HTRA1 promotes transdifferentiation of normal fibroblasts to cancer-associated fibroblasts through activation of the NF-κB/bFGF signaling pathway in gastric cancer

Progress in the Study of the Role and Mechanism of HTRA1 in Diseases Related to Vascular Abnormalities

High temperature requirement A1 (HTRA1) is a member of the serine protease family, comprising four structural domains: IGFBP domain, Kazal domain, protease domain and PDZ domain. HTRA1 encodes a serine protease, a secreted protein that is widely expressed in the vasculature. HTRA1 regulates a wide range of physiological processes through its proteolytic activity, and is also involved in a variety of vascular abnormalities-related diseases. This article reviews the role of HTRA1 in the development of vascular abnormalities-related hereditary cerebral small vessel disease (CSVD), age-related macular degeneration (AMD), tumors and other diseases. Through relevant research advances to understand the role of HTRA1 in regulating signaling pathways or refolding, translocation, degradation of extracellular matrix (ECM) proteins, thus directly or indirectly regulating angiogenesis, vascular remodeling, and playing an important role in vascular homeostasis, further understanding the mechanism of HTRA1's role in vascular abnormality-related diseases is important for HTRA1 to be used as a therapeutic target in related diseases.

HTRA1 promotes EMT through the HDAC6/Ac-α-tubulin pathway in human GBM cells

BACKGROUND

The infiltrative nature of human gliomas renders complete surgical removal of tumors futile. Thus, illuminating mechanisms of their infiltrative properties may improve therapies and outcomes of glioma patients.

METHODS

Comprehensive bioinformatic analyses of PRSS family were undertaken. Transfection of HTRA1 siRNAs was used to suppress HTRA1 expression. CCK-8, EdU, and colony formation assay were employed to assess cell viability, and cell migration/invasion was detected by transwell, wound healing, and 3D tumor spheroid invasion assays. Immunoprecipitation was applied to study the mechanism that HTRA1 affected cell migration. In addition, in situ xenograft tumor model was employed to explore the role of HTRA1 in glioma growth in vivo.

RESULTS

HTRA1 knockdown could lead to suppression of cell viability, migration and invasion, as well as increased apoptosis. Immunoprecipitation results indicates HTRA1 might facilitate combination between HDAC6 and α-tubulin to enhance cell migration by decreasing α-tubulin acetylation. Besides, HTRA1 knockdown inhibited the growth of xenografts derived from orthotopic implantation of GBM cells and prolonged the survival time of tumor-bearing mice.

CONCLUSION

Our results indicate that HTRA1 promotes the proliferation and migration of GBM cells in vitro and in vivo, and thus may be a potential target for treatment in gliomas.

HtrA3: a promising prognostic biomarker and therapeutic target for head and neck squamous cell carcinoma

Objective

The dysregulation of the human high-temperature requirement A (HtrA) family of serine proteases is associated with many malignancies. However, there are few reports on HtrAs in head and neck squamous cell carcinoma (HNSCC). The aim of this study was to investigate the expression, prognostic value, and biological functions of HtrAs in HNSCC.

Methods

The RNA-sequencing data and clinical data of HNSCC were downloaded from The Cancer Genome Atlas (TCGA) database. The GSE30784 and GSE31056 datasets from the Gene Expression Omnibus (GEO) database were used for further verification. This study explored the differential expression of HtrAs and assessed their potential impact on the prognosis of HNSCC patients using a survival module. Correlations between clinical characteristics and HtrA expression levels were then explored using a Wilcoxon rank sum test. A Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) were performed using "clusterProfile" in the R software. A Pearson/Spearman correlation test was applied to analyze the relationship between HtrAs and immune infiltration level/checkpoint genes. Validation of HtrA expression levels were carried out by RT-PCR and western blot in human squamous carcinoma cell lines (Fadu and Cal-27) and human non-tumorigenic bronchial epithelium cells (BEAS-2B). Finally, through cell transfection, CCK-8, Ki-67 immunofluorescence, and flow cytometry assays, the effect of HtrA3 knockdown on the malignant biological behavior of HNSCC cells was explored.

