Inhibition Of Cancer Stem Cells Research Articles

SiRNA treatment targeting integrin α11 overexpressed via EZH2-driven axis inhibits drug-resistant breast cancer progression

BackgroundBreast cancer, the most prevalent cancer in women worldwide, faces treatment challenges due to drug resistance, posing a serious threat to patient survival. The present study aimed to identify the key molecules that drive drug resistance and aggressiveness in breast cancer cells and validate them as therapeutic targets.MethodsTranscriptome microarray and analysis using PANTHER pathway and StemChecker were performed to identify the most significantly expressed genes in tamoxifen-resistant and adriamycin-resistant MCF-7 breast cancer cells. Clinical relevance of the key genes was determined using Kaplan-Meier survival analyses on The Cancer Genome Atlas dataset of breast cancer patients. Gene overexpression/knockdown, spheroid formation, flow cytometric analysis, chromatin immunoprecipitation, immunocytochemistry, wound healing/transwell migration assays, and cancer stem cell transcription factor activation profiling array were used to elucidate the regulatory mechanism of integrin α11 expression. Tumour-bearing xenograft models were used to demonstrate integrin α11 is a potential therapeutic target.ResultsIntegrin α11 was consistently upregulated in drug-resistant breast cancer cells, and its silencing inhibited cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) while restoring sensitivity to anticancer drugs. HIF1α, GLI-1, and EZH2 contributed the most to the regulation of integrin α11 and EZH2 expression, with EZH2 being more necessary for EZH2 autoinduction than HIF1α and GLI-1. Additionally, unlike HIF1α or EZH2, GLI-1 was the sole transcription factor activated by integrin-linked focal adhesion kinase, indicating GLI-1 as a key driver of the EZH2-integrin α11 axis operating for cancer stem cell survival and EMT. Kaplan-Meier survival analysis using The Cancer Genome Atlas (TCGA) dataset also revealed both EZH2 and integrin α11 could be strong prognostic factors of relapse-free and overall survival in breast cancer patients. However, the superior efficacy of integrin α11 siRNA therapy over EZH2 siRNA treatment was demonstrated by enhanced inhibition of tumour growth and prolonged survival in murine models bearing tumours.ConclusionOur findings elucidate that integrin α11 is upregulated by EZH2, forming a positive feedback circuit involving FAK-GLI-1 and contributing to drug resistance, cancer stem cell survival and EMT. Taken together, the results suggest integrin α11 as a promising prognostic marker and a powerful therapeutic target for drug-resistant breast cancer.

Targeting CD73 with flavonoids inhibits cancer stem cells and increases lymphocyte infiltration in a triple-negative breast cancer mouse model.

Chemotherapy remains the mainstay treatment for triple-negative breast cancer (TNBC) due to the lack of specific targets. Given a modest response of immune checkpoint inhibitors in TNBC patients, improving immunotherapy is an urgent and crucial task in this field. CD73 has emerged as a novel immunotherapeutic target, given its elevated expression on tumor, stromal, and specific immune cells, and its established role in inhibiting anti-cancer immunity. CD73-generated adenosine suppresses immunity by attenuating tumor-infiltrating T- and NK-cell activation, while amplifying regulatory T cell activation. Chemotherapy often leads to increased CD73 expression and activity, further suppressing anti-tumor immunity. While debulking the tumor mass, chemotherapy also enriches heterogenous cancer stem cells (CSC), potentially leading to tumor relapse. Therefore, drugs targeting both CD73, and CSCs hold promise for enhancing chemotherapy efficacy, overcoming treatment resistance, and improving clinical outcomes. However, safe and effective inhibitors of CD73 have not been developed as of now. We used in silico docking to screen compounds that may be repurposed for inhibiting CD73. The efficacy of these compounds was investigated through flow cytometry, RT-qPCR, CD73 activity, cell viability, tumorsphere formation, and other in vitro functional assays. For assessment of clinical translatability, TNBC patient-derived xenograft organotypic cultures were utilized. We also employed the ovalbumin-expressing AT3 TNBC mouse model to evaluate tumor-specific lymphocyte responses. We identified quercetin and luteolin, currently used as over-the-counter supplements, to have high in silico complementarity with CD73. When quercetin and luteolin were combined with the chemotherapeutic paclitaxel in a triple-drug regimen, we found an effective downregulation in paclitaxel-enhanced CD73 and CSC-promoting pathways YAP and Wnt. We found that CD73 expression was required for the maintenance of CD44highCD24low CSCs, and co-targeting CD73, YAP, and Wnt effectively suppressed the growth of human TNBC cell lines and patient-derived xenograft organotypic cultures. Furthermore, triple-drug combination inhibited paclitaxel-enriched CSCs and simultaneously improved lymphocyte infiltration in syngeneic TNBC mouse tumors. Conclusively, our findings elucidate the significance of CSCs in impairing anti-tumor immunity. The high efficacy of our triple-drug regimen in clinically relevant platforms not only underscores the importance for further mechanistic investigations but also paves the way for potential development of new, safe, and cost-effective therapeutic strategies for TNBC.

