Self-Assembly of Cholesterol-Doxorubicin and TPGS into Prodrug-Based Nanoparticles with Enhanced Cellular Uptake and Lysosome-Dependent Pathway in Breast Cancer Cells

Developing new easy-to-prepare functional drug delivery nanosystems with good storage stability, low hemotoxicity, as well as controllable drug delivery property, has attracted great attention in recent years. In this work, a cholesterol-based prodrug nanodelivery system is prepared by self-assembly of cholesterol-doxorubicin prodrug conjugates (Chol-Dox) and tocopherol polyethylene glycol succinate (TPGS) using thin-film hydration method. The Chol-Dox/TPGS assemblies (molar ratio 2:1, 1:1, and 1:2) are able to form nanoparticles with average hydrodynamic diameter of ≈140–214 nm, surface zeta potentials of ≈−24.2–−0.3 mV, and remarkable solution stability in 0.1 m PBS, 16 days). The Chol-Dox/TPGS assemblies show low hemotoxicity and different cytotoxicity profiles in breast cancer cells (MCF-7 and MDA-MB-231), which are largely dependent on the molar ratio of Chol-Dox and TPGS. The Chol-Dox/TPGS assemblies tend to enter into MCF-7 and MDA-MB-231 cells through non-Clathrin-mediated multiple endocytosis and lysosome-dependent uptake pathways, moreover, these nanoassemblies demonstrate lysosome-dependent intracellular localization, which is different from that of free DOX (nuclear localization). The results demonstrate that the Chol-Dox/TPGS assemblies are promising cholesterol-based prodrug nanomaterials for breast cancer chemotherapy. Practical Applications: This work demonstrates a lipid prodrug-based nanotherapeutic system. Herein the Chol-Dox/TPGS nanoassemblies could serve as promising and controllable cholesterol-based prodrug nanomaterials/nano-formulations for potential breast cancer chemotherapy.     

Docosahexaenoic Acid Incorporation Is Not Affected by Doxorubicin Chemotherapy in either Whole Cell or Lipid Raft Phospholipids of Breast Cancer Cells in vitro and Tumor Phospholipids in vivo

To better understand how docosahexaenoic acid (DHA) improves the effects of doxorubicin (DOX), we examined DHA ± DOX on changes in whole cell and lipid raft phospholipids (PL) of MDA-MB-231 and MCF-7 breast cancer cells. We sought to confirm whether the relative changes in PL DHA content of MDA-MB-231 cells could be extended to PL from MDA-MB-231 tumors grown in mice fed a DHA supplemented diet ±DOX. Treatment with DHA did not change PL composition yet DOX increased the proportion of phosphatidylserine in MCF-7 cell lipid rafts by two-fold (p < 0.001). Regardless of DOX, the relative percent incorporation of DHA was higher in MDA-MB-231 cells compared to MCF-7 cells in phosphatidylserine, phosphatidylethanolamine, and phosphatidylcholine (whole cell and lipid rafts); and higher in phosphatidylethanolamine vs. phosphatidylcholine (4.4-fold in MCF-7 and 6-fold in MDA-MB-231 cells respectively). DHA treatment increased eicosapentaenoic acid and docosapentaenoic acid in MDA-MB-231 cells but not MCF-7 cells. Increased DHA content in MDA-MB-231 cells, MCF-7 cells, and MDA-MB-231 tumors in all PL moieties (except sphingomyelin) corresponded with reduced arachidonic acid (p < 0.05). Feeding mice 2.8% (w/w of fat) DHA ± DOX increased tumor necrotic regions (p < 0.05). This study established differential incorporation of DHA into whole cell and lipid rafts between human breast cancer cell lines. However, within each cell line, this incorporation was not altered by DOX confirming that DOX does not change membrane lipid composition. Furthermore, our findings indicate that membrane changes observed in vitro are translatable to in vivo changes and that DHA + DOX could contribute to the anticancer effects through increased necrosis.     

