Successful in vivo hyperthermal therapy toward breast cancer by Chinese medicine shikonin-loaded thermosensitive micelle

Novel nano-drug delivery system for natural products and their application

The development of natural products for potential new drugs faces obstacles such as unknown mechanisms, poor solubility, and limited bioavailability, which limit the broadened applicability of natural products. Therefore, there is a need for advanced pharmaceutical formulations of active compounds or natural products. In recent years, novel nano-drug delivery systems (NDDS) for natural products, including nanosuspensions, nanoliposomes, micelle, microemulsions/self-microemulsions, nanocapsules, and solid lipid nanoparticles, have been developed to improve solubility, bioavailability, and tissue distribution as well as for prolonged retention and enhanced permeation. Here, we updated the NDDS delivery systems used for natural products with the potential enhancement in therapeutic efficiency observed with nano-delivery systems.

Preparation, in vitro anti-tumour activity and in vivo pharmacokinetics of RGD-decorated liposomes loaded with shikonin

Shikonin (SHK) has been evidenced to possess effects against various cancer cells. However, poor aqueous solubility and high toxicity restrict its application. In the study, RGD-decorated liposomes loaded with SHK (RGD-Lipo-SHK) were prepared via thin-film hydration method. Characterization and cellular uptake of liposomes was evaluated. Cytotoxicity of blank liposomes and different SHK formulations was measured against breast cancer cells (MDA-MB-231, MCF-7, and MCF-10A). Anti-tumour effects and pharmacokinetic parameters of different SHK formulations were appraised in tumour spheroids and in rat model, respectively. Liposomes displayed a particle size of less than 127 nm with a polydispersity index about 0.21. The encapsulation efficiency was about 91% for SHK, and drug leakage rate of liposomes was less than 6%. RGD-Lipo-SHK showed superior cellular internalization in the αvβ3-positive MDA-MB-231 cells. Blank liposomes had no cytotoxicity to MDA-MB-231 and MCF-7 cells. Howbeit, different SHK formulations obviously inhibited proliferation of MCF-10A cells, especially free SHK. Meanwhile, RGD-Lipo-SHK significantly inhibited growth inhibition of tumour spheroids. The pharmacokinetics study indicated that the peak concentration, area under plasma concentration-time curves, half-life, and mean residence time of RGD-Lipo-SHK distinctly increased compared with those of free SHK. Altogether, these results demonstrated RGD-Lipo-SHK could reduce cytotoxicity, strengthen the antitumor-targeted effect, and prolong circulation time, which provides a foundation for further in vivo experimentations.

Research Progress on Stimulus-Responsive Polymer Nanocarriers for Cancer Treatment

As drug carriers for cancer treatment, stimulus-responsive polymer nanomaterials are a major research focus. These nanocarriers respond to specific stimulus signals (e.g., pH, redox, hypoxia, enzymes, temperature, and light) to precisely control drug release, thereby improving drug uptake rates in cancer cells and reducing drug damage to normal cells. Therefore, we reviewed the research progress in the past 6 years and the mechanisms underpinning single and multiple stimulus-responsive polymer nanocarriers in tumour therapy. The advantages and disadvantages of various stimulus-responsive polymeric nanomaterials are summarised, and the future outlook is provided to provide a scientific and theoretical rationale for further research, development, and utilisation of stimulus-responsive nanocarriers.

Promising Nanomedicines of Shikonin for Cancer Therapy

Malignant tumor, the leading cause of death worldwide, poses a serious threat to human health. For decades, natural product has been proven to be an essential source for novel anticancer drug discovery. Shikonin (SHK), a natural molecule separated from the root of Lithospermum erythrorhizon, shows great potential in anticancer therapy. However, its further clinical application is significantly restricted by poor bioavailability, adverse effects, and non-selective toxicity. With the development of nanotechnology, nano drug delivery systems have emerged as promising strategies to improve bioavailability and enhance the therapeutic efficacy of drugs. To overcome the shortcoming of SHK, various nano drug delivery systems such as liposomes, polymeric micelles, nanoparticles, nanogels, and nanoemulsions, were developed to achieve efficient delivery for enhanced antitumor effects. Herein, this review summarizes the anticancer pharmacological activities and pharmacokinetics of SHK. Additionally, the latest progress of SHK nanomedicines in cancer therapy is outlined, focusing on long circulation, tumor targeting ability, tumor microenvironment responsive drug release, and nanosystem-mediated combination therapy. Finally, the challenges and prospects of SHK nanomedicines in the future clinical application are spotlighted.

