The overexpression of HER2/neu and EGFR receptors plays important roles in tumorigenesis and tumor progression. Targeting these two receptors simultaneously can have a more widespread application in early diagnosis of cancers. In this study, a new multifunctional nanoparticles (MnMEIO-CyTE777-(Bis)-mPEG NPs) comprising a manganese-doped iron oxide nanoparticle core (MnMEIO), a silane-amino functionalized poly(ethylene glycol) copolymer shell, a near infrared fluorescence dye (CyTE777), and a covalently conjugated anti-HER2/neu and anti-EGFR receptors bispecific antibody (Bis) were successfully developed. In vitro T2-weighted MR imaging studies in SKBR-3 and A431 tumor cells incubated with MnMEIO-CyTE777-(Bis)-mPEG NPs showed - 94.8 ± 3.8 and - 84.1 ± 2.8% negative contrast enhancement, respectively. Pharmacokinetics study showed that MnMEIO-CyTE777-(Bis)-mPEG NPs were eliminated from serum with the half-life of 21.3 mins. In vivo MR imaging showed that MnMEIO-CyTE777-(Bis)-mPEG NPs could specifically and effectively target to HER2/neu- and EGFR-expressing tumors in mice; the relative contrast enhancements were 11.8 (at 2 hrs post-injection) and 61.5 (at 24 hrs post-injection) fold higher in SKBR-3 tumors as compared to Colo-205 tumors. T2-weighted MR and optical imaging studies revealed that the new contrast agent (MnMEIO-CyTE777-(Bis)-mPEG NPs) could specifically and effectively target to HER2/neu- and/or EGFR-expressing tumors. Our results demonstrate that MnMEIO-CyTE777-(Bis)-mPEG NPs are able to recognize the tumors expressing both HER2/neu and/or EGFR, and may provide a novel molecular imaging tool for early diagnosis of cancers expressing HER2/neu and/or EGFR.

One of the major challenges in the hepatocellular carcinoma (HCC) treatment is its insensitivity to chemotherapeutic drugs. Here, we report the development of novel lipid-coated cisplatin nanoparticles co-loaded with microRNA-375 (NPC/miR-375) as a potential treatment for chemotherapy insensitive HCC. The NPC/miR-375 was fabricated by mixing two reverse microemulsions containing KCl solution and a highly soluble cis-diaminedihydroplatinum (II) coated with a cationic lipid layer. Subsequently, the miR-375 was incorporated into the lipid-coated cisplatin nanoparticles. The NPC/miR375 nanoparticles were expected to further decrease cell proliferation and to enhance the anti-tumor effect of cisplatin in chemotherapy resistant HCC cells. In vitro analysis of intracellular trafficking revealed that NPC/miR-375 were able to escape from the late endosomes instead of lysosomes thus avoiding degradation of the miR-375 in lysosomes. Importantly, NPC/miR-375 enhanced apoptosis and induced cell cycle arrest in HCC cells in vitro. In the double oncogenes Akt/Ras-induced primary HCC mouse model, multiple doses of NPC/miR-375 significantly inhibited tumor growth and delayed the tumor relapse. Our results indicate that cisplatin nanoparticles co-loaded with miR-375 represent a potential therapeutic agent for chemotherapy-insensitive HCC.

Photoacoustic (PA) imaging and photothermal therapy (PTT) as light-induced theranostic platforms have been attracted much attention in recent years. However, the development of highly efficient and integrated phototheranostic nanoagents for amplifying PA imaging and PTT treatments poses great challenges. Here, we report a novel phototheranostic nanoagent using indocyanine green-loaded polydopamine-reduced graphene oxide nanocomposites (ICG-PDA-rGO) with amplifying PA and PTT effects for cancer theranostics. The results demonstrate that the PDA layer coating on the surface of rGO could effectively absorb a large number of ICG molecules, quench ICG's fluorescence, and enhance the PDA-rGO's optical absorption at 780 nm. The obtained ICG-PDA-rGO exhibits stronger PTT effect and higher PA contrast than that of pure GO and PDA-rGO. After PA imaging-guided PTT treatments, the tumors in 4T1 breast subcutaneous and orthotopic mice models are suppressed completely and no treatment-induced toxicity being observed. It illustrates that the ICG-PDA-rGO nanocomposites constitute a new class of theranostic nanomedicine for amplifying PA imaging and PTT treatments.

