Nanog Signaling Mediates Radioresistance in ALDH-Positive Breast Cancer Cells

Transcriptional regulation of cancer stem cell: regulatory factors elucidation and cancer treatment strategies

Cancer stem cells (CSCs) were first discovered in the 1990s, revealing the mysteries of cancer origin, migration, recurrence and drug-resistance from a new perspective. The expression of pluripotent genes and complex signal regulatory networks are significant features of CSC, also act as core factors to affect the characteristics of CSC. Transcription is a necessary link to regulate the phenotype and potential of CSC, involving chromatin environment, nucleosome occupancy, histone modification, transcription factor (TF) availability and cis-regulatory elements, which suffer from ambient pressure. Especially, the expression and activity of pluripotent TFs are deeply affected by both internal and external factors, which is the foundation of CSC transcriptional regulation in the current research framework. Growing evidence indicates that regulating epigenetic modifications to alter cancer stemness is effective, and some special promoters and enhancers can serve as targets to influence the properties of CSC. Clarifying the factors that regulate CSC transcription will assist us directly target key stem genes and TFs, or hinder CSC transcription through environmental and other related factors, in order to achieve the goal of inhibiting CSC and tumors. This paper comprehensively reviews the traditional aspects of transcriptional regulation, and explores the progress and insights of the impact on CSC transcription and status through tumor microenvironment (TME), hypoxia, metabolism and new meaningful regulatory factors in conjunction with the latest research. Finally, we present opinions on omnidirectional targeting CSCs transcription to eliminate CSCs and address tumor resistance.

Inhibition of γ-secretase/Notch pathway as a potential therapy for reversing cancer drug resistance

The mechanism of tumor drug resistance is complex and may involve stem cell maintenance, epithelial-mesenchymal transition, the activation of survival signaling pathways, transporter protein expression, and tumor microenvironment remodeling, all of which are linked to γ-secretase/Notch signaling. Increasing evidence has shown that the activation of the γ-secretase/Notch pathway is a key driver of cancer progression and drug resistance development and that γ-secretase inhibitors (GSIs) may be the most promising agents for reversing chemotherapy resistance of tumors by targeting the γ-secretase/Notch pathway. Here, we systematically summarize the roles in supporting γ-secretase/Notch activation-associated transformation of cancer cells into cancer stem cells, promotion of the EMT process, PI3K/Akt, MEK/ERK and NF-κB activation, enhancement of ABC transporter protein expression, and TME alteration in mediating tumor drug resistance. Subsequently, we analyze the mechanism of GSIs targeting the γ-secretase/Notch pathway to reverse tumor drug resistance and propose the outstanding advantages of GSIs in treating breast cancer drug resistance over other tumors. Finally, we emphasize that the development of GSIs for reversing tumor drug resistance is promising.

ALDEFLUOR activity, ALDH isoforms, and their clinical significance in cancers

High aldehyde dehydrogenase (ALDH) activity is a metabolic feature of adult stem cells and various cancer stem cells (CSCs). The ALDEFLUOR system is currently the most commonly used method for evaluating ALDH enzyme activity in viable cells. This system is applied extensively in the isolation of normal stem cells and CSCs from heterogeneous cell populations. For many years, ALDH1A1 has been considered the most important subtype among the 19 ALDH family members in determining ALDEFLUOR activity. However, in recent years, studies of many types of normal and tumour tissues have demonstrated that other ALDH subtypes can also significantly influence ALDEFLUOR activity. In this article, we briefly review the relationships between various members of the ALDH family and ALDEFLUOR activity. The clinical significance of these ALDH isoforms in different cancers and possible directions for future studies are also summarised.

