Ursolic Acid Accelerates Paclitaxel-Induced Cell Death in Esophageal Cancer Cells by Suppressing Akt/FOXM1 Signaling Cascade

Role of ursolic acid in preventing gastrointestinal cancer: recent trends and future perspectives

Gastrointestinal malignancies are one of the major worldwide health concerns. In the present review, we have assessed the plausible therapeutic implication of Ursolic Acid (UA) against gastrointestinal cancer. By modulating several signaling pathways critical in cancer development, UA could offer anti-inflammatory, anti-proliferative, and anti-metastatic properties. However, being of low oral bioavailability and poor permeability, its clinical value is restricted. To deliver and protect the drug, liposomes and polymer micelles are two UA nanoformulations that can effectively increase medicine stability. The use of UA for treating cancers is safe and appropriate with low toxicity characteristics and a predictable pharmacokinetic profile. Although the bioavailability of UA is limited, its nanoformulations could emerge as an alternative to enhance its efficacy in treating GI cancers. Further optimization and validation in the clinical trials are necessary. The combination of molecular profiling with nanoparticle-based drug delivery technologies holds the potential for bringing UA to maximum efficacy, looking for good prospects with GI cancer treatment.

Colloidal and Biological Characterization of Dual Drug-Loaded Smart Micellar Systems

Smart polymeric micelles (PMs) are of great interest in drug delivery owing to their low critical micellar concentration and sizes. In the present study, two different pH-sensitive poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) copolymer samples were used for the encapsulation of paclitaxel (PTX), ursolic acid (UA), and dual loading of PTX and UA. Based on the molecular features of copolymers, spherical PMs with sizes of around 35 nm and 140 nm were obtained by dialysis for P2VP55-b-PEO284 and P2VP274-b-PEO1406 samples, respectively. The micellar sizes increased after loading of both drugs. Moreover, drug encapsulation and loading efficiencies varied from 53 to 94% and from 3.2 to 18.7% as a function of the copolymer/drug ratio, molar mass of copolymer sample, and drug type. By FT-IR spectroscopy, it was possible to demonstrate the drug loading and the presence of some interactions between the polymer matrix and loaded drugs. In vitro viability was studied on 4T1 mammary carcinoma mouse cells as a function of time and concentration of drug-loaded PMs. UA-PMs and free PMs alone were not effective in inhibiting the tumor cell growth whereas a viability of 40% was determined for cells treated with both PTX- and PTX/UA-loaded PMs. A synergic effect was noticed for PTX/UA-loaded PMs.

Dual-drug controllable co-assembly nanosystem for targeted and synergistic treatment of hepatocellular carcinoma

The effectiveness of chemotherapeutic agents for hepatocellular carcinoma (HCC) is unsatisfactory because of tumor heterogeneity, multidrug resistance, and poor target accumulation. Therefore, multimodality-treatment with accurate drug delivery has become increasingly popular. Herein, a cell penetrating peptide-aptamer dual modified-nanocomposite (USILA NPs) was successfully constructed by coating a cell penetrating peptide and aptamer onto the surface of sorafenib (Sora), ursolic acid (UA) and indocyanine green (ICG) condensed nanodrug (USI NPs) via one-pot assembly for targeted and synergistic HCC treatment. USILA NPs showed higher cellular uptake and cytotoxicity in HepG2 and H22 cells, with a high expression of epithelial cell adhesion molecule (EpCAM). Furthermore, these NPs caused more significant mitochondrial membrane potential reduction and cell apoptosis. These NPs could selectively accumulate at the tumor site of H22 tumor-bearing mice and were detected with the help of ICG fluorescence; moreover, they retarded tumor growth better than monotherapy. Thus, USILA NPs can realize the targeted delivery of dual drugs and the integration of diagnosis and treatment. Moreover, the effects were more significant after co-administration of iRGD peptide, a tumor-penetrating peptide with better penetration promoting ability or programmed cell death ligand 1 (PD-L1) antibody for the reversal of the immunosuppressive state in the tumor microenvironment. The tumor inhibition rates of USILA NPs + iRGD peptide or USILA NPs + PD-L1 antibody with good therapeutic safety were 72.38 % and 67.91 % compared with control, respectively. Overall, this composite nanosystem could act as a promising targeted tool and provide an effective intervention strategy for enhanced HCC synergistic treatment.

