Understanding cancer stem cell heterogeneity and plasticity. Cell Res. 2012;22:457-472. [PMID: 22357481 DOI: 10.1038/cr.2012.13]

Cancer stem cells: Masters of all traits

Cancer is a heterogeneous disease, which contributes to its rapid progression and therapeutic failure. Besides interpatient tumor heterogeneity, tumors within a single patient can present with a heterogeneous mix of genetically and phenotypically distinct subclones. These unique subclones can significantly impact the traits of cancer. With the plasticity that intratumoral heterogeneity provides, cancers can easily adapt to changes in their microenvironment and therapeutic exposure. Indeed, tumor cells dynamically shift between a more differentiated, rapidly proliferating state with limited tumorigenic potential and a cancer stem cell (CSC)-like state that resembles undifferentiated cellular precursors and is associated with high tumorigenicity. In this context, CSCs are functionally located at the apex of the tumor hierarchy, contributing to the initiation, maintenance, and progression of tumors, as they also represent the subpopulation of tumor cells most resistant to conventional anti-cancer therapies. Although the CSC model is well established, it is constantly evolving and being reshaped by advancing knowledge on the roles of CSCs in different cancer types. Here, we review the current evidence of how CSCs play a pivotal role in providing the many traits of aggressive tumors while simultaneously evading immunosurveillance and anti-cancer therapy in several cancer types. We discuss the key traits and characteristics of CSCs to provide updated insights into CSC biology and highlight its implications for therapeutic development and improved treatment of aggressive cancers.

Magnetic Cell Separation Based on Protein Nanoparticles Mediating the Interaction between Magnetic Particles and Target Cells

Isolation of specific cells from biological samples is an important aspect of various biological research and diagnostic applications. Magnetic separation using magnetic particles (MPs) allows for easy and specific isolation of the target cells. However, depending on the target cell antigen, biological ligands, such as antibodies, must be modified or altered on MPs. Additionally, further biological evaluation of isolated cells requires the removal of MPs from cells by the enzymatic degradation of the biological ligands. In this study, we designed a magnetic cell separation system in which temperature-responsive protein nanoparticles mediated the interaction between target cells and MPs, achieving the easy changeability of biological ligands, removal of MPs by cooling, and effective cell isolation. The protein nanoparticles were thermally responsively formed from fusion proteins constituted of elastin-like polypeptide (ELP), poly(aspartic acid) [poly(d)], and proteins-of-interest such as NanoLuc luciferase (Nluc) fused with replication initiation protein (Rep) (ELP-poly(d)-Nluc-Rep) or biotin acceptor peptide (BAP) (ELP-poly(d)-Nluc-BAP). Rep exhibited enzymatic conjugation activity with an optional DNA aptamer to protein nanoparticles. The transmembrane glycoprotein mucin 1 (MUC1)-binding DNA aptamer was conjugated to Rep as a model aptamer. Bioluminescence signals emitted from the Nluc domains were used to analyze the binding abilities. BAP contributed to binding to streptavidin-modified MPs via a biotin-streptavidin interaction. The MUC1-conjugated protein nanoparticles bound to MUC1-positive human breast cancer MCF-7 cells via MUC1 aptamers and streptavidin-conjugated MPs via BAP, leading to magnetic cell separation. The ratio of isolated MCF-7 cells via magnetic separation was 71.3% for the MCF-7 suspension at 1000 cells/1 mL. The MPs bound on recovered MCF-7 cells were removed by cooling at 4 °C to induce the dissociation of protein nanoparticles. Magnetic cell separation systems that use protein nanoparticles are a promising technology for biological research and diagnostic applications.

Adaptive Plasticity Tumor Cells Modulate MAPK-Targeting Therapy Response in Colorectal Cancer

MAPK pathway inhibitors (MAPKi) are increasingly used in the treatment of advanced colorectal cancer, but often produce short-lived responses in patients. Although acquired resistance by de novo mutations in tumors have been found to reduce response in some patients, additional mechanisms underlying the limited response durability of MAPK targeting therapy remain unknown. Here, we denote new contributory tumor biology and provide insight on the impact of tumor plasticity on therapy response. Analysis of MAPKi treated patients revealed activation of stemness programs and increased ASCL2 expression, which are associated with poor outcomes. Greater ASCL2 with MAPKi treatment was also seen in patient-derived CRC models, independent of driver mutations. We find ASCL2 denotes a distinct cell population, arising from phenotypic plasticity, with a proliferative, stem-like phenotype, and decreased sensitivity to MAPKi therapy, which were named adaptive plasticity tumor (APT) cells. MAPK pathway suppression induces the APT phenotype in cells, resulting in APT cell enrichment in tumors and limiting therapy response in preclinical and clinical data. APT cell depletion improved MAPKi treatment efficacy and extended MAPKi response durability in mice. These findings uncover a cellular program that mitigates the impact of MAPKi therapies and highlights the importance of addressing tumor plasticity to improve clinical outcomes.

Revisiting ABC Transporters and Their Clinical Significance in Glioblastoma

Background: The multiple drug-resistant phenomenon has long since plagued the effectiveness of various chemotherapies used in the treatment of patients with glioblastoma (GBM), which is still incurable to this day. ATP-binding cassette (ABC) transporters function as drug transporters and have been touted to be the main culprits in developing resistance to xenobiotic drugs in GBM. Methods: This review systematically analyzed the efficacy of ABC transporters against various anticancer drugs from 16 studies identified from five databases (PubMed, Medline, Embase, Scopus, and ScienceDirect). Results: Inhibition of ABC transporters, especially ABCB1, improved drug efficacies. Staple GBM phenotypes, such as GBM stem cells and increased activation of the PI3K/Akt/NF-κB pathway, have been implicated in the expression of several ABC transporters. Using the datasets in The Cancer Genome Atlas and Gene Expression Omnibus, we found upregulated ABC transporters that either negatively impacted survival in univariate analyses (ABCA1, ABCA13, ABCB9, ABCD4) or were independent negative prognosis factors for patients with GBM (ABCA13, ABCB9). Our multivariate analysis further demonstrated three ABC transporters, ABCA13 (Hazard Ratio (HR) = 1.31, p = 0.017), ABCB9 (HR = 1.26, p = 0.03), and ABCB5 (HR = 0.77, p = 0.016), with the administration of alkylating agents (HR = 0.41, p < 0.001), were independent negative prognosis factors for patients with GBM. Conclusions: These findings reinforce the important role played by ABC transporters, particularly by ABCA13, ABCB9, and ABCB1, which could be potential targets that warrant further evaluations for alternate strategies to augment the effects of existing alkylating agents and xenobiotic drugs.

Adenosinergic Signalling in Cervical Cancer Microenvironment

Despite the emergence of the first human papillomavirus vaccine, the incidence of cervical cancer is still responsible for more than 350,000 deaths yearly. Over the past decade, ecto-5'-nucleotidase (CD73/5'-NT) and extracellular adenosine (ADO) signalling has been the subject of many investigations to target cancer progression. In general, the adenosinergic axis has been linked to tumourigenic effects. However, CD73 can play contradictory effects, probably dependent on the tumour type, tumour microenvironment and tumour stage, thus being in some circumstances, inversely related to tumour progression. We herein reviewed the pathophysiological function of CD73 in cervical cancer and performed in silico analysis of the main components of the adenosinergic signalling in human tissues of cervical cancer compared to non-tumour cervix tissue. Our data showed that the NT5E gene, that encoded CD73, is hypermethylated, leading to a decreased CD73 expression in cervical cancer cells compared to normal cells. Consequently, the high availability of ADO cytoplasmatic/extracellular leads to its conversion to AMP by ADK, culminating in global hypermethylation. Therefore, epigenetic modulation may reveal a new role for CD73 in cervical cancer.

