Synthesis and Evaluation of High Functionality and Quality Cell-penetrating Peptide Conjugated Lipid for Octaarginine Modified PEGylated Liposomes In U251 and U87 Glioma Cells

The use of peptide ligand modified PEGylated liposomes has been widely investigated for tumor targeting. Peptides are mainly inserted in the liposomal lipid bilayer using PEG_2K-lipid spacer (Peptide-PEG_2K-DSPE). However, a lower cellular uptake from longer nonlinear PEG_2K spacer was reported, we here synthesized a high functionality and quality (HFQ) lipid with a short, linear serine-glycine repeated peptide [(SG)₅] spacer. The objective of the current study is to develop novel octaarginine (R₈) peptide-HFQ lipid grafted PEGylated liposomes for glioma cells targeting. In vitro liposomes characterization showed that the mean particle size of all liposomal formulations was in the nano-scale range < 120 nm, with a small PDI value (i.e. ～0.2) and had a spherical shape under Transmission Electron Microscope, indicating a homogenous particle size distribution. The flow cytometry in vitro cellular association data with U251 MG and U87 cells revealed that 1.5% R₈-(SG)₅-lipid-PEGylated liposomes exhibited significantly higher cellular association of ～15.87 and 7.59-fold than the conventional R₈-PEG_2K-lipid-PEGylated liposomes (10.4 and 6.19-fold), respectively, relative to the unmodified PEGylated liposomes. Moreover, intracellular distribution studies using confocal laser scanning microscopy (CLSM) corroborated the results of the in vitro cell association. The use of ligand-HFQ-lipid liposomes could be a potential alternative to ligand-PEG_2K-lipid-modified liposomes as a drug delivery system for tumor targeting.     

Amygdalin Regulates Apoptosis and Adhesion in Hs578T Triple-Negative Breast Cancer Cells

Amygdalin, D-mandelonitrile-β-D-glucoside-6-β-glucoside, belongs to aromatic cyanogenic glycoside group derived from rosaceous plant seed. Mounting evidence has supported the anti-cancer effects of amygdalin. However, whether amygdalin indeed acts as an anti-tumor agent against breast cancer cells is not clear. The present study aimed to investigate the effect of amygdalin on the proliferation of human breast cancer cells. Here, we show that amygdalin exerted cytotoxic activities on estrogen receptors (ER)-positive MCF7 cells, and MDA-MB-231 and Hs578T triple-negative breast cancer (TNBC) cells. Amygdalin induced apoptosis of Hs578T TNBC cells. Amygdalin downregulated B-cell lymphoma 2 (Bcl-2), upregulated Bcl-2-associated X protein (Bax), activated of caspase-3 and cleaved poly ADP-ribose polymerase (PARP). Amygdalin activated a pro-apoptotic signaling molecule p38 mitogen-activated protein kinases (p38 MAPK) in Hs578T cells. Treatment of amygdalin significantly inhibited the adhesion of Hs578T cells, in which integrin α5 may be involved. Taken together, this study demonstrates that amygdalin induces apoptosis and inhibits adhesion of breast cancer cells. The results suggest a potential application of amygdalin as a chemopreventive agent to prevent or alleviate progression of breast cancer, especially TNBC.     

Activity of Indatuximab Ravtansine against Triple-Negative Breast Cancer in Preclinical Tumor Models

Purpose

Triple-negative breast cancer (TNBC) is related with a poor prognosis as patients do hardly benefit from approved therapies. CD138 (Syndecan-1) is upregulated on human breast cancers. Indatuximab ravtansine (BT062) is an antibody-drug-conjugate that specifically targets CD138-expressing cells and has previously shown clinical activity in multiple myeloma. Here we show indatuximab ravtansine as a potential mono- and combination therapy for TNBC.

