Cancer stem cells and metastasis. Semin Cancer Biol. 2012;22:187-193. [PMID: 22774232 DOI: 10.1016/j.semcancer.2012.03.002]

Lipopolysaccharide Induces Resistance to CAR-T Cell Therapy of Colorectal Cancer Cells through TGF-β-Mediated Stemness Enhancement

Chimeric antigen receptor-T (CAR-T) cell therapy is a cellular immunotherapy that has emerged in recent years, and increasing studies showed that therapeutic resistance to CAR-T cell therapy presents in colorectal cancer patients. Lipopolysaccharide (LPS), a component of the cell wall of Gram-negative bacteria, is known to preserve a high concentration in the colon. Whether LPS is a contributing factor to the development of resistance in colorectal cancer cells against CAR-T cell therapy remains unclear. For in vivo experiments, colorectal cancer cells COLO205 were pretreated with LPS for 24 h and then were injected into nude mice through the tail vein, followed by CAR-T cells transplantation one day later. Later, the number of tumors in the lung tissues of the mice was observed. The in vitro experiments were performed on COLO205 cells, which were treated with LPS for 24 h. The effect of LPS on the stemness of COLO205 and SW620 cells was observed by using the colony formation assay and spheroidization experiments. The effect of LPS on the expression of stemness-related genes, including CD44, SOX2, and NANOG, was observed by qRT-PCR assay, Western blotting assay, and immunofluorescence staining. Inhibitors of TGF-β and the MYD88 inhibitor were used to study the mechanisms by which LPS induces the stemness enhancement and resistance to CAR-T cell therapy of COLO205 cells. The correlation between MYD88 and TGFB1, as well as the correlation between TGFB1 and stemness-related genes was analyzed using the TCGA database. Both the in vivo assay of nude mice and the in vitro assay showed that LPS pretreatment could induce resistance to CAR-T cell therapy of colorectal cancer cells. LPS could enhance COLO205 and SW620 cells stemness presented by upregulation of CD44, SOX2, and NANOG. The reverse interfering assay using the TGF-β inhibitor indicated that the autosecretion of TGF-β induced by LPS played a critical role in the stemness enhancement of colorectal cancer cells. The TCGA database analysis revealed a strong positive correlation between MYD88 and TGFB1. Additionally, TGFB1 has been found to upregulate the expression of genes associated with stemness. Further mechanism studies showed that the TLR4/MYD88 pathway medicates LPS-induced TGF-β expression. Our results suggested that LPS-induced resistance to CAR-T cell therapy of colorectal cancer cells through stemness enhancement. TLR4/MYD88 signal pathway-dependent TGF-β expression was involved in stemness enhancement and CAR-T cell therapy resistance. In conclusion, our findings help us to understand the underlying mechanisms of CAR-T cell therapy resistance and indicate that inhibitors of TGF-β and MYD88 are promising targeting candidates to promote a therapeutic effect of CAR-T cell therapy in colorectal cancer in the clinic.

A prognostic nomogram for distant metastasis in thyroid cancer patients without lymph node metastasis

Background

Despite having negative lymph node (N0) status, thyroid cancer (TC) patients can still experience distant metastasis (DM), which significantly impacts their survival. This study aimed to investigate the prognostic factors for DM in TC patients (N0) and develop a predictive nomogram model for analyzing the prognosis of TC N0 patients with DM.

Methods

Data collected from the Surveillance, Epidemiology, and End Results (SEER) database for 18,504 TC patients (N0) between 2004 and 2015 were analyzed. Univariate and multivariate analyses were used to identify independent prognostic factors for DM in TC N0. These independent factors were used to build a nomogram model to predict overall survival (OS) at 1, 3, and 5 years for TC patients (N0) with DM.

Results and conclusion

This study examined the clinicopathological features associated with the risk and prognosis of DM in TC patients (N0), and successfully established and validated a nomogram capable of predicting OS in individual patients with DM. The nomogram is highly useful for the timely identification of TC patients (N0) at high risk of DM by physicians, enabling individualized survival evaluations and treatment for TC patients with DM (N0).

EpCAM Signaling in Oral Cancer Stem Cells: Implications for Metastasis, Tumorigenicity, and Therapeutic Strategies

Oral cancer, a subtype of head and neck cancer, poses significant global health challenges owing to its late diagnosis and high metastatic potential. The epithelial cell adhesion molecule (EpCAM), a transmembrane glycoprotein, has emerged as a critical player in cancer biology, particularly in oral cancer stem cells (CSCs). This review highlights the multifaceted roles of EPCAM in regulating oral cancer metastasis, tumorigenicity, and resistance to therapy. EpCAM influences key pathways, including Wnt/β-catenin and EGFR, modulating CSC self-renewal, epithelial-to-mesenchymal transition (EMT), and immune evasion. Moreover, EpCAM has been implicated in metabolic reprogramming, epigenetic regulation, and crosstalk with other signaling pathways. Advances in EpCAM-targeting strategies, such as monoclonal antibodies, chimeric antigen receptor (CAR) T/NK cell therapies, and aptamer-based systems hold promise for personalized cancer therapies. However, challenges remain in understanding the precise mechanism of EpCAM in CSC biology and its translation into clinical applications. This review highlights the need for further investigation into the role of EPCAM in oral CSCs and its potential as a therapeutic target to improve patient outcomes.

Inhibition of TFF3 synergizes with c-MET inhibitors to decrease the CSC-like phenotype and metastatic burden in ER+HER2+ mammary carcinoma

The interaction between HER2 and ERα signaling pathways contributes to resistance to anti-estrogen and HER2-targeted therapies, presenting substantial treatment challenges in ER-positive (ER+) HER2-positive (HER2+) mammary carcinoma (MC). Trefoil Factor-3 (TFF3) has been reported to mediate resistance to both anti-estrogen and anti-HER2 targeted therapies in ER+ and ER+HER2+ MC, respectively. Herein, the function and mechanism of TFF3 in ER+HER2+ MC were delineated; and novel combinatorial therapeutic strategies were identified. Elevated expression of TFF3 promoted the oncogenicity of ER+HER2+ MC cells, including enhanced cell proliferation, survival, anchorage-independent growth, 3D growth, cancer stem cell-like (CSC-like) phenotype, migration, invasion, and xenograft growth. Targeting TFF3 with an interfering RNA plasmid or a small-molecule inhibitor (AMPC) inhibited these oncogenic characteristics, highlighting the therapeutic potential of targeting TFF3 in ER+HER2+ MC. Furthermore, a high-throughput combinatorial anti-cancer compound library screening revealed that AMPC preferentially synergized with receptor tyrosine kinase c-MET inhibitors (c-METis) to reduce cell survival and the CSC-like phenotype. The combination of AMPC and c-METis also synergistically suppressed the in vivo growth of ER+HER2+ MC cell-derived xenografts and abrogated lung metastasis. Mechanistically, TFF3 was observed to activate c-MET signaling through a positive-feedback loop to enhance the CSC-like phenotype of ER+HER2+ MC. Therefore, proof of concept is provided herein that antagonizing of TFF3 is a promising therapeutic strategy in combination with c-MET inhibition for the treatment of ER+HER2+ MC.

The role of CD95 in modulating CAR T-cell therapy: Challenges and therapeutic opportunities in oncology

CAR T cell therapy has revolutionized how we deliver cancer treatment, most notably for hematologic cancers, by compelling T cells to recognize and kill tumor cells. Nevertheless, current obstacles to utilizing this therapy in solid tumors and overcoming cancer resistance include radicalization. This review discusses how CD95 modulation can boost CAR T cell efficacy. Traditionally, CD95 was known to execute apoptosis induction, but it plays a dual role in induced cell death or in supporting cancer cell survival. Recent data have demonstrated that cancer cells escape CD95-mediated apoptosis via the downregulation of CD95, caspase 8 mutation, or the expression of the inhibition protein cFLIP. Additionally, the immunosuppressive tumor microenvironment, containing CD95L expressing immune cells, explains CAR T cell therapy resistance. Furthermore, we characterize the therapeutic potential of CD95 targeted approaches, including CD95L inhibition (APG101) and alterations in CAR T cell manufacturing (tyrosine kinase inhibitors to mitigate fratricide). In this review, we highlight the importance of multi-path way strategies combining CD95 modulation with CAR T cell engineering to overcome resistance, specifically to target tumor cells better and sustain CAR T cell persistence to enhance treatment efficacy in solid tumors.

