Comparison of cantharidin toxicity in breast cancer cells to two common chemotherapeutics

Ursolic Acid Decreases the Proliferation of MCF-7 Cell-Derived Breast Cancer Stem-Like Cells by Modulating the ERK and PI3K/AKT Signaling Pathways

Cancer stem cells are strong drivers of metastasis and cancer relapse, which makes them important therapeutic targets. Ursolic acid (UA), a pentacyclic triterpenoid, has anticancer effects in various types of cancer; however, little is known about its effect on the growth of MCF-7 cell-derived breast cancer stem (BCS)-like cells in estrogen receptor positive breast cancer. In this study, the anticancer activity of UA in MCF-7 cell-derived BCS-like cells and its mechanism of action were evaluated. Furthermore, its inhibitory effects on the proliferation of MCF-7 cell-derived BCS-like cells were compared with that on MCF-7 cells. In MCF-7 cells, UA increased p53 and p21 expression but decreased cyclin D, cyclin E, CDK4, and CDK2 expression to induce cell cycle arrest in the G0/G1 phase. Moreover, UA significantly suppressed migration, invasion, and colony formation in MCF-7 cells, and suppressed mammosphere formation in a concentration- dependent manner. In MCF-7 cell-derived BCS-like cells, UA significantly decreased migration, suppressed p-PI3K, p-AKT, and p-ERK expression, and enhanced p-FoxO1/FoxO3a expression. Accordingly, in MCF-7 cell-derived BCS-like cells, UA suppressed proliferation in part by downregulating ERK and PI3K/AKT signaling pathways. These findings provide the first evidence for the selective effects of UA in BCSs.

Dioscin Decreases Breast Cancer Stem-like Cell Proliferation via Cell Cycle Arrest by Modulating p38 Mitogen-activated Protein Kinase and AKT/mTOR Signaling Pathways

Dioscin (DS), a steroidal saponin, has been shown to have anti-cancer activity by exerting antioxidant effects and inducing apoptosis. However, the anti-cancer activity of DS in breast cancer-derived stem cells is still controversial. The purpose of this study was to evaluate the effects of DS on migration, invasion, and colony formation in MDA-MB-231 and MCF-7 cell lines and the mechanism by which it inhibits proliferation of breast cancer stem-like cells after inducing differentiation into breast cancer stem cells. DS treatment significantly reduced cellular migration, invasion, and colony formation in MDA-MB-231 and MCF-7 cells. During the differentiation process that induced manifestation of breast cancer stem-like cells, DS significantly inhibited mammosphere formation in a dose-dependent manner and increased the expression of p53 and p21 in breast cancer stem-like cells, reducing the expression of cdc2 and cyclin B1 in MDA-MB-231 cells and cyclin D, cyclin E, CDK4, and CDK2 in MCF-7 cells. Interestingly, DS treatment induced G2/M and G0/G1 cell cycle arrest in the MDA-MB-231 and MCF-7 cells, respectively. DS also increased the phosphorylation of p38 and decreased the expression levels of p-AKT and p-mTOR. These results suggest that DS regulates the p38 mitogen-activated protein kinase and AKT/mTOR signaling pathways to reduce the proliferation of breast cancer stem-like cells through cell cycle arrest. Therefore, these findings suggest that DS may serve as a potential treatment candidate targeting breast cancer stem cells.

Double benefit of metformin treatment: improved bladder function in cyclophosphamide-induced cystitis and enhanced cytotoxicity in cancer cells

Cyclophosphamide (CP) is a widely used anti-neoplastic drug; however, it leads to bladder dysfunction in the form of hemorrhagic cystitis that is a serious dose-limiting complication in cancer patients. We aimed to evaluate the protective effects of metformin (MET) in a mouse model of CP-related cystitis in parallel with its effect on CP-induced cytotoxicity in a breast cancer cell line, MDA-MB-231. Cystitis was induced by a single intraperitoneal injection of CP (300 mg/kg), and mice were administered MET, mesna, or vehicle treatment. 24 hours after cystitis induction, the bladders were removed for histopathological analysis and ex vivo evaluation of detrusor muscle contractility. The effect of MET on the cytotoxicity of CP in MDA-MB-231 cells was evaluated as the viability of the cells via MTT assay. Histopathological evaluation confirmed that CP induced a severe cystitis, and MET partially inhibited CP-induced bladder damage. Carbachol-evoked cholinergic contractions were significantly decreased in detrusor strips of mice injected with CP only compared to control (E_max=293.67± 20.00 vs. 497.79± 21.78 mg tension/mg tissue, respectively). In CP-injected mice, treatment with 100 mg/kg MET restored cholinergic contractions (E_max=473.72±62.61 mg tension/mg tissue). In MDA-MB-231 cells, MET decreased their viability, and the combination of MET and CP caused more decrease in cell viability as compared to CP alone (p<0.05), demonstrating that MET enhances the cytotoxicity of CP in these cancer cells. Our results indicate that MET has a strong potential as a therapeutic adjuvant to prevent CP-induced cystitis while enhancing the efficacy of CP.