Methods

The effects of indatuximab ravtansine were assessed in vitro in SK-BR-3 and T47D breast cancer cell lines. The in vivo effects of indatuximab ravtansine alone and in combination with docetaxel or paclitaxel were assessed in MAXF401, MAXF1384 and MAXF1322 xenograft TNBC models.

Results

CD138⁺ SK-BR-3 and T47D cells were highly sensitive to indatuximab ravtansine. The high CD138-expressing MAXF401 xenograft model demonstrated strong inhibition of tumor growth with 4 mg/kg indatuximab ravtansine. High doses of indatuximab ravtansine (8 mg/kg), docetaxel and the combination of both led to complete remission. In the low CD138-expressing MAXF1384 xenograft model, only combination of indatuximab ravtansine and docetaxel demonstrated a significant efficacy. In the MAXF1322 xenograft model, indatuximab ravtansine alone and in combination with paclitaxel elicited complete remission.

Conclusions

These data demonstrate potential use of indatuximab ravtansine in combination with docetaxel or paclitaxel for CD138-positive TNBC.

     

Improved delivery of miR-1296 loaded cationic nanoliposomes for effective suppression of triple negative breast cancer

Nowadays, microRNA is considered an attractive strategy for the effective treatment of cancer. A significant delivery of microRNA for cancer therapy remains a significant obstacle to target cancer cells. The restoring microRNA-1296 (miR-1296) has immense therapeutic efficacy in triple-negative breast cancer (TNBC). TNBC is an aggressive subtype of breast tumors with the progression of malignant transformation. This study aimed to develop a cationic nanoliposome that can serve as a miR-1296 carrier and studied its efficiency in TNBC. The efficacy of miR-1296 liposomes was evaluated on its apoptotic effect, cellular uptake, and potential chemotherapy sensitization in the TNBC cell line (MDA-MB-231). For in vitro viability study, the apoptotic effect was performed to validate protein expression using Alamar blue kit and western blot. The transfection of miR-1296 into TNBC cells was also investigated using cisplatin as a TNBC resistance drug. The fluorescent miR-1296-cy3 liposome was used for cellular uptake study. The miR-liposome was successfully prepared with a particle size of 123.6 ± 1.3 nm and encapsulation efficiency of 94.33%. A dose of 0.5 uM has significantly reduced the viability of MDA-MB-231 to be 33.45%±5.29 (P < 0.001). This result was validated by down-expression of CCND1, and PARP1, the miR-1296 receptor, and apoptosis marker. The image of the miR-1296-cy3 liposome showed cytoplasmic intracellular localization. It was found high sensitization of TNBC cell line for miR-1296 liposome compared to cisplatin (P < 0.001). Future in vivo research may answer questions concerning safety and stability. This study demonstrates that miR-191 liposomes may have promising clinical applications for TNBC therapy.     

Monoacylglycerol Lipase Inhibitor JJKK048 Ameliorates ABCG2 Transporter-Mediated Regorafenib Resistance Induced by Hypoxia in Triple Negative Breast Cancer Cells

Triple negative breast cancer (TNBC) is among the most aggressive and deadly cancer subtypes. Intra-tumoral hypoxia is associated with aggressiveness and drug resistance in TNBC. One of the underlying mechanisms of hypoxia-induced drug resistance is the elevated expression of efflux transporters such as breast cancer resistant protein (ABCG2). In the present study, we investigated the possibility of ameliorating ABCG2-mediated drug resistance in hypoxic TNBC cells by monoacylglycerol lipase (MAGL) inhibition and the consequent downregulation of ABCG2 expression.The effect of MAGL inhibition on ABCG2 expression, function, and efficacy of regorafenib, an ABCG2 substrate was investigated in cobalt dichloride (CoCl₂) induced pseudohypoxic TNBC (MDA-MB-231) cells, using quantitative targeted absolute proteomics, qRT-PCR, anti-cancer drug accumulation in the cells, cell invasiveness and resazurin-based cell viability assays.Our results showed that hypoxia-induced ABCG2 expression led to low regorafenib intracellular concentrations, reduced the anti-invasiveness efficacy, and elevated half maximal inhibitory concentration (IC₅₀) of regorafenib in vitro MDA-MB-231 cells. MAGL inhibitor, JJKK048, reduced ABCG2 expression, increased regorafenib cell accumulation, which led to higher regorafenib efficacy.In conclusion, hypoxia-induced regorafenib resistance due to ABCG2 over-expression in TNBC cells can be ameliorated by MAGL inhibition.     

