Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 ± 0.011) with a mean particle size of 27.3 ± 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 ± 1.02%, and drug loading of 12.95 ± 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t(1/2) and AUC of curcumin in vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesis in vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cells in vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg(-1) curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

cTo design and discover new antimicrobial peptides (AMPs) with high levels of antimicrobial activity, a number of machinelearning methods and prediction methods have been developed. Here, we present a new prediction method that can identify novel AMPs that are highly similar in sequence to known peptides but offer improved antimicrobial activity along with lower host cytotoxicity. Using previously generated AMP amino acid substitution data, we developed an amino acid activity contribution matrix that contained an activity contribution value for each amino acid in each position of the model peptide. A series of AMPs were designed with this method. After evaluating the antimicrobial activities of these novel AMPs against both Gram-positive and Gram-negative bacterial strains, DP7 was chosen for further analysis. Compared to the parent peptide HH2, this novel AMP showed broad-spectrum, improved antimicrobial activity, and in a cytotoxicity assay it showed lower toxicity against human cells. The in vivo antimicrobial activity of DP7 was tested in a Staphylococcus aureus infection murine model. When inoculated and treated via intraperitoneal injection, DP7 reduced the bacterial load in the peritoneal lavage solution. Electron microscope imaging and the results indicated disruption of the S. aureus outer membrane by DP7. Our new prediction method can therefore be employed to identify AMPs possessing minor amino acid differences with improved antimicrobial activities, potentially increasing the therapeutic agents available to combat multidrug-resistant infections.A ntimicrobial peptides (AMPs) are produced by multicellular organisms to defend against microbial infections. Along with potent antimicrobial activity, many AMPs also have the ability to enhance immunity by functioning as immunomodulators (1-3). AMPs therefore have excellent therapeutic potential, especially in light of increased drug resistance to many conventional antibiotic therapies. A number of naturally occurring peptides and synthetic derivatives have been developed or are currently in development (2, 4-6). Although AMPs vary in length, amino acid composition, and structure, they share some similarities, such as electrical charge and amphipathicity (3, 7). To determine the characteristics that are important in antimicrobial activity, bioinformatic tools and prediction methods have been developed (8), all based to some extent on the sequence similarities between peptides (9-11).To optimize the antimicrobial activity of identified AMPs and to predict novel peptide sequences, we present a machine-learning method based on the concept of an antimicrobial activity contribution score for each amino acid. Here, we consider that each amino acid in a peptide sequence possesses a different level of importance for the biological activity of that peptide, and this is represented by an assigned score. By calculation of each amino acid's contribution score, we can predict the antimicrobial activity of an AMP.To verify our results, we tested some of our designed AMPs ...

Breast cancer remains a major health problem worldwide. While chemotherapy represents an important therapeutic modality against breast cancer, limitations in the clinical use of chemotherapy remain formidable because of chemoresistance. The HER2/PI-3K/Akt pathway has been demonstrated to play a causal role in conferring a broad chemoresistance in breast cancer cells and thus justified to be a target for enhancing the effects of anti-breast cancer chemotherapies, such as adriamycin (ADR). Agents that can either enhance the effects of chemotherapeutics or overcome chemoresistance are urgently needed for the treatment of breast cancer. In this context, SZ-685C, an agent that has been previously shown, as such, to suppress Akt signaling, is expected to increase the efficacy of chemotherapy. Our current study investigated whether SZ-685C can override chemoresistance through inhibiting Akt signaling in human breast cancer cells. ADR-resistant cells derived from human breast cancer cell lines MCF-7, MCF-7/ADR and MCF-7/Akt, were used as models to test the effects of SZ-685C. We found that SZ-685C suppressed the Akt pathway and induced apoptosis in MCF-7/ADR and MCF-7/Akt cells that are resistant to ADR treatment, leading to antitumor effects both in vitro and in vivo. Our data suggest that use of SZ-685C might represent a potentially promising approach to the treatment of ADR-resistant breast cancer.

Gramicidin S (GS), one of the oldest commercially used peptide antibiotics, is known for its robust antibacterial activity against both Gram-positive and Gram-negative bacterial strains. Although it was discovered well over 70 years ago, its clinical potential was limited to topical applications because of its high hemolytic activity. To overcome this side effect, significant efforts have been invested in the chase for GS analogues with high therapeutic index (e.g., high antimicrobial activity and low hemolytic activity) in the past decades. In this Perspective, the structural properties and biological profiles (including the recently discovered activities) of representative GS analogues designed by different approaches are described and analyzed. We also present how the general structure–activity relationships were established and how they could help in the design of more efficient GS analogues.

