Targeting cancer stem cells and signaling pathways by phytochemicals: Novel approach for breast cancer therapy

Natural Products-Based Nanoformulations: A New Approach Targeting CSCs to Cancer Therapy

Cancer stem cells (CSCs) lead to the occurrence and progression of cancer due to their strong tumorigenic, self-renewal, and multidirectional differentiation abilities. Existing cancer treatment methods cannot effectively kill or inhibit CSCs but instead enrich them and produce stronger proliferation, invasion, and metastasis capabilities, resulting in cancer recurrence and treatment resistance, which has become a difficult problem in clinical treatment. Therefore, targeting CSCs may be the most promising approach for comprehensive cancer therapy in the future. A variety of natural products (NP) have significant antitumor effects and have been identified to target and inhibit CSCs. However, pharmacokinetic defects and off-target effects have greatly hindered their clinical translation. NP-based nanoformulations (NPNs) have tremendous potential to overcome the disadvantages of NP against CSCs through site-specific delivery and by improving their pharmacokinetic parameters. In this review, we summarize the recent progress of NPNs targeting CSCs in cancer therapy, looking forward to transforming preclinical research results into clinical applications and bringing new prospects for cancer treatment.

An explorative study for leveraging transcriptomic data of embryonic stem cells in mining cancer stemness genes, regulators, and networks

Due to the exquisite ability of cancer stemness to facilitate tumor initiation, metastasis, and cancer therapy resistance, targeting cancer stemness is expected to have clinical implications for cancer treatment. Genes are fundamental for forming and maintaining stemness. Considering shared genetic programs and pathways between embryonic stem cells and cancer stem cells, we conducted a study analyzing transcriptomic data of embryonic stem cells for mining potential cancer stemness genes. Firstly, we integrated co-expression and regression models and predicted 820 stemness genes. Results of gene enrichment analysis confirmed the good prediction performance for enriched signatures in cancer stem cells. Secondly, we provided an application case using the predicted stemness genes to construct a breast cancer stemness network. Mining on the network identified CD44, SOX2, TWIST1, and DLG4 as potential regulators of breast cancer stemness. Thirdly, using the signature of 31,028 chemical perturbations and their correlation with stemness marker genes, we predicted 67 stemness inhibitors with reasonable accuracy of 78%. Two drugs, namely Rigosertib and Proscillaridin A, were first identified as potential stemness inhibitors for melanoma and colon cancer, respectively. Overall, mining embryonic stem cell data provides a valuable way to identify cancer stemness regulators.

Identification of EZH2 as Cancer Stem Cell Marker in Clear Cell Renal Cell Carcinoma and the Anti-Tumor Effect of Epigallocatechin-3-Gallate (EGCG)

The aim of the study was to develop a new therapeutic strategy to target cancer stem cells (CSCs) in clear cell renal cell carcinoma (ccRCC) and to identify typical CSC markers to improve therapy effectiveness. It was found that the corrected-mRNA expression-based stemness index was upregulated in kidney renal clear cell carcinoma (KIRC) tissues compared to non-tumor tissue and increased with higher tumor stage and grade. EZH2 was identified as a CSC marker and prognosis factor for KIRC patients. The expression of EZH2 was associated with several activated tumor-infiltrating immune cells. High expression of EZH2 was enriched in immune-related pathways, low expression was related to several metabolic pathways. Epigallocatechin-3-gallate (EGCG) was identified as the most potent suppressor of EZH2, was able to inhibit viability, migration, and invasion, and to increase the apoptosis rate of ccRCC CSCs. KIF11, VEGF, and MMP2 were identified as predictive EGCG target genes, suggesting a potential mechanism of how EZH2 might regulate invasiveness and migration. The percentages of FoxP3+ Treg cells in the peripheral blood mononuclear cells of ccRCC patients decreased significantly when cultured with spheres pretreated with EGCG plus sunitinib compared to spheres without treatment. Our findings provide new insights into the treatment options of ccRCC based on targeting CSCs.

Fate decisions of breast cancer stem cells in cancer progression

Breast cancer has a marked recurrence and metastatic trait and is one of the most prevalent malignancies affecting women’s health worldwide. Tumor initiation and progression begin after the cell goes from a quiescent to an activated state and requires different mechanisms to act in concert to regulate t a specific set of spectral genes for expression. Cancer stem cells (CSCs) have been proven to initiate and drive tumorigenesis due to their capability of self-renew and differentiate. In addition, CSCs are believed to be capable of causing resistance to anti-tumor drugs, recurrence and metastasis. Therefore, exploring the origin, regulatory mechanisms and ultimate fate decision of CSCs in breast cancer outcomes has far-reaching clinical implications for the development of breast cancer stem cell (BCSC)-targeted therapeutic strategies. In this review, we will highlight the contribution of BCSCs to breast cancer and explore the internal and external factors that regulate the fate of BCSCs.

Drug and apoptosis resistance in cancer stem cells: a puzzle with many pieces

Resistance to anticancer agents and apoptosis results in cancer relapse and is associated with cancer mortality. Substantial data have provided convincing evidence establishing that human cancers emerge from cancer stem cells (CSCs), which display self-renewal and are resistant to anticancer drugs, radiation, and apoptosis, and express enhanced epithelial to mesenchymal progression. CSCs represent a heterogeneous tumor cell population and lack specific cellular targets, which makes it a great challenge to target and eradicate them. Similarly, their close relationship with the tumor microenvironment creates greater complexity in developing novel treatment strategies targeting CSCs. Several mechanisms participate in the drug and apoptosis resistance phenotype in CSCs in various cancers. These include enhanced expression of ATP-binding cassette membrane transporters, activation of various cytoprotective and survival signaling pathways, dysregulation of stemness signaling pathways, aberrant DNA repair mechanisms, increased quiescence, autophagy, increased immune evasion, deficiency of mitochondrial-mediated apoptosis, upregulation of anti-apoptotic proteins including c-FLIP [cellular FLICE (FADD-like IL-1β-converting enzyme)-inhibitory protein], Bcl-2 family members, inhibitors of apoptosis proteins, and PI3K/AKT signaling. Studying such mechanisms not only provides mechanistic insights into these cells that are unresponsive to drugs, but may lead to the development of targeted and effective therapeutics to eradicate CSCs. Several studies have identified promising strategies to target CSCs. These emerging strategies may help target CSC-associated drug resistance and metastasis in clinical settings. This article will review the CSCs drug and apoptosis resistance mechanisms and how to target CSCs.

A dual-responsive "Yin-Yang" photothermal delivery system to accelerate Parthenolide anti-tumor efficacy

Parthenolide (PTL), a germacrane sesquiterpene lactone extracted from the "Yin" Chinese traditional herb feverfew, has gained interest due to its lethal effects on tumor cells and its pharmacological effects within traditional Chinese medicine theory. To overcome low, non-targeted accumulation and uncontrolled release of PTL administration, a dual-responsive PTL-liposomes@chitosan@gold nanoshells (PTL-Lips@CS@GNS) system was fabricated. Hyperthermia generated under light irradiation in the near-infrared region via local surface plasmon resonance of gold nanoshells induced photothermal therapy, which also stimulated PTL release due to the liposomes gel-to-liquid crystalline phase transition. Additionally, PTL-Lips@CS@GNS exhibited a pH-responsive release in the acidic tumor microenvironment. Collectively, this study provides a realistic strategy for an effective combination of traditional Chinese medicine and current nanotechnology for tumor therapy.

Targeting Breast Cancer Stem Cells Using Naturally Occurring Phytoestrogens

Breast cancer therapies have made significant strides in improving survival for patients over the past decades. However, recurrence and drug resistance continue to challenge long-term recurrence-free and overall survival rates. Mounting evidence supports the cancer stem cell model in which the existence of a small population of breast cancer stem cells (BCSCs) within the tumor enables these cells to evade conventional therapies and repopulate the tumor, giving rise to more aggressive, recurrent tumors. Thus, successful breast cancer therapy would need to target these BCSCs, as well the tumor bulk cells. Since the Women’s Health Initiative study reported an increased risk of breast cancer with the use of conventional hormone replacement therapy in postmenopausal women, many have turned their attention to phytoestrogens as a natural alternative. Phytoestrogens are plant compounds that share structural similarities with human estrogens and can bind to the estrogen receptors to alter the endocrine responses. Recent studies have found that phytoestrogens can also target BCSCs and have the potential to complement conventional therapy eradicating BCSCs. This review summarized the latest findings of different phytoestrogens and their effect on BCSCs, along with their mechanisms of action, including selective estrogen receptor binding and inhibition of molecular pathways used by BCSCs. The latest results of phytoestrogens in clinical trials are also discussed to further evaluate the use of phytoestrogen in the treatment and prevention of breast cancer.

