Identification of GRP78 as a molecular target of medicarpin in osteoblast cells by proteomics

MicroRNA-495: a therapeutic and diagnostic tumor marker

Therapeutic and diagnostic progresses have significantly reduced the mortality rate among cancer patients during the last decade. However, there is still a high rate of mortality among cancer patients. One of the important reasons involved in the high mortality rate is the late diagnosis in advanced tumor stages that causes the failure of therapeutic strategies in these patients. Therefore, investigating the molecular mechanisms involved in tumor progression has an important role in introducing the efficient early detection markers. MicroRNAs (miRNAs) as stable factors in body fluids are always considered as non-invasive diagnostic and prognostic markers. In the present review, we investigated the role of miR-495 in tumor progression. It has been reported that miR-495 has mainly a tumor suppressor function through the regulation of transcription factors and tyrosine kinases as well as cellular processes such as multidrug resistance, chromatin remodeling, and signaling pathways. This review can be an effective step towards introducing the miR-495 as a non-invasive diagnostic/prognostic marker as well as a suitable target in tumor therapy.

A novel mitochondria-targeting compound exerts therapeutic effects against melanoma by inducing mitochondria-mediated apoptosis and autophagy in vitro and in vivo

Melanoma is the most invasive skin cancer, with a high mortality rate. However, existing therapeutic drugs have side effects, low reactivity, and lead to drug resistance. As the power source in cells, mitochondria play an important role in the survival of cancer cells and are an important target for tumor therapy. This study aimed to develop a new anti-melanoma compound that targets mitochondria, evaluate its effect on the proliferation and metastasis of melanoma cells, and explore its mechanism of action. The novel mitochondria-targeting compound, SCZ0148, was synthesized by modifying the structure of cyanine. Then, A375 and B16 cells were incubated with different concentrations of SCZ0148, and different doses of SCZ0148 were administered to A375 and B16 xenograft zebrafish. The results showed that SCZ0148 targeted mitochondria, had dose- and time-dependent effects on the proliferation of melanoma cell lines, and had no obvious side effects on normal cells. In addition, SCZ0148 induced melanoma cell apoptosis through the reactive oxygen species-mediated mitochondrial pathway of apoptosis and promoted autophagy. SCZ0148 significantly inhibited the migration of melanoma cells via a matrix metalloprotein 9-mediated pathway. Similarly, SCZ0148 inhibited melanoma cell proliferation in a concentration-dependent manner in vivo. In summary, SCZ0148 may be a novel anti-melanoma compound that targets mitochondria.

Advances in the interaction between endoplasmic reticulum stress and osteoporosis

The endoplasmic reticulum (ER) is the main site for protein synthesis, folding, and secretion, and accumulation of the unfolded/misfolded proteins in the ER may induce ER stress. ER stress is an important participant in various intracellular signaling pathways. Prolonged- or high-intensity ER stress may induce cell apoptosis. Osteoporosis, characterized by imbalanced bone remodeling, is a global disease caused by many factors, such as ER stress. ER stress stimulates osteoblast apoptosis, increases bone loss, and promotes osteoporosis development. Many factors, such as the drug's adverse effects, metabolic disorders, calcium ion imbalance, bad habits, and aging, have been reported to activate ER stress, resulting in the pathological development of osteoporosis. Increasing evidence shows that ER stress regulates osteogenic differentiation, osteoblast activity, and osteoclast formation and function. Various therapeutic agents have been developed to counteract ER stress and thereby suppress osteoporosis development. Thus, inhibition of ER stress has become a potential target for the therapeutic management of osteoporosis. However, the in-depth understanding of ER stress in the pathogenesis of osteoporosis still needs more effort.

Effects of Long-Term Exposure to Copper on Mitochondria-Mediated Apoptosis in Pig Liver