pH-Sensitive PEGylated liposomes functionalized with a fibronectin-mimetic peptide show enhanced intracellular delivery to colon cancer cell

pH-sensitive liposomes undergo rapid destabilization under mildly acidic conditions such as those found in endocytotic vesicles. Though this makes them promising drug carriers, their application is limited due to their rapid clearance from circulation by the reticulo-endothelial system. Researchers have therefore used pH-sensitive liposomes that are sterically stabilized by polyethylene glycol (PEG) molecules (stealth liposomes) on the liposome surface. The goal of this study is to bring bio-functionality to pH-sensitive PEGylated liposomes in order to facilitate their potential use as a targeted drug delivery agent. To improve the selectivity of these nanoparticles, we included a targeting moiety, PR_b which specifically recognizes and binds to integrin α(5)β(1) expressing cells. PR_b (KSSPHSRN(SG)(5)RGDSP) is a novel fibronectin-mimetic peptide sequence that mimics the cell adhesion domain of fibronectin. Integrin α(5)β(1) is expressed on several types of cancer cells, including colon cancer, and plays an important role in tumor growth and metastasis. We have thoroughly studied the release of calcein from pH-sensitive PEGylated liposomes by varying the lipid composition of the liposomes in the absence and presence of the targeting peptide, PR_b, and accounting for the first time for the effect of both pH and time (photo-bleaching effect) on the fluorescence signal of calcein. We have demonstrated that we can design PR_b-targeted pH-sensitive PEGylated liposomes, which can undergo destabilization under mildly acidic conditions and have shown that incorporating the PR_b peptide does not significantly affect the pH-sensitivity of the liposomes. PR_b-targeted pH-sensitive PEGylated liposomes bind to CT26.WT colon carcinoma cells that express integrin α(5)β(1), undergo cellular internalization, and release their load intracellularly in a short period of time as compared to other formulations. Our studies demonstrate that PR_b-functionalized pH-sensitive targeted delivery systems have the potential to deliver a payload directly to cancer cells in an efficient and specific manner.     

Antiproliferation and apoptosis studies of estrone pharmacophores in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that shows high metastatic capability and poor prognosis. The aggressive behavior of TNBC may involve amplified EGFR expression. Currently, no targeted therapy has been approved for treating TNBC, which urgently needs novel treatment options. In this study, we report that estrone analogs with novel pharmacophores exhibited high potency toward TNBC cells through multiple mechanisms, inhibition of cell proliferation via EGFR receptor, and induction of mitochondrial apoptosis. Molecular docking studies revealed that hit analogs MMA307 and MMA321 were potent against the EGFR receptor (pdb code: 1M17) in silico and were over 10-fold more potent than sorafenib (positive control) when dosed against MDA-MB-468 cells in vitro. MMA307 and MMA321 induced mitochondrial apoptosis as characterized by condensed nuclei with fragmented chromatin, phosphatidylserine flip and modulated expressions of Apaf1, cytochrome c, and caspases 3 and 9. MMA307 and MMA321 inhibited TNBC proliferation through suppression of EGFR and activated EGFR (Y1068) expressions. Similarly, EGFR signaling pathways, RAF/ERK and AKT/mTOR, were inhibited as pARaf, pERK1/2 (characterizes RAF/ERK pathway) and pAKT, pmTOR, p70S6Kα (characterizes AKT/mTOR pathway) were all suppressed. Moreover, MMA307 and MMA321 inhibited TNBC cell growth through downregulation of cyclin D1 expression and arresting TNBC cells in the G₁ phase of cell cycle. This study reports for the first time that estrone congeners with novel pharmacophores may be an effective therapy for TNBC. Findings from this research provide a solid foundation for further preclinical and clinical studies in developing estrone derivatives as novel TNBC therapeutics.     