Deciphering normal and cancer stem cell niches by spatial transcriptomics: opportunities and challenges

Cancer stem cells (CSCs) often exhibit stem-like attributes that depend on an intricate stemness-promoting cellular ecosystem within their niche. The interplay between CSCs and their niche has been implicated in tumor heterogeneity and therapeutic resistance. Normal stem cells (NSCs) and CSCs share stemness features and common microenvironmental components, displaying significant phenotypic and functional plasticity. Investigating these properties across diverse organs during normal development and tumorigenesis is of paramount research interest and translational potential. Advancements in next-generation sequencing (NGS), single-cell transcriptomics, and spatial transcriptomics have ushered in a new era in cancer research, providing high-resolution and comprehensive molecular maps of diseased tissues. Various spatial technologies, with their unique ability to measure the location and molecular profile of a cell within tissue, have enabled studies on intratumoral architecture and cellular cross-talk within the specific niches. Moreover, delineation of spatial patterns for niche-specific properties such as hypoxia, glucose deprivation, and other microenvironmental remodeling are revealed through multilevel spatial sequencing. This tremendous progress in technology has also been paired with the advent of computational tools to mitigate technology-specific bottlenecks. Here we discuss how different spatial technologies are used to identify NSCs and CSCs, as well as their associated niches. Additionally, by exploring related public data sets, we review the current challenges in characterizing such niches, which are often hindered by technological limitations, and the computational solutions used to address them.

Comprehensive review of drug resistance in mammalian cancer stem cells: implications for cancer therapy

Cancer remains a significant global challenge, and despite the numerous strategies developed to advance cancer therapy, an effective cure for metastatic cancer remains elusive. A major hurdle in treatment success is the ability of cancer cells, particularly cancer stem cells (CSCs), to resist therapy. These CSCs possess unique abilities, including self-renewal, differentiation, and repair, which drive tumor progression and chemotherapy resistance. The resilience of CSCs is linked to certain signaling pathways. Tumors with pathway-dependent CSCs often develop genetic resistance, whereas those with pathway-independent CSCs undergo epigenetic changes that affect gene regulation. CSCs can evade cytotoxic drugs, radiation, and apoptosis by increasing drug efflux transporter activity and activating survival mechanisms. Future research should prioritize the identification of new biomarkers and signaling molecules to better understand drug resistance. The use of cutting-edge approaches, such as bioinformatics, genomics, proteomics, and nanotechnology, offers potential solutions to this challenge. Key strategies include developing targeted therapies, employing nanocarriers for precise drug delivery, and focusing on CSC-targeted pathways such as the Wnt, Notch, and Hedgehog pathways. Additionally, investigating multitarget inhibitors, immunotherapy, and nanodrug delivery systems is critical for overcoming drug resistance in cancer cells.

MetaPhenotype: A Transferable Meta-Learning Model for Single-Cell Mass Spectrometry-Based Cell Phenotype Prediction Using Limited Number of Cells

Single-cell mass spectrometry (SCMS) is an emerging tool for studying cell heterogeneity according to variation of molecular species in single cells. Although it has become increasingly common to employ machine learning models in SCMS data analysis, such as the classification of cell phenotypes, the existing machine learning models often suffer from low adaptability and transferability. In addition, SCMS studies of rare cells can be restricted by limited number of cell samples. To overcome these limitations, we performed SCMS analyses of melanoma cancer cell lines with two phenotypes (i.e., primary and metastatic cells). We then developed a meta-learning-based model, MetaPhenotype, that can be trained using a small amount of SCMS data to accurately classify cells into primary or metastatic phenotypes. Our results show that compared with standard transfer learning models, MetaPhenotype can rapidly predict and achieve a high accuracy of over 90% with fewer new training samples. Overall, our work opens the possibility of accurate cell phenotype classification based on fewer SCMS samples, thus lowering the demand for sample acquisition.

Targeting Hepatic Cancer Stem Cells (CSCs) and Related Drug Resistance by Small Interfering RNA (siRNA)

Tumor recurrence after curative therapy and hepatocellular carcinoma (HCC) cells' resistance to conventional therapies is the reasons for the worse clinical results of HCC patients. A tiny population of cancer cells with a strong potential for self-renewal, differentiation, and tumorigenesis has been identified as cancer stem cells (CSCs). The discovery of CSC surface markers and the separation of CSC subpopulations from HCC cells have been made possible by recent developments in the study of hepatic (liver) CSCs. Hepatic CSC surface markers include epithelial cell adhesion molecules (EpCAM), CD133, CD90, CD13, CD44, OV-6, ALDH, and K19. CSCs have a significant influence on the development of cancer, invasiveness, self-renewal, metastasis, and drug resistance in HCC, and thus provide a therapeutic chance to treat HCC and avoid its recurrence. Therefore, it is essential to develop treatment approaches that specifically and effectively target hepatic stem cells. Given this, one potential treatment approach is to use particular small interfering RNA (siRNA) to target CSC, disrupting their behavior and microenvironment as well as changing their epigenetic state. The characteristics of CSCs in HCC are outlined in this study, along with new treatment approaches based on siRNA that may be used to target hepatic CSCs and overcome HCC resistance to traditional therapies.

Joint representation and visualization of derailed cell states with Decipher

Biological insights often depend on comparing conditions such as disease and health, yet we lack effective computational tools for integrating single-cell genomics data across conditions or characterizing transitions from normal to deviant cell states. Here, we present Decipher, a deep generative model that characterizes derailed cell-state trajectories. Decipher jointly models and visualizes gene expression and cell state from normal and perturbed single-cell RNA-seq data, revealing shared and disrupted dynamics. We demonstrate its superior performance across diverse contexts, including in pancreatitis with oncogene mutation, acute myeloid leukemia, and gastric cancer.

Metabolomics-driven approaches for identifying therapeutic targets in drug discovery

Identification of therapeutic targets can directly elucidate the mechanism and effect of drug therapy, which is a central step in drug development. The disconnect between protein targets and phenotypes under complex mechanisms hampers comprehensive target understanding. Metabolomics, as a systems biology tool that captures phenotypic changes induced by exogenous compounds, has emerged as a valuable approach for target identification. A comprehensive overview was provided in this review to illustrate the principles and advantages of metabolomics, delving into the application of metabolomics in target identification. This review outlines various metabolomics-based methods, such as dose-response metabolomics, stable isotope-resolved metabolomics, and multiomics, which identify key enzymes and metabolic pathways affected by exogenous substances through dose-dependent metabolite-drug interactions. Emerging techniques, including single-cell metabolomics, artificial intelligence, and mass spectrometry imaging, are also explored for their potential to enhance target discovery. The review emphasizes metabolomics' critical role in advancing our understanding of disease mechanisms and accelerating targeted drug development, while acknowledging current challenges in the field.

A live single-cell reporter system reveals drug-induced plasticity of a cancer stem cell-like population in cholangiocarcinoma

Cancer stem cells (CSC) play an important role in carcinogenesis and are acknowledged to be responsible for chemoresistance in cholangiocarcinoma (CCA). Studying CCA CSC has been challenging, due to lack of consensus CSC markers, and to their plastic nature. Since dual expression of the core pluripotent factors SOX2/OCT4 has been shown to correlate with poor outcome in CCA patients, we selected the SOX2/OCT4 activating short half-life GFP-based live reporter (SORE6-dsCopGFP) to study CSC dynamics at the single-cell level. Transduction of five human CCA cell lines resulted in the expression of 1.8-13.1% GFP-positive (SORE6POS) cells. By live imaging, we found that SORE6POS CCA cells possess self-renewal capacity and that they can be induced to differentiate. Significantly, the SORE6POS cells were highly tumorigenic, both in vitro and in vivo, thus implicating the characteristics of primary CSCs. When we then analyzed for selected CSC-related markers, we found that the majority of both CD133+/CD44+, and CD133+/LGR5+ CCA cells were SORE6POS cells. Exposing transduced cells to standard CCA chemotherapy revealed higher growth rate inhibition at 50% (GR50s) for SORE6POS cells compared to GFP-negative (SORE6NEG) ones indicating that these CSC-like cells were more resistant to the treatment. Moreover, the chemotherapy induced SORE6POS from SORE6NEG cells, while retaining the existing SORE6POS population. Finally, treatment of transduced cells with CDK4/6 inhibitors in vitro for 3 days resulted in a lowered CSC number in the culture. Thus, applying a live reporter system allowed us to elucidate the stem cell diversity and drug-induced plasticity of CCA CSCs. These findings have clear implications for future management of such patients.