The strategies to cure cancer patients by eradicating cancer stem-like cells

Cancer stem-like cells (CSCs), a subpopulation of cancer cells, possess remarkable capability in proliferation, self-renewal, and differentiation. Their presence is recognized as a crucial factor contributing to tumor progression and metastasis. CSCs have garnered significant attention as a therapeutic focus and an etiologic root of treatment-resistant cells. Increasing evidence indicated that specific biomarkers, aberrant activated pathways, immunosuppressive tumor microenvironment (TME), and immunoevasion are considered the culprits in the occurrence of CSCs and the maintenance of CSCs properties including multi-directional differentiation. Targeting CSC biomarkers, stemness-associated pathways, TME, immunoevasion and inducing CSCs differentiation improve CSCs eradication and, therefore, cancer treatment. This review comprehensively summarized these targeted therapies, along with their current status in clinical trials. By exploring and implementing strategies aimed at eradicating CSCs, researchers aim to improve cancer treatment outcomes and overcome the challenges posed by CSC-mediated therapy resistance.

Multi-omics profiling reveals cellular pathways and functions regulated by ALDH1B1 in colon cancer cells

Colon cancer is the third leading cause of cancer death globally. Although early screenings and advances in treatments have reduced mortality since 1970, identification of novel targets for therapeutic intervention is needed to address tumor heterogeneity and recurrence. Previous work identified aldehyde dehydrogenase 1B1 (ALDH1B1) as a critical factor in colon tumorigenesis. To investigate further, we utilized a human colon adenocarcinoma cell line (SW480) in which the ALDH1B1 protein expression has been knocked down by 80% via shRNA. Through multi-omics (transcriptomics, proteomics, and untargeted metabolomics) analysis, we identified the impact of ALDH1B1 knocking down (KD) on molecular signatures in colon cancer cells. Suppression of ALDH1B1 expression resulted in 357 differentially expressed genes (DEGs), 191 differentially expressed proteins (DEPs) and 891 differentially altered metabolites (DAMs). Functional annotation and enrichment analyses revealed that: (1) DEGs were enriched in integrin-linked kinase (ILK) signaling and growth and development pathways; (2) DEPs were mainly involved in apoptosis signaling and cellular stress response pathways; and (3) DAMs were associated with biosynthesis, intercellular and second messenger signaling. Collectively, the present study provides new molecular information associated with the cellular functions of ALDH1B1, which helps to direct future investigation of colon cancer.

Human Aldehyde Dehydrogenases: A Superfamily of Similar Yet Different Proteins Highly Related to Cancer

The superfamily of human aldehyde dehydrogenases (hALDHs) consists of 19 isoenzymes which are critical for several physiological and biosynthetic processes and play a major role in the organism's detoxification via the NAD(P) dependent oxidation of numerous endogenous and exogenous aldehyde substrates to their corresponding carboxylic acids. Over the last decades, ALDHs have been the subject of several studies as it was revealed that their differential expression patterns in various cancer types are associated either with carcinogenesis or promotion of cell survival. Here, we attempt to provide a thorough review of hALDHs' diverse functions and 3D structures with particular emphasis on their role in cancer pathology and resistance to chemotherapy. We are especially interested in findings regarding the association of structural features and their changes with effects on enzymes' functionalities. Moreover, we provide an updated outline of the hALDHs inhibitors utilized in experimental or clinical settings for cancer therapy. Overall, this review aims to provide a better understanding of the impact of ALDHs in cancer pathology and therapy from a structural perspective.

Introducing novel key genes and transcription factors associated with rectal cancer response to chemoradiation through co-expression network analysis

Preoperative radiochemotherapy is a promising therapeutic method for locally advanced rectal cancer patients. However, the response of colorectal cancer (CRC) patients to preoperative radiotherapy varies widely. In this study, we aimed to identify novel biomarkers that could predict the response of colorectal tumors to treatment using a systems biology approach. We applied the Weighted Gene Co-Expression Network Analysis to construct co-expression networks and evaluated the correlation of these networks with radiation using the module-trait relationship. We then identified hub genes and related transcription factors in the selected co-expression module. Our analysis of seven constructed modules revealed that one module, which contained 113 nodes and 6066 edges, had the strongest correlation with radiation effects on CRC (correlation = 0.85; p-value = 6e-7). By analyzing the selected module with the CytoHubba plugin, we identified four hub genes, including ZEB2, JAM2, NDN, and PPAP2A. We also identified seven important transcription factors, including KLF4, SUZ12, TCF4, NANOG, POU5F1, SOX2, and SMARCA4, which may play essential roles in regulating the four hub genes. In summary, our findings suggest that ZEB2, JAM2, NDN, and PPAP2A, along with the seven transcription factors related to these hub genes, may be associated with the response of colorectal tumors to chemoradiotherapy.