Minoxidil (Mx) is a conventional drug for treating androgenetic alopecia, preventing hair loss, and promoting hair growth. The solubility of Mx has been improved using chemical enhancement methods to increase its skin permeability over the long term. This study created a new ultrasound (US) contrast agent-albumin-shelled microbubbles (MBs) that absorb chitosan oligosaccharide lactate (COL) and Mx-and combined it with sonication by US energy in the water phase to enhance hair growth while shortening the treatment period. COL and Mx grafted with MBs (mean diameter of 1480 nm) were synthesized into self-assembled complexes of COL-MBs and Mx-COL-MBs that had mean diameters of 4150 and 4500 nm, respectively. The US was applied at 3 W/cm(2) for 1 min, and combined with Mx-COL-MBs containing 0.3% Mx. The diffusion of Mx through the dialysis membrane from Mx-COL-MB during US (US+Mx-COL-MB) was more rapid at pH 4 than at pH 7.4, which is favorable given that the environment of the scalp is mildly acidic (pH=4.5-5.5). In Franz diffusion experiments performed in vitro, the release rates at 18 hours in the US+Mx-COL-MBs and US+MBs+Mx groups resulted in 2.3 and 1.7 times the penetration and deposition, respectively, of Mx relative to the group with Mx alone. During 21 days treatment in animal experiments, the growth rates at days 10 and 14 in the US+Mx-COL-MBs group increased by 22.6% and 64.7%, respectively, and there were clear significant differences (p<0.05) between the US+Mx-COL-MBs group and the other four groups. The use of US+Mx-COL-MB in the water phase can increased the effects of Mx so as to shorten the telogen phase, and also increase both the diameter of keratinized hair shafts and the size of hair follicles without causing skin damage.

Baroreflex is the physiological mechanism for the maintenance of blood pressure and heart rate. Impairment of baroreflex is not a disease per se. However, depending on severity, the eventuality of baroreflex dysfunction varies from inconvenience in daily existence to curtailment of mobility to death. Despite universal acceptance, neuronal traffic within the contemporary neural circuits during the execution of baroreflex has never been visualized. By enhancing signal detection and fine-tuning the scanning parameters, we have successfully implemented tractographic analysis of the medulla oblongata in mice that allowed for visualization of connectivity between key brain stem nuclei in the baroreflex circuits. When viewed in conjunction with radiotelemetric analysis of the baroreflex, we found that under pathophysiological conditions when the disrupted connectivity between key nuclei in the baroreflex circuits was reversible, the associated disease condition (e.g. neurogenic hypertension) was amenable to remedial measures. Nevertheless, fatality ensues under pathological conditions (e.g. hepatic encephalopathy) when the connectivity between key substrates in the baroreflex circuits was irreversibly severed. MRI/DTI also prompted partial re-wiring of the contemporary circuit for baroreflex-mediated sympathetic vasomotor tone, and unearthed an explanation for the time lapse between brain death and the inevitable asystole signifying cardiac death that follows.

Cerebral malaria (CM) is a major cause of death of Plasmodium falciparum infection. Misdiagnosis of CM often leads to treatment delay and mortality. Conventional brain imaging technologies are rarely applicable in endemic areas. Here we address the unmet need for a simple, non-invasive imaging methodology for early diagnosis of CM. This study presents the diagnostic and therapeutic monitoring using liposomes containing the FDA-approved fluorescent dye indocyanine green (ICG) in a CM murine model. Increased emission intensity of liposomal ICG was demonstrated in comparison with free ICG. The Liposomal ICG's emission was greater in the brains of the infected mice compared to naïve mice and drug treated mice (where CM was prevented). Histological analyses suggest that the accumulation of liposomal ICG in the cerebral vasculature is due to extensive uptake mediated by activated phagocytes. Overall, liposomal ICG offers a valuable diagnostic tool and a biomarker for effectiveness of CM treatment, as well as other diseases that involve inflammation and blood vessel occlusion.