Targeting cellular plasticity: esculetin-driven reversion of stem cell-like characteristics and EMT phenotype in transforming cells with sequential p53/p73 knockdowns

The intricate interplay of cancer stem cell plasticity, along with the bidirectional transformation between epithelial-mesenchymal states, introduces further intricacy to offer insights into newer therapeutic approaches. Differentiation therapy, while successful in targeting leukemic stem cells, has shown limited overall success, with only a few promising instances. Using colon carcinoma cell strains with sequential p53/p73 knockdowns, our study underscores the association between p53/p73 and the maintenance of cellular plasticity. Morphological alterations corresponding with cell surface marker expressions, transcriptome analysis and functional assays were performed to access stemness and EMT (Epithelial-Mesenchymal Transition) characteristics in the spectrum of cells exhibiting sequential p53 and p73 knockdowns. Notably, our investigation explores the effectiveness of esculetin in reversing the shift from an epithelial to a mesenchymal phenotype, characterized by stem cell-like traits. Esculetin significantly induces enterocyte differentiation and promotes epithelial cell polarity by altering Wnt axes in Cancer Stem Cell-like cells characterized by high mesenchymal features. These results align with our previous findings in leukemic blast cells, establishing esculetin as an effective differentiating agent in both Acute Myeloid Leukemia (AML) and solid tumor cells.

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.

Exosomal misfolded proteins released by cancer stem cells: dual functions in balancing protein homeostasis and orchestrating tumor progression

Cancer stem cells (CSCs), the master regulators of tumor heterogeneity and progression, exert profound influence on cancer metastasis, via various secretory vesicles. Emerging from CSCs, the exosomes serve as pivotal mediators of intercellular communication within the tumor microenvironment, modulating invasion, angiogenesis, and immune responses. Moreover, CSC-derived exosomes play a central role in sculpting a dynamic landscape, contributing to the malignant phenotype. Amidst several exosomal cargoes, misfolded proteins have recently gained attention for their dual functions in maintaining protein homeostasis and promoting tumor progression. Disrupting these communication pathways could potentially prevent the maintenance and expansion of CSCs, overcome treatment resistance, and inhibit the supportive environment created by the tumor microenvironment, thereby improving the effectiveness of cancer therapies and reducing the risk of tumor recurrence and metastasis. Additionally, exosomes have also shown potential therapeutic applications, such as in drug delivery or as biomarkers for cancer diagnosis and prognosis. Therefore, comprehending the biology of exosomes derived from CSCs is a multifaceted area of research with implications in both basic sciences and clinical applications. This review explores the intricate interplay between exosomal misfolded proteins released by CSCs, the potent contributor in tumor heterogeneity, and their impact on cellular processes, shedding light on their role in cancer progression.

Dendritic cells pulsed with penetratin-OLFM4 inhibit the growth and metastasis of melanoma in mice

Cancer stem cells (CSCs) can self-renew and differentiate, contributing to tumor heterogeneity, metastasis, and recurrence. Their resistance to therapies, including immunotherapy, underscores the importance of targeting them for complete remission and relapse prevention. Olfactomedin 4 (OLFM4), a marker associated with various cancers such as colorectal cancer, is expressed on CSCs promoting immune evasion and tumorigenesis. However, its potential as a target for CSC-specific immunotherapy remains underexplored. The primary aim of this study is to evaluate the effectiveness of targeting OLFM4 with dendritic cell (DC)-based vaccines in inhibiting tumor growth and metastasis. To improve antigen delivery and immune response, OLFM4 was conjugated with a protein-transduction domain (PTD) from the antennapedia of Drosophila called penetratin, creating a fusion protein (P-OLFM4). The efficacy of DCs pulsed with P-OLFM4 (DCs [P-OLFM4]) was compared to DCs pulsed with OLFM4 (DCs [OLFM4]) and PBS (DCs [PBS]). DCs [P-OLFM4] inhibited tumor growth by 91.2 % and significantly reduced lung metastasis of OLFM4+ melanoma cells by 97 %, compared to the DCs [PBS]. DCs [OLFM4] also demonstrated a reduction in lung metastasis by 59.7 % compared to DCs [PBS]. Immunization with DCs [P-OLFM4] enhanced OLFM4-specific T-cell proliferation, interferon-γ production, and cytotoxic T cell activity in mice. The results indicate that OLFM4 is a viable target for CSC-focused immunotherapy. DC [P-OLFM4] vaccines can elicit robust immune responses, significantly inhibiting tumor growth and metastasis. This strategy holds promise for developing more effective cancer treatments that specifically target CSCs, potentially leading to better patient outcomes by reducing the likelihood of tumor relapse and metastasis.

Advances in Single-Cell Techniques for Linking Phenotypes to Genotypes

Single-cell analysis has become an essential tool in modern biological research, providing unprecedented insights into cellular behavior and heterogeneity. By examining individual cells, this approach surpasses conventional population-based methods, revealing critical variations in cellular states, responses to environmental cues, and molecular signatures. In the context of cancer, with its diverse cell populations, single-cell analysis is critical for investigating tumor evolution, metastasis, and therapy resistance. Understanding the phenotype-genotype relationship at the single-cell level is crucial for deciphering the molecular mechanisms driving tumor development and progression. This review highlights innovative strategies for selective cell isolation based on desired phenotypes, including robotic aspiration, laser detachment, microraft arrays, optical traps, and droplet-based microfluidic systems. These advanced tools facilitate high-throughput single-cell phenotypic analysis and sorting, enabling the identification and characterization of specific cell subsets, thereby advancing therapeutic innovations in cancer and other diseases.

Manipulating Redox Homeostasis of Cancer Stem Cells Overcome Chemotherapeutic Resistance through Photoactivatable Biomimetic Nanodiscs

Tumor heterogeneity remains a significant obstacle in cancer therapy due to diverse cells with varying treatment responses. Cancer stem-like cells (CSCs) contribute significantly to intratumor heterogeneity, characterized by high tumorigenicity and chemoresistance. CSCs reside in the depth of the tumor, possessing low reactive oxygen species (ROS) levels and robust antioxidant defense systems to maintain self-renewal and stemness. A nanotherapeutic strategy is developed using tumor-penetrating peptide iRGD-modified high-density lipoprotein (HDL)-mimetic nanodiscs (IPCND) that ingeniously loaded with pyropheophorbide-a (Ppa), bis (2-hydroxyethyl) disulfide (S-S), and camptothecin (CPT) by synthesizing two amphiphilic drug-conjugated sphingomyelin derivatives. Photoactivatable Ppa can generate massive ROS which as intracellular signaling molecules effectively shut down self-renewal and trigger differentiation of the CSCs, while S-S is utilized to deplete GSH and sustainably imbalance redox homeostasis by reducing ROS clearance. Simultaneously, the depletion of GSH is accompanied by the release of CPT, which leads to subsequent cell death. This dual strategy successfully disturbed the redox equilibrium of CSCs, prompting their differentiation and boosting the ability of CPT to kill CSCs upon laser irradiation. Additionally, it demonstrated a synergistic anti-cancer effect by concurrently eliminating therapeutically resistant CSCs and bulk tumor cells, effectively suppressing tumor growth in CSC-enriched heterogeneous colon tumor mouse models.

