Arrest In Breast Cancer Cells Research Articles

A Novel ASCT2 Inhibitor, C118P, Blocks Glutamine Transport and Exhibits Antitumour Efficacy in Breast Cancer.

The microtubule protein inhibitor C118P shows excellent anti-breast cancer effects. However, the potential targets and mechanisms of C118P in breast cancer remain unknown. Real-time cellular analysis (RTCA) was used to detect cell viability. Apoptosis and the cell cycle were detected by flow cytometry. Computer docking simulations, surface plasmon resonance (SPR) technology, and microscale thermophoresis (MST) were conducted to study the interaction between C118P and alanine-serine-cysteine transporter 2 (ASCT2). Seahorse XF technology was used to measure the basal oxygen consumption rate (OCR). The effect of C118P in the adipose microenvironment was explored using a co-culture model of adipocytes and breast cancer cells and mouse cytokine chip. C118P inhibited proliferation, potentiated apoptosis, and induced G2/M cell cycle arrest in breast cancer cells. Notably, ASCT2 was validated as a C118P target through reverse docking, SPR, and MST. C118P suppressed glutamine metabolism and mediated autophagy via ASCT2. Similar results were obtained in the adipocyte-breast cancer microenvironment. Adipose-derived interleukin-6 (IL-6) promoted the proliferation of breast cancer cells by enhancing glutamine metabolism via ASCT2. C118P inhibited the upregulation of ASCT2 by inhibiting the effect of IL-6 in co-cultures. C118P exerts an antitumour effect against breast cancer via the glutamine transporter ASCT2.

Sanggenon C inhibits proliferation of breast cancer cells and reduces HIF-1α/VEGF pathway activity under hypoxia conditions

Purpose: To evaluate the function and mechanism of sanggenon C (SC) on breast cancer (BC) cells.Methods: The effect of SC on malignant processes of BC was studied through cell counting kit-8, colony formation, flow cytometry, Transwell, wound-healing and western blot experiments. Besides, the related mechanism of action was explored using western blot assay.Results: SC reduced the cell viability of MDA-MB-231 and MCF-7 cells with half-maximal concentration of (IC50) value of 17.09 and 17.32 μM, respectively. SC also decreased the area ratio of colonies in the plate, but increased the apoptosis and G0/G1 phase arrest in both cell lines. Furthermore, SC decreased the number of invasion cells, but elevated the relative wound width of both cells. Moreover, SC treatment neutralized the hypoxia-induced level of HIF-1α/VEGF signaling.Conclusion: SC suppresses proliferation, mobility and invasion, but induces apoptosis and G0/G1 phase arrest in BC cells, as well as deceased HIF-1α/VEGF pathway activity under hypoxia conditions. The findings of this study reveal that SC is a potential agent for BC management.

Modulatory effects of point-mutated IL-32θ (A94V) on tumor progression in triple-negative breast cancer cells.

Breast cancer is a frequently diagnosed cancer and the leading cause of death among women worldwide. Tumor-associated macrophages stimulate cytokines and chemokines, which induce angiogenesis, metastasis, proliferation, and tumor-infiltrating immune cells. Although interleukin-32 (IL-32) has been implicated in the development and modulation of several cancers, its function in breast cancer remains elusive. Mutation of interleukin-32θ (IL-32θ) in the tissues of patients with breast cancer was detected by Sanger sequencing. RT-qPCR was used to detect the mRNA levels of inflammatory cytokines, chemokines, and mediators. The secreted proteins were detected using respective enzyme-linked immunosorbent assays. Evaluation of the inhibitory effect of mutant IL-32θ on proliferation, migration, epithelial-mesenchymal transition (EMT), and cell cycle arrest in breast cancer cells was conducted using MTS assays, migration assays, and Western blotting. A point mutation (281C>T, Ala94Val) was detected in IL-32θ in both breast tumors and adjacent normal tissues, which suppressed the expression of pro-inflammatory factors, EMT factors, and cell cycle related factors. Mutated IL-32θ inhibited the expression of inflammatory factors by regulating the NF-κB pathway. Furthermore, mutated IL-32θ suppressed EMT markers and cell cycle related factors through the FAK/PI3K/AKT pathway. It was inferred that mutated IL-32θ modulates breast cancer progression. Mutated IL-32θ (A94V) inhibited inflammation, EMT, and proliferation in breast cancer by regulating the NF-κB (p65/p50) and FAK-PI3K-GSK3 pathways.