Synergistic anti-tumor effect of dual drug co-assembled nanoparticles based on ursolic acid and sorafenib

Both ursolic acid (UA) and sorafenib (Sora) have been generally utilized in cancer treatment, and the combination of the two has also shown a good anti-tumor effect. However, single-agent therapy for Hepatocellular carcinoma (HCC) has the disadvantages of multi-drug resistance, poor water solubility and low bioavailability, and the application of traditional nanocarrier materials is limited due to their low drug loading and low carrier-related toxicity. Therefore, we prepared US NPs with different proportions of UA and Sora by solvent exchange method for achieving synergistic HCC therapy. US NPs had suitable particle size, good dispersibility and storage stability, which synergistically inhibited the proliferation of HepG2 cells, SMMC7721 cells and H22 cells. In addition, we also proved that US NPs were able to suppress the migration of HepG2 cells and SMMC7721 cells and reduce the adhesion ability and colony formation ability of these cells. According to the results, US NPs could degrade the membrane potential of mitochondrial, participate in cell apoptosis, and synergistically induce autophagy. Collectively, the carrier-free US NPs provide new strategies for HCC treatment and new ideas for the development of novel nano-drug delivery systems containing UA and Sora.

miRNAs as short non-coding RNAs in regulating doxorubicin resistance

The treatment of cancer patients has been prohibited by chemoresistance. Doxorubicin (DOX) is an anti-tumor compound disrupting proliferation and triggering cell cycle arrest via inhibiting activity of topoisomerase I and II. miRNAs are endogenous RNAs localized in cytoplasm to reduce gene level. Abnormal expression of miRNAs changes DOX cytotoxicity. Overexpression of tumor-promoting miRNAs induces DOX resistance, while tumor-suppressor miRNAs inhibit DOX resistance. The miRNA-mediated regulation of cell death and hallmarks of cancer can affect response to DOX chemotherapy in tumor cells. The transporters such as P-glycoprotein are regulated by miRNAs in DOX chemotherapy. Upstream mediators including lncRNAs and circRNAs target miRNAs in affecting capacity of DOX. The response to DOX chemotherapy can be facilitated after administration of agents that are mostly phytochemicals including curcumol, honokiol and ursolic acid. These agents can regulate miRNA expression increasing DOX's cytotoxicity. Since delivery of DOX alone or in combination with other drugs and genes can cause synergistic impact, the nanoparticles have been introduced for drug sensitivity. The non-coding RNAs determine the response of tumor cells to doxorubicin chemotherapy. microRNAs play a key role in this case and they can be sponged by lncRNAs and circRNAs, showing interaction among non-coding RNAs in the regulation of doxorubicin sensitivity.

Small-molecule inhibitors targeting FOXM1: Current challenges and future perspectives in cancer treatments

Forkhead box (FOX) protein M1 (FOXM1) is a critical proliferation-associated transcription factor (TF) that is aberrantly overexpressed in the majority of human cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in, cell proliferation, cell migration, invasion, angiogenesis and metastasis. The FOXM1 as a TF directly or indirectly regulates the expression of several target genes whose dysregulation is associated with almost all hallmarks of cancer. Moreover, FOXM1 expression is associated with chemoresistance to different anti-cancer drugs. Several studies have confirmed that suppression of FOXM1 enhanced the drug sensitivity of various types of cancer cells. Current data suggest that small molecule inhibitors targeting FOXM1 in combination with anticancer drugs may represent a novel therapeutic strategy for chemo-resistant cancers. In this review, we discuss the clinical utility of FOXM1, further, we summarize and discuss small-molecule inhibitors targeting FOXM1 and categorize them according to their mechanisms of targeting FOXM1. Despite great progress, small-molecule inhibitors targeting FOXM1 face many challenges, and we present here all small-molecule FOXM1 inhibitors in different stages of development. We discuss the current challenges and provide insights on the future application of FOXM1 inhibition to the clinic.

Inhibition of the interaction between Hippo/YAP and Akt signaling with ursolic acid and 3'3-diindolylmethane suppresses esophageal cancer tumorigenesis

Hippo/YAP signaling hinders cancer progression. Inactivation of this pathway contributes to the development of esophageal cancer by activation of Akt. However, the possible interaction between Akt and Hippo/YAP pathways in esophageal cancer progression is unclear. In this study, we found that ursolic acid (UA) plus 3'3-diindolylmethane (DIM) efficiently suppressed the oncogenic Akt/Gsk-3β signaling pathway while activating the Hippo tumor suppressor pathway in esophageal cancer cells. Moreover, the addition of the Akt inhibitor LY294002 and the PI3K inhibitor 3-methyladenine enhanced the inhibitory effects of UA plus DIM on Akt pathway activation and further stimulated the Hippo pathway, including the suppression of YAP nuclear translocation in esophageal cancer cells. Silencing YAP under UA plus DIM conditions significantly increased the activation of the tumor suppressor PTEN in esophageal cancer cells, while decreasing p-Akt activation, indicating that the Akt signaling pathway could be down-regulated in esophageal cancer cells by targeting PTEN. Furthermore, in a xenograft nude mice model, UA plus DIM treatment effectively diminished esophageal tumors by inactivating the Akt pathway and stimulating the Hippo signaling pathway. Thus, our study highlights a feedback loop between the PI3K/Akt and Hippo signaling pathways in esophageal cancer cells, implying that a low dose of UA plus DIM could serve as a promising chemotherapeutic combination strategy in the treatment of esophageal cancer.

