In vivo deposition of poorly soluble drugs.

Administered drug molecules, whether dissolved or solubilized, have the potential to precipitate and accumulate as solid forms in tissues and cells within the body. This phase transition can significantly impact the pharmacokinetics of treatment. It is thus crucial to gain an understanding of how drug solubility/permeability, drug formulations and routes of administration affect in vivo behaviors of drug deposition. This review examines literature reports on the drug deposition in tissues and cells of poorly water-soluble drugs, as well as underlying physical mechanisms that lead to precipitation. Our work particularly highlights drug deposition in macrophages and the subcellular fate of precipitated drugs. We also propose a tissue permeability-based classification framework to evaluate precipitation potentials of poorly soluble drugs in major organs and tissues. The impact on pharmacokinetics is further discussed and needs to be considered in developing drug delivery systems. Finally, bioimaging techniques that are used to examine aggregated states and the intracellular trafficking of absorbed drugs are summarized.

Integration of caveolin-mediated cytosolic delivery and enzyme-responsive releasing of squalenoyl nanoparticles enhance the anti-cancer efficacy of chidamide in pancreatic cancer.

We explored the potential of overcoming the dense interstitial barrier in pancreatic cancer treatment by enhancing the uptake of hydrophilic chemotherapeutic drugs. In this study, we synthesized the squalenoyl-chidamide prodrug (SQ-CHI), linking lipophilic squalene (SQ) with the hydrophilic antitumor drug chidamide (CHI) through a trypsin-responsive bond. Self-assembled nanoparticles with sigma receptor-bound aminoethyl anisamide (AEAA) modification, forming AEAA-PEG-SQ-CHI NPs (A-C NPs, size 116.6 ± 0.4 nm), and reference nanoparticles without AEAA modification, forming mPEG-SQ-CHI NPs (M-C NPs, size 88.3 ± 0.3 nm), were prepared. A-C NPs exhibited significantly higher in vitro CHI release (74.7 %) in 0.5 % trypsin medium compared to release (20.2 %) in medium without trypsin. In vitro cell uptake assays revealed 3.6 and 2.3times higher permeation of A-C NPs into tumorspheres of PSN-1/HPSC or CFPAC-1/HPSC, respectively, compared to M-C NPs. Following intraperitoneal administration to subcutaneous tumor-bearing nude mice, the A-C NPs group demonstrated significant anti-pancreatic cancer efficacy, inducing cancer cell apoptosis and inhibiting proliferation in vivo. Mechanistic studies revealed that AEAA surface modification on nanoparticles promoted intracellular uptake through caveolin-mediated endocytosis. This nanoparticle system presents a novel therapeutic approach for pancreatic cancer treatment, offering a delivery strategy to enhance efficacy through improved tumor permeation, trypsin-responsive drug release, and specific cell surface receptor-mediated intracellular uptake.

Albumin conjugation promotes arsenic trioxide transport through alkaline phosphatase-associated transcytosis in MUC4 wildtype pancreatic cancer cells.

Pancreatic cancer (PC) has a poor prognosis due to chemotherapy resistance and unfavorable drug transportation. Albumin conjugates are commonly used as drug carriers to overcome these obstacles. However, membrane-bound glycoprotein mucin 4 (MUC4) has emerged as a promising biomarker among the genetic mutations affecting albumin conjugates therapeutic window. Human serum albumin-conjugated arsenic trioxide (HSA-ATO) has shown potential in treating solid tumors but is limited in PC therapy due to unclear targets and mechanisms. This study investigated the transport mechanisms and therapeutic efficacy of HSA-ATO in PC cells with different MUC4 mutation statuses. Results revealed improved penetration of ATO into PC tumors through conjugated with HSA. However, MUC4 mutation significantly affected treatment sensitivity and HSA-ATO uptake both in vitro and in vivo. Mutant MUC4 cells exhibited over ten times higher IC50 for HSA-ATO and approximately half the uptake compared to wildtype cells. Further research demonstrated that ALPL activation by HSA-ATO enhanced transcytosis in wildtype MUC4 PC cells but not in mutant MUC4 cells, leading to impaired uptake and weaker antitumor effects. Reprogramming the transport process holds potential for enhancing albumin conjugate efficacy in PC patients with different MUC4 mutation statuses, paving the way for stratified treatment using these delivery vehicles.

