Depletion of gut microbiota improves the therapeutic efficacy of cancer nanomedicine.

Rationale: Gut microbiota plays a crucial role in cancer development and treatment. Studies show that although the gut microbiota is able to promote tumor growth, its presence also improves the efficacy of cancer treatment such as immunotherapy. To date, understanding of the potential impact of the gut microbiota on other treatment modalities such as cancer nanomedicine is still limited. In this study, we aimed to establish the relationship between gut microbiota and cancer nanomedicine, which can potentially open a new path in cancer treatment that combines gut microbiota modulation along with nanotherapeutics. Methods: Mice bearing 4T1 triple-negative breast cancer cells were subjected to gut microbiota modulation by antibiotics (ABX) treatment in the drinking water. Mice given normal water was used for control. The effects of ABX treatment towards gut bacteria was studied by RT-qPCR and 16S next generation sequencing of fecal samples. The mice were then subjected to liposomal doxorubicin (LipoDox) treatment and the amount of nanotherapeutics that accumulated in the tumors was quantified. For therapeutic efficacy, the mice were subjected to ABX treatment and given three injections of LipoDox or saline, while the tumor growth was monitored throughout. Results: Analysis of fecal bacterial content showed that ABX treatment resulted in depletion of gut microbiota. Quantification of LipoDox content revealed significantly increased accumulation in ABX tumor compared to control. Compared to LipoDox treatment alone, we found that combined gut microbiota depletion and LipoDox treatment resulted in augmented long-term anti-tumor efficacy and significantly improved median survival compared to LipoDox only (control vs ABX = 58.5 vs 74 days, p = 0.0002, n = 10 for both groups), with two mice surviving until the end of the experimental end point without experiencing relapse. We also identified the increase in vascular permeability of ABX-treated tumors correlated to for improved therapeutic efficacy and outcome. Conclusion: We showed that gut microbiota depletion led to enhanced tumor vascular permeability, which allowed a larger amount of LipoDox nanoparticles to accumulate in the tumor, leading to better long-term effects. Our results suggest that gut microbiota modulation may be exploited in combination with available nanomedicine-based therapeutics to improve cancer diagnosis, therapeutic efficacy and outcome.

Advances in Biomimetic Nanoparticles for Targeted Cancer Therapy and Diagnosis.

Biomimetic nanoparticles have recently emerged as a novel drug delivery platform to improve drug biocompatibility and specificity at the desired disease site, especially the tumour microenvironment. Conventional nanoparticles often encounter rapid clearance by the immune system and have poor drug-targeting effects. The rapid development of nanotechnology provides an opportunity to integrate different types of biomaterials onto the surface of nanoparticles, which enables them to mimic the natural biological features and functions of the cells. This mimicry strategy favours the escape of biomimetic nanoparticles from clearance by the immune system and reduces potential toxic side effects. Despite the rapid development in this field, not much has progressed to the clinical stage. Thus, there is an urgent need to develop biomimetic-based nanomedicine to produce a highly specific and effective drug delivery system, especially for malignant tumours, which can be used for clinical purposes. Here, the recent developments for various types of biomimetic nanoparticles are discussed, along with their applications for cancer imaging and treatments.

Immune cell shuttle for precise delivery of nanotherapeutics for heart disease and cancer.

The delivery of therapeutics through the circulatory system is one of the least arduous and less invasive interventions; however, this approach is hampered by low vascular density or permeability. In this study, by exploiting the ability of monocytes to actively penetrate into diseased sites, we designed aptamer-based lipid nanovectors that actively bind onto the surface of monocytes and are released upon reaching the diseased sites. Our method was thoroughly assessed through treating two of the top causes of death in the world, cardiac ischemia-reperfusion injury and pancreatic ductal adenocarcinoma with or without liver metastasis, and showed a significant increase in survival and healing with no toxicity to the liver and kidneys in either case, indicating the success and ubiquity of our platform. We believe that this system provides a new therapeutic method, which can potentially be adapted to treat a myriad of diseases that involve monocyte recruitment in their pathophysiology.

Effect of fetal bovine serum on erythropoietin receptor expression and viability of breast cancer cells.

Erythropoietin receptors (EPORs) are present not only in erythrocyte precursors but also in non-hematopoietic cells including cancer cells. In this study, we determined the effect of fetal bovine serum (FBS) in culture medium on the EPOR expression and viability of the estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 breast cancer cells. Using flow cytometry, we showed that the inclusion of 10% FBS in the medium increased the EPOR expressions and viabilities of MDA-MB-231 and MCF-7 cells. The MDA-MB-231 showed greater EPOR expression than MCF-7 cells, suggesting that the presence of ERs on cells is associated with poor expression of EPOR. Culture medium containing 10% FBS also caused increased number of breast cancer cells entering the synthesis phase of the cell cycle. The study also showed that rHuEPO treatment did not affect viability of breast cancer cells. In conclusion, it was shown that the inclusion of FBS in culture medium increased expression of EPOR in breast cancer cells and rHuEPO treatment had no effect on the proliferation of these cancer cells.