Ursolic Acid Ameliorated Neuronal Damage by Restoring Microglia-Activated MMP/TIMP Imbalance in vitro

Purpose

The oxygen and glucose deprivation-reoxygenation (OGDR) model is widely used to evaluate ischemic stroke and cerebral ischemia-reperfusion (I/R) injury in vitro. Excessively activated microglia produce pro-inflammatory mediators such as matrix metalloproteinases [MMPs] and their specific inhibitors, tissue inhibitors of metalloproteinases [TIMPs], causing neuronal damage. Ursolic acid (UA) acts as a neuroprotective agent in the rat middle cerebral artery occlusion/reperfusion (MCAO/R) model keeping the MMP/TIMP balance with underlying mechanisms unclear. Our study used OGDR model to determine whether and how UA reduces neuronal damage by reversing MMP/TIMP imbalance caused by microglia in I/R injury in vitro.

Methods

SH-SY5Y cells were first cultured with 95% N2 and 5% CO2 and then cultivated regularly for OGDR model. Cell viability was tested for a proper UA dose. We established a co-culture system with SH-SY5Y cells and microglia-conditioned medium (MCM) stimulated by lipopolysaccharide (LPS) and interferon-gamma (IFNγ). MMP9 and TIMP1 levels were measured with ELISA assay to confirm the UA effect. We added recombinant MMP9 (rMMP9) and TIMP1 neutralizing antibody (anti-TIMP1) for reconfirmation. Transmission electron microscopy was used to observe cell morphology, and flow cytometry and Annexin V-FITC and PI labeling for apoptotic conditions. We further measured the calcium fluorescence intensity in SH-SY5Y cells.

Results

The MCM significantly reduced cell viability of SH-SY5Y cells after OGDR (p<0.01), which was restored by UA (0.25 µM) (p<0.05), whereas lactate dehydrogenase activity, intraneuronal Ca2+ concentration, and apoptosis-related indexes were showed significant improvement after UA treatment (p<0.01). UA corrected the MMP/TIMP imbalance by decreasing MMP9 expression and increasing TIMP1 expression in the co-culture system (p<0.01) and the effects of UA on SH-SY5Y cells were mitigated by the administration of rMMP9 and anti-TIMP1 (p<0.01).

Conclusion

We demonstrated that UA inhibited microglia-induced neuronal cell death in an OGDR model of ischemic reperfusion injury by stabilizing the MMP9/TIMP1 imbalance.

Targeting prolyl isomerase Pin1 as a promising strategy to overcome resistance to cancer therapies

The development of tumor therapeutic resistance is one of the important reasons for the failure of antitumor therapy. Starting with multiple targets and multiple signaling pathways is helpful in understanding the mechanism of tumor resistance. The overexpression of prolyl isomerase Pin1 is highly correlated with the malignancy of cancer, since Pin1 controls many oncogenes and tumor suppressors, as well as a variety of cancer-driving signaling pathways. Strikingly, numerous studies have shown that Pin1 is directly involved in therapeutic resistance. In this review, we mainly summarize the functions and mechanisms of Pin1 in therapeutic resistance of multifarious cancers, such as breast, liver, and pancreatic carcinomas. Furtherly, from the perspective of Pin1-driven cancer signaling pathways including Raf/MEK/ERK, PI3K/Akt, Wnt/β-catenin, NF-κB, as well as Pin1 inhibitors containing juglone, epigallocatechin-3-gallate (EGCG), all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), it is better to demonstrate the important potential role and mechanism of Pin1 in resistance and sensitization to cancer therapies. It will provide new therapeutic approaches for clinical reversal and prevention of tumor resistance by employing synergistic administration of Pin1 inhibitors and chemotherapeutics, implementing combination therapy of Pin1-related cancer signaling pathway inhibitors and Pin1 inhibitors, and exploiting novel Pin1-specific inhibitors.