Results

The gene expression levels of HtrAs were significantly upregulated and associated with patient age, TNM stage, clinical stage, and TP53 mutation status in the TCGA-HNSCC cohort. High expressions of HtrA1/3 were associated with shorter overall survival, shorter progress-free interval, and lower disease-specific survival in HNSCC. A nomogram for HtrAs was constructed and validated. HtrA-related genes were significantly enriched in the immune response and cell apoptosis pathway. In addition, the expression of HtrAs showed significant correlations with B cells, M cells, DC cell infiltration, and immune infiltration checkpoint (CD276, TNFRSF14). Validation of HtrA expression was carried out by RT-PCR and western blot. Results of in vitro experiments indicated that HtrA3 gene knockdown inhibits the proliferation of FaDu and Cal-27 cells while concurrently promoting apoptosis.

Conclusions

HtrA3 shows significant potential as both a prognostic marker and a promising therapeutic target for HNSCC, highlighting its relevance and importance in future research and potential clinical applications.

Fibroblasts as Turned Agents in Cancer Progression

Differentiated epithelial cells reside in the homeostatic microenvironment of the native organ stroma. The stroma supports their normal function, their G0 differentiated state, and their expansion/contraction through the various stages of the life cycle and physiologic functions of the host. When malignant transformation begins, the microenvironment tries to suppress and eliminate the transformed cells, while cancer cells, in turn, try to resist these suppressive efforts. The tumor microenvironment encompasses a large variety of cell types recruited by the tumor to perform different functions, among which fibroblasts are the most abundant. The dynamics of the mutual relationship change as the sides undertake an epic battle for control of the other. In the process, the cancer “wounds” the microenvironment through a variety of mechanisms and attracts distant mesenchymal stem cells to change their function from one attempting to suppress the cancer, to one that supports its growth, survival, and metastasis. Analogous reciprocal interactions occur as well between disseminated cancer cells and the metastatic microenvironment, where the microenvironment attempts to eliminate cancer cells or suppress their proliferation. However, the altered microenvironmental cells acquire novel characteristics that support malignant progression. Investigations have attempted to use these traits as targets of novel therapeutic approaches.

The Novel Protein ADAMTS16 Promotes Gastric Carcinogenesis by Targeting IFI27 through the NF-κb Signaling Pathway

A disintegrin and metalloproteinase with thrombospondin motifs 16 (ADAMTS16) has been reported to be involved in the pathogenesis of solid cancers. However, its role in gastric cancer (GC) is unclear. In this study, the role of ADAMTS16 in gastric cancer was investigated. The effects of ADAMTS16 on cell migration, invasion, and proliferation were investigated by functional experiments in vivo and in vitro. Downstream signal pathways of ADAMTS16 were confirmed by using bioinformatics analysis, co-immunoprecipitation, and immunofluorescence. Meanwhile, bioinformatics analysis, qRT-PCR, western blot, and dual-luciferase reporter gene analysis assays were used to identify ADAMTS16 targets. The expression of ADAMTS16 in GC was analyzed in public datasets. The expression of ADAMTS16 and its correlations with the clinical characteristics of GC were investigated by immunohistochemistry. Ectopic ADAMTS16 expression significantly promoted tumor cell migration, invasion, and growth. Bioinformatics analysis and western blot showed that ADAMTS16 upregulated the IFI27 protein through the NF-κb pathway, which was confirmed by immunofluorescence and western blot. Dual-luciferase reporter gene analysis identified a binding site between P65 and IFI27 that may be directly involved in the transcriptional regulation of IFI27. IFI27 knockdown reversed the promoting effect of ADAMTS16 on cell invasion, migration, and proliferation indicating that ADAMTS16 acts on GC cells by targeting the NF-κb/IFI27 axis. ADAMTS16 was associated with poor prognosis in clinical characteristics. ADAMTS16 promotes cell migration, invasion, and proliferation by targeting IFI27 through the NF-κB pathway and is a potential progressive and survival biomarker of GC.

