Tumor necrosis factor α accelerates Hep-2 cells proliferation by suppressing TRPP2 expression

Metabolic heterogeneity in tumor microenvironment - A novel landmark for immunotherapy

The surrounding non-cancer cells and tumor cells that make up the tumor microenvironment (TME) have various metabolic rhythms. TME metabolic heterogeneity is influenced by the intricate network of metabolic control within and between cells. DNA, protein, transport, and microbial levels are important regulators of TME metabolic homeostasis. The effectiveness of immunotherapy is also closely correlated with alterations in TME metabolism. The response of a tumor patient to immunotherapy is influenced by a variety of variables, including intracellular metabolic reprogramming, metabolic interaction between cells, ecological changes within and between tumors, and general dietary preferences. Although immunotherapy and targeted therapy have made great strides, their use in the accurate identification and treatment of tumors still has several limitations. The function of TME metabolic heterogeneity in tumor immunotherapy is summarized in this article. It focuses on how metabolic heterogeneity develops and is regulated as a tumor progresses, the precise molecular mechanisms and potential clinical significance of imbalances in intracellular metabolic homeostasis and intercellular metabolic coupling and interaction, as well as the benefits and drawbacks of targeted metabolism used in conjunction with immunotherapy. This offers insightful knowledge and important implications for individualized tumor patient diagnosis and treatment plans in the future.

USP39 Promotes the Viability and Migration of Head and Neck Squamous Cell Carcinoma Cell by Regulating STAT1

Objective: Ubiquitin-specific peptidase 39 (USP39) plays a carcinogenic role in many cancers, but little research has been conducted examining whether it is involved in head and neck squamous cell carcinoma (HNSCC). Therefore, this study explored the functional role of USP39 in HNSCC. Method: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify differentially expressed proteins (DEPs) between the HNSCC tumor and adjacent healthy tissues. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to assess the functional enrichment of DEPs. Immunohistochemistry was used to detect protein expression. The viability and migration of two HNSCC cell lines, namely CAL27 and SCC25, were detected using the cell counting kit-8 assay and a wound healing assay, respectively. Quantitative real-time PCR was used to detect the expression level of signal transducer and activator of transcription 1 (STAT1) mRNA. Results: LC-MS/MS results identified 590 DEPs between HNSCC and adjacent tissues collected from 4 patients. Through GO and KEGG pathway analyses, 34 different proteins were found to be enriched in the spliceosome pathway. The expression levels of USP39 and STAT1 were significantly higher in HNSCC tumor tissue than in adjacent healthy tissue as assessed by LC-MS/MS analysis, and the increased expression of USP39 and STAT1 protein was confirmed by immunohistochemistry in clinical samples collected from 7 additional patients with HNSCC. Knockdown of USP39 or STAT1 inhibited the viability and migration of CAL27 and SCC25 cells. In addition, USP39 knockdown inhibited the expression of STAT1 mRNA in these cells. Conclusion: Our findings indicated that USP39 knockdown may inhibit HNSCC viability and migration by suppressing STAT1 expression. The results of this study suggest that USP39 may be a potential new target for HNSCC clinical therapy or a new biomarker for HNSCC.

TRPP2 ion channels: The roles in various subcellular locations

TRPP2 (PC2, PKD2 or Polycytin-2), encoded by PKD2 gene, belongs to the nonselective cation channel TRP family. Recently, the three-dimensional structure of TRPP2 was constructed. TRPP2 mainly functions in three subcellular compartments: endoplasmic reticulum, plasma membrane and primary cilia. TRPP2 can act as a calcium-activated intracellular calcium release channel on the endoplasmic reticulum. TRPP2 also interacts with other Ca²⁺ release channels to regulate calcium release, like IP3R and RyR2. TRPP2 acts as an ion channel regulated by epidermal growth factor through activation of downstream factors in the plasma membrane. TRPP2 binding to TRPC1 in the plasma membrane or endoplasmic reticulum is associated with mechanosensitivity. In cilium, TRPP2 was found to combine with PKD1 and TRPV4 to form a complex related to mechanosensitivity. Because TRPP2 is involved in regulating intracellular ion concentration, TRPP2 mutations often lead to autosomal dominant polycystic kidney disease, which may also be associated with cardiovascular disease. In this paper, we review the molecular structure of TRPP2, the subcellular localization of TRPP2, the related functions and mechanisms of TRPP2 at different sites, and the diseases related to TRPP2.