Self-assembled aldehyde dehydrogenase-activatable nano-prodrug for cancer stem cell-enriched tumor detection and treatment

Cancer stem cells, characterized by high tumorigenicity and drug-resistance, are often responsible for tumor progression and metastasis. Aldehyde dehydrogenases, often overexpressed in cancer stem cells enriched tumors, present a potential target for specific anti-cancer stem cells treatment. In this study, we report a self-assembled nano-prodrug composed of aldehyde dehydrogenases activatable photosensitizer and disulfide-linked all-trans retinoic acid for diagnosis and targeted treatment of cancer stem cells enriched tumors. The disulfide-linked all-trans retinoic acid can load with photosensitizer and self-assemble into a stable nano-prodrug, which can be disassembled into all-trans retinoic acid and photosensitizer in cancer stem cells by high level of glutathione. As for the released photosensitizer, overexpressed aldehyde dehydrogenase catalyzes the oxidation of aldehydes to carboxyl under cancer stem cells enriched microenvironment, activating the generation of reactive oxygen species and fluorescence emission. This generation of reactive oxygen species leads to direct killing of cancer stem cells and is accompanied by a noticeable fluorescence enhancement for real-time monitoring of the cancer stem cells enriched microenvironment. Moreover, the released all-trans retinoic acid, as a differentiation agent, reduce the cancer stem cells stemness and improve the cancer stem cells enriched microenvironment, offering a synergistic effect for enhanced anti-cancer stem cells treatment of photosensitizer in inhibition of in vivo tumor growth and metastasis.

ALDH1A3 is the switch that determines the balance of ALDH+ and CD24-CD44+ cancer stem cells, EMT-MET, and glucose metabolism in breast cancer

Plasticity is an inherent feature of cancer stem cells (CSCs) and regulates the balance of key processes required at different stages of breast cancer progression, including epithelial-to-mesenchymal transition (EMT) versus mesenchymal-to-epithelial transition (MET), and glycolysis versus oxidative phosphorylation. Understanding the key factors that regulate the switch between these processes could lead to novel therapeutic strategies that limit tumor progression. We found that aldehyde dehydrogenase 1A3 (ALDH1A3) regulates these cancer-promoting processes and the abundance of the two distinct breast CSC populations defined by high ALDH activity and CD24-CD44+ cell surface expression. While ALDH1A3 increases ALDH+ breast cancer cells, it inversely suppresses the CD24-CD44+ population by retinoic acid signaling-mediated gene expression changes. This switch in CSC populations induced by ALDH1A3 was paired with decreased migration but increased invasion and an intermediate EMT phenotype. We also demonstrate that ALDH1A3 increases oxidative phosphorylation and decreases glycolysis and reactive oxygen species (ROS). The effects of ALDH1A3 reduction were countered with the glycolysis inhibitor 2-deoxy-D-glucose (2DG). In cell culture and tumor xenograft models, 2DG suppresses the increase in the CD24-CD44+ population and ROS induced by ALDH1A3 knockdown. Combined inhibition of ALDH1A3 and glycolysis best reduces breast tumor growth and tumor-initiating cells, suggesting that the combination of targeting ALDH1A3 and glycolysis has therapeutic potential for limiting CSCs and tumor progression. Together, these findings identify ALDH1A3 as a key regulator of processes required for breast cancer progression and depletion of ALDH1A3 makes breast cancer cells more susceptible to glycolysis inhibition.

Microfluidic Applications in Prostate Cancer Research

Prostate cancer is a disease in which cells in the prostate, a gland in the male reproductive system below the bladder, grow out of control and, among men, it is the second-most frequently diagnosed cancer (other than skin cancer). In recent years, prostate cancer death rate has stabilized and, currently, it is the second-most frequent cause of cancer death in men (after lung cancer). Most deaths occur due to metastasis, as cancer cells from the original tumor establish secondary tumors in distant organs. For a long time, classical cell cultures and animal models have been utilized in basic and applied scientific research, including clinical applications for many diseases, such as prostate cancer, since no better alternatives were available. Although helpful in dissecting cellular mechanisms, these models are poor predictors of physiological behavior mainly because of the lack of appropriate microenvironments. Microfluidics has emerged in the last two decades as a technology that could lead to a paradigm shift in life sciences and, in particular, controlling cancer. Microfluidic systems, such as organ-on-chips, have been assembled to mimic the critical functions of human organs. These microphysiological systems enable the long-term maintenance of cellular co-cultures in vitro to reconstitute in vivo tissue-level microenvironments, bridging the gap between traditional cell cultures and animal models. Several reviews on microfluidics for prostate cancer studies have been published focusing on technology advancement and disease progression. As metastatic castration-resistant prostate cancer remains a clinically challenging late-stage cancer, with no curative treatments, we expanded this review to cover recent microfluidic applications related to prostate cancer research. The review includes discussions of the roles of microfluidics in modeling the human prostate, prostate cancer initiation and development, as well as prostate cancer detection and therapy, highlighting potentially major contributions of microfluidics in the continuous march toward eradicating prostate cancer.

Concomitant Delivery of Pirarubicin and Salinomycin Synergistically Enhanced the Efficacy of Cancer Therapy and Reduced the Risk of Cancer Relapse

Pirarubicin attracted considerable attention in clinical studies because of its high therapeutic efficacy and reduced toxicity in comparison with other anthracyclines. Nevertheless, ~ 30% patients undergoing PIRA treatment still experience relapse and metastasis. Clinical advancements unveiled that cancer stem cells (CSCs) residing in the tumor constitutes a major factor for such limitations and subsequently are the reason for treatment failure. Consequently, eradicating CSCs alongside bulk tumor is a crucial undertaking to attain utmost therapeutic efficacy of the treatment. Nevertheless, majority of the CSCs inhibitors currently under examination lack specificity, show unsynchronized bioavailability with other primary treatments and exhibit notable toxicity in their therapeutic applications, which is primarily attributable to their inadequate tumor-targeting capabilities. Therefore, we have developed a biodegradable polylactic acid based blend block copolymeric NPs for concomitant delivery of CSCs inhibitor Salinomycin (SAL) & chemotherapeutic drug Pirarubicin (PIRA) with an aim to improve the efficacy of treatment and prevent cancer relapse. Prepared NPs showed < 100 nm size and excellent loading with sustained release for both the drugs. Also, PIRA:SAL co-loaded NPs exhibits synergistically enhanced cytotoxicity against cancer cell as well as CSCs. Most importantly, NPs mediated co-delivery of the drugs showed complete tumor eradication, without any reoccurrence throughout the surveillance period. Additionally, NPs treatment didn't show any histopathological alteration in vital organs confirming their non-toxic nature. Altogether, present study concludes that the developed PIRA:SAL NPs have excellent efficacy for tumor regression as well as prevention of cancer relapse, hence can be used as a potential combination therapy for cancer treatment.

UM171 suppresses breast cancer progression by inducing KLF2

PURPOSE

Breast cancer is the most frequent cancer in women with significant death rate. Morbidity is associated with drug resistance and metastasis. Development of novel drugs is unmet need. The aim of this study is to show potent anti-neoplastic activity of the UM171 compound on breast cancer cells and its mechanism of action.