BackgroundNatural killer (NK) cells can kill tumor cells in a non-MHC-restricted manner. However, cancer cells frequently escape from the attack of NK cells by multiple ways. In this study, we investigated the effect of gefitinib on the interaction between NK cells and lung cancer cells.Methods51Cr release assay, CD107a assay, and IFN-γ secretion assay were performed to detect the sensitivity of lung cancer cell lines A549 and H1975 to NK cells cytotoxicity in the presence of gefitinib. Human NK cells were co-cultured with A549 and H1975 cell lines in the presence of gefitinib. NKG2D ligands, ULBP1, ULBP2, MICA, and MHC-I on tumor cells, and NKG2D, NKp44 and NKp46 on NK cells were evaluated with flow cytometry. 51Cr release assay was performed when NKG2D antibody were added into the co-culture system. Expressions of stat3 and LC3 I/II on tumor cells were determined with western blot after co-cultured with NK cells. After treated with gefitinib, mannose-6-phosphate receptor (MPR) on H1975 cells was evaluated by flow cytometry. 51Cr release assay were performed when MPR antagonist were used.ResultsGefitinib increased cytotoxicity of NK cells to human lung cancer H1975 cells with EGFR L858R + T790M mutations, while not in A549 cells with wild type EGFR. Gefitinib could block the immune escape by up-regulating the expression of NKG2D ligands ULBP1, ULBP2 or MICA on tumor cells and NKG2D on NK cells in the co-culture system. Gefitinib and NK cells up-regulated MHC-I expression in A549 while not in H1975 cells. NKG2D antibody blocked the enhanced NK cytotoxicity by gefitinib. The combination of NK cells and gefitinib could significantly down-regulate stat3 expression. Furthermore, NK cells-mediated tumor cell autophagy was observed in A549 cells while not in H1975 cells. Notably, gefitinib increased autophagy and MPR expression in H1975 cells, which improved the sensitivity to NK cell-based immunotherapy.ConclusionsGefitinib greatly enhanced NK cell cytotoxicity to lung cancer cells with EGFR L858R + T790M resistance mutation. Combination of EGFR tyrokinase inhibitors and NK cells adoptive immunotherapy may represent a potentially effective strategy for patients with non-small cell lung cancer.

Hemorrhage is a common clinical manifestation in patients with cancer. Intratumor hemorrhage has been demonstrated to be a poor prognostic factor for cancer patients. In this study, we investigated the role of RBCs and hemoglobin (Hb) in the process of tumor progression and therapeutical response. RBCs and Hb potently promoted tumor cell proliferation and syngenic tumor growth. RBCs and Hb activated the reactive oxygen species–NF-κB pathway in both tumor cells and macrophages. RBCs and Hb also induced chemoresistance mediated, in part, by upregulating ABCB1 gene expression. Tumor growth induced by RBCs was accompanied by an inflammatory signature, increased tumor vasculature, and influx of M2 macrophages. In both the peritoneal cavity and tumor microenvironment, extravascular RBCs rapidly recruited monocyte–macrophages into the lesion sites. In addition, RBCs and Hb increased several nucleotide-binding oligomerization domain–like receptors' expression and induced IL-1β release. Our results provide novel insights into the protumor function of RBCs and Hb as endogenous danger signals, which can promote tumor cell proliferation, macrophage recruitment, and polarization. Hemorrhage may represent a useful prognostic factor for cancer patients because of its role in tumor promotion and chemoresistance.

Background: Elevated PNAS-4 induces S phase arrest and apoptosis in vitro and inhibits tumor growth in vivo. Results: PNAS-4 activates Chk1/2 to cause inhibition of the Cdc25A-CDK2-cyclin E/A pathway, causing S phase arrest and apoptosis. Conclusion: Activation of Chk1/2 is a determinant of S phase arrest and apoptosis. Significance: We provide a novel action mechanism for PNAS-4 as a potential therapeutic target for lung cancer.

Identification of endogenous angiogenesis inhibitors has led to development of an increasingly attractive strategy for cancer therapy and other angiogenesis-driven diseases. Vascular endothelial growth inhibitor (VEGI), a potent and relatively nontoxic endogenous angiogenesis inhibitor, has been intensively studied, and this work shed new light on developing promising anti-angiogenic strategies. It is well-documented that the RGD (Arg-Gly-Asp) motif exhibits high binding affinity to integrin α(v)β(3), which is abundantly expressed in cancer cells and specifically associated with angiogenesis on tumors. Here, we designed a fusion protein containing the special RGD-4C motif sequence and VEGI-192, aimed at offering more effective multiple targeting to tumor cells and tumor vasculature, and higher anti-angiogenic and antitumor efficacy. Functional tests demonstrated that the purified recombinant human RGD-VEGI-192 protein (rhRGD-VEGI-192) potently inhibited endothelial growth in vitro and suppressed neovascularization in chicken chorioallantoic membrane in vivo, to a higher degree as compared with rhVEGI-192 protein. More importantly, rhRGD-VEGI-192, but not rhVEGI-192 protein, could potentially target MDA-MB-435 breast tumor cells, significantly inhibiting growth of MDA-MB-435 cells in vitro, triggered apoptosis in MDA-MB-435 cells by activation of caspase-8 as well as caspase-3, which was mediated by activating the JNK signaling associated with upregulation of pro-apoptotic protein Puma, and consequently led to the observed significant antitumor effect in vivo against a human breast cancer xenograft. Our study indicated that the RGD-VEGI-192 fusion protein might represent a novel anti-angiogenic and antitumor strategy.