Enhanced anti-mammary gland cancer activities of tamoxifen-loaded erythropoietin-coated drug delivery system.

Nanomedicine is an emerging area in the medical field, particularly in the treatment of cancers. Nanostructured lipid carrier (NLC) was shown to be a good nanoparticulated carrier for the delivery of tamoxifen (TAM). In this study, the tamoxifen-loaded erythropoietin-coated nanostructured lipid carriers (EPO-TAMNLC) were developed to enhance the anti-cancer properties and targetability of TAM, using EPO as the homing ligand for EPO receptors (EpoRs) on breast cancer tissue cells. Tamoxifen-loaded NLC (TAMNLC) was used for comparison. The LA7 cells and LA7 cell-induced rat mammary gland tumor were used as models in the study. Immunocytochemistry staining showed that LA7 cells express estrogen receptors (ERs) and EpoRs. EPO-TAMNLC and TAMNLC significantly (p<0.05) inhibited proliferation of LA7 in dose- and time-dependent manner. EPO-TAMNLC induced apoptosis and G0/G1 cell cycle arrest of LA7 cells. Both drug delivery systems showed anti-mammary gland tumor properties. At an intravenous dose of 5 mg kg-1 body weight, EPO-TAMNLC and TAMNLC were not toxic to rats, suggesting that both are safe therapeutic compounds. In conclusion, EPO-TAMNLC is not only a unique drug delivery system because of the dual drug-loading feature, but also potentially highly specific in the targeting of breast cancer tissues positive for ERs and EpoRs. The incorporation of TAM into NLC with and without EPO coat had significantly (p<0.05) improved specificity and safety of the drug carriers in the treatment of mammary gland tumors.

Induction of cell cycle arrest and apoptosis by copper complex Cu(SBCM)2 towards oestrogen-receptor positive MCF-7 breast cancer cells.

Copper complexes have the potential to be developed as targeted therapy for cancer because cancer cells take up larger amounts of copper than normal cells. Copper complex Cu(SBCM)2 has been reported to induce cell cycle arrest and apoptosis towards triple-negative breast cancer cells. Nevertheless, its effect towards other breast cancer subtypes has not been explored. Therefore, the present study was conducted to investigate the effect of Cu(SBCM)2 towards oestrogen-receptor positive MCF-7 breast cancer cells. Growth inhibition of Cu(SBCM)2 towards MCF-7 and human non-cancerous MCF-10A breast cells was determined by MTT assay. Morphological changes of Cu(SBCM)2-treated-MCF-7 cells were observed under an inverted microscope. Annexin V/PI apoptosis assay and cell cycle analysis were evaluated by flow cytometry. The expression of wild-type p53 protein was evaluated by Western blot analysis. The intracellular ROS levels of MCF-7 treated with Cu(SBCM)2 were detected using DCFH-DA under a fluorescence microscope. The cells were then co-treated with Cu(SBCM)2 and antioxidants to evaluate the involvement of ROS in the cytotoxicity of Cu(SBCM)2. Docking studies of Cu(SBCM)2 with DNA, DNA topoisomerase I, and human ribonucleotide reductase were also performed. The growth of MCF-7 cells was inhibited by Cu(SBCM)2 in a dose-dependent manner with less toxicity towards MCF-10A cells. It was found that Cu(SBCM)2 induced G2/M cell cycle arrest and apoptosis in MCF-7 cells, possibly via a p53 pathway. Induction of intracellular ROS was not detected in MCF-7 cells. Interestingly, antioxidants enhance the cytotoxicity of Cu(SBCM)2 towards MCF-7 cells. DNA topoisomerase I may be the most likely target that accounts for the cytotoxicity of Cu(SBCM)2.

Zerumbone-Loaded Nanostructured Lipid Carrier Induces Apoptosis of Canine Mammary Adenocarcinoma Cells.

