Glucocorticoid Receptor-Targeted Liposomal Codelivery of Lipophilic Drug and Anti-Hsp90 Gene: Strategy to Induce Drug-Sensitivity, EMT-Reversal, and Reduced Malignancy in Aggressive Tumors

Gold nanoparticles-based targeted delivery of rapamycin and Olaparib to breast cancer: An in vitro and in vivo approach

Triple negative form of breast cancer (abbreviated as TNBC) is considered as the most aggressive form causing high mortality worldwide. Different treatment modalities such as chemotherapy, surgery, hormonal therapy and radiation therapy are employed for eliminating breast cancer, which are associated with many limitations. Therefore, considering the significance of metal nanoparticles in the biomedical sector, especially gold nanoparticles, in the current manuscript, we have designed and developed a combinatorial approach for synthesizing two types of gold (Au) nanoformulations (Au-Dex-MUA-Rapa, Au-Dex-MUA-Ola) using 11-mercaptoundecanoic acid (MUA), dexamethasone (Dex) (glucocorticoid receptor targeted molecule) along with rapamycin (Rapa: inhibitor of mTOR) or olaparib (Ola: inhibitor of PARP) against TNBC. These gold nanoformulations were characterized thoroughly using several analytical techniques such as TEM, spectroscopy, DLS, HPLC and ICPOES. The in vitro MTT assays (normal cells: HEK-293 and CHO) and ex vivo CAM assay displays the biocompatible properties of the conjugated gold nanoformulations. Further, the anticancer properties of the conjugated gold nanoformulations in TNBC cells (MDA-MB-231) were evaluated through several in vitro experiments along with plausible mechanism of action. The intraperitoneal administration of gold nanoformulations into the breast tumor bearing BALB/c mice inhibits the tumor growth and increases their survivability. Additionally, we have investigated the plausible mechanistic studies behind the anticancer properties of the conjugated gold nanoformulations. Finally, we have found the non-toxic nature of these nanoformulations at therapeutic dose. Considering the above results, the conjugated gold nanoformulations could be used as an alternative therapeutic strategy for the treatment of breast carcinoma in near future.

Glucocorticoid Receptor-Targeted Nanoliposome for STAT3 Inhibition-Led Myeloid-Derived Suppressor Cell Modulation and Efficient Colon Cancer Treatment

STAT3 is an important protein responsible for cellular proliferation, motility, and immune tolerance and is hyperactive in colorectal cancer, instigating metastasis, cellular proliferation, migration, as well as inhibition. It helps in proliferation of myeloid-derived suppressor cells (MDSCs), which within the tumor microenvironment (TME) suppress T cells to encourage tumor growth, metastasis, and resistance to immunotherapy, besides playing dynamic role in regulating macrophages within the tumor. Thus, MDSC is a potential target to augment immune surveillance within the TME. Herein, we report targeting both colorectal cancer and MDSCs using a glucocorticoid receptor (GR)-targeted nanoliposomal formulation carrying GR-ligand, dexamethasone (Dex), and a STAT3 inhibitor, niclosamide (N). Our main objective was to selectively inhibit STAT3, the key immunomodulatory factor in most TME-associated cells including MDSCs, and also repurpose the use of this antihelminthic, low-cost drug N for cancer treatment. The resultant formulation D1XN exhibited better tumor regression and survivability compared to GR nontargeted formulation. Further, bone marrow cell-derived MDSCs were engineered by D1XN treatment ex vivo and were inoculated back to tumor-bearing mice. Significant tumor growth inhibition with enhanced antiproliferative immune cell signatures, such as T cell infiltration, decrease in Treg cells, and increased M1/M2 macrophage ratio within the TME were observed. This reveals the effectiveness of engineered MDSCs to modulate tumor surveillance besides reversing the aggressiveness of the tumor. Therefore, D1XN and D1XN-mediated engineered MDSCs alone or in combination can be considered as potent selective chemo-immunotherapeutic nanoliposomal agent(s) against colorectal cancer.

