PTEN activation sensitizes breast cancer to PI3-kinase inhibitor through the β-catenin signaling pathway

Concurrent PTEN and PDGFRB Alterations Characterize Storiform Collagenoma

Storiform collagenoma is a rare mesenchymal skin tumor that is composed of thickened collagen bundles arranged in a characteristic storiform pattern with a relatively hypocellular CD34-positive spindle cell component. Storiform collagenoma is most often sporadic, but multiple lesions can occur in Cowden syndrome, which is characterized by germline alterations in PTEN (phosphatase and tensin homolog) on chromosome 10. Here, we investigated the molecular pathogenesis of storiform collagenoma using a targeted next-generation DNA sequencing platform, including 5 sporadic cases and one case associated with Cowden syndrome. Recurrent PTEN alterations were identified in all cases, with biallelic PTEN inactivation observed in the case associated with Cowden syndrome and one sporadic case. Unexpectedly, we also identified recurrent activating mutations in the platelet-derived growth factor receptor beta ( PDGFRB ) gene. This included a missense substitution in the D5 Ig-like domain of PDGFRB in the Cowden syndrome-associated case. In addition, we report missense alterations in the juxtamembrane domain of PDGFRB in 4 of 5 (80%) sporadic cases, including mutations that have been previously described in sporadic myofibroma and myopericytoma. Therefore, we confirm the neoplastic nature of storiform collagenoma, we expand the spectrum of reported PDGFRB alterations in mesenchymal tumors and we suggest a possible collaborative role for PTEN and PDGFRB in the pathogenesis of storiform collagenoma.

The use of adenoviral vectors in gene therapy and vaccine approaches

Adenovirus was first identified in the 1950s and since then this pathogenic group of viruses has been explored and transformed into a genetic transfer vehicle. Modification or deletion of few genes are necessary to transform it into a conditionally or non-replicative vector, creating a versatile tool capable of transducing different tissues and inducing high levels of transgene expression. In the early years of vector development, the application in monogenic diseases faced several hurdles, including short-term gene expression and even a fatality. On the other hand, an adenoviral delivery strategy for treatment of cancer was the first approved gene therapy product. There is an increasing interest in expressing transgenes with therapeutic potential targeting the cancer hallmarks, inhibiting metastasis, inducing cancer cell death or modulating the immune system to attack the tumor cells. Replicative adenovirus as vaccines may be even older and date to a few years of its discovery, application of non-replicative adenovirus for vaccination against different microorganisms has been investigated, but only recently, it demonstrated its full potential being one of the leading vaccination tools for COVID-19. This is not a new vector nor a new technology, but the result of decades of careful and intense work in this field.

LPS/TLR4 pathways in breast cancer: insights into cell signalling

BACKGROUND

Cancer cells are usually recognized as foreign particles by the immune cells. Mounting evidences suggest important link between toll like receptors (TLRs) and carcinogenesis. This review article focused on the role of TLRs, especially TLR4 in breast cancer. <p> Methods: Research data on TLRs and cancer was explored in PubMed, Scopus, Google Scholar, and reviewed. Although some pioneer works are referenced, papers published in last ten years were mostly cited. <p> Results: TLRs are widely investigated pattern recognition receptors (PRR), and TLR4 is the most studied TLRs, implicated with occurrence of several types of cancers including breast cancer. TLR4 activation occurs via the binding of its ligand lipopolysaccharide (LPS), a component of the outer membrane of gram negative bacteria. Upon LPS binding, TLR4 dimerizes and recruits downstream signalling and/or adapter molecules leading to gene expression related to cancer cell proliferation, survival, invasion, and metastasis. Although LPS/TLR4 signalling seems a single signal transduction pathway, the TLR4 activation results in the activation of multiple diverse intracellular networks with huge cellular responses in both immune and cancer cells. The role of TLR4 in growth, invasion and metastasis of breast cancer is attracting huge attention in oncology research. Several clinical and preclinical studies utilize both TLR4 agonists and antagonists as treatment option for cancer therapy either as monotherapy or adjuvants for vaccine development. <p> Conclusion: This review narrates the role of LPS/TLR4 signalling in breast cancer development and future prospective for targeting LPS/TLR4 axis in the treatment of breast cancer.