Preliminary delivery efficiency prediction of nanotherapeutics into crucial cell populations in bone marrow niche.

Several crucial stromal cell populations regulate hematopoiesis and malignant diseases in bone marrow niches. Precise regulation of these cell types can remodel niches and develop new therapeutics. Multiple nanocarriers have been developed to transport drugs into the bone marrow selectively. However, the delivery efficiency of these nanotherapeutics into crucial niche cells is still unknown, and there is no method available for predicting delivery efficiency in these cell types. Here, we constructed a three-dimensional bone marrow niche composed of three crucial cell populations: endothelial cells (ECs), mesenchymal stromal cells (MSCs), and osteoblasts (OBs). Mimetic niches were used to detect the cellular uptake of three typical drug nanocarriers into ECs/MSCs/OBs in vitro. Less than 5% of nanocarriers were taken up by three stromal cell types, and most of them were located in the extracellular matrix. Delivery efficiency in sinusoidal ECs, arteriole ECs, MSCs, and OBs in vivo was analyzed. The correlation analysis showed that the cellular uptake of three nanocarriers in crucial cell types in vitro is positively linear correlated with its delivery efficiency in vivo. The delivery efficiency into MSCs was remarkably higher than that into ECs and OBs, no matter what kind of nanocarrier. The overall efficiency into sinusoidal ECs was greatly lower than that into arteriole ECs. All nanocarriers were hard to be delivered into OBs (<1%). Our findings revealed that cell tropisms of nanocarriers with different compositions and ligand attachments in vivo could be predicted via detecting their cellular uptake in bone marrow niches in vitro. This study provided the methodology for niche-directed nanotherapeutics development.

Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy.

Cancer-associated fibroblasts (CAFs) are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment, leading to the failure of triple-negative breast cancer (TNBC) immunotherapy. Therefore, depleting CAFs may enhance the effect of immunotherapy (such as PD-L1 antibody). Relaxin (RLN) has been demonstrated to significantly improve transforming growth factor-ß (TGF-ß) induced CAFs activation and tumor immunosuppressive microenvironment. However, the short half-life and systemic vasodilation of RLN limit its in vivo efficacy. Here, plasmid encoding relaxin (pRLN) to locally express RLN was delivered with a new positively charged polymer named polymeric metformin (PolyMet), which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before. In order to improve the stability of pRLN in vivo, this complex was further formed lipid poly-γ-glutamic acid (PGA)/PolyMet-pRLN nanoparticle (LPPR). The particle size of LPPR was 205.5 ± 2.9 nm, and the zeta potential was +55.4 ± 1.6 mV. LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1luc/CAFs tumor spheres in vitro. In vivo, it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment, which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration. Thus, LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse, and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody (aPD-L1). Altogether, this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.

Reversing multi-drug resistance by polymeric metformin to enhance antitumor efficacy of chemotherapy.

Multi-drug resistance (MDR) in breast cancer poses a great threat to chemotherapy. The expression and function of the ATP binding cassette (ABC) transporter are the major cause of MDR. Herein, a linear polyethylene glycol (PEI) conjugated with dicyandiamide, which called polymeric metformin (PolyMet), was successfully synthesized as a simple and biocompatible polymer of metformin. PolyMet showed the potential to reverse MDR by inhibiting the efflux of the substrate of ATP-binding cassette (ABC) transporter from DOX resistant MCF-7 cells (MCF-7/DOX). To test its MDR reversing effect, PolyMet was combined with DOX to treat mice carrying MCF-7/DOX xenografts. In order to decrease the toxicities of DOX and delivery PolyMet and DOX to tumor at the same time, PolyMet was complexed with poly-γ-glutamic acid-doxorubicin (PGA-DOX) electrostatically at the optimal ratio of 2:3, which were further coated with lipid membrane to form lipid/PolyMet-(PGA-DOX) nanoparticles (LPPD). The particle size of LPPD was 165.8 nm, and the zeta potential was +36.5 mV. LPPD exhibited favorable cytotoxicity and cellular uptake in MCF-7/DOX. Meanwhile, the bioluminescence imaging and immunohistochemical analysis indicated that LPPD effectively conquered DOX-associated MDR by blocking ABC transporters (ABCB1 and ABCC1) via PolyMet. Remarkably, LPPD significantly inhibited the tumor growth and lowered the systemic toxicity in a murine MCF-7/DOX tumor model. This is the first time to reveal that PolyMet can enhance the anti-tumor efficacy of DOX by dampening ABC transporters and activating the AMPK/mTOR pathway, which is a promising strategy for drug-resistant breast cancer therapy.