High temperature requirement A1 in cancer: biomarker and therapeutic target

As the life expectancy of the population increases worldwide, cancer is becoming a substantial public health problem. Considering its recurrence and mortality rates, most cancer cases are difficult to cure. In recent decades, a large number of studies have been carried out on different cancer types; unfortunately, tumor incidence and mortality have not been effectively improved. At present, early diagnostic biomarkers and accurate therapeutic strategies for cancer are lacking. High temperature requirement A1 (HtrA1) is a trypsin-fold serine protease that is also a chymotrypsin-like protease family member originally discovered in bacteria and later discovered in mammalian systems. HtrA1 gene expression is decreased in diverse cancers, and it may play a role as a tumor suppressor for promoting the death of tumor cells. This work aimed to examine the role of HtrA1 as a cell type-specific diagnostic biomarker or as an internal and external regulatory factor of diverse cancers. The findings of this study will facilitate the development of HtrA1 as a therapeutic target.

Tumor-Derived Extracellular Vesicles Promote Activation of Carcinoma-Associated Fibroblasts and Facilitate Invasion and Metastasis of Ovarian Cancer by Carrying miR-630

Ovarian cancer (OC) is a lethal gynecological malignancy. Extracellular vesicles (EVs) are crucial media in cell-to-cell communication by carrying microRNAs (miRs). The current study aims to investigate the underlying mechanism of miR-630 carried by OC cell-derived EVs in regard to invasion and metastasis of OC cells. miRs related to OC metastasis were searched and screened. The expression patterns of screened miRs in human normal fibroblasts (NFs) and carcinoma-associated fibroblasts (CAFs) were detected using RT-qPCR. miR-630 related to OC metastasis and CAFs activation was analyzed further. The levels of FAP and α-SMA were detected using Western blotting and immunofluorescence. The migration of NFs was measured using Transwell assay. OC cell-derived EVs were isolated and identified. Uptake of EVs by NFs was observed using immunofluorescence staining. The culture supernatant of NFs was collected and used to culture the low metastasis cell line OVCAR8. The migration and invasion of OC cells and epithelial mesenchymal transition (EMT) were measured. Moreover, a xenograft model was established by injecting OVCAR8 cells of different groups into nude mice. Lastly, the effect of EV-pretreated NFs on invasion and metastasis of OC cells was observed in vivo. miR-630 was upregulated in OC cells and CAFs, and further associated with CAF activation and OC metastasis. miR-630 overexpression increased the levels of FAP and α-SMA in NFs, resulting in the transformation of NFs into CAFs. EVs carried miR-630 into NFs and EVs promoted CAF activation. miR-630 targeted KLF6. miR-630 inhibition or KLF6 overexpression attenuated EVs-induced CAF activation. EVs activated the NF-κB pathway via the miR-630/KLF6 axis. The conditioned medium of NFs pretreated with EVs promoted the invasion and metastasis of OVCAR8 cells, while downregulating miR-630 in EVs partially inhibited the promotive effect of NFs. EV-pretreated NFs promoted invasion and metastasis of OC in vivo. In conclusion, EVs carried miR-630 into NFs, thereby facilitating CAF activation and promoting invasion and metastasis of OC by inhibiting KLF6 and activating the NF-κB pathway. Our findings might offer a novel mechanism of invasion and metastasis of OC from the perspective of tumor microenvironment.

Signaling pathways in cancer-associated fibroblasts and targeted therapy for cancer

To flourish, cancers greatly depend on their surrounding tumor microenvironment (TME), and cancer-associated fibroblasts (CAFs) in TME are critical for cancer occurrence and progression because of their versatile roles in extracellular matrix remodeling, maintenance of stemness, blood vessel formation, modulation of tumor metabolism, immune response, and promotion of cancer cell proliferation, migration, invasion, and therapeutic resistance. CAFs are highly heterogeneous stromal cells and their crosstalk with cancer cells is mediated by a complex and intricate signaling network consisting of transforming growth factor-beta, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin, mitogen-activated protein kinase, Wnt, Janus kinase/signal transducers and activators of transcription, epidermal growth factor receptor, Hippo, and nuclear factor kappa-light-chain-enhancer of activated B cells, etc., signaling pathways. These signals in CAFs exhibit their own special characteristics during the cancer progression and have the potential to be targeted for anticancer therapy. Therefore, a comprehensive understanding of these signaling cascades in interactions between cancer cells and CAFs is necessary to fully realize the pivotal roles of CAFs in cancers. Herein, in this review, we will summarize the enormous amounts of findings on the signals mediating crosstalk of CAFs with cancer cells and its related targets or trials. Further, we hypothesize three potential targeting strategies, including, namely, epithelial-mesenchymal common targets, sequential target perturbation, and crosstalk-directed signaling targets, paving the way for CAF-directed or host cell-directed antitumor therapy.