Canine mammary gland tumor (CMT) is the most common tumor in intact female dog. Zerumbone (ZER) has promising anticancer properties, but plagued with poor water solubility, poor absorption, bioavailability, and delivery to target tissues. To solubilize, ZER was loaded into nanostructured lipid carrier (NLC) to produce ZER-loaded NLC (ZER-NLC). The objectives of this study were to determine the antiproliferative effect and the mode of cell death induced by ZER-NLC and ZER on a canine mammary gland tumor (CMT) adenocarcinoma primary cell line. There was no significant difference (p>0.05) between ZER-NLC and ZER treatments in the inhibition of CMT cell proliferation; thus, the loading of ZER into NLC did not compromise the cytotoxic effect of ZER. Microscopically, ZER-NLC- and ZER-treated CMT cells showed apoptotic cell morphology. ZER-NLC and ZER treatments significantly downregulated the antiapoptotic Bcl-2 and upregulated the proapoptotic Bax gene expressions in CMT cells. Both ZER-NLC and ZER-treated CMT cells showed significant (p<0.0001) increases in caspase-8, -9, and -3/7 protein activities. In conclusion, ZER-NLC induced CMT cell death via regulation of Bcl-2 and Bax gene expressions and caspase activations, indicating the involvement of both the intrinsic and extrinsic pathways of apoptosis. This study provided evidences for the potential of ZER-NLC as an anticanine mammary gland adenocarcinoma chemotherapy.

Copper complex derived from S-benzyldithiocarbazate and 3-acetylcoumarin induced apoptosis in breast cancer cell.

Copper complexes have been widely studied for the anti-tumour application as cancer cells are reported to take up greater amounts of copper than normal cells. Preliminary study revealed that the newly synthesised copper complex [Cu(SBCM)2] displayed marked anti-proliferative towards triple-negative MDA-MB-231 breast cancer cells. Therefore, Cu(SBCM)2 has great potential to be developed as an agent for the management of breast cancer. The present study was carried out to investigate the mode of cell death induced by Cu(SBCM)2 towards MDA-MB-231 breast cancer cells. The inhibitory and morphological changes of MDA-MB-231 cells treated with Cu(SBCM)2 was determined by using MTT assay and inverted light microscope, respectively. The safety profile of Cu(SBCM)2 was also evaluated towards human dermal fibroblast (HDF) normal cells. Confirmation of apoptosis and cell cycle arrest were determined by flow cytometry analysis. The expression of p53, Bax, Bcl-2 and MMP2 protein were detected with western blot analysis. Cu(SBCM)2 significantly inhibited the growth of MDA-MB-231 cells in a dose-dependent manner with GI50 18.7 ± 3.06 µM. Indeed, Cu(SBCM)2 was less toxic towards HDF normal cells with GI50 31.8 ± 4.0 µM. Morphological study revealed that Cu(SBCM)2-treated MDA-MB-231 cells experienced cellular shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies, suggesting that Cu(SBCM)2 induced apoptosis in the cells, which was confirmed by Annexin-V/PI flow cytometry analysis. It was also found that Cu(SBCM)2 induced G2/M phase cell cycle arrest towards MDA-MB-231 cells. The induction of apoptosis and cell cycle arrest in the present study is possibly due to the down-regulation of the mutant p53 and MMP2 protein. In conclusion, Cu(SBCM)2 can be developed as a targeted therapy for the treatment of triple-negative breast cancer.

Development of erythropoietin receptor-targeted drug delivery system against breast cancer using tamoxifen-loaded nanostructured lipid carriers.

Tamoxifen (TAM) has been used in the treatment of breast cancers and is supplemented with erythropoietin (EPO) to alleviate the cancer-related anemia. The purported deleterious effects caused by the use of EPO with chemotherapeutic agents in the treatment of cancer-related anemia vary across studies and remain controversial. The use of nanoparticles as a drug delivery system has the potential to improve the specificity of anticancer drugs. In this study, we simultaneously incorporated two pharmacological active ingredients in one nanocarrier to develop EPO-conjugated TAM-loaded lipid nanoparticles (EPO-TAMNLC), a targeted delivery system, to enhance the cytotoxic activity while reducing the side effects of the ingredients. The effect of temperature in modulating the thermodynamic parameters associated with the binding of EPO and TAMNLC was assessed using isothermal titration calorimetry, while the unfolding of EPO structure was determined using fluorescence-quenching approach. The association efficiency of EPO and TAMNLC was 55.43%. Unlike binding of albumin to TAMNLC, the binding of EPO to TAMNLC occurred through endothermic and entropy-driven reaction. The EPO-TAMNLC formulation was stable because of the hydrophobic interaction and the high free energy, suggesting the spontaneity of the interactions between EPO and TAMNLC. The EPO-TAMNLC enhanced the in vitro cytotoxicity of TAM to MCF-7 cells. The EPO surface-functionalized TAMNLC could sequentially deliver EPO and TAM as well as improving site-specific delivery of these therapeutic compounds.