Abstract 5120: Direct targeting of the COMPASS complex inhibits neuroblastoma growth by inhibiting cancer stem cells

Abstract Epigenetic regulator COMPASS Complex, a histone H3K4 methyltransferase has recently been shown to be involved in multiple cancers and attaining focus as a novel therapeutic target. High-risk neuroblastoma (NB) is a heterogeneous pediatric cancer with high mortality and relapse rates. The relapse of refractory cancer is shown to be driven by cancer stem cells (CSCs), which are maintained by epigenetic malfunctions. In the present study, we determined the effects of inhibiting the COMPASS complex on NB CSCs and overall NB growth. A high-throughput shRNA screening of methyltransferases and demethylases reveals the role of COMPASS complex partners MLL1 and Menin in NB proliferation. We found that both MLL1 and Menin are overexpressed in our previously identified CD114+ NB CSCs. Further, MEN1 (gene coding Menin) expression showed an inverse correlation with overall NB patient survival and cancer progression in a comprehensive analysis of 1235 primary NB patient data. Our ChIP results show that the CSF3R gene which codes for CD114 and maintains CD114+ NB CSCs, is regulated by the presence of high H3K4me3 activating marks. Further, we used MI-503 to inhibit MLL1-Menin interaction and also developed MEN1 stable knockdown and found that both strategies significantly inhibit H3K4me3 activity in NB, particularly at the CSF3R gene promoter. This led to decreased CSF3R expression and NB CSC levels. MI-503 significantly inhibits proliferation in different NB cell lines and primary patient-derived xenograft (PDX) lines, with minimal effect on non-cancerous fibroblasts. MI-503 significantly inhibits NB cell cycle progression at the S phase, induces apoptosis, and inhibits NB 3D spheroid growth and development. Interestingly, we overserved differential selectivity of MI-503 in inducing apoptosis and in blocking the cell cycle in NB CSCs in contrast to non-CSCs. MEN1 knockdown also inhibits NB proliferation and 3D spheroid growth. Furthermore, MI-503 in a dose-dependent manner synergistically sensitizes NB to chemotherapy doxorubicin and significantly inhibits NB proliferation and spheroid growth compared to either agent alone. Further, by using the NB xenograft in vivo tumor model, we established that MI-503 significantly inhibits NB tumor growth and tumor metastasis by directly inhibiting tumor NB CSCs, without any observed toxicities. Similar results of significantly reduced tumor growth, metastasis, and NB CSCs were shown by the MEN1 knockdown in vivo. Overall, our data show that the MLL1-Menin of the COMPASS complex directly activates the CSF3R gene to maintain NB CSCs and drive NB pathogenesis. Our data show that MI-503 or MEN1 knockdown leads to significant inhibition of NB growth by directly inhibiting NB CSCs in both in vitro and in vivo tumor models. Further developing these epigenetic-based therapeutic strategies and combining them with current therapies will pave the way for effectively managing NB. Citation Format: Rameswari Chilamakuri, Saurabh Agarwal. Direct targeting of the COMPASS complex inhibits neuroblastoma growth by inhibiting cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5120.

