Isolating Cancer Stem Cells from Solid Tumors.

Over the past 20 years, there has been a lot of interest in the study and investigation of cancer stem cells (CSCs) or tumor-initiating cells (TICs). CSCs are rare, dormant cells and able to self-renew and maintain tumor development and heterogeneity. A new age of basic and clinical cancer research, reclassification of human tumors, and the development of novel therapeutic approaches will undoubtedly result from a better knowledge of CSCs. In order to develop effective and therapeutic strategies to treat cancer, it is crucial to understand the basic characteristics of CSCs, their importance to cancer therapy, and methodologies to isolate, detect, and characterize them. Here, we outline the main methods and protocols to identify, isolate, and culture CSCs from primary tumors.

ALDH Activity Assay: A Method for Cancer Stem Cell (CSC) Identification and Isolation.

Cancer stem cells (CSCs) are a small tumor cell subpopulation, driving cancer initiation, progression, multidrug resistance, and metastasis. Several methods are used to detect and isolate CSCs by flow cytometry. Among these, measurement of aldehyde dehydrogenase (ALDH) activity within the cell is an assay widely used to identify and isolate CSCs from different types of solid tumors. The aldehyde dehydrogenase (ALDH) is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, overexpressed both in normal and cancer stem cells. In this chapter, it is described how CSCs are detected and isolated by using ALDH activity assay.

ß2-AR inhibition enhances EGFR antibody efficacy hampering the oxidative stress response machinery.

The ß2-Adrenergic receptor (ß2-ARs) is a cell membrane-spanning G protein-coupled receptors (GPCRs) physiologically involved in stress-related response. In many cancers, the ß2-ARs signaling drives the tumor development and transformation, also promoting the resistance to the treatments. In HNSCC cell lines, the ß2-AR selective inhibition synergistically amplifies the cytotoxic effect of the MEK 1/2 by affecting the p38/NF-kB oncogenic pathway and contemporary reducing the NRF-2 mediated antioxidant cell response. In this study, we aimed to validate the anti-tumor effect of ß2-AR blockade and the synergism with MEK/ERK and EGFR pathway inhibition in a pre-clinical orthotopic mouse model of HNSCC. Interestingly, we found a strong ß2-ARs expression in the tumors that were significantly reduced after prolonged treatment with ß2-Ars inhibitor (ICI) and EGFR mAb Cetuximab (CTX) in combination. The ß2-ARs down-regulation correlated in mice with a significant tumor growth delay, together with the MAPK signaling switch-off caused by the blockade of the MEK/ERK phosphorylation. We also demonstrated that the administration of ICI and CTX in combination unbalanced the cell ROS homeostasis by blocking the NRF-2 nuclear translocation with the relative down-regulation of the antioxidant enzyme expression. Our findings highlighted for the first time, in a pre-clinical in vivo model, the efficacy of the ß2-ARs inhibition in the treatment of the HNSCC, remarkably in combination with CTX, which is the standard of care for unresectable HNSCC.

Poly(ε-caprolactone)-poly(ethylene glycol) Tri-Block Copolymer as Quercetin Delivery System for Human Colorectal Carcinoma Cells: Synthesis, Characterization and In Vitro Study.

Quercetin is a hydrophobic molecule with short blood circulation times and instability. The development of a nano-delivery system formulation of quercetin may increase its bioavailability, resulting in greater tumor suppressing effects. Triblock ABA type polycaprolactone-polyethylenglycol- polycaprolactone (PCL-PEG-PCL) copolymers have been synthetized using ring-opening polymerization of caprolactone from PEG diol. The copolymers were characterized by nuclear magnetic resonance (NMR), diffusion-ordered NMR spectroscopy (DOSY), and gel permeation chromatography (GPC). The triblock copolymers self-assembled in water forming micelles consisting of a core of biodegradable polycaprolactone (PCL) and a corona of polyethylenglycol (PEG). The core-shell PCL-PEG-PCL nanoparticles were able to incorporate quercetin into the core. They were characterized by dynamic light scattering (DLS) and NMR. The cellular uptake efficiency of human colorectal carcinoma cells was quantitatively determined by flow cytometry using nanoparticles loaded with Nile Red as hydrophobic model drug. The cytotoxic effect of quercetin-loaded nanoparticles was evaluated on HCT 116 cells, showing promising results.

