Triple-threat activity of PEDF in bone tumors: Tumor inhibition, tissue preservation and cardioprotection against doxorubicin

The comparison of pathogenic role and mechanism of Kallistatin and PEDF in tumors

Tumors are diseases caused by abnormal cell division and growth, which can be life-threatening if not treated properly. Serpin inhibitors play a crucial role in regulating pathophysiological process and are promising drug targets. Kallistatin (SERPINA4) and Pigment Epithelium-Derived Factor (PEDF, SERPINF1) are two serpins that lack protease inhibitory activity but are abundant in blood. They exhibit anti-angiogenic effects and are involved in tumorigenesis. The pathogenic role and mechanism of Kallistatin and pigment epithelium-derived factor (PEDF) have been extensively studied for their potential use in cancer therapy. Kallistatin and PEDF play significant roles in controlling tumor growth and progression. While they share some common mechanisms of action, such as promoting apoptosis and inhibiting angiogenesis, they also have distinct differences in effectiveness and range of anti-tumor activities. This review compares and contrasts the expression patterns, structural features, expression regulation, disease roles, signaling pathways, and potential clinical value of Kallistatin and PEDF, aiming to provide a comprehensive understanding of their biomedical and clinical potential.

Prevention of chemotherapy-related bone loss with doxorubicin-loaded solid lipid nanoparticles

Aim: Breast cancer and its metastases involve high mortality even with advances in chemotherapy. Solid lipid nanoparticles provide a platform for drug delivery, reducing side effects and treatment-induced bone loss. A solid nanoparticle containing doxorubicin was evaluated for its ability to prevent bone loss in a pre-clinical breast cancer model.Methods: We investigated the effects of SLNDox in an aggressive metastatic stage IV breast cancer model, which has some important features that are interesting for bone loss investigation. This study evaluates bone loss prevention potential from solid lipid nanoparticles containing doxorubicin breast cancer treatment, an evaluation of the attenuation of morphological changes in bone tissue caused by the treatment and the disease and an assessment of bone loss imaging using computed tomography and electron microscopy.Results: Chemotherapy-induced bone loss was also observed in tumor-free animals; a solid lipid nanoparticle containing doxorubicin prevented damage to the growth plate and to compact and cancellous bones in the femur of tumor-bearing and healthy animals.Conclusion: The association of solid lipid nanoparticles with chemotherapeutic drugs with proven efficacy promotes the prevention of serious consequences of chemotherapy, reducing tumor progression, increasing quality of life and improving prognosis and survival.

Effects of Doxorubicin, Epirubicin, and Liposomal Doxorubicin (Anthracycline) on cardiac function in patients with osteosarcoma and their influencing factors

OBJECTIVE

The objective of this study was to investigate the impact of Doxorubicin, Epirubicin, and Liposomal Doxorubicin (Anthracycline) on cardiac function in osteosarcoma patients and analyze the factors influencing this effect.

METHODS

A retrospective study was conducted on 165 osteosarcoma patients admitted to our hospital from January 2020 to December 2022. Based on the chemotherapy regimen, the patients were divided into two groups: the control group (n = 62) treated with Cisplatin and cyclophosphamide, and the observation group (n = 103) treated with Doxorubicin, Epirubicin, and Liposomal Doxorubicin (Anthracycline). The general records of both groups were analyzed, and left ventricular ejection fraction (LVEF) was evaluated through echocardiography before and after chemotherapy. Blood cTnT and CK-MB levels were measured using immunoluminescence. The incidence of adverse reactions during chemotherapy was also analyzed. Univariate analysis was performed to identify patients with cardiotoxic events, and multiple logistic regression analysis was done to study the effects of Doxorubicin, Epirubicin, Liposomal Doxorubicin, and their dosages on cardiotoxicity in patients.

RESULTS

The general records between the two groups showed no significant differences (P > 0.05). However, at the fourth cycle of chemotherapy, the observation group exhibited a lower LVEF (P < 0.05), and a higher percentage of LVEF decrease compared to the control group (P < 0.05). Moreover, the observation group had higher levels of blood cTnT and CK-MB (P < 0.05). The incidence of cardiotoxicity in the observation group was also higher (P < 0.05), but no significant differences were seen in other adverse reaction rates (P > 0.05). The occurrence of cardiotoxicity was found to be related to the choice and dosage of chemotherapy drugs (P < 0.05), but not significantly correlated with age, sex, and mediastinal irradiation in patients (P > 0.05). Furthermore, the use of Doxorubicin, Epirubicin, and Liposomal Doxorubicin in chemotherapy, as well as an increase in their dosages, was found to elevate the risk of cardiotoxicity in osteosarcoma patients (P < 0.05). However, age, sex, and mediastinal radiation were not significantly associated with cardiotoxicity in osteosarcoma patients (P > 0.05).