Liposomal drug delivery systems for organ-specific cancer targeting: early promises, subsequent problems, and recent breakthroughs

INTRODUCTION

Targeted liposomal systems for cancer intention have been recognized as a specific and robust approach compared to conventional liposomal delivery systems. Cancer cells have a unique microenvironment with special over-expressed receptors on their surface, providing opportunities for discovering novel and effective drug delivery systems using active targeting.

AREAS COVERED

Smartly targeted liposomes, responsive to internal or external stimulations, enhance the delivery efficiency by increasing accumulation of the encapsulated anti-cancer agent in the tumor site. The application of antibodies and aptamers against the prevalent cell surface receptors is a potent and ever-growing field. Moreover, immuno-liposomes and cancer vaccines as adjuvant chemotherapy are also amenable to favorable immune modulation. Combinational and multi-functional systems are also attractive in this regard. However, potentially active targeted liposomal drug delivery systems have a long path to clinical acceptance, chiefly due to cross-interference and biocompatibility affairs of the functionalized moieties.

EXPERT OPINION

Engineered liposomal formulations have to be designed based on tissue properties, including surface chemistry, charge, and microvasculature. In this paper, we aimed to investigate the updated targeted liposomal systems for common cancer therapy worldwide.

Bis-arylidene oxindoles for colorectal cancer nanotherapy

Oxindoles are potent anti-cancer agents and are also used against microbial and fungal infections and for treating neurodegenerative diseases. These oxindoles are earlier established as estrogen receptor (ER)-targeted agents for killing ER (+) cancer cells. Our previously developed bis-arylidene oxindole, Oxifen (OXF) exhibits effective targeting towards ER (+) cancer cells which has a structural resemblance with tamoxifen. Herein, we have designed and synthesized few structural analogues of OXF such as BPYOX, ACPOX and ACPOXF to examine its cytotoxicity in different cancer as well as non-cancer cell lines and its potential to form self- aggregates in aqueous solution. Among these series of molecules, ACPOXF showed maximum toxicity in colorectal cancer cell line which are ER (-) but it also kills non-cancer cell line HEK-293, thereby reducing its cancer cell selectivity. Incidentally, ACPOXF exhibits self-aggregation, without the help of a co-lipid with nanometric size in aqueous solution. ACPOXF self-aggregate was co-formulated with glucocorticoid receptor (GR) synthetic ligand, dexamethasone (Dex) (called, ACPOXF-Dex aggregate) which could selectively kill ER (-) colorectal cancer cells and also could increase survivability of colon-tumour bearing mice. ACPOXF-Dex induced ROS up-regulation followed by apoptosis through expression of caspase-3. Further, we observed upregulation of antiproliferative factor, p53 and epithelial-to-mesenchymal (EMT) reversal marker E-cadherin in tumour mass. In conclusion, a typical structural modification in ER-targeting Oxifen moiety resulted in its self-aggregation that enabled it to carry a GR-ligand, thus broadening its selective antitumor property especially as colon cancer therapeutics.

Steroid hormone receptor based gene delivery systems as potential oral cancer therapeutics

Glucocorticoid and Mineralocorticoid receptors are principally ligand-dependent intracellular transcription factors that are known to influence the development and growth of many human cancers. Our study investigates the potential of these receptors to act as a target for oral cancer treatment since findings in this regard are sparse till date. Leveraging the aberrant behavior of steroid hormone receptors (SHRs) in cancer, we have targeted oral cancer cells in 2D-culture using liposomes containing both synthetic as well as crude, natural SHR ligands isolated from an aqueous Indian medicinal plant. Lipoplexes thus formulated demonstrated targeted transfectability as indicated by expression of green fluorescent protein. Transfection of oral squamous cell carcinoma cells with exogenous, anticancer gene p53 lipoplexed with crude saponin-based liposome induced apoptosis of cancer cells via regulation of BAX and B-cell leukemia/lymphoma-2 (BCL2) protein levels at levels comparable with pre-established delivery systems based on synthetic SHR ligands. Our findings strongly indicate a possibility of developing plant saponin-based inexpensive delivery systems which would target cancer cells selectively with reduced risks of off target delivery and its side effects.