Magnetically Guided Self-Assembled Protein Micelles for Enhanced Delivery of Dasatinib to Human Triple-Negative Breast Cancer Cells

Magnetic nanocarriers are useful in targeted cancer therapy. Dasatinib (DAS)-loaded magnetic micelles were prepared for magnetically guided drug delivery. The magnetic nanoplatform is composed of hydrophobic oleic acid–coated magnetite (Fe₃O₄) core along with DAS encapsulated in amphiphilic zein-lactoferrin self-assembled polymeric micelles. Transmission electron microscope analysis manifested formation of these magnetic micelles with a mean diameter of about 100 nm. In addition, drug-loaded magnetic micelles displayed a saturation magnetization of about 10.01 emu.g^?1 with a superparamagnetic property. They also showed good in vitro serum stability and hemocompatibility accompanied with a sustained release of DAS in acidic pH. More importantly, they exhibited 1.35-fold increase in their in vitro cytotoxicity against triple-negative human breast cancer cell line (MDA-MB-231) using an external magnetic field compared to drug-loaded magnetic micelles in the absence of a magnetic field. Enhanced inhibition of p-c-Src protein expression level and in vitro cellular migration under the effect of magnetic field was noted owing to the dual-targeting strategy offered by the presence of a magnetic sensitive core, as well as the active targeting property of lactoferrin corona. Taken all together, these results suggest that DAS-loaded magnetic micelles possess a great potential for targeted therapy of breast cancer.     

PHSCNK-Modified and doxorubicin-loaded liposomes as a dual targeting system to integrin-overexpressing tumor neovasculature and tumor cells

The aim of this study was to prepare a liposome system targeting to both tumor angiogenesis and tumor cells, and to achieve the proof-of-principle. ATN-161 (N-acetyl-proline-histidine-serine-cysteine-asparagine-amide, PHSCN) is a ligand of integrin α5β1 which is the receptor overexpressed on tumor neovasculature and some tumor cells. In this study, doxorubicin (DOX) was used as the model drug, and a derivative of PHSCN, N-acetyl-proline-histidine-serine-cysteine-asparagine-lysine (amide)-COOH (PHSCNK), was firstly coupled to the surface of PEGylated DOX liposomes (PL-DOX) by a novel approach to obtain the PHSCNK-modified and DOX-loaded PEGylated liposomes (PHSCNK-PL-DOX). These two vehicles were less than 100?nm in average, negatively charged and rather stable at 4°C or 25°C, while they exhibited similar release kinetics in vitro. Cell-specific uptake and cytotoxicity were investigated on human umbilical vein endothelial cells and breast cancer cells by confocal microscopy and sulforhodamine B (SRB) assay. It was found that PHSCNK-PL-DOX significantly enhanced the cell uptake and cytotoxicity of DOX on both cell lines, due to the integrin-mediated endocytosis. It was concluded that, PHSCNK-PL-DOX, which can actively delivery the drug into both tumor neovasculature and tumor cells, may be a promising targeted delivery system for anticancer drug.     