Psychological distress influences lung cancer: Advances and perspectives on the immune system and immunotherapy

Lung cancer has the highest incidence rate and mortality worldwide. Moreover, multiple factors may cause heterogeneity in the efficacy of immunotherapy for lung cancer, and preclinical studies have gradually uncovered the promotive effects of psychological distress (PD) on tumor hallmarks. Therefore, treatment targeted at PD may be a vital factor in adjusting and improving immunotherapy for lung cancer. Here, by focusing on the central nervous system, as well as stress-related crucial neurotransmitters and hormones, we highlight the effects of PD on the lung immune system, the lung tumor microenvironment (TME) and immunotherapy, which brings a practicable means and psychosocial perspective to lung cancer treatment.

Molecular Mechanisms of Tumor Cell Stemness Modulation during Formation of Spheroids

Cancer stem cells (CSCs), their properties and interaction with microenvironment are of interest in modern medicine and biology. There are many studies on the emergence of CSCs and their involvement in tumor pathogenesis. The most important property inherent to CSCs is their stemness. Stemness combines ability of the cell to maintain its pluripotency, give rise to differentiated cells, and interact with environment to maintain a balance between dormancy, proliferation, and regeneration. While adult stem cells exhibit these properties by participating in tissue homeostasis, CSCs behave as their malignant equivalents. High tumor resistance to therapy, ability to differentiate, activate angiogenesis and metastasis arise precisely due to the stemness of CSCs. These cells can be used as a target for therapy of different types of cancer. Laboratory models are needed to study cancer biology and find new therapeutic strategies. A promising direction is three-dimensional tumor models or spheroids. Such models exhibit properties resembling stemness in a natural tumor. By modifying spheroids, it becomes possible to investigate the effect of therapy on CSCs, thus contributing to the development of anti-tumor drug test systems. The review examines the niche of CSCs, the possibility of their study using three-dimensional spheroids, and existing markers for assessing stemness of CSCs.

Targeting aldehyde dehydrogenase enzymes in combination with chemotherapy and immunotherapy: An approach to tackle resistance in cancer cells

Modern cancer chemotherapy originated in the 1940s, and since then, many chemotherapeutic agents have been developed. However, most of these agents show limited response in patients due to innate and acquired resistance to therapy, which leads to the development of multi-drug resistance to different treatment modalities, leading to cancer recurrence and, eventually, patient death. One of the crucial players in inducing chemotherapy resistance is the aldehyde dehydrogenase (ALDH) enzyme. ALDH is overexpressed in chemotherapy-resistant cancer cells, which detoxifies the generated toxic aldehydes from chemotherapy, preventing the formation of reactive oxygen species and, thus, inhibiting the induction of oxidative stress and the stimulation of DNA damage and cell death. This review discusses the mechanisms of chemotherapy resistance in cancer cells promoted by ALDH. In addition, we provide detailed insight into the role of ALDH in cancer stemness, metastasis, metabolism, and cell death. Several studies investigated targeting ALDH in combination with other treatments as a potential therapeutic regimen to overcome resistance. We also highlight novel approaches in ALDH inhibition, including the potential synergistic employment of ALDH inhibitors in combination with chemotherapy or immunotherapy against different cancers, including head and neck, colorectal, breast, lung, and liver.