Double-Layered Hollow Mesoporous Cuprous Oxide Nanoparticles for Double Drug Sequential Therapy of Tumors

Cancer stem cells (CSCs) are one of the determinants of tumor heterogeneity and are characterized by self-renewal, high tumorigenicity, invasiveness, and resistance to various therapies. To overcome the resistance of traditional tumor therapies resulting from CSCs, a strategy of double drug sequential therapy (DDST) for CSC-enriched tumors is proposed in this study and is realized utilizing the developed double-layered hollow mesoporous cuprous oxide nanoparticles (DL-HMCONs). The high drug-loading contents of camptothecin (CPT) and all-trans retinoic acid (ATRA) demonstrate that the DL-HMCON can be used as a generic drug delivery system. ATRA and CPT can be sequentially loaded in and released from CPT3@ATRA3@DL-HMCON@HA. The DDST mechanisms of CPT3@ATRA3@DL-HMCON@HA for CSC-containing tumors are demonstrated as follows: 1) the first release of ATRA from the outer layer induces differentiation from CSCs with high drug resistance to non-CSCs with low drug resistance; 2) the second release of CPT from the inner layer causes apoptosis of non-CSCs; and 3) the third release of Cu+ from DL-HMCON itself triggers the Fenton-like reaction and glutathione depletion, resulting in ferroptosis of non-CSCs. This CPT3@ATRA3@DL-HMCON@HA is verified to possess high DDST efficacy for CSC-enriched tumors with high biosafety.

Tanreqing injection inhibits stemness and enhances sensitivity of non-small cell lung cancer models to gefitinib through ROS/STAT3 signaling pathway

Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has emerged as a significant obstacle in managing patients with EGFR-mutant non-small-cell lung cancer (NSCLC), necessitating the exploration of novel therapeutic approaches. Tanreqing injection (TRQ) is a kind of Chinese patent medicine known for its heat-clearing and detoxifying properties. Studies have shown a correlation between tumor drug resistance and enrichment of cancer stem cells (CSCs). We aim to investigate the feasibility of TRQ enhancing sensitivity to gefitinib by targeting CSCs and reactive oxygen species (ROS). In our study, TRQ significantly inhibited cell proliferation in gefitinib-resistant non-small-cell lung cancer (NSCLC) models including 2D cell lines, 3D cell spheres, tumor-bearing animal and organoids. Compared with the gefitinib group alone, addition of TRQ elevated ROS levels, attenuated upregulation of the protein levels of sex-determining region Y-box 2 (SOX2) and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) induced by gefitinib treatment, and inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Scavenging ROS could restore tumor stemness, attenuate the inhibitory effect on the phosphorylation of STAT3, and promote cell proliferation. These results suggested that TRQ could enhance sensitivity of NSCLC models to gefitinib, providing a new combined treatment strategy.

The intricate interplay between cancer stem cells and cell-of-origin of cancer: implications for therapeutic strategies

Background

Cancer stem cells (CSCs) have emerged as pivotal players in tumorigenesis, disease progression, and resistance to therapies.

Objective

This comprehensive review delves into the intricate relationship between CSCs and the cell-of-origin in diverse cancer types.

Design

Comprehensive review of thematically-relevant literature.

Methods

We explore the underlying molecular mechanisms that drive the conversion of normal cells into CSCs and the impact of the cell-of-origin on CSC properties, tumor initiation, and therapeutic responses. Moreover, we discuss potential therapeutic interventions targeting CSCs based on their distinct cell-of-origin characteristics.

Results

Accruing evidence suggest that the cell-of-origin, the cell type from which the tumor originates, plays a crucial role in determining the properties of CSCs and their contribution to tumor heterogeneity.

Conclusion

By providing critical insights into the complex interplay between CSCs and their cellular origins, this article aims to enhance our understanding of cancer biology and pave the way for more effective and personalized cancer treatments.

Heterogeneity and molecular landscape of melanoma: implications for targeted therapy

Uveal cancer (UM) offers a complex molecular landscape characterized by substantial heterogeneity, both on the genetic and epigenetic levels. This heterogeneity plays a critical position in shaping the behavior and response to therapy for this uncommon ocular malignancy. Targeted treatments with gene-specific therapeutic molecules may prove useful in overcoming radiation resistance, however, the diverse molecular makeups of UM call for a patient-specific approach in therapy procedures. We need to understand the intricate molecular landscape of UM to develop targeted treatments customized to each patient's specific genetic mutations. One of the promising approaches is using liquid biopsies, such as circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA), for detecting and monitoring the disease at the early stages. These non-invasive methods can help us identify the most effective treatment strategies for each patient. Single-cellular is a brand-new analysis platform that gives treasured insights into diagnosis, prognosis, and remedy. The incorporation of this data with known clinical and genomics information will give a better understanding of the complicated molecular mechanisms that UM diseases exploit. In this review, we focused on the heterogeneity and molecular panorama of UM, and to achieve this goal, the authors conducted an exhaustive literature evaluation spanning 1998 to 2023, using keywords like "uveal melanoma, "heterogeneity". "Targeted therapies"," "CTCs," and "single-cellular analysis".

Transcription factor ZIC2 regulates the tumorigenic phenotypes associated with both bulk and cancer stem cells in epithelial ovarian cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy in North America. Current therapeutic regimens are ineffective against advanced EOC. A better understanding of the molecular mechanisms that regulate the biology of EOC will be a critical step toward developing more efficacious therapies against EOC. Herein, we demonstrate that elevated expression of transcription factor ZIC2 was associated with lower survival of EOC patients. Knockout of endogenous ZIC2 in EOC cells attenuated the tumorigenic phenotypes associated with both bulk and cancer stem cells in vitro and in vivo, indicating a pro-tumorigenic role of ZIC2 in EOC. On the other hand, however, overexpression of ZIC2 in EOC cells that do not express endogenous ZIC2 promoted cell migration and sphere formation, but inhibited cell growth and colony formation in vitro and tumor growth in vivo, indicating that the role for ZIC2 in EOC is context dependent. Our transcriptomic analysis showed that ZIC2-regulated genes were involved in multiple biological processes and signaling pathways associated with tumor progression. In conclusion, our findings reveal a context-dependent role for ZIC2 in regulating tumorigenic phenotypes in EOC, providing evidence that ZIC2 can be a potential therapeutic target for EOCs that express a high level of ZIC2.

Mitochondrial-Stem Cell Connection: Providing Additional Explanations for Understanding Cancer

The cancer paradigm is generally based on the somatic mutation model, asserting that cancer is a disease of genetic origin. The mitochondrial-stem cell connection (MSCC) proposes that tumorigenesis may result from an alteration of the mitochondria, specifically a chronic oxidative phosphorylation (OxPhos) insufficiency in stem cells, which forms cancer stem cells (CSCs) and leads to malignancy. Reviewed evidence suggests that the MSCC could provide a comprehensive understanding of all the different stages of cancer. The metabolism of cancer cells is altered (OxPhos insufficiency) and must be compensated by using the glycolysis and the glutaminolysis pathways, which are essential to their growth. The altered mitochondria regulate the tumor microenvironment, which is also necessary for cancer evolution. Therefore, the MSCC could help improve our understanding of tumorigenesis, metastases, the efficiency of standard treatments, and relapses.

Flavonostilbenes natural hybrids from Rhamnoneuron balansae as potential antitumors targeting ALDH1A1: molecular docking, ADMET, MM-GBSA calculations and molecular dynamics studies

Several studies have linked Cancer stem cells (CSCs) to cancer resistance development to chemotherapy and radiotherapy. ALDH1A1 is a key enzyme that regulates the gene expression of CSCs and creates an immunosuppressive tumor microenvironment. It was reported that quercetin and resveratrol were among the inhibitors of ALDH1A1. In early 2022, it was reported that new 11 flavonostilbenes (rhamnoneuronal D-N) were isolated from Rhamnoneuron balansae as potential antiaging natural products. Rhamnoneuronal H (5) could be envisioned as a natural hybrid of quercetin and resveratrol. It was therefore hypothesized that 5 and its analogous isolates rhamnoneuronal D-G (1-4) and rhamnoneuronal I-N (6-11) would have potential ALDH1A1 inhibitory activity. To this end, all isolates were subjected to molecular docking, MM-GBSA, ADMET, and molecular dynamics simulations studies to assess their potential as new leads for cancer treatment targeting ALDH1A1. In silico findings revealed that natural hybrid 5 has a similar binding affinity, judged by MM-GBSA, to the ALDH1A1 active site when compared to the co-crystalized ligand (-64.71 kcal/mole and -64.12 kcal/mole, respectively). Despite having lesser affinity than that of the co-crystalized ligand, the rest of the flavonostilbenes, except 2-4, displayed better binding affinities (-37.55 kcal/mole to -58.6 kcal/mole) in comparison to either resveratrol (-34.44 kcal/mole) or quercetin (-36.48 kcal/mole). Molecular dynamic simulations showed that the natural hybrids 1, 5-11 are of satisfactory stability up to 100 ns. ADMET outcomes indicate that these hybrids displayed acceptable properties and hence could represent an ideal starting point for the development of potent ALDH1A1 inhibitors for cancer treatment.Communicated by Ramaswamy H. Sarma.