Polymeric Micelles for Breast Cancer Therapy: Recent Updates, Clinical Translation and Regulatory Considerations

With the growing burden of cancer, parallel advancements in anticancer nanotechnological solutions have been witnessed. Among the different types of cancers, breast cancer accounts for approximately 25% and leads to 15% of deaths. Nanomedicine and its allied fields of material science have revolutionized the science of medicine in the 21st century. Novel treatments have paved the way for improved drug delivery systems that have better efficacy and reduced adverse effects. A variety of nanoformulations using lipids, polymers, inorganic, and peptide-based nanomedicines with various functionalities are being synthesized. Thus, elaborate knowledge of these intelligent nanomedicines for highly promising drug delivery systems is of prime importance. Polymeric micelles (PMs) are generally easy to prepare with good solubilization properties; hence, they appear to be an attractive alternative over the other nanosystems. Although an overall perspective of PM systems has been presented in recent reviews, a brief discussion has been provided on PMs for breast cancer. This review provides a discussion of the state-of-the-art PMs together with the most recent advances in this field. Furthermore, special emphasis is placed on regulatory guidelines, clinical translation potential, and future aspects of the use of PMs in breast cancer treatment. The recent developments in micelle formulations look promising, with regulatory guidelines that are now more clearly defined; hence, we anticipate early clinical translation in the near future.

Herbal nanomedicines: Recent advancements, challenges, opportunities and regulatory overview

BACKGROUND

Herbal Nano Medicines (HNMs) are nano-sized medicine containing herbal drugs as extracts, enriched fractions or biomarker constituents. HNMs have certain advantages because of their increased bioavailability and reduced toxicities. There are very few literature reports that address the common challenges of herbal nanoformulations, such as selecting the type/class of nanoformulation for an extract or a phytochemical, selection and optimisation of preparation method and physicochemical parameters. Although researchers have shown more interest in this field in the last decade, there is still an urgent need for systematic analysis of HNMs.

PURPOSE

This review aims to provide the recent advancement in various herbal nanomedicines like polymeric herbal nanoparticles, solid lipid nanoparticles, phytosomes, nano-micelles, self-nano emulsifying drug delivery system, nanofibers, liposomes, dendrimers, ethosomes, nanoemulsion, nanosuspension, and carbon nanotube; their evaluation parameters, challenges, and opportunities. Additionally, regulatory aspects and future perspectives of herbal nanomedicines are also being covered to some extent.

METHODS

The scientific data provided in this review article are retrieved by a thorough analysis of numerous research and review articles, textbooks, and patents searched using the electronic search tools like Sci-Finder, ScienceDirect, PubMed, Elsevier, Google Scholar, ACS, Medline Plus and Web of Science.

RESULTS

In this review, the authors suggested the suitability of nanoformulation for a particular type of extracts or enriched fraction of phytoconstituents based on their solubility and permeability profile (similar to the BCS class of drugs). This review focuses on different strategies for optimising preparation methods for various HNMs to ensure reproducibility in context with all the physicochemical parameters like particle size, surface area, zeta potential, polydispersity index, entrapment efficiency, drug loading, and drug release, along with the consistent therapeutic index.

CONCLUSION

A combination of herbal medicine with nanotechnology can be an essential tool for the advancement of herbal medicine research with enhanced bioavailability and fewer toxicities. Despite the challenges related to traditional medicine's safe and effective use, there is huge scope for nanotechnology-based herbal medicines. Overall, it is well stabilized that herbal nanomedicines are safer, have higher bioavailability, and have enhanced therapeutic value than conventional herbal and synthetic drugs.

Fe(III)-Shikonin Supramolecular Nanomedicine for Combined Therapy of Tumor via Ferroptosis and Necroptosis

Most of the antitumor chemotherapeutic drugs execute the therapeutic performance upon eliciting tumor cell apoptosis, which may cause chemoresistance of tumors. Design of novel drugs to eradicate apoptosis-resistant tumors via non-apoptotic cell death pathways is promising for improving the long-term chemotherapeutic efficacy. Herein, a Fe(III)-Shikonin metal-polyphenol-coordinated supramolecular nanomedicine for combined therapy of tumor via ferroptosis and necroptosis is designed. The construction of the nanomedicine based on the coordinated self-assembly between Fe³⁺ and Shikonin not only overcomes the shortcomings of Shikonin including its low bioavailability and high toxicity toward normal tissues, but also integrates the theranostics functions of Fe ions. Under the exposure of the high concentration of glutathione (GSH) in tumor cells, the as-prepared nanomedicine will disassemble into Fe²⁺ and Shikonin, followed by stimulating the tumor cell death through ferroptosis and necroptosis. In addition, benefiting from the stealth effect of polyethylene glycol (PEG) and the targeting ability of cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) to α_v β₃ -integrin, NH₂ -PEG-cRGD-modified nanomedicine exhibits a GSH-responsive therapy toward 4T1 tumor in vivo and self-enhanced longitudinal relaxation (T₁ )-weighted imaging property. Since the self-assembly of natural Shikonin and human body-necessary Fe element is facile and feasible, the work may provide a promising supramolecular nanomedicine for next-generation chemotherapeutic applications.