An Integrative Pan-Cancer Analysis Revealing MLN4924 (Pevonedistat) as a Potential Therapeutic Agent Targeting Skp2 in YAP-Driven Cancers

Background: YAP, coded by YAP1 gene, is critical in the Hippo pathway. It has been reported to be involved in the tumorigenesis and progression of several cancers. However, its roles on tumor cell proliferation in diverse cancers remain to be elucidated. And there is currently no clinically feasible drug that can directly target YAP in cancers. This research aimed to explore the regulatory mechanism of YAP in promoting tumor proliferation of multiple cancers, in order to find new strategies for inhibiting the overgrowth of YAP-driven cancers.

Methods: We investigated the expression pattern of YAP1 in pan-cancer across numerous databases and our cohorts. First, univariate Cox regression analysis and survival analysis were used to evaluate the effect of YAP1 on the prognosis of cancer patients. Second, TIMER was used to explore the relationship between YAP1 expression and tumor cell proliferation. Third, functional and pathway enrichment was performed to search for targets of YAP involved in cell cycle in cancers. At last, GDSC and CCLE datasets were used to assess the correlation between SKP2 expression and MLN4924 IC50 values.

Results: Differential expression analysis of multiple databases and qPCR validation showed that YAP1 was generally overexpressed in pan-cancers. Survival analysis revealed that YAP1 over-expression was significantly related to poor prognosis of patients with PAAD. The expression level of YAP1 was positively correlated with the proliferation in varieties of tumors. Further, SKP2 was confirmed as a target of YAP in promoting tumor cell proliferation. In addition, SKP2 expression was negatively correlated with MLN4924 IC50 values in almost all cancer types.

Conclusion:YAP1 is frequently overexpressed in human cancers. YAP promoted tumor cell proliferation by up-regulating SKP2 expression in multiple cancers. The comprehensive pan-cancer analysis suggested that inhibition of Skp2 with MLN4924 might be an effective therapeutic strategy for attenuating tumor cell proliferation in YAP-driven cancers.

Targeting Breast Cancer-Derived Stem Cells by Dietary Phytochemicals: A Strategy for Cancer Prevention and Treatment

Breast cancer is heterogeneous disease with variable prognosis and therapeutic response. Approximately, 70% of diagnosed breast cancer represents the luminal A subtype. This subpopulation has a fair prognosis with a lower rate of relapse than the other clinical subtypes. Acquisition of stemness in luminal A subtype modifies the phenotype plasticity to accomplish increased aggressiveness and therapeutic resistance. Therefore, targeting luminal A-derived breast cancer stem cells (BCSCs) could be a promising strategy for its prevention and treatment. Extensive studies reveal that dietary phytochemicals have the potential to target BCSCs by modulating the molecular and signal transduction pathways. Dietary phytochemicals alone or in combination with standard therapeutic modalities exert higher efficacy in targeting BCSCs through changes in stemness, self-renewal properties and hypoxia-related factors. These combinations offer achieving higher radio- and chemo- sensitization through alteration in the key signaling pathways such as AMPK, STAT3, NF-ĸB, Hedgehog, PI3K/Akt/mTOR, Notch, GSK3β, and Wnt related to cancer stemness and drug resistance. In this review, we highlight the concept of targeting luminal A-derived BCSCs with dietary phytochemicals by summarizing the pathways and underlying mechanism(s) involved during therapeutic resistance.

Curcumin: reclaiming the lost ground against cancer resistance

Curcumin, a polyphenol, has a wide range of biological properties such as anticancer, antibacterial, antitubercular, cardioprotective and neuroprotective. Moreover, the anti-proliferative activities of Curcumin have been widely studied against several types of cancers due to its ability to target multiple pathways in cancer. Although Curcumin exhibited potent anticancer activity, its clinical use is limited due to its poor water solubility and faster metabolism. Hence, there is an immense interest among researchers to develop potent, water-soluble, and metabolically stable Curcumin analogs for cancer treatment. While drug resistance remains a major problem in cancer therapy that renders current chemotherapy ineffective, curcumin has shown promise to overcome the resistance and re-sensitize cancer to chemotherapeutic drugs in many studies. In the present review, we are summarizing the role of curcumin in controlling the proliferation of drug-resistant cancers and development of curcumin-based therapeutic applications from cell culture studies up to clinical trials.

Phytochemical-conjugated bio-safe gold nanoparticles in breast cancer: a comprehensive update

Breast cancer is the most common malignancy in women and is rated among one of the three common malignancies worldwide in combination with colon and lung cancer. The escalating mortality rate of breast cancer patients has captivated the attention of the present-day researchers to come up with new management options. According to WHO, early detection, timely diagnosis and comprehensive breast cancer management are the three cornerstones for controlling breast cancer incidences per year. Multidisciplinary theragnostic approaches for simultaneous diagnosis and treatment of breast cancer have further enriched the therapeutic arsenal. Imaging and biopsy play a significant role in the diagnosis of breast cancer. The treatment plan mostly initiates with general surgery or radiation therapy followed up with adjuvant and/or neoadjuvant therapy. Conventional chemotherapeutics in breast cancer suffer from toxicity and lack of site specificity. Bio-safe gold nanoparticles hold sufficient promise for bridging this gap. Diverse phytochemicals-based synthesis routes to arrive at nano-dimensional gold with spotlight on reaction mechanisms, reaction variables, specific advantages, toxicity and their influence in breast cancer conditions are the focus of this work. This review marks the first attempt to explore the potential of phytochemical-derived nano-gold in breast cancer treatment.

The Emerging Potential of Parthenolide Nanoformulations in Tumor Therapy

Plant-derived sesquiterpene lactones are promising natural sources for the discovery of anti-cancer drugs. As an extensively studied sesquiterpene lactone, the tumor suppression effect of parthenolide (PTL) has been clarified by targeting a number of prominent signaling pathways and key protein regulators in carcinogenesis. Notably, PTL was also the first small molecule reported to eradicate cancer stem cells. Nevertheless, the clinical application of PTL as an antitumor agent remains limited, owing to some disadvantages such as low water solubility and poor bioavailability. Thus, nanomedicine has attracted much interest because of its great potential for transporting poorly soluble drugs to desired body sites. In view of the significant advantages over their free small-molecule counterparts, nanoparticle delivery systems appear to be a potential solution for addressing the delivery of hydrophobic drugs, including PTL. In this review, we summarized the key anticancer mechanisms underlined by PTL as well as engineered PTL nanoparticles synthesized to date. Therefore, PTL nanoformulations could be an alternative strategy to maximize the therapeutic value of PTL.

Natural Small Molecules in Breast Cancer Treatment: Understandings from a Therapeutic Viewpoint

Breast cancer (BrCa) is the most common malignancy in women and the second most significant cause of death from cancer. BrCa is one of the most challenging malignancies to treat, and it accounts for a large percentage of cancer-related deaths. The number of cases requiring more effective BrCa therapy has increased dramatically. Scientists are looking for more productive agents, such as organic combinations, for BrCa prevention and treatment because most chemotherapeutic agents are linked to cancer metastasis, the resistance of the drugs, and side effects. Natural compounds produced by living organisms promote apoptosis and inhibit metastasis, slowing the spread of cancer. As a result, these compounds may delay the spread of BrCa, enhancing survival rates and reducing the number of deaths caused by BrCa. Several natural compounds inhibit BrCa production while lowering cancer cell proliferation and triggering cell death. Natural compounds, in addition to therapeutic approaches, are efficient and potential agents for treating BrCa. This review highlights the natural compounds demonstrated in various studies to have anticancer properties in BrCa cells. Future research into biological anti-BrCa agents may pave the way for a new era in BrCa treatment, with natural anti-BrCa drugs playing a key role in improving BrCa patient survival rates.