Bioinformatics Prediction and In Vitro Analysis Revealed That miR‐17 Targets Cyclin D1 mRNA in Triple Negative Breast Cancer Cells

Breast cancer is one of the most prevalent malignancies among women worldwide. Triple negative breast cancer (TNBC) is a type of breast cancer in which estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER‐2) are not expressed. There is no targeted therapy for this type of cancer, and available therapies have poor therapeutic effects. Performing a preliminary research, we selected cyclin D1 (CCND1) gene of Wnt signaling pathway which is a target of miRNAs, a promising set of biomolecules in diagnosis and treatment of breast cancer. In this study using bioinformatic analyses, miR‐17 was selected as it targets the 3′UTR of CCND1 gene with the highest score. Luciferase assay results also confirmed the bioinformatic prediction. Decreased expression of miR‐17 in MDA‐MB‐231 cell line was observed using qRT‐PCR method. After lentiviral transduction of miR‐17 to the target cells, gene expression analysis showed decreased expression of CCND1 gene. We found miR‐17 as an attractive molecule that after intensive research can probably be used as a biomarker in TNBC.     

BML-111 inhibits EMT,migration and metastasis of TAMs-stimulated triple-negative breast cancer cells via ILK pathway

Triple-negative breast cancer (TNBC) has a more aggressive phenotype and higher metastasis and recurrence rates than other breast cancer subtypes. The immune microenvironment and hypoxic microenvironment of breast cancer constitute the survival environment of cancer cells, which is an important environment to support cancer cells. LXA₄ and its analog, BML-111 is an important regulator of inflammatory cytokines, which provides a possible way for the treatment of inflammatory-related tumors. Here, in the in vitro experiment, we showed that BML-111 could inhibit the EMT and migration of TAMs-stimulated TNBC by down-regulating ILK as well as p-Akt and p-GSK3β. And it could prevent the formation of breast cancer cell clusters. In the in vivo experiment, BML-111 could inhibit the metastasis of 4T1 breast cancer cells. We also demonstrated that BML-111 could affect macrophages in tumor microenvironment to prevent metastasis. These results showed that BML-111 could be a possible candidate for breast cancer therapy by targeting ILK and TAMs.     

Development of High-Content Gemcitabine PEGylated Liposomes and Their Cytotoxicity on Drug-Resistant Pancreatic Tumour Cells

Purpose

The objective of this study was to develop high-content gemcitabine PEGylated liposomes to reverse gemcitabine resistance in pancreatic tumour cells. The mechanism of drug loading into liposomes was also investigated.

Methods

To increase the drug entrapment efficiency (EE) and drug loading (DL), a novel passive loading approach named Small Volume Incubation method (SVI) was developed and compared to the reverse phase evaporation (REV) and remote loading methods. The in vitro cytotoxicity was evaluated using MIA PaCa-2 and Panc-1 cell lines.

Results

The EE for remote loading was 12.3?±?0.3%, much lower than expected and a burst release was observed with the resultant liposomes. Using the optimized SVI method, increased EE (37?±?1%) and DL (4%, w/w) were obtained. The liposomes (200?±?5 nm) showed minimal drug leakage, good stability, and significant improvement in cytotoxicity to the gemcitabine-resistant pancreatic cancer cell lines.

Conclusions

Remote loading was not suitable for loading gemcitabine into liposomes. pK_a?>?4.6 for basic drugs and intra-liposomal precipitation of loaded compounds were suggested as an additional requirement to the current criteria for remote loading using ammonium sulphate gradient (pK_a?相似文献   