METHODS

The inhibitory effect of UM171 on several breast cancer (BC) cell lines was examined using MTT and colony-forming assays. Cell cycle and apoptosis assays were utilized to determine the effect of UM171 on BC cell proliferation and survival. Wound healing scratch and transwell migration assays were used to examine the migration of BC cell lines in culture. Xenograft of mouse model with 4T1 cells was used to determine inhibitory effect of UM171 in vivo. Q-RT-PCR and western blotting were used to determine the expression level of genes effected by UM171. Lentivirus-mediated shRNAs were used to knockdown the expression of KLF2 in BC cells.

RESULTS

UM171 was previously identified as a potent agonist of human hematopoietic stem cell renewal and inhibitor of leukemia. In this study, UM171 was shown to inhibit the growth of multiple breast cancer cell lines in culture. UM171-mediated growth inhibition was associated with the induction of apoptosis, G2/M cell cycle arrest, lower colony-forming capacity, and reduced motility. In a xenotransplantation model of mouse triple-negative breast cancer 4T1 cells injected into syngeneic BALB/c mice, UM171 strongly inhibited tumor growth at a level comparable to control paclitaxel. UM171 increased the expression of the three PIM genes (PIM1-3) in breast cancer cells. Moreover, UM171 strongly induced the expression of the tumor suppressor gene KLF2 and cell cycle inhibitor P21CIP1. Accordingly, knockdown of KLF2 using lentivirus-mediated shRNA significantly attenuated the growth suppressor activity of UM171. As PIM1-3 act as oncogenes and are involved in breast cancer progression, induction of these kinases likely impedes the inhibitory effect of KLF2 induction by UM171. Accordingly, combination of UM171 with a PAN-PIM inhibitor LGH447 significantly reduced tumor growth in culture.

CONCLUSION

These results suggested that UM171 inhibited breast cancer progression in part through activation of KLF2 and P21. Combination of UM171 with a PAN-PIM inhibitor offer a novel therapy for aggressive forms of breast cancer.

Extracellular vesicles and cancer stem cells: a deadly duo in tumor progression

The global incidence of cancer is increasing, with estimates suggesting that there will be 26 million new cases and 17 million deaths per year by 2030. Cancer stem cells (CSCs) and extracellular vesicles (EVs) are key to the resistance and advancement of cancer. They play a crucial role in tumor dynamics and resistance to therapy. CSCs, initially discovered in acute myeloid leukemia, are well-known for their involvement in tumor initiation, progression, and relapse, mostly because of their distinct characteristics, such as resistance to drugs and the ability to self-renew. EVs, which include exosomes, microvesicles, and apoptotic bodies, play a vital role in facilitating communication between cells within the tumor microenvironment (TME). They have a significant impact on cellular behaviors and contribute to genetic and epigenetic changes. This paper analyzes the mutually beneficial association between CSCs and EVs, emphasizing their role in promoting tumor spread and developing resistance mechanisms. This review aims to investigate the interaction between these entities in order to discover new approaches for attacking the complex machinery of cancer cells. It highlights the significance of CSCs and EVs as crucial targets in the advancement of novel cancer treatments, which helps stimulate additional research, promote progress in ideas for cancer treatment, and provide renewed optimism in the effort to reduce the burden of cancer.

Exploring Importance and Regulation of Autophagy in Cancer Stem Cells and Stem Cell-Based Therapies

Autophagy is a globally conserved cellular activity that plays a critical role in maintaining cellular homeostasis through the breakdown and recycling of cellular constituents. In recent years, there has been much emphasis given to its complex role in cancer stem cells (CSCs) and stem cell treatment. This study examines the molecular processes that support autophagy and how it is regulated in the context of CSCs and stem cell treatment. Although autophagy plays a dual role in the management of CSCs, affecting their removal as well as their maintenance, the intricate interaction between the several signaling channels that control cellular survival and death as part of the molecular mechanism of autophagy has not been well elucidated. Given that CSCs have a role in the development, progression, and resistance to treatment of tumors, it is imperative to comprehend their biological activities. CSCs are important for cancer biology because they also show a tissue regeneration model that helps with organoid regeneration. In other words, the manipulation of autophagy is a viable therapeutic approach in the treatment of cancer and stem cell therapy. Both synthetic and natural substances that target autophagy pathways have demonstrated promise in improving stem cell-based therapies and eliminating CSCs. Nevertheless, there are difficulties associated with the limitations of autophagy in CSC regulation, including resistance mechanisms and off-target effects. Thus, the regulation of autophagy offers a versatile strategy for focusing on CSCs and enhancing the results of stem cell therapy. Therefore, understanding the complex interactions between autophagy and CSC biology would be essential for creating therapeutic treatments that work in both regenerative medicine and cancer treatment.

A novel glycolysis-related gene signature for predicting the prognosis of multiple myeloma

Background: Metabolic reprogramming is an important hallmark of cancer. Glycolysis provides the conditions on which multiple myeloma (MM) thrives. Due to MM's great heterogeneity and incurability, risk assessment and treatment choices are still difficult. Method: We constructed a glycolysis-related prognostic model by Least absolute shrinkage and selection operator (LASSO) Cox regression analysis. It was validated in two independent external cohorts, cell lines, and our clinical specimens. The model was also explored for its biological properties, immune microenvironment, and therapeutic response including immunotherapy. Finally, multiple metrics were combined to construct a nomogram to assist in personalized prediction of survival outcomes. Results: A wide range of variants and heterogeneous expression profiles of glycolysis-related genes were observed in MM. The prognostic model behaved well in differentiating between populations with various prognoses and proved to be an independent prognostic factor. This prognostic signature closely coordinated with multiple malignant features such as high-risk clinical features, immune dysfunction, stem cell-like features, cancer-related pathways, which was associated with the survival outcomes of MM. In terms of treatment, the high-risk group showed resistance to conventional drugs such as bortezomib, doxorubicin and immunotherapy. The joint scores generated by the nomogram showed higher clinical benefit than other clinical indicators. The in vitro experiments with cell lines and clinical subjects further provided convincing evidence for our study. Conclusion: We developed and validated the utility of the MM glycolysis-related prognostic model, which provides a new direction for prognosis assessment, treatment options for MM patients.

Inhibitory Potential of Resveratrol in Cancer Metastasis: From Biology to Therapy

Cancer metastasis is a significant challenge in cancer treatment, and most existing drugs are designed to inhibit tumor growth but are often ineffective in treating metastatic cancer, which is the leading cause of cancer-related deaths. Resveratrol, a polyphenol found in grapes, berries, and peanuts, has shown potential in preclinical studies as an anticancer agent to suppress metastasis. However, despite positive results in preclinical studies, little progress has been made in clinical trials. To develop resveratrol as an effective anticancer agent, it is crucial to understand its cellular processes and signaling pathways in tumor metastasis. This review article evaluates the current state and future development strategies of resveratrol to enhance its potency against cancer metastasis within its therapeutic dose. In addition, we critically evaluate the animal models used in preclinical studies for cancer metastasis and discuss novel techniques to accelerate the translation of resveratrol from bench to bedside. The appropriate selection of animal models is vital in determining whether resveratrol can be further developed as an antimetastatic drug in cancer therapy.

Cancer stem cells: an insight into the development of metastatic tumors and therapy resistance

The term "cancer stem cells" (CSCs) refers to cancer cells that exhibit traits parallel to normal stem cells, namely the potential to give rise to every type of cell identified in a tumor microenvironment. It has been found that CSCs usually develops from other neoplastic cells or non-cancerous somatic cells by acquiring stemness and malignant characteristics through particular genetic modifications. A trivial number of CSCs, identified in solid and liquid cancer, can give rise to an entire tumor population with aggressive anticancer drug resistance, metastasis, and invasiveness. Besides, cancer stem cells manipulate their intrinsic and extrinsic features, regulate the metabolic pattern of the cell, adjust efflux-influx efficiency, modulate different signaling pathways, block apoptotic signals, and cause genetic and epigenetic alterations to retain their pluripotency and ability of self-renewal. Notably, to keep the cancer stem cells' ability to become malignant cells, mesenchymal stem cells, tumor-associated fibroblasts, immune cells, etc., interact with one another. Furthermore, CSCs are characterized by the expression of particular molecular markers that carry significant diagnostic and prognostic significance. Because of this, scientific research on CSCs is becoming increasingly imperative, intending to understand the traits and behavior of cancer stem cells and create more potent anticancer therapeutics to fight cancer at the CSC level. In this review, we aimed to elucidate the critical role of CSCs in the onset and spread of cancer and the characteristics of CSCs that promote severe resistance to targeted therapy.