Unlocking the effective alliance of β-lapachone and hydroxytyrosol against triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is characterised by its aggressiveness and resistance to chemotherapy, demanding the development of effective strategies against its unique characteristics. Derived from lapacho tree bark, β-lapachone (β-LP) selectively targets cancer cells with elevated levels of the detoxifying enzyme NQO1. Hydroxytyrosol (HT) is a phenolic compound derived from olive trees with important anticancer properties that include the inhibition of cancer stem cells (CSCs) and metastatic features in TNBC, as well as relevant antioxidant activities by mechanisms such as the induction of NQO1. We aimed to study whether these compounds could have synergistic anticancer activity in TNBC cells and the possible role of NQO1. For this pourpose, we assessed the impact of β-LP (0.5 or 1.5 μM) and HT (50 and 100 μM) on five TNBC cell lines. We demonstrated that the combination of β-LP and HT exhibits anti-proliferative, pro-apoptotic, and cell cycle arrest effects in several TNBC cells, including docetaxel-resistant TNBC cells. Additionally, it effectively inhibits the self-renewal and clonogenicity of CSCs, modifying their aggressive phenotype. However, the notable impact of the β-LP-HT combination does not appear to be solely associated with the levels of the NQO1 protein and ROS. RNA-Seq analysis revealed that the combination's anticancer activity is linked to a strong induction of endoplasmic reticulum stress and apoptosis through the unfolded protein response. In conclusion, in this study, we demonstrated how the combination of β-LP and HT could offer an affordable, safe, and effective approach against TNBC.

Organosulfur Compounds in Colorectal Cancer Prevention and Progression.

This work represents an overview of the current investigations involving organosulfur compounds and colorectal cancer. The molecules discussed in this review have been investigated regarding their impact on colorectal cancer directly, at the in vitro, in vivo, and clinical stages. Organosulfur compounds may have indirect effects on colorectal cancer, such as due to their modulating effects on the intestinal microbiota or their positive effects on intestinal mucosal health. Here, we focus on their direct effects via the repression of multidrug resistance proteins, triggering of apoptosis (via the inhibition of histone deacetylases, increases in reactive oxygen species, p53 activation, β-catenin inhibition, damage in the mitochondrial membrane, etc.), activation of TGF-β, binding to tubulin, inhibition of angiogenesis and metastasis mechanisms, and inhibition of cancer stem cells, among others. In general, the interesting positive effects of these nutraceuticals in in vitro tests must be further analyzed with more in vivo models before conducting clinical trials.

CTNI-21. PHASE I STUDY OF BTK INHIBITOR IBRUTINIB WITH TEMOZOLOMIDE AND RADIATION IN NEWLY-DIAGNOSED GLIOBLASTOMA (EQUILIBRIUM): FINAL TRIAL REPORT

Abstract BACKGROUND Glioblastoma carries dismal prognosis for which novel therapeutics are urgently needed. Ibrutinib, an oral small molecule inhibitor of BTK, has been shown in preclinical models to inhibit cancer stem cells in glioblastoma. We sought to investigate safety and tolerability of ibrutinib for newly-diagnosed glioblastoma (nGBM). METHODS EQUILIBRIUM was a prospective, phase I trial conducted in nGBM patients with KPS ≥ 70% and normal organ function. Patients received standard of care chemoradiation plus ibrutinib in a 3 + 3 dose-escalation design (level 1: 420 mg daily, level 2: 560 mg daily, level -1: 280 mg daily). Primary study objective was to determine maximum tolerated dose (MTD) of ibrutinib in combination with radiotherapy (RT) of 60Gy over 6 weeks with/without 75 mg/m2 of temozolomide (TMZ) in MGMT methylated and unmethylated cohorts respectively. Secondary objective was to determine safety, overall survival (OS), and progression-free survival. RESULTS 26 patients were enrolled, with 12 (46%) females. Median age was 61.5 years (range 76-22). 15 (58%) patients were MGMT methylated and 11 (42%) were unmethylated. Dose-limiting toxicities (DLTs) were observed at all dose levels of ibrutinib+RT arm. MTD of ibrutinib was noted to be 420 mg daily with RT+TMZ in methylated arm. In Ibrutinib+RT+TMZ arm, median cycles of TMZ were 4 (range 0-6) and of ibrutinib were 3 (range 0-26). Median OS for MGMT methylated arm was 26.0 (22.0-NA) months and for MGMT unmethylated cohort was 14.0 (8.54-NA) months. Median OS for EGFR-amplified was 29.5 (21.9-NA) months and for EGFR-non-amplified was 21.8 (16.6-NA) months. 2-year OS for MGMT methylated arm was 56% (34-95%) and for MGMT unmethylated arm was 2% (6-70%). CONCLUSIONS 420 mg of Ibrutinib daily is safe and feasible with TMZ and RT for nGBM. Ibrutinib appears promising compared to historical outcomes in MGMT methylated patients. EGFR-amplified patients potentially derive significant benefit. Trial information: NCT03535350.

