1. Among 56 NPC tissues, 34 (60.7%) cases were positive for FOXA1. Furthermore, we noticed that FOXA1 expression correlated with TNM (p = 0.037), and age at diagnosis (p = 0.05). Moreover, positive expression of FOXA1 is likely to be associated with prolonged disease-free survival and overall survival rates. On the other hand, we observed a positive association between the expression of E-cadherin and FOXA1 (p = 0.0051) whereas Twist1 correlated negatively with FOXA1 (p = 0.004). Furthermore, knowing that LMP1 plays a key role in the pathogenesis of NPC, we explored the association of FOXA1 with the LMP1 gene expression in both NPC cell lines and tissues. We found that, in the C666-1 which displays low levels of LMP1, the expression of FOXA1 is high, and inversely in the C15 cell line that expresses a high level of LMP1, the level of FOXA1 is low. Besides, in accordance to our results, we found that in NPC tissues there is a negative association between LMP1 and FOXA1. In conclusion, our results suggest that the overexpression of FOXA1 is associated with a nonaggressive behavior and favorable prognosis in NPC patients. FOXA1 could contribute in the EMT process through key factors as E-cadherin, Twist1, and LMP1.

microRNA-146b promotes neuroblastoma cell growth through targeting NUMB

Accumulating evidence has demonstrated that the abnormal expression of microRNA (miRNA/miR) serves a crucial role in the development of numerous types of human cancer, including neuroblastoma (NB). The present study aimed to investigate the expression levels and biological roles of miR-146b in NB. miR-146b expression levels in NB cell lines and human umbilical vein endothelial cells (HUVECs) were analyzed using reverse transcription-quantitative PCR, and the regulatory effects of miR-146b on NB cell proliferation, invasion and apoptosis in vitro were investigated using CCK-8 assay, transwell invasion assay and flow cytometry. In addition, bioinformatics analysis, western blotting and dual-luciferase reporter assays were used to determine whether NUMB was a target gene of miR-146b. miR-146b expression levels were increased in NB cell lines compared with HUVECs. The knockdown of miR-146b using a miR-146b inhibitor significantly inhibited NB cell proliferation and invasion, but promoted cell apoptosis in vitro. Furthermore, it was revealed that miR-146b promoted NB cell proliferation through targeting NUMB. In conclusion, miR-146b was suggested to serve as an oncogene, at least in part, through directly targeting NUMB, which indicated that miR-146b may be a potential therapeutic target for NB treatment.