Shikonin, a naphthalene ingredient: Therapeutic actions, pharmacokinetics, toxicology, clinical trials and pharmaceutical researches

BACKGROUND

Shikonin is one of the major phytochemical components of Lithospermum erythrorhizon (Purple Cromwell), which is a type of medicinal herb broadly utilized in traditional Chinese medicine. It is well established that shikonin possesses remarkable therapeutic actions on various diseases, with the underlying mechanisms, pharmacokinetics and toxicological effects elusive. Also, the clinical trial and pharmaceutical study of shikonin remain to be comprehensively delineated.

PURPOSE

The present review aimed to systematically summarize the updated knowledge regarding the therapeutic actions, pharmacokinetics, toxicological effects, clinical trial and pharmaceutical study of shikonin.

METHODS

The information contained in this review article were retrieved from some authoritative databases including Web of Science, PubMed, Google scholar, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database and so on, till August 2021.

RESULTS

Shikonin exerts multiple therapeutic efficacies, such as anti-inflammation, anti-cancer, cardiovascular protection, anti-microbiomes, analgesia, anti-obesity, brain protection, and so on, mainly by regulating the NF-κB, PI3K/Akt/MAPKs, Akt/mTOR, TGF-β, GSK3β, TLR4/Akt signaling pathways, NLRP3 inflammasome, reactive oxygen stress, Bax/Bcl-2, etc. In terms of pharmacokinetics, shikonin has an unfavorable oral bioavailability, 64.6% of the binding rate of plasma protein, and enhances some metabolic enzymes, particularly including cytochrome P450. In regard to the toxicological effects, shikonin may potentially cause nephrotoxicity and skin allergy. The above pharmacodynamics and pharmacokinetics of shikonin have been validated by few clinical trials. In addition, pharmaceutical innovation of shikonin with novel drug delivery system such as nanoparticles, liposomes, microemulsions, nanogel, cyclodextrin complexes, micelles and polymers are beneficial to the development of shikonin-based drugs.

CONCLUSIONS

Shikonin is a promising phytochemical for drug candidates. Extensive and intensive explorations on shikonin are warranted to expedite the utilization of shikonin-based drugs in the clinical setting.

The Efficacy of Vitamin K, A Member Of Naphthoquinones in the Treatment of Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Redox dysregulation originating from metabolic alterations in cancer cells contributes to their proliferation, invasion, and resistance to therapy. Conversely, these features represent a specific vulnerability of malignant cells that can be selectively targeted by redox chemotherapeutics. Amongst them, Vitamin K (VitK) carries the potential against cancer stem cells, in addition to the rest of tumor mass.

OBJECTIVES

To assess the possible benefits and safety of VitK for cancer treatment using a systematic review and meta-analysis with a mixed-methods approach.

METHODS

We performed a systematic search on several electronic databases for studies comparing VitK treatment with and without combination to the control groups. For quantitative studies, fully or partially reported clinical outcomes such as recurrence rates, survival, overall response and adverse reactions were assessed. For qualitative studies, a narrative synthesis was accomplished.

RESULTS

Our analysis suggested that the clinical outcome of efficacy, the pooled hazard ratio for progression-free survival, and the pooled relative risk for overall survival, and overall response were significantly higher in the VitK therapy group compared to the placebo group (p<0.05). We did not observe any significant difference in the occurrence of adverse events between groups. Among qualitative studies, VitK treatment targeting myelodysplastic syndrome and advanced solid tumors resulted in 24.1% and 10% of clinical response, respectively.

CONCLUSION

VitK not only exerts antitumor effects against a wide range of tumor types, but it also has excellent synergism with other therapeutic agents.

