Osteopontin isoform c promotes the survival of cisplatin-treated NSCLC cells involving NFATc2-mediated suppression on calcium-induced ROS levels

Identification of protein biomarkers associated with congenital diaphragmatic hernia in human amniotic fluid

Congenital diaphragmatic hernia (CDH) is a severe birth defect frequently associated with pulmonary hypoplasia, pulmonary hypertension, and heart failure. Since amniotic fluid comprises proteins of both fetal and maternal origin, its analysis could provide insights on mechanisms underlying CDH and provide biomarkers for early diagnosis, severity of pulmonary changes and treatment response. The study objective was to identify proteomic changes in amniotic fluid consistently associated with CDH. Amniotic fluid was obtained at term (37-39 weeks) from women with normal pregnancies (n = 5) or carrying fetuses with CDH (n = 5). After immuno-depletion of the highest abundance proteins, off-line fractionation and high-resolution tandem mass spectrometry were performed and quantitative differences between the proteomes of the groups were determined. Of 1036 proteins identified, 218 were differentially abundant. Bioinformatics analysis showed significant changes in GP6 signaling, in the MSP-RON signaling in macrophages pathway and in networks associated with cardiovascular system development and function, connective tissue disorders and dermatological conditions. Differences in selected proteins, namely pulmonary surfactant protein B, osteopontin, kallikrein 5 and galectin-3 were validated by orthogonal testing using ELISA in larger cohorts and showed statistically significant differences aiding in the diagnosis and prediction of CDH. The findings provide potential tools for clinical management of CDH.

Osteopontin as a Biomarker in Chronic Kidney Disease

Osteopontin (OPN) is a ubiquitously expressed protein with a wide range of physiological functions, including roles in bone mineralization, immune regulation, and wound healing. OPN has been implicated in the pathogenesis of several forms of chronic kidney disease (CKD) where it promotes inflammation and fibrosis and regulates calcium and phosphate metabolism. OPN expression is increased in the kidneys, blood, and urine of patients with CKD, particularly in those with diabetic kidney disease and glomerulonephritis. The full-length OPN protein is cleaved by various proteases, including thrombin, matrix metalloproteinase (MMP)-3, MMP-7, cathepsin-D, and plasmin, producing N-terminal OPN (ntOPN), which may have more detrimental effects in CKD. Studies suggest that OPN may serve as a biomarker in CKD, and while more research is needed to fully evaluate and validate OPN and ntOPN as CKD biomarkers, the available evidence suggests that they are promising candidates for further investigation. Targeting OPN may be a potential treatment strategy. Several studies show that inhibition of OPN expression or activity can attenuate kidney injury and improve kidney function. In addition to its effects on kidney function, OPN has been linked to cardiovascular disease, which is a major cause of morbidity and mortality in patients with CKD.

Meta-analysis of Osteopontin splice variants in cancer

BACKGROUND

The cytokine Osteopontin is a mediator of tumor progression and cancer metastasis. In 2006, we reported that (in addition to the full-length form -a) splice variants of Osteopontin (forms -b and -c) are produced selectively by transformed cells. Through June 2021, 36 PubMed-indexed journal articles have studied Osteopontin splice variants in various cancer patients.

METHODS

Applying a categorical approach previously developed by us, here we conduct a meta-analysis of the pertinent literature. We supplement this with evaluation of the relevant entries in the TSVdb database, which focusses on splice variant expression, thus including the additional variants -4 and -5. The analysis covers 5886 patients across 15 tumors from the literature and 10,446 patients across 33 tumors from TSVdb.

RESULTS

The database yields positive results more frequently than the categorical meta-analysis. The two sources are in agreement on the elevation of OPN-a, OPN-b, and OPN-c in lung cancer and the elevation of OPN-c in breast cancer as compared to healthy tissue. Specific splice variants are associated with grade, stage, or patient survival pertaining to various cancers.

CONCLUSIONS

There are cases of persisting discrepancies, which require further investigation to clarify the Osteopontin splice variant utilization, so that their diagnostic, prognostic and potentially predictive potential can be brought to fruition.

Chromatin and Cancer: Implications of Disrupted Chromatin Organization in Tumorigenesis and Its Diversification

A hallmark of cancers is uncontrolled cell proliferation, frequently associated with an underlying imbalance in gene expression. This transcriptional dysregulation observed in cancers is multifaceted and involves chromosomal rearrangements, chimeric transcription factors, or altered epigenetic marks. Traditionally, chromatin dysregulation in cancers has been considered a downstream effect of driver mutations. However, here we present a broader perspective on the alteration of chromatin organization in the establishment, diversification, and therapeutic resistance of cancers. We hypothesize that the chromatin organization controls the accessibility of the transcriptional machinery to regulate gene expression in cancerous cells and preserves the structural integrity of the nucleus by regulating nuclear volume. Disruption of this large-scale chromatin in proliferating cancerous cells in conventional chemotherapies induces DNA damage and provides a positive feedback loop for chromatin rearrangements and tumor diversification. Consequently, the surviving cells from these chemotherapies become tolerant to higher doses of the therapeutic reagents, which are significantly toxic to normal cells. Furthermore, the disorganization of chromatin induced by these therapies accentuates nuclear fragility, thereby increasing the invasive potential of these tumors. Therefore, we believe that understanding the changes in chromatin organization in cancerous cells is expected to deliver more effective pharmacological interventions with minimal effects on non-cancerous cells.

Periostin Augments Vascular Smooth Muscle Cell Calcification via β-Catenin Signaling

Medial vascular calcification is common in chronic kidney disease (CKD) and is closely linked to hyperphosphatemia. Vascular smooth muscle cells (VSMCs) can take up pro-calcific properties and actively augment vascular calcification. Various pro-inflammatory mediators are able to promote VSMC calcification. In this study, we investigated the effects and mechanisms of periostin, a matricellular signaling protein, in calcifying human VSMCs and human serum samples. As a result, periostin induced the mRNA expression of pro-calcific markers in VSMCs. Furthermore, periostin augmented the effects of β-glycerophosphate on the expression of pro-calcific markers and aggravated the calcification of VSMCs. A periostin treatment was associated with an increased β-catenin abundance as well as the expression of target genes. The pro-calcific effects of periostin were ameliorated by WNT/β-catenin pathway inhibitors. Moreover, a co-treatment with an integrin αvβ3-blocking antibody blunted the pro-calcific effects of periostin. The silencing of periostin reduced the effects of β-glycerophosphate on the expression of pro-calcific markers and the calcification of VSMCs. Elevated serum periostin levels were observed in hemodialysis patients compared with healthy controls. These observations identified periostin as an augmentative factor in VSMC calcification. The pro-calcific effects of periostin involve integrin αvβ3 and the activation of the WNT/β-catenin pathway. Thus, the inhibition of periostin may be beneficial to reduce the burden of vascular calcification in CKD patients.