Cell penetrating peptides (CPPs) were widely used for drug delivery to tumor. However, the nonselective in vivo penetration greatly limited the application of CPPs-mediated drug delivery systems. And the treatment of malignant tumors is usually followed by poor prognosis and relapse due to the existence of extravascular core regions of tumor. Thus it is important to endue selective targeting and stronger intratumoral diffusion abilities to CPPs. In this study, an RGD reverse sequence dGR was conjugated to a CPP octa-arginine to form a CendR (R/KXXR/K) motif contained tandem peptide R8-dGR (RRRRRRRRdGR) which could bind to both integrin αvβ3 and neuropilin-1 receptors. The dual receptor recognizing peptide R8-dGR displayed increased cellular uptake and efficient penetration ability into glioma spheroids in vitro. The following in vivo studies indicated the active targeting and intratumoral diffusion capabilities of R8-dGR modified liposomes. When paclitaxel was loaded in the liposomes, PTX-R8-dGR-Lip induced the strongest anti-proliferation effect on both tumor cells and cancer stem cells, and inhibited the formation of vasculogenic mimicry channels in vitro. Finally, the R8-dGR liposomal drug delivery system prolonged the medium survival time of intracranial C6 bearing mice by 2.1-fold compared to the untreated group, and achieved an exhaustive anti-glioma therapy including anti-tumor cells, anti-vasculogenic mimicry and anti-brain cancer stem cells. To sum up, all the results demonstrated that R8-dGR was an ideal dual receptor recognizing CPP with selective glioma targeting and efficient intratumoral diffusion, which could be further used to equip drug delivery system for effective glioma therapy.

Multiple myeloma (MM) remains an essentially incurable hematologic malignancy originating from clonal plasma cells. This study evaluated the usefulness of the radiotracers (11)C-methionine (MET) and (18)F-2`-deoxy-2`-fluorodeoxyglucose (FDG) for staging and re-staging in MM. 43 patients with MM underwent both MET- and FDG-PET/CT for staging or re-staging within 3±2 days. Scans were compared on a patient and on a lesion basis. Tracer uptake was correlated with the degree of bone marrow (BM) involvement and standard clinical parameters of disease activity. Additionally, BM samples were stained for L-type amino acid transporter 1 (LAT1) expression in 15 patients. MET-PET detected focal lesions (FL) in 39/43 subjects (90.7%), whereas 10 patients were missed in FDG-PET/CT (detection rate, 33/43; 76.7%; p<0.05). MET depicted more FL in 28/43 patients (65.1%; p<0.001), whereas in the remainder (34.9%, n=15) both tracers yielded comparable results. LAT1 was highly expressed on the cell surface of myeloma cells. Both FDG and MET uptake correlated significantly with biopsy-proven BM involvement (p<0.001), with MET demonstrating a stronger correlation (SUVmean, r=0.9 vs r=0.6; SUVmax, r=0.88 vs r=0.58). Abnormal beta-2-microglobulin and free light chain levels correlated with the presence of focal intramedullary lesions detected in MET- or FDG-PET/CT (MET, p=0.006 and p=0.01, respectively; FDG, p=0.02 and p=0.01). MET appears to be superior to FDG for staging and re-staging of both intra- and extramedullary MM lesions. Tracer uptake correlates with BM involvement, β2m and FLC levels and appears to be a more accurate marker of tumor burden and disease activity.