Super Magnetic Niosomal Nanocarrier as a New Approach for Treatment of Breast Cancer: A Case Study on SK-BR-3 and MDA-MB-231 Cell Lines

In the present study, a magnetic niosomal nanocarrier for co-delivery of curcumin and letrozole into breast cancer cells has been designed. The magnetic NiCoFe₂O₄ core was coated by a thin layer of silica, followed by a niosomal structure, allowing us to load letrozole and curcumin into the silica layer and niosomal layer, respectively, and investigate their synergic effects on breast cancer cells. Furthermore, the nanocarriers demonstrated a pH-dependent release due to the niosomal structure at their outer layer, which is a promising behavior for cancer treatment. Additionally, cellular assays revealed that the nanocarriers had low cellular uptake in the case of non-tumorigenic cells (i.e., MCF-10A) and related high viability but high cellular uptake in cancer cell lines (i.e., MDA-MB-231 and SK-BR-3) and related low viability, which is evidenced in their high cytotoxicity against different breast cancer cell lines. The cytotoxicity of the letrozole/curcumin co-loaded nanocarrier is higher than that of the aqueous solutions of both drugs, indicating their enhanced cellular uptake in their encapsulated states. In particular, NiCoFe₂O₄@L-Silica-L@C-Niosome showed the highest cytotoxicity effects on MDA-MB-231 and SK-BR-3 breast cancer cells. The observed cytotoxicity was due to regulation of the expression levels of the studied genes in breast cancer cells, where downregulation was observed for the Bcl-2, MMP 2, MMP 9, cyclin D, and cyclin E genes while upregulation of the expression of the Bax, caspase-3, and caspase-9 genes was observed. The flow cytometry results also revealed that NiCoFe₂O₄@L-Silica-L@C-Niosome enhanced the apoptosis rate in both MDA-MB-231 and SK-BR-3 cells compared to the control samples. The findings of our research show the potential of designing magnetic niosomal formulations for simultaneous targeted delivery of both hydrophobic and hydrophilic drugs into cancer cells in order to enhance their synergic chemotherapeutic effects. These results could open new avenues into the future of nanomedicine and the development of theranostic agents.     

Involvement of the ERK/HIF-1α/EMT Pathway in XCL1-Induced Migration of MDA-MB-231 and SK-BR-3 Breast Cancer Cells

Chemokine–receptor interactions play multiple roles in cancer progression. It was reported that the overexpression of X-C motif chemokine receptor 1 (XCR1), a specific receptor for chemokine X-C motif chemokine ligand 1 (XCL1), stimulates the migration of MDA-MB-231 triple-negative breast cancer cells. However, the exact mechanisms of this process remain to be elucidated. Our study found that XCL1 treatment markedly enhanced MDA-MB-231 cell migration. Additionally, XCL1 treatment enhanced epithelial–mesenchymal transition (EMT) of MDA-MB-231 cells via E-cadherin downregulation and upregulation of N-cadherin and vimentin as well as increases in β-catenin nucleus translocation. Furthermore, XCL1 enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Notably, the effects of XCL1 on cell migration and intracellular signaling were negated by knockdown of XCR1 using siRNA, confirming XCR1-mediated actions. Treating MDA-MB-231 cells with U0126, a specific mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, blocked XCL1-induced HIF-1α accumulation and cell migration. The effect of XCL1 on cell migration was also evaluated in ER^-/HER2⁺ SK-BR-3 cells. XCL1 also promoted cell migration, EMT induction, HIF-1α accumulation, and ERK phosphorylation in SK-BR-3 cells. While XCL1 did not exhibit any significant impact on the matrix metalloproteinase (MMP)-2 and -9 expressions in MDA-MB-231 cells, it increased the expression of these enzymes in SK-BR-3 cells. Collectively, our results demonstrate that activation of the ERK/HIF-1α/EMT pathway is involved in the XCL1-induced migration of both MDA-MB-231 and SK-BR-3 breast cancer cells. Based on our findings, the XCL1–XCR1 interaction and its associated signaling molecules may serve as specific targets for the prevention of breast cancer cell migration and metastasis.     