Glucocorticoid receptor mediated sensitization of colon cancer to photodynamic therapy induced cell death

Photodynamic therapy (PDT) is a clinically approved, non-invasive alternate cancer therapy. A synthetic glucocorticoid (GC), dexamethasone (Dex) has previously been demonstrated to sensitize cancer cells to chemotherapy. However, to the best of our knowledge, the sensitization effect of GCs on PDT has not yet been investigated. We hypothesized that glucocorticoid receptor (GR) targeting can selectively make cancer cells more sensitive to PDT treatment, as PDT induces hypoxia wherein GR-activity gets enhanced. In addition, Dex was reported to act against the PDT-induced cell survival pathways like HIF-1α, NRF2, NF-κB, STAT3 etc. Thus, both the treatments can complement each other and may result in increasing the effectiveness of combination therapy. Hence, in this study, we developed liposomal formulations of our previously reported PDT agent P-Nap, either alone (D1P-Nap) or in combination with Dex (D1XP-Nap) to elucidate the sensitization effect. Interestingly, our RT-PCR results in hypoxic conditions showed down-regulation of HIF-1α and over expression of GR-activated genes for glucose-6-phosphatase (G6Pase) and PEPCK enzymes, indicating prominent GR-transactivation. We also observed higher phototoxicity in CT26.WT cells treated with D1XP-Nap PDT under hypoxic conditions as compared to normoxic conditions. These effects were reversed when cells were pre-treated with RU486, a competitive inhibitor of GCs. Moreover, our in vivo findings of subcutaneous tumor model of Balb/C mice for colon cancer revealed a significant decrease in tumor volume as well as considerable enhancement in the survivability of PDT treated tumor-bearing mice when Dex was present in the formulation. A high Bax/Bcl-xL ratio, high p53 expression, enhanced E-cadherin expression and down-regulation of pro-tumorigenic transcription factors NF-κB and c-Myc were found in tumor lysates from mice treated with D1XP-Nap under PDT, indicating GR-mediated sensitization of the tumor to PDT-induced cell death and enhancement of life-span for tumor bearing mice.

Cationic lipid-conjugated bis-arylidene oxindole derivatives as broad-spectrum breast cancer-selective therapeutics

Breast cancer is a heterogeneous malignancy with wide-ranging variations in therapeutic responses, overall survival etc. Major challenges for available chemotherapeutic agents in achieving clinical success are in maintaining systemic bio-distribution and avoiding non-specific adverse effects. Bis-arylidene oxindoles are estrogen receptor (ER)-selective bioactive molecules with moderate potency. In here, we have designed, synthesized and evaluated a series of twin aliphatic chain cationic lipid-conjugated bis-arylidene oxindole molecules with variations in nature of linker, lengths of carbon spacer and hydrophobic twin chains. We observed that among the various structural analogues, C8 twin-chain containing molecules, PGC8, S2C8 and S3C8 showed effective cancer cell-selective cytotoxicity in different cancer cell lines with an IC₅₀ ranging from 4 to 7 µM. These molecules selectively induced apoptosis, ROS production and cell cycle inhibition at G1/S phase in ER + breast cancer cells but not in non-cancer cells. Additionally, these molecules formed homogenous self-assemblies exhibiting effective hydrodynamic diameter with positive surface charge. The self-assemblies also showed prominent cancer cell-selective uptake and DNA-binding abilities. Hence, we have shown successful incorporation of dexamethasone to the self-assemblies, and its enhanced cytotoxicity even in ER-negative breast cancer cells. All these results indicate that PGC8, S2C8 and S3C8 molecules, albeit their potent and selective ER-positive anti-breast cancer activity, can be repurposed as targeted delivery systems and hold promise as unique, broader spectrum breast cancer cell-selective therapeutic payloads.

