Loss of periostin/OSF-2 in ErbB2/Neu-driven tumors results in androgen receptor-positive molecular apocrine-like tumors with reduced Notch1 activity

Periostin promotes extensive neovascularization in placenta accreta spectrum disorders via Notch signaling

OBJECTIVE

Extensive neovascularization, closely linked to massive intraoperative blood loss, is a pathological hallmark of placenta accreta spectrum (PAS) cases. This study aims to explore proteins related to neovascularization and elucidate their regulatory roles in PAS, enhancing our understanding of this condition.

METHODS

The isobaric tags for relative and absolute quantitation technique were used to identify and quantify the differentially expressed proteins in placentas from PAS and healthy pregnant women. Immunofluorescence staining and western blot analysis were conducted to determine the protein expression and localization. Gain-of-function experiments were used to conduct cell proliferation and migration assays. In addition, the tube formation assay was performed to evaluate angiogenesis in vitro. The Notch inhibitor DAPT was used to determine the involvement of Notch signaling in angiogenesis in PAS.

RESULTS

Periostin (POSTN) exhibited higher expression in PAS placentas than in normal placentas. Moreover, the overexpression of POSTN in endothelial cells promoted cell proliferation, mobility, and endothelial angiogenesis via the Notch signaling pathway in vitro.

CONCLUSION

Elevated POSTN expression in PAS is associated with increased angiogenesis, indicating its potential as a molecular marker for significant intraoperative blood loss.

Periostin Is Expressed by Pericytes and Is Crucial for Angiogenesis in Glioma

The expression of the matricellular protein periostin has been associated with glioma progression. In previous work we found an association of periostin with glioma angiogenesis. Here, we screen gliomas for POSTN expression and identify the cells that express periostin in human gliomas. In addition, we study the role of periostin in an in vitro model for angiogenesis. The expression of periostin was investigated by RT-PCR and by immunohistochemistry. In addition, we used double labeling and in situ RNA techniques to identify the expressing cells. To investigate the function of periostin, we silenced POSTN in a 3D in vitro angiogenesis model. Periostin expression was elevated in pilocytic astrocytoma and glioblastoma, but not in grade II/III astrocytomas and oligodendrogliomas. The expression of periostin colocalized with PDGFRβ+ cells, but not with OLIG2+/SOX2+ glioma stem cells. Silencing of periostin in pericytes in coculture experiments resulted in attenuation of the numbers and the length of the vessels formation and in a decrease in endothelial junction formation. We conclude that pericytes are the main source of periostin in human gliomas and that periostin plays an essential role in the growth and branching of blood vessels. Therefore, periostin should be explored as a novel target for developing anti-angiogenic therapy for glioma.

Periostin+ cancer-associated fibroblasts promote lymph node metastasis by impairing the lymphatic endothelial barriers in cervical squamous cell carcinoma

Lymph node metastasis (LNM), a critical prognostic determinant in cancer patients, is critically influenced by the presence of numerous heterogeneous cancer‐associated fibroblasts (CAFs) in the tumor microenvironment. However, the phenotypes and characteristics of the various pro‐metastatic CAF subsets in cervical squamous cell carcinoma (CSCC) remain unknown. Here, we describe a CAF subpopulation with elevated periostin expression (periostin⁺CAFs), located in the primary tumor sites and metastatic lymph nodes, that positively correlated with LNM and poor survival in CSCC patients. Mechanistically, periostin⁺CAFs impaired lymphatic endothelial barriers by activating the integrin‐FAK/Src‐VE‐cadherin signaling pathway in lymphatic endothelial cells and consequently enhanced metastatic dissemination. In contrast, inhibition of the FAK/Src signaling pathway alleviated periostin‐induced lymphatic endothelial barrier dysfunction and its related effects. Notably, periostin^‐CAFs were incapable of impairing endothelial barrier integrity, which may explain the occurrence of CAF‐enriched cases without LNM. In conclusion, we identified a specific periostin⁺CAF subset that promotes LNM in CSCC, mainly by impairing the lymphatic endothelial barriers, thus providing the basis for potential stromal fibroblast‐targeted interventions that block CAF‐dependent metastasis.