Cancer Stem Cells and Treatment of Cancer: An Update and Future Perspectives.

Cancer stem cells (CSCs) play an essential role in tumour progression and metastasis. These cells have the unique ability to self-renew and differentiate into specific tissue cell types. Their capacity for self-renewal enables CSCs to persist over time, thereby contributing to cancer relapse and therapy resistance. Therefore, targeting CSCs has emerged as a promising cancer treatment strategy. CSCs exhibit differentiation, self-renewal, and plasticity, and they contribute to multiple aspects of malignant tumours, such as recurrence, metastasis, heterogeneity, multidrug resistance, and radiation resistance. While conventional treatments predominantly target cancer cells that are not CSCs, CSCs frequently survive, resulting in tumour recurrence and relapse. This article concentrates on the development of novel therapeutic strategies that combine conventional treatments with CSC inhibitors to eradicate cancer cells and CSCs, thereby treating cancer and preventing its recurrence. However, the diversity of CSCs poses a significant obstacle to the development of CSC-targeted therapies, necessitating extensive research for a better understanding and exploration of therapeutic approaches. Future development of CSC-targeted therapies will rely heavily on overcoming this obstacle.

Biomimetic biomineralization nanoplatform-mediated differentiation therapy and phototherapy for cancer stem cell inhibition and antitumor immunity activation

Growing evidence suggests that the presence of cancer stem cells (CSCs) is a major challenge in current tumor treatments, especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis. Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy. In this work, we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid (ATRA) via biomineralization. This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters, which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration. With the help of CSC differentiation induced by ATRA, IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner. Furthermore, ATRA can boost immunogenic cell death induced by phototherapy, thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells. Taken together, this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation, improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.

Identification of a novel combination treatment strategy in clear cell renal cell carcinoma stem cells with shikonin and ipilimumab.

Management of clear cell renal cell carcinoma (ccRCC) has changed rapidly in recent years with the advent of immune checkpoint inhibitors (ICIs). However, only a limited number of patients can sustainably respond to immune checkpoint inhibitors and many patients develop resistance to therapy, creating an additional need for therapeutic strategies to improve the efficacy of systemic therapies. Binding probability and target genes prediction using online databases, invasion, migration, and apoptosis assays as well as the inhibition of cancer stem cells (CSCs) markers in ccRCC cell lines were used to select the most promising phytochemicals (PTCs). Mixed lymphocyte tumor cell culture (MLTC) system and flow cytometry were performed to confirm the potential combination strategy. The potential immunotherapeutic targets and novel CSC markers were identified via the NanoString analysis. The mRNA and protein expression, immune signatures as well as survival characteristics of the marker in ccRCC were analyzed via bioinformation analysis. Shikonin was selected as the most promising beneficial combination partner among 11 PTCs for ipilimumab for the treatment of ccRCC patients due to its strong inhibitory effect on CSCs, the significant reduction of FoxP3+ Treg cells in peripheral blood mononuclear cells (PBMCs) of patients and activation of the endogenous effector CD3+CD8+ and CD3+CD4+ T cells in response to the recognition of tumor specific antigens. Based on NanoString analysis VCAM1, CXCL1 and IL8 were explored as potential immunotherapeutic targets and novel CSC markers in ccRCC. The expression of VCAM1 was higher in the tumor tissue both at mRNA and protein levels in ccRCC compared with normal tissue, and was significantly positively correlated with immune signatures and survival characteristics in ccRCC patients. We propose that a combination of shikonin and ipilimumab could be a promising treatment strategy and VCAM1 a novel immunotherapeutic target for the treatment of ccRCC.