Research Progress of Natural Small-Molecule Compounds Related to Tumor Differentiation

Tumor differentiation is a therapeutic strategy aimed at reactivating the endogenous differentiation program of cancer cells and inducing cancer cells to mature and differentiate into other types of cells. It has been found that a variety of natural small-molecule drugs can induce tumor cell differentiation both in vitro and in vivo. Relevant molecules involved in the differentiation process may be potential therapeutic targets for tumor cells. Compared with synthetic drugs, natural small-molecule antitumor compounds have the characteristics of wide sources, structural diversity and low toxicity. In addition, natural drugs with structural modification and transformation have relatively concentrated targets and enhanced efficacy. Therefore, using natural small-molecule compounds to induce malignant cell differentiation represents a more targeted and potential low-toxicity means of tumor treatment. In this review, we focus on natural small-molecule compounds that induce differentiation of myeloid leukemia cells, osteoblasts and other malignant cells into functional cells by regulating signaling pathways and the expression of specific genes. We provide a reference for the subsequent development of natural small molecules for antitumor applications and promote the development of differentiation therapy.

Celastrol and Resveratrol Modulate SIRT Genes Expression and Exert Anticancer Activity in Colon Cancer Cells and Cancer Stem-like Cells

Simple Summary

The recovery rate in patients with metastatic colorectal cancer (CRC) remains low and declines with successive lines of treatment. This phenomenon is caused by the development of drug resistance and the presence of colorectal cancer stem cells (CSCs). Phytochemicals, like -celastrol and resveratrol, are very promising for colon cancer therapy, owing to their low or no toxicity and their pleiotropic activity, enabling them to interact with various biological targets. In the present study, the potential anticancer mechanisms of both compounds against metastatic colon cancer cells and the capacity to eradicate CSCs were investigated.

Abstract

Metastatic colorectal cancer (CRC) remains a hard-to-cure neoplasm worldwide. Its curability declines with successive lines of treatment due to the development of various cancer resistance mechanisms and the presence of colorectal cancer stem cells (CSCs). Celastrol and resveratrol are very promising phytochemicals for colon cancer therapy, owing to their pleiotropic activity that enables them to interact with various biological targets. In the present study, the anticancer activities of both compounds were investigated in metastatic colon cancer cells (LoVo cells) and cancer stem-like cells (LoVo/DX). We showed that celastrol is a very potent anti-tumor compound against metastatic colon cancer, capable of attenuating CSC-like cells at the molecular and cellular levels. In contrast, resveratrol has a much greater effect on colon cancer cells that are expressing standard sensitivity to anticancer drugs, than on CSC-like cells. In addition, both polyphenols have different influences on the expression of SIRT genes, which seems to be at least partly related to their anti-tumor activity.

Parthenolide and Its Soluble Analogues: Multitasking Compounds with Antitumor Properties

Due to its chemical properties and multiple molecular effects on different tumor cell types, the sesquiterpene lactone parthenolide (PN) can be considered an effective drug with significant potential in cancer therapy. PN has been shown to induce either classic apoptosis or alternative caspase-independent forms of cell death in many tumor models. The therapeutical potential of PN has been increased by chemical design and synthesis of more soluble analogues including dimethylaminoparthenolide (DMAPT). This review focuses on the molecular mechanisms of both PN and analogues action in tumor models, highlighting their effects on gene expression, signal transduction and execution of different types of cell death. Recent findings indicate that these compounds not only inhibit prosurvival transcriptional factors such as NF-κB and STATs but can also determine the activation of specific death pathways, increasing intracellular reactive oxygen species (ROS) production and modifications of Bcl-2 family members. An intriguing property of these compounds is its specific targeting of cancer stem cells. The unusual actions of PN and its analogues make these agents good candidates for molecular targeted cancer therapy.

Polyphenols as the Potential Disease-modifying Therapy in Cancer

BACKGROUND

Disease-modifying therapy in cancer can be defined as long-term treatment that has a beneficial outcome on the course of cancer, affecting the underlying pathophysiology. The anticancer potential of polyphenols is widely studied. However, there is a significant gap between experimental data obtained in vitro and in vivo and the current polyphenol role in cancer therapy.

OBJECTIVE

In this article, the reason for this inconsistency is discussed, which might be in the design of polyphenols clinical trials. The approach of long-term polyphenol disease-modifying therapy in cancer is encouraged.

CONCLUSION

As the physiologic concentrations of polyphenols are not sufficient for reaching the cytotoxic levels, the immune-modulatory effects and effects on cancer intrinsic signal transduction pathways should be considered in polyphenol clinical trials design. Such effects apparently can not cause the rapid regression of the disease. However, more likely, they can modulate the course of the disease, leading to favorable changes in the patient's condition in case of long-term treatment that can be considered to be cancer disease modification.

Functional metabolome profiling may improve individual outcomes in colorectal cancer management implementing concepts of predictive, preventive, and personalized medical approach

Objectives

Colorectal cancer (CRC) is one of the most common solid tumors worldwide, but its diagnosis and treatment are limited. The objectives of our study were to compare the metabolic differences between CRC patients and healthy controls (HC), and to identify potential biomarkers in the serum that can be used for early diagnosis and as effective therapeutic targets. The aim was to provide a new direction for CRC predictive, preventive, and personalized medicine (PPPM).

Methods

In this study, CRC patients (n = 30) and HC (n = 30) were recruited. Serum metabolites were assayed using an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technology. Subsequently, CRC cell lines (HCT116 and HCT8) were treated with metabolites to verify their function. Key targets were identified by molecular docking, thermal shift assay, and protein overexpression/inhibition experiments. The inhibitory effect of celastrol on tumor growth was also assessed, which included IC50 analysis, nude mice xenografting, molecular docking, protein overexpression/inhibition experiments, and network pharmacology technology.

Results

In the CRC group, 15 serum metabolites were significantly different in comparison with the HC group. The level of glycodeoxycholic acid (GDCA) was positively correlated with CRC and showed high sensitivity and specificity for the clinical diagnostic reference (AUC = 0.825). In vitro findings showed that GDCA promoted the proliferation and migration of CRC cell lines (HCT116 and HCT8), and Poly(ADP-ribose) polymerase-1 (PARP-1) was identified as one of the key targets of GDCA. The IC50 of celastrol in HCT116 cells was 121.1 nM, and the anticancer effect of celastrol was supported by in vivo experiments. Based on the potential of GDCA in PPPM, PARP-1 was found to be significantly correlated with the anticancer functions of celastrol.

Conclusion

These findings suggest that GDCA is an abnormally produced metabolite of CRC, which may provide an innovative molecular biomarker for the predictive identification and targeted prevention of CRC. In addition, PARP-1 was found to be an important target of GDCA that promotes CRC; therefore, celastrol may be a potential targeted therapy for CRC via its effects on PARP-1. Taken together, the pathophysiology and progress of tumor molecules mediated by changes in metabolite content provide a new perspective for predictive, preventive, and personalized medical of clinical cancer patients based on the target of metabolites in vivo.Clinical trials registration number: ChiCTR2000039410.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-021-00269-8.

Curcuma longa L. Prevents the Loss of β-Tubulin in the Brain and Maintains Healthy Aging in Drosophila melanogaster

Loss of tubulin is associated with neurodegeneration and brain aging. Turmeric (Curcuma longa L.) has frequently been employed as a spice in curry and traditional medications in the Indian subcontinent to attain longevity and better cognitive performance. We aimed to evaluate the unelucidated mechanism of how turmeric protects the brain to be an anti-aging agent. D. melanogaster was cultured on a regular diet and turmeric-supplemented diet. β-tubulin level and physiological traits including survivability, locomotor activity, fertility, tolerance to oxidative stress, and eye health were analyzed. Turmeric showed a hormetic effect, and 0.5% turmeric was the optimal dose in preventing aging. β-tubulin protein level was decreased in the brain of D. melanogaster upon aging, while a 0.5% turmeric-supplemented diet predominantly prevented this aging-induced loss of β-tubulin and degeneration of physiological traits as well as improved β-tubulin synthesis in the brain of D. melanogaster early to mid-age. The higher concentration (≥ 1%) of turmeric-supplemented diet decreased the β-tubulin level and degenerated many of the physiological traits of D. melanogaster. The turmeric concentration-dependent increase and decrease of β-tubulin level were consistent with the increment and decrement data obtained from the evaluated physiological traits. This correlation demonstrated that turmeric targets β-tubulin and has both beneficial and detrimental effects that depend on the concentration of turmeric. The findings of this study concluded that an optimal dosage of turmeric could maintain a healthy neuron and thus healthy aging, by preventing the loss and increasing the level of β-tubulin in the brain.

