HIF-1α, NOTCH1, ADAM12, and HB-EGF are overexpressed in mucoepidermoid carcinoma

Hypoxia-Induced Biosynthesis of the Extracellular Matrix Molecules, Perlecan and Fibronectin, Promotes the Growth of Pleomorphic Adenoma Cells In Vitro Models

Salivary pleomorphic adenoma is histopathologically characterized by its colorful stroma with myxoid, chondroid, and hyaline appearances, due to enhanced biosynthesis of extracellular matrix (ECM) molecules and poor vascularity. Thus, pleomorphic adenoma cells embedded in the stroma typically survive under hypoxic conditions. We determined the expression kinetics of ECM molecules, such as perlecan and fibronectin (FN), under hypoxia in SM-AP1 cells which are duct epithelial differentiated cells, and in SM-AP4 cells, which are myoepithelial differentiated cells, cloned from pleomorphic adenoma of the parotid gland. We investigated hypoxia-inducible factor-1α (HIF-1α)-inducing pathways through a variety of ECM molecules in association with their cellular proliferation and migration. We observed that hypoxic conditions with elevated HIF-1α protein levels induced increased expression of perlecan and FN in SM-AP cells than in controls. Moreover, perlecan and FN knockdown reduced the proliferation of SM-AP1 and SM-AP4 cells under hypoxia. Further, SM-AP1 cell migration was enhanced by both perlecan and FN knockdown, whereas SM-AP4 cell migration was increased by perlecan knockdown and inhibited by fibronectin knockdown. The results indicated that pleomorphic adenoma cells can survive under hypoxic conditions by promoting cell proliferation via enhanced synthesis of ECM molecules. Overall, ECM molecules may be a new anti-tumor target under hypoxic conditions.

ADAM12 promotes the resistance of lung adenocarcinoma cells to EGFR-TKI and regulates the immune microenvironment by activating PI3K/Akt/mTOR and RAS signaling pathways

Lung adenocarcinoma (LUAD) is a malignant respiratory disease, resulting in a heavy social burden. Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) resistance and tumor immune microenvironment are important directions in the treatment of LUAD. In this study, we confirmed the role of ADAM metallopeptidase domain 12 (ADAM12) in LUAD development and progression. Our bioinformatic analysis was conducted to screen ADAM12 was correlated with EGFR-TKI and immune infiltration in LUAD patients. Our results showed that the transcription and post-transcription level of ADAM12 is significantly increased in tumor samples compared to normal samples, and ADAM12 correlated with poor prognosis in LUAD patients. High level of ADAM12 accelerated the LUAD progression via promoting proliferation, cell cycle, apoptosis escaping, immune escaping, EGFR-TKI resistance, angiogenesis, invasion and migration based on experiment validation in vitro and in vivo, which could be attenuated by ADAM12 knockdown. Further mechanistic studies suggested that the PI3K/Akt/mTOR and RAS signaling pathways were activated after ADAM12 knockdown. Therefore, ADAM12 might be validated as a possible molecular therapy target and prognostic marker for patients with LUAD.

Particulate matter promotes cancer metastasis through increased HBEGF expression in macrophages

Although many cohort studies have reported that long-term exposure to particulate matter (PM) can cause lung cancer, the molecular mechanisms underlying the PM-induced increase in cancer metastasis remain unclear. To determine whether PM contributes to cancer metastasis, cancer cells were cultured with conditioned medium from PM-treated THP1 cells, and the migration ability of the treated cancer cells was assessed. The key molecules involved were identified using RNA-seq analysis. In addition, metastatic ability was analyzed in vivo by injection of cancer cells into the tail vein and intratracheal injection of PM into the lungs of C57BL/6 mice. We found that PM enhances the expression of heparin-binding EGF-like growth factor (HBEGF) in macrophages, which induces epithelial-to-mesenchymal transition (EMT) in cancer cells, thereby increasing metastasis. Macrophage stimulation by PM results in activation and subsequent nuclear translocation of the aryl hydrocarbon receptor and upregulation of HBEGF. Secreted HBEGF activates EGFR on the cancer cell surface to induce EMT, resulting in increased migration and invasion in vitro and increased metastasis in vivo. Therefore, our study reveals a critical PM-macrophage-cancer cell signaling axis mediating EMT and metastasis and provides an effective therapeutic approach for PM-induced malignancy.