A phenol amine molecule from Salinivenus iranica acts as the inhibitor of cancer stem cells in breast cancer cell lines

In recent years, the anticancer properties of metabolites from halophilic microorganisms have received a lot of attention. Twenty-nine halophilic bacterial strains were selected from a culture collection to test the effects of their supernatant metabolites on stem cell-like properties of six human cancer cell lines. Human fibroblasts were used as normal control. Sphere and colony formation assay were done to assess the stem cell-like properties. invasion and migration assay, and tumor development in mice model were done to assess the anti-tumorigenesis effect in vitro and in vivo. The metabolites from Salinivenus iranica demonstrated the most potent cytotoxic effect on breast cancer cell lines (IC50 = 100 µg/mL) among all strains, with no effect on normal cells. In MDA-MB-231 cells, the supernatant metabolites enhanced both early and late apoptosis (approximately 9.5% and 48.8%, respectively) and decreased the sphere and colony formation ability of breast cancer cells. Furthermore, after intratumor injection of metabolites, tumors developed in the mice models reduced dramatically, associated with increased pro-apoptotic caspase-3 expression. The purified cytotoxic molecule, a phenol amine with a molecular weight of 1961.73 Dalton (IC50 = 1 µg/mL), downregulated pluripotency gene SRY-Box Transcription Factor 2 (SOX-2) expression in breast cancer cells which is associated with resistance to conventional anticancer treatment. In conclusion, we suggested that the phenol amine molecule from Salinivenus iranica could be a potential anti-breast cancer component.

Black Phosphorus as a Targeting PPAR-γ Agonist to Reverse Chemoresistance in Patient-derived Organoids, Mice, and Pancreatic Tumor Cells.

Black phosphorus (BP) exhibits significant potential for clinical applications. However, further research is necessary to uncover the unknown biological functions of BP and broaden its applications across various fields. This study investigates the potential of BP as a targeting PPAR-γ agonist to overcome chemoresistance in the treatment of pancreatic adenocarcinoma (PAAD) using 2D and 3D cell lines, patient-derived organoids (PDOs), and mouse models. RNA-sequencing analysis shows that BP treatment enriches differentially expressed genes in the PPAR pathway, and molecular modeling predicts the potential docking site between BP and PPAR-γ. Transcriptional activity assays are further to verify the activation of PPAR-γ. BP-activated PPAR-γ inhibits cancer stem cell (CSC) properties and expression of biomarkers such as CD44 and c-Myc, which are involved in chemoresistance. Notably, CD44 overexpression in tumor cells renders them susceptible to BP while insensitive to gemcitabine. This indicates that BP preferentially targets stem-like cells, which exhibit heightened resistance to chemotherapeutic drugs. A combination treatment strategy involving BP and gemcitabine is developed, demonstrating enhanced treatment efficacy of PAAD in both in vitro and in vivo models. Thus, BP serves as a PPAR-γ agonist capable of reversing chemoresistance, establishing it as a potent anti-tumor approach for the treatment of PAAD.

Unravelling the Therapeutic Potential of Antibiotics in Hypoxia in a Breast Cancer MCF-7 Cell Line Model.

Antibiotics inhibit breast cancer stem cells (CSCs) by suppressing mitochondrial biogenesis. However, the effectiveness of antibiotics in clinical settings is inconsistent. This inconsistency raises the question of whether the tumor microenvironment, particularly hypoxia, plays a role in the response to antibiotics. Therefore, the goal of this study was to evaluate the effectiveness of five commonly used antibiotics for inhibiting CSCs under hypoxia using an MCF-7 cell line model. We assessed the number of CSCs through the mammosphere formation assay and aldehyde dehydrogenase (ALDH)-bright cell count. Additionally, we examined the impact of antibiotics on the mitochondrial stress response and membrane potential. Furthermore, we analyzed the levels of proteins associated with therapeutic resistance. There was no significant difference in the number of CSCs between cells cultured under normoxic and hypoxic conditions. However, hypoxia did affect the rate of CSC inhibition by antibiotics. Specifically, azithromycin was unable to inhibit sphere formation in hypoxia. Erythromycin and doxycycline did not reduce the ratio of ALDH-bright cells, despite decreasing the number of mammospheres. Furthermore, treatment with chloramphenicol, doxycycline, and tetracycline led to the overexpression of the breast cancer resistance protein. Our findings suggest that hypoxia may weaken the inhibitory effects of antibiotics on the breast cancer model.