Insulitis in Human Type 1 Diabetic Pancreas: From Stem Cell Grafting to Islet Organoids for a Successful Cell-Based Therapy.

Type 1 diabetes (T1D) is an autoimmune disease with immune cells' islet infiltration (called "insulitis"), which leads to beta cell loss. Despite being the critical element of T1D occurrence and pathogenesis, insulitis is often present in a limited percentage of islets, also at diagnosis. Therefore, it is needed to define reproducible methods to detect insulitis and beta-cell decline, to allow accurate and early diagnosis and to monitor therapy. However, this goal is still far due to the morphological aspect of islet microvasculature, which is rather dense and rich, and is considerably rearranged during insulitis. More studies on microvasculature are required to understand if contrast-enhanced ultrasound sonography measurements of pancreatic blood-flow dynamics may provide a clinically deployable predictive marker to predict disease progression and therapeutic reversal in pre-symptomatic T1D patients. Therefore, it is needed to clarify the relation between insulitis and the dynamics of ß cell loss and with coexisting mechanisms of dysfunction, according to clinical stage, as well as the micro vessels' dynamics and microvasculature reorganization. Moreover, the ideal cell-based therapy of T1D should start from an early diagnosis allowing a sufficient isolation of specific Procr+ progenitors, followed by the generation and expansion of islet organoids, which could be transplanted coupled to an immune-regulatory therapy which will permit the maintenance of pancreatic islets and an effective and long-lasting insulitis reversal.

Cytotoxic Potential of the Marine Diatom Thalassiosira rotula: Insights into Bioactivity of 24-Methylene Cholesterol.

Marine microalgae are receiving great interest as sustainable sources of bioactive metabolites for health, nutrition and personal care. In the present study, a bioassay-guided screening allowed identifying an enriched fraction from SPE separation of the methanolic extract of the marine diatom Thalassiosira rotula with a chemically heterogeneous composition of cytotoxic molecules, including PUFAs, the terpene phytol, the carotenoid fucoxanthin and the phytosterol 24-methylene cholesterol (24-MChol). In particular, this latter was the object of deep investigation aimed to gain insight into the mechanisms of action activated in two tumour cell models recognised as resistant to chemical treatments, the breast MCF7 and the lung A549 cell lines. The results of our studies revealed that 24-MChol, in line with the most studied ß-sitosterol (ß-SIT), showed cytotoxic activity in a 3-30 µM range of concentration involving the induction of apoptosis and cell cycle arrest, although differences emerged between the two sterols and the two cancer systems when specific targets were investigated (caspase-3, caspase-9, FAS and TRAIL).

Hyaluronan-Based Gel Promotes Human Dental Pulp Stem Cells Bone Differentiation by Activating YAP/TAZ Pathway.

BACKGROUND: Hyaluronans exist in different forms, accordingly with molecular weight and degree of crosslinking. Here, we tested the capability to induce osteogenic differentiation in hDPSCs (human dental pulp stem cells) of three hyaluronans forms: linear pharmaceutical-grade hyaluronans at high and (HHA) low molecular weight (LHA) and hybrid cooperative complexes (HCC), containing both sizes. METHODS: hDPSCs were treated with HHA, LHA, HCC for 7, 14 and 21 days. The effects of hyaluronans on osteogenic differentiation were evaluated by qRT-PCR and WB of osteogenic markers and by Alizarin Red S staining. To identify the involved pathway, CD44 was analyzed by immunofluorescence, and YAP/TAZ expression was measured by qRT-PCR. Moreover, YAP/TAZ inhibitor-1 was used, and the loss of function of YAP/TAZ was evaluated by qRT-PCR, WB and immunofluorescence. RESULTS: We showed that all hyaluronans improves osteogenesis. Among these, HCC is the main inducer of osteogenesis, along with overexpression of bone related markers and upregulating CD44. We also found that this biological process is subordinate to the activation of YAP/TAZ pathway. CONCLUSIONS: We found that HA's molecular weight can have a relevant impact on HA performance for bone regeneration, and we unveil a new molecular mechanism by which HA acts on stem cells.