The Tumor Microenvironment: Focus on Extracellular Matrix

The extracellular matrix (ECM) regulates the development and maintains tissue homeostasis. The ECM is composed of a complex network of molecules presenting distinct biochemical properties to regulate cell growth, survival, motility, and differentiation. Among their components, proteoglycans (PGs) are considered one of the main components of ECM. Its composition, biomechanics, and anisotropy are exquisitely tuned to reflect the physiological state of the tissue. The loss of ECM's homeostasis is seen as one of the hallmarks of cancer and, typically, defines transitional events in tumor progression and metastasis. In this chapter, we discuss the types of proteoglycans and their roles in cancer. It has been observed that the amount of some ECM components is increased, while others are decreased, depending on the type of tumor. However, both conditions corroborate with tumor progression and malignancy. Therefore, ECM components have an increasingly important role in carcinogenesis and this leads us to believe that their understanding may be a key in the discovery of new anti-tumor therapies. In this book, the main ECM components will be discussed in more detail in each chapter.

Tumor dormancy as an alternative step in the development of chemoresistance and metastasis - clinical implications

BACKGROUND

The ability of a tumor to become dormant in response to suboptimal conditions has recently been recognized as a key step in tumor progression. Tumor dormancy has been found to be implicated in several tumor types as the culprit of therapy resistance and metastasis development, the deadliest features of a cancer. Several lines of evidence indicate that the development of these traits may rely on the de-differentiation of committed tumor cells that regain stem-like properties during a dormant state. Presently, dormancy is classified into cell- and population-level, according to the preponderance of cellular mechanisms that keep tumor cells quiescent or to a balance between overall cell division and death, respectively. Cellular dormancy is characterized by autophagy, stress-tolerance signaling, microenvironmental cues and, of prime relevance, epigenetic modifications. It has been found that the epigenome alters during cellular quiescence, thus representing the driving force for short-term cancer progression. Population-level dormancy is characterized by processes that counteract proliferation, such as inappropriate blood supply and intense immune responses. The latter two mechanisms are not mutually exclusive and may affect tumor masses both simultaneously and subsequently.

CONCLUSIONS

Overall, tumor dormancy may represent an additional step in the acquisition of cancer characteristics, and its comprehension may clarify both theoretical and practical aspects of cancer development. Clinically, only a deep understanding of dormancy may explain the course of tumor development in different patients, thus representing a process that may be targeted to prevent and/or treat advanced-stage cancers. That is especially the case for breast cancer, against which the mTOR inhibitor everolimus displays potent antitumor activity in patients with metastatic disease by impeding autophagy and tumor dormancy onset. Here we will also discuss other targeted therapies directed towards tumor dormancy onset, e.g. specific inhibitors of SFK and MEK, or aimed at keeping tumor cells dormant, e.g. prosaposin derivatives, that may shortly enter clinical assessment in breast, and possibly other cancer types.

Are Integrins Still Practicable Targets for Anti-Cancer Therapy?

Correlative clinical evidence and experimental observations indicate that integrin adhesion receptors, in particular those of the αV family, are relevant to cancer cell features, including proliferation, survival, migration, invasion, and metastasis. In addition, integrins promote events in the tumor microenvironment that are critical for tumor progression and metastasis, including tumor angiogenesis, matrix remodeling, and the recruitment of immune and inflammatory cells. In spite of compelling preclinical results demonstrating that the inhibition of integrin αVβ3/αVβ5 and α5β1 has therapeutic potential, clinical trials with integrin inhibitors targeting those integrins have repeatedly failed to demonstrate therapeutic benefits in cancer patients. Here, we review emerging integrin functions and their proposed contribution to tumor progression, discuss preclinical evidence of therapeutic significance, revisit clinical trial results, and consider alternative approaches for their therapeutic targeting in oncology, including targeting integrins in the other cells of the tumor microenvironment, e.g., cancer-associated fibroblasts and immune/inflammatory cells. We conclude that integrins remain a valid target for cancer therapy; however, agents with better pharmacological properties, alternative models for their preclinical evaluation, and innovative combination strategies for clinical testing (e.g., together with immuno-oncology agents) are needed.

Overexpression of periostin is positively associated with gastric cancer metastasis through promoting tumor metastasis and invasion

BACKGROUND

Gastric tumors generally have a poor prognosis and molecular markers to improve early detection and predict outcomes are greatly needed. The present study reports that periostin (POSTN), a secretory protein that can alter the remodeling of the extracellular matrix, is highly expressed in gastric tumors.

MATERIALS AND METHODS

Gastric tissues were collected from patients at the Department of Thoracic Surgery/Huiqiao Medical Center, Nanfang Hospital, Southern Medical University. These patients provided an informed consent and were approved by the institute. Normal, cancer, and metastatic gastric tissues from lymph nodes and tissues adjacent to the tumor were collected from patients diagnosed with gastric cancer.