Acenaphthotriazine Thio-triazole Derivatives as Anti-cancer Agents Triggering Cell Cycle Arrest in Breast Cancer Cells

Background: Cancer is one of the most devastating diseases, affecting the lives of millions of people around the world. Introduction: A series of acenaphtho[1,2-e][1,2,4]triazine containing different thiomethyl-1,2,3-triazole derivatives were designed based on a fragment-based and molecular hybridization approach as anti-cancer agents. Methods: Designed compounds were synthesized using cycloaddition condensation followed by click reaction. Cytotoxicity of prepared compounds was evaluated by MTT reduction assay against four different cancer cell lines. Results: The biological evaluation indicated that derivative 6d with para-fluorobenzyl moiety was the most active cytotoxic agent with IC50 values of 70.1, 12.8, 41.5, and 16.0 μM against K562, MOLT-4, HT-29, and MCF-7 cells, respectively. Cell cycle analysis showed that acenaphtho triazine derivatives could induce G0/G1 phase arrest in MCF-7 breast cancer cells. Conclusion: Synthesized derivatives can be ideal candidates for further exploration as anti-cancer agents.

LncRNA MIR17HG Suppresses Breast Cancer Proliferation and Migration as ceRNA to Target FAM135A by Sponging miR-454-3p

Breast cancer is one of the most common malignant tumors in women, and causes a large number of cancer-related deaths. The main cause of death of breast cancer patients is tumor recurrence and metastasis. Recent studies show that lncRNA (Long non-coding RNA) plays an important role in breast cancer. However, the overall biological activity and clinical consequences of the lncRNA MIR17HG in breast cancer remain unclear. Thus, we investigate how the MIR17HG/miR-454-3p network impacts breast cancer cell proliferation and migration. Given the TCGA and Oncomine databases, the researchers evaluated variations in MIR17HG expression for the survival rates of breast cancer patients. The influence of MIR17HG on cell proliferation, migration, cell cycle, and the mRNA expression level of miR-454-3p and FAM135A (family with sequence similarity 135 member A) is identified. Luciferase assay was used to detect the regulatory effect of miR-454-3p on the 3′UTR region of FAM135A, and rescue experiments demonstrated that MIR17HG can up-regulate FAM135A expression by competitively binding miR-454-3p. The effect of FAM135A on the cloning and invasion of MCF-7 cells was detected. MIR17HG expression is reduced in breast cancer tissues, and patients with greater levels of MIR17HG expression have a better prognosis. MIR17HG overexpression caused G2/M arrest in breast cancer cells according to a flow cytometry assay. FAM135A knockdown enhances breast cancer cell proliferation and clone creation, as well as two-dimensional and three-dimensional migratory capacities. Patients with high FAM135A expression in their breast cancer had a better prognosis. These novel findings indicate that MIR17HG may be a potential target for breast cancer. Our findings demonstrated that MIR17HG might suppress breast cancer cell proliferation and migration by sponge miR-454-3p through ceRNA(competing endogenous RNAs) mechanism, indicating that targeting MIR17HG may be a feasible therapeutic candidate for breast cancer.Graphical

Specific Forms of Graphene Quantum Dots Induce Apoptosis and Cell Cycle Arrest in Breast Cancer Cells.