ß2-AR blockade potentiates MEK1/2 inhibitor effect on HNSCC by regulating the Nrf2-mediated defense mechanism.

The ß2-Adrenergic receptor (ß2-AR) is a G protein-coupled receptor (GPCR), involved in the development of many cancers, among which HNSCC. In this contest, ß2-AR signaling interacts with different pathways, such as PI3K and MAPK, commonly activated by TK receptors. For this reason, TK blockade is one of the most adopted therapeutic strategies in HNSCC patients. In our study we investigated the effects of the ß2-AR blocking in HNSCC cell lines, using the selective inhibitor ICI118,551 (ICI), in combination with the MAPK inhibitor U0126. We found that ICI leads to the blocking of p38 and NF-kB oncogenic pathways, strongly affecting also the ERK and PI3K pathways. Cotreatment with U0126 displays a synergic effect on cell viability and pathway alteration. Interestingly, we found that the ß2-AR blockade affects Nrf2-Keap1 stability and its nuclear translocation leading to a drastic ROS increase and oxidative stress. Our results are confirmed by a TCGA dataset analysis, showing that NFE2L2 gene is commonly overexpressed in HNSC, and correlated with a lower survival rate. In our system, the PI3K pathway inhibition culminated in the blocking of pro-survival autophagy, a mechanism normally adopted by cancer cells to became less responsive to the therapies. The mTOR expression, commonly upregulated in HNSC, was reduced in patients with disease-recurrence. It is well known that mTOR has a strong autophagy inhibition effect, therefore its downregulation promoted pro-survival autophagy, with a related increase recurrence rate. Our findings highlight for the first time the key role of ß2-AR and related pathway in HNSCC cell proliferation and drug resistance, proposing it as a valuable therapeutic molecular target.

The role of autophagy in resistance to targeted therapies.

Autophagy is a self-degradative cellular process, involved in stress response such as starvation, hypoxia, and oxidative stress. This mechanism balances macro-molecule recycling to regulate cell homeostasis. In cancer, autophagy play a role in the development and progression, while several studies describe it as one of the key processes in drug resistance. In the last years, in addition to standard anti-cancer treatments such as chemotherapies and irradiation, targeted therapy became one of the most adopted strategies in clinical practices, mainly due to high specificity and reduced side effects. However, similar to standard treatments, drug resistance is the main challenge in most patients. Here, we summarize recent studies that investigated the role of autophagy in drug resistance after targeted therapy in different types of cancers. We highlight positive results and limitations of pre-clinical and clinical studies in which autophagy inhibitors are used in combination with targeted therapies.

Dissecting the Potential Roles of Nigella sativa and Its Constituent Thymoquinone on the Prevention and on the Progression of Alzheimer's Disease.

Several nutraceuticals have been investigated for preventing or retarding the progression of different neurodegenerative diseases, including Alzheimer's disease (AD). Because Nigella sativa (NS) and its isolated compound thymoquinone (TQ) have significant anti-oxidant and anti-inflammatory proprieties, they could represent effective neuroprotective agents. The purpose of this manuscript is to analyze and to recapitulate the results of in vitro and in vivo studies on the potential role of NS/TQ in AD's prevention and treatment. The level of evidence for each included animal study has been assessed by using a modified CAMARADES (Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies) 10-item checklist. We used MEDLINE and EMBASE databases to screen relevant articles published up to July 2017. A manual search was also performed. The database search yielded 38 studies, of which 18 were included in this manuscript. Results from these approaches suggest that NS or TQ could represent an effective strategy against AD due to the balancing of oxidative processes and the binding to specific intracellular targets. The overall effects mainly regard the prevention of hippocampal pyramidal cell loss and the increased cognitive functions.