Modification of α-Tocopherol Succinate with a Tumor-targeting Peptide Conjugate Enhances the Antitumor Efficacy of a Paclitaxel-loaded Lipid Aggregate

Paclitaxel (PTX) is a widely used chemotherapeutic agent in the clinic. However, its clinical benefit is limited due to its low water solubility, off-target toxicity, and for being a multidrug-resistant (MDR) substrate. To overcome these limitations in this study, a tumor-targeting peptide (CRGDK peptide, a ligand for NRP-1 receptor) conjugate of α-tocopheryl succinate (α-TOS) was synthesized and modified on PTX-loaded lipid aggregate (TL-PTX) to leverage the benefits of α-TOS, which include a) anti-cancer activity, b) increased PTX loading, and c) inhibition of MDR activity. Use of peptide conjugate of α-TOS (α-TOS-CRGDK) in lipid aggregate increased PTX entrapment efficiency by 20%, helped in NRP-1 specific cellular uptake and significantly enhanced apoptotic and cell killing activity (p <0.01) of PTX compared to control formulation (CL-PTX) by inhibiting MDR-activity in melanoma resulting in ∼70% increment in overall survival of melanoma tumor-bearing mice. In conclusion, CRGDK- α-TOS conjugate in association with PTX-loaded liposome provided a unique NRP-1 targeted, drug-resistant reversing anticancer regimen for treating aggressive melanoma.

Well-Defined pH-Responsive Self-Assembled Block Copolymers for the Effective Codelivery of Doxorubicin and Antisense Oligonucleotide to Breast Cancer Cells

The worldwide steady increase in the number of cancer patients motivates the development of innovative drug delivery systems for combination therapy as an effective clinical modality for cancer treatment. Here, we explored a design concept based on poly(ethylene glycol)-b-poly(2-(dimethylamino)ethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate-formylbenzoic acid) [PEG-b-PDMAEMA-b-P(HEMA-FBA)] for the dual delivery of doxorubicin (DOX) and GTI2040 (an antisense oligonucleotide for ribonucleotide reductase inhibition) to MCF-7 breast cancer cells. PEG-b-PDMAEMA-b-PHEMA, the precursor copolymer, was prepared through chain extensions from a PEG-based macroinitiator via two consecutive atom transfer radical polymerization (ATRP) steps. Then, it was modified at the PHEMA block with 4-formylbenzoic acid (FBA) to install reactive aldehyde moieties. A pH-responsive polymer-drug conjugate (PDC) was obtained by conjugating DOX to the polymer structure via acid-labile imine linkages, and subsequently self-assembled in an aqueous solution to form DOX-loaded self-assembled nanoparticles (DOX-SAN) with a positively charged shell. DOX-SAN condensed readily with negatively charged GTI2040 to form GTI2040/DOX-SAN nanocomplexes. Gel-retardation assay confirmed the affinity between GTI2040 and DOX-SAN. The GTI2040/DOX-SAN nanocomplex at N/P ratio of 30 exhibited a volume-average hydrodynamic size of 136.4 nm and a zeta potential of 21.0 mV. The pH-sensitivity of DOX-SAN was confirmed by the DOX release study based on the significant cumulative DOX release at pH 5.5 relative to pH 7.4. Cellular uptake study demonstrated favorable accumulation of GTI2040/DOX-SAN inside MCF-7 cells compared with free GTI2040/DOX. In vitro cytotoxicity study indicated higher therapeutic efficacy of GTI2040/DOX-SAN relative to DOX-SAN alone because of the downregulation of the R2 protein of ribonucleotide reductase. These outcomes suggest that the self-assembled pH-responsive triblock copolymer is a promising platform for combination therapy, which may be more effective in combating cancer than individual therapies.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Enriched pharmacokinetic behavior and antitumor efficacy of thymoquinone by liposomal delivery