Graphene quantum dots (GQDs), nanomaterials derived from graphene and carbon dots, are highly stable, soluble, and have exceptional optical properties. Further, they have low toxicity and are excellent vehicles for carrying drugs or fluorescein dyes. Specific forms of GQDs can induce apoptosis and could be used to treat cancers. In this study, three forms of GQDs (GQD (nitrogen:carbon = 1:3), ortho-GQD, and meta-GQD) were screened and tested for their potential to inhibit breast cancer cell (MCF-7, BT-474, MDA-MB-231, and T-47D) growth. All three GQDs decreased cell viability after 72 h of treatment and specifically affected breast cancer cell proliferation. An assay for the expression of apoptotic proteins revealed that p21 and p27 were up-regulated (1.41-fold and 4.75-fold) after treatment. In particular, ortho-GQD-treated cells showed G2/M phase arrest. The GQDs specifically induced apoptosis in estrogen receptor-positive breast cancer cell lines. These results indicate that these GQDs induce apoptosis and G2/M cell cycle arrest in specific breast cancer subtypes and could potentially be used for treating breast cancers.

Vorinostat induces G2/M cell cycle arrest in breast cancer cells via upregulation of PTEN.

Breast cancer (BC) is the most common type of cancer in females worldwide. Various approaches were proposed to treat the disease, with no sole agent proved efficient. Thus, understanding the molecular mechanisms of different drugs became mandatory. The present study aimed at evaluating the role of erlotinib (ERL) and vorinostat (SAHA) in inducing apoptosis in breast cancer cells. The role of these drugs was assessed also on the expression profile of some cancer-related genes; PTEN, P21, TGF, and CDH1. In the present study, breast cancer cells (MCF-7) and MDA-MB-231 along with human amniotic cells (WISH) were treated with two concentrations (50, and 100 µM) of erlotinib (ERL) and vorinostat (as known as SAHA) for 24 h. Cells were harvested for downstream analysis. DNA content and apoptosis were analyzed by flow cytometer, and qPCR was performed to assess the expression of different cancer-related genes. The results indicated that ERL and SAHA arrested both breast cancer cells at the G2/M phase after 24 h compared to normal cells and control. For apoptosis, BC cells showed an elevated level of total apoptosis (early and late) increasing the concentrations of the two applied drugs, with the most effective concentration of ERL at 100 µM in the 24-h treatment. In the control cells, SAHA was proved to be the most effective drug at a concentration of 100 µM with a percentage of apoptosis ranging from 1.7-12% in the 24-h treatment. Necrosis also was dose-dependent in the two breast cancer cell lines used. We further evaluated the expression profiles of PTEN, P21, TGF-β, and CDH1. In MCF-7, data indicated that for TGF-β, PTEN, and P21, the most effective treatment was SAHA at a concentration of 100 µM, while for CDH1, the most effective concentration was ERL at 100 µM. A similar profile was observed in MDA-MB-232, where for TGF-β, PTEN, and P21, the most effective treatment was SAHA at a concentration of 100 µM, while for CDH1, the most effective concentration was SAHA at 50 µM. Our results shed some light on the role of ERL and SAHA in regulating the expression of cancer-related genes, though these data need further investigation.

Doxorubicin-Loaded Iron Oxide Nanoparticles Induce Oxidative Stress and Cell Cycle Arrest in Breast Cancer Cells

Cancer is one of the most common diseases nowadays and derives from the uncontrollable growth of a single cell. Magnetic nanoparticles (NpMag) offer various possibilities for use in the biomedical area, including drug delivery mediated by magnetic fields. In the current study, we evaluated the in vitro effects of iron-oxide magnetic nanoparticles conjugated with the antitumor drug doxorubicin (Dox) on human breast cancer cells. Our results revealed that magnetic nanoparticles with Dox (NpMag+Dox) induce cellular redox imbalance in MCF-7 cells. We also demonstrate that iron-oxide nanoparticles functionalized with Dox induce oxidative stress evidenced by DNA damage, lipid peroxidation, cell membrane disruption, and loss of mitochondria potential. As a result, NpMag+Dox drives MCF-7 cells to stop the cell cycle and decrease cell migration. The association of NpMg+Dox induced a better delivery of Dox to MCF cells, mainly in the presence of a magnetic field, increasing the death of MCF cells which might reduce the toxicity for healthy cells providing a better efficacy for the treatment. Thus, iron-oxide nanoparticles and doxorubicin conjugated may be candidate for anticancer therapy.