Anti-Cancer Effect of IN-2001 in MDA-MB-231 Human Breast Cancer

In recent years, inhibition of HDACs has emerged as a potential strategy to reverse aberrant epigenetic changes associated with cancer, and several classes of HDAC inhibitors have been found to have potent and specific anticancer activities in preclinical studies. But their precise mechanism of action has not been elucidated. In this study, a novel synthetic inhibitor of HDAC, 3-(4-dimethylamino phenyl)-N-hydroxy-2-propenamide [IN-2001] was examined for its antitumor activity and the underlying molecular mechanisms of any such activity on human breast cancer cell lines. IN-2001 effectively inhibited cellular HDAC activity (IC₅₀ = 0.585 nM) in MDA-MB-231 human breast cancer cells. IN-2001 caused a significant dose-dependent inhibition of cell proliferation in estrogen receptor (ER) negative MDA-MB-231 human breast cancer cells. Cell cycle analysis revealed that the gowth inhibitory effects of IN-2001 might be attributed to cell cycle arrest at G₀/G₁ and/or G₂/Mphase and subsequent apoptosis in human breast cancer cells. These events are accompanied by modulating several cell cycle and apoptosis regulatory genes such as CDK inhibitors p21^WAF1 and p27^KIP1 cyclin D1, and other tumor suppressor genes such as cyclin D2. Collectively, IN-2001 inhibited cell proliferation and induced apoptosis in human breast cancer cells and these findings may provide new therapeutic approaches, combination of antiestrogen together with a HDAC inhibitor, in the hormonal therapy-resistant ER-negative breast cancers. In summary, our data suggest that this histone deacetylase inhibitor, IN-2001, is a novel promising therapeutic agent with potent antitumor effects against human breast cancers.     

Antitumor Effect of Paclitaxel-Loaded PEGylated Immunoliposomes Against Human Breast Cancer Cells

Purpose The antitumor effect of paclitaxel-loaded PEGylated immunoliposome (PILs) was investigated in breast cancer cell lines and the xenograft model. Methods Herceptin was conjugated to paclitaxel-loaded PEGylated liposomes (PLs). In vitro cellular uptake and cytotoxicity of PILs were determined in breast cancer cell lines while in vivo antitumor efficacy was evaluated in the xenograft nude mouse model. Results The PILs formulation was able to significantly increase the HER2 mediated cellular uptake of paclitaxel compared to the PLs in cell lines overexpressing HER2 (BT-474 and SK-BR-3 cells). However, in the MDA-MB-231 cells, which express low levels of HER2, the difference between the PILs and PLs formulation was not significant. The biological activity of Herceptin was maintained throughout the conjugation process as exhibited by the antitumor dose–response curves determined for Herceptin itself, for the thiolated Herceptin alone and subsequently for the immunoliposome-coupled Herceptin. In BT-474 and SK-BR-3 cells, the cytotoxicity of the PILs was more potent than that of Taxol. Moreover, in in vivo studies, PILs showed significantly higher tumor tissue distribution of paclitaxel in the BT-474 xenograft model and more superior antitumor efficacy compared to Taxol and PLs. However, in the MDA-MB-231 xenograft model, PILs and PLs showed similar tumor tissue distribution as well as antitumor activity. Conclusions These results suggest that HER2-mediated endocytosis is involved in the PILs formulation. The ability of the PILs formulation to efficiently and specifically deliver paclitaxel to the HER2-overexpressing cancer cells implies that it is a promising strategy for tumor-specific therapy for HER2-overexpressing breast cancers.     

Curcumin: a calixarene derivative micelle potentiates anti-breast cancer stem cells effects in xenografted,triple-negative breast cancer mouse models

Triple-negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease with no approved targeted therapy. Curcumin has shown therapeutic potential against TNBC, but it shows low bioavailability and low efficacy when administered as a free drug. Here we describe a novel vehicle for in vivo delivery of curcumin based on the phosphorylated calixarene POCA4C6. Curcumin-loaded POCA4C6 micelles (CPM) were prepared using the thin-film method and they showed a unilamellar structure with an average particle size of 3.86?nm. The micelles showed high curcumin encapsulation efficiency and loading was based on liquid chromatography-tandem mass spectrometry. Studies with cell cultures suggest that CPM can sustainably release curcumin in a pH-dependent manner. The micelles efficiently inhibited proliferation, invasion, migration and tumor spheroid formation by BT-549 human breast cancer cells. These effects involved increased apoptosis and reduced levels of nuclear β-catenin and androgen receptor. After injection into tumor xenografts, CPM persisted in the tumor tissue and efficiently inhibited tumor growth without causing obvious systemic toxicity. CPM also significantly reduced levels of CD44⁺/CD133⁺ breast cancer stem cells. Our results highlight the potential of CPM as an effective therapy against TNBC.     