CONCLUSION

We demonstrated that Doxorubicin, Epirubicin, Liposomal Doxorubicin (Anthracycline), and other drugs adversely affected cardiac function in osteosarcoma patients, increasing the risk of cardiac toxicity. Therefore, close monitoring of cardiac function during chemotherapy is crucial, and timely adjustments to the chemotherapy regimen are necessary. In addition, rational control of drug selection and dosage is essential to minimize the occurrence of cardiac toxicity.

Circulating biomarkers in perioperative management of cancer patients

Owing to the advances in surgical technology, most solid tumours can be controlled by surgical excision. The priority should be tumour control, while some routine perioperative management might influence cancer progression in an unnoticed way. Moreover, it is increasingly recognized that effective perioperative management should include techniques to improve postoperative outcomes. These influences are elucidated by the different functions of circulating biomarkers in cancer patients. Here, circulating biomarkers with two types of clinical functions were reviewed: (i) circulating biomarkers for cancer progression monitoring, for instance, those related to cancer cell malignancy, tumour microenvironment formation, and early metastasis, and (ii) circulating biomarkers with relevance to postoperative outcomes, including systemic inflammation, immunosuppression, cognitive dysfunction, and pain management. This review aimed to provide new perspectives for the perioperative management of patients with cancer and highlight the potential clinical translation value of circulating biomarkers in improving outcomes.

Pigment Epithelium-Derived Factor: Inhibition of Phosphorylation of Insulin Receptor (IR)/IR Substrate (IRS), Osteogeneration from Adipocytes, and Increased Levels Due to Doxorubicin Exposure

OBJECTIVES

Pigment epithelium-derived factor (PEDF) has been recently linked to insulin resistance and is capable of differentiating myocytes to bone. We examined in more detail the intricate signalling of the insulin pathway influenced by PEDF in skeletal myocytes. We tested whether this serpin is also capable of generating de novo bone from adipocytes in vitro and in vivo, and how the anticancer drug doxorubicin links with PEDF and cellular metabolism.

METHODS AND KEY FINDINGS

We demonstrate that PEDF can inhibit phosphorylation of insulin receptor (IR) and insulin receptor substrate (IRS) in skeletal myocytes. PEDF constitutively activates p42/44 MAPK/Erk, but paradoxically does not affect mitogenic signalling. PEDF did not perturb either mitochondrial activity or proliferation in cells representing mesenchymal stem cells, cardiomyocytes, and skeletal myocytes and adipocytes. PEDF induced transdifferentiation of adipocytes to osteoblasts, promoting bone formation in cultured adipocytes in vitro and gelfoam fatpad implants in vivo. Bone formation in white adipose tissue (WAT) was better than in brown adipose tissue (BAT). The frontline anticancer drug doxorubicin increased levels of PEDF in a human breast cancer cell line, mirroring the in vivo finding where cardiac muscle tissue was stained increasingly for PEDF as the dose of doxorubicin increased in mice. PEDF also increased levels of reactive oxygen species (ROS) and glutathione (GSH) in the breast cancer cell line.

CONCLUSIONS

PEDF may be used to regenerate bone from adipose tissue in cases of trauma such as fractures or bone cancers. The increased presence of PEDF in doxorubicin-treated tumour cells need further exploration, and could be useful therapeutically in future. The safety of PEDF administration in vivo was further demonstrated in this study.

Potential therapeutic role for pigment epithelium-derived factor in post-menopausal breast cancer bone metastasis

OBJECTIVES

This review discusses key oestrogens associated with the circulating pre- and post-menopausal milieu and how they may impact intratumoral oestrogen levels and breast cancer (BC) metastasis. It also identifies critical steps in BC metastasis to bone from the viewpoint of pigment epithelium-derived factor (PEDF) function, and discusses the role of several associated pro-metastatic biomarkers in BC bone metastasis.