A FOXC2 inhibitor, MC-1-F2, as a therapeutic candidate for targeting EMT in castration-resistant prostate cancer

Androgen deprivation therapy (ADT) is the major treatment option for advanced prostate cancer. However, prostate cancer can develop into androgen-independent castration-resistant prostate cancer (CRPC) which is resistant to ADT. An alternative treatment strategy for CRPC can be targeting the epithelial-mesenchymal transition (EMT). EMT is governed by a series of transcription factors of which forkhead box protein C2 (FOXC2) is a central mediator. Our previous research into the inhibition of FOXC2 in breast cancer cells lead to the discovery of MC-1-F2, the first direct inhibitor of FOXC2. In current study on CRPC, MC-1-F2 has shown a decrease in mesenchymal markers, inhibition of cancer stem cell (CSC) properties and decrease in invasive capabilities of CRPC cell lines. We have also demonstrated a synergistic effect between MC-1-F2 and docetaxel treatments, leading to a decrease in docetaxel dosage, suggesting the possible combination therapy of MC-1-F2 and docetaxel for the effective treatment of CRPC.

The Role of Cancer and Somatic Stem Cells in the Anti-Inflammatory and Antitumor Effects of Aconitum baicalense Extract on Experimental Breast Cancer.

We studied the effects of the extract of the terrestrial part of Aconitum baicalense in BALB/c female mice at the early stages after the injection of N-methyl-N-nitrosourea (MNU). The extract reduced inflammatory activity and tumor growth in the mammary gland. The antitumor and anti-inflammatory effects of the extract are based on the inhibition of cancer stem cells, hematopoietic stem cells, and hematopoietic progenitor cells that promote inflammation. The extract of A. baicalense disrupted the recruitment of epithelial progenitor cells and angiogenesis precursors to the mammary gland preventing neovascularization and transformation of epithelial cells into tumor cells.

Phase I study of BTK inhibitor ibrutinib with temozolomide and radiation in newly-diagnosed glioblastoma (EQUILIBRIUM): Final trial report.

2067 Background: Novel therapeutic strategies are urgently needed in newly-diagnosed glioblastoma (GBM). Ibrutinib, an oral small molecule inhibitor of BTK, is currently being investigated for several B-cell malignancies and solid tumors. Preclinical evidence suggests ibrutinib in inhibiting cancer stem cell in glioblastoma. We sought to investigate the safety and tolerability of ibrutinib in nGBM. Methods: A non-randomized, prospective phase I trial was conducted in nGBM patients with Karnofsky performance status ≥70% and normal organ function, who received standard of care chemoradiation plus ibrutinib in a 3+3 dose-escalation design (level 1: 420 mg daily, level 2: 560 mg daily, level -1: 280 mg daily). Primary study objective was to determine maximum tolerated dose (MTD) of ibrutinib in combination with radiotherapy (RT) of 60 Gy over 6 weeks with/without 75 mg/m2 of temozolomide (TMZ). Secondary objective was to determine safety, overall survival (OS), and progression-free survival. Results: 26 patients were enrolled, with 12 (46%) females. Median age was 61.5 years (range 76-22). 15 (58%) patients were MGMT methylated and 11 (42%) were unmethylated. Dose-limiting toxicities (DLTs) were observed at all dose levels of ibrutinib plus RT (ibru+RT) cohort. MTD of ibrutinib was noted to be 420 mg daily with RT+TMZ. All MGMT methylated and 2 unmethylated patients received ibrutinib+RT+TMZ. Remaining 9 unmethylated received ibru+RT. In ibru+RT+TMZ, median cycles of TMZ were 4 (range 0-6) and of ibrutinib were 3 (range 0-26). EGFR amplification status was available for 22 patients, of which 8 (36%) were amplified. Survival outcomes are described, stratified using log-rank test. Conclusions: 420 mg of Ibrutinib daily is safe and feasible in combination with TMZ and radiation in nGBM. Outcomes of ibrutinib appears promising compared to historical survival data in the MGMT methylated cohorts. Further trials are planned. Clinical trial information: NCT03535350 . [Table: see text]