Isotoosendanin exerts inhibition on triple-negative breast cancer through abrogating TGF-β-induced epithelial–mesenchymal transition via directly targeting TGFβR1

As the most aggressive breast cancer, triple-negative breast cancer (TNBC) is still incurable and very prone to metastasis. The transform growth factor β (TGF-β)-induced epithelial–mesenchymal transition (EMT) is crucially involved in the growth and metastasis of TNBC. This study reported that a natural compound isotoosendanin (ITSN) reduced TNBC metastasis by inhibiting TGF-β-induced EMT and the formation of invadopodia. ITSN can directly interact with TGF-β receptor type-1 (TGFβR1) and abrogated the kinase activity of TGFβR1, thereby blocking the TGF-β-initiated downstream signaling pathway. Moreover, the ITSN-provided inhibition on metastasis obviously disappeared in TGFβR1-overexpressed TNBC cells in vitro as well as in mice bearing TNBC cells overexpressed TGFβR1. Furthermore, Lys232 and Asp351 residues in the kinase domain of TGFβR1 were found to be crucial for the interaction of ITSN with TGFβR1. Additionally, ITSN also improved the inhibitory efficacy of programmed cell death 1 ligand 1 (PD-L1) antibody for TNBC in vivo via inhibiting the TGF-β-mediated EMT in the tumor microenvironment. Our findings not only highlight the key role of TGFβR1 in TNBC metastasis, but also provide a leading compound targeting TGFβR1 for the treatment of TNBC metastasis. Moreover, this study also points out a potential strategy for TNBC treatment by using the combined application of anti-PD-L1 with a TGFβR1 inhibitor.     

Preclinical Evaluation of Ixabepilone in Combination with VEGF Receptor and PARP Inhibitors in Taxane-Sensitive and Taxane-Resistant MDA-MB-231 Breast Cancer Cells

Long-term use of cytotoxic agents promotes drug-resistance in triple-negative breast cancer (TNBC). The identification of new drug combinations with efficacy against drug-resistant TNBC cells in vitro is valuable in developing new clinical strategies to produce further cancer remissions. We undertook combination analysis of the cytotoxic agent ixabepilone with small molecule inhibitors of vascular endothelial growth factor receptor (VEGFR) and poly (ADP-ribose) polymerase (PARP) in taxane-sensitive (231C) and taxane-resistant (TXT) MDA-MB-231-derived cells. As single agents, the VEGFR inhibitors cediranib and bosutinib decreased both 231C and TXT cell viability, but four other VEGFR inhibitors and two PARP inhibitors were less effective. Combinations of ixabepilone with either cediranib or bosutinib synergistically decreased 231C cell viability. However, only the ixabepilone/cediranib combination was synergistic in TXT cells, with predicted 15.3-fold and 1.65-fold clinical dose reductions for ixabepilone and cediranib, respectively. Flow cytometry and immunoblotting were used to further evaluate the loss of cell viability. Thus, TXT cell killing by ixabepilone/cediranib was enhanced over ixabepilone alone, and expression of proapoptotic cleaved caspase-3 and the Bak/Bcl-2 protein ratio were increased. These findings suggest that the synergistic activity of the ixabepilone/cediranib combination in taxane-sensitive and taxane-resistant cells may warrant clinical evaluation in TNBC patients.     

Peptide PHSCNK as an integrin α5β1 antagonist targets stealth liposomes to integrin-overexpressing melanoma

As an integrin α₅β₁ antagonist, N-acetyl-proline-histidine-serine-cysteine-asparagine-amide (Ac-PHSCN-NH₂) is currently in phase II trials for various cancer therapies. In this study Ac-PHSCNK-NH₂ (PHSCNK) was used as a novel homing peptide to prepare ligand-targeted liposomes loaded with doxorubicin (PHSCNK-PL-DOX), with the hypothesis that the therapy target of integrin α₅β₁ may also serve as a delivery target. The stealth liposomes loaded with doxorubicin (PL-DOX) were used as the control. PHSCNK-PL-DOX demonstrated an enhanced intracellular uptake and a greater cytotoxicity against melanoma B16F10 cells in comparison with PL-DOX. The novel targeted formulation displayed stronger tumor inhibition and prolonged survival time in comparison with controls in C57BL/6 mice bearing B16F10 tumors, and it exhibited less heart toxicity in hematoxylin-eosin (H&E) staining of tissues. Taking the pharmacokinetics and biodistribution results into account, the authors conclude that α₅β₁ integrin-mediated liposomes might be used as a potential delivery system for targeted tumor therapy.From the Clinical EditorLactosyl-norcantharidin TMC nanoparticles were found superior in comparison with Lac-NCTD and Lac-NCTD chitosan nanoparticles from the standpoint of antitumor activity on murine hepatocarcinoma 22 subcutaneous model.     

Curcumin-induced antitumor effects on triple-negative breast cancer patient-derived xenograft tumor mice through inhibiting salt-induced kinase-3 protein

This study demonstrated for the first time that curcumin effectively inhibits the growth of triple-negative breast cancer (TNBC) tumors by inhibiting the expression of salt-induced kinase-3 (SIK3) protein in patient-derived xenografted tumor mice (TNBC-PDX). For TNBC patients, chemotherapy is the only option for postoperative adjuvant treatment. In this study, we detected the SIK3 mRNA expression in paired-breast cancer tissues by qPCR analysis. The results revealed that SIK3 mRNA expression was significantly higher in tumor tissues when compared to the normal adjacent tissues (73.25 times, n = 183). Thus, it is proposed for the first time that the antitumor effect induced by curcumin by targeting SIK3 can be used as a novel strategy for the therapy of TNBC tumors. In vitro mechanism studies have shown that curcumin (>25 μM) inhibits the SIK3-mediated cyclin D upregulation, thereby inhibiting the G1/S cell cycle and arresting TNBC (MDA-MB-231) cancer cell growth. The SIK3 overexpression was associated with increased mesenchymal markers (i.e., Vimentin, α-SMA, MMP3, and Twist) during epithelial–mesenchymal transition (EMT). Our results demonstrated that curcumin inhibits the SIK3-mediated EMT, effectively attenuating the tumor migration. For clinical indications, dietary nutrients (such as curcumin) as an adjuvant to chemotherapy should be helpful to TNBC patients because the current trend is to shrink the tumor with preoperative chemotherapy and then perform surgery. In addition, from the perspective of chemoprevention, curcumin has excellent clinical application value.     

Highly expressed SERCA2 triggers tumor cell autophagy and is a druggable vulnerability in triple-negative breast cancer

Chemoresistance remains a major obstacle to successful treatment of triple negative breast cancer (TNBC). Identification of druggable vulnerabilities is an important aim for TNBC therapy. Here, we report that SERCA2 expression correlates with TNBC progression in human patients, which promotes TNBC cell proliferation, migration and chemoresistance. Mechanistically, SERCA2 interacts with LC3B via LIR motif, facilitating WIPI2-independent autophagosome formation to induce autophagy. Autophagy-mediated SERCA2 degradation induces SERCA2 transactivation through a Ca²⁺/CaMKK/CREB-1 feedback. Moreover, we found that SERCA2-targeting small molecule RL71 enhances SERCA2–LC3B interaction and induces excessive autophagic cell death. The increase in SERCA2 expression predisposes TNBC cells to RL71-induced autophagic cell death in vitro and in vivo. This study elucidates a mechanism by which TNBC cells maintain their high autophagy activity to induce chemoresistance, and suggests increased SERCA2 expression as a druggable vulnerability for TNBC.