Synthesis and Anticancer Activity of Tertiary Amides of Salinomycin and Their C20-oxo Analogues

The polyether ionophore salinomycin ( SAL ) has captured much interest because of its potent activity against cancer cells and cancer stem cells. Our previous studies have indicated that C1/C20 double-modification of SAL is a useful strategy to generate diverse agents with promising biological activity profiles. Thus, herein we describe the synthesis of a new class of SAL analogues that combine key modifications at the C1 and C20 positions. The activity of the obtained SAL derivatives was evaluated using primary acute lymphoblastic leukemia, human breast adenocarcinoma and normal mammary epithelial cells. One single- [N,N-dipropyl amide of salinomycin ( 5 a )] and two novel double-modified analogues [N,N-dipropyl amide of C20-oxosalinomycin ( 5 b ) and piperazine amide of C20-oxosalinomycin ( 13 b )] were found to be more potent toward the MDA-MB-231 cell line than SAL or its C20-oxo analogue 2 . When select analogues were tested against the NCI-60 human tumor cell line panel, 4 a [N,N-diethyl amide of salinomycin] showed particular activity toward the ovarian cancer cell line SK-OV-3. Additionally, both SAL and 2 were found to be potent ex vivo against human ER/PR⁺, Her2⁻ invasive mammary carcinoma, with 2 showing minimal toxicity toward normal epithelial cells. The present findings highlight the therapeutic potential of SAL derivatives for select targeting of different cancer types.     

Ruthenium(II)–Arene Thiocarboxylates: Identification of a Stable Dimer Selectively Cytotoxic to Invasive Breast Cancer Cells

Ru^II-arene complexes provide a versatile scaffold for novel anticancer drugs. Seven new Ru^II-arene-thiocarboxylato dimers were synthesized and characterized. Three of the complexes ( 2 a , b and 5 ) showed promising antiproliferative activities in MDA-MB-231 (human invasive breast cancer) cells, and were further tested in a panel of fifteen cancerous and noncancerous cell lines. Complex 5 showed moderate but remarkably selective activity in MDA-MB-231 cells (IC₅₀=39±4 μm Ru). Real-time proliferation studies showed that 5 induced apoptosis in MDA-MB-231 cells but had no effect in A549 (human lung cancer, epithelial) cells. By contrast, 2 a and b showed moderate antiproliferative activity, but no apoptosis, in either cell line. Selective cytotoxicity of 5 in aggressive, mesenchymal-like MDA-MB-231 cells over many common epithelial cancer cell lines (including noninvasive breast cancer MCF-7) makes it an attractive lead compound for the development of specifically antimetastatic Ru complexes with low systemic toxicity.     

DN-ALK2对人乳腺癌细胞MDA-MB-231增殖、迁移和侵袭能力的影响

目的探讨DN-ALK2对人乳腺癌细胞MDA-MB-231增殖、迁移和侵袭能力的影响。方法 RT-PCR法检测MDA-MB-231细胞中ALK2基因mRNA的转录;分别以腺病毒DN-ALK2和RFP感染MDA-MB-231细胞,并设空白对照组,通过MTT法、平板集落形成试验、细胞划痕试验及Transwell侵袭试验检测细胞的增殖、集落形成、迁移及侵袭能力。结果 MDA-MB-231细胞中内源性表达ALK2。腺病毒DN-ALK2和RFP感染MDA-MB-231细胞36 h后,荧光表达量一致,约为70%。MDA-MB-231/DN-ALK2细胞中高表达DN-ALK2。与MDA-MB-231/RFP组相比,MDA-MB-231/DN-ALK2组细胞的增殖活力、集落形成率及划痕愈合率均显著降低(P<0.05),穿膜细胞数也明显减少(P<0.05);而MDA-MB-231/RFP组与空白对照组比较,差异无统计学意义(P>0.05)。结论DN-ALK2可以在体外抑制乳腺癌MDA-MB-231细胞的增殖、迁移与侵袭。     

FOXM1 Inhibitors as Potential Diagnostic Agents: First Generation of a PET Probe Targeting FOXM1 To Detect Triple-Negative Breast Cancer in vitro and in vivo

The FOXM1 protein controls the expression of essential genes related to cancer cell cycle progression, metastasis, and chemoresistance. We hypothesize that FOXM1 inhibitors could represent a novel approach to develop ¹⁸F-based radiotracers for Positron Emission Tomography (PET). Therefore, in this report we describe the first attempt to use ¹⁸F-labeled FOXM1 inhibitors to detect triple-negative breast cancer (TNBC). Briefly, we replaced the original amide group in the parent drug FDI-6 for a ketone group in the novel AF-FDI molecule, to carry out an aromatic nucleophilic (¹⁸F)-fluorination. AF-FDI dissociated the FOXM1-DNA complex, decreased FOXM1 levels, and inhibited cell proliferation in a TNBC cell line (MDA-MB-231). [¹⁸F]AF-FDI was internalized in MDA-MB-231 cells. Cell uptake inhibition experiments showed that AF-FDI and FDI-6 significantly decreased the maximum uptake of [¹⁸F]AF-FDI, suggesting specificity towards FOXM1. [¹⁸F]AF-FDI reached a tumor uptake of SUV=0.31 in MDA-MB-231 tumor-bearing mice and was metabolically stable 60 min post-injection. These results provide preliminary evidence supporting the potential role of FOXM1 to develop PET radiotracers.     