KEY FINDINGS

PEDF is regulated by oestrogen in a number of oestrogen-sensitive tissues. Changes in circulating oestrogen levels associated with menopause may enhance the growth of BC bone metastases, leading to the establishment of a pre-metastatic niche. The establishment of such a pre-metastatic niche is driven by several key mediators, with pro-osteoclastic and pro-metastatic function which are upregulated by BC cells. These mediators appear to be regulated by oestrogen, as well as differentially affected by menopausal status. PEDF interacts with several pro-metastatic, pro-osteoclastic biomarkers, including C-X-C motif chemokine receptor 4 (CXCR4) and nuclear factor kappa B (NFκB) in BC bone metastasis.

CONCLUSION

Mediators such as CXCR4 and MT1-MMP underpin the ability of PEDF to function as an antimetastatic in other cancers such as osteosarcoma, highlighting the possibility that this serpin could be used as a therapeutic against BC metastasis in future.

Roles of pigment epithelium-derived factor in cardiomyocytes: implications for use as a cardioprotective therapeutic

OBJECTIVES

Cardiovascular diseases are the leading cause of death worldwide, with patients having limited options for treatment. Pigment epithelium-derived factor (PEDF) is an endogenous multifunctional protein with several mechanisms of action. Recently, PEDF has emerged as a potential cardioprotective agent in response to myocardial infarction. However, PEDF is also associated with pro-apoptotic effects, complicating its role in cardioprotection. This review summarises and compares knowledge of PEDF's activity in cardiomyocytes with other cell types and draws links between them. Following this, the review offers a novel perspective of PEDF's therapeutic potential and recommends future directions to understand the clinical potential of PEDF better.

KEY FINDINGS

PEDF's mechanisms as a pro-apoptotic and pro-survival protein are not well understood, despite PEDF's implication in several physiological and pathological activities. However, recent evidence suggests that PEDF may have significant cardioprotective properties mediated by key regulators dependent on cell type and context.

CONCLUSIONS

While PEDF's cardioprotective activity shares some key regulators with its apoptotic activity, cellular context and molecular features likely allow manipulation of PEDF's cellular activity, highlighting the importance of further investigation into its activities and its potential to be applied as a therapeutic to mitigate damage from a range of cardiac pathologies.

Pigment epithelium-derived factor downregulation in oestrogen receptor positive breast cancer bone metastases is associated with menopause

Pigment epithelium-derived factor (PEDF) has a critical role in bone development and anti-tumour function in breast cancer (BC). As the expression and role of PEDF in BC bone metastases is unknown, we aimed to characterise PEDF in primary and metastatic BC. Subcellular PEDF localisation was semi-quantitatively analysed via immunohistochemistry in patient-matched, archived formalin-fixed paraffin-embedded primary BC and liver, lung, and decalcified bone metastases specimens. PEDF localisation was evaluated in 23 metastatic BC patients diagnosed with ER+, human epidermal growth factor receptor-2 (HER2) negative BC or TNBC. Cytoplasmic (p = 0.019) and membrane (p = 0.048) PEDF was lower in bone metastases compared to primary ER+/HER2- BC. In contrast, nuclear PEDF scores were higher in metastases compared to primary TNBC (p = 0.027), and increased membrane PEDF in metastatic tissue had improved disease-free interval (p = 0.016). Nuclear PEDF was decreased in bone metastases compared to primary ER+//HER2- BC in post-menopausal patients (p = 0.029). These novel findings indicate PEDF plays a role in clinical BC metastasis. Significantly lower PEDF levels in the post-menopausal compared to pre-menopausal setting suggests future PEDF research may have greater clinical importance in the post-menopausal ER+/HER2- BC population.

Doxorubicin-induced cardiotoxicity: causative factors and possible interventions

OBJECTIVES

Doxorubicin (Dox) belongs to the anthracycline drug classification and is a widely administered chemotherapeutic. However, Dox use in therapy is limited by its cardiotoxicity, representing a significant drawback of Dox treatment applicability. A large amount of current research is on reducing Dox-induced cardiotoxicity by developing targeted delivery systems and investigating cardiotoxicity mechanisms. Recently, discrepancies have challenged the traditional understanding of Dox metabolism, mechanisms of action and cardiotoxicity drivers. This review summarises the current knowledge around Dox's metabolism, mechanisms of anticancer activity, and delivery systems and offers a unique perspective on the relationships between several proposed mechanisms of Dox-induced cardiotoxicity.

KEY FINDINGS

While there is a strong understanding of Dox's pharmacokinetic properties, it is unclear which enzymes contribute to Dox metabolism and how Dox induces its cytotoxic effect in neoplastic and non-neoplastic cells. Evidence suggests that there are several potentially synergistic mechanisms involved in Dox-induced cardiotoxicity.