WXJ-202, a novel Ribociclib derivative, exerts antitumor effects against breast cancer through CDK4/6.

Cyclin-dependent kinases 4 and 6 (CDK4/6) are key regulatory proteins in the cell division and proliferative cycle in humans. They are overactive in many malignant tumors, particularly in triple-negative breast cancer (TNBC). Inhibition of CDK4/6 targets can have anti-tumor effects. Here, we designed and synthesized a novel derivative of Ribociclib that could affect CDK4/6, named WXJ-202. This study aimed to investigate the effects of compound WXJ-202 on proliferation, apoptosis, and cell cycle arrest in human breast cancer cell lines and their molecular mechanisms. We assayed cell viability with methyl thiazolyl tetrazolium (MTT) assay. Clone formation, migration, and invasion ability were assayed by clone formation assay, wound healing assay, and transwell invasion assay. The effect of compound WXJ-202 on apoptosis and cell cycle was detected by flow cytometry analysis. Western blotting was performed to detect the expression of proteins related to the CDK4/6-Rb-E2F pathway. The anti-cancer effects were studied in vivo transplantation tumor models. WXJ-202 was shown to inhibit cell proliferation, colony formation, migration, and invasion, as well as induce apoptosis and cycle arrest in breast cancer cells. The levels of proteins related to the CDK4/6-Rb-E2F pathway, such as CDK4, CDK6, and p-Rb, were decreased. Finally, studies had shown that compound WXJ-202 exhibited significant anti-tumor activity in transplantation tumor models. In this research, the compound WXJ-202 was shown to have better anti-tumor cell proliferative effects and could be used as a potential candidate against TNBC tumors.

Combinatorial effect of diclofenac with piperine and D-limonene on inducing apoptosis and cell cycle arrest of breast cancer cells

Objective: To investigate the potential synergistic activity of diclofenac with piperine and D-limonene in inducing apoptosis and cell cycle arrest in breast cancer MCF-7 cells.Methods: Molecular docking study was conducted to evaluate the binding affinity of diclofenac with piperine and D-limonene against p53, Bax, and Bcl-2. The MTT assay was used to determine IC50, and the Chou-Talay method was used to determine the synergistic concentration of the combination treatment of diclofenac plus piperine and diclofenac plus D-limonene. Apoptosis detection, cell cycle arrest, reactive oxygen species production, and mitochondrial membrane potential were also investigated.Results: Diclofenac, piperine, and D-limonene showed potent binding affinity for p53, Bax, and Bcl-2. Diclofenac plus piperine and diclofenac plus D-limonene enhanced the formation of reactive oxygen species, which also had an effect on the mitochondrial membrane's integrity and caused DNA fragmentation. Diclofenac plus piperine and diclofenac plus D-limonene arrested the cells in the sub-G0 phase while drastically lowering the percentage of cells in the G2/M phase. Furthermore, the elevated apoptosis in the combined therapy was confirmed by annexin V/propidium iodide staining.Conclusions: The combined therapy prominently enhanced the anti-proliferative and apoptotic effects on MCF-7 cells compared with treatment with diclofenac, piperine, and D-limonene alone.

MiR-144 as a novel biomarker in breast cancer diagnosis and treatment

Exosomes naturally carry the biomolecules in the body; they perform this task efficiently without compromising the immune system and by breaking through all the biological barriers, so they can be the best choice for designing and introducing a drug and gene transfer system. Extraction of the exosomes from the cell culture medium was performed by precipitation with an Exoquick kit solution. Nanoparticle specificity analysis was performed using scanning electron microscopy and dynamic light scattering. Trizol reagent (Invitrogen) was used for RNA extraction. Single-strand cDNA synthesis was performed from the miRNA and RT-PCR. Data were analyzed using a threshold cycle comparative method and cell cycle analysis using flow cytometry. Exosomes containing miR-144 can dramatically decrease the expression level of crucial TGF-β pathway genes, SMAD4 and TGF-βR2, in breast cancer cells. Botulinum toxin A inhibits cancer cell growth by inhibiting the TGF-β pathway. The simultaneous combination of engineered exosomes containing miR-144 and bacterial botulinum toxin A has increased effects on inhibiting the TGF-β signaling pathway. It causes cell cycle arrest in breast cancer cells. The present study's findings showed that overexpression of miR-144 in breast tumor cells results in the packaging of miRNA in exosomes derived from these cells. As a result, the exosomal platform for nucleic acid transfer to the cell appears to be an effective transducer for gene transfer to the cell. It could be used as a suitable adjunct to cancer therapeutic studies. Keywords: Breast cancer, botulinum toxin A, exosome, miRNA, biomarker.