Transgelin-2, a novel cancer stem cell-related biomarker, is a diagnostic and therapeutic target for biliary tract cancer

BACKGROUND

Biliary tract cancer (BTC) is a relatively rare but aggressive gastrointestinal cancer with a high mortality rate. Cancer stem cell (CSC) populations play crucial roles in tumor biology and are responsible for the low response to anti-cancer treatment and the high recurrence rate. This study investigated the role of Transgelin-2 (TAGLN2), overexpressed in CSC in BTC cells, and analyzed its expression in patient tissues and serum to identify potential new targets for BTC.

METHODS

TAGLN2 expression was suppressed by small-interfering or short hairpin RNAs, and its effects on tumor biology were assessed in several BTC cell lines. Furthermore, the effects of TAGLN2 silencing on gemcitabine-resistant BTC cells, differentially expressed genes, proteins, and sensitivity to therapeutics or radiation were assessed. TAGLN2 expression was also assessed using western blotting and immunohistochemistry in samples obtained from patients with BTC to validate its clinical application.

RESULTS

Suppression of TAGLN2 in BTC cell lines decreased cell proliferation, migration, invasion, and tumor size, in addition to a reduction in CSC features, including clonogenicity, radioresistance, and chemoresistance. TAGLN2 was highly expressed in BTC tissues, especially in cancer-associated fibroblasts in the stroma. Patients with a low stromal immunohistochemical index had prolonged disease-free survival compared to those with a high stromal immunohistochemical index (11.5 vs. 7.4 months, P = 0.013). TAGLN2 expression was higher in the plasma of patients with BTC than that in those with benign diseases. TAGLN2 had a higher area under the curve (0.901) than CA19-9, a validated tumor biomarker (0.799; P < 0.001).

CONCLUSION

TAGLN2 plays a critical role in promoting BTC cell growth and motility and is involved in regulating BTC stemness. Silencing TAGLN2 expression enhanced cell sensitivity to radiation and chemotherapeutic drugs. The expression of TAGLN2 in patient tissue and plasma suggests its potential to serve as a secretory biomarker for BTC. Overall, targeting TAGLN2 could be an appropriate therapeutic strategy against advanced cancer following chemotherapy failure.

Anti-ENO1 antibody combined with metformin against tumor resistance: a novel antibody-based platform

Background

Antibody-based platforms (i.e., ADC) have emerged as one of the most encouraging tools for the cancer resistance caused by cancer stem cells (CSCs) enrichment. Our study might provide a promising therapeutic direction against drug resistance and serve as a potential precursor platform for screening ADC.

Methods

The cell migration, invasion, drug resistance, and self-renewal were assessed by the cell invasion and migration assay, wound healing assay, CCK-8 assay, colony formation assay, and sphere formation assay, respectively. The expression profiles of CSCs (ALDH+ and CD44+) subpopulations were screened by flow cytometry. The western blot and cell immunofluorescence assay were used to evaluate pathway-related protein expression in both anti-ENO1 antibody, MET combined with DPP/CTX-treated CSCs.

Results

In the present study, western blot and flow cytometry verified that anti-ENO1 antibody target the CD44+ subpopulation by inhibiting the PI3K/AKT pathway, while metformin might target the ALDH+ subpopulation through activation of the AMPK pathway and thus reverse drug resistance to varying degrees. Subsequently, in vitro investigation indicated that anti-ENO1 antibody, metformin combined with cisplatin/cetuximab could simultaneously target ALDH+ and CD44+ subpopulations. The combination also inhibited the CSCs proliferation, migration, invasion, and sphere formation; which may result in overcoming the drug resistance. Then, molecular mechanism exploration verified that the anti-ENO1 antibody, metformin combined with cisplatin/cetuximab inhibited the Wnt/β-catenin signaling.

Conclusions

The study preliminarily revealed anti-ENO1 antibody combined with metformin could overcome drug resistance against CSCs by inhibiting the Wnt//β-catenin pathway and might serve as a potential precursor platform for screening ADC. More importantly, it is reasonably believed that antibody-based drug combination therapy might function as an encouraging tool for oncotherapy.

ImmunoPET imaging of TIGIT in the glioma microenvironment

Glioblastoma (GBM) is the most common primary malignant brain tumor. Currently, there are few effective treatment options for GBM beyond surgery and chemo-radiation, and even with these interventions, median patient survival remains poor. While immune checkpoint inhibitors (ICIs) have demonstrated therapeutic efficacy against non-central nervous system cancers, ICI trials for GBM have typically had poor outcomes. TIGIT is an immune checkpoint receptor that is expressed on activated T-cells and has a role in the suppression of T-cell and Natural Killer (NK) cell function. As TIGIT expression is reported as both prognostic and a biomarker for anti-TIGIT therapy, we constructed a molecular imaging agent, [89Zr]Zr-DFO-anti-TIGIT (89Zr-αTIGIT), to visualize TIGIT in preclinical GBM by immunoPET imaging. PET imaging and biodistribution analysis of 89Zr-αTIGIT demonstrated uptake in the tumor microenvironment of GBM-bearing mice. Blocking antibody and irrelevant antibody tracer studies demonstrated specificity of 89Zr-αTIGIT with significance at a late time point post-tracer injection. However, the magnitude of 89Zr-αTIGIT uptake in tumor, relative to the IgG tracer was minimal. These findings highlight the features and limitations of using 89Zr-αTIGIT to visualize TIGIT in the GBM microenvironment.

Immunotherapeutic IL-6R and targeting the MCT-1/IL-6/CXCL7/PD-L1 circuit prevent relapse and metastasis of triple-negative breast cancer

Rationale: Multiple copies in T-cell malignancy 1 (MCT-1) is a prognostic biomarker for aggressive breast cancers. Overexpressed MCT-1 stimulates the IL-6/IL-6R/gp130/STAT3 axis, which promotes epithelial-to-mesenchymal transition and cancer stemness. Because cancer stemness largely contributes to the tumor metastasis and recurrence, we aimed to identify whether the blockade of MCT-1 and IL-6R can render these effects and to understand the underlying mechanisms that govern the process. Methods: We assessed primary tumor invasion, postsurgical local recurrence and distant metastasis in orthotopic syngeneic mice given the indicated immunotherapy and MCT-1 silencing (shMCT-1). Results: We found that shMCT-1 suppresses the transcriptomes of the inflammatory response and metastatic signaling in TNBC cells and inhibits tumor recurrence, metastasis and mortality in xenograft mice. IL-6R immunotherapy and shMCT-1 combined further decreased intratumoral M2 macrophages and T regulatory cells (Tregs) and avoided postsurgical TNBC expansion. shMCT-1 also enhances IL-6R-based immunotherapy effectively in preventing postsurgical TNBC metastasis, recurrence and mortality. Anti-IL-6R improved helper T, cytotoxic T and natural killer (NK) cells in the lymphatic system and decreased Tregs in the recurrent and metastatic tumors. Combined IL-6R and PD-L1 immunotherapies abridged TNBC cell stemness and M2 macrophage activity to a greater extent than monotherapy. Sequential immunotherapy of PD-L1 and IL-6R demonstrated the best survival outcome and lowest postoperative recurrence and metastasis compared with synchronized therapy, particularly in the shMCT-1 context. Multiple positive feedforward loops of the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 axis were identified in TNBC cells, which boosted metastatic niches and immunosuppressive microenvironments. Clinically, MCT-1high/PD-L1high/CXCL7high and CXCL7high/IL-6high/IL-6Rhigh expression patterns predict worse prognosis and poorer survival of breast cancer patients. Conclusion: Systemic targeting the MCT-1/IL-6/IL-6R/CXCL7/PD-L1 interconnections enhances immune surveillance that inhibits the aggressiveness of TNBC.