Carbon nanomaterial-involved EMT and CSC in cancer

Carbon nanomaterials (CNMs) are ubiquitous in our daily lives because of the outstanding physicochemical properties. CNMs play curial parts in industrial and medical fields, however, the risks of CNMs exposure to human health are still not fully understood. In view of, it is becoming extremely difficult to ignore the existence of the toxicity of CNMs. With the increasing exploitation of CNMs, it's necessary to evaluate the potential impact of these materials on human health. In recent years, more and more researches have shown that CNMs are contributed to the cancer formation and metastasis after long-term exposure through epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) which is associated with cancer progression and invasion. This review discusses CNMs properties and applications in industrial and medical fields, adverse effects on human health, especially the induction of tumor initiation and metastasis through EMT and CSCs procedure.

Exploiting the Stemness and Chemoresistance Transcriptome of Ewing Sarcoma to Identify Candidate Therapeutic Targets and Drug-Repurposing Candidates

Outcomes for most patients with Ewing sarcoma (ES) have remained unchanged for the last 30 years, emphasising the need for more effective and tolerable treatments. We have hypothesised that using small-molecule inhibitors to kill the self-renewing chemotherapy-resistant cells (Ewing sarcoma cancer stem-like cells; ES-CSCs) responsible for progression and relapse could improve outcomes and minimise treatment-induced morbidities. For the first time, we demonstrate that ABCG1, a potential oncogene in some cancers, is highly expressed in ES-CSCs independently of CD133. Using functional models, transcriptomics and a bespoke in silico drug-repurposing pipeline, we have prioritised a group of tractable small-molecule inhibitors for further preclinical studies. Consistent with the cellular origin of ES, 21 candidate molecular targets of pluripotency, stemness and chemoresistance were identified. Small-molecule inhibitors to 13 of the 21 molecular targets (62%) were identified. POU5F1/OCT4 was the most promising new therapeutic target in Ewing sarcoma, interacting with 10 of the 21 prioritised molecular targets and meriting further study. The majority of small-molecule inhibitors (72%) target one of two drug efflux proteins, p-glycoprotein (n = 168) or MRP1 (n = 13). In summary, we have identified a novel cell surface marker of ES-CSCs and cancer/non-cancer drugs to targets expressed by these cells that are worthy of further preclinical evaluation. If effective in preclinical models, these drugs and drug combinations might be repurposed for clinical evaluation in patients with ES.

Cancer Stem Cells: Biology and Therapeutic Implications

It is well recognized that most cancers derive and progress from transformation and clonal expansion of a single cell that possesses stem cell properties, i.e., self-renewal and multilineage differentiation capacities. Such cancer stem cells (CSCs) are usually present at very low frequencies and possess properties that make them key players in tumor development. Indeed, besides having the ability to initiate tumor growth, CSCs drive tumor progression and metastatic dissemination, are resistant to most cancer drugs, and are responsible for cancer relapse. All of these features make CSCs attractive targets for the development of more effective oncologic treatments. In the present review article, we have summarized recent advances in the biology of CSCs, including their identification through their immunophenotype, and their physiology, both in vivo and in vitro. We have also analyzed some molecular markers that might become targets for developing new therapies aiming at hampering CSCs regeneration and cancer relapse.

Harnessing NK Cells to Control Metastasis

In recent years, tumor immunotherapy has produced remarkable results in tumor treatment. Nevertheless, its effects are severely limited in patients with low or absent pre-existing T cell immunity. Accordingly, metastasis remains the major cause of tumor-associated death. On the other hand, natural killer (NK) cells have the unique ability to recognize and rapidly act against tumor cells and surveil tumor cell dissemination. The role of NK cells in metastasis prevention is undisputable as an increase in the number of these cells mostly leads to a favorable prognosis. Hence, it is reasonable to consider that successful metastasis involves evasion of NK-cell-mediated immunosurveillance. Therefore, harnessing NK cells to control metastasis is promising. Circulating tumor cells (CTCs) are the seeds for distant metastasis, and the number of CTCs detected in the blood of patients with tumor is associated with a worse prognosis, whereas NK cells can eliminate highly motile CTCs especially in the blood. Here, we review the role of NK cells during metastasis, particularly the specific interactions of NK cells with CTCs, which may provide essential clues on how to harness the power of NK cells against tumor metastasis. As a result, a new way to prevent or treat metastatic tumor may be developed.

Role of O-GlcNAcylation on cancer stem cells: Connecting nutrient sensing to cell plasticity

Tumor growth and metastasis can be promoted by a small sub-population of cancer cells, termed cancer stem-like cells (CSCs). While CSCs possess capability in self-renewing and differentiating, the hierarchy of CSCs during tumor growth is highly plastic. This plasticity in CSCs fate and function can be regulated by signals from the tumor microenvironment. One emerging pathway in CSCs that connects the alteration in microenvironment and signaling network in cancer cells is the hexosamine biosynthetic pathway (HBP). The final product of HBP, UDP-N-acetylglucosamine (UDP-GlcNAc), is utilized for glycosylating of membrane and secreted proteins, but also nuclear and cytoplasmic proteins by the post-translational modification O-GlcNAcylation. O-GlcNAcylation and its enzyme, O-GlcNAc transferase (OGT), are upregulated in nearly all cancers and been linked to regulate many cancer cell phenotypes. Recent studies have begun to connect OGT and O-GlcNAcylation to regulation of CSCs. In this review, we will discuss the emerging role of OGT and O-GlcNAcylation in regulating fate and plasticity of CSCs, as well as the potential in targeting OGT/O-GlcNAcylation in CSCs.

Molecular and Immune Phenotypic Modifications during Metastatic Dissemination in Lung Carcinogenesis

Simple Summary

Metastatic cancer is a multifaceted complex disease. It is mainly characterized by a strong invasive potential, metastasis, resistance to therapy, and poor clinical prognosis. Although the use of immune checkpoint inhibitors (ICI) has substantially improved cancer treatment and therapy, there are many significant challenges to be addressed. In this review, we provide an overview of the mechanisms used by metastatic or disseminating tumor cells (DTCs) in order to understand cancer progression to metastasis, and establish new strategies for novel therapeutic interventions.

Abstract

The tumor microenvironment plays a key role in the progression of lung tumorigenesis, progression, and metastasis. Recent data reveal that disseminated tumor cells (DTCs) appear to play a key role in the development and progression of lung neoplasiaby driving immune system dysfunction and established immunosuppression, which is vital for evading the host immune response. As a consequence, in this review we will discuss the role and function of DTCs in immune cell signaling routes which trigger drug resistance and immunosuppression. We will also discuss the metabolic biology of DTCs, their dormancy, and their plasticity, which are critical for metastasis and drive lung tumor progression. Furthermore, we will consider the crosstalk between DTCs and myeloid cells in tumor-related immunosuppression. Specifically, we will investigate the molecular immune-related mechanisms in the tumor microenvironment that lead to decreased drug sensitivity and tumor relapse, along with strategies for reversing drug resistance and targeting immunosuppressive tumor networks. Deciphering these molecular mechanisms is essential for preclinical and clinical investigations in order to enhance therapeutic efficacy. Furthermore, a better understanding of these immune cell signaling pathways that drive immune surveillance, immune-driven inflammation, and tumor-related immunosuppression is necessary for future personalized therapeutic approaches.