The combination of nanotechnology and traditional Chinese medicine (TCM) inspires the modernization of TCM: review on nanotechnology in TCM-based drug delivery systems

Fast development of combination of nanotechnology with traditional Chinese medicine (TCM) broadens the field of application of TCM. Besides, it increases the research ideas and contributes to TCM modernization. As expected, TCM will be developed into the nanodrug delivery system by nanotechnology with careful design, which will enhance the medicinal value of TCM to cure and prevent disease based on benefits brought by nanometer scale. Here, formulations, relevant preparations methods, and characteristics of nano-TCM were introduced. In addition, the main excellent performances of nano-TCM were clearly elaborated. What is more, the review was intended to address the studies committed to application of nanotechnology in TCM over the years, including development of Chinese medicine active ingredients, complete TCM, and Chinese herbal compounds based on nanotechnology. Finally, this review discussed the safety of nano-TCM and presented future development trends in the way to realize the modernization of TCM. Overall, using the emerging nanotechnology in TCM is promising to promote progress of TCM in international platform. Recent researches on modernization of traditional Chinese medicine (TCM) urged by nanotechnology are introduced, and formulations, advantages, and applications of nano-TCM are reviewed to provide strong proofs.

Innovative Delivery Systems Loaded with Plant Bioactive Ingredients: Formulation Approaches and Applications

Plants constitute a rich source of diverse classes of valuable phytochemicals (e.g., phenolic acids, flavonoids, carotenoids, alkaloids) with proven biological activity (e.g., antioxidant, anti-inflammatory, antimicrobial, etc.). However, factors such as low stability, poor solubility and bioavailability limit their food, cosmetics and pharmaceutical applications. In this regard, a wide range of delivery systems have been developed to increase the stability of plant-derived bioactive compounds upon processing, storage or under gastrointestinal digestion conditions, to enhance their solubility, to mask undesirable flavors as well as to efficiently deliver them to the target tissues where they can exert their biological activity and promote human health. In the present review, the latest advances regarding the design of innovative delivery systems for pure plant bioactive compounds, extracts or essential oils, in order to overcome the above-mentioned challenges, are presented. Moreover, a broad spectrum of applications along with future trends are critically discussed.

Design of dual targeting immunomicelles loaded with bufalin and study of their anti-tumor effect on liver cancer

OBJECTIVE

Bufalin is an effective drug for the treatment of liver cancer. But its high toxicity, poor water-solubility, fast metabolism and short elimination half-life limit its use in tumor treatment. How to make the drug accumulate in the tumor and reduce side effects while maintaining its efficacy are urgent problems to be solved. The goal of this study is to solve these problems.

METHODS

A copolymer with tunable poly-N-isopropylacrylamide and polylactic acid was designed and synthesized. The corresponding dual targeting immunomicelles (DTIs) loaded with bufalin (DTIs-BF) were synthesized by copolymer self-assembly in an aqueous solution. The size and structure of DTIs-BF were determined by ZetaSizer Nano-ZS and transmission electron microscopy. Then, its temperature sensitivity, serum stability, critical micelle concentration (CMC), entrapment efficiency (EE), drug release and non-cytotoxicity of blank block copolymer micelles (BCMs) were evaluated. Next, the effects of DTIs-BF on cellular uptake, cytotoxicity, and tumor cell inhibition were evaluated. Finally, the accumulation of DTIs-fluorescein isothiocyanate (FITC) and the in vivo anti-tumor effect were observed using an interactive video information system.

RESULTS

DTIs-BF had a small size, spherical shape, good temperature sensitivity, high serum stability, low CMC, high EE, and slow drug release. The blank BCMs had very low cytotoxicity. Compared with free bufalin, the in vitro cellular internalization and cytotoxicity of DTIs-BF against SMMC-7721 cells were significantly enhanced, and the effects were obviously better at 40 °C than 37 °C. In addition, the therapeutic effect on SMMC-7721 cells was further enhanced by the programmed cell death specifically caused by bufalin. When DTIs-FITC were injected intravenously in BALB/c nude mice bearing liver cancer, the accumulation of FITC was significantly increased in tumors.

CONCLUSION

DTIs-BF is a potentially effective nano-formulation and has broad prospects in the clinical treatment of liver cancer.

A systematic review and meta-analysis of traditional Chinese medicine with chemotherapy in breast cancer

Background

With the continuous progression of a new generation of adjuvant chemotherapy, the survival time of breast cancer patients has also been significantly improved. Chemotherapy alone will cause a series of side effects, which will seriously affect the quality of life of breast cancer patients. Chinese medicine combined with neoadjuvant chemotherapy has a unique advantage in the treatment of breast cancer.