Selective Delivery of Doxorubicin to EGFR+ Cancer Cells by Cetuximab–DNA Conjugates

Doxorubicin is a hydrophobic anticancer drug that has poor selectivity, due to the lack of active targeting capability. Here, learning lessons from the success of antibody–drug conjugates, we have designed a new doxorubicin delivery system without conjugating doxorubicin to antibody directly. In this setup, cetuximab, an antibody that targets the epidermal growth factor receptor (EGFR) in cancer cells, was conjugated to a single-stranded DNA with a carefully designed sequence in a site-selective manner by using the DNA-templated protein conjugation (DTPC) method. The DNA duplex in the conjugates serves as a carrier of doxorubicin through noncovalent intercalation, and cetuximab functions as the targeting agent; this could drastically decrease systemic toxicity and potentially avoid under- or overdosing. The size of conjugates loaded with doxorubicin was about 8.77 or 16.61 nm when characterized by dynamic light scattering and atomic force microscopy, respectively. In vitro cytotoxicity and selective cancer cell killing was investigated against two EGFR⁺ cell lines (KB and MDA-MB-231) and one EGFR⁻ cell line (NIH-3T3). Cytotoxicity and flow cytometry data showed that doxorubicin loaded in cetuximab–DNA conjugates was more potent in terms of cell cytotoxicity than free doxorubicin in EGFR-overexpressed cell lines, thus suggesting that the conjugates were more selectively and easily taken up into cells, followed by rapid release of doxorubicin from the system into the cytoplasm from endosomes.     

Carboxymethylinulin–Chitosan Nanoparticles for the Delivery of Antineoplastic Mitoxantrone

Mitoxantrone (MTX) is an antineoplastic agent whose use is limited by serious side effects on non‐neoplastic cells. The aim of this study was the development of a new drug release system using an ionotropic gelation technique for microencapsulation of MTX in chitosan–carboxymethylinulin nanoparticles (CCInp), followed by evaluation of their cytotoxic effects on neoplastic MDA‐MB‐231 and non‐neoplastic NIH3T3 cell lines. The CCInp were prepared through a new reliable method for easy functionalization of both inulin and chitosan. Both unloaded and drug‐loaded nanoparticles were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) and showed a spherical morphology with an average hydrodynamic diameter between 40 and 80 nm. Both nanoparticles were stable and easily degraded by lysozyme. MTX‐loaded nanoparticles led to a greater mortality of MDA‐MB‐231 relative to free drug due to the ability of the nanoparticles to accumulate preferentially in neoplastic cells. The developed drug release system retains the ability to kill MDA‐MB‐231 cells in vitro, improving the survival of NIH3T3 cells.     

Arachidin-1, a Prenylated Stilbenoid from Peanut,Induces Apoptosis in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is unresponsive to typical hormonal treatments, causing it to be one of the deadliest forms of breast cancer. Investigating alternative therapies to increase survival rates for this disease is essential. The goal of this study was to assess cytotoxicity and apoptosis mechanisms of prenylated stilbenoids in TNBC cells. The prenylated stilbenoids arachidin-1 (A-1) and arachidin-3 (A-3) are analogs of resveratrol (RES) produced in peanut upon biotic stress. The anticancer activity of A-1 and A-3 isolated from peanut hairy root cultures was determined in TNBC cell lines MDA-MB-231 and MDA-MB-436. After 24 h of treatment, A-1 exhibited higher cytotoxicity than A-3 and RES with approximately 11-fold and six-fold lower IC₅₀, respectively, in MDA-MB-231 cells, and nine-fold and eight-fold lower IC₅₀, respectively, in MDA-MB-436 cells. A-1 did not show significant cytotoxicity in the non-cancerous cell line MCF-10A. While A-1 blocked cell division in G2-M phases in the TNBC cells, it did not affect cell division in MCF-10A cells. Furthermore, A-1 induced caspase-dependent apoptosis through the intrinsic pathway by activating caspase-9 and PARP cleavage, and inhibiting survivin. In conclusion, A-1 merits further research as a potential lead molecule for the treatment of TNBC.     