Role, molecular mechanism and the potential target of breast cancer stem cells in breast cancer development

Breast cancer (BC) is one of the most common malignant tumors in women globally, and its occurrence has surpassed lung cancer and become the biggest threat for women. At present, breast cancer treatment includes surgical resection or postoperative chemotherapy and radiotherapy. However, tumor relapse and metastasis usually lead to current therapy failure thanks to breast cancer stem cells (BCSCs)-mediated tumorigenicity and drug resistance. Drug resistance is mainly due to the long-term quiescent G0 phase, strong DNA repairability, and high expression of ABC transporter, and the tumorigenicity is reflected in the activation of various proliferation pathways related to BCSCs. Therefore, understanding the characteristics of BCSCs and their intracellular and extracellular molecular mechanisms is crucial for the development of targeted drugs for BCSCs. To this end, we discussed the latest developments in BCSCs research, focusing on the analysis of specific markers, critical signaling pathways that maintain the stemness of BCSCs，such as NOTCH, Wnt/β-catenin, STAT3, Hedgehog, and Hippo-YAP signaling, immunomicroenviroment and summarizes targeting therapy strategies for stemness maintenance and differentiation, which provides a theoretical basis for further exploration of treating breast cancer and preventing relapse derived from BCSCs.

An Updated Review of Tetrodotoxin and Its Peculiarities

Tetrodotoxin (TTX) is a crystalline, weakly basic, colorless organic substance and is one of the most potent marine toxins known. Although TTX was first isolated from pufferfish, it has been found in numerous other marine organisms and a few terrestrial species. Moreover, tetrodotoxication is still an important health problem today, as TTX has no known antidote. TTX poisonings were most commonly reported from Japan, Thailand, and China, but today the risk of TTX poisoning is spreading around the world. Recent studies have shown that TTX-containing fish are being found in other regions of the Pacific and in the Indian Ocean, as well as the Mediterranean Sea. This review aims to summarize pertinent information available to date on the structure, origin, distribution, mechanism of action of TTX and analytical methods used for the detection of TTX, as well as on TTX-containing organisms, symptoms of TTX poisoning, and incidence worldwide.

Ninety-six-hour starved peripheral blood mononuclear cell supernatant inhibited LA7 breast cancer stem cells induced tumor via reduction in angiogenesis and alternations in Gch1 and Spr expressions

Introduction

The microenvironment of solid tumors such as breast cancer is heterogeneous and complex, containing different types of cell, namely, cancer stem cells and immune cells. We previously reported the immunoregulatory behavior of the human immune cell in a solid tumor microenvironment-like culture under serum starvation stress for 96 h. Here, we examined the effect of this culture-derived solution on breast cancer development in rats.

Method

Ninety-six-hour starved PBMCs supernatant (96 h-SPS) was collected after culturing human PBMCs for 96 h under serum starvation condition. Breast cancer stem cells, LA7 cell line, was used for in vitro study by analyzing gene expression status and performing cytotoxicity, proliferation, scratch wound healing assays, followed by in vivo tumor induction in three groups of mature female Sprague Dawley rats. Animals were treated with 96 h-SPS or RPMI and normal saline as control, n = 6 for each group. After biochemical analysis of iron, lactate, and pH levels in the dissected tumors, Ki67 antigen expression, angiogenesis, and necrosis evaluation were carried out. Metabolic-related gene expression was assessed using RT-qPCR. Moreover, 96 h-SPS composition was discovered by Nano-LC-ESI-MS/MS.

Results

96 h-SPS solution reduced the LA7 cell viability, proliferation, and migration and Gch1 and Spr genes expression in vitro (p< 0.05), whereas stemness gene Oct4 was upregulated (p< 0.01). The intracellular lactate was significantly decreased in the 96 h-SPS treated group (p = 0.007). In this group, Gch1 and Spr were significantly downregulated (p< 0.05), whereas the Sox2 and Oct4 expression was not changed significantly. The number of vessels and mitosis (Ki67⁺ cells) in the 96 h-SPS-treated group was significantly reduced (p = 0.024). The increased rate of necrosis in this group was statistically significant (p = 0.04). Last, proteomics analysis revealed candidate effectors' components of 96 h-SPS solution.

Conclusion

96 h-SPS solution may help to prevent cancer stem cell mediated tumor development. This phenomenon could be mediated through direct cytotoxic effects, inhibition of cell proliferation and migration in association with reduction in Gch1 and Spr genes expression, angiogenesis and mitosis rate, and necrosis augmentation. The preliminary data obtained from the present study need to be investigated on a larger scale and can be used as a pilot for further studies on the biology of cancer development.

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.

Effects and mechanisms of dietary bioactive compounds on breast cancer prevention

Breast cancer (BC) is the most often diagnosed cancer among females globally and has become an increasing global health issue over the last decades. Despite the substantial improvement in screening methods for initial diagnosis, effective therapy remains lacking. Still, there has been high recurrence and disease progression after treatment of surgery, endocrine therapy, chemotherapy, and radiotherapy. Considering this view, there is a crucial requirement to develop safe, freely accessible, and effective anticancer therapy for BC. The dietary bioactive compounds as auspicious anticancer agents have been recognized to be active and their implications in the treatment of BC with negligible side effects. Hence, this review focused on various dietary bioactive compounds as potential therapeutic agents in the prevention and treatment of BC with the mechanisms of action. Bioactive compounds have chemo-preventive properties as they inhibit the proliferation of cancer cells, downregulate the expression of estrogen receptors, and cell cycle arrest by inducing apoptotic settings in tumor cells. Therapeutic drugs or natural compounds generally incorporate engineered nanoparticles with ideal sizes, shapes, and enhance their solubility, circulatory half-life, and biodistribution. All data of in vitro, in vivo, and clinical studies of dietary bioactive compounds and their impact on BC were collected from Science Direct, PubMed, and Google Scholar. The data of chemopreventive and anticancer activity of dietary bioactive compounds were collected and orchestrated in a suitable place in the review. These shreds of data will be extremely beneficial to recognize a series of additional diet-derived bioactive compounds to treat BC with the lowest side effects.

Ellagitannins, promising pharmacological agents for the treatment of cancer stem cells

Human tumors comprise subpopulations of cells called cancer stem cells (CSCs) that possess stemness properties. CSCs can initiate tumors and cause recurrence, metastasis and are also responsible for chemo- and radio-resistance. CSCs may use signaling pathways similar to normal stem cells, including Notch, JAK/STAT, Wnt and Hedgehog pathways. Ellagitannins (ETs) are a broad group of substances with chemopreventive and anticancer activities. The antitumor activity of ETs and their derivatives are mainly related to their antiinflammatory capacity. They are therefore able to modulate secretory growth factors and pro-inflammatory mediators such as IL-6, TGF-β, TNF-α, IL-1β and IFN-γ. Evidence suggests that ETs display their anticancer effect by targeting CSCs and disrupting stem cell signaling. However, there are still few studies in this field. Therefore, high-quality studies are needed to firmly establish the clinical efficacy of the ETs on CSCs. This paper reviews the structures, sources and pharmacokinetics of ETs. It also focuses on the function of ETs and their effects on CSCs-related cytokines and the relationship between ETs and signaling pathways in CSCs.