Methods

English databases were searched using combinations of the following search terms: "traditional Chinese medicine", "neoadjuvant hemotherapy", "breast cancer", and "tumor of breast". Publications in which traditional Chinese medicine (TCM) combined with neoadjuvant therapy was the experimental group and chemotherapy alone was the control group were screened.

Results

A total of 12 publications were included in the meta-analysis. The efficiency of the performance status score was used to test for heterogeneity, Chi²=2.95, df=5, P=0.71>0.1, I²=0%, Z=3.36, odds ratio (OR) =2.61, and 95% confidence interval (CI), 1.49-4.58. The results of the heterogeneity test of the effective rate of the objective curative effect were as follows: Chi²=1.04, df=7, P=0.99>0.1, I²=0%<50%, Z=2.42, OR =2.00, and 95% CI, 1.14-3.49. The results for the heterogeneity test of the TCM syndrome score were as follows: I²=83%, P<0.00001, mean difference (MD) =8.84, 95% CI, 6.43-11.25, P<0.05. The results for the heterogeneity test of the incidence of adverse reactions in the digestive system after chemotherapy were as follows: Chi²=1.15, df=8, P=1.00>0.1, I²=0%<50%, Z=1.68, OR =0.04, 95% CI, -0.01 to 0.09.

Discussion

The meta-analysis confirmed that using TCM combined with neoadjuvant chemotherapy to treat breast cancer has obvious advantages over chemotherapy alone in terms of the objective curative effect, the performance status score effective rate, the TCM syndrome score change, and the incidence of gastrointestinal adverse reactions after chemotherapy.

Shikonin Inhibits Cholangiocarcinoma Cell Line QBC939 by Regulating Apoptosis, Proliferation, and Invasion

This study was designed to clarify whether Shikonin causes proliferation, apoptosis, and invasion in cholangiocarcinoma cells and to investigate the mechanism of action. QBC939 cells were cultured with different doses of Shikonin, and then 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium assay was used to detect cell viability. Apoptosis of cells was detected using flow cytometry with Annexin V/propidium iodide (PI) assay after being stained with Hoechst 33242. The role of Shikonin on the invasive and metastasis ability was detected using Transwell invasion assay. Real-time polymerase chain reaction and Western blotting were used to detect the expression of caspase-3, caspase-8, epidermal growth factor receptor (EGFR), and matrix metalloproteinase (MMP)-9. Shikonin inhibited proliferation and invasive ability of QBC939 cells in a dose-dependent manner; at the same time, apoptosis of cells was also observed in a concentration-dependent fashion. Moreover, Annexin V/PI assay and Transwell invasion assay results indicated that Shikonin induced apoptosis and invasion inhibitory probably due to upregulation of caspase-3 and caspase-8 expression and downregulation of MMP-9 and EGFR expression in a concentration-dependent fashion. Shikonin could enhance apoptosis and inhibit proliferation and invasion of QBC939 cells; such biological behaviors mainly occurred via upregulating the expression of caspase-3 and caspase-8 and downregulating the expression of MMP-9 and EGFR.

Design of DOX-GNRs-PNIPAM@PEG-PLA Micelle With Temperature and Light Dual-Function for Potent Melanoma Therapy

Objective: The aim of this study was to construct light and temperature dual-sensitive micellar carriers loaded with doxorubicin (DOX) and gold nanorods (DOX-GNRs-PNIPAM@PEG-PLA, DAPP) for melanoma therapy. Methods: The DAPP self-assembled using fine-tuned physicochemical properties in water. The DAPP structure, temperature- and photo-sensitivity, drug-release, in-vitro serum stability, and cytotoxicity against melanoma B16F10 cells were evaluated in detail. The corresponding in-vitro and in-vivo therapeutic mechanisms were then evaluated using a B16F10-melanoma bearing BALB/c nude mouse model (B16F10). Results: The light and temperature sensitive micellar drug-delivery system assembled from block copolymer and gold nanorods exhibited a narrow particle size and size distribution, good biocompatibility, well-designed photo-temperature conversion, controlled drug release, and high serum stability. Compared with the free DOX- and PBS-treated groups, the cell endocytosis-mediated cytotoxicity and intra-tumor accumulation of DAPP was markedly enhanced by the NIR-light exposure and induced potent in-vivo tumor inhibitory activity. Conclusion: The design of DAPP, a dual-functional micellar drug-delivery system with temperature- and light-sensitive properties, offers a new strategy for skin-cancer therapy with a potent therapeutic index.

Stimuli-responsive Drug Delivery Nanocarriers in the Treatment of Breast Cancer

Stimuli-responsive drug-delivery nanocarriers (DDNs) have been increasingly reported in the literature as an alternative for breast cancer therapy. Stimuli-responsive DDNs are developed with materials that present a drastic change in response to intrinsic/chemical stimuli (pH, redox and enzyme) and extrinsic/physical stimuli (ultrasound, Near-infrared (NIR) light, magnetic field and electric current). In addition, they can be developed using different strategies, such as functionalization with signaling molecules, leading to several advantages, such as (a) improved pharmaceutical properties of liposoluble drugs, (b) selectivity with the tumor tissue decreasing systemic toxic effects, (c) controlled release upon different stimuli, which are all fundamental to improving the therapeutic effectiveness of breast cancer treatment. Therefore, this review summarizes the use of stimuli-responsive DDNs in the treatment of breast cancer. We have divided the discussions into intrinsic and extrinsic stimuli and have separately detailed them regarding their definitions and applications. Finally, we aim to address the ability of these stimuli-responsive DDNs to control the drug release in vitro and the influence on breast cancer therapy, evaluated in vivo in breast cancer models.

Novel Drug Delivery Systems for Loading of Natural Plant Extracts and Their Biomedical Applications

Many types of research have distinctly addressed the efficacy of natural plant metabolites used for human consumption both in cell culture and preclinical animal model systems. However, these in vitro and in vivo effects have not been able to be translated for clinical use because of several factors such as inefficient systemic delivery and bioavailability of promising agents that significantly contribute to this disconnection. Over the past decades, extraordinary advances have been made successfully on the development of novel drug delivery systems for encapsulation of plant active metabolites including organic, inorganic and hybrid nanoparticles. The advanced formulas are confirmed to have extraordinary benefits over conventional and previously used systems in the manner of solubility, bioavailability, toxicity, pharmacological activity, stability, distribution, sustained delivery, and both physical and chemical degradation. The current review highlights the development of novel nanocarrier for plant active compounds, their method of preparation, type of active ingredients, and their biomedical applications.

Shikonin derivatives for cancer prevention and therapy

Phytochemicals gained considerable interest during the past years as source to develop new treatment options for chemoprevention and cancer therapy. Motivated by the fact that a majority of established anticancer drugs are derived in one way or another from natural resources, we focused on shikonin, a naphthoquinone with high potentials to be further developed as preventive or therapeutic drug to fight cancer. Shikonin is the major chemical component of Lithospermum erythrorhizon (Purple Cromwell) roots. Traditionally, the root extract has been applied to cure dermatitis, burns, and wounds. Over the past three decades, the anti-inflammatory and anticancer effects of root extracts, isolated shikonin as well as semi-synthetic and synthetic derivatives and nanoformulations have been described. In vitro and in vivo experiments were conducted to understand the effect of shikonin at cellular and molecular levels. Preliminary clinical trials indicate the potential of shikonin for translation into clinical oncology. Shikonin exerts additive and synergistic interactions in combination with established chemotherapeutics, immunotherapeutic approaches, radiotherapy and other treatment modalities, which further underscores the potential of this phytochemical to be integrated into standard treatment regimens.

Anticancer Efficacy of Targeted Shikonin Liposomes Modified with RGD in Breast Cancer Cells

Shikonin (SHK) has been proven to have a good anti-tumor effect. However, poor water solubility and low bioavailability limit its wide application in clinical practice. In this study, to overcome these drawbacks, RGD-modified shikonin-loaded liposomes (RGD-SSLs-SHK) were successfully prepared. It exhibited excellent physicochemical characteristics including particle size, zeta potential, encapsulation efficiency, and delayed release time. Meanwhile, the targeting activity of the RGD-modified liposomes was demonstrated by flow cytometry and confocal microscopy in the α_vβ₃-positive MDA-MB-231 cells. Besides exhibiting greater cytotoxicity in vitro, compared with non-targeted shikonin-loaded liposomes (SSLs-SHK), RGD-SSLs-SHK could also evidently induce apoptosis by decreasing the expression of Bcl-2 and increasing the expression of Bax. It could also inhibit cell proliferation, migration, invasion, and adhesion by reducing the expression of MMP-9 and the level of NF-κB p65, but did not affect the expression of MMP-2 in the MDA-MB-231 cells. Therefore, these findings indicated that the strategy to use RGD-modified liposomes as carriers for targeted delivery of shikonin is a very promising approach to achieve breast cancer targeted therapy.