Copper (Cu) is listed as one of the main heavy metal pollutants, which poses potential health risks to humans. Excessive intake of Cu has shown toxic effects on the organs of many animals, and the liver is one of the most important organs to metabolize it. In this study, pigs, the mammal with similar metabolic characteristics to humans, were selected to assess the effects of long-term exposure to Cu on mitochondria-mediated apoptosis, which are of great significance for studying the toxicity of Cu to humans. Pigs were fed a diet with different contents of Cu (10, 125, and 250 mg/kg) for 80 days. Samples of blood and liver tissue were collected on days 40 and 80. Experimental results demonstrated that the accumulation of Cu in the liver was increased in a dose-dependent and time-dependent manner. Meanwhile, the curve of pig's body weight showed that a 125 mg/kg Cu diet promoted the growth of pigs during the first 40 days and then inhibited it from 40 to 80 days, while the 250 mg/kg Cu diet inhibited the growth of pigs during 80 days of feeding. Additionally, the genes and protein expression levels of Caspase-3, p53, Bax, Bak1, Bid, Bad, CytC, and Drp1 in the treatment group were higher than that in the control group, while Bcl-2, Bcl-xL, Opa1, Mfn1, and Mfn2 were decreased. In conclusion, these results indicated that long-term excessive intake of Cu could inhibit the growth of pigs and induced mitochondria-mediated apoptosis by breaking the mitochondrial dynamic balance. Synopsis: Long-term exposure to high doses of Cu could lead to mitochondrial dysfunction by breaking the mitochondrial dynamic balance, which ultimately induced mitochondria-mediated apoptosis in the liver of pigs. This might be closely related to the growth inhibition and liver damage in pigs.

Advent of phytobiologics and nano-interventions for bone remodeling: a comprehensive review

Bone metabolism constitutes the intricate processes of matrix deposition, mineralization, and resorption. Any imbalance in these processes leads to traumatic bone injuries and serious disease conditions. Therefore, bone remodeling plays a crucial role during the regeneration process maintaining the balance between osteoblastogenesis and osteoclastogenesis. Currently, numerous phytobiologics are emerging as the new therapeutics for the treatment of bone-related complications overcoming the synthetic drug-based side effects. They can either target osteoblasts, osteoclasts, or both through different mechanistic pathways for maintaining the bone remodeling process. Although phytobiologics have been widely used since tradition for the treatment of bone fractures recently, the research is accentuated toward the development of osteogenic phytobioactives, constituent-based drug designing models, and efficacious delivery of the phytobioactives. To achieve this, different plant extracts and successful isolation of their phytoconstituents are critical for osteogenic research. Hence, this review emphasizes the phytobioactives based research specifically enlisting the plants and their constituents used so far as bone therapeutics, their respective isolation procedures, and nanotechnological interventions in bone research. Also, the review enlists the vast array of folklore plants and the newly emerging nano-delivery systems in treating bone injuries as the future scope of research in the phytomedicinal orthopedic applications.

Maintenance of increased bone mass after PTH withdrawal by sequential medicarpin treatment via augmentation of cAMP-PKA pathway

Osteoporosis is a metabolic bone disorder associated with impaired bone microarchitecture leading to fragility fractures. Long-term usage of parathyroid hormone (PTH) enhances bone resorption and leads to osteosarcoma in rats which limits its exposure to maximum 2 years in human. Notably, the anabolic effects of PTH do not endure in the absence of sustained administration. Studies in our lab identified osteogenic and antiresorptive activity in medicarpin, a phytoestrogen belonging to the pterocarpan class. Considering dual-acting property of medicarpin and limitations of PTH therapy, we envisaged that medicarpin sequential treatment after PTH withdrawal could serve as promising therapeutic approach for osteoporosis treatment. As PTH exerts its bone anabolic effect by increasing osteoblast survival, our study aims to determine whether medicarpin amplifies this effect of PTH. Our results show that PTH withdrawal led to reduced bone mineral density and bone parameters, while sequential treatment of medicarpin after PTH withdrawal significantly enhanced these parameters. Remarkably, these effects were more pronounced than 8-week PTH treatment. Sequential therapy also significantly increased P1NP levels and decreased CTX levels and TRAP positive cells compared to PTH 8W group where CTX levels were quite high due to bone resorptive action of PTH. Protein expression studies revealed that medicarpin along with PTH betters the antiapoptotic potential compared to PTH alone, through augmentation of cyclic adenosine monophosphate-PKA-CREB pathway. These results proclaim that medicarpin sequential treatment prevented the reduction in bone accrual and strength accompanying PTH withdrawal and also aided in antiapoptotic role of PTH. The study points toward the potential use of medicarpin as a replacement therapeutic option postdiscontinuation of PTH.

Characterization of chikusetsusaponin IV and V induced apoptosis in HepG2 cancer cells

BACKGROUND

Chikusetsusaponin IV and V (CsIV and CsV), two typical oleanolic acid saponins, are mainly derived from the rhizome of Panax japonicus C.A. Mey. To reveal the anti-cancer effect of CsIV and CsV on liver cancer cells, human hepatic cancer cell lines (HepG2) were exposed to these saponins, and various physiological responses of HepG2 were investigated.