Hsa_circ_0069094 positively regulates the expression of oncogenic ZNF217 by competitively targeting miR-758-3p to promote the development of breast cancer.

To investigate the functions and potential mechanisms of hsa_circ_0069094 in this cancer. The expression of hsa_circ_0069094, zinc finger protein 217 (ZNF217) and microRNA-758-3p (miR-758-3p) was detected by quantitative polymerase chain reaction (qPCR), and the protein level of ZNF217 was detected by western blot. Cell proliferation was assessed using cell counting kit-8 (CCK-8) assay and colony formation assay. Cell cycle progression and cell apoptosis were determined using flow cytometry assay. Cell invasion and cell migration were monitored using transwell assay and wound healing assay. The protein levels of apoptosis-related proteins were quantified by western blot. The putative relationship between miR-758-3p and hsa_circ_0069094 and ZNF217 was confirmed using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Xenograft model was constructed in mice to explore the role of hsa_circ_0069094 on solid tumor growth.Hsa_circ_0069094 and ZNF217 were highly expressed, while miR-758-3p was poorly expressed in tissues and cells of breast cancer. Hsa_circ_0069094 knockdown or ZNF217 knockdown inhibited cell proliferation, invasion and migration and induced cell apoptosis and cell cycle arrest in breast cancer cells. The inhibitory effects of hsa_circ_0069094 knockdown on cell malignant behaviors were abolished by ZNF217 overexpression. Hsa_circ_0069094 competed with ZNF217 for the binding site of miR-758-3p, and hsa_circ_0069094 positively regulated ZNF217 expression by competitively binding to miR-758-3p. Hsa_circ_0069094 knockdown also blocked solid tumor growth in mice. Collectively, Hsa_circ_0069094 played oncogenic effects in breast cancer by activating the expression of ZNF217 via competitively binding to miR-758-3p, which might be a novel strategy for breast cancer suppression.

Viscoelastic Liquid Matrix with Faster Bulk Relaxation Time Reinforces the Cell Cycle Arrest Induction of the Breast Cancer Cells via Oxidative Stress

The reactivating of disseminated dormant breast cancer cells in a soft viscoelastic matrix is mostly correlated with metastasis. Metastasis occurs due to rapid stress relaxation owing to matrix remodeling. Here, we demonstrate the possibility of promoting the permanent cell cycle arrest of breast cancer cells on a viscoelastic liquid substrate. By controlling the molecular weight of the hydrophobic molten polymer, poly(ε-caprolactone-co-D,L-lactide) within 35-63 g/mol, this study highlights that MCF7 cells can sense a 1000 times narrower relaxation time range (80-290 ms) compared to other studies by using a crosslinked hydrogel system. We propose that the rapid bulk relaxation response of the substrate promotes more reactive oxygen species generation in the formed semi-3D multicellular aggregates of breast cancer cells. Our finding sheds light on the potential role of bulk stress relaxation in a viscous-dominant viscoelastic matrix in controlling the cell cycle arrest depth of breast cancer cells.

The Reduced Graphene Oxide (rGO) Induces Apoptosis, Autophagy and Cell Cycle Arrest in Breast Cancer Cells.