Intracellular biocompatible hexagonal boron nitride quantum emitters as single-photon sources and barcodes

Color centers in hexagonal boron nitride (hBN) have been emerging as a multifunctional platform for various optical applications including quantum information processing, quantum computing and imaging. Simultaneously, due to its biocompatibility and biodegradability hBN is a promising material for biomedical applications. In this work, we demonstrate single-photon emission from hBN color centers embedded inside live cells and their application to cellular barcoding. The generation and internalization of multiple color centers into cells was performed via simple and scalable procedure while keeping the cells unharmed. The emission from live cells was observed as multiple diffraction-limited spots, which exhibited excellent single-photon characteristics with high single-photon purity of 0.1 and superb emission stability without photobleaching or spectral shifts over several hours. Due to different emission wavelengths and peak widths of the color centers, they were employed as barcodes. We term them Quantum Photonic Barcodes (QPBs). Each QPB can exist in one out of 470 possible distinguishable states and a combination of a few QPBs per cell can be used to uniquely tag virtually an unlimited number of cells. The barcodes developed here offer some excellent properties, including ease of production by a single-step procedure, biocompatibility and biodegradability, emission stability, no photobleaching, small size and a huge number of unique barcodes. This work provides a basis for the use of hBN color centers for robust barcoding of cells and due to the single photon emission, presented concepts could in future be extended to quantum-limited sensing and super-resolution imaging.

Integrinβ-1 in disorders and cancers: molecular mechanisms and therapeutic targets

Integrinβ-1 (ITGB1) is a crucial member of the transmembrane glycoprotein signaling receptor family and is also central to the integrin family. It forms heterodimers with other ligands, participates in intracellular signaling and controls a variety of cellular processes, such as angiogenesis and the growth of neurons; because of its role in bidirectional signaling regulation both inside and outside the membrane, ITGB1 must interact with a multitude of substances, so a variety of interfering factors can affect ITGB1 and lead to changes in its function. Over the past 20 years, many studies have confirmed a clear causal relationship between ITGB1 dysregulation and cancer development and progression in a wide range of benign diseases and solid tumor types, which may imply that ITGB1 is a prognostic biomarker and a therapeutic target for cancer treatment that warrants further investigation. This review summarizes the biological roles of ITGB1 in benign diseases and cancers, and compiles the current status of ITGB1 function and therapy in various aspects of tumorigenesis and progression. Finally, future research directions and application prospects of ITGB1 are suggested. Video Abstract.

Mechanisms of Melanoma Progression and Treatment Resistance: Role of Cancer Stem-like Cells

Melanoma is the third most common type of skin cancer, characterized by its heterogeneity and propensity to metastasize to distant organs. Melanoma is a heterogeneous tumor, composed of genetically divergent subpopulations, including a small fraction of melanoma-initiating cancer stem-like cells (CSCs) and many non-cancer stem cells (non-CSCs). CSCs are characterized by their unique surface proteins associated with aberrant signaling pathways with a causal or consequential relationship with tumor progression, drug resistance, and recurrence. Melanomas also harbor significant alterations in functional genes (BRAF, CDKN2A, NRAS, TP53, and NF1). Of these, the most common are the BRAF and NRAS oncogenes, with 50% of melanomas demonstrating the BRAF mutation (BRAFV600E). While the successful targeting of BRAFV600E does improve overall survival, the long-term efficacy of available therapeutic options is limited due to adverse side effects and reduced clinical efficacy. Additionally, drug resistance develops rapidly via mechanisms involving fast feedback re-activation of MAPK signaling pathways. This article updates information relevant to the mechanisms of melanoma progression and resistance and particularly the mechanistic role of CSCs in melanoma progression, drug resistance, and recurrence.

Quantification of Nitric Oxide in Single Cells Using the Single-Probe Mass Spectrometry Technique

Nitric oxide (NO) is a small molecule that plays important roles in biological systems and human diseases. The abundance of intracellular NO is tightly related to numerous biological processes. Due to cell heterogeneity, the intracellular NO amounts significantly vary from cell to cell, and therefore, any meaningful studies need to be conducted at the single-cell level. However, measuring NO in single cells is very challenging, primarily due to the extremely small size of single cells and reactive nature of NO. In the current studies, the quantitative reaction between NO and amlodipine, a compound containing the Hantzsch ester group, was performed in live cells. The product dehydro amlodipine was then detected by the Single-probe single-cell mass spectrometry technique to quantify NO in single cells. The experimental results indicated heterogeneous distributions of intracellular NO amounts in single cells with the existence of subpopulations.

Notch receptor/ligand diversity: contribution to colorectal cancer stem cell heterogeneity

Cancer cell heterogeneity is a key contributor to therapeutic failure and post-treatment recurrence. Targeting cell subpopulations responsible for chemoresistance and recurrence seems to be an attractive approach to improve treatment outcome in cancer patients. However, this remains challenging due to the complexity and incomplete characterization of tumor cell subpopulations. The heterogeneity of cells exhibiting stemness-related features, such as self-renewal and chemoresistance, fuels this complexity. Notch signaling is a known regulator of cancer stem cell (CSC) features in colorectal cancer (CRC), though the effects of its heterogenous signaling on CRC cell stemness are only just emerging. In this review, we discuss how Notch ligand-receptor specificity contributes to regulating stemness, self-renewal, chemoresistance and cancer stem cells heterogeneity in CRC.

Exploring the dynamic interplay between cancer stem cells and the tumor microenvironment: implications for novel therapeutic strategies

Cancer stem cells (CSCs) have emerged as key contributors to tumor initiation, growth, and metastasis. In addition, CSCs play a significant role in inducing immune evasion, thereby compromising the effectiveness of cancer treatments. The reciprocal communication between CSCs and the tumor microenvironment (TME) is observed, with the TME providing a supportive niche for CSC survival and self-renewal, while CSCs, in turn, influence the polarization and persistence of the TME, promoting an immunosuppressive state. Consequently, these interactions hinder the efficacy of current cancer therapies, necessitating the exploration of novel therapeutic approaches to modulate the TME and target CSCs. In this review, we highlight the intricate strategies employed by CSCs to evade immune surveillance and develop resistance to therapies. Furthermore, we examine the dynamic interplay between CSCs and the TME, shedding light on how this interaction impacts cancer progression. Moreover, we provide an overview of advanced therapeutic strategies that specifically target CSCs and the TME, which hold promise for future clinical and translational studies in cancer treatment.

Editorial for "Impact of Regorafenib on Endothelial Transdifferentiation of Glioblastoma Stem-like Cells"

Glioblastoma multiforme (GBM) is the most frequently occurring form of malignant primary brain tumor in adults [...].

Deciphering Brain Metastasis Stem Cell Properties From Colorectal Cancer Highlights Specific Stemness Signature and Shared Molecular Features

BACKGROUND & AIMS

Brain metastases (BMs) from colorectal cancer (CRC) are associated with significant morbidity and mortality, with chemoresistance and short overall survival. Migrating cancer stem cells with the ability to initiate BM have been described in breast and lung cancers. In this study, we describe the identification and characterization of cancer stem cells in BM from CRC.

METHODS

Four brain metastasis stem cell lines from patients with colorectal cancer (BM-SC-CRC1 to BM-SC-CRC4) were obtained by mechanical dissociation of patient's tumors and selection of cancer stem cells by appropriate culture conditions. BM-SC-CRCs were characterized in vitro by clonogenic and limiting-dilution assays, as well as immunofluorescence and Western blot analyses. In ovo, a chicken chorioallantoic membrane (CAM) model and in vivo, xenograft experiments using BALB/c-nude mice were realized. Finally, a whole exome and RNA sequencing analyses were performed.