Background: Thymoquinone (TQ) has potential anti-inflammatory, immunomodulatory and anticancer effects but its clinical use is limited by its low solubility, poor bioavailability and rapid clearance. Aim: To enhance systemic bioavailability and tumor-specific toxicity of TQ. Materials & methods: Cationic liposomal formulation of TQ (D1T) was prepared via ethanol injection method and their physicochemical properties, anticancer effects in orthotopic xenograft pancreatic tumor model and pharmacokinetic behavior of D1T relative to TQ were evaluated. Results: D1T showed prominent inhibition of pancreatic tumor progression, significantly greater in vivo absorption, approximately 1.5-fold higher plasma concentration, higher bioavailability, reduced volume of distribution and improved clearance relative to TQ. Conclusion: Encapsulation of TQ in cationic liposomal formulation enhanced its bioavailability and anticancer efficacy against xenograft pancreatic tumor.

Glucocorticoid receptor-targeted liposomal delivery system for delivering small molecule ESC8 and anti-miR-Hsp90 gene construct to combat colon cancer

High mortality rate in colon cancer patients is often attributed to late diagnosis. To overcome the conventional chemotherapy associated challenges, chemotherapeutic drugs (single or combination) or genetic drugs are often delivered using ligand-modified delivery systems that selectively target over expressed receptors or particular receptors that act abnormally in cancer cells. In the current investigation, first we assessed anti-colon cancer effect of a cationic estrogenic molecule, ESC8 which was earlier shown to act against estrogen receptor (ER) ± breast cancer cells. We found that against both colon and breast cancer cells the anticancer activity is intervened by AMPK-mTOR pathway and at the same time it acts as anti-angiogenic agent. It also showed enhancement of mesenchymal-to-epithelial (MET) transition as well as reduction of cyclin D in both cells. Earlier we demonstrated the use of glucocorticoid receptor (GR) targeted cationic liposomal delivery system carrying anti-Hsp90 plasmid and ESC8 to act as potent anti-skin cancer therapeutics. As ESC8 demonstrated anti-colon cancer effect in vitro, in here, we used the same GR-targeted liposomal formulation but carrying a more fusogenic cationic lipid D1 and used against colon tumor orthotopic model in mice. We show that GR targeted formulation (D1XE-Hsp90) exhibited efficient cellular uptake, transfection and selective cytotoxicity in colon cancer cells, tumor-targeted bio-distribution and enhanced survivability, reduced tumor size in orthotopic colon tumor-bearing mice. The tumor sections exhibited reduced tumor proliferation as well as neo-vascularization, thus supporting the holistic antitumor effect of the D1XE-Hsp90 formulation. Over all our results establish the GR-targeted D1XE-Hsp90 formulation as potent anti-colon cancer therapeutics.

Self-Assembling Derivative of Hydrocortisone as Glucocorticoid Receptor-Targeted Nanotherapeutics for Synergistic, Combination Therapy against Colorectal Tumor