Dissecting the mechanisms and molecules underlying the potential carcinogenicity of red and processed meat in colorectal cancer (CRC): an overview on the current state of knowledge.

Meat is a crucial nutrient for human health since it represents a giant supply of proteins, minerals, and vitamins. On the opposite hand, the intake of red and processed meat is taken into account dangerous due to its potential of carcinogenesis and cancer risk improvement, particularly for colorectal cancer (CRC), although it has been reported that also the contaminations of beef infected by oncogenic bovine viruses could increase colorectal cancer's risk. Regarding the mechanisms underlying the potential carcinogenicity of red and processed meat, different hypotheses have been proposed. A suggested mechanism describes the potential role of the heterocyclic amines (HACs) and polycyclic aromatic hydrocarbons (PHAs) in carcinogenesis induced by DNA mutation. Another hypothesis states that heme, through the lipid peroxidation process and therefore the formation of N-nitroso compounds (NOCs), produces cytotoxic and genotoxic aldehydes, resulting in carcinogenesis. Furthermore, a recent proposed hypothesis, is based on the combined actions between the N-Glycolylneuraminic acid (Neu5Gc) and genotoxic compounds. The purpose of this narrative review is to shed a light on the mechanisms underlying the potential carcinogenicity of red and processed meat, by summarizing the data reported in literature on this topic.

The effects of naloxone on human breast cancer progression: in vitro and in vivo studies on MDA.MB231 cells.

BACKGROUND: Naloxone is viewed as a specific competitive opioid antagonist acting at the level of opioid receptors (µ, δ, and κ) with blended agonist-adversary or agonist action. The role of naloxone in tumor cell growth has been poorly studied in human cancer cell lines. MATERIALS AND METHODS: In the present study, we report findings from in vitro and in vivo experiments performed to evaluate the effects of naloxone on human breast cancer cell growth and progression. In vitro assays were conducted on estrogen receptor-negative human breast carcinoma cells, MDA.MB231, treated with naloxone at different concentrations (10-100 µM). In vivo experiments were performed on a mouse model of human triple-negative breast cancer generated by using MDA.MB231 injected subcutaneously in mice. Naloxone was daily intraperitoneally injected in mice at 0.357 mg/kg for 2 weeks and at 0.714 mg/kg for the next 2 weeks. Microvessels formation was detected by fluorescein isothiocyanate-dextran (100 µL) injected into the tail vein of mice and confirmed by immunohistochemistry with CD31 on mice tumor sections. RESULTS: In vitro tests showed that the cell proliferation of MDA.MB231 was inhibited by naloxone in a dose-dependent manner, whereas the cell death was increased. In vivo studies demonstrated that tumors of mice treated with naloxone were significantly smaller than those observed in the control groups, as long as naloxone was administered. Finally, naloxone was not able to impair the microvessel formation in tumors of treated mice. CONCLUSION: Our data showed, for the first time, that naloxone reduced breast cancer progression without affecting angiogenesis.

Phosphonium Salt Displays Cytotoxic Effects Against Human Cancer Cell Lines.

Aims/Objective: Phosphonium salts are compounds whose structural characteristics enable them to cross the plasma and mitochondrial membrane with ease. Cancer cells have higher plasma membrane potentials than normal cells; phosphonium salts selectively accumulate in the mitochondria of neoplastic cells and inhibit mitochondrial function. METHOD: In the present work, we investigated the cytotoxic activity of lipophilic phosphonium salt (11- methoxy11-oxo-undecyl) triphenylphosphonium bromide (MUTP) as well as of the two new phosphine oxide salts, 3,3'-(methylphosphoryl) dibenzenaminium chloride (SBAMPO) and 3,3' (phenylphosphoryl) dibenzenaminium chloride (SBAPPO) on the proliferation of breast cancer cell line (MCF-7) and human uterin cervix adenocarcinoma cells (HeLa). RESULT: We showed that only MUTP exhibits antiproliferative effects on both cell lines, without affecting the normal breast epithelial cell proliferation. More specifically, we demonstrated that MUTP treatment of breast cancer cells is associated with impaired cell-cycle progression and metabolically induces mitochondrial damage and triggers apoptotic cell death in MCF-7 and HeLa cells. Taken together, these findings suggest that MUTP may be capable of selectively targeting neoplastic cell growth and therefore has potential applications as anticancer agent.