Insights Into Vascular Anomalies, Cancer, and Fibroproliferative Conditions: The Role of Stem Cells and the Renin-Angiotensin System

Cells exhibiting embryonic stem cell (ESC) characteristics have been demonstrated in vascular anomalies (VAs), cancer, and fibroproliferative conditions, which are commonly managed by plastic surgeons and remain largely unsolved. The efficacy of the mTOR inhibitor sirolimus, and targeted therapies that block the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways in many types of cancer and VAs, further supports the critical role of ESC-like cells in the pathogenesis of these conditions. ESC-like cells in VAs, cancer, and fibroproliferative conditions express components of the renin-angiotensin system (RAS) – a homeostatic endocrine signaling cascade that regulates cells with ESC characteristics. ESC-like cells are influenced by the Ras/BRAF/MEK/ERK1/2 and PI3KCA/AKT/mTOR pathways, which directly regulate cellular proliferation and stemness, and interact with the RAS at multiple points. Gain-of-function mutations affecting these pathways have been identified in many types of cancer and VAs, that have been treated with targeted therapies with some success. In cancer, the RAS promotes tumor progression, treatment resistance, recurrence, and metastasis. The RAS modulates cellular invasion, migration, proliferation, and angiogenesis. It also indirectly regulates ESC-like cells via its direct influence on the tissue microenvironment and by its interaction with the immune system. In vitro studies show that RAS inhibition suppresses the hallmarks of cancer in different experimental models. Numerous epidemiological studies show a reduced incidence of cancer and improved survival outcomes in patients taking RAS inhibitors, although some studies have shown no such effect. The discovery of ESC-like cells that express RAS components in infantile hemangioma (IH) underscores the paradigm shift in the understanding of its programmed biologic behavior and accelerated involution induced by β-blockers and angiotensin-converting enzyme inhibitors. The findings of SOX18 inhibition by R-propranolol suggests the possibility of targeting ESC-like cells in IH without β-adrenergic blockade, and its associated side effects. This article provides an overview of the current knowledge of ESC-like cells and the RAS in VAs, cancer, and fibroproliferative conditions. It also highlights new lines of research and potential novel therapeutic approaches for these unsolved problems in plastic surgery, by targeting the ESC-like cells through manipulation of the RAS, its bypass loops and converging signaling pathways using existing low-cost, commonly available, and safe oral medications.

Roles of Wnt/β-catenin signaling pathway related microRNAs in esophageal cancer

MicroRNAs (miRNAs) are endogenous, noncoding, single-stranded small RNAs that regulate expression of tumor suppressor genes and oncogenes and are involved in almost all tumor-related processes. MiRNA dysregulation plays an important role in the occurrence and development of esophageal cancer through specific signal pathways, including the Wnt/β-catenin signaling pathway, and is closely related to the malignant characteristics of esophageal cancer. The interaction between miRNAs and the Wnt/β-catenin signaling pathway, which is specifically expressed in esophageal cancer tissues, shows potential as a new biomarker and therapeutic target. This article reviews the role of miRNAs related to the Wnt pathway in the carcinogenesis of esophageal carcinoma and its role in Wnt signal transduction. The content of this review can be used as the basis for formulating or improving the treatment strategy of esophageal cancer.

Application of Microfluidic Systems for Breast Cancer Research

Cancer is a disease in which cells in the body grow out of control; breast cancer is the most common cancer in women in the United States. Due to early screening and advancements in therapeutic interventions, deaths from breast cancer have declined over time, although breast cancer remains the second leading cause of cancer death among women. Most deaths are due to metastasis, as cancer cells from the primary tumor in the breast form secondary tumors in remote sites in distant organs. Over many years, the basic biological mechanisms of breast cancer initiation and progression, as well as the subsequent metastatic cascade, have been studied using cell cultures and animal models. These models, although extremely useful for delineating cellular mechanisms, are poor predictors of physiological responses, primarily due to lack of proper microenvironments. In the last decade, microfluidics has emerged as a technology that could lead to a paradigm shift in breast cancer research. With the introduction of the organ-on-a-chip concept, microfluidic-based systems have been developed to reconstitute the dominant functions of several organs. These systems enable the construction of 3D cellular co-cultures mimicking in vivo tissue-level microenvironments, including that of breast cancer. Several reviews have been presented focusing on breast cancer formation, growth and metastasis, including invasion, intravasation, and extravasation. In this review, realizing that breast cancer can recur decades following post-treatment disease-free survival, we expand the discussion to account for microfluidic applications in the important areas of breast cancer detection, dormancy, and therapeutic development. It appears that, in the future, the role of microfluidics will only increase in the effort to eradicate breast cancer.

GLI1-targeting drugs induce replication stress and homologous recombination deficiency and synergize with PARP-targeted therapies in triple negative breast cancer cells

Triple negative breast cancer (TNBC), an aggressive and highly metastatic subtype of breast cancer. Glioma-associated oncogene 1 (GLI1) is a transcription factor and effector of the Hedgehog (Hh) signaling pathway, and is predictive of poor survival for TNBC patients. A nanostring DNA Damage Response (DDR) mRNA panel was used to identify GLI1-induced regulation of DDR genes. Western blots, immunohistochemistry and immunofluorescence were used to evaluate protein expression. Colony assays and mammosphere formation assays were utilized to assess survival of cancer cells. Flow cytometry analyses were employed to evaluate changes in the cell cycle profile, and DNA fiber assays were used to analyze alterations in replication dynamics in TNBC cells. The UALCAN portal and Ensemble programs were used for computational analysis of TCGA data. CompuSyn software was used to calculate combination index (CI) values to assess synergism in drug combination experiments. Inhibition of GLI1 in TNBC cells transcriptionally downregulate expression of FANCD2 and its foci formation, and causes a homologous recombination repair (HR) deficiency. As HR-deficient cancer cells are sensitive to PARP-targeted therapies, we evaluated a combination of the GLI1 inhibitor, GANT61, and a PARP inhibitor (olaparib) in TNBC cells. Combination of GANT61 and olaparib elevated DNA damage levels and these drug combinations caused synergistic lethality to TNBC cells. Aberrantly activated GLI1 regulates HR-mediated DNA repair by transcriptionally regulating FANCD2 to overcome chemotherapy-induced replication stress and DNA damage, and it contributes to resistance of TNBC cells to therapeutics.

Luteolin Inhibits Breast Cancer Stemness and Enhances Chemosensitivity through the Nrf2-Mediated Pathway

Cancer stem cells (CSCs) are subpopulations of tumor masses with unique abilities in self-renewal, stemness maintenance, drug resistance, and the promotion of cancer recurrence. Recent studies have suggested that breast CSCs play essential roles in chemoresistance. Therefore, new agents that selectively target such cells are urgently required. Reactive oxygen species (ROS)-producing enzymes are the reason for an elevated tumor oxidant status. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor, which upon detecting cellular oxidative stress, binds to the promoter region of antioxidant genes. By triggering a cytoprotective response, Nrf2 maintains cellular redox status. Cripto-1 participates in the self-renewal of CSCs. Herein, luteolin, a flavonoid found in Taraxacum&nbsp;officinale extract, was determined to inhibit the expressions of stemness-related transcriptional factors, the ATP-binding cassette transporter G2 (ABCG2), CD44, aldehyde dehydrogenase 1 activity as well as the sphere formation properties of breast CSCs. Furthermore, luteolin suppressed the protein expressions of Nrf2, heme oxygenase 1 (HO-1), and Cripto-1 which have been determined to contribute critically to CSC features. The combination of luteolin and the chemotherapeutic drug, Taxol, resulted in enhanced cytotoxicity to breast cancer cells. These findings suggest that luteolin treatment significantly attenuated the hallmarks of breast cancer stemness by downregulating Nrf2-mediated expressions. Luteolin constitutes a potential agent for use in cancer stemness-targeted breast cancer treatments.