Hydrocortisone, a natural glucocorticoid secreted by adrenal and extra-adrenal tissues, locally governs the transcription of genes involved in inflammation, immune response, metabolism, and energy homeostasis via binding to its cognate glucocorticoid receptor (GR). In this study, we show that modified hydrocortisone (HC16), a cancer-selective cytotoxic molecule, showed synergism in combination with drugs like Doxorubicin and docetaxel, self-assembled into vesicles, entrapped docetaxel and complexed with anti-cancer plasmid DNA for enhanced killing of cancer cells. These vesicles exhibited GR-mediated nuclear localization, delivery of the p53 gene, and also inhibited cell viability selectively in RKO, HCT15, and CT26 colon cancer cells but not in normal cells like CHO and HEK293T. Apart from exerting its own anti-cancer activity, the self-assembled HC16 vesicles loaded with docetaxel sensitized the cancer cells to its drug cargo by downregulating the drug metabolizing CYP3A4 gene. This indirectly reduces the risk of nonspecific adverse effects in normal cells, as the viability of sensitized cancer cells could be significantly reduced even in low doses of cytotoxic docetaxel. The near infrared (NIR)-dye-associated self-assemblies accumulated in a colon tumor with higher orders of NIR intensity compared to those in a colon of healthy mice. Thereafter, the treatment of HC16-docetaxel-p53 vesicle/DNA complex led to significant tumor regression, which resulted in a cecum/body weight ratio in tumor-bearing mice similar to that of healthy mice measured at 24 h postcompletion of treatment. There was an up to 2.5-fold enhancement in the overall survivability of colon-tumor-bearing mice treated with HC16-docetaxel-p53 vesicle/DNA complexes when compared against the pristine docetaxel-treated groups. Further, the HC16-docetaxel-p53 vesicle/DNA complex-treated group showed reduced nuclear accumulation of cell proliferation marker Ki67, reduced protein levels of prosurvival and mesenchymal proteins like Bcl-2, PARP, vimentin, and N-cadherin, and increased the levels of pro-apoptotic activated caspases as compared to the pristine docetaxel-treated groups. The therapeutic package described herein is expected to find future use as a rational, multifaceted, GR-targeted approach for inhibiting colon tumor progression.

Efficient anti-tumor nano-lipoplexes with unsaturated or saturated lipid induce differential genotoxic effects in mice

Cationic lipids are well-known excipients for nanometric liposomal gene delivery systems. However, because of the suspected, collateral toxicity in normal cells, the use of cationic lipids for the treatment of human tumor is largely limited. Recently, we developed a glucocorticoid receptor (GR)-targeted liposomal, anticancer delivery system (DXE nano-lipoplex), which carried cationic lipid of saturated twin aliphatic chains. It exhibited efficient anti-tumor effect in aggressive and drug-resistant tumor models. Toward exploring lipoplex's human clinical use, we incorporated another nano-lipoplex (D1XE) group that carried cationic lipid with one of its aliphatic chain carrying unsaturation and compared in vivo genotoxicological profiling-based safety assessment and the respective anti-tumor efficacy of the lipoplexes. Thus, both the lipoplexes differ only by the chemical identity of one of their constituent cationic lipid. Unsaturated aliphatic chains in lipid generally impart efficient cell surface fusogenic property in lipid formulations. Herein, we report that nanoplex with unsaturated cationic lipid (D1XE) exhibited better physical appearance with less flocculent behavior than nanoplex with saturated lipid (DXE). Upon multiple injections, D1XE nanoplex imparted better tumor regression but most importantly, exhibited much lower overall toxicity (e.g. genotoxicity, weight loss, etc.) than DXE nanoplex. With a higher antitumor effect but a lower genotoxic effect, D1XE is proved to be a better nanoplex than DXE for the potential clinical trial. Thus, this study clearly delineates the importance of incorporating a constituent lipid that carries a single unsaturated aliphatic chain toward developing efficient anti-tumor nano-lipoplexes with reduced genotoxicity.

Pseudopterosin Inhibits Proliferation and 3D Invasion in Triple-Negative Breast Cancer by Agonizing Glucocorticoid Receptor Alpha

Pseudopterosin, produced by the sea whip of the genus Antillogorgia, possesses a variety of promising biological activities, including potent anti-inflammatory effects. However, few studies examined pseudopterosin in the treatment of cancer cells and, to our knowledge, the ability to inhibit triple-negative breast cancer (TNBC) proliferation or invasion has not been explored. Thus, we evaluated the as-yet unknown mechanism of action of pseudopterosin: Pseudopterosin was able to inhibit proliferation of TNBC. Interestingly, analyzing breast cancer cell proliferation after knocking down glucocorticoid receptor α (GRα) revealed that the antiproliferative effects of pseudopterosin were significantly inhibited when GRα expression was reduced. Furthermore, pseudopterosin inhibited the invasion of MDA-MB-231 3D tumor spheroids embedded in an extracellular-like matrix. Remarkably, the knockdown of GRα in 3D tumor spheroids revealed increased ability of cells to invade the surrounding matrix. In a coculture, encompassing peripheral blood mononuclear cells (PBMC) and MDA-MB-231 cells, and the production of interleukin 6 (IL-6) and interleukin 8 (IL-8) significantly increased compared to a monoculture. Notably, pseudopterosin indicated to block cytokine elevation, representing key players in tumor progression in the coculture. Thus, our results reveal pseudopterosin treatment as a potential novel approach in TNBC therapy.