Evaluation of the treatment strategies on patient-derived xenograft mice of human breast tumor

Since only a minority of patients may respond to single-agent therapies, methods to test the potential antitumor activity of rational combination therapies are still needed. This study aimed to characterize the efficacy of antitumor combination therapies in vivo within the primary tumor using patient-derived xenograft (PDX) models by gamma-irradiation-induced immune suppression. We employed four Luminal A PDX models obtained from human mammary tumors grown in mice. PDX models were implanted into the right flank of mice, and treatments have ensued once tumor volume reached ~150 mm3. Four of the active drugs- Adriamycin, Cyclophosphamide, Taxotere, and Tamoxifen-were tested in vivo to treat mammary tumors. The tumor volume was measured during the study. The mice's immune system was inherently suppressed by gamma irradiation, thus allowing human tumors to grow. The results showed that the tumorigenesis rate of the PDX model was from 65 to 80%. PDX models were successfully established with a high frequency of tumor engraftment. Humanized mice treated with a two-drug regimen, that is, adriamycin + cyclophosphamide exhibited an increased antitumor response than a three-drug regimen, that is, adriamycin + cyclophosphamide + taxotere that correlated with tumor growth inhibition. Combination therapies with adriamycin + cyclophosphamide in PDX mice reduced tumor growth in four Luminal A PDX models. These preclinical results suggest that a two-drug regimen than a three-drug regimen can be useful for breast cancer patients. This study provides insights for future studies combining chemotherapeutics with targeted therapies using PDX models by gamma-irradiation-induced immune suppression.

A comparative study on schizophyllan and chitin nanoparticles for ellagic acid delivery in treating breast cancer

In this study, following encapsulation of ellagic acid (EA), an anti-cancer agent, loaded in schizophyllan (EA/SPG-NP) and chitin (EA/Ch-NP) nanoparticles, its release in 95% ethanol, and different mediums of digestive systems with pH ranging 1.5 to 7.4, were examined before investigating for treatment of breast cancer MCF-7cells. Following synthesis, the EA was characterized by FT-IR, SEM, XRD, DLS and zeta potential analysis. Loading capacity of schizophyllan and chitin were 30.08 and 79.52%, respectively, while SEM images indicated respective size distributions of 217.8 and 39.82 nm, with the corresponding zeta potentials being +27 and -9.14 mV. As EA was loaded in nanoparticles, antioxidant activity, examined by DPPH method, of the free EA was found to be higher than both EA/SPG-NP and EA/Ch-NP, but lower than the latter at 7.4 pH. Interestingly, scavenging activities for EA and EA/SPG-NP reduced for higher pH. The MTT cytotoxicity indicated that EA/SPG-NP and EA/Ch-NP inhibited effectively cell growth of breast cancer cell lines at IC₅₀ of 60 and 115 μg/ml, respectively.

Effect of Turkish Propolis on miRNA Expression, Cell Cycle, and Apoptosis in Human Breast Cancer (MCF-7) Cells

Enriched in flavonoid compounds, phenol acids, and terpene derivatives, propolis has been shown to regulate apoptosis signaling pathways and alter the expression of microRNAs (miRNAs). In the present study, it has been aimed to examine the effects of Turkish propolis on miRNA levels of breast cancer (MCF-7) cells, and its relationship with cell proliferation and apoptosis. Cytotoxic activity of ethanolic propolis extract (EEP) was evaluated using MTT assay. Mechanisms involved in the cytotoxic action of Turkish propolis in MCF-7 cells were investigated with regard to apoptosis and cell cycle using flow cytometry and western blot. Mitochondrial membrane potential (MMP) were evaluated by spectrofluorometric method. miRNA levels were detected by qRT-PCR method. EEP exhibited selective toxicity against MCF-7 cells compared to normal fibroblast cells. EEP increased the cell cycle arrest at the G₁ phase. EEP elevated the apoptotic cell death through increasing pro-apoptotic protein levels (p21, Bax, p53, p53-Ser46, and p53-Ser15), decreasing MMP and altering the expression levels of specific tumor suppressors (miR-34, miR-15a, and miR-16-5p) and oncogenic (miR-21) miRNAs. These data support that Turkish propolis may be evaluated as a potential natural agent for new anticancer drugs in future.