Reducing tumor invasiveness by ramucirumab and TGF-β receptor kinase inhibitor in a diffuse-type gastric cancer patient-derived cell model

BACKGROUND

Diffuse-type gastric cancer (GC) is known to be more aggressive and relatively resistant to conventional chemotherapy. Hence, more optimized treatment strategy is urgently needed in diffuse-type GC.

METHODS

Using a panel of 10 GC cell lines and 3 GC patient-derived cells (PDCs), we identified cell lines with high EMTness which is a distinct feature for diffuse-type GC. We treated GC cells with high EMTness with ramucirumab alone, TGF-β receptor kinase inhibitor (TEW-7197) alone, or in combination to investigate the drug's effects on invasiveness, spheroid formation, EMT marker expression, and tumor-induced angiogenesis using a spheroid-on-a-chip model.

RESULTS

Both TEW-7197 and ramucirumab treatments profoundly decreased invasiveness of EMT-high cell lines and PDCs. With a 3D tumor spheroid-on-a-chip, we identified versatile influence of co-treatment on cancer cell-induced blood vessel formation as well as on EMT progression in tumor spheroids. The 3D tumor spheroid-on-a-chip demonstrated that TEW-7197 + ramucirumab combination significantly decreased PDC-induced vessel formation.

CONCLUSIONS

In this study, we showed TEW-7197 and ramucirumab considerably decreased invasiveness, thus EMTness in a panel of diffuse-type GC cell lines including GC PDCs. Taken together, we confirmed that combination of TEW-7197 and ramucirumab reduced tumor spheroid and GC PDC-induced blood vessel formation concomitantly in the spheroid-on-a-chip model.

Effect of HDAC9 inhibition on epithelial-mesenchymal transition in CD133+ prostate cancer cell lines

A small fraction of cancer cells known as cancer stem cells (CSCs) are considered to give rise to differentiated cancer cells and have been proposed to predict cancer recurrence and metastasis. There is further evidence that CSCs may act as metastatic precursors of epithelial-mesenchymal transition (EMT). In the present study, we investigated the key molecules involved in maintaining the stability of CSCs by inducing ectopic overexpression of CD133 to characterize EMT in human prostate cancer cell lines, including PC-3, DU145, and LnCaP cells. Additionally, we investigated whether a specific inhibitor of concomitantly expressed metastasis-related genes could alleviate EMT properties in CD133-overexpressing prostate cancer cells. Ectopic overexpression of CD133 in PC-3, DU145, and LnCaP cells led to an increase in the expression of HDAC9. Moreover, HDAC9 inhibition led to a decrease in EMT properties along with increased E-cadherin expression, a narrower wound gap distance, and enhanced cell invasiveness through the suppression of β-catenin activation and its translocation to the nucleus. Overall, these results suggest that HDAC9 inhibition plays a functional role in the modulation of EMT properties in CSC-like prostate cancer cells. Therefore, these findings could facilitate the development of therapeutic strategies for controlling prostate cancer metastasis.

Epigenetic Regulation of Breast Cancer Stem Cells Contributing to Carcinogenesis and Therapeutic Implications

Globally, breast cancer has remained the most commonly diagnosed cancer and the leading cause of cancer death among women. Breast cancer is a highly heterogeneous and phenotypically diverse group of diseases, which require different selection of treatments. Breast cancer stem cells (BCSCs), a small subset of cancer cells with stem cell-like properties, play essential roles in breast cancer progression, recurrence, metastasis, chemoresistance and treatments. Epigenetics is defined as inheritable changes in gene expression without alteration in DNA sequence. Epigenetic regulation includes DNA methylation and demethylation, as well as histone modifications. Aberrant epigenetic regulation results in carcinogenesis. In this review, the mechanism of epigenetic regulation involved in carcinogenesis, therapeutic resistance and metastasis of BCSCs will be discussed, and finally, the therapies targeting these biomarkers will be presented.

A three dimensional in vivo model of breast cancer using a thermosensitive chitosan-based hydrogel and 4 T1 cell line in Balb/c

The two-dimensional (2D) models of breast cancer still exhibit a limited success. Whereas, three-dimensional (3D) models provide more similar conditions to the tumor for growth of cancer cells. In this regard, a 3D in vivo model of breast cancer using 4 T1 cells and chitosan-based thermosensitive hydrogel were designed. Chitosan/β-glycerol phosphate hydrogel (Ch/β-GP) was prepared with a final ratio of 2% and 10%. The hydrogel properties were examined by Fourier transformed infrared spectroscopy, MTT assay, pH, scanning electron microscopy, and biodegradability assay. 3D model of breast cancer was induced by injection of 1 × 106 4 T1 cells in 100 μl hydrogel and 2D model by injection of 1 × 106 4 T1 cells in 100 μl phosphate-buffered saline (PBS) subcutaneously. After 3 weeks, induced tumors were evaluated by size and weight determination, ultrasound, hematoxylin- and eosin and Masson's trichrome staining and evaluating of cancer stem cells with CD44 and CD24 markers. The results showed that hydrogel with physiological pH had no cytotoxicity. In 3D model, tumor size and weight increased significantly (p ≤ .001) in comparison with 2D model. Histological and ultrasound analysis showed that 3D tumor model was more similar to breast cancer. Expression of CD44 and CD24 markers in the 3D model was more than 2D model (p ≤ .001). This 3D in vivo model of breast cancer mimicked native tumor and showed malignant tissue properties. Therefore, the use of such models can be effective in various cancer studies, especially in the field of cancer stem cells.

Porphyromonas gingivalis promotes tumor progression in esophageal squamous cell carcinoma

PURPOSE

Increasing evidence indicates that the microbiome may influence tumor growth and modulate the tumor microenvironment of gastrointestinal cancers. However, the role of oral bacteria in the development of esophageal squamous cell carcinoma (EsoSCC) has remained unclear. Herein, we investigated the relationship between the periodontal pathogen Porphyromonas gingivalis and EsoSCC.

METHODS

To identify bacterial biomarkers associated with EsoSCC, we analyzed microbiomes in oral biofilms. The presence of P. gingivalis in esophageal tissues and relationships of P. gingivalis infection with clinicopathologic characteristics in 156 patients with EsoSCC were assessed using immunohistochemistry. The role of P. gingivalis infection in in vitro and in vivo EsoSCC progression was also assessed.

RESULTS

Microbiota profiles in oral biofilms revealed that P. gingivalis abundance was associated with an increased risk of EsoSCC development. In total, 57% of patients with EsoSCC were found to be infected with P. gingivalis. The presence of P. gingivalis was found to be associated with advanced clinical stages and a poor prognosis. It was also found to be associated with an elevated esophageal cancer incidence in a 4-nitroquinoline 1-oxide-induced mouse model and with an increased xenograft tumor growth. P. gingivalis infection increased interleukin (IL)-6 production and it promoted epithelial-mesenchymal transition and the recruitment of myeloid-derived suppressor cells. Furthermore, inhibited IL-6 signaling attenuated the tumor-promoting effects of P. gingivalis in 4-nitroquinoline 1-oxide-treated mice and xenograft mouse models.

CONCLUSIONS

Our data indicate that P. gingivalis may promote esophageal cancer development and progression. Direct targeting of P. gingivalis or concomitant IL-6 signaling may be a promising strategy to prevent and/or treat EsoSCC associated with P. gingivalis infection.