Dual targeting salinomycin-loaded smart nanomicelles for enhanced accumulation and therapeutic outcome in breast cancer

Salinomycin is a polyether compound that exhibits strong anticancer activity and is known as the cancer stem cell inhibitor that reached clinical testing. The rapid elimination of nanoparticles from the bloodstream by the mononuclear phagocyte system (MPS), the liver, and the spleen, accompanied by protein corona (PC) formation, restricts in vivo delivery of nanoparticles in the tumor microenvironment (TME). The DNA aptamer (TA1) that successfully targets the overexpressed CD44 antigen on the surface of breast cancer cells suffers strongly from PC formation in vivo. Thus, cleverly designed targeted strategies that lead to the accumulation of nanoparticles in the tumor become a top priority in the drug delivery field. In this work, dual redox/pH-sensitive poly (β-amino ester) copolymeric micelles modified with CSRLSLPGSSSKpalmSSS peptide and TA1 aptamer, as dual targeting ligands, were synthesized and fully characterized by physico-chemical methods. These biologically transformable stealth NPs were altered into the two ligand-capped (SRL-2 and TA1) NPs for synergistic targeting of the 4T1 breast cancer model after exposure to the TME. The PC formation was reduced sharply in Raw 264.7 cells by increasing the CSRLSLPGSSSKpalmSSS peptide concentration in modified micelles. Surprisingly, in vitro and in vivo biodistribution findings showed that dual targeted micelle accumulation in the TME of 4T1 breast cancer model was significantly higher than that of single modified formulation, along with deep penetration 24 h after intraperitoneal injection. Also, an in vivo treatment study showed remarkable tumor growth inhibition in 4T1 tumor-bearing Balb/c mice, compared to different formulations, with a 10% lower therapeutic dose (TD) of SAL that was confirmed by hematoxylin and eosin staining (H&E) and the TUNEL assay. Overall, in this study, we developed smart transformable NPs in which the body's own engineering systems alter their biological identity, which resulted in a reduction in therapeutic dosage along with a lowered off-target effect.

Hyperbaric Oxygen Activates Enzyme-Driven Cascade Reactions for Cooperative Cancer Therapy and Cancer Stem Cells Elimination.

Tumor starvation induced by intratumor glucose depletion emerges as a promising strategy for anticancer therapy. However, its antitumor potencies are severely compromised by intrinsic tumor hypoxia, low delivery efficiencies, and undesired off-target toxicity. Herein, a multifunctional cascade bioreactor (HCG), based on the self-assembly of pH-responsive hydroxyethyl starch prodrugs, copper ions, and glucose oxidase (GOD), is engineered, empowered by hyperbaric oxygen (HBO) for efficient cooperative therapy against aggressive breast cancers. Once internalized by tumor cells, HCG undergoes disassembly and releases cargoes in response to acidic tumor microenvironment. Subsequently, HBO activates GOD-catalyzed oxidation of glucose to H2 O2 and gluconic acid by ameliorating tumor hypoxia, fueling copper-catalyzed •OH generation and pH-responsive drug release. Meanwhile, HBO degrades dense tumor extracellular matrix, promoting tumor accumulation and penetration of HCG. Moreover, along with the consumption of glucose and the redox reaction of copper ions, the antioxidant capacity of tumor cells is markedly reduced, collectively boosting oxidative stress. As a result, the combination of HCG and HBO can not only remarkably suppress the growth of orthotopic breast tumors but also restrain pulmonary metastases by inhibiting cancer stem cells. Considering the clinical accessibility of HBO, this combined strategy holds significant translational potentials for GOD-based therapies.

Tumor Microenvironment-Responsive Nanoherb Delivery System for Synergistically Inhibition of Cancer Stem Cells.