Innovative nanotheranostics: Smart nanoparticles based approach to overcome breast cancer stem cells mediated chemo- and radioresistances

The alarming increase in the number of breast cancer patients worldwide and the increasing death rate indicate that the traditional and current medicines are insufficient to fight against it. The onset of chemo- and radioresistances and cancer stem cell-based recurrence make this problem harder, and this hour needs a novel treatment approach. Competent nanoparticle-based accurate drug delivery and cancer nanotheranostics like photothermal therapy, photodynamic therapy, chemodynamic therapy, and sonodynamic therapy can be the key to solving this problem due to their unique characteristics. These innovative formulations can be a better cargo with fewer side effects than the standard chemotherapy and can eliminate the stability problems associated with cancer immunotherapy. The nanotheranostic systems can kill the tumor cells and the resistant breast cancer stem cells by novel mechanisms like local hyperthermia and reactive oxygen species and prevent tumor recurrence. These theranostic systems can also combine with chemotherapy or immunotherapy approaches. These combining approaches can be the future of anticancer therapy, especially to overcome the breast cancer stem cells mediated chemo- and radioresistances. This review paper discusses several novel theranostic systems and smart nanoparticles, their mechanism of action, and their modifications with time. It explains their relevance and market scope in the current era. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

ALDH1: A potential therapeutic target for cancer stem cells in solid tumors

Solid tumors can be divided into benign solid tumors and solid malignant tumors in the academic community, among which malignant solid tumors are called cancers. Cancer is the second leading cause of death in the world, and the global incidence of cancer is increasing yearly New cancer patients in China are always the first. After the concept of stem cells was introduced in the tumor community, the CSC markers represented by ALDH1 have been widely studied due to their strong CSC cell characteristics and potential to be the driving force of tumor metastasis. In the research results in the past five years, it has been found that ALDH1 is highly expressed in various solid cancers such as breast cancer, lung cancer, colorectal cancer, liver cancer, gastric cancer, cervical cancer, esophageal cancer, ovarian cancer, head,and neck cancer. ALDH1 can activate and transform various pathways (such as the USP28/MYC signaling pathway, ALDH1A1/HIF-1α/VEGF axis, wnt/β-catenin signaling pathway), as well as change the intracellular pH value to promote formation and maintenance, resulting in drug resistance in tumors. By targeting and inhibiting ALDH1 in tumor stem cells, it can enhance the sensitivity of drugs and inhibit the proliferation, differentiation, and metastasis of solid tumor stem cells to some extent. This review discusses the relationship and pathway of ALDH1 with various solid tumors. It proposes that ALDH1 may serve as a diagnosis and therapeutic target for CSC, providing new insights and new strategies for reliable tumor treatment.

Intrinsic and Extrinsic Factors Impacting Cancer Stemness and Tumor Progression

Tumor heterogeneity represents an important limitation to the development of effective cancer therapies. The presence of cancer stem cells (CSCs) and their differentiation hierarchies contribute to cancer complexity and confer tumors the ability to grow, resist treatment, survive unfavorable conditions, and invade neighboring and distant tissues. A large body of research is currently focusing on understanding the properties of CSCs, including their cellular and molecular origin, as well as their biological behavior in different tumor types. In turn, this knowledge informs strategies for targeting these tumor initiating cells and related cancer stemness. Cancer stemness is modulated by the tumor microenvironment, which influences CSC function and survival. Several advanced in vitro models are currently being developed to study cancer stemness in order to advance new knowledge of the key molecular pathways involved in CSC self-renewal and dormancy, as well as to mimic the complexity of patients' tumors in pre-clinical drug testing. In this review, we discuss CSCs and the modulation of cancer stemness by the tumor microenvironment, stemness factors and signaling pathways. In addition, we introduce current models that allow the study of CSCs for the development of new targeted therapies.

3D Breast Tumor Models for Radiobiology Applications

Breast cancer is a leading cause of cancer-associated death in women. The clinical management of breast cancers is normally carried out using a combination of chemotherapy, surgery and radiation therapy. The majority of research investigating breast cancer therapy until now has mainly utilized two-dimensional (2D) in vitro cultures or murine models of disease. However, there has been significant uptake of three-dimensional (3D) in vitro models by cancer researchers over the past decade, highlighting a complimentary model for studies of radiotherapy, especially in conjunction with chemotherapy. In this review, we underline the effects of radiation therapy on normal and malignant breast cells and tissues, and explore the emerging opportunities that pre-clinical 3D models offer in improving our understanding of this treatment modality.