DT389-YP7, a Recombinant Immunotoxin against Glypican-3 That Inhibits Hepatocellular Cancer Cells: An In Vitro Study

Hepatocellular carcinoma (HCC) is one of the high-metastatic types of cancer, and metastasis occurs in one-third of patients with HCC. To maintain the effectiveness of drug compounds on cancer cells and minimize their side effects on normal cells, it is important to use new approaches for overcoming malignancies. Immunotoxins (ITs), an example of such a new approach, are protein-structured compounds consisting of toxic and binding moieties which can specifically bind to cancer cells and efficiently induce cell death. Here, we design and scrutinize a novel immunotoxin against an oncofetal marker on HCC cells. We applied a truncated diphtheria toxin (DT389) without binding domain as a toxin moiety to be fused with a humanized YP7 scFv against a high-expressed Glypican-3 (GPC3) antigen on the surface of HCC cells. Cytotoxic effects of this IT were investigated on HepG2 (GPC3⁺) and SkBr3 (GPC3⁻) cell lines as positive- and negative-expressed GPC3 antigens. The dissociation constant (Kd) was calculated 11.39 nM and 18.02 nM for IT and YP7 scfv, respectively, whereas only IT showed toxic effects on the HepG2 cell line, and decreased cell viability (IC50 = 848.2 ng/mL). Changing morphology (up to 85%), cell cycle arrest at G2 phase (up to 13%), increasing intracellular reactive oxygen species (ROSs) (up to 50%), inducing apoptosis (up to 38% for apoptosis and 23% for necrosis), and an almost complete inhibition of cell movement were other effects of immunotoxin treatment on HepG2 cells, not on SkBr3 cell line. These promising results reveal that this new recombinant immunotoxin can be considered as an option as an HCC inhibitor. However, more extensive studies are needed to accomplish this concept.

Recent insights on tea metabolites, their biosynthesis and chemo-preventing effects: A review

Tea manufactured from the cultivated shoots of Camellia sinensis (L.) O. Kuntze is the most commonly consumed nonalcoholic drink around the world. Tea is an agro-based, environmentally sustainable, labor-intensive, job-generating, and export-oriented industry in many countries. Tea includes phenolic compounds, flavonoids, alkaloids, vitamins, enzymes, crude fibers, protein, lipids, and carbohydrates, among other biochemical constituents. This review described the nature of tea metabolites, their biosynthesis and accumulation with response to various factors. The therapeutic application of various metabolites of tea against microbial diseases, cancer, neurological, and other metabolic disorders was also discussed in detail. The seasonal variation, cultivation practices and genetic variability influence tea metabolite synthesis. Tea biochemical constituents, especially polyphenols and its integral part catechin metabolites, are broadly focused on potential applicability for their action against various diseases. In addition to this, tea also contains bioactive flavonoids that possess health-beneficial effects. The catechin fractions, epigallocatechin 3-gallate and epicatechin 3-gallate, are the main components of tea that has strong antioxidant and medicinal properties. The synergistic function of natural tea metabolites with synthetic drugs provides effective protection against various diseases. Furthermore, the application of nanotechnologies enhanced bioavailability, enhancing the therapeutic potential of natural metabolites against numerous diseases and pathogens.

Cancer stem cells and strategies for targeted drug delivery

Cancer stem cells (CSCs) are a small proportion of cancer cells with high tumorigenic activity, self-renewal ability, and multilineage differentiation potential. Standard anti-tumor therapies including conventional chemotherapy, radiation therapy, and molecularly targeted therapies are not effective against CSCs, and often lead to enrichment of CSCs that can result in tumor relapse. Therefore, it is hypothesized that targeting CSCs is key to increasing the efficacy of cancer therapies. In this review, CSC properties including CSC markers, their role in tumor growth, invasiveness, metastasis, and drug resistance, as well as CSC microenvironment are discussed. Further, CSC-targeted strategies including the use of targeted drug delivery systems are examined.

Proteomics and its applications in breast cancer

Breast cancer is an individually unique, multi-faceted and chameleonic disease, an eternal challenge for the new era of high-integrated precision diagnostic and personalized oncomedicine. Besides traditional single-omics fields (such as genomics, epigenomics, transcriptomics and metabolomics) and multi-omics contributions (proteogenomics, proteotranscriptomics or reproductomics), several new "-omics" approaches and exciting proteomics subfields are contributing to basic and advanced understanding of these "multiple diseases termed breast cancer": phenomics/cellomics, connectomics and interactomics, secretomics, matrisomics, exosomics, angiomics, chaperomics and epichaperomics, phosphoproteomics, ubiquitinomics, metalloproteomics, terminomics, degradomics and metadegradomics, adhesomics, stressomics, microbiomics, immunomics, salivaomics, materiomics and other biomics. Throughout the extremely complex neoplastic process, a Breast Cancer Cell Continuum Concept (BCCCC) has been modeled in this review as a spatio-temporal and holistic approach, as long as the breast cancer represents a complex cascade comprising successively integrated populations of heterogeneous tumor and cancer-associated cells, that reflect the carcinoma's progression from a "driving mutation" and formation of the breast primary tumor, toward the distant secondary tumors in different tissues and organs, via circulating tumor cell populations. This BCCCC is widely sustained by a Breast Cancer Proteomic Continuum Concept (BCPCC), where each phenotype of neoplastic and tumor-associated cells is characterized by a changing and adaptive proteomic profile detected in solid and liquid minimal invasive biopsies by complex proteomics approaches. Such a profile is created, beginning with the proteomic landscape of different neoplastic cell populations and cancer-associated cells, followed by subsequent analysis of protein biomarkers involved in epithelial-mesenchymal transition and intravasation, circulating tumor cell proteomics, and, finally, by protein biomarkers that highlight the extravasation and distant metastatic invasion. Proteomics technologies are producing important data in breast cancer diagnostic, prognostic, and predictive biomarkers discovery and validation, are detecting genetic aberrations at the proteome level, describing functional and regulatory pathways and emphasizing specific protein and peptide profiles in human tissues, biological fluids, cell lines and animal models. Also, proteomics can identify different breast cancer subtypes and specific protein and proteoform expression, can assess the efficacy of cancer therapies at cellular and tissular level and can even identify new therapeutic target proteins in clinical studies.

High-Throughput In Vitro Gene Expression Profile to Screen of Natural Herbals for Breast Cancer Treatment

Breast cancer has surpassed lung cancer as the most commonly diagnosed cancer in women worldwide. Some therapeutic drugs and approaches could cause side effects and weaken the immune system. The combination of conventional therapies and traditional Chinese medicine (TCM) significantly improves treatment efficacy in breast cancer. However, the chemical composition and underlying anti-tumor mechanisms of TCM still need to be investigated. The primary aim of this study is to provide unique insights to screen the natural components for breast cancer therapy using high-throughput transcriptome analysis. Differentially expressed genes were identified based on two conditions: single samples and groups were classified according to their pharmaceutical effect. Subsequently, the sample treated with E. cochinchinensis Lour. generated the most significant DEGs set, including 1,459 DEGs, 805 upregulated and 654 downregulated. Similarly, group 3 treatment contained the most DEGs (414 DEGs, 311 upregulated and 103 downregulated). KEGG pathway analyses showed five significant pathways associated with the inflammatory and metastasis processes in cancer, which include the TNF, IL−17, NF-kappa B, MAPK signaling pathways, and transcriptional misregulation in cancer. Samples were classified into 13 groups based on their pharmaceutical effects. The results of the KEGG pathway analyses remained consistent with signal samples; group 3 presents a high significance. A total of 21 genes were significantly regulated in these five pathways, interestingly, IL6, TNFAIP3, and BRIC3 were enriched on at least two pathways, seven genes (FOSL1, S100A9, CXCL12, ID2, PRS6KA3, AREG, and DUSP6) have been reported as the target biomarkers and even the diagnostic tools in cancer therapy. In addition, weighted correlation network analysis (WGCNA) was used to identify 18 modules. Among them, blue and thistle2 were the most relevant modules. A total of 26 hub genes in blue and thistle2 modules were identified as the hub genes. In conclusion, we screened out three new TCM (R. communis L., E. cochinchinensis Lour., and B. fruticosa) that have the potential to develop natural drugs for breast cancer therapy, and obtained the therapeutic targets.