Luminescent nanomaterials for droplet tracking in a microfluidic trapping array

The use of high-throughput multiplexed screening platforms has attracted significant interest in the field of on-site disease detection and diagnostics for their capability to simultaneously interrogate single-cell responses across different populations. However, many of the current approaches are limited by the spectral overlap between tracking materials (e.g., organic dyes) and commonly used fluorophores/biochemical stains, thus restraining their applications in multiplexed studies. This work demonstrates that the downconversion emission spectra offered by rare earth (RE)-doped β-hexagonal NaYF₄ nanoparticles (NPs) can be exploited to address this spectral overlap issue. Compared to organic dyes and other tracking materials where the excitation and emission is separated by tens of nanometers, RE elements have a large gap between excitation and emission which results in their spectral independence from the organic dyes. As a proof of concept, two differently doped NaYF₄ NPs (europium: Eu³⁺, and terbium: Tb³⁺) were employed on a fluorescent microscopy-based droplet microfluidic trapping array to test their feasibility as spectrally independent droplet trackers. The luminescence tracking properties of Eu³⁺-doped (red emission) and Tb³⁺-doped (green emission) NPs were successfully characterized by co-encapsulating with genetically modified cancer cell lines expressing green or red fluorescent proteins (GFP and RFP) in addition to a mixed population of live and dead cells stained with ethidium homodimer. Detailed quantification of the luminescent and fluorescent signals was performed to confirm no overlap between each of the NPs and between NPs and cells. Thus, the spectral independence of Eu³⁺-doped and Tb³⁺-doped NPs with each other and with common fluorophores highlights the potential application of this novel technique in multiplexed systems, where many such luminescent NPs (other doped and co-doped NPs) can be used to simultaneously track different input conditions on the same platform. Graphical abstract ᅟ.

Clinical Efficacy and Safety of Aidi Injection Plus Docetaxel-Based Chemotherapy in Advanced Nonsmall Cell Lung Cancer: A Meta-Analysis of 36 Randomized Controlled Trials

Background. Aidi injection is an important adjuvant anticancer drug commonly used in China. Can Aidi injection plus docetaxel-based chemotherapy improve clinical efficacy with good safety in NSCLC? To further reveal its clinical effectiveness, we systematically evaluated all the related studies. Method. We collected all the studies about Aidi injection plus docetaxel-based chemotherapy for NSCLC on Medline, Embase, Web of Science, CNKI, VIP, Wanfang, CBM, CENTRAL, Chi-CTR, and US-clinical trials. We evaluated their methodological bias risk according to the Cochrane evaluation handbook (5.1.0), extracted data following the predesigned data extraction form according to the PICO principle, and synthesized the data using meta-analysis. Results. We included 36 RCTs with 2837 patients, and most studies had unclear bias risk. The merged RR values and their 95% CI of meta-analysis for ORR, DCR, and QOL were as follows: 1.30 (1.19, 1.42), 1.17, (1.12, 1.22), and 1.73 (1.54, 1.95). The merged RR values for neutropenia, thrombocytopenia, anemia, gastrointestinal toxicity, hepatorenal dysfunctions, and alopecia were as follows: 0.70 (0.61, 0.79), 0.63 (0.53, 0.75), 0.60 (0.48, 0.75), 0.76 (0.65, 0.89), 0.56 (0.36, 0.88), and 0.58 (0.36, 0.93). Compared with chemotherapy alone, all differences were statistically significant. Subgroup analysis showed that, with 100 ml, 80-100 ml, and 50 ml, Aidi injection could increase the tumor response and Aidi injection plus DP, DC, and DO could increase the tumor response. Meta-analysis results had good stability. Conclusions. Aidi injection plus docetaxel-based chemotherapy, especially plus DP, DC, and DO, may significantly improve the clinical efficacy and QOL in NSCLC. It may also have low risk of hematotoxicity, gastrointestinal toxicity, and low risk of inducing hepatorenal dysfunctions. Aidi injection may have attenuation and synergistic efficacy to docetaxel chemotherapy. All these need to have new evidence to be proved.

Therapeutic relevance of the protein phosphatase 2A in cancer

Chromosomal Instability (CIN) is regarded as a unifying feature of heterogeneous tumor populations, driving intratumoral heterogeneity. Polo-Like Kinase 1 (PLK1), a serine-threonine kinase that is often overexpressed across multiple tumor types, is one of the key regulators of CIN and is considered as a potential therapeutic target. However, targeting PLK1 has remained a challenge due to the off-target effects caused by the inhibition of other members of the polo-like family. Here we use synthetic dosage lethality (SDL), where the overexpression of PLK1 is lethal only when another, normally non-lethal, mutation or deletion is present. Rather than directly inhibiting PLK1, we found that inhibition of PP2A causes selective lethality to PLK1-overexpressing breast, pancreatic, ovarian, glioblastoma, and prostate cancer cells. As PP2A is widely regarded as a tumor suppressor, we resorted to gene expression datasets from cancer patients to functionally dissect its therapeutic relevance. We identified two major classes of PP2A subunits that negatively correlated with each other. Interestingly, most mitotic regulators, including PLK1, exhibited SDL interactions with only one class of PP2A subunits (PPP2R1A, PPP2R2D, PPP2R3B, PPP2R5B and PPP2R5D). Validation studies and other functional cell-based assays showed that inhibition of PPP2R5D affects both levels of phospho-Rb as well as sister chromatid cohesion in PLK1-overexpressing cells. Finally, analysis of clinical data revealed that patients with high expression of mitotic regulators and low expression of Class I subunits of PP2A improved survival. Overall, these observations point to a context-dependent role of PP2A that warrants further exploration for therapeutic benefits.