METHODS AND RESULTS

HepG2 cells were treated with CsIV, CsV and 5-fluorouracil (5-FU). Cell proliferation was measured by CCK-8 assay. The cell cycle arrest, cell apoptosis and intracellular Ca²⁺ levels were respectively identified by flow cytometry. The mitochondrial membrane potential was detected by fluorescence microscopy. And, the levels of apoptosis-related proteins were analyzed by western blotting. Both CsIV and CsV were demonstrated to inhibit cell viability, and induce cell cycle arrest and apoptosis of HepG2 in a dose-dependent manner. They also enhanced the intracellular Ca²⁺ level and decreased the mitochondrial membrane potential in HepG2 cells. Furthermore, p53 and p21 were found up-regulated in HepG2 cells treated by CsIV and CsV. The apoptotic proteins, bax, cytochrome c, cleaved caspase-3/-9, were all found activated in HepG2 cells after CsIV and CsV treatment. The anti-apoptotic protein, bcl-2, was significantly down-regulated in all treated HepG2 cells.

CONCLUSION

Our data demonstrated that CsIV and CsV exerted significant cytotoxic effects on HepG2 cells without affecting normal liver cells. And, these chikusetsusaponins, especially for CsIV, showed a potent effect on promoting cell apoptosis in HepG2 cells, which was associated with the activation of p53-mediated apoptosis pathway.

Systems pharmacology approach uncovers the therapeutic mechanism of medicarpin against scopolamine-induced memory loss

BACKGROUND

Medicarpin is a natural pterocarpan-type phytoalexin widely distributed in many traditional Chinese medicines, such as Astragali Radix. A previous study showed that Astragali Radix demonstrated promising protective effects in neurons. However, there is no reported study on the neuroprotective function and the underlying mechanism of Medicarpin.

PURPOSE

This study aimed to demonstrate the neuroprotective effect of Medicarpin on Alzheimer's disease (AD) and explore the therapeutic mechanisms.

METHOD

First, we carried out animal behavioral tests and biochemical analysis to assess the anti-AD potential of Medicarpin for ameliorating spatial learning and memory and modulating cholinergic metabolism in scopolamine-induced amnesic mice. Subsequently, network proximity prediction was used to measure the network distance between the Medicarpin target network and AD-related endophenotype module. We identified Medicarpin-regulated AD pathological processes and highlighted the key disease targets via network analysis. Finally, experimental approaches including Nissl staining and Western blotting were conducted to validate our network-based findings.

RESULT

In this study, we first observed that Medicarpin can ameliorate cognitive and memory dysfunction and significantly modulate cholinergic metabolism in scopolamine-induced amnesic mice. We then proposed an endophenotype network-based framework to comprehensively explore the AD therapeutic mechanisms of Medicarpin by integrating 25 AD-related endophenotype modules, gold-standard AD seed genes, an experimentally validated drug-target network of Medicarpin, and a global human protein-protein interactome. In silico prediction revealed that the effect of Medicarpin is highly relevant to neuronal apoptosis and synaptic plasticity, which was validated by experimental assays. Network analysis and Western blotting further identified two key targets, GSK-3β and MAPK14 (p38), in the AD-related protein regulatory network, which play key roles in the regulation of neuronal apoptosis and synaptic plasticity by Medicarpin.

CONCLUSIONS

This study presented a powerful endophenotype network-based strategy to explore the mechanisms of action (MOAs) of new AD therapeutics, and first identified Medicarpin as a potential anti-AD candidate by targeting multiple pathways.

Lessons from Exploring Chemical Space and Chemical Diversity of Propolis Components

Propolis is a natural resinous material produced by bees and has been used in folk medicines since ancient times. Due to it possessing a broad spectrum of biological activities, it has gained significant scientific and commercial interest over the last two decades. As a result of searching 122 publications reported up to the end of 2019, we assembled a unique compound database consisting of 578 components isolated from both honey bee propolis and stingless bee propolis, and analyzed the chemical space and chemical diversity of these compounds. The results demonstrated that both honey bee propolis and stingless bee propolis are valuable sources for pharmaceutical and nutraceutical development.