Reduced graphene oxide (rGO) has already been reported as a potential cytostatic agent in various cancers. However, the mechanisms underlying rGO’s cytotoxicity are still insufficiently understood. Thus, the aim of the study was to investigate the molecular and cellular effects of rGO in breast cancer. Given this, two cell lines, MDA-MB-231 and ZR-75-1, were analyzed using MTT test, flow cytometry and Western blot assay. Incubation with rGO resulted in a multitude of effects, including the stimulation of autophagy, cell cycle arrest and, finally, the apoptotic death of cancer cells. Notably, rGO had minimal effect on normal human fibroblasts. Apoptosis in cancer cells was accompanied by decreased mitochondrial membrane potential, the deregulated expression of mitochondrial proteins and the activation of caspase 9 and caspase 3, suggesting that rGO predominantly induced apoptosis via intrinsic pathway. The analysis of LC3 protein expression revealed that rGO also caused autophagy in breast cancer cells. Moreover, rGO treatment resulted in cell cycle arrest, which was accompanied by deregulated p21 expression. Altogether, rGO seems to have multidirectional cytostatic and cytotoxic effects in breast cancer cells, making it a promising agent worthy of further investigation.

Integrating UPLC-HR-MS/MS, Network Pharmacology, and Experimental Validation to Uncover the Mechanisms of Jin'gan Capsules against Breast Cancer.

In the theory of traditional Chinese medicine (TCM), “liver-qi” stagnation and heat-induced toxicity represent the main etiologies of breast cancer. Recently, several TCMs with heat-clearing and detoxification efficacy have shown inhibitory effects on breast cancer. Jin’gan capsules (JGCs), initially approved to treat colds in China, are a heat-clearing and detoxification TCM formula. However, the anticancer activity of JGCs against breast cancer and its underlying mechanisms remain unclear. First, we assessed the antiproliferative activity of JGCs in breast cancer cell lines and evaluated their effects on cell apoptosis and the cell cycle by flow cytometry. Furthermore, we identified the potential bioactive components of JGCs and their corresponding target genes and constructed a bioactive compound–target interaction network by ultra-performance liquid chromatography–high-resolution tandem mass spectrometry (UPLC-HR-MS/MS) and network pharmacology analysis. Finally, the underlying mechanism was investigated through gene function enrichment analysis and experimental validation. We found that JGCs significantly inhibited breast cancer cell growth with IC50 values of 0.56 ± 0.03, 0.16 ± 0.03, and 0.94 ± 0.09 mg/mL for MDA-MB-231, MDA-MB-468, and MCF-7, respectively. In addition, JGC treatment dramatically induced apoptosis and S phase cell cycle arrest in breast cancer cells. Western blot analysis confirmed that JGCs could regulate the protein levels of apoptosis- and cell cycle-related genes. Utilizing UPLC-HR-MS/MS analysis and network pharmacology, we identified 7 potential bioactive ingredients in JGCs and 116 antibreast cancer targets. Functional enrichment analysis indicated that the antitumor effects of JGCs were strongly associated with apoptosis and the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway. Western blot analysis validated that JGC treatment markedly decreased the expression levels of p-JAK2, p-STAT3, and STAT3. Our findings suggest that JGCs suppress breast cancer cell proliferation and induce cell cycle arrest and apoptosis partly by inhibiting the JAK2/STAT3 signaling pathway, highlighting JGCs as a potential therapeutic candidate against breast cancer.

In Vitro Growth Inhibition, Caspase-Dependent Apoptosis, and S and G2/M Phase Arrest in Breast Cancer Cells Induced by Fluorine-Incorporated Gold I Compound, Ph3PAu[SC(OMe)=NC6H4F-3