Oct4-Mediated Inhibition of Lsd1 Activity Promotes the Active and Primed State of Pluripotency Enhancers

An aberrant increase in pluripotency gene (PpG) expression due to enhancer reactivation could induce stemness and enhance the tumorigenicity of cancer stem cells. Silencing of PpG enhancers (PpGe) during embryonic stem cell differentiation involves Lsd1-mediated H3K4me1 demethylation and DNA methylation. Here, we observed retention of H3K4me1 and DNA hypomethylation at PpGe associated with a partial repression of PpGs in F9 embryonal carcinoma cells (ECCs) post-differentiation. H3K4me1 demethylation in F9 ECCs could not be rescued by Lsd1 overexpression. Given our observation that H3K4me1 demethylation is accompanied by strong Oct4 repression in P19 ECCs, we tested if Oct4 interaction with Lsd1 affects its catalytic activity. Our data show a dose-dependent inhibition of Lsd1 activity by Oct4 and retention of H3K4me1 at PpGe in Oct4-overexpressing P19 ECCs. These data suggest that Lsd1-Oct4 interaction in cancer stem cells could establish a "primed" enhancer state that is susceptible to reactivation, leading to aberrant PpG expression.

Identification of Immune-Related Therapeutically Relevant Biomarkers in Breast Cancer and Breast Cancer Stem Cells by Transcriptome-Wide Analysis: A Clinical Prospective Study

Cancer stem cells (CSCs) represent a subset of tumor cells that are responsible for recurrence and metastasis of tumors. These cells are resistant to radiotherapy and chemotherapy. Immunotherapeutic strategies that target CSCs specifically have provided initial results; however, the mechanism of action of these strategies is unclear. The data were requested from The Cancer Genome Atlas and Genotype-Tissue Expression, followed with the survival analysis and weighted gene co-expression network analysis to detect survival and stemness related genes. Patients were divided into three groups based on their immune status by applying single sample GSEA (ssGSEA) with proven dependability by ESTIMATE analysis. The filtered key genes were analyzed using oncomine, GEPIA, HPA, qRT-PCR, and functional analysis. Patients in a group with a higher stemness and a lower immune infiltration showed a worse overall survival probability, stemness and immune infiltration characteristics of breast cancer progressed in a non-linear fashion. Thirteen key genes related to stemness and immunity were identified and the functional analysis indicated their crucial roles in cell proliferation and immune escape strategies. The qRT-PCR results showed that the expression of PIMREG and MTFR2 differed in different stages of patients. Our study revealed a promising potential for CSC-target immunotherapy in the early stage of cancer and a probable value for PIMREG and MTFR2 as biomarkers and targets for immunotherapy.

Therapeutic Targeting of the Tumour Microenvironment in Metastatic Colorectal Cancer

Liver metastasis is the primary contributor to the death of patients with colorectal cancer. Despite the overall success of current treatments including targeted therapy, chemotherapy, and immunotherapy combinations in colorectal cancer patients, the prognosis of patients with liver metastasis remains poor. Recent studies have highlighted the importance of the tumour microenvironment and the crosstalk within that determines the fate of circulating tumour cells in distant organs. Understanding the interactions between liver resident cells and tumour cells colonising the liver opens new therapeutic windows for the successful treatment of metastatic colorectal cancer. Here we discuss critical cellular interactions within the tumour microenvironment in primary tumours and in liver metastases that highlight potential therapeutic targets. We also discuss recent therapeutic advances for the treatment of metastatic colorectal cancer.

Role of eIF4A1 in triple-negative breast cancer stem-like cell-mediated drug resistance

In cap-dependent translation, the eukaryotic translation initiation factor 4A (eIF4A1) is an mRNA helicase is involved in unwinding of the secondary structure, such as the stem-loops, at the 5'-leader regions of the key oncogenic mRNAs. This facilitates ribosomal scanning and translation of the oncogenic mRNAs. eIF4A1 has a regulatory role in translating many oncoproteins that have vital roles in several steps of metastases. Sridharan et. al. have discovered and provide a novel insight into how eIF4A1 can play a regulatory role in drug resistance by influencing the levels of pluripotent Yamanaka transcription factors and ATP-binding cassette (ABC) transporters in triple-negative breast cancer (TNBC) stem-like cells. These findings may help us understand the molecular underpinnings of chemoresistance, especially in established metastases in TNBC. Importantly, eIF4A1 may form a novel clinical target in metastatic TNBC and the drug eFT226 from Effector Therapeutics targeting eIF4A1 is already in phase1-2 clinical trial.

Optimizing Silanization to Functionalize Stainless Steel Wire: Towards Breast Cancer Stem Cell Isolation

Chemically modified metal surfaces have been used to recognize and capture specific cell types and biomolecules. In this work, stainless steel wires were functionalized with aptamers against breast cancer stem cell markers. Stainless steel wires were first electropolished and silanized via electrodeposition. Aptamers were then attached to the silanized surface through a cross-linker. The functionalized wires were able to capture the target cells in an in vitro test. During surface modification steps, wires were analyzed by atomic force microscopy, cyclic voltammetry, scanning electron and fluorescence microscopy to determine their surface composition and morphology. Optimized conditions of silanization (applied potential, solution pH, heat treatment temperature) for obtaining an aptamer-functionalized wire were determined in this work together with the use of several surface characterization techniques suitable for small-sized and circular wires. These modified wires have potential applications for the in vivo capture of target cells in blood flow, since their small size allows their insertion as standard guidewires in biomedical devices.

Combating metastasis of breast cancer cells with a carboplatin analogue containing an all-trans retinoic acid ligand

Pt-ATRA, a carboplatin analogue containing an all-trans retinoic acid (ATRA) derivative ligand, was synthesized via a click reaction. Upon cellular internalization, Pt-ATRA exhibits a dual function, releasing an active Pt(ii) moiety to induce cell apoptosis and ATRA to inhibit tumor metastasis.

Exploring the biological hallmarks of cancer of unknown primary: where do we stand today?

Cancer of unknown primary (CUP) affects a small percentage of the general population. Nonetheless, a substantial number of these patients have a poor prognosis and consequently succumb to their illness within a year of diagnosis. The natural history of CUP is characterised by early metastasis from the unknown primary site, aggressive course and resistance to conventional chemotherapy. Unfortunately, the processes by which this orphan disease originates and progresses have not been fully elucidated and its biology remain unclear. Despite the conceptual progress in genetic and molecular profiling made over the past decade, recognition of the genetic and molecular abnormalities involved in CUP, as well as the identification of the tissue of origin remain unresolved issues. This review will outline the biology of CUP by exploring the hallmarks of cancer in order to rationalise the complexities of this enigmatic syndrome. This approach will help the reader to understand where research efforts currently stand and the pitfalls of this quest.

Hsa_circ_002178 Promotes the Growth and Migration of Breast Cancer Cells and Maintains Cancer Stem-like Cell Properties Through Regulating miR-1258/KDM7A Axis

Breast cancer (BrCa) is the most common malignancy in women. Accumulating evidence demonstrated that abnormal circRNA expression is associated with the occurrence and progression of tumors. We analyzed the GSE101123 data and found that the expression of hsa_circ_002178 (circ_002178) was significantly increased in BrCa tissues. However, the role and possible underlying mechanisms of circ_002178 in BrCa still remain unrevealed. In this investigation, the expression levels of circ_002178 in cancer tissues or BrCa cells were significantly upregulated compared with those in paracancer tissues or normal cells. High expression of circ_002178 was correlated with the low survival rate, clinical tumor size, lymph node metastasis, and tumor, nodes, and metastases grade. After microsphere culture, the expression of circ_002178 in SUM149PT and MDA-MB-231 cells was significantly increased. Further investigation exhibited that overexpression of circ_002178 contributed to the formation of microspheres, the elevated protein levels of stemness marker, and the increased activity of ALDH1 in SUM149PT cells. Besides, the overexpression of circ_002178 also significantly promoted the growth, invasion, and migration of BrCa cells. Correspondingly, the knockdown of circ_002178 showed the opposite result in MDA-MB-231 cells. Hsa_circ_002178 was further proved to downregulate the level of miR-1258 and reduce the inhibitory effect of miR-1258 on KDM7A, thus regulating the stem-like characteristics of BrCa cells and promoting the growth and migration of BrCa cells. Taken together, targeting the circ_002178/miR-1258/KDM7A axis may be a prospective strategy for the diagnosis and therapies of BrCa in the future.