Polyphenol-Enriched Blueberry Preparation Controls Breast Cancer Stem Cells by Targeting FOXO1 and miR-145

Scientific evidence supports the early deregulation of epigenetic profiles during breast carcinogenesis. Research shows that cellular transformation, carcinogenesis, and stemness maintenance are regulated by epigenetic-specific changes that involve microRNAs (miRNAs). Dietary bioactive compounds such as blueberry polyphenols may modulate susceptibility to breast cancer by the modulation of CSC survival and self-renewal pathways through the epigenetic mechanism, including the regulation of miRNA expression. Therefore, the current study aimed to assay the effect of polyphenol enriched blueberry preparation (PEBP) or non-fermented blueberry juice (NBJ) on the modulation of miRNA signature and the target proteins associated with different clinical-pathological characteristics of breast cancer such as stemness, invasion, and chemoresistance using breast cancer cell lines. To this end, 4T1 and MB-MDM-231 cell lines were exposed to NBJ or PEBP for 24 h. miRNA profiling was performed in breast cancer cell cultures, and RT-qPCR was undertaken to assay the expression of target miRNA. The expression of target proteins was examined by Western blotting. Profiling of miRNA revealed that several miRNAs associated with different clinical-pathological characteristics were differentially expressed in cells treated with PEBP. The validation study showed significant downregulation of oncogenic miR-210 expression in both 4T1 and MDA-MB-231 cells exposed to PEBP. In addition, expression of tumor suppressor miR-145 was significantly increased in both cell lines treated with PEBP. Western blot analysis showed a significant increase in the relative expression of FOXO1 in 4T1 and MDA-MB-231 cells exposed to PEBP and in MDA-MB-231 cells exposed to NBJ. Furthermore, a significant decrease was observed in the relative expression of N-RAS in 4T1 and MDA-MB-231 cells exposed to PEBP and in MDA-MB-231 cells exposed to NBJ. Our data indicate a potential chemoprevention role of PEBP through the modulation of miRNA expression, particularly miR-210 and miR-145, and protection against breast cancer development and progression. Thus, PEBP may represent a source for novel chemopreventative agents against breast cancer.

Physical defects in basement membrane-mimicking collagen-IV matrices trigger cellular EMT and invasion

In fibrosis and cancer, degradation of basement membrane (BM) and cell invasion are considered as key outcomes of a cellular transformation called epithelial-mesenchymal transition (EMT). Here, we pose a converse question - can preexisting physical defects in the BM matrix cause EMT in normal epithelial cells? On a BM-mimicking matrix of collagen-IV-coated polyacrylamide (PA) gel, we have discovered a reverse phenomenon in which preexisting defects trigger EMT in normal epithelial cells. Through spatiotemporal measurements and simulations in silico, we demonstrate that the EMT precedes cellular mechanoactivation on defective matrices, but they occur concurrently on stiff matrices. The defect-dependent EMT caused cell invasion though a stroma-mimicking collagen-I layer, which could be disabled through MMP9 inhibition. Our findings reveal that the known BM degradation caused by cellular EMT and invasion is not a one-way process. Instead, normal epithelial cells can exploit physical defects in the BM matrix to undergo disease-like cellular transformations.

IL-17A promotes cell migration and invasion of glioblastoma cells via activation of PI3K/AKT signalling pathway

Glioblastomas (GBMs) are the most common of both benign and malignant primary brain tumours, in which the inflammatory and immunologic abnormalities are involved. Interleukin-17A (IL-17A) plays an important role in various inflammatory diseases and cancers. Several recent studies revealed that the expression of IL-17A was overexpressed in human GBMs tissue. However, the accurate role of IL-17A in GBMs remains unclear. In this study, we aimed to explore the effect of IL-17A on cell migration and invasion of GBMs and the mechanism by which the effects occurred. We found that exogenous IL-17A promoted significantly cell migration and invasion abilities in two GBMs cell lines (U87MG and U251) in a time-dependent manner. In addition, the protein expressions of PI3K, Akt and MMP-2/9 were increased in the GBMs cells challenged by IL-17A. Furthermore, a tight junction protein ZO-1 was down-regulated but Twist and Bmi1 were up-regulated. Treatment with a PI3K inhibitor (LY294002) significantly reduced the abilities of both migration and invasion in U87MG and U251 cells. LY294002 treatment also attenuated the IL-17A causing increases of protein levels of PI3K, AKT, MMP-2/9, Twist and the decreases of protein level of ZO-1 in the U87MG and U251 cells. Taken together, we concluded that IL-17A promotes the GBM cells migration and invasion via PI3K/AKT signalling pathway. IL-17A and its related signalling pathways may be potential therapeutic targets for GBM.