High-Throughput Screen of Natural Compounds and Biomarkers for NSCLC Treatment by Differential Expression and Weighted Gene Coexpression Network Analysis (WGCNA)

Lung cancer is known as the leading cause which presents the highest fatality rate worldwide; non-small-cell lung cancer (NSCLC) is the most prevalent type of lung carcinoma with high severity and affects 80% of patients with lung malignancies. Up to now, the general treatment for NSCLC includes surgery, chemotherapy, and radiotherapy; however, some therapeutic drugs and approaches could cause side effects and weaken the immune system. The combination of conventional therapies and traditional Chinese medicine (TCM) significantly improves treatment efficacy in lung cancer. Therefore, it is necessary to investigate the chemical composition and underlying antitumor mechanisms of TCM, so as to get a better understanding of the potential natural ingredient for lung cancer treatment. In this study, we selected 78 TCM to treat NSCLC cell line (A549) and obtained 92 transcriptome data; differential expression and WGCNA were applied to screen the potential natural ingredient and target genes. The sample which was treated with A. pierreana generated the most significant DEG set, including 6130 DEGs, 2479 upregulated, and 3651 downregulated. KEGG pathway analyses found that four pathways (MAPK, NF-kappa B, p53, and TGF-beta signaling pathway) were significantly enriched; 16 genes were significantly regulated in these four pathways. Interestingly, some of them such as EGFR, DUSP4, IL1R1, IL1B, MDM2, CDKNIA, and IDs have been used as the target biomarkers for cancer diagnosis and therapy. In addition, classified samples into 14 groups based on their pharmaceutical effects, WGCNA was used to identify 27 modules. Among them, green and darkgrey were the most relevant modules. Eight genes in the green module and four in darkgrey were identified as hub genes. In conclusion, we screened out three new TCM (B. fruticose, A. pierreana, and S. scandens) that have the potential to develop natural anticancer drugs and obtained the therapeutic targets for NSCLC therapy. Our study provides unique insights to screen the natural components for NSCLC therapy using high-throughput transcriptome analysis.

Cross-Talk between Oxidative Stress and m6A RNA Methylation in Cancer

Oxidative stress is a state of imbalance between oxidation and antioxidation. Excessive ROS levels are an important factor in tumor development. Damage stimulation and excessive activation of oncogenes cause elevated ROS production in cancer, accompanied by an increase in the antioxidant capacity to retain redox homeostasis in tumor cells at an increased level. Although moderate concentrations of ROS produced in cancer cells contribute to maintaining cell survival and cancer progression, massive ROS accumulation can exert toxicity, leading to cancer cell death. RNA modification is a posttranscriptional control mechanism that regulates gene expression and RNA metabolism, and m⁶A RNA methylation is the most common type of RNA modification in eukaryotes. m⁶A modifications can modulate cellular ROS levels through different mechanisms. It is worth noting that ROS signaling also plays a regulatory role in m⁶A modifications. In this review, we concluded the effects of m⁶A modification and oxidative stress on tumor biological functions. In particular, we discuss the interplay between oxidative stress and m⁶A modifications.

Antiangiogenic role of natural flavonoids and their molecular mechanism: an update

Background

Angiogenesis is the development of new blood vessels from the existing vasculature, which is important in normal developmental processes. Angiogenesis is a key step in tumor growth, invasion, and metastasis. Angiogenesis is necessary for the proper nourishment and removal of metabolic wastes from tumor sites. Therefore, modulation of angiogenesis is considered a therapeutic strategy of great importance for human health.

Main body

Numerous bioactive plant compounds are recently tested for their antiangiogenic potential. Among the most frequently studied are flavonoids which are abundantly present in fruits and vegetables. Flavonoids inhibit angiogenesis and metastasis through the regulation of multiple signaling pathways. Flavonoids regulate the expression of VEGF, matrix metalloproteinases (MMPs), EGFR, and inhibit NFB, PI3-K/Akt, and ERK1/2 signaling pathways, thereby causing strong antiangiogenic effects. This present review aimed to provide up-to-date information on the molecular mechanisms of antiangiogenic properties of natural flavonoids.

Conclusion

Presently developed antiangiogenic drugs in malignant growth treatment do not meet assumptions about adequacy and safety. So further investigations are needed in this field in the future. More recently, flavonoids are the most effective antiangiogenic agent, by inhibition of signaling pathways.

The plasticity of pancreatic cancer stem cells: implications in therapeutic resistance

The ever-growing perception of cancer stem cells (CSCs) as a plastic state rather than a hardwired defined entity has evolved our understanding of the functional and biological plasticity of these elusive components in malignancies. Pancreatic cancer (PC), based on its biological features and clinical evolution, is a prototypical example of a CSC-driven disease. Since the discovery of pancreatic CSCs (PCSCs) in 2007, evidence has unraveled their control over many facets of the natural history of PC, including primary tumor growth, metastatic progression, disease recurrence, and acquired drug resistance. Consequently, the current near-ubiquitous treatment regimens for PC using aggressive cytotoxic agents, aimed at ‘‘tumor debulking’’ rather than eradication of CSCs, have proven ineffective in providing clinically convincing improvements in patients with this dreadful disease. Herein, we review the key hallmarks as well as the intrinsic and extrinsic resistance mechanisms of CSCs that mediate treatment failure in PC and enlist the potential CSC-targeting ‘natural agents’ that are gaining popularity in recent years. A better understanding of the molecular and functional landscape of PCSC-intrinsic evasion of chemotherapeutic drugs offers a facile opportunity for treating PC, an intractable cancer with a grim prognosis and in dire need of effective therapeutic advances.

Synthesis and Bio-evaluation of 2-Alkyl Substituted Fluorinated Genistein Analogues Against Breast Cancer

BACKGROUND

Breast cancer is the leading cause of cancer death in women. The current methods of chemotherapy for breast cancer generally have strong adverse reactions and drug resistance. Therefore, the discovery of novel anti-breast cancer lead compounds is urgently needed.

OBJECTIVE

Design and synthesize a series of 2-alkyl substituted fluorinated genistein analogues and evaluate their anti-breast cancer activity.

METHODS

Target compounds were obtained in a multistep reaction synthesis. The anti-tumor activity of compounds I-1~I-35 were evaluated with MCF-7, MDA-MB-231, MDA-MB-435, and MCF-10A cell lines in vitro, with tamoxifen as the positive control. Molecular docking was used to study the interaction between the synthesized compounds and PI3K-gamma.

RESULTS

A series of 2-alkyl substituted fluorinated genistein analogues were designed, synthesized and screened for their bioactivity. Most of the compounds displayed better selectivity toward breast cancer cell lines as compared with tamoxifen. Among these analogues, I-2, I-3, I-4, I-9, I-15 and I-17 have the strongest selective inhibition of breast cancer cells. Compounds I-10, I-13, I-15, I-17 and I-33 were found to have significant inhibitory effects on breast cancer cells. Molecular docking studies have shown that these compounds may act as PI3Kγ inhibitors and may further exhibit anti-breast cancer effects.

CONCLUSION

Most of the newly synthesized compounds could highly selectively inhibit breast cancer cell lines. The experimental results indicate that the synthesized analogs may also have obvious selective inhibitory effects on other malignant proliferation cancer cells.

Exploring the Biological Activity and Mechanism of Xenoestrogens and Phytoestrogens in Cancers: Emerging Methods and Concepts

Xenoestrogens and phytoestrogens are referred to as "foreign estrogens" that are produced outside of the human body and have been shown to exert estrogen-like activity. Xenoestrogens are synthetic industrial chemicals, whereas phytoestrogens are chemicals present in the plant. Considering that these environmental estrogen mimics potentially promote hormone-related cancers, an understanding of how they interact with estrogenic pathways in human cells is crucial to resolve their possible impacts in cancer. Here, we conducted an extensive literature evaluation on the origins of these chemicals, emerging research techniques, updated molecular mechanisms, and ongoing clinical studies of estrogen mimics in human cancers. In this review, we describe new applications of patient-derived xenograft (PDX) models and single-cell RNA sequencing (scRNA-seq) techniques in shaping the current knowledge. At the molecular and cellular levels, we provide comprehensive and up-to-date insights into the mechanism of xenoestrogens and phytoestrogens in modulating the hallmarks of cancer. At the systemic level, we bring the emerging concept of window of susceptibility (WOS) into focus. WOS is the critical timing during the female lifespan that includes the prenatal, pubertal, pregnancy, and menopausal transition periods, during which the mammary glands are more sensitive to environmental exposures. Lastly, we reviewed 18 clinical trials on the application of phytoestrogens in the prevention or treatment of different cancers, conducted from 2002 to the present, and provide evidence-based perspectives on the clinical applications of phytoestrogens in cancers. Further research with carefully thought-through concepts and advanced methods on environmental estrogens will help to improve understanding for the identification of environmental influences, as well as provide novel mechanisms to guide the development of prevention and therapeutic approaches for human cancers.