Nanog, in Cooperation with AP1, Increases the Expression of E6/E7 Oncogenes from HPV Types 16/18

Persistent infections with some types of human papillomavirus (HPV) constitute the major etiological factor for cervical cancer development. Nanog, a stem cell transcription factor has been shown to increase during cancer progression. We wanted to determine whether Nanog could modulate transcription of E6 and E7 oncogenes. We used luciferase reporters under the regulation of the long control region (LCR) of HPV types 16 and 18 (HPV16/18) and performed RT-qPCR. We found that Nanog increases activity of both viral regulatory regions and elevates endogenous E6/E7 mRNA levels in cervical cancer-derived cells. We demonstrated by in vitro mutagenesis that changes at Nanog-binding sites found in the HPV18 LCR significantly inhibit transcriptional activation. Chromatin immunoprecipitation (ChIP) assays showed that Nanog binds in vivo to the HPV18 LCR, and its overexpression increases its binding as well as that of c-Jun. Surprisingly, we observed that mutation of AP1-binding sites also affect Nanog's ability to activate transcription, suggesting cooperation between the two factors. We searched for putative Nanog-binding sites in the LCR of several HPVs and surprisingly found them only in those types associated with cancer development. Our study shows, for the first time, a role for Nanog in the regulation of E6/E7 transcription of HPV16/18.

Knockdown of the prognostic cancer stem cell marker Musashi-1 decreases radio-resistance while enhancing apoptosis in hormone receptor-positive breast cancer cells via p21WAF1/CIP1

Purpose

While the stem cell marker Musashi-1 (MSI-1) has been identified as a key player in a wide array of malignancies, few findings exist on its prognostic relevance and relevance for cancer cell death and therapy resistance in breast cancer.

Methods

First, we determined prognostic relevance of MSI-1 in database analyses regarding multiple survival outcomes. To substantiate findings, MSI-1 was artificially downregulated in MCF-7 breast cancer cells and implications for cancer stem cell markers, cell apoptosis and apoptosis regulator p21, proliferation and radiation response were analyzed via flow cytometry and colony formation. Radiation-induced p21 expression changes were investigated using a dataset containing patient samples obtained before and after irradiation and own in vitro experiments.

Results

MSI-1 is a negative prognostic marker for disease-free and distant metastasis-free survival in breast cancer and tends to negatively influence overall survival. MSI-1 knockdown downregulated stem cell gene expression and proliferation, but increased p21 levels and apoptosis. Similar to the MSI-1 knockdown effect, p21 expression was strongly increased after irradiation and was expressed at even higher levels in MSI-1 knockdown cells after irradiation. Finally, combined use of MSI-1 silencing and irradiation reduced cancer cell survival.

Conclusion

MSI-1 is a prognostic marker in breast cancer. MSI-1 silencing downregulates proliferation while increasing apoptosis. The anti-proliferation mediator p21 was upregulated independently after both MSI-1 knockdown and irradiation and even more after both treatments combined, suggesting synergistic potential. Radio-sensitization effects after combining radiation and MSI-1 knockdown underline the potential of MSI-1 as a therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03743-y.

RBM5-AS1 promotes radioresistance in medulloblastoma through stabilization of SIRT6 protein

Cancer stem cells (CSCs) contribute to radioresistance in medulloblastoma. Thus, identification of key regulators of medulloblastoma stemness is critical for improving radiotherapy for medulloblastoma. In the present study, we profiled CSC-related long non-coding RNAs (lncRNAs) between radioresistant and parental medulloblastoma cells. The roles of the lncRNA RBM5-AS1 in the stemness and radiosensitivity of medulloblastoma cells were investigated. We found that RBM5-AS1, a novel inducer of medulloblastoma stemness, was significantly upregulated in radioresistant medulloblastoma cells compared to parental cells. Knockdown of RBM5-AS1 diminished the viability and clonogenic survival of both radioresistant and parental medulloblastoma cells after radiation. Silencing of RBM5-AS1 significantly enhanced radiation-induced apoptosis and DNA damage. In vivo studies confirmed that depletion of RBM5-AS1 inhibited tumor growth and increased radiosensitivity in a medulloblastoma xenograft model. In contrast, overexpression of RBM5-AS1 reduced radiation-induced apoptosis and DNA damage in medulloblastoma cells. Mechanistically, RBM5-AS1 interacted with and stabilized sirtuin 6 (SIRT6) protein. Silencing of SIRT6 reduced the stemness and reinforced radiation-induced DNA damage in medulloblastoma cells. Overexpression of SIRT6 rescued medulloblastoma cells from RBM5-AS1 depletion-induced radiosensitization and DNA damage. Overall, we identify RBM5-AS1 as an inducer of stemness and radioresistance in medulloblastoma. Targeting RBM5-AS1 may represent a potential strategy to overcome the resistance to radiotherapy in this malignancy.