Smart Lipid–Polysaccharide Nanoparticles for Targeted Delivery of Doxorubicin to Breast Cancer Cells

In this study, actively-targeted (CD44-receptors) and dual stimuli (pH/redox)-responsive lipid–polymer nanoparticles were proposed as a delivery vehicle of doxorubicin hydrochloride in triple negative breast cancer cell lines. A phosphatidylcholine lipid film was hydrated with a solution of oxidized hyaluronic acid and doxorubicin, chosen as model drug, followed by a crosslinking reaction with cystamine hydrochloride. The obtained spherical nanoparticles (mean diameter of 30 nm) were found to be efficiently internalized in cancer cells by a receptor-mediated endocytosis process, and to modulate the drug release depending on the pH and redox potential of the surrounding medium. In vitro cytotoxicity assays demonstrated the safety and efficacy of the nanoparticles in enhancing the cytotoxic effect of the free anticancer drug, with the IC₅₀ values being reduced by two and three times in MDA-MB-468 and MDA-MB-231, respectively. The combination of self-assembled phospholipid molecules with a polysaccharide counterpart acting as receptor ligand, and stimuli-responsive chemical moieties, was carried out on smart multifunctional nanoparticles able to actively target breast cancer cells and improve the in vitro anticancer activity of doxorubicin.     

Tropinone-Derived Alkaloids as Potent Anticancer Agents: Synthesis,Tyrosinase Inhibition,Mechanism of Action,DFT Calculation,and Molecular Docking Studies

A new series of hybrid compounds with tropinone and thiazole rings in the structure was designed and synthesized as potential anticancer agents. They were tested against human multiple myeloma (RPMI 8226), lung carcinoma (A549), breast adenocarcinoma (MDA-MB-231), and mouse skin melanoma (B16-F10) cell lines. Toxicity was tested on human normal skin fibroblasts (HSF) and normal colon fibroblasts (CCD-18Co). The growth inhibition mechanism of the most active derivative was analyzed through investigation of its effect on the distribution of cell cycle phases and ability to induce apoptosis and necrosis in RPMI 8226 and A549 cancer cells. The tyrosinase inhibitory potential was assessed, followed by molecular docking studies. Compounds 3a–3h show high anticancer activity against MDA-MB-231 and B16-F10 cell lines with IC₅₀ values of 1.51–3.03 µM. Moreover, the cytotoxic activity of the investigated compounds against HSF and CCD-18Co cells was 8–70 times lower than against the cancer cells or no toxicity was shown in our tests, with derivative 3a being particularly successful. The mechanism of action of compound 3a in RPMI 8226 cell was shown to be through induction of cell death through apoptosis. The derivatives show ability to inhibit the tyrosinase activity with a mixed mechanism of inhibition. The final molecular docking results showed for IC₅₀ distinct correlation with experiment.     

Docosahexanoic Acid Improves Chemotherapy Efficacy by Inducing CD95 Translocation to Lipid Rafts in ER? Breast Cancer Cells

Docosahexanoic acid (DHA) and eicosapentanoic acid (EPA) have been shown to possess anti-carcinogenic properties in mammary cancers, both in vitro and in vivo. The objective of this study was to investigate the effect of treating three different breast cancer cell lines with DHA or EPA on cellular growth, chemotherapy efficacy, and CD95 expression and localization in the cell. MDA-MB-231, MCF-7 and SKBr-3 cells were incubated with EPA or DHA with or without chemotherapy agents [doxorubicin (dox), Herceptin]. Cell growth was assessed by WST-1 assay and CD95 expression was investigated using flow cytometry, Western blotting and confocal microscopy. DHA and EPA inhibited the growth of all three breast cancer cell lines in a dose-dependent fashion (P?<?0.05). DHA, and to a lesser extent EPA, induced the movement and raft clustering of CD95 in the cell membrane (via confocal microscopy) and the surface expression (via flow cytometry) in MDA-MB-231 cells. Neither fatty acid altered the growth/metabolic activity of the non-transformed MCF-12A breast cell line. Pre-treatment with DHA, but not EPA, improved the efficacy of dox in estrogen receptor negative MDA-MB-231 cells (P?<?0.05), but not in the other two cell lines. Pre-treating cells with DHA increased CD95 surface expression (threefold) and the plasma membrane raft content of CD95 (2fold) and FADD (>4-fold) after dox treatment, compared to dox treatment alone (P?<?0.05). This study demonstrated that pre-treatment of estrogen receptor negative MDA-MB-231 cells with DHA increased the anti-cancer effects of dox and presents evidence to suggest that this may be mediated in part by CD95-induced apoptosis.     