HtrA serine proteases in cancers: A target of interest for cancer therapy

The HtrA protein family is composed by evolutionally-conserved serine proteases, which are homologous to the HtrA protein of the model bacterium Escherichia coli. They are widely distributed in organisms including humans, prokaryotes and eukaryotes. Moreover, HtrA family proteins are important regulators of a variety of human physiological processes, which contains the maintenance of mitochondrial homeostasis, cellular signal transduction and apoptosis regulation. The HtrA family has been found to be associated with cancer and could be used as a target for future cancer treatments. The purpose of this article is to review the relationship between these HtrA and cancer and to summarize the latest researches on HtrA and cancer.

Exosomal‑miR‑10a derived from colorectal cancer cells suppresses migration of human lung fibroblasts, and expression of IL‑6, IL‑8 and IL‑1β

MicroRNAs (miRs) carried in exosomes serve an important role in the pre‑metastatic microenvironment and in intercellular interactions. However, the function of exosomal‑miR‑10a derived from primary colorectal cancer (CRC) cells on fibroblasts in the lung metastatic microenvironment of patients with CRC remains unclear. Reverse transcription‑quantitative PCR was performed using samples from patients with CRC, and demonstrated that the expression levels of miR‑10a were significantly lower in serum and cancer tissue samples from patients with CRC compared with in serum from healthy individuals and paired non‑cancerous tissues, respectively. In addition, the expression levels of miR‑10a were inversely associated with the invasion depth of CRC. Exosomal‑miR‑10a derived from CRC cells reduced the proliferative and migratory activities of primary normal human lung fibroblasts (NHLFs), and the expression levels of IL‑6, IL‑8 and IL‑1β in NHLFs. The present study provided insight into the phenotypic alterations of NHLFs induced by exosomal‑miR‑10a derived from CRC cells, which may aid understanding of the mechanism underlying the process of CRC lung metastasis.

Molecular structure and the role of high-temperature requirement protein 1 in skeletal disorders and cancers

Human high‐temperature requirement protein 1 (HTRA1) is a member of serine proteases and consists of four well‐defined domains—an IGFBP domain, a Kazal domain, a protease domain and a PDZ domain. HTRA1 is a secretory protein and also present intracellularly and associated with microtubules. HTRA1 regulates a broad range of physiological processes via its proteolytic activity. This review examines the role of HTRA1 in bone biology, osteoarthritis, intervertebral disc (IVD) degeneration and tumorigenesis. HTRA1 mediates diverse pathological processes via a variety of signalling pathways, such as TGF‐β and NF‐κB. The expression of HTRA1 is increased in arthritis and IVD degeneration, suggesting that HTRA1 protein is attributed to cartilage degeneration and disease progression. Emerging evidence also suggests that HTRA1 has a role in tumorigenesis. Further understanding the mechanisms by which HTRA1 displays as an extrinsic and intrinsic regulator in a cell type–specific manner will be important for the development of HTRA1 as a therapeutic target.

Stromal reprogramming: A target for tumor therapy

Cancer associated fibroblasts (CAFs) as the dominant, long-lived and highly plastic cells within the tumor microenvironment (TME) with multi-faceted roles that are endowed with tumor aggressive features. They can instruct and shape the stroma of tumor into being a highly qualified bed for cellular recruitment, differentiation and plasticity in the host tissue or secondary organ/s. In this Review, we have a discussion over CAF reprogramming as a general concept, inducers and outcomes, pursued by suggesting potential strategies to combat this key promoter of tumor.