The osteogenic niche-targeted arsenic nanoparticles prevent colonization of disseminated breast tumor cells in the bone.

Up to 70% of patients with late-stage breast cancer have bone metastasis. Current treatment regimens for breast cancer bone metastasis are palliative with no therapeutic cure. Disseminated tumor cells (DTCs) colonize inside the osteogenic niches in the early stage of bone metastasis. Drug delivery into osteogenic niches to inhibit DTC colonization can prevent bone metastasis from entering its late stage and therefore cure bone metastasis. Here, we constructed a 50% DSS6 peptide conjugated nanoparticle to target the osteogenic niche. The osteogenic niche was always located at the endosteum with immature hydroxyapatite. Arsenic-manganese nanocrystals (around 14 nm) were loaded in osteogenic niche-targeted PEG-PLGA nanoparticles with an acidic environment-triggered arsenic release. Arsenic formulations greatly reduced 4T1 cell adhesion to mesenchymal stem cells (MSCs)/preosteoblasts (pre-OBs) and osteogenic differentiation of osteoblastic cells. Arsenic formulations also prevented tumor cell colonization and dormancy via altering the direct interaction between 4T1 cells and MSCs/pre-OBs. The chemotactic migration of 4T1 cells toward osteogenic cells was blocked by arsenic in mimic 3D osteogenic niche. Systemic administration of osteogenic niche-targeted arsenic nanoparticles significantly extended the survival of mice with 4T1 syngeneic bone metastasis. Our findings provide an effective approach for osteogenic niche-specific drug delivery and suggest that bone metastasis can be effectively inhibited by blockage of tumor cell colonization in the bone microenvironment.

Cell-based therapeutics for the treatment of hematologic diseases inside the bone marrow.

Cell-based therapies could overcome the limitations of traditional drugs for the treatment of refractory diseases. Cell exchange between the bone marrow and blood is bidirectional. Several kinds of cells in the blood have the capability to enter the bone marrow by interacting with sinusoidal cells under specific physiological or pathological conditions. These cells are the potential living therapeutics or delivery vehicles to treat or prevent bone marrow-related hematologic diseases. In this review, we summarized the in vivo molecular mechanisms and kinetics of these cells in entering the bone marrow. The advances in the fabrication of living cell drugs and the strategies to design cell-based carriers into the bone marrow were discussed. The latest studies on how to use blood cells as living drugs or as drug carriers to improve therapeutic outcomes of hematologic diseases inside the bone marrow were highlighted.

Development of targeted therapy therapeutics to sensitize triple-negative breast cancer chemosensitivity utilizing bacteriophage phi29 derived packaging RNA.

BACKGROUND: To date, triple-negative breast cancer (TNBC) treatment options are limited because of the loss of target receptors and, as a result, are only managed with chemotherapy. What is worse is that TNBC is frequently developing resistance to chemotherapy. By using small interfering RNA (siRNA)-based therapeutics, our recent work demonstrated X-box-binding protein 1 (XBP1) was linked to human epidermal growth factor receptor 2 positive (HER2+) breast cancer development and chemoresistance. Given the instability, off-target effects, net negative charge, and hydrophobicity of siRNA in vivo utilization and clinical transformation, its use in treatment is hampered. Thus, the development of a siRNA-based drug delivery system (DDS) with ultra-stability and specificity is necessary to address the predicament of siRNA delivery. RESULTS: Here, we assembled RNase resistant RNA nanoparticles (NPs) based on the 3WJ structure from Phi29 DNA packaging motor. To improved targeted therapy and sensitize TNBC to chemotherapy, the RNA NPs were equipped with an epidermal growth factor receptor (EGFR) targeting aptamer and XBP1 siRNA. We found our RNA NPs could deplete XBP1 expression and suppress tumor growth after intravenous administration. Meanwhile, RNA NPs treatment could promote sensitization to chemotherapy and impede angiogenesis in vivo. CONCLUSIONS: The results further demonstrate that our RNA NPs could serve as an effective and promising platform not only for siRNA delivery but also for chemotherapy-resistant TNBC therapy.

Docetaxel-Loaded Chitosan-Cholesterol Conjugate-Based Self-Assembled Nanoparticles for Overcoming Multidrug Resistance in Cancer Cells.