Sanguinarine Inhibition of TNF-α-Induced CCL2, IKBKE/NF-κB/ERK1/2 Signaling Pathway,and Cell Migration in Human Triple-Negative Breast Cancer Cells

Angiogenesis is a process that drives breast cancer (BC) progression and metastasis, which is linked to the altered inflammatory process, particularly in triple-negative breast cancer (TNBC). In targeting inflammatory angiogenesis, natural compounds are a promising option for managing BC. Thus, this study was designed to determine the natural alkaloid sanguinarine (SANG) potential for its antiangiogenic and antimetastatic properties in triple-negative breast cancer (TNBC) cells. The cytotoxic effect of SANG was examined in MDA-MB-231 and MDA-MB-468 cell models at a low molecular level. In this study, SANG remarkably inhibited the inflammatory mediator chemokine CCL2 in MDA-MB-231 and MDA-MB-468 cells. Furthermore, qRT-PCR confirmed with Western analysis studies showed that mRNA CCL2 repression was concurrent with reducing its main regulator IKBKE and NF-κB signaling pathway proteins in both TNBC cell lines. The total ERK1/2 protein was inhibited in the more responsive MDA-MB-231 cells. SANG exhibited a higher potential to inhibit cell migration in MDA-MB-231 cells compared to MDA-MB-468 cells. Data obtained in this study suggest a unique antiangiogenic and antimetastatic effect of SANG in the MDA-MB-231 cell model. These effects are related to the compound’s ability to inhibit the angiogenic CCL2 and impact the ERK1/2 pathway. Therefore, SANG use may be recommended as a component of the therapeutic strategy for TNBC.     

Interleukin-32θ Triggers Cellular Senescence and Reduces Sensitivity to Doxorubicin-Mediated Cytotoxicity in MDA-MB-231 Cells

The recently discovered interleukin (IL)- 32 isoform IL-32θ exerts anti-metastatic effects in the breast tumor microenvironment. However, the involvement of IL-32θ in breast cancer cell proliferation is not yet fully understood; therefore, the current study aimed to determine how IL-32θ affects cancer cell growth and evaluated the responses of IL-32θ-expressing cells to other cancer therapy. We compared the functions of IL-32θ in triple-negative breast cancer MDA-MB-231 cells that stably express IL-32θ, with MDA-MB-231 cells transfected with a mock vector. Slower growth was observed in cells expressing IL-32θ than in control cells, and changes were noted in nuclear morphology, mitotic division, and nucleolar size between the two groups of cells. Interleukin-32θ significantly reduced the colony-forming ability of MDA-MB-231 cells and induced permanent cell cycle arrest at the G1 phase. Long-term IL-32θ accumulation triggered permanent senescence and chromosomal instability in MDA-MB-231 cells. Genotoxic drug doxorubicin (DR) reduced the viability of MDA-MB-231 cells not expressing IL-32θ more than in cells expressing IL-32θ. Overall, these findings suggest that IL-32θ exerts antiproliferative effects in breast cancer cells and initiates senescence, which may cause DR resistance. Therefore, targeting IL-32θ in combination with DR treatment may not be suitable for treating metastatic breast cancer.     