RESULTS

BM-SC-CRC formed metaspheres and contained tumor-initiating cells with self-renewal properties. They expressed stem cell surface markers (CD44v6, CD44, and EpCAM) in serum-free medium and CRC markers (CK19, CK20 and CDX-2) in fetal bovine serum-enriched medium. The CAM model demonstrated their invasive and migratory capabilities. Moreover, mice intracranial xenotransplantation of BM-SC-CRCs adequately recapitulated the original patient BM phenotype. Finally, transcriptomic and genomic approaches showed a significant enrichment of invasiveness and specific stemness signatures and highlighted KMT2C as a potential candidate gene to potentially identify high-risk CRC patients.

CONCLUSIONS

This original study represents the first step in CRC BM initiation and progression comprehension, and further investigation could open the way to new therapeutics avenues to improve patient prognosis.

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

Immuno-PET Imaging of CD69 Visualizes T-Cell Activation and Predicts Survival Following Immunotherapy in Murine Glioblastoma

Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults. Immunotherapy may be promising for the treatment of some patients with GBM; however, there is a need for noninvasive neuroimaging techniques to predict immunotherapeutic responses. The effectiveness of most immunotherapeutic strategies requires T-cell activation. Therefore, we aimed to evaluate an early marker of T-cell activation, CD69, for its use as an imaging biomarker of response to immunotherapy for GBM. Herein, we performed CD69 immunostaining on human and mouse T cells following in vitro activation and post immune checkpoint inhibitors (ICI) in an orthotopic syngeneic mouse glioma model. CD69 expression on tumor-infiltrating leukocytes was assessed using single-cell RNA sequencing (scRNA-seq) data from patients with recurrent GBM receiving ICI. Radiolabeled CD69 Ab PET/CT imaging (CD69 immuno-PET) was performed on GBM-bearing mice longitudinally to quantify CD69 and its association with survival following immunotherapy. We show CD69 expression is upregulated upon T-cell activation and on tumor-infiltrating lymphocytes (TIL) in response to immunotherapy. Similarly, scRNA-seq data demonstrated elevated CD69 on TILs from patients with ICI-treated recurrent GBM as compared with TILs from control cohorts. CD69 immuno-PET studies showed a significantly higher tracer uptake in the tumors of ICI-treated mice compared with controls. Importantly, we observed a positive correlation between survival and CD69 immuno-PET signals in immunotherapy-treated animals and established a trajectory of T-cell activation by virtue of CD69-immuno-PET measurements. Our study supports the potential use of CD69 immuno-PET as an immunotherapy response assessment imaging tool for patients with GBM.

Significance

Immunotherapy may hold promise for the treatment of some patients with GBM. There is a need to assess therapy responsiveness to allow the continuation of effective treatment in responders and to avoid ineffective treatment with potential adverse effects in the nonresponders. We demonstrate that noninvasive PET/CT imaging of CD69 may allow early detection of immunotherapy responsiveness in patients with GBM.

The role of tumor microenvironment on cancer stem cell fate in solid tumors

In the last few decades, the role of cancer stem cells in initiating tumors, metastasis, invasion, and resistance to therapies has been recognized as a potential target for tumor therapy. Understanding the mechanisms by which CSCs contribute to cancer progression can help to provide novel therapeutic approaches against solid tumors. In this line, the effects of mechanical forces on CSCs such as epithelial-mesenchymal transition, cellular plasticity, etc., the metabolism pathways of CSCs, players of the tumor microenvironment, and their influence on the regulating of CSCs can lead to cancer progression. This review focused on some of these mechanisms of CSCs, paving the way for a better understanding of their regulatory mechanisms and developing platforms for targeted therapies. While progress has been made in research, more studies will be required in the future to explore more aspects of how CSCs contribute to cancer progression. Video Abstract.

On the thermodynamics of DNA methylation process

DNA methylation is an epigenetic mechanism that plays important roles in various biological processes including transcriptional and post-transcriptional regulation, genomic imprinting, aging, and stress response to environmental changes and disease. Consistent with thermodynamic principles acting within living systems and the application of maximum entropy principle, we propose a theoretical framework to understand and decode the DNA methylation process. A central tenet of this argument is that the probability density function of DNA methylation information-divergence summarizes the statistical biophysics underlying spontaneous methylation background and implicitly bears on the channel capacity of molecular machines conforming to Shannon's capacity theorem. On this theoretical basis, contributions from the molecular machine (enzyme) logical operations to Gibb entropy (S) and Helmholtz free energy (F) are intrinsic. Application to the estimations of S on datasets from Arabidopsis thaliana suggests that, as a thermodynamic state variable, individual methylome entropy is completely determined by the current state of the system, which in biological terms translates to a correspondence between estimated entropy values and observable phenotypic state. In patients with different types of cancer, results suggest that a significant information loss occurs in the transition from differentiated (healthy) tissues to cancer cells. This type of analysis may have important implications for early-stage diagnostics. The analysis of entropy fluctuations on experimental datasets revealed existence of restrictions on the magnitude of genome-wide methylation changes originating by organismal response to environmental changes. Only dysfunctional stages observed in the Arabidopsis mutant met1 and in cancer cells do not conform to these rules.

Microcavity- and Microlaser-Based Optical Barcoding: A Review of Encoding Techniques and Applications

Optical microbarcodes have recently received a great deal of interest because of their suitability for a wide range of applications, such as multiplexed assays, cell tagging and tracking, anticounterfeiting, and product labeling. Spectral barcodes are especially promising because they are robust and have a simple readout. In addition, microcavity- and microlaser-based barcodes have very narrow spectra and therefore have the potential to generate millions of unique barcodes. This review begins with a discussion of the different types of barcodes and then focuses specifically on microcavity-based barcodes. While almost any kind of optical microcavity can be used for barcoding, currently whispering-gallery microcavities (in the form of spheres and disks), nanowire lasers, Fabry-Pérot lasers, random lasers, and distributed feedback lasers are the most frequently employed for this purpose. In microcavity-based barcodes, the information is encoded in various ways in the properties of the emitted light, most frequently in the spectrum. The barcode is dependent on the properties of the microcavity, such as the size, shape, and the gain materials. Various applications of these barcodes, including cell tracking, anticounterfeiting, and product labeling are described. Finally, the future prospects for microcavity- and microlaser-based barcodes are discussed.

TMT-based quantitative proteomic analysis of spheroid cells of endometrial cancer possessing cancer stem cell properties

BACKGROUND

Cancer stem cells (CSCs) play an important role in endometrial cancer progression and it is potential to isolate CSCs from spheroid cells. Further understanding of spheroid cells at protein level would help find novel CSC markers.

METHODS

Spheroid cells from endometrial cancer cell lines, Ishikawa and HEC1A, exhibited increased colony forming, subsphere forming, chemo-drug resistance, migration, invasion ability and tumorigenicity, verifying their cancer stem-like cell properties. The up-regulated CD90, CD117, CD133 and W5C5 expression also indicated stemness of spheroid cells. TMT-based quantitative proteomic analysis was performed to explore the potential alterations between parent cells and cancer stem-like spheroid cells. HK2-siRNA was transfected to Ishikawa and HEC1A cells to explore the roles and molecular mechanism of HK2 in endometrial cancer.

RESULTS

We identified and quantified a total of 5735 proteins and 167 overlapped differentially expressed proteins of two cell types, 43 proteins were up-regulated and 124 were down-regulated in spheroid cells comparing with parent cells. KEGG pathway revealed a significant role of HIF-1 pathway in spheroid cells. qRT-PCR and western blot results of GPRC5A, PFKFB3 and HK2 of HIF-1 pathway confirmed their elevated expressions in spheroid cells which were consistent with proteomic results. HK2 promoted cancer stemness in endometrial cancer.

CONCLUSION

These findings indicate that spheroid cells from endometrial cancer cell lines possess cancer stem-like cell properties and enrich CSCs. HIF-1 pathway is activated in endometrial cancer stem-like spheroid cells.