Vitamin D ameliorates asthma‐induced lung injury by regulating HIF‐1α/Notch1 signaling during autophagy

Herein, we aimed to determine the effect of vitamin D (Vit D) and underlying mechanisms on asthma‐induced lung injury via regulation of HIF‐1α/Notch1 (hypoxia‐inducible factor 1 alpha/neurogenic locus notch homolog protein 1) signaling during autophagy. We established an asthma mouse model using respiratory syncytial virus (RSV) nasal drop combined with ovalbumin (OVA) atomization. Mice were treated with different Vit D concentrations. Pathological changes and cell apoptosis were examined using hematoxylin–eosin (HE) staining and TUNEL (terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate (dUTP) nick end‐labeling) assay, respectively. Additionally, periodic acid–Schiff (PAS) and Masson's trichrome staining solutions were used to examine changes in lung tissue. Immunofluorescence determined LC 3B (microtubule‐associated protein 1 light chain 3B) expression in lung tissues, whereas western blotting and immunohistochemistry were used to evaluate other proteins, including HIF‐1α and Notch1. Compared with the normal group, the asthma model group exhibited pathological lung tissue deterioration, elevated fibrosis, increased apoptosis cell numbers, and upregulated autophagy. Vitamin D supplementation ameliorated pathological changes and fibrosis in the lung tissue. Furthermore, Vit D treatment significantly suppressed apoptotic cell numbers and autophagy while enhancing the HIF‐1α/Notch1 pathway. Given the HIF‐1α/Notch1 agonistic activity, Vit D treatment inhibited apoptosis cell numbers, which were increased following asthma‐induced upregulation of autophagy. Vitamin D improved asthma‐induced lung tissue injury by suppressing autophagy via regulation of HIF‐1α/Notch1 signaling in vivo.

Identification of Potential Chemical Substrates as Fuel for Hypoxic Tumors That May Be Linked to Invadopodium Formation in Hypoxia-Induced MDA-MB-231 Breast-Cancer Cell Line

Hypoxia plays a significant role in solid tumors by the increased expression of hypoxia-inducible factor-1α (HIF-1α), which is known to promote cancer invasion and metastasis. Cancer-cell invasion dynamically begins with the degradation of the extracellular matrix (ECM) via invadopodia formation. The chemical substrates that are utilized by hypoxic cells as fuel to drive invadopodia formation are still not fully understood. Therefore, the aim of the study was to maintain MDA-MB-231 cells under hypoxia conditions to allow cells to form a large number of invadopodia as a model, followed by identifying their nutrient utilization. The results of the study revealed an increase in the number of cells forming invadopodia under hypoxia conditions. Moreover, Western blot analysis confirmed that essential proteins for hypoxia and invadopodia, including HIF-1α, vascular endothelial growth factor (VEGF), metallopeptidase-2 (MMP-2), and Rho guanine nucleotide exchange factor 7 (β-PIX), significantly increased under hypoxia. Interestingly, phenotype microarray showed that only 11 chemical substrates from 367 types of substrates were significantly metabolized in hypoxia compared to in normoxia. This is thought to be fuel for hypoxia to drive the invasion process. In conclusion, we found 11 chemical substrates that could have potential energy sources for hypoxia-induced invadopodia formation of these cells. This may in part be a target in the hypoxic tumor and invadopodia formation. Additionally, these findings can be used as potential carrier targets in cancer-drug discovery, such as the usage of dextrin.

Novel Approaches and Challenges of Discovery of Exosite Modulators of a Disintegrin and Metalloprotease 10

A disintegrin and metaproteinase 10 is an important target for multiple therapeutic areas, however, despite drug discovery efforts by both industry and academia no compounds have reached the clinic so far. The lack of enzyme and substrate selectivity of developmental drugs is believed to be a main obstacle to the success. In this review, we will focus on novel approaches and associated challenges in discovery of ADAM10 selective modulators that can overcome shortcomings of previous generations of compounds and be translated into the clinic.

Role of hypoxia-related proteins in adenoid cystic carcinoma invasion

BACKGROUND

Among cancers affecting the oral cavity, adenoid cystic carcinoma (ACC) is a relatively common malignant neoplasm. It has high rates of metastasis and recurrence and is associated with significant morbidity. During the progression of ACC, the oxygen concentration is reduced in specific areas of the tumour microenvironment, leading to intratumoural hypoxia. The expression of NOTCH1, a disintegrin and metalloproteinase 12 (ADAM-12), hypoxia-inducible factor 1 alpha (HIF-1α), and heparin-binding epidermal growth factor (HB-EGF) under hypoxic conditions has been implicated in invadopodia formation, tumour invasiveness, and metastasis. The aim of this study was to analyse the expression of these proteins to elucidate the mechanisms underlying ACC invasiveness.

METHODS

Fifteen ACC samples and 10 normal-looking salivary gland (SG) samples were used to investigate the expression of these proteins by immunohistochemistry. Primary antibodies against NOTCH1, ADAM-12, HIF-1α, and HB-EGF were used.

RESULTS

The immunoexpression of all proteins was higher in ACC samples than in SG samples (p < 0.05).

CONCLUSIONS

There was increased expression of proteins associated with hypoxia and tumour invasiveness in ACC samples, which indicates a possible role of these proteins in the biological behaviour of this tumour.