RESULTS

Periostin expression gradually increased as the risk grade of the NIH classification increased, and this was closely correlated with disease-free survival and overall survival. Compared with adjacent normal gastric mucosa tissues, protein expression of POSTN in gastric cancer tissues and metastases was significantly higher by immunohistochemistry and Western blot analysis. In addition, POSTN was upregulated in advanced gastric cancer tissues than in early gastric cancer tissues. Moreover, the ectopic expression of POSTN in the immortalized human gastric cell line could increase the metastasis and invasion of gastric cancer cells.

CONCLUSION

The present results could establish the significance of POSTN in driving oncogenesis and metastasis in gastric tumors, with implications for its potential use as a diagnostic or prognostic biomarker, and as a candidate therapeutic target.

Assessing the efficacy of androgen receptor and Sox10 as independent markers of the triple-negative breast cancer subtype by transcriptome profiling

The Androgen Receptor (AR) has recently garnered a lot of attention as a potential biomarker and therapeutic target in hormone-dependent cancers, including breast cancer. However, several inconsistencies exist within the literature as to which subtypes of breast cancer express AR or whether it can be used to define its own unique subtype. Here, we analyze 1246 invasive breast cancer samples from the Cancer Genome Atlas and show that human breast cancers that have been subtyped based on their HER2, ESR1, or PGR expression contain four clusters of genes that are differentially expressed across all subtypes. We demonstrate that Sox10 is highly expressed in approximately one-third of all HER2/ESR1/PGR-low tumors and is a candidate biomarker of the triple-negative subtype. Although AR expression is acquired in many breast cancer cases, its expression could not define a unique subtype. Despite several reports stating that AR expression is acquired in HER2/ESR1/PGR triple-negative cancers, here we show that a low percentage of these cancers express AR (~20%). In contrast, AR is highly expressed in HER2-positive or ESR1/PGR-positive cancers (> 95%). Although AR expression cannot be used as an independent subtype biomarker, our analysis shows that routine evaluation of AR expression in tumors which express HER2, ESR1 and/or PGR may identify a unique subset of tumors which would benefit from anti-androgen based therapies.

Periostin and CA242 as potential diagnostic serum biomarkers complementing CA19.9 in detecting pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with few biomarkers to guide treatment options. Carbohydrate antigen 19.9 (CA19.9), the most frequently used biomarker for PDAC, is not sensitive and specific enough for the detection of the disease. This study aimed to evaluate serum periostin (POSTN) and CA242 as potential diagnostic biomarkers complementing CA19.9 in detecting pancreatic cancer. Blood samples were from 362 participants, including 213 patients with different stages of PDAC, 75 patients with benign pancreatic disease, and 74 healthy individuals. All samples were randomly divided into a training set and a validation set. Carbohydrate antigen 19.9, CA242, POSTN, as well as carcinoembryonic antigen, were measured by ELISA or automated immunoassay. The receiver operating characteristic curve analysis revealed that the performance of CA19.9 in the validation group were improved by the marker panel composed of CA19.9, POSTN, and CA242, to discriminate early stage PDAC not only from healthy controls (area under the curve [AUC]CA19.9 = 0.94 vs AUCCA19.9 + POSTN + CA242 = 0.98, P < .05) but also from benign conditions (AUCCA19.9 = 0.87 vs AUCCA19.9 + POSTN + CA242 = 0.90, P < .05). In addition, POSTN retained significant diagnostic capabilities to distinguish PDAC CA19.9-negative from healthy controls (AUCPOSTN = 0.87) as well as from benign conditions (AUCPOSTN = 0.84) in the whole set. This study suggested that POSTN and CA242 are potential diagnostic serum biomarkers complementing CA19.9 in detecting early pancreatic cancer.

Effects of the Notch1 signaling pathway on human lung cancer A549 cells

PURPOSE

To evaluate the effects of the Notch1 signaling pathway on human lung cancer A549 cells.

MATERIALS AND METHODS

A549 cells were transfected with recombinant plasmids. Cell proliferation was detected by MTT assay. A tumor-bearing mouse model was established for intratumoral gene injection. Apoptosis-related factors were detected by immunohistochemical assay. Caspase-8, caspase-3, caspase-9, PI3K, pAkt and pSTAT3 expressions were detected by Western blotting.