Protein Kinase Targets in Breast Cancer

With 1.67 million new cases and 522,000 deaths in the year 2012, breast cancer is the most common type of diagnosed malignancy and the second leading cause of cancer death in women around the world. Despite the success of screening programs and the development of adjuvant therapies, a significant percentage of breast cancer patients will suffer a metastatic disease that, to this day, remains incurable and justifies the research of new therapies to improve their life expectancy. Among the new therapies that have been developed in recent years, the emergence of targeted therapies has been a milestone in the fight against cancer. Over the past decade, many studies have shown a causal role of protein kinase dysregulations or mutations in different human diseases, including cancer. Along these lines, cancer research has demonstrated a key role of many protein kinases during human tumorigenesis and cancer progression, turning these molecules into valid candidates for new targeted therapies. The subsequent discovery and introduction in 2001 of the kinase inhibitor imatinib, as a targeted treatment for chronic myelogenous leukemia, revolutionized cancer genetic pathways research, and lead to the development of multiple small-molecule kinase inhibitors against various malignancies, including breast cancer. In this review, we analyze studies published to date about novel small-molecule kinase inhibitors and evaluate if they would be useful to develop new treatment strategies for breast cancer patients.

Multi-focal sequencing of a diffuse intrinsic pontine glioma establishes PTEN loss as an early event

Improved molecular understanding is needed for rational treatment of diffuse intrinsic pontine gliomas (DIPG). Here, using multi-focal paired tumor and germline exome DNA and RNA sequencing, we uncovered phosphatase and tensin homolog (PTEN) loss as a clonal mutation in the case of a 6-year-old boy with a diffuse intrinsic pontine glioma, and incorporated copy number alteration analyses to provide a more detailed understanding of clonal evolution in diffuse intrinsic pontine gliomas. As well, using the PedcBioPortal, we found alterations in PTEN in 16 of 326 (4.9%) cases of pediatric high-grade glioma (3 of 154 (1.9%) brainstem) for which full sequencing data was available. Our data strengthens the association with PTEN loss in diffuse intrinsic pontine gliomas and provides further argument for the inclusion of PTEN in future targeted sequencing panels for pediatric diffuse intrinsic pontine gliomas and for the development and optimization of mTOR/PI3K inhibitors with optimal central nervous system penetration.

miR-494 promotes cell proliferation, migration and invasion, and increased sorafenib resistance in hepatocellular carcinoma by targeting PTEN

MicroRNA-494 (miR-494) acts as an oncomiR and is involved in tumor development, progression and metastasis, and confers resistance to chemotherapeutic drugs by targeting a number of molecules in several human cancers. However, the function and underlying molecular mechanism of miR-494 in hepatocellular carcinoma (HCC) has not been totally elucidated. In the present study, we determined the role played by miR-494 in HCC tissues and HCC cell lines using quantitative RT-PCR (RT-qPCR). The results showed that, miR-494 was significantly upregulated in HCC tissues and HCC cell lines. Additionally, a high miR-494 expression positively correlated with tumor differentiation (P<0.01), TNM stage (P<0.01) and lymph node metastasis (P<0.01). Luciferase reporter assays confirmed that miR-494 binds to the 3'-untranslated region (3'-UTR) of the phosphatase and tensin homolog (PTEN) mRNA and represses its translation. Functional analyses indicated that the upregulation of miR-494 promoted cell viability, migration and invasion, decreased cell apoptosis and cell cycle arrest at G1 stage, and conferred sorafenib resistance to HCC cell lines. Underexpression of PTEN by siRNA significantly attenuated the inhibitory effects of anti-miR-494 on the proliferation, migration and invasion of liver cancer cells. Mechanistic investigations revealed that miR-494 suppressed the expression of PTEN but increased the expression of PI3K and p-Akt, which contribute to the promotion of proliferation, migration and invasion, and increased sorafenib resistance to HCC cell lines. These findings suggested that miR-494 is a potential candidate for HCC therapeutics.

Role of runt-related transcription factor 2 in signal network of tumors as an inter-mediator

Runt-related transcription factor 2 (RUNX2) is a member of the polyomavirus enhancer-binding protein 2/core-binding factor superfamily. RUNX2 is known for its contribution to osteoblast phenotype and bone formation. In recent years, increasing attention has been focused on the relationship of Runx2 with tumorigenesis. In different types of tumor cells, RUNX2 cooperates with its co-activators or co-inhibitors, and mediates the responses of cells to various signaling pathways that are hyperactive in tumors. Thus, several downstream target genes of RUNX2 are activated when RUNX2 interacts with its co-factors, leading to a variety of effects on tumor cells (epithelial-mesenchymal transition, metastasis, proliferation, and osteolytic lesion). This review focuses on the involvement of RUNX2 in tumor cells in the crosstalk of diverse signaling pathways and its multiple functions to develop optimal and feasible approaches for clinical treatment based on the functions of RUNX2.