The Marine Natural Product Pseudopterosin Blocks Cytokine Release of Triple-Negative Breast Cancer and Monocytic Leukemia Cells by Inhibiting NF-κB Signaling

Pseudopterosins are a group of marine diterpene glycosides which possess an array of biological activities including anti-inflammatory effects. However, despite the striking in vivo anti-inflammatory potential, the underlying in vitro molecular mode of action remains elusive. To date, few studies have examined pseudopterosin effects on cancer cells. However, to our knowledge, no studies have explored their ability to block cytokine release in breast cancer cells and the respective bidirectional communication with associated immune cells. The present work demonstrates that pseudopterosins have the ability to block the key inflammatory signaling pathway nuclear factor κB (NF-κB) by inhibiting the phosphorylation of p65 and IκB (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor) in leukemia and in breast cancer cells, respectively. Blockade of NF-κB leads to subsequent reduction of the production of the pro-inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα) and monocyte chemotactic protein 1 (MCP-1). Furthermore, pseudopterosin treatment reduces cytokine expression induced by conditioned media in both cell lines investigated. Interestingly, the presence of pseudopterosins induces a nuclear translocation of the glucocorticoid receptor. When knocking down the glucocorticoid receptor, the natural product loses the ability to block cytokine expression. Thus, we hypothesize that pseudopterosins inhibit NF-κB through activation of the glucocorticoid receptor in triple negative breast cancer.

Nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs

Anticancer therapy has always been a vital challenge for the development of nanomedicine. Repeated single therapeutic agent may lead to undesirable and severe side effects, unbearable toxicity and multidrug resistance due to complex nature of tumor. Nanomedicine-based combination anticancer therapy can synergistically improve antitumor outcomes through multiple-target therapy, decreasing the dose of each therapeutic agent and reducing side effects. There are versatile combinational anticancer strategies such as chemotherapeutic combination, nucleic acid-based co-delivery, intrinsic sensitive and extrinsic stimulus combinational patterns. Based on these combination strategies, various nanocarriers and drug delivery systems were engineered to carry out the efficient co-delivery of combined therapeutic agents for combination anticancer therapy. This review focused on illustrating nanomedicine-based combination anticancer therapy between nucleic acids and small-molecular drugs for synergistically improving anticancer efficacy.

Glucocorticoid receptor-mediated delivery of nano gold-withaferin conjugates for reversal of epithelial-to-mesenchymal transition and tumor regression

AIM

To explore the potential of glucocorticoid receptor-targeted nano-gold formulation as antitumor drug sensitizing agent.

MATERIALS & METHODS

Simultaneous conjugation of gold nanoparticle with thiol-modified dexamethasone, a synthetic glucocorticoid and anticancer drug withaferin A afforded stable gold nanoparticle-modifed dexamethasone-withaferin A nanoconjugate.

RESULTS

This metallic nanoparticle formulation showed glucocorticoid receptor-dependent cancer cell selective cytotoxicity, inhibited growth of aggressive mouse melanoma tumor, reduced mice mortality, while reversing epithelial-to-mesenchymal transition in tumor cells. Same treatment also leads to near-complete downregulation of ABCG2 drug transporter in tumor-associated cells thus attributing it to its drug sensitizing ability.

CONCLUSION

The presently synthesized nanoconjugate holds a great promise to sensitize cancer cells to chemotherapeutics and induce epithelial-to-mesenchymal transition reversal in tumor cells preventing metastasis.