Cholesteryl hemisuccinate (CHS)-conjugated chitosan (CS)-based self-assembled nanoparticles (NPs) were developed for enhancing the intracellular uptake of docetaxel in multidrug resistance (MDR)-acquired cancer cells. CHS-CS was successfully synthesized and self-aggregation, particle size, zeta potential, drug entrapment efficiency, and in vitro drug release of docetaxel-loaded CHS-CS NPs were tested. The optimized NPs had a mean hydrodynamic diameter of 303 nm, positive zeta potential of 21.3 mV, and spherical shape. The in vitro release of docetaxel from the optimized CHS-CS NPs in different pH medium (pH 6.0 and 7.4) revealed that the release was improved in a more acidic condition (pH 6.0), representing a tumor cell's environment. The superior MDR-overcoming effect of docetaxel-loaded CHS-CS NPs, compared with docetaxel solution, was verified in anti-proliferation and cellular accumulation studies in MDR-acquired KBV20C cells. Thus, CHS-CS NPs could be potentially used for overcoming the MDR effect in anticancer drug delivery.

Systemic Delivery of Aptamer-Conjugated XBP1 siRNA Nanoparticles for Efficient Suppression of HER2+ Breast Cancer.

siRNA therapeutics as an emerging class of drug development is successfully coming to clinical utilization. The RNA-based therapy is widely utilized to explore the mechanism and cure a variety of gene-specific diseases. Tumor is an oncogene-driven disease; many genes are related to tumor progression and chemoresistance. Although human epidermal growth factor receptor 2 (HER2)-targeted monoclonal antibody therapy has dramatically improved the survival rate, chemotherapy remains essential to HER2-positive (HER2+) breast cancer patients. Recently, X-box binding protein 1 (XBP1) has been involved in triple-negative breast cancer (TNBC) chemoresistance and progression, but its function in HER2+ breast cancer is poorly explored. Here, we silenced XBP1 expression using RNase-resistant RNA nanoparticles (NPs). Intravenous injection of RNA NPs with HER2-specific aptamers resulted in strong binding to tumors but not to healthy tissues. XBP1 deletion by RNA NPs impaired angiogenesis and inhibited cell proliferation, significantly suppressed breast cancer growth, and promoted the sensitization of chemotherapy in an HER2+ breast cancer mouse model. Overall, these results reveal the function of XBP1 in HER2+ breast cancer development and chemoresistance and imply that targeting XBP1 by RNA NPs may offer an easy and promising strategy for a combination treatment of breast cancer in the future.

Monoterpenes-containing PEGylated transfersomes for enhancing joint cavity drug delivery evidenced by CLSM and double-sited microdialysis.

The synovial tissues are natural sites of drug delivery for the treatment of rheumatoid arthritis. Our previous study showed that mixed monoterpenes edge-activated PEGylated transfersomes (MMPTs) could significantly enhance the percutaneous absorption of sinomenine (SIN), an anti-inflammation drug. The aim of this study was to investigate the potential of MMPTs for delivery of SIN to the synovial tissues in joint cavities. To this end, conventional liposomes (LPSs) were used as a reference. Transmission electron microscope, constant pressure extrusion method, and differential scanning calorimetry (DSC) were used for physicochemical characterization of the formulations. Confocal laser scanning microscopy (CLSM) and double-sited microdialysis coupled with LC-MS/MS were exploited to study the distribution of MMPTs in different skin layers and pharmacokinetics of SIN in the blood and the joint cavities. The results showed that mixed monoterpenes could significantly enhance the elasticity of MMPTs, evidenced by a decrease in the main transition temperature (Tm) and transition enthalpy (△H). CLSM analyses demonstrated that MMPTs were distributed in deep layers of the skin, indicating that MMPTs might transport SIN through the skin. In contrast, LPSs were confined in the stratum corneum, which deterred SIN from penetrating through the skin. The results from double-sited microdialysis pharmacokinetics showed that in the joint cavities the steady state concentration (Css) and AUC0→t of SIN from MMPTs were 2.1-fold and 2.5-fold of those from LPSs, respectively. In contrast, in the blood the Css and AUC0→t of SIN from MMPTs were about 1/3 of those from LPSs. This study suggested that MMPTs could enhance the delivery of SIN to the joint cavities. A combination of CLSM and double-sited microdialysis could give an insight into the mechanism of transdermal and local drug delivery.