Many types of biocompatible nanomaterials have proven of low cytotoxicity and hold great promise for various applications in nanomedicine. Whereas they generally do not cause apparent organ toxicity or tissue damage in adult animals, it is yet to determine their biological consequences in more general contexts. In this study, we investigate how silica nanoparticles (NPs) affect cellular activities and functions under several physiological or pathological conditions. Although silica NPs are generally regarded as "inert" nanocarriers and widely employed in biomedical studies, we find that they actively affect Wnt signaling in various types of cell lines, diminishing its anti-adipogenic effect in preadipocytes and pro-invasive effect in breast cancer cells, and more significantly, impair Wnt-regulated embryonic development in Zebrafish. We further demonstrate that intracellular silica NPs block Wnt signal transduction in a way resembling signaling molecules. Specifically, silica NPs target the Dvl protein, a key component of Wnt signaling cascade, for lysosomal degradation. As Wnt signaling play significant roles in embryonic development and adipogenesis, the observed physiological effects beyond toxicity imply potential risk of obesity, or developmental defects in somitogenesis and osteogenesis upon exposure to silica NPs. In addition, given the clinical implications of Wnt signaling in tumorigenesis and cancer metastasis, our work also establishes for the first time a molecular link between nanomaterials and the Wnt signaling pathway, which opens new door for novel applications of unmodified silica NPs in targeted therapy for cancers and other critical illness.

Single-walled carbon nanotubes (SWNTs) with various unique properties have attracted great attention in cancer theranostics. Herein, SWNTs are coated with a shell of polydopamine (PDA), which is further modified by polyethylene glycol (PEG). The PDA shell in the obtained SWNT@PDA-PEG could chelate Mn(2+), which together with metallic nanoparticulate impurities anchored on SWNTs offer enhanced both T1 and T2 contrasts under magnetic resonance (MR) imaging. Meanwhile, also utilizing the PDA shell, radionuclide (131)I could be easily labeled onto SWNT@PDA-PEG, enabling nuclear imaging and radioisotope cancer therapy. As revealed by MR & gamma imaging, efficient tumor accumulation of SWNT@PDA-(131)I-PEG is observed after systemic administration into mice. By further utilizing the strong near-infarared (NIR) absorbance of SWNTs, NIR-triggered photothermal therapy in combination with (131)I-based radioisotope therapy is realized in our animal experiments, in which a remarkable synergistic antitumor therapeutic effect is observed compared to monotherapies. Our work not only presents a new type of theranostic nanoplatform based on SWNTs, but also suggests the promise of PDA coating as a general approach to modify nano-agents and endow them with highly integrated functionalities.

Circulating tumor cells (CTCs) have been considered as the origin of cancer metastasis. Thus, detection of CTCs in peripheral blood is of great value in different types of solid tumors. However, owing to extremely low abundance of CTCs, detection of them has been technically challenging. To establish a simple and efficient method for CTCs detection in patients with hepatocellular carcinoma (HCC), we applied biocompatible and transparent HA/CTS (Hydroxyapatite/chitosan) nanofilm to achieve enhanced topographic interactions with nanoscale cellular surface components, and we used sLex-AP (aptamer for carbohydrate sialyl Lewis X) to coat onto HA/CTS nanofilm for efficient capture of HCC CTCs, these two functional components combined to form our CTC-(BioT)Chip platform. Using this platform, we realized HCC CTCs' capture and identification, the average recovery rate was 61.6% or more at each spiking level. Importantly, our platform identified CTCs (2±2 per 2 mL) in 25 of 42 (59.5%) HCC patients. Moreover, both the positivity rate and the number of detected CTCs were significantly correlated with tumor size, portal vein tumor thrombus, and the TNM (tumor-node-metastasis) stage. In summary, our CTC-(BioT)Chip platform provides a new method allowing for simple but efficient detection of CTCs in HCC patients, and it holds potential of clinically usefulness in monitoring HCC prognosis and guiding individualized treatment in the future.