RESULTS

Compared with A549-GFP and A549 cells, A549-ICN cell growth in mice decelerated, tumor volume significantly reduced (p < 0.01), and survival time significantly increased (p < 0.05). Cyclin E and phosphorylated Rb protein expressions were significantly down-regulated. Compared with control, apoptosis-related protein Bcl-2 expression in tumors injected with Notch1 gene was significantly inhibited. After Deltex1 transfection, A549 cell proliferation decelerated, growth was significantly inhibited (p < 0.05), and survival time was significantly extended (p < 0.05). Cyclin E and mutant p53 protein expressions in tumors were down-regulated, phosphorylated Rb expression was almost completely inhibited, and Bcl-2 expression was significantly inhibited. TNF-α-related apoptosis-inducing ligand (TRAIL) inhibited A549-ICN cell growth time- and dose-dependently. After treatment for 24 h or longer, TRAIL induced apoptosis of more A549-ICN cells. Cleaved caspase-3 and cleaved caspase-9 were detected only in A549-ICN cells after 6 h of 40 ng/mL TRAIL treatment, but cleaved caspase-8 was not detected. Combining Notch1 signal with TRAIL inhibited PI3K, phosphorylated Akt and phosphorylated STAT3 expressions.

CONCLUSION

The Notch1 signaling pathway may inhibit A549 cell growth in vitro and in vivo by regulating cell cycle-related and anti-apoptotic protein expressions. Notch1 activation also suppressed A549 cell apoptosis by inhibiting the PI3K/pAkt pathway and activating the caspase-3 pathway in cooperation with TRAIL.

Molecular Portrait of the Normal Human Breast Tissue and Its Influence on Breast Carcinogenesis

Normal human breast tissue consists of epithelial and nonepithelial cells with different molecular profiles and differentiation grades. This molecular heterogeneity is known to yield abnormal clones that may contribute to the development of breast carcinomas. Stem cells that are found in developing and mature breast tissue are either positive or negative for cytokeratin 19 depending on their subtype. These cells are able to generate carcinogenesis along with mature cells. However, scientific data remains controversial regarding the monoclonal or polyclonal origin of breast carcinomas. The majority of breast carcinomas originate from epithelial cells that normally express BRCA1. The consecutive loss of the BRCA1 gene leads to various abnormalities in epithelial cells. Normal breast epithelial cells also express hypoxia inducible factor (HIF) 1α and HIF-2α that are associated with a high metastatic rate and a poor prognosis for malignant lesions. The nuclear expression of estrogen receptor (ER) and progesterone receptor (PR) in normal human breast tissue is maintained in malignant tissue as well. Several controversies regarding the ability of ER and PR status to predict breast cancer outcome remain. Both ER and PR act as modulators of cell activity in normal human breast tissue. Ki-67 positivity is strongly correlated with tumor grade although its specific role in applied therapy requires further studies. Human epidermal growth factor receptor 2 (HER2) oncoprotein is less expressed in normal human breast specimens but is highly expressed in certain malignant lesions of the breast. Unlike HER2, epidermal growth factor receptor expression is similar in both normal and malignant tissues. Molecular heterogeneity is not only found in breast carcinomas but also in normal breast tissue. Therefore, the molecular mapping of normal human breast tissue might represent a key research area to fully elucidate the mechanisms of breast carcinogenesis.

Role of periostin in esophageal, gastric and colon cancer

Periostin, also known as osteoblast-specific factor 2, is a cell-adhesion protein with pleiotropic properties. The protein serves a vital role in the maintenance and development of tooth and bone tissue, in addition to cardiac development and healing. Periostin levels are increased in several forms of cancer, including pancreatic, ovarian, colon, lung, breast, gastric, thyroid, and esophageal head and neck carcinomas. The present review highlights the key role of periostin in tumorigenesis, particularly in increasing cell survival, invasion, angiogenesis, epithelial-mesenchymal transition and metastasis of carcinoma cells by interacting with numerous cell-surface receptors, including integrins, in the phosphoinositide 3-kinase-Akt pathway. In addition, periostin actively affects the canonical Wnt signaling pathway of colorectal tumorigenesis. The current review focused on the involvement of periostin in the development of colorectal, esophageal and gastric cancer.

The extracellular matrix in breast cancer

The extracellular matrix (ECM) is increasingly recognized as an important regulator in breast cancer. ECM in breast cancer development features numerous changes in composition and organization when compared to the mammary gland under homeostasis. Matrix proteins that are induced in breast cancer include fibrillar collagens, fibronectin, specific laminins and proteoglycans as well as matricellular proteins. Growing evidence suggests that many of these induced ECM proteins play a major functional role in breast cancer progression and metastasis. A number of the induced ECM proteins have moreover been shown to be essential components of metastatic niches, promoting stem/progenitor signaling pathways and metastatic growth. ECM remodeling enzymes are also markedly increased, leading to major changes in the matrix structure and biomechanical properties. Importantly, several ECM components and ECM remodeling enzymes are specifically induced in breast cancer or during tissue regeneration while healthy tissues under homeostasis express exceedingly low levels. This may indicate that ECM and ECM-associated functions may represent promising drug targets against breast cancer, providing important specificity that could be utilized when developing therapies.