Identification of Prominent Genes between 3D Glioblastoma Models and Clinical Samples via GEO/TCGA/CGGA Data Analysis

A paradigm shift in preclinical evaluations of new anticancer GBM drugs should occur in favour of 3D cultures. This study leveraged the vast genomic data banks to investigate the suitability of 3D cultures as cell-based models for GBM. We hypothesised that correlating genes that are highly upregulated in 3D GBM models will have an impact in GBM patients, which will support 3D cultures as more reliable preclinical models for GBM. Using clinical samples of brain tissue from healthy individuals and GBM patients from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Chinese Glioma Genome Atlas (CGGA), and Genotype-Tissue Expression (GTEx) databases, several genes related to pathways such as epithelial-to-mesenchymal transition (EMT)-related genes (CD44, TWIST1, SNAI1, CDH2, FN1, VIM), angiogenesis/migration-related genes (MMP1, MMP2, MMP9, VEGFA), hypoxia-related genes (HIF1A, PLAT), stemness-related genes (SOX2, PROM1, NES, FOS), and genes involved in the Wnt signalling pathway (DKK1, FZD7) were found to be upregulated in brain samples from GBM patients, and the expression of these genes were also enhanced in 3D GBM cells. Additionally, EMT-related genes were upregulated in GBM archetypes (wild-type IDH1^R132 ) that historically have poorer treatment responses, with said genes being significant predictors of poorer survival in the TCGA cohort. These findings reinforced the hypothesis that 3D GBM cultures can be used as reliable models to study increased epithelial-to-mesenchymal transitions in clinical GBM samples.

Targeting CDK12 obviates the malignant phenotypes of colorectal cancer through the Wnt/β-catenin signaling pathway

Colorectal cancer (CRC) is the second most common cause of cancer-related mortality and lies third in terms of morbidity due to the limited number of effective druggable targets. Since cancer stem cells (CSCs) are considered to be one of the roots of tumorigenesis, outgrowth and metastasis, targeting CSCs may be a promising strategy to reverse the malignant phenotypes of CRC. Cyclin-dependent kinase 12 (CDK12) has been reported to be involved in the self-renewal of CSCs in various cancers, rendering it an attractive potential target against CSCs to consequently limit the malignant phenotypes in CRC. In the present study, we aimed to investigate whether CDK12 can be a potential therapeutic target for patients with CRC and clarify its underlying mechanism. We found that CDK12, but not CDK13 is required for CRC survival. CDK12 was found to drive tumor initiation according to the colitis-associated colorectal cancer mouse model. In addition, CDK12 promoted CRC outgrowth and hepatic metastasis in the subcutaneous allograft and liver metastasis mouse models, respectively. In particular, CDK12 was able to induce the self-renewal of CRC CSCs. Mechanistically, the activation of Wnt/β-catenin signaling mediated by CDK12 was implicated in stemness regulation and malignant phenotype maintenance. These findings indicate that CDK12 is a candidate druggable target in CRC. Therefore, the CDK12 inhibitor SR-4835 warrants clinical trial testing in patients with CRC.

Proteomic profiling and ROC analysis identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug in resistant TNBC

Triple-negative breast cancer is high heterogeneous, aggressive, and metastatic with poor prognosis. Despite of advances in targeted therapies, TNBC has been reported to cause high morbidity and mortality. A rare subpopulation within the tumor microenvironment organized into a hierarchy of cancer stem cells is responsible for therapy resistance and tumor recurrence. Repurposing of antiviral drugs for cancer treatment is gaining momentum due to reduced cost, labour, and research time, but limited due to lack of prognostic, and predictive markers. The present study investigates proteomic profiling and ROC analysis to identify CD151 and ELAVL1 as potential therapy response markers for the antiviral drug 2-thio-6-azauridine (TAU) in resistant TNBC. The stemness of MDA-MB 231 and MDA-MD 468 adherent cells was enriched by culturing them under non-adherent and non-differentiation conditions. Then, CD151⁺ subpopulation was isolated and characterized for the enrichment of stemness. This study found that CD151 has overexpressed in stemness enriched subpopulations, and also showed CD44 high and CD24 low expression along with stem cell-related transcription factors octamer-binding transcription factor 4 (OCT4) and Sex determining Y-box 2 (SOX2). This study also found that TAU induced significant cytotoxicity and genotoxicity in the CD151⁺TNBC subpopulation and inhibited their proliferation by inducing DNA damage, cell cycle arrest at the G₂M phase, and apoptosis. Further, a proteomic profiling study showed that the expression of CD151 along with ELAVL1, an RNA-binding protein, was significantly reduced with TAU treatment. KM plotter showed correlation of CD151 and ELAVL1 gene expression with a poor prognosis of TNBC. ROC analysis predicted and validated CD151 and ELAVL1 as best therapy response marker for TAU in TNBC. These findings provide new insight into repurposing antiviral drug TAU for treatment of metastatic and drug resistant TNBC.

KISS1 metastasis suppressor in tumor dormancy: a potential therapeutic target for metastatic cancers?

Present therapeutic approaches do not effectively target metastatic cancers, often limited by their inability to eliminate already-seeded non-proliferative, growth-arrested, or therapy-resistant tumor cells. Devising effective approaches targeting dormant tumor cells has been a focus of cancer clinicians for decades. However, progress has been limited due to limited understanding of the tumor dormancy process. Studies on tumor dormancy have picked up pace and have resulted in the identification of several regulators. This review focuses on KISS1, a metastasis suppressor gene that suppresses metastasis by keeping tumor cells in a state of dormancy at ectopic sites. The review explores mechanistic insights of KISS1 and discusses its potential application as a therapeutic against metastatic cancers by eliminating quiescent cells or inducing long-term dormancy in tumor cells.

PARP-1 Expression Influences Cancer Stem Cell Phenotype in Colorectal Cancer Depending on p53

Poly(ADP-ribose) polymerase-1 (PARP-1) is a protein involved in multiple physiological processes. Elevated PARP-1 expression has been found in several tumours, being associated with stemness and tumorigenesis. In colorectal cancer (CRC), some controversy among studies has been described. In this study, we analysed the expression of PARP-1 and cancer stem cell (CSC) markers in CRC patients with different p53 status. In addition, we used an in vitro model to evaluate the influence of PARP-1 in CSC phenotype regarding p53. In CRC patients, PARP-1 expression correlated with the differentiation grade, but this association was only maintained for tumours harbouring wild-type p53. Additionally, in those tumours, PARP-1 and CSC markers were positively correlated. In mutated p53 tumours, no associations were found, but PARP-1 was an independent factor for survival. According to our in vitro model, PARP-1 regulates CSC phenotype depending on p53 status. PARP-1 overexpression in a wild type p53 context increases CSC markers and sphere forming ability. By contrast, those features were reduced in mutated p53 cells. These results could implicate that patients with elevated PARP-1 expression and wild type p53 could benefit from PARP-1 inhibition therapies, meanwhile it could have adverse effects for those carrying mutated p53 tumours.

AT7867 Inhibits the Growth of Colorectal Cancer Stem-Like Cells and Stemness by Regulating the Stem Cell Maintenance Factor Ascl2 and Akt Signaling

Cancer stem cells (CSCs) are the core factors leading to recurrence, insensitivity to radiotherapy and chemotherapy, and immunotherapy resistance in patients with colorectal cancer. AT7867, a potent oral AKT inhibitor, was found to have antitumor activity in colorectal cancer; however, the effect on colorectal cancer stem cells is still unclear. This study was conducted to clarify the molecular mechanism underlying the CSC growth inhibitory effects of AT7867. We cultured colorectal cancer cells (CRCs) in a serum-free medium and enriched colorectal cancer stem cells. Subsequently, the effects of AT7867 on CSCs were analyzed by CCK-8, colony formation, flow cytometry, and immunofluorescence assays. The results indicated that AT7867 induces G2/M phase arrest and cell apoptosis in cancer stem cells. Subsequently, we identified Ascl2 as the main gene affecting the stemness of colorectal cancer in AT7867 by RNA sequencing. The current study showed that Ascl2 is involved in the metastasis, invasion, and proliferation of CRCs. The next experiments demonstrated that overexpression of Ascl2 did affect the therapeutic effect of AT7867 on CRC stemness. Furthermore, compared with other Akt inhibitors, AT7867 could promote the differentiation of colorectal cancer stem cells. Thus, AT7867 might be a potential antitumor drug candidate to treat CRC by targeting CSCs.