Relationship of In Vitro Toxicity of Technetium-99m to Subcellular Localisation and Absorbed Dose

Auger electron-emitters increasingly attract attention as potential radionuclides for molecular radionuclide therapy in oncology. The radionuclide technetium-99m is widely used for imaging; however, its potential as a therapeutic radionuclide has not yet been fully assessed. We used MDA-MB-231 breast cancer cells engineered to express the human sodium iodide symporter-green fluorescent protein fusion reporter (hNIS-GFP; MDA-MB-231.hNIS-GFP) as a model for controlled cellular radionuclide uptake. Uptake, efflux, and subcellular location of the NIS radiotracer [^99mTc]TcO₄⁻ were characterised to calculate the nuclear-absorbed dose using Medical Internal Radiation Dose formalism. Radiotoxicity was determined using clonogenic and γ-H2AX assays. The daughter radionuclide technetium-99 or external beam irradiation therapy (EBRT) served as controls. [^99mTc]TcO₄⁻ in vivo biodistribution in MDA-MB-231.hNIS-GFP tumour-bearing mice was determined by imaging and complemented by ex vivo tissue radioactivity analysis. [^99mTc]TcO₄⁻ resulted in substantial DNA damage and reduction in the survival fraction (SF) following 24 h incubation in hNIS-expressing cells only. We found that 24,430 decays/cell (30 mBq/cell) were required to achieve SF_0.37 (95%-confidence interval = [SF_0.31; SF_0.43]). Different approaches for determining the subcellular localisation of [^99mTc]TcO₄⁻ led to SF_0.37 nuclear-absorbed doses ranging from 0.33 to 11.7 Gy. In comparison, EBRT of MDA-MB-231.hNIS-GFP cells resulted in an SF_0.37 of 2.59 Gy. In vivo retention of [^99mTc]TcO₄⁻ after 24 h remained high at 28.0% ± 4.5% of the administered activity/gram tissue in MDA-MB-231.hNIS-GFP tumours. [^99mTc]TcO₄⁻ caused DNA damage and reduced clonogenicity in this model, but only when the radioisotope was taken up into the cells. This data guides the safe use of technetium-99m during imaging and potential future therapeutic applications.     

Incorporation of Sulfonamide Moiety into Biguanide Scaffold Results in Apoptosis Induction and Cell Cycle Arrest in MCF-7 Breast Cancer Cells

Metformin, apart from its glucose-lowering properties, has also been found to demonstrate anti-cancer properties. Anti-cancer efficacy of metformin depends on its uptake in cancer cells, which is mediated by plasma membrane monoamine transporters (PMAT) and organic cation transporters (OCTs). This study presents an analysis of transporter mediated cellular uptake of ten sulfonamide-based derivatives of metformin in two breast cancer cell lines (MCF-7 and MDA-MB-231). Effects of these compounds on cancer cell growth inhibition were also determined. All examined sulfonamide-based analogues of metformin were characterized by greater cellular uptake in both MCF-7 and MDA-MB-231 cells, and stronger cytotoxic properties than those of metformin. Effective intracellular transport of the examined compounds in MCF-7 cells was accompanied by high cytotoxic activity. For instance, compound 2 with meta-methyl group in the benzene ring inhibited MCF-7 growth at micromolar range (IC₅₀ = 87.7 ± 1.18 µmol/L). Further studies showed that cytotoxicity of sulfonamide-based derivatives of metformin partially results from their ability to induce apoptosis in MCF-7 and MDA-MB-231 cells and arrest cell cycle in the G0/G1 phase. In addition, these compounds were found to inhibit cellular migration in wound healing assay. Importantly, the tested biguanides are more effective in MCF-7 cells at relatively lower concentrations than in MDA-MB-231 cells, which proves that the effectiveness of transporter-mediated accumulation in MCF-7 cells is related to biological effects, including MCF-7 cell growth inhibition, apoptosis induction and cell cycle arrest. In summary, this study supports the hypothesis that effective transporter-mediated cellular uptake of a chemical molecule determines its cytotoxic properties. These results warrant a further investigation of biguanides as putative anti-cancer agents.     

格尔德霉素对SMYD3核转位的影响

采用Western blot检测法研究了不同浓度的格尔德霉素对人乳腺癌细胞MDA-MB-231中SET和MYND结构域蛋白3(SMYD3)核转位的影响,采用MTT比色法检测了格尔德霉素对人乳腺癌细胞MDA-MB-231增殖的影响。结果表明:格尔德霉素可以抑制SMYD3的核转位,并且这种抑制作用是浓度依赖性的;与对照组相比,人乳腺癌细胞MDA-MB-231的增殖速率被显著地抑制了。说明格尔德霉素可以通过抑制SMYD3的核转位显著抑制人乳腺癌细胞MDA-MB-231的增殖。