Gold-based anticancer compounds have been attracting increasing research interest due to their ability to kill cancer cells resistant to platinum-based compounds. Gold I- and gold III-based complexes have shown satisfactory anticancer activities. In this study, two new fluorine-incorporated gold (I) compounds such as Ph3PAu[SC(OMe)=NC6H4F-3] and DPPFeAu2[(SC(OMe)=NC6H4F-3)]2 were evaluated for their in vitro activities against human breast cancer cell lines, primary breast cancer cells, and breast cancer stem cells (parental breast cancer stem cells, BCSC-P, and breast cancer stem cells, BCSC). Assays for growth inhibition and cytotoxicity, including real-time cell analysis, were carried out to screen effective antibreast cancer compounds. In addition, further in vitro assays such as apoptosis, caspase 3/7 activity, and cell cycle analysis were performed to observe the action and mechanism of killing breast cancer cells by the selected gold I compound, Ph3PAu[SC(OMe)=NC6H4F-3]. The gold (I) compound, Ph3PAu[SC(OMe)=NC6H4F-3], showed low toxicity to H9c2 normal cells and significant growth inhibition in MDA-MB-231 and MCF-7 cells, primary breast cancer cells, and breast cancer stem cells (BCSC-P and BCSC). The IC50 doses of the gold (I) compound Ph3PAu[SC(OMe)=NC6H4F-3] against the breast cancer cell lines MDA-MB-231 and MCF-7 were approximately 6-fold lower than that of cisplatin (cis-diamineplatinum (II) dichloride, CDDP). Moreover, the compound Ph3PAu[SC(OMe)=NC6H4F-3] induced caspase 3/7-dependent apoptosis and cell cycle arrest at S and G2/M phases. Ph3PAu[SC(OMe)=NC6H4F-3], a gold (I) compound incorporated with fluorine, is a potential candidate for the treatment of breast cancer.

YTHDF1 promotes breast cancer progression by facilitating FOXM1 translation in an m6A-dependent manner

BackgroundN6-methyladenosine (m6A) is the most common post-transcriptional modification at the RNA level. However, the exact molecular mechanisms of m6A epigenetic regulation in breast cancer remain largely unknown and need to be fully elucidated.Methods The integrating bioinformatics analyses were used to screen clinical relevance and dysregulated m6A “reader” protein YTHDF1 in breast cancer from TCGA databases, which was further validated in a cohort of clinical specimens. Furthermore, functional experiments such as the CCK-8 assay, EdU assay, wound healing assay, transwell invasion assay and cell cycle assay were used to determine the biological role of YTHDF1 in breast cancer. RIP, m6A-IP, and CLIP assays were used to find the target of YTHDF1 and further verification by RT-qPCR, western blot, polysome profiling assay. The protein–protein interaction between YTHDF1 and FOXM1 was detected via co-immunoprecipitation.ResultsOur study showed that YTHDF1 was overexpressed in breast cancer cells and clinical tissues specimens. At the same time, the high expression level of YTHDF1 was positively correlated with tumor size, lymph node invasion, and distant metastasis in breast cancer patients. YTHDF1 depletion repressed the proliferation, invasion and epithelial-mesenchymal transformation (EMT) and induced G0/G1 phase cell cycle arrest of breast cancer cells in vitro and in vivo. We also demonstrated that FOXM1 is a target of YTHDF1. Through recognizing and binding to the m6A-modified mRNA of FOXM1, YTHDF1 accelerated the translation process of FOXM1 and promoted breast cancer metastasis. Whereas overexpression of FOXM1 in breast cancer cells partially counteracted the tumor suppressed effects caused by YTHDF1 silence, which further verified the regulatory relationship between YTHDF1 and FOXM1.ConclusionOur study reveals a novel YTHDF1/FOXM1 regulatory pathway that contributes to metastasis and progression of breast cancer, suggesting that YTHDF1 might be applied as a potential biomarker and therapeutic target. That also advances our understanding of the tumorigenesis for breast cancer from m6A epigenetic regulation.

Conjugation of Palbociclib with MHI-148 Has an Increased Cytotoxic Effect for Breast Cancer Cells and an Altered Mechanism of Action.