Targeting cancer stem cells by nutraceuticals for cancer therapy

Accumulating evidence has demonstrated that cancer stem cells (CSCs) play an essential role in tumor progression and reoccurrence and drug resistance. Multiple signaling pathways have been revealed to be critically participated in CSC development and maintenance. Emerging evidence indicates that numerous chemopreventive compounds, also known as nutraceuticals, could eliminate CSCs in part via regulating several signaling pathways. Therefore, in this review, we will describe the some natural chemopreventive agents that target CSCs in a variety of human malignancies, including soy isoflavone, curcumin, resveratrol, tea polyphenols, sulforaphane, quercetin, indole-3-carbinol, 3,3'-diindolylmethane, withaferin A, apigenin, etc. Moreover, we discuss that eliminating CSCs by nutraceuticals might be a promising strategy for treating human cancer via overcoming drug resistance and reducing tumor reoccurrence.

5-Desmethylsinensetin isolated from Artemisia princeps suppresses the stemness of breast cancer cells via Stat3/IL-6 and Stat3/YAP1 signaling

AIMS

To study 5-desmethylsinensetin exhibiting potential anticancer activity against breast cancer stem cells and the related molecular mechanism.

MAIN METHODS

In this study, isolation of a cancer stem cell (CSC) inhibitor of Artemisia princeps was performed using a silica gel column, a Sephadex gel column, and high-performance liquid chromatography. A single compound was purified via activity-based isolation using mammosphere formation assays. An MTS was used to examine the proliferation of breast cancer cells, and flow cytometry was used to analyze apoptosis and cancer stem cell markers. Western blotting was used to detect the signaling pathway.

RESULTS

The isolated compound was identified as 5-desmethylsinensetin using nuclear magnetic resonance and mass spectrometry. 5-Desmethylsinensetin suppresses the proliferation and mammosphere formation of breast cancer cells, reduces the subpopulations of CD44⁺/CD24^- and ALDH1⁺ cancer cells, and reduces the transcription of the stemness markers Oct4, c-Myc, Nanog and CD44 in Breast CSCs. 5-Desmethylsinensetin inhibits the total and nuclear expression of Stat3 and p-Stat3, as well as the translocation of YAP1. Additionally, 5-desmethylsinensetin reduces the mRNA and protein levels of IL-6.

CONCLUSION

Our results show that 5-desmethylsinensetin exhibits potential anticancer activity against breast cancer stem cells via Stat3-IL-6 and Stat3-YAP1 signaling.

ETV4 promotes breast cancer cell stemness by activating glycolysis and CXCR4-mediated sonic Hedgehog signaling

Cancer stem cells (CSCs) are a major cause of tumor treatment resistance, relapse and metastasis. Cancer cells exhibit reprogrammed metabolism characterized by aerobic glycolysis, which is also critical for sustaining cancer stemness. However, regulation of cancer cell metabolism rewiring and stemness is not completely understood. Here, we report that ETV4 is a key transcription factor in regulating glycolytic gene expression. ETV4 loss significantly inhibits the expression of HK2, LDHA as well as other glycolytic enzymes, reduces glucose uptake and lactate release in breast cancer cells. In human breast cancer and hepatocellular carcinoma tissues, ETV4 expression is positively correlated with glycolytic signaling. Moreover, we confirm that breast CSCs (BCSCs) are glycolysis-dependent and show that ETV4 is required for BCSC maintenance. ETV4 is enriched in BCSCs, its knockdown and overexpression suppresses and promotes breast cancer cell stem-like traits, respectively. Mechanistically, on the one hand, we find that ETV4 may enhance glycolysis activity to facilitate breast cancer stemness; on the other, ETV4 activates Sonic Hedgehog signaling by transcriptionally promoting CXCR4 expression. A xenograft assay validates the tumor growth-impeding effect and inhibition of CXCR4/SHH/GLI1 signaling cascade after ETV4 depletion. Together, our study highlights the potential roles of ETV4 in promoting cancer cell glycolytic shift and BCSC maintenance and reveals the molecular basis.

Natural products targeting cancer stem cells: Implications for cancer chemoprevention and therapeutics

Cancer, being the leading cause of death in the globe, has been one of the major thrust areas of research worldwide. In a new paradigm about neoplastic transformations, the initiation and recurrence of disease is attributed to few mutated cells in bulk of tumor called cancer stem cells (CSCs). CSCs have capacity of self-renewal and differentiation, which are known for resistance to radio and chemotherapy leading to recurrence of the disease even after treatment. Most of traditional drugs implicated in cancer therapy targeting primary tumors have substantial toxicity to the physiological system and have not been efficient in targeting these CSCs leading to poor prognosis. Targeting these CSCs in bulk of tumor might be novel strategy for cancer chemoprevention and therapeutics. Diet-derived interventions and diverse natural products are known to target these CSCs and related signaling pathways, namely, Wnt, Notch, and Hedgehog pathways, which are implicated for CSC self-renewal. PRACTICAL APPLICATIONS: Cancer remains a global challenge even in this century. Poor prognosis, survival rate, and recurrence of the disease have been the major concerns in traditional cancer therapy regimes. Targeting cancer stem cells might be novel strategy for elimination and cure of the chronic disease as they are known to modulate all stages of carcinogenesis and responsible for recurrence and resistance to chemotherapy and radiotherapy. The evidence support that natural products might inhibit, delay, or reverse the process of tumorigenesis and modulate the different signaling pathways implicated for cancer stem cells self-renewal and differentiation. Natural products have minimal toxicity compared to traditional cancer therapy drugs since they have long been utilized in our food habits without any major side effects reported. Thus, targeting cancer stem cells with natural product might be a novel strategy for drug development in cancer chemoprevention and therapeutics.

Exosomes and Cancer Stem Cells in Cancer Immunity: Current Reports and Future Directions

Cancer stem cells (CSCs), which have the capacity to self-renew and differentiate into various types of cells, are notorious for their roles in tumor initiation, metastasis, and therapy resistance. Thus, underlying mechanisms for their survival provide key insights into developing effective therapeutic strategies. A more recent focus has been on exosomes that play a role in transmitting information between CSCs and non-CSCs, resulting in activating CSCs for cancer progression and modulating their surrounding microenvironment. The field of CSC-derived exosomes (CSCEXs) for different types of cancer is still under exploration. A deeper understanding and further investigation into CSCEXs’ roles in tumorigenicity and the identification of novel exosomal components are necessary for engineering exosomes for the treatment of cancer. Here, we review the features of CSCEXs, including surface markers, cargo, and biological or physiological functions. Further, reports on the immunomodulatory effects of CSCEXs are summarized, and exosome engineering for CSC-targeting is also discussed.

Pterostilbene alleviates cerebral ischemia and reperfusion injury in rats by modulating microglial activation

Ischemic stroke is a severe neurological disease without known effective therapy. Microglia-mediated neuroinflammation plays an important role in ischemic stroke. Therefore, finding a safe and effective microglial activation inhibitor might lead to an effective therapeutic strategy against ischemic stroke. In this project, our goal was to explore both the mechanism and effect of pterostilbene in MCAO/R rats. The potential effect of pterostilbene on ischemic stroke was tested using MCAO/R rats and its effect on microglial activation was tested in LPS-stimulated BV-2 cells. In vivo, pterostilbene decreased the neurological scores, brain water content and infarct volume in MCAO/R rats. Pterostilbene increased the number of mature neurons, decreased the number of activated microglia, and reduced iNOS and IL-1β mRNA expression. Pterostilbene inhibited phosphorylated-IκBα expression, thus promoting IκBα expression and inhibiting ROS overexpression. In vitro, pterostilbene inhibited the expression of inflammatory cytokines and suppressed NAPDH activity as well as activation of both the NF-κB pathway and ROS production. To our knowledge, our study is the first to demonstrate that pterostilbene-mediated alleviation of cerebral ischemia and reperfusion injury in rats may be correlated with the inhibition of the ROS/NF-κB-mediated inflammatory pathway in microglia, indicating the potential for the use of pterostilbene as a candidate therapeutic compound for ischemic stroke.