Role of Nigella sativa and Its Constituent Thymoquinone on Chemotherapy-Induced Nephrotoxicity: Evidences from Experimental Animal Studies.

BACKGROUND: Most chemotherapeutic drugs are known to cause nephrotoxicity. Therefore, new strategies have been considered to prevent chemotherapy-induced nephrotoxicity. It is of note that Nigella sativa (NS), or its isolated compound Thymoquinone (TQ), has a potential role in combating chemotherapy-induced nephrotoxicity. AIM: To analyze and report the outcome of experimental animal studies on the protective effects of NS/TQ on chemotherapy-associated kidney complications. DESIGN: Standard systematic review and narrative synthesis. DATA SOURCES: MEDLINE, EMBASE databases were searched for relevant articles published up to March 2017. Additionally, a manual search was performed. Criteria for a study's inclusion were: conducted in animals, systematic reviews and meta-analysis, containing data on nephroprotective effects of NS/TQ compared to a placebo or other substance. All strains and genders were included. RESULTS: The database search yielded 71 studies, of which 12 (cisplatin-induced nephrotoxicity 8; methotrexate-induced nephrotoxicity 1; doxorubicin-induced nephrotoxicity 2; ifosfamide-induced nephrotoxicity 1) were included in this review. CONCLUSIONS: Experimental animal studies showed the protective effect of NS, or TQ, on chemotherapy-induced nephrotoxicity. These effects are caused by decreasing lipid peroxidation and increasing activity of antioxidant enzymes in renal tissue of chemotherapy-treated animals.

Anticancer and Anti-Inflammatory Properties of Ganoderma lucidum Extract Effects on Melanoma and Triple-Negative Breast Cancer Treatment.

Among the most important traditional medicinal fungi, Ganoderma lucidum has been used as a therapeutic agent for the treatment of numerous diseases, including cancer, in Oriental countries. The aim of this study is to investigate the anti-inflammatory, anticancer and anti-metastatic activities of Ganoderma lucidum extracts in melanoma and triple-negative breast cancer cells. Ganoderma lucidum extracts were prepared by using common organic solvents; MDA-MB 231 and B16-F10 cell lines were adopted as cellular models for triple-negative breast cancer and melanoma and characterized for cell viability, wound-healing assay and measurement of cytokines secreted by cancer cells under pro-inflammatory conditions (incubation with lipopolysaccharide, LPS) and pretreatment with Ganoderma lucidum extract at different concentrations. Our study demonstrates, for the first time, how Ganoderma lucidum extracts can significantly inhibit the release of IL-8, IL-6, MMP-2 and MMP-9 in cancer cells under pro-inflammatory condition. Interestingly, Ganoderma lucidum extracts significantly also decrease the viability of both cancer cells in a time- and concentration-dependent manner, with abilities to reduce cell migration over time, which is correlated with a lower release of matrix metalloproteases. Taken together, these results indicate the possible use of Ganoderma lucidum extract for the therapeutic management of melanoma and human triple-negative breast cancer.

Synthesis and Antitumor Activity of New Group 3 Metallocene Complexes.

The quest for alternative drugs with respect to the well-known cis-platin and its derivatives, which are still used in more than 50% of the treatment regimens for patients suffering from cancer, is highly needed. In this context, organometallic compounds, which are defined as metal complexes containing at least one direct covalent metal-carbon bond, have recently been found to be promising anticancer drug candidates. A series of new metallocene complexes with scandium, yttrium, and neodymium have been prepared and characterized. Some of these compounds show a very interesting anti-proliferative activity in triple negative breast cancer cell line (MDA.MB231) and the non-hormone sensitive prostate cancer cell line (DU145). Moreover, the interaction of some of them with biological membranes, evaluated using liposomes as bio-membrane mimetic model systems, seems to be relevant. The biological activity of these compounds, particularly those based on yttrium, already effective at low concentrations on both cancer cell lines, should be taken into account with regard to new therapeutic approaches in anticancer therapy.