Dose- and Time-Dependent Cytotoxicity of Carteolol in Corneal Endothelial Cells and the Underlying Mechanisms

Carteolol is a non-selective β-adrenoceptor antagonist used for the treatment of glaucoma, and its abuse might be cytotoxic to the cornea. However, its cytotoxicity and underlying mechanisms need to be elucidated. Herein, we used an in vivo model of feline corneas and an in vitro model of human corneal endothelial cells (HCECs), respectively. In vivo results displayed that 2% carteolol (clinical dosage) could induce monolayer density decline and breaking away of feline corneal endothelial (FCE) cells. An in vitro model of HCECs that were treated dose-dependently (0.015625–2%) with carteolol for 2–28 h, resulted in morphological abnormalities, declining in cell viability and elevating plasma membrane (PM) permeability in a dose- and time- dependent manner. High-dose (0.5–2%) carteolol treatment induced necrotic characteristics with uneven distribution of chromatin, marginalization and dispersed DNA degradation, inactivated caspase-2/-8, and increased RIPK1, RIPK3, MLKL, and pMLKL expression. The results suggested that high-dose carteolol could induce necroptosis via the RIPK/MLKL pathway. While low-dose (0.015625–0.25%) carteolol induced apoptotic characteristics with chromatin condensation, typical intranucleosomal DNA laddering patterns, G₁ cell-cycle arrest, phosphatidylserine (PS) externalization, and apoptotic body formation in HCECs. Meanwhile, 0.25% carteolol treatment resulted in activated caspase-2, -3, -8, and -9, downregulation of Bcl-2 and Bcl-xL, upregulation of Bax and Bad, ΔΨm disruption, and release of cytoplasmic cytochrome c (Cyt.c) and AIF into the cytoplasm. These observations suggested that low-dose carteolol could induce apoptosis via a caspase activated and mitochondrial-dependent pathway. These results suggested that carteolol should be used carefully, as low as 0.015625% cartelol caused apoptotic cell death in HCECs in vitro.

Bioavailability, tissue distribution and excretion studies of a potential anti-osteoporotic agent, medicarpin, in female rats using validated LC-MS/MS method

Medicarpin, one of the active constituents isolated from the extract of Butea monosperma, has been shown to have various pharmacological activities including potent anti-osteoporotic properties. The aim of this study was to investigate the oral pharmacokinetics, tissue distribution and excretion of medicarpin following single oral dose administration in female rats. Oral pharmacokinetics was explored at 5 and 20 mg/kg while tissue distribution, urinary and fecal excretion were studied following 20 mg/kg oral dose. Medicarpin was quantified in rat plasma, urine, feces and tissue samples using a validated LC-MS/MS method following reverse-phase HPLC separation on RP18 column (4.6 mm × 50 mm, 5.0 μm) using methanol and 10 mM ammonium acetate (pH 4.0) as mobile phase in the ratio of 80:20 (v/v) at a flow rate of 0.8 mL/min. The oral bioavailability of medicarpin was found to be low with low systemic levels. The concentration in tissues was significantly higher than plasma. Highest tissue concentrations were found in the liver followed by bone marrow. Urinary and fecal excretion of medicarpin was < 1 %. In conclusion, medicarpin was found to be highly distributed in body tissues and minimally excreted via urine or feces.

Pharmacological effectors of GRP78 chaperone in cancers

The protein chaperone GRP78 is a master regulator of endoplasmic reticulum (ER) functions and is frequently over-expressed at the surface of cancer cells where it contributes to chemo-resistance. It represents a well-studied ER stress marker but an under-explored target for new drug development. This review aims to untangle the structural and functional diversity of GRP78 modulators, covering over 130 natural products, synthetic molecules, specific peptides and monoclonal antibodies that target GRP78. Several approaches to promote or to incapacitate GRP78 are presented, including the use of oligonucleotides and specific cell-delivery peptides often conjugated to cytotoxic payloads to design GRP78-targeted therapeutics. A repertoire of drugs that turn on/off GRP78 is exposed, including molecules which bind directly to GRP78, principally to its ATP site. There exist many options to regulate positively or negatively the expression of the chaperone, or to interfere with its cellular trafficking. This review provides a molecular cartography of GRP78 pharmacological effectors and adds weight to the notion that GRP78 repressors could represent promising anticancer therapeutics, notably as regards limiting chemo-resistance of cancer cells. The potential of GRP78-targeting drugs in other therapeutic modalities is also evoked.

miR‑495 enhances the efficacy of radiotherapy by targeting GRP78 to regulate EMT in nasopharyngeal carcinoma cells