Role of the AMPK/ACC Signaling Pathway in TRPP2-Mediated Head and Neck Cancer Cell Proliferation

Transient receptor potential polycystic 2 (TRPP2) exerts vital roles in various types of cancer; however, its underlying mechanisms remain largely unknown. This study is aimed at investigating whether knockdown of TRPP2 affected the AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling pathway and the proliferation of HN-4, cell line originating from human oral and hypopharyngeal squamous cell carcinoma. In addition, the interactions among AMPK/ACC, AMPK/protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2α (eIF2α) and TRPP2/PERK/eIF2α signaling pathways, and their association with cell proliferation were also explored. The results showed that the relative expression levels of phosphorylated (p)-ACC, p-PERK, and p-eIF2α in HN-4 cells were significantly increased following treatment with 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) and significantly decreased in cells treated with compound C. Therefore, consistent with previous studies, the AMPK/ACC and AMPK/PERK/eIF2α signaling pathways were upregulated and downregulated following treatment with an AMPK agonist and inhibitor, respectively. Furthermore, TRPP2 knockdown decreased p-PERK and p-eIF2α expression levels and increased those of p-AMPK and p-ACC. Additionally, knockdown of TRPP2 increased HN-4 cell proliferation, while treatment with an AMPK inhibitor or agonist increased or inhibited TRPP2-specific siRNA-mediated cell proliferation, respectively. In conclusion, silencing of TRPP2 expression increased HN-4 cell proliferation via inhibiting the PERK/eIF2α signaling pathway, while the AMPK/ACC signaling pathway was possibly activated by a feedback mechanism to reduce enhanced cell proliferation.

TNF-α suppresses sweat gland differentiation of MSCs by reducing FTO-mediated m6A-demethylation of Nanog mRNA

An effect of inhibition of tumor necrosis factor-α (TNF-α) on differentiation of mesenchymal stromal cells (MSCs) has been demonstrated, but the exact mechanisms that govern MSCs differentiation remain to be further elucidated. Here, we show that TNF-α inhibits the differentiation of MSCs to sweat glands in a specific sweat gland-inducing environment, accompanied with reduced expression of Nanog, a core pluripotency factor. We elucidated that fat mass and obesity-associated protein (FTO)-mediated m⁶A demethylation is involved in the regulation of MSCs differentiation potential. Exposure of MSCs to TNF-α reduced expression of FTO, which demethylated Nanog mRNA. Reduced expression of FTO increased Nanog mRNA methylation, decreased Nanog mRNA and protein expression, and significantly inhibited MSCs capacity for differentiation to sweat gland cells. Our finding is the first to elucidate the functional importance of m⁶A modification in MSCs, providing new insights that the microenvironment can regulate the multipotency of MSCs at the post-transcriptional level. Moreover, to maintain differentiation capacity of MSCs by regulating m⁶A modification suggested a novel potential therapeutic target for stem cell-mediated regenerative medicine.

Ion Channel Dysregulation in Head and Neck Cancers: Perspectives for Clinical Application

Head and neck cancers are a highly complex and heterogeneous group of malignancies that involve very diverse anatomical structures and distinct aetiological factors, treatments and clinical outcomes. Among them, head and neck squamous cell carcinomas (HNSCC) are predominant and the sixth most common cancer worldwide with still low survival rates. Omic technologies have unravelled the intricacies of tumour biology, harbouring a large diversity of genetic and molecular changes to drive the carcinogenesis process. Nonetheless, this remarkable heterogeneity of molecular alterations opens up an immense opportunity to discover novel biomarkers and develop molecular-targeted therapies. Increasing evidence demonstrates that dysregulation of ion channel expression and/or function is frequently and commonly observed in a variety of cancers from different origin. As a consequence, the concept of ion channels as potential membrane therapeutic targets and/or biomarkers for cancer diagnosis and prognosis has attracted growing attention. This chapter intends to comprehensively and critically review the current state-of-art ion channel dysregulation specifically focusing on head and neck cancers and to formulate the major challenges and research needs to translate this knowledge into clinical application. Based on current reported data, various voltage-gated potassium (K_v) channels (i.e. K_v3.4, K_v10.1 and K_v11.1) have been found frequently aberrantly expressed in HNSCC as well as precancerous lesions and are highlighted as clinically and biologically relevant features in both early stages of tumourigenesis and late stages of disease progression. More importantly, they also emerge as promising candidates as cancer risk markers, tumour markers and potential anti-proliferative and anti-metastatic targets for therapeutic interventions; however, the oncogenic properties seem to be independent of their ion-conducting function.

Shenfu Injection Attenuates Bile Duct Injury in Rats with Acute Obstructive Cholangitis

Background: We investigated the effect of Shenfu injection (SFI) in Wistar rats with acute obstructive cholangitis (AOC) and considered the possible molecular mechanisms of the effects. Methods: The 96 rats were divided randomly into three groups. In one group, the common bile duct was subjected to ligation (BDL), and 0.2 mL of saline was injected into the proximal bile ducts. To create AOC, again, the common bile duct was ligated, and 0.2 mL of lipopolysaccharide (LPS)) (2 mg/mL) was injected into the proximal ducts. In the Shenfu injection (SFI) group, the material (10 mg/kg) was injected into the tail vein 2 hours before induction of AOC. The hepatic histopathologic changes were observed under a light microscope. The endotoxin, tumor necrosis factor-α (TNF-α), alanine transaminase (ALT), and total bilirubin (TB) concentrations in the serum were measured at different time points (0, 4, 8, and 16 hours) after ligation. The expression of nuclear transcription factor-κB (NF-κB) and CD14 in Kupffer cells also was analyzed at different times by Western blotting. Results: The TNF-α, ALT, and TB concentrations in the serum and the expression of CD14 and NF-κB in Kupffer cells were significantly higher in the SFI group than in the BDL group, but all were significantly lower than in the AOC group. Compared with the AOC group, the edema of cholangiocytes was alleviated in the SFI group, and the infiltration of inflammatory cells around cholangiocytes was reduced. Conclusion: Shenfu injection significantly alleviated bile duct injury. The potential mechanism may be associated with inhibition of CD14 expression and prevention of NF-κB activation in Kupffer cells.

Exosome-delivered TRPP2 siRNA inhibits the epithelial-mesenchymal transition of FaDu cells

The prognosis for patients with head and neck cancer (HNC) remains poor, owing to uncontrolled tumor invasion and metastasis. Epithelial-mesenchymal transition (EMT) serves an important role in this invasion and metastasis, and transient receptor potential polycystic 2 (TRPP2) enhances metastasis and invasion by regulating EMT in human laryngeal squamous cell carcinoma. The present study examined whether exosomes/TRPP2 small interfering RNA (siRNA) complexes were able to reduce EMT by suppressing TRPP2 expression in FaDu cells, a cell line of human pharyngeal squamous cell carcinoma. Using agarose gel electrophoresis, it was determined that exosome/TRPP2 siRNA complexes were stable in the presence of nucleases and serum. A fluorescence assay and western blotting analysis was performed, and it was reported that the FaDu cells took up exosomes, the exosomes effectively delivered TRPP2 siRNA into FaDu cells and that exosome/TRPP2 siRNA complexes significantly suppressed TRPP2 protein expression levels in FaDu cells. Furthermore, expression levels of E-cadherin were significantly increased, whereas expression levels of N-cadherin and vimentin were significantly decreased in FaDu cells transfected with TRPP2 siRNA. Thus, exosome/TRPP2 siRNA complexes markedly suppressed TRPP2 expression and EMT in FaDu cells. These results suggested that further development of exosome/TRPP2 siRNA complexes for use as an RNA-based gene therapy in the treatment of HNC is warranted.

Inflammatory cytokines tumour necrosis factor-α and interleukin-8 enhance airway smooth muscle contraction by increasing L-type Ca2+ channel expression

Inflammation elevates intracellular calcium concentrations ([Ca²⁺ ]_i ) in airway smooth muscle (ASM). The L-type Ca²⁺ channel (L-VDCC) plays an important role in regulating Ca²⁺ influx in ASM. However, the role of L-VDCC in the inflammatory cytokine-induced pathology of ASM remains unclear. In the present study, we used calcium imaging and isometric tension measurements to assess the role of L-VDCC in agonist-induced [Ca²⁺ ]_i rise and the associated contractions in mouse ASM, and we used immunoblotting to identify L-VDCC protein expression levels in mouse ASM after exposure to tumour necrosis factor alpha (TNF-α) or interleukin-8 (IL-8). Our results showed that high-K⁺ - or carbachol-induced contractions of mouse ASM were significantly greater after pretreatment with TNF-α or IL-8 for 24 hours. Both verapamil and nifedipine, L-VDCC inhibitors, abolished this increased contraction induced by TNF-α or IL-8 pretreatment. Moreover, TNF-α treatment enhanced carbachol-induced Ca²⁺ influx in ASM cells, and this effect was abrogated by verapamil. Additionally, immunoblotting results showed that preincubation of mouse ASM with TNF-α or IL-8 also enhanced L-VDCC protein expression. On the basis of these findings, we concluded that proinflammatory cytokines, such as TNF-α and IL-8, increase the expression level of L-VDCC, which in turn contributes to augmented agonist-induced ASM contractions. This effect of inflammation on L-VDCC expression in ASM may be associated with airway hyper-responsiveness and involved in the development of asthma.