Reprogramming Cancer Stem-like Cells with Nanoforskolin Enhances the Efficacy of Paclitaxel in Targeting Breast Cancer

Cancer stem-like cells (CSCs) have emerged as an important target for breast cancer therapy owing to their self-renewability, proliferation, and elevated chemoresistance properties. Here, we present a strategy of eliminating CSCs by differentiation therapy where "forced differentiation" reprograms CSCs so that they lose their intrinsic properties and become susceptible for conventional chemotherapeutic drugs. In this study, we report that a conventional chemotherapeutic paclitaxel enhances the stemness of CSCs, while a phytochemical forskolin being essentially nontoxic to CSCs possesses the intrinsic ability to reprogram them. To achieve simultaneous targeting of CSCs and bulk tumor cells, we used a co-delivery system where liquid crystal nanoparticles (LCN) were co-encapsulated with both paclitaxel and forskolin. LCN showed higher uptake, retention, and penetration potential in CSCs overcoming their high drug efflux property. Moreover, LCN improved the pharmacokinetic parameters of forskolin, which otherwise had very low retention and bioavailability. Forskolin-loaded LCN forced CSCs to exit from their mesenchymal state, which reduced their stemness and chemosensitized them while inhibiting E-cadherin-mediated survival and tumor-initiating potential as well as reversing paclitaxel-induced stemness. We further showed that upon administration of paclitaxel and forskolin co-loaded LCN to an orthotropic xenograft mouse model, the nanomedicine showed enhanced passive tumor targeting capability with very potent antitumor activity that eradicated small solid tumor in a single dose and showed no sign of tumor relapse or systemic toxicity over a long period. Overall, these findings give a proof of concept that co-delivery of forskolin and paclitaxel in a single nanoformulation can achieve overall tumor targeting where forskolin can efficiently reprogram/differentiate CSCs and paclitaxel can induce cytotoxicity in both differentiated CSCs and bulk tumor cells simultaneously. Hence, this study can provide a nanoformulation that can offer an efficient strategy for cancer therapy.

Capsaicin on stem cell proliferation and fate determination - a novel perspective

Capsaicin (CAP), a member of the vanilloid family, is the main active component of chili peppers, which has been widely explored for its various pharmacological effects and influence on cell physiology, such as axonal growth and apoptosis of tumor cells. In particular, CAP plays a crucial role in determining the proliferation and fate specification of stem cells by modulating a variety of signaling pathways, such as PPARγ, C/EBPα and Notch signaling. Since CAP-mediated processes are complex and multifactorial, we hope to achieve a better understanding of these processes and their implications in clinical applications. This review aims to shed light on the influences and mechanisms of CAP on the actions of various stem cells in adults and discusses the role of CAP in the different process of stem cell behaviors, including proliferation and differentiation. Our purpose is to provide certain prospects for the application of CAP and stem cell therapy in treating diseases.

Novel molecular regulators of breast cancer stem cell plasticity and heterogeneity

Tumors consist of heterogeneous cell populations, and tumor heterogeneity plays key roles in regulating tumorigenesis, metastasis, recurrence and resistance to anti-tumor therapies. More and more studies suggest that cancer stem cells (CSCs) promote tumorigenesis, metastasis, recurrence and drug resistance as well as are the major source for heterogeneity of cancer cells. CD24^-CD44⁺ and ALDH⁺ are the most common markers for breast cancer stem cells (BCSCs). Previous studies showed that different BCSC markers label different BCSC populations, indicating the heterogeneity of BCSCs. Therefore, defining the regulation mechanisms of heterogeneous BCSCs is essential for precisely targeting BCSCs and treating breast cancer. In this review, we summarized the novel regulators existed in BCSCs and their niches for BCSC heterogeneity which has been discovered in recent years, and discussed their regulation mechanisms and the latest corresponding cancer treatments, which will extend our understanding on BCSC heterogeneity and plasticity, and provide better prognosis prediction and more efficient novel therapeutic strategies for breast cancer.

Dietary Phytochemicals as a Potential Source for Targeting Cancer Stem Cells

The tumor microenvironment is composed of various types of cells that lead to tumor heterogeneity. In the middle of these populations, cancer stem cells play a vital role in the initiation and progression of cancer cells and are capable of self-renewal and differentiation processes. These cancer stem cells are resistant to conventional therapy such as chemotherapy and radiotherapy. To eradicate the cancer stem cells in the tumor environment, various natural product has been found in recent years. In this review, we have selected some of the natural products based on anticancer potential including targeting cancer cells and cancer stem cells. Further, this review explains the molecular mechanism of action of these natural products in various cancer stem cells. Therefore, targeting a multi-drug resistant cancer stem cell by natural products is a novel method to reduce drug resistance and adverse effect during conventional therapy.

Epigenetic targeting of cancer stem cells by polyphenols (cancer stem cells targeting)

Epigenetic alterations are one of the main factors that disrupt the expression of genes and consequently, they have an important role in the carcinogenicity and the progression of different cancers. Cancer stem cells (CSCs) are accountable for the recurrence, metastasis, and therapeutic failure of cancer. The noticeable and specific pathways in CSCs can be organized by epigenetic mechanisms such as DNA methylation, chromatin remodeling, regulatory RNAs, among others. Since epigenetics modifications can be changed and reversed, it is a possible tool for cancer control and treatment. Epigenetic therapies against CSCs are emerging as a very new strategy with a good future expectation to treat cancer patients. Phenolic compounds are a vast group of substances with anticarcinogenic functions, antiinflammatory, and antioxidative activities. It seems these characteristics are related to neutralizing CSCs development, their microenvironment, and metabolism through epigenetic mechanisms. In the current work, the types of epigenetic changes known in these cells are introduced. In addition, some studies about the use of polyphenols acting through a variety of epigenetic mechanisms to counteract these cells will be reviewed. The reported results seem to indicate that the use of these phenolic compounds may be useful for CSCs defeat.

Hopea odorata Extract Can Efficiently Kill Breast Cancer Cells and Cancer Stem-Like Cells in Three-Dimensional Culture More Than in Monolayer Cell Culture

INTRODUCTION

The breast cancer cells with CD44⁺CD24^- phenotype are known to play an important role in tumorigenesis, drug resistance, and cancer recurrence. Breast cancer cells with CD44⁺CD24^- phenotype are cultured in three-dimensional (3D) stereotype showing the recapitulation of tumors in vivo such as cell differentiation, heterogeneity, and microenvironment. Using this 3D model in anti-cancer compound research results in a more accurate reflection than conventional monolayer cell culture. This study aimed to identify the antitumor activity of Hopea odorata methanol extract (HO-MeOH-E) on breast cancer cells and cancer stem-like cells in both models of three-dimensional culture (3D) and monolayer cell culture (2D).

METHODS

HO-MeOH-E was produced from Hopea odorata plant. The VN9 breast cancer cells (VN9) were collected and expanded from the previous study. The breast cancer stem-like cells (VN9CSC) were sorted from the VN9 based on phenotype CD44⁺CD24^-. Both VN9 and VN9CSC were used to culture in monolayer culture (2D) and organoids (3D) before they were used to treat with HO-MeOH-E. Two other anticancer drugs, doxorubicin and tirapazamine, were used as references. The antitumor activities of extracts and drugs were determined via two assays: antiproliferation using the Alamar blue assay and cell cycle assay.

RESULTS

The results showed that HO-MeOH-E was sensitive to both VN9 and VN9CSC in 3D more than 2D culture (IC₅₀ on 3D organoids 144.8 ± 2.172 μg/mL and on 2D 340.2 ± 17.01 μg/mL for VN9CSC (p < 0.001); IC₅₀ on 3D organoids 2055 ± 82.2 μg/mL and on 2D 430.6 ± 8.612 μg/mL for VN9 (p < 0.0001), respectively). HO-MeOH-E inhibits VN9CSC proliferation by blocking S phase and increasing the populations of apoptotic cells; this is consensus to the effect of tirapazamine (TPZ) which is used in hypoxia-activated chemotherapy.

CONCLUSION

Taken these results, HO-MeOH-E has the potential effect in hypoxia-activated chemotherapy specifically on breast cancer stem-like cells with CD44⁺CD24^- phenotype.