Glucose-regulated protein 78 (GRP78) was revealed to be associated with the radioresistance of nasopharyngeal carcinoma (NPC) in our previous study. GRP78 is a highly expressed cell surface protein, and holds great promise as a cancer specific target. Its expression may be impacted by the regulation of miRNAs, which may be involved in the radioresistance of NPC. A better understanding of the mechanisms of radioresistance may generate new targets of therapy for NPC patients. The present study was designed to investigate the effect of microRNA targeting GRP78 on the radiosensitivity of NPC. First, we used miRWalk software to predict miRNAs that may interact with GRP78. Subsequently, analysis of miR-495 and GRP78 expression was performed in the primary tissues of 92 NPC tissues and cell lines by immunohistochemistry and real-time PCR and the results revealed that miR-495 expression was lower in radioresistant NPC tissues in comparison to chronic rhinitis tissues, and also lower in radioresistant 5-8F cells (5-8F-IR) in comparison to its parental 5-8F cells. Notably, we observed an inverse association between the expression miR-495 and GRP78. Our bioinformatics analysis led to the identification of miR-495 as the optimal miRNA interacting with GRP78 mRNA. Furthermore, miR-495 targeting the 3′untranslated region (UTR) of GRP78 was detected by a Dual-Glo Luciferase Assay system. Finally, we observed that miR-495 inhibition led to a significant increase in the radioresistance of 5-8F cells and higher GRP78 expression, which may be involved in epithelial-mesenchymal transition (EMT) phenotype. miR-495 targeted the 3′UTR of GRP78 and contributed to the efficacy of radiation therapy in NPC.

Total Synthesis of (+)-Medicarpin

(+)-Medicarpin has been synthesized asymmetrically for the first time in a linear scalable process with an overall yield of 11%. The two chiral centers were constructed in one step via condensation using a chiral oxazolidinone auxiliary. This method will likely accelerate research on medicarpin as an erythropoietin inducer for erythropoietin-deficient diseases.

Lariciresinol induces apoptosis in HepG2 cells via mitochondrial-mediated apoptosis pathway

Lariciresinol (LA) is one of the main active ingredients in many traditional medicinal plants such as Patrinia, and has the role of anti-liver cancer. However, the precise mechanisms are unclear. This study investigated the molecular mechanisms of LA against HepG2 cells. LA anti-tumor activity was assessed with the CCK-8, Ki-67, and immunofluorescence staining. Cells apoptotic ratio was evaluated by Annexin V/PI double-staining assay. A proteomic approach was used to identify differentially expressed proteins after LA treatment. JC-1 staining was carried out to detect the mitochondrial membrane potential (ΔΨm), and the Western blot analysis was used to analyse the apoptosis-associated proteins. Our results suggested that LA significantly suppressed the viability of HepG2 cells. The CCK-8 and Ki-67 expression indicated dose-dependent decreases in cell proliferation. Flow cytometry analysis showed that LA exhibited a apoptosis-inducing effect. The proteomic study observed the presence of apoptosis-associated proteins and mitochondrial dysfunction in HepG2 cells after LA-treatment. Further analysis showed that LA could trigger the mitochondrial-mediated apoptosis pathway, based on a decrease in ΔΨm; deliver of cytochrome c; activation of caspase-9/-3 and poly(ADP-ribose) polymerase; and decrease of the proportion of Bcl-2/Bax. Collectively, our studies found that LA exhibits significant cytotoxic effects by inhibiting cell proliferation, inducing apoptosis, possibly via activation of the mitochondrial-mediated apoptosis pathway.

Upregulation of Glucose-Regulated Protein 78 in Metastatic Cancer Cells Is Necessary for Lung Metastasis Progression

Metastasis is the cause of more than 90% of all cancer deaths. Despite this fact, most anticancer therapeutics currently in clinical use have limited efficacy in treating established metastases. Here, we identify the endoplasmic reticulum chaperone protein, glucose-regulated protein 78 (GRP78), as a metastatic dependency in several highly metastatic cancer cell models. We find that GRP78 is consistently upregulated when highly metastatic cancer cells colonize the lung microenvironment and that mitigation of GRP78 upregulation via short hairpin RNA or treatment with the small molecule IT-139, which is currently under clinical investigation for the treatment of primary tumors, inhibits metastatic growth in the lung microenvironment. Inhibition of GRP78 upregulation and an associated reduction in metastatic potential have been shown in four highly metastatic cell line models: three human osteosarcomas and one murine mammary adenocarcinoma. Lastly, we show that downmodulation of GRP78 in highly metastatic cancer cells significantly increases median survival times in our in vivo animal model of experimental metastasis. Collectively, our data indicate that GRP78 is an attractive target for the development of antimetastatic therapies.