Cancer stem cells, epithelial-mesenchymal transition, ATP and their roles in drug resistance in cancer

The cancer stem cell (CSC) state and epithelial-mesenchymal transition (EMT) activation are tightly interconnected. Cancer cells that acquire the EMT/CSC phenotype are equipped with adaptive metabolic changes to maintain low reactive oxygen species levels and stemness, enhanced drug transporters, anti-apoptotic machinery and DNA repair system. Factors present in the tumor microenvironment such as hypoxia and the communication with non-cancer stromal cells also promote cancer cells to enter the EMT/CSC state and display related resistance. ATP, particularly the high levels of intratumoral extracellular ATP functioning through both signaling pathways and ATP internalization, induces and regulates EMT and CSC. The three of them work together to enhance drug resistance. New findings in each of these factors will help us explore deeper into mechanisms of drug resistance and suggest new resistance-associated markers and therapeutic targets.

Aldehyde Dehydrogenase, a Therapeutic Target in Chordoma: Analysis in 3D Cellular Models

Chordomas are rare, slow-growing tumors of the axial skeleton. These tumors are locally aggressive and refractory to conventional therapies. Radical surgery and radiation remain the first-line treatments. Despite these aggressive treatments, chordomas often recur and second-line treatment options are limited. The mechanisms underlying chordoma radioresistance remain unknown, although several radioresistant cancer cells have been shown to respond favorably to aldehyde dehydrogenase (ALDH) inhibition. The study of chordoma has been delayed by small patient cohorts and few available models due to the scarcity of these tumors. We thus created cellular 3D models of chordoma by using low-adherence culture systems. Then, we evaluated their radiosensitivity using colony-forming and spheroid size assays. Finally, we determined whether pharmacologically inhibiting ALDH increased their radiosensitivity. We found that 3D cellular models of chordoma (derived from primary, relapse, and metastatic tumors) reproduce the histological and gene expression features of the disease. The metastatic, relapse, and primary spheroids displayed high, medium, and low radioresistance, respectively. Moreover, inhibiting ALDH decreased the radioresistance in all three models.

Targeting cancer stem cells for reversing therapy resistance: mechanism, signaling, and prospective agents

Cancer stem cells (CSCs) show a self-renewal capacity and differentiation potential that contribute to tumor progression and therapy resistance. However, the underlying processes are still unclear. Elucidation of the key hallmarks and resistance mechanisms of CSCs may help improve patient outcomes and reduce relapse by altering therapeutic regimens. Here, we reviewed the identification of CSCs, the intrinsic and extrinsic mechanisms of therapy resistance in CSCs, the signaling pathways of CSCs that mediate treatment failure, and potential CSC-targeting agents in various tumors from the clinical perspective. Targeting the mechanisms and pathways described here might contribute to further drug discovery and therapy.

Metabolic regulation of prostate cancer heterogeneity and plasticity

Metabolic reprogramming is one of the main hallmarks of cancer cells. It refers to the metabolic adaptations of tumor cells in response to nutrient deficiency, microenvironmental insults, and anti-cancer therapies. Metabolic transformation during tumor development plays a critical role in the continued tumor growth and progression and is driven by a complex interplay between the tumor mutational landscape, epigenetic modifications, and microenvironmental influences. Understanding the tumor metabolic vulnerabilities might open novel diagnostic and therapeutic approaches with the potential to improve the efficacy of current tumor treatments. Prostate cancer is a highly heterogeneous disease harboring different mutations and tumor cell phenotypes. While the increase of intra-tumor genetic and epigenetic heterogeneity is associated with tumor progression, less is known about metabolic regulation of prostate cancer cell heterogeneity and plasticity. This review summarizes the central metabolic adaptations in prostate tumors, state-of-the-art technologies for metabolic analysis, and the perspectives for metabolic targeting and diagnostic implications.

A multimodal treatment of carbon ions irradiation, miRNA-34 and mTOR inhibitor specifically control high-grade chondrosarcoma cancer stem cells

BACKGROUND AND PURPOSE

High-grade chondrosarcomas are chemo- and radio-resistant cartilage-forming tumors of bone that often relapse and metastase. Thus, new therapeutic strategies are urgently needed.

MATERIAL AND METHODS

Chondrosarcoma cells (CH-2879) were exposed to carbon-ion irradiation, combined with miR-34 mimic and/or rapamycin administration. The effects of treatment on cancer stem cells, stemness-associated phenotype, radioresistance and tumor-initiating properties were evaluated.

RESULTS

We show that high-grade chondrosarcoma cells contain a population of radioresistant cancer stem cells that can be targeted by a combination of carbon-ion therapy, miR-34 mimic administration and/or rapamycin treatment that triggers FOXO3 and miR-34 over-expression. mTOR inhibition by rapamycin triggered FOXO3 and miR-34, leading to KLF4 repression.

CONCLUSION

Our results show that particle therapy combined with molecular treatments effectively controls cancer stem cells and may overcome treatment resistance of high-grade chondrosarcoma.

Expression patterns and clinical significance of the potential cancer stem cell markers OCT4 and NANOG in colorectal cancer patients

Colorectal cancer (CRC) is one of the most important malignancies and causes of cancer-related deaths worldwide. Cancer stem cell markers identification could be helpful to acquire important prognostic information and develop new treatment regimens. This study aimed to evaluate the expression of OCT4 and NANOG in CRC patients and their clinical significance.

Totally 359 CRC samples were stained for OCT4 and NANOG expression using tissue microarray. The correlation between their expression and clinical and pathological features was explored.

The majority of CRC cases showed low-level expression of OCT4 (80%) and NANOG (75%). Lower expression of OCT4 was more often detected in CRC cases with no vascular involvement (P = .01). Also, a trend found between low level of OCT4 expression and absence of distant metastasis or lymph node involvement (P = .07 and P = .09, respectively). Surprisingly, a significant positive correlation was observed between NANOG expression and cellular differentiation (P = .05). Our combined analysis demonstrated that OCT4 ^low/NANOG ^low phenotype has frequently seen in colorectal cancer cases with no vascular invasion (P = .05).

Our observations indicated that higher expression of OCT4 and NANOG can confer malignant and aggressive behavior to CRC. Evaluation of the co-expression of these cancer stem cell markers can serve a new diagnostic and prognostic approach in CRC patients. These findings also suggested that simultaneous expression of OCT4 and NANOG can be considered as a therapeutic marker for targeted therapy of CRC, especially in advanced stages.

Hypoxia promotes proliferation of pituitary adenomas by HIF-1α/ALKBH5 signaling in vitro

Hypoxia is a common phenomenon in pituitary adenomas (PAs). The role and mechanism of hypoxia in the PAs remains elusive. This work aimed to explore the effect of hypoxia on PAs in vitro. PA cells GT1-1 were cultured and treated under hypoxic condition. Cell proliferation assay showed the proliferation of PA cells was increased significantly by hypoxia treatment, with a peak at 12 hours. qPCR and western blot indicated that the expression of HIF-1α, ALKBH5, and Nanog were elevated by hypoxia stimuli. In conclusion, our funding demonstrated that hypoxia could increase Nanog expression through HIF-1α/ALKBH5 signaling, thereby promoting the proliferation of PA cells.