Lichen Secondary Metabolite Physciosporin Decreases the Stemness Potential of Colorectal Cancer Cells

Secondary metabolites of lichens are promising bioresources for candidate anti-cancer drugs. Accordingly, several approaches have been proposed for screening these molecules for novel anti-cancer lead compounds. In this study, we found that a non-toxic concentration of physciosporin, a compound isolated from Pseudocyphellaria granulata, significantly decreased colony formation on soft agar and spheroid formation by CSC221 cancer stem-like cells. Physciosporin also decreased spheroid formation in other colorectal cancer cell lines, including DLD1, Caco2, and HT29. Aldehyde dehydrogenase-1 (ALDH1), the most important cancer stem marker, was sharply downregulated at both the protein and mRNA level following treatment with physciosporin. Physciosporin also decreased the transcriptional activity of the glioma-associated oncogene homolog zinc finger protein (Gli), as well as the Hes1 and CSL promoters, in reporter assays. Moreover, the drug significantly suppressed spheroid formation in CSC221 cells overexpressing Gli1/2 or EN1 (an S2-cleaved but membrane-tethered form of human Notch1) but did not suppress spheroid formation in cells overexpressing both Gli1/2 and ∆EN1, suggesting that physciosporin suppresses colon cancer cell stemness through the Sonic hedgehog and Notch signaling pathways. Together, these results demonstrate for the first time that physciosporin is a potent inhibitor of colorectal cancer cell stemness.

Fibroblast growth factor-10 and epithelial-mesenchymal transition in colorectal cancer

As an inducer of epithelial-mesenchymal transition (EMT), fibroblast growth factor-10 (FGF-10) has a role in cell proliferation and differentiation in the embryo in addition to invasion and metastasis during carcinogenesis. In this study, we aimed to investigate the FGF-10 gene expression in tumor tissues based on the pathological feature of tumor related to EMT and metastasis. 62 tumors were obtained from 62 colorectal cancer patients during surgery. The pathological characteristics of the patients were carefully collected and classified by Iran National Tumor Bank. To quantify FGF-10 gene expression, RNA extraction, reverse transcription-PCR and real-time PCR were respectively performed. In addition, three colorectal cancer cell lines including LS174T, SW-948 and SW-480 were collected and cultured for further molecular analysis. Consequently, FGF-10 gene expression showed increased expression level in LS174T and SW-948 while it displayed decreased level in SW-480. Considering the tumor samples, we found an upregulation of FGF-10 gene expression in 52.1 % of all tumors in stage III and only in 9.09 % of all tumors in stage I. Also, there were an upregulation of FGF-10 gene expression in 50 % of all positive lymph invasion patients. Besides, FGF-10 gene upregulation was observed in 50 % of all tumors with a size larger than 5 cm (P value < 0.05) and 69 % of all tumors located in the colon (P value < 0.05). To our knowledge, this is the first time that FGF-10 expression is reported based on pathological features of colorectal cancer.

A nomogram predicting the recurrence of hepatocellular carcinoma in patients after laparoscopic hepatectomy

BACKGROUND

Patients with hepatocellular carcinoma (HCC) undergoing surgical resection still have a high 5-year recurrence rate (~ 60%). With the development of laparoscopic hepatectomy (LH), few studies have compared the efficacy between LH and traditional surgical approach on HCC. The objective of this study was to establish a nomogram to evaluate the risk of recurrence in HCC patients who underwent LH.

METHODS

The clinical data of 432 patients, pathologically diagnosed with HCC, underwent LH as initial treatment and had surgical margin > 1 cm were collected. The significance of their clinicopathological features to recurrence-free survival (RFS) was assessed, based on which a nomogram was constructed using a training cohort (n = 324) and was internally validated using a temporal validation cohort (n = 108).

RESULTS

Hepatitis B surface antigen (hazard ratio [HR], 1.838; P = 0.044), tumor number (HR, 1.774; P = 0.003), tumor thrombus (HR, 2.356; P = 0.003), cancer cell differentiation (HR, 0.745; P = 0.080), and microvascular tumor invasion (HR, 1.673; P  =0.007) were found to be independent risk factors for RFS in the training cohort, and were used for constructing the nomogram. The C-index for RFS prediction in the training cohort using the nomogram was 0.786, which was higher than that of the 8th edition of the American Joint Committee on Cancer TNM classification (C-index, 0.698) and the Barcelona Clinic Liver Cancer staging system (C-index, 0.632). A high consistency between the nomogram prediction and actual observation was also demonstrated by a calibration curve. An improved predictive benefit in RFS and higher threshold probability of the nomogram were determined by receiver operating characteristic curve analysis, which was also confirmed in the validation cohort compared to other systems.

CONCLUSIONS

We constructed and validated a nomogram able to quantify the risk of recurrence after initial LH for HCC patients, which can be clinically implemented in assisting the planification of individual postoperative surveillance protocols.

Effect of Tumor Burden on Tumor Aggressiveness and Immune Modulation in Prostate Cancer: Association with IL-6 Signaling

Local treatment is known to improve survival in men with locally advanced prostate cancer (LAPC), but the underlying mechanisms remain unclear. In the present study, we examined the role of tumor burden in tumor aggressiveness, as well as the pathway responsible for these changes. We used human and murine prostate cancer cell lines to examine the role of tumor burden in tumor aggressiveness, as well as its correlation with cancer stem cell (CSC) marker levels and IL-6 signaling. Furthermore, 167 prostate cancer biopsy specimens were analyzed in terms of correlations of IL-6 and CD44 levels with clinical patient characteristics. Data from preclinical models showed that larger tumor burden was associated with more aggressive tumor growth associated and increased CD44 expression. Using cellular experiments and orthotopic tumor models, we showed that CD44+ prostate cancer cells have CSC-like properties, enhanced epithelial–mesenchymal transition (EMT), and a more immunosuppressive microenvironment. There was a significant correlation between IL-6 and CD44 levels based on in vitro testing of clinical samples. Blockade of IL-6/STAT3 signaling attenuated the expression of CD44, CSC-like properties, and aggressive tumor behavior in vitro and in vivo. In conclusion, CD44 expression is significantly associated with tumor aggressiveness in prostate cancer and activation of IL-6 signaling leads to a suitable microenvironment for the induction of CD44 expression. Based on our study, reduced tumor burden was associated with attenuated IL-6 signaling and augmented tumor rejection in the microenvironment, which might mediate the benefit of clinical adoption with aggressive local therapy.

Cancer stem cells: A review from origin to therapeutic implications

Cancer stem cells (CSCs), also known as tumor-initiating cells (TICs), are elucidated as cells that can perpetuate themselves via autorestoration. These cells are highly resistant to current therapeutic approaches and are the main reason for cancer recurrence. Radiotherapy has made a lot of contributions to cancer treatment. However, despite continuous achievements, therapy resistance and tumor recurrence are still prevalent in most patients. This resistance might be partly related to the existence of CSCs. In the present study, recent advances in the investigation of different biological properties of CSCs, such as their origin, markers, characteristics, and targeting have been reviewed. We have also focused our discussion on radioresistance and adaptive responses of CSCs and their related extrinsic and intrinsic influential factors. In summary, we suggest CSCs as the prime therapeutic target for cancer treatment.

Head and neck cancer management and cancer stem cells implication

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are heterogeneous in nature. Risk factors for HNSCCs are smoking, excessive alcohol consumption, and the human papilloma virus. Conventional treatments are surgery, radiotherapy, chemotherapy, or a combined modality; however, no international standard mode of therapy exists. In contrast to the conventional model of clonal evolution in tumor development, there is a newly proposed theory based on the activity of cancer stem cells (CSCs) as the model for carcinogenesis. This “CSC hypothesis” may explain the high mortality rate, low response to treatments, and tendency to develop multiple tumors for HNSCC patients. We review current knowledge on HNSCC etiology and treatment, with a focus on CSCs, including their origins, identifications, and effects on therapeutic options.