Dual oligopeptides modification mediates arsenic trioxide containing nanoparticles to eliminate primitive chronic myeloid leukemia cells inside bone marrow niches.

Chronic myeloid leukemia (CML) is one type of hematopoietic stem cell diseases. Although BCR-ABL1 tyrosine kinase inhibitors are remarkably effective in inducing remission in chronic phase patients, they are not curative in a majority of patients due to their failure to eradicate residual CML stem/progenitor cells, which reside in bone marrow niches. Here, we presented novel dual oligopeptides-conjugated nanoparticles and demonstrated their effective delivery of arsenic trioxide in bone marrow niches for the elimination of primitive CML cells. We encapsulated As-Ni transitional metal compounds into polymeric nanoparticles based on the reverse micelle rationale. The loading density and stability of arsenic trioxide in nanoparticles were improved. In vitro experiments demonstrated that dual oligopeptides conjugated nanoparticles could deliver arsenic trioxide into bone marrow niches including endosteal niches and vascular niches. The colony-forming activity of CML cells was remarkably restrained in the presence of metaphyseal bone fragments pre-incubated with bone marrow niche targeted arsenic nanoparticles. The in vitro vascular niche model suggested that CML cell proliferation was also successfully inhibited through a tight contact with HUVECs, which were pre-treated using niche-targeted arsenic nanoparticles. This bone marrow niche targeted delivery strategy has a potential usage for the treatment of CML and other malignant hematologic disorders originated from the bone marrow.

Intranasal administration of pullulan-based nanoparticles for enhanced delivery of adriamycin into the brain: in vitro and in vivo evaluation.

Intranasal (i.n.) administration is an efficient route for enhancing drug delivery to the brain, bypassing the blood-brain barrier (BBB) and eliminating systemic side effects. The purpose of this study was to investigate the nose-to-brain delivery efficiency of adriamycin (ADM) loaded in cholesterol-modified pullulan self-assembled nanoparticles (CHSP-SAN) via i.n. administration. The prepared nanodrugs (ADM-CHSP-SAN) were characterized as uniform size (112.8±1.02 nm), high drug loading capacity (7.65±0.58 %), and sustained release. CHSP-SAN showed good biocompatibility and low toxicity on HBMEC and C6 cells. The enhanced delivery of ADM across the BBB with CHSP-SAN was demonstrated by the reduced half maximal inhibitory concentration (IC50) value and the increased apoptosis proportion of C6 cells. The pharmacokinetics of ADM-CHSP-SAN was accessed by cerebral microdialysis technique. The pharmacokinetic results showed higher peak concentration (Cmax), area under the curve (AUC0-12h) and shorter peak time (Tmax) after i.n. administration that after intravenous (i.v.) administration. The i.n. administration of CHSP-SAN greatly increased ADM availability in cerebral tissue compared to that of ADM solution. Collectively, CHSP-SAN strikingly increased ADM transport across the BBB and improved its availability in brain via i.n. administration.

Angiopep-2-Conjugated "Core-Shell" Hybrid Nanovehicles for Targeted and pH-Triggered Delivery of Arsenic Trioxide into Glioma.

The poor capability of drugs to permeate through the blood-brain barrier (BBB) and further release inside glioma greatly limits the curative effects of glioma chemotherapies. In this study, we prepared angiopep-2-conjugated liposome-silica hybrid nanovehicles for targeted delivery and increased the permeation of arsenic trioxide (ATO) in glioma. Polyacrylic acid (PAA) was grafted on mesoporous silica nanoparticles (MSN) for pH-sensitive release and supporting the lipid membrane. The prepared "core-shell" nanovehicles (ANG-LP-PAA-MSN) were characterized with uniform size, high drug loading efficiency (8.19 ± 0.51%), and superior pH-sensitive release feature. From the experiments, the enhanced targeted delivery of ATO by ANG-LP-PAA-MSN (ANG-LP-PAA-MSN@ATO) was evidenced by the improvement of transport, enhanced cellular uptake, and apoptosis in vitro. In addition, the pharmacokinetic study was creatively carried out through the blood-glioma synchronous microdialysis and revealed that the half-life ( t1/2) of blood and glioma tissue in the ANG-LP-PAA-MSN@ATO treatment group was extended by 1.65 and 2.34 times compared with the ATO solution group (ATO-Sol). The targeting efficiency of ANG-LP-PAA-MSN@ATO (24.96%) was dramatically stronger than that of the ATO-Sol (5.94%). Importantly, ANG-LP-PAA-MSN@ATO had a higher accumulation (4.6 ± 2.6% ID per g) in tumor tissues and showed a better therapeutic efficacy in intracranial C6 glioma bearing rats. Taken together, the blood-glioma synchronous microdialysis was successful used for the pharmacokinetic study and real-time monitoring of drug concentrations in blood and glioma; ANG-LP-PAA-MSN could be a promising targeted drug delivery system for glioma therapy.