Multidrug resistance in cancer stem cells (CSCs) is a major barrier to chemotherapy; hence, developing CSC-specific targeted nanocarriers for efficient drug delivery is critical. In this study, monodisperse hollow-structured MnO2 (H-MnO2) with a mesoporous shell was created for efficient targeted drug delivery. An effective therapeutic compound isoliquiritigenin (ISL) was confirmed to inhibit the lung cancer stem-cell phenotype by natural compound screening based on integrated microfluidic devices. The resultant H-MnO2 showed a high drug-loading content of the potent CSC-targeting compound ISL and near-infrared fluorescent dye indocyanine green (ICG). In addition, H-MnO2 was successively modified with hyaluronic acid (HA) to enhance targeting CSCs with high CD44 expression levels. The H-MnO2@(ICG + ISL)@HA nanocomposites displayed promising chemotherapeutic and photothermal treatment capabilities, as well as NIR-triggered drug release, which showed excellent CSC-killing effects and tumor inhibition efficacy. Meanwhile, the development of the tumor was effectively restrained by NIR-triggered phototherapy and prominent chemotherapy without obvious side effects after tail vein injection of the nanocomposites in vivo. In summary, the prepared nanocomposites accomplished synergistic cancer therapy that targets CSCs, offering a versatile platform for lung cancer diagnosis and treatment.

Novel Synthetic Derivative of Renieramycin T Right-Half Analog Induces Apoptosis and Inhibits Cancer Stem Cells via Targeting the Akt Signal in Lung Cancer Cells

Akt is a key regulatory protein of cancer stem cells (CSCs) and is responsible for cancer aggressiveness and metastasis. Targeting Akt is beneficial for the development of cancer drugs. renieramycin T (RT) has been reported to have Mcl-1 targeting activity, and the study of the structure-activity relationships (SARs) demonstrated that cyanide and the benzene ring are essential for its effects. In this study, novel derivatives of the RT right-half analog with cyanide and the modified ring were synthesized to further investigate the SARs for improving the anticancer effects of RT analogs and evaluate CSC-suppressing activity through Akt inhibition. Among the five derivatives, a compound with a substituted thiazole structure (DH_25) exerts the most potent anticancer activity in lung cancer cells. It has the ability to induce apoptosis, which is accompanied by an increase in PARP cleavage, a decrease in Bcl-2, and a diminishment of Mcl-1, suggesting that residual Mcl-1 inhibitory effects exist even after modifying the benzene ring to thiazole. Furthermore, DH_25 is found to induce CSC death, as well as a decrease in CSC marker CD133, CSC transcription factor Nanog, and CSC-related oncoprotein c-Myc. Notably, an upstream member of these proteins, Akt and p-Akt, are also downregulated, indicating that Akt can be a potential target of action. Computational molecular docking showing a high-affinity interaction between DH_25 and an Akt at the allosteric binding site supports that DH_25 can bind and inhibit Akt. This study has revealed a novel SAR and CSC inhibitory effect of DH_25 via Akt inhibition, which may encourage further development of RT compounds for cancer therapy.

Isophysalin A Inhibits the Stemness of Breast Cancer Cells Possibly via Stat3 and IL-6 Signaling.

Breast cancer stem cells (BCSCs) are involved in carcinogenesis of the breast and contribute to therapeutic resistance. In the present study, we found that isophysalin A acts as a potent cancer stem cell inhibitor and investigated the anti-CSC mechanism of action of isophysalin A on breast cancer. The effect of isophysalin A on BCSCs was examined using a mammosphere formation, a colony formation and a cell migration assay, as well as CD44 (Cluster of differentiation 44)high/CD24 (Cluster of differentiation 24)low analysis, an apoptosis assay, quantitative real-time PCR, western blotting, an electrophoretic mobility shift assay, and a cytokine profiling assay. Isophysalin A inhibited cell proliferation, colony formation, cell migration, CSC formation, and mammosphere proliferation and increased BCSC apoptosis. The subpopulation of CD44high/CD24low was decreased by isophysalin A, which also reduced the DNA binding of Stat3 and the total and nuclear protein expression levels of Stat3 and phosphorylated Stat3. Furthermore, the mRNA and media IL-6/IL-8 levels of the mammosphere were also reduced by isophysalin A. Isophysalin A inhibited the Stat3 and IL-6 signaling pathways and induced CSC death; thus, isophysalin A may be a potential natural inhibitor of BCSCs.