SUMMARY

It has become clear that Dox operates in a multifactorial fashion dependent on cellular context. Accumulation of oxidative stress appears to be a common factor in cardiotoxicity mechanisms, highlighting the importance of novel delivery systems and antioxidant therapies.

The increasing role of pigment epithelium-derived factor in metastasis: from biological importance to a promising target

Pigment epithelium-derived factor (PEDF) is a non-inhibitory member of the serpin (serine protease inhibitor) family and is a well-known potent anti-tumor factor in a variety of cancers. It has been ascertained that PEDF regulates multiple metastatic processes through various plausible mechanisms, including inhibiting angiogenesis, inducing apoptosis, stimulating extracellular matrix (ECM) degradation, and suppressing the epithelial-to-mesenchymal transition (EMT) process. Although PEDF has been recognized as an anti-metastatic marker in most studies, its role remains controversial with conflicting reports of PEDF as a metastatic marker. The emerging insights into the mechanism(s) of PEDF in tumor progression and its therapeutic effects are discussed systematically in this review, aiming to improve our understanding in the context of metastasis and drug development.

Lung but not brain cancer cell malignancy inhibited by commonly used anesthetic propofol during surgery: Implication of reducing cancer recurrence risk

Introduction

Intravenous anesthesia with propofol was reported to improve cancer surgical outcomes when compared with inhalational anesthesia. However, the underlying molecular mechanisms largely remain unknown.

Objectives

The anti-tumor effects of propofol and the possible underlying mechanism including altered metabolic and signaling pathways were studied in the current study.

Methods

The cell viability, proliferation, migration, and invasion of cancer cells were analyzed with CCK-8, Ki-67 staining, wound healing, and Transwell assay, respectively. The protein changes were analyzed with Western blot and immunofluorescent staining. The metabolomics alteration was studied with 1H-NMR spectroscopy. The gene expression regulations were analyzed with PCR gene array and qRT-PCR experiments.

Results

In this study, we found that propofol reduced cell viability and inhibited cell proliferation, migration and invasion of lung cancer cells, but not neuroglioma cells. In lung cancer cells, propofol downregulated glucose transporter 1 (GLUT1), mitochondrial pyruvate carrier 1 (MPC1), p-Akt, p-Erk1/2, and hypoxia- inducible factor 1 alpha (HIF-1 α ) expressions and upregulated pigment epithelium-derived factor (PEDF) expression. Propofol increased intracellular glutamate and glycine but decreased acetate and formate whilst increased glucose, lactate, glutamine, succinate, pyruvate, arginine, valine, isoleucine, and leucine and glycerol, and decreased acetate, ethanol, isopropanol in the culture media of lung cancer cells. Furthermore, VEGFA, CTBP1, CST7, CTSK, CXCL12, and CXCR4 gene expressions were downregulated, while NR4A3, RB1, NME1, MTSS1, NME4, SYK, APC, and FAT1 were upregulated following the propofol treatment. Consistent with the phenotypical changes, these molecular and metabolic changes were not found in the neuroglioma cells.

Conclusion

Our findings indicated anti-tumor effects of propofol on the lung cancer but not brain cancer, through the regulation of tumor metastasis-related genes, multi-cellular signaling and cellular metabolism.

Pigment Epithelium-Derived Factor and Sex Hormone-Responsive Cancers

Oestrogens and androgens play important roles in normal and cancerous tissue and have been shown to negatively regulate pigment epithelium-derived factor (PEDF) expression in sex hormone-responsive tumours. PEDF suppresses tumour growth and its downregulation by oestrogen is implicated in tumorigenesis, metastasis, and progression. PEDF expression is reduced in cancerous tissue of the prostate, breast, ovary, and endometrium compared to their normal tissue counterparts, with a link between PEDF downregulation and sex hormone signalling observed in pre-clinical studies. PEDF reduces growth and metastasis of tumour cells by promoting apoptosis, inhibiting angiogenesis, increasing adhesion, and reducing migration. PEDF may also prevent treatment resistance in some cancers by downregulating oestrogen receptor signalling. By interacting with components of the tumour microenvironment, PEDF counteracts the proliferative and immunosuppressive effects of oestrogens, to ultimately reduce tumorigenesis and metastasis. In this review, we focus on sex hormone regulation of PEDF's anti-tumour action in sex hormone-responsive tumours.