The CDK4/6 inhibitor palbociclib, combined with endocrine therapy, has been shown to be effective in postmenopausal women with estrogen receptor-positive, HER2-negative advanced or metastatic breast cancer. However, palbociclib is not as effective in the highly aggressive, triple-negative breast cancer that lacks sensitivity to chemotherapy or endocrine therapy. We hypothesized that conjugation of the near-infrared dye MHI-148 with palbociclib can produce a potential theranostic in triple-negative, as well as estrogen receptor-positive, breast cancer cells. In our study, the conjugate was found to have enhanced activity in all mammalian cell lines tested in vitro. However, the conjugate was cytotoxic and did not induce G1 cell cycle arrest in breast cancer cells, suggesting its mechanism of action differs from the parent compound palbociclib. The study highlights the importance of investigating the mechanism of conjugates of near-infrared dyes to therapeutic compounds, as conjugation can potentially result in a change of mechanism or target, with an enhanced cytotoxic effect in this case.

The Optimized Formulation of Tamoxifen-Loaded Niosomes Efficiently Induced Apoptosis and Cell Cycle Arrest in Breast Cancer Cells.

The aim, as proof of concept, was to optimize niosomal formulations of tamoxifen in terms of size, morphology, encapsulation efficiency, and release kinetics for further treatment of the breast cancer (BC). Different assays were carried out to evaluate the pro-apoptotic and cytotoxicity impact of tamoxifen-loaded niosomes in two BC cells, MDA-MB-231 and SKBR3. In this study, tamoxifen was loaded in niosomes after optimization in the formulation. The formulation of niosomes supported maximized drug entrapment and minimized their size. The novel formulation showed improvement in storage stability, and after 60 days only, small changes in size, polydispersity index, and drug entrapment were observed. Besides, a pH-dependent release pattern of formulated niosomes displayed slow release at physiological pH (7.4) and a considerable increase of release at acidic pH (5.4), making them a promising candidate for drug delivery in the BC treatment. The cytotoxicity study exhibited high biocompatibility with MCF10A healthy cells, while remarkable inhibitory effects were observed after treatment of cancerous lines, MDA-MB-231, and SKBR3 cells. The IC50 values for the tamoxifen-loaded niosomes were significantly less than other groups. Moreover, treatment with drug-loaded niosomes significantly changed the gene expression pattern of BC cells. Statistically significant down-regulation of cyclin D, cyclin E, VEGFR-1, MMP-2, and MMP-9 genes and up-regulation of caspase-3 and caspase-9 were observed. These results were in correlation with cell cycle arrest, lessoned migration capacity, and increased caspase activity and apoptosis induction in cancerous cells. Optimization in the formulation of tamoxifen-loaded niosomes can make them a novel candidate for drug delivery in BC treatment.

Sulfonamide metformin derivatives induce mitochondrial-associated apoptosis and cell cycle arrest in breast cancer cells

Metformin, an oral anti-diabetic drug, has attracted scientific attention due to its anti-cancer effects. This biguanide exerts preventive effects against cancer, and interferes with cancer-promoting signaling pathways at the cellular level. However, the direct cytotoxic or anti-proliferative effect of the drug is observed at very high concentrations, often exceeding 5–10 mM. This paper presents the synthesis of eight novel sulfonamide-based biguanides with improved cellular uptake in two breast cancer cell lines (MCF-7 and MDA-MB-231), and evaluates their effects on cancer cell growth.The synthesized sulfonamide-based analogues of metformin (1–5) were efficiently taken up in MCF-7 and MDA-MB-231 cells, and were characterized by stronger cytotoxic properties than those of metformin. Generally, compounds were more effective in MCF-7 than in MDA-MB-231. Compound 2, with an n-octyl chain, was the most active molecule with IC50 = 114.0 μmol/L in MCF-7 cells. The cytotoxicity of compound 2 partially results from its ability to induce early and late apoptosis. Increased intracellular reactive oxygen species (ROS) production and reduced mitochondrial membrane potential suggest that compound 2 promotes mitochondrial dysfunction and activates the mitochondrial-associated apoptosis-signaling pathway. In addition, compound 2 was also found to arrest cell cycle in the G0/G1 and G2/M phase and significantly inhibit cancer cell migration.In conclusion, this study supports the hypothesis that improved transporter-mediated cellular uptake of potential drug molecule is accompanied by its increased cytotoxicity. Therefore, compound 2 is a very good example of how chemical modification of a biguanide scaffold can affect its biological properties and improve anti-neoplastic potential.