Mesenchymal stem cells (MSCs) are promising candidates for tissue regeneration and disease treatment. However, long-term in vitro passaging leads to stemness loss of MSCs, resulting in failure of MSCs therapy. Here, we report a melatonin-based strategy to improve cell therapy of in vitro cultured MSCs. Among four small molecules with anti-aging and stem cell-protection properties (rapamycin, resveratrol, quercetin and melatonin), colony forming, proliferation, and osteogenic differentiation assay showed that melatonin was the most efficient to preserve self-renewal and differentiation properties of rat bone marrow MSCs (BMMSCs) after long-term passaging. Functional assays confirmed melatonin treatment did not affect the colony forming, proliferation and osteogenic differentiation of BMMSCs cultured for 1 or 4 passages, but largely prevented the decline of self-renew and differentiation capacity of BMMSCs cultured for 15 passages in vitro. Furthermore, heterotopic osteogenesis assay, critical size calvarial defects repair assay, osteoporosis treatment and experimental colitis therapy assay strongly certified that melatonin preserved the therapeutic effect of long-term passaged BMMSCs on bone regeneration and immunotherapy in vivo. Mechanistically, melatonin functioned by activating antioxidant defense system, inhibiting the pathway of cell senescence, and preserving the expression of gene governing the stemness. Taken together, our findings showed that melatonin treatment efficiently prevented the dysfunction and therapeutic failure of BMMSCs after long-term passaging, providing a practical strategy to improve the application of BMMSCs in tissue engineering and cytotherapy.

Quiescent leukemia stem cells (LSCs) that are insensitive to BCR-ABL tyrosine kinase inhibitors confer resistance to imatinib in chronic myelogenous leukemia (CML). Identifying proteins to regulate survival and stemness of LSCs is urgently needed. Although histone deacetylase inhibitors (HDACis) can eliminate quiescent LSCs in CML, little is known about the underlying mechanism that HDACis kill LSCs. By fishing with a biotin-labeled probe, we identified that HDACi JSL-1 bound to the protein γ-catenin. γ-Catenin expression was higher in LSCs from CML patients than normal hematopoietic stem cells. Silencing γ-catenin in human CML CD34(+) bone-marrow (BM) cells sufficiently eliminated LSCs, which suggests that γ-catenin is required for survival of CML LSCs. Pharmacological inhibition of γ-catenin thwarted survival and self-renewal of human CML CD34(+) cells in vitro, and of murine LSCs in BCR-ABL-driven CML mice. γ-Catenin inhibition reduced long-term engraftment of human CML CD34(+) cells in NOD.Cg-Prkdc (scid) II2rg (tm1Sug)/JicCrl (NOG) mice. Silencing γ-catenin by shRNA in human primary CD34(+) cells did not alter β-catenin, implying a β-catenin-independent role of γ-catenin in survival and self-renewal of CML LSCs. Taken together, our findings validate that γ-catenin may be a novel therapeutic target of LSCs, and suppression of γ-catenin by HDACi may explain elimination of CML LSCs.

Recently, self-assembling small dendrimers into supramolecular dendritic systems offers an alternative strategy to develop multifunctional nanoplatforms for biomedical applications. We herein report a dual-responsive supramolecular PEGylated dendritic system for efficient platinum-based drug delivery and near-infrared (NIR) tracking. With a refined molecular/supramolecular engineering, supramolecular dendritic systems were stabilized by bioreducible disulfide bonds and endowed with NIR fluorescence probes, and PEGylated platinum derivatives coordinated onto the abundant peripheral groups of supramolecular dendritic templates to generate pH/redox dual-responsive theranostic supramolecular PEGylated dendritic systems (TSPDSs). TSPDSs markedly improved the pharmacokinetics and biodistribution of platinum-based drugs, owing to their stable nanostructures and PEGylated shells during the blood circulation. Tumor intracellular environment (low pH value and high glutathione concentration) could trigger the rapid disintegration of TSPDSs due to acid-labile coordination bonds and redox-cleavable disulfide linkages, and then platinum-based drugs were delivered into the nuclei to exert antitumor activity. In vivo antitumor treatments indicated TSPDSs not only provided high antitumor efficiency which was comparable to clinical cisplatin, but also reduced renal toxicity of platinum-based drugs. Moreover, NIR fluorescence of TSPDSs successfully visualized in vitro and in vivo fate of nanoplatforms and disclosed the intracellular platinum delivery and pharmacokinetics. These results confirm tailor-made supramolecular dendritic system with sophisticated nanostructure and excellent performance is a promising candidate as smart theranostic nanoplatforms.