Low molecular weight chitosan-based conjugates for efficient Rhein oral delivery: synthesis, characterization, and pharmacokinetics.

OBJECTIVE: This article aims to design low molecular weight chitosan (LMWC)-based conjugates of Rhein (RH) by means of an amino acid linker (Alanine) for improved solubility and enhanced bioavailability. SIGNIFICANCE: Rhein is a potential candidate for the therapy of kidney disease. However, the poor solubility, inadequate bioavailability, and lack of proper formulation restrict its clinical applicability. LMWC-drug conjugates offer the potential to improve the water-solubility of RH, increase its oral absorption, and thereby enhance its bioavailability. METHODS: The conjugates were synthesized via a carbodiimide reaction and confirmed using UV-vis, FTIR, and 1H-NMR spectroscopy. The water-solubility and in vitro release properties were evaluated. Free RH and RH-LMWC conjugates were administered at an equivalent oral gavage dose of RH at 35 mg/kg for pharmacokinetic studies in Sprague Dawley rats. RESULTS: The conjugates with RH content of 9.65% were successfully synthesized and featured a satisfactory water-solubility of 9.73 mg/mL, which exhibited a sustained release pattern over 72 h, and the enzymes present may promote the degradation of the conjugate to increase the release of Rhein. Oral administration of RH-LMWC conjugates to rats led to seven-folds and 3.1-folds increase in the T1/2 and AUC0-∞, respectively, as compared to RH suspension. CONCLUSION: The present work demonstrated that the RH-LMWC conjugates exhibited sustained release properties with outstanding oral bioavailability enhancements compared to administration of RH itself. Potentially, RH-LMWC conjugates may serve as a promising lead for developing a new platform for RH oral delivery.

Chemotherapy Sensitizes Therapy-Resistant Cells to Mild Hyperthermia by Suppressing Heat Shock Protein 27 Expression in Triple-Negative Breast Cancer.

Purpose: Triple-negative breast cancer (TNBC) is a clinically aggressive disease with poor prognosis. Conventional chemotherapeutics are generally able to shrink the tumor mass, but often fail to completely eradicate cancer stem-like cells (CSCs) that are responsible for high risk of relapse and frequent metastases. In this study, we examined thermal sensibility of CSCs, developed an approach that enabled concurrent elimination of both the bulk of cancer cells and CSCs, and investigated the underlying mechanism.Experimental Design: We designed a platform consisting of gold nanoparticle-coated porous silicon microparticle (AuPSM) that was also loaded with docetaxel micelles (mDTXs) to enable concurrent killing of the bulk of cancer cells by released mDTX and CSCs by mild hyperthermia upon stimulation of AuPSM with near infrared. In addition, we examined the role of heat shock proteins in sensitizing CSC killing. Finally, we applied mDTX-loaded AuPSM to treat mice with SUM159 and 4T1 orthotopic tumors and evaluated tumor growth and tumor metastasis.Results: MDA-MB-231 and SUM159 TNBC cells treated with mDTX-loaded AuPSM and mild hyperthermia displayed significantly reduced efficiencies in mammosphere formation than those treated with mDTX alone or mild hyperthermia alone. Combination treatment also completely inhibited SUM159 orthotopic tumor growth and 4T1 tumor metastasis. Mechanistically, DTX treatment suppressed expression of heat shock protein 27 in cancer cells including the CSCs, rendering cells sensitive to mild hyperthermia.Conclusions: Our results indicate that chemotherapy sensitizes CSC to mild hyperthermia. We have developed an effective therapeutic approach to eliminate therapy-resistant cells in TNBC. Clin Cancer Res; 24(19); 4900-12. ©2018 AACR.

Effect of ß-elemene on the kinetics of intracellular transport of d-luciferin potassium salt (ABC substrate) in doxorubicin-resistant breast cancer cells and the associated molecular mechanism.

In order to explore the mechanism of the reversing multidrug resistance (MDR) phenotypes by ß-elemene (ß-ELE) in doxorubicin (DOX)-resistant breast cancer cells (MCF-7/DOX), both the functionality and quantity of the ABC transporters in MCF-7/DOX were studied. Bioluminescence imaging (BLI) was used to study the efflux of d-luciferin potassium salt, the substrate of ATP-binding cassette transporters (ABC transporters), in MCF-7/DOX cells treated by ß-ELE. At the same time three major ABC transport proteins and genes-related MDR, P-glycoprotein (P-gp, ABCB1) and multidrug resistance-associated protein 1 (MRP, ABCC1) as well as breast cancer resistance protein (BCRP, ABCG2) were analyzed by q-PCR and Western blot. To investigate the efflux functionality of ABC transporters, MCF-7/DOXFluc cell line with stably-overexpressed luciferase was established. BLI was then used to real-time monitor the efflux kinetics of d-luciferin potassium salt before and after MCF-7/DOXFluc cells being treated with ß-ELE or not. The results showed that the efflux of d-luciferin potassium salt from MCF-7/DOXFluc was lessened when pretreated with ß-ELE, which means that ß-ELE may dampen the functionality of ABC transporters, thus decrease the efflux of d-fluorescein potassium or other chemotherapies which also serve as the substrates of ABC transporters. As the effect of ß-ELE on the expression of ABC transporters, the results of q-PCR and Western blot showed that gene and protein expression of ABC transporters such as P-gp, MRP, and BCRP were down-regulated after the treatment of ß-ELE. To verify the efficacy of ß-ELE on reversing MDR, MCF-7/DOX cells were treated with the combination of DOX and ß-ELE. MTT assay showed that ß-ELE increased the inhibitory effect of DOX on the proliferation of MCF-7/DOX, and the IC50 of the combination group was much lower than that of the single DOX or ß-ELE treatment. In all, ß-ELE may reverse MDR through the substrates of ABC transporters by two ways, to lessen the ABC protein efflux by weakening their functionality, or to reduce the quantity of ABC gene and protein expression.

A Novel DNA Aptamer for Dual Targeting of Polymorphonuclear Myeloid-derived Suppressor Cells and Tumor Cells.

Aptamers have the potential to be used as targeting ligands for cancer treatment as they form unique spatial structures. Methods: In this study, a DNA aptamer (T1) that accumulates in the tumor microenvironment was identified through in vivo selection and validation in breast cancer models. The use of T1 as a targeting ligand was evaluated by conjugating the aptamer to liposomal doxorubicin. Results: T1 exhibited a high affinity for both tumor cells and polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs). Treatment with T1 targeted doxorubicin liposomes triggered apoptosis of breast cancer cells and PMN-MDSCs. Suppression of PMN-MDSCs, which serve an immunosuppressive function, leads to increased intratumoral infiltration of cytotoxic T cells. Conclusion: The cytotoxic and immunomodulatory effects of T1-liposomes resulted in superior therapeutic efficacy compared to treatment with untargeted liposomes, highlighting the promise of T1 as a targeting ligand in cancer therapy.

Targeted drug delivery for tumor therapy inside the bone marrow.

Bone marrow is the primary hematopoietic organ, which is involved in multiple malignant diseases including acute and chronic leukemia, multiple myeloma, myelodysplastic syndromes, and bone metastases from solid tumors. These malignancies affect normal homeostasis and reshape the bone marrow microenvironment. There are limited treatment options for them because of their inevitable aggravation. The current systemic administration of anticancer agents is difficult to achieve ideal therapeutic dose to suppress tumor growth at bone marrow diseased sites, and is always associated with a high incidence of relapse and severe side effects. The limitations of current treatments urge scientists to develop bone marrow targeted drug delivery systems intended for the treatment of diseased bone marrow, which can improve the efficacy of therapeutic agents and reduce their dose-limiting systemic side effects on healthy tissues. In this review we first present the current opinions on bone marrow vasculature, as well as the molecular and structural interactions between tumor cells and the diseased bone marrow. In the second part, we highlight the different design rationales and strategies of bone marrow delivery systems and their therapeutic applications for the treatment of malignancies inside the bone marrow.