Mouse Models in Prostate Cancer Translational Research: From Xenograft to PDX.

Despite the advancement of clinical and preclinical research on PCa, which resulted in the last five years in a decrement of disease incidence by 3-4%, it remains the most frequent cancer in men and the second for mortality rate. Based on this evidence we present a brief dissertation on numerous preclinical models, comparing their advantages and disadvantages; among this we report the PDX mouse models that show greater fidelity to the disease, in terms of histopathologic features of implanted tumor, gene and miRNA expression, and metastatic pattern, well describing all tumor progression stages; this characteristic encourages the translation of preclinical results. These models become particularly useful in meeting the need of new treatments identification that eradicate PCa bone metastases growing, clarifying pathway of angiogenesis, identifying castration-resistant stem-like cells, and studying the antiandrogen therapies. Also of considerable interest are the studies of 3D cell cultures derived from PDX, which have the ability to maintain PDX cell viability with continued native androgen receptor expression, also showing a differential sensitivity to drugs. 3D PDX PCa may represent a diagnostic platform for the rapid assessment of drugs and push personalized medicine. Today the development of preclinical models in vitro and in vivo is necessary in order to obtain increasingly reliable answers before reaching phase III of the drug discovery.

The Therapeutic Targets of miRNA in Hepatic Cancer Stem Cells.

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide malignancy and the third leading cause of cancer death in patients. Several studies demonstrated that hepatic cancer stem cells (HCSCs), also called tumor-initiating cells, are involved in regulation of HCC initiation, tumor progression, metastasis development, and drug resistance. Despite the extensive research, the underlying mechanisms by which HCSCs are regulated remain still unclear. MicroRNAs (miRNAs) are able to regulate a lot of biological processes such as self-renewal and pluripotency of HCSCs, representing a new promising strategy for treatment of HCC chemotherapy-resistant tumors. In this review, we synthesize the latest findings on therapeutic regulation of HCSCs by miRNAs, in order to highlight the perspective of novel miRNA-based anticancer therapies for HCC treatment.

Electrochemotherapy in pancreatic adenocarcinoma treatment: pre-clinical and clinical studies.

BACKGROUND: Pancreatic adenocarcinoma is currently one of the deadliest cancers with high mortality rate. This disease leads to an aggressive local invasion and early metastases, and is poorly responsive to treatment with chemotherapy or chemo-radiotherapy. Radical resection is still the only curative treatment for pancreatic cancer, but it is generally accepted that a multimodality strategy is necessary for its management. Therefore, new alternative therapies have been considered for local treatment. CONCLUSIONS: Chemotherapeutic resistance in pancreatic cancer is associated to a low penetration of drugs into tumour cells due to the presence of fibrotic stroma surrounding cells. In order to increase the uptake of chemotherapeutic drugs into tumour cells, electrochemotherapy can be used for treatment of pancreatic adenocarcinoma leading to an increased tumour response rate. This review will summarize the published papers reported in literature on the efficacy and safety of electrochemotherapy in pre-clinical and clinical studies on pancreatic cancer.

The Role of miRNAs in the Regulation of Pancreatic Cancer Stem Cells.

Pancreatic ductal adenocarcinoma is currently one of the deadliest cancers with low overall survival rate. This disease leads to an aggressive local invasion and early metastases and is poorly responsive to treatment with chemotherapy or chemoradiotherapy. Several studies have shown that pancreatic cancer stem cells (PCSCs) play different roles in the regulation of drug resistance and recurrence in pancreatic cancer. MicroRNA (miRNA), a class of newly emerging small noncoding RNAs, is involved in the modulation of several biological activities ranging from invasion to metastases development, as well as drug resistance of pancreatic cancer. In this review, we synthesize the latest findings on the role of miRNAs in regulating different biological properties of pancreatic cancer stem cells.