Photodynamic therapy (PDT) is a promising non-invasive therapeutic modality that has been proposed for treating prostate cancer, but the procedure is associated with limited efficacy, tumor recurrence and photo-toxicity. In the present study, we proposed to develop a novel multifunctional nano-platform for targeted delivery of heat, reactive oxygen species (ROS) and heat shock protein 90 (Hsp90) inhibitor simultaneously for combination therapy against prostate cancer. This new nano-platform combines two newly developed entities: 1) a unique organic and biocompatible nanoporphyrin-based drug delivery system that can generate efficient heat and ROS simultaneously with light activation at the tumor sites for dual-modal photothermal- and photodynamic- therapy (PTT/PDT), and 2) new nano-formulations of Hsp90 inhibitors that can decrease the levels of pro-survival and angiogenic signaling molecules induced by phototherapy, therefore, further sensitizing cancer cells to phototherapy. Furthermore, the nanoparticles have activatable near infrared (NIR) fluorescence for optical imaging to conveniently monitor the real-time drug delivery in both subcutaneous and orthotopic mouse models bearing prostate cancer xenograft. This novel multifunctional nano-platform has great potential to improve the care of prostate cancer patients through targeted combination therapy.

The phenylboronic acid-conjugated chitosan nanoparticles were prepared by particle surface modification. The size, zeta potential and morphology of the nanoparticles were characterized by dynamic light scattering, zeta potential measurement and transmission electron microscopy. The cellular uptake, tumor penetration, biodistribution and antitumor activity of the nanoparticles were evaluated by using monolayer cell model, 3-D multicellular spheroid model and H22 tumor-bearing mice. The incorporation of phenylboronic acid group into chitosan nanoparticles impart a surface charge-reversible characteristic to the nanoparticles. In vitro evaluation using 2-D and 3-D cell models showed that phenylboronic acid-decorated nanoparticles were more easily internalized by tumor cells compared to non-decorated chitosan nanoparticles, and could deliver more drug into tumor cells due to the active targeting effect of boronic acid group. Furthermore, the phenylboronic acid-decorated nanoparticles displayed a deeper penetration and persistent accumulation in the multicellular spheroids, resulting in better inhibition growth to multicellular spheroids than non-decorated nanoparticles. Tumor penetration, drug distribution and near infrared fluorescence imaging revealed that phenylboronic acid-decorated nanoparticles could penetrate deeper and accumulate more in tumor area than non-decorated ones. In vivo antitumor examination demonstrated that the phenylboronic acid-decorated nanoparticles have superior efficacy in restricting tumor growth and prolonging the survival time of tumor-bearing mice than free drug and drug-loaded chitosan nanoparticles.

In vivo optical spatio-temporal imaging of the tumor microenvironment is useful to explain how tumor immunotherapies work. However, the lack of fluorescent antigens with strong immunogenicity makes it difficult to study the dynamics of how tumors are eliminated by any given immune response. Here, we develop an effective fluorescent model antigen based on the tetrameric far-red fluorescent protein KatushkaS158A (tfRFP), which elicits both humoral and cellular immunity. We use this fluorescent antigen to visualize the dynamic behavior of immunocytes as they attack and selectively eliminate tfRFP-expressing tumors in vivo; swarms of immunocytes rush toward tumors with high motility, clusters of immunocytes form quickly, and numerous antigen-antibody complexes in the form of tfRFP(+) microparticles are generated in the tumor areas and ingested by macrophages in the tumor microenvironment. Therefore, tfRFP, as both a model antigen and fluorescent reporter, is a useful tool to visualize specific immune responses in vivo.

Unnatural sugar-mediated metabolic labeling of cancer cells, coupled with efficient Click chemistry, has shown great potential for in vivo imaging and cancer targeting. Thus far, chemical labeling of cancer cells has been limited to the small-sized azido groups, with the large-sized and highly hydrophobic dibenzocyclooctyne (DBCO) being correspondingly used as the targeting ligand. However, surface modification of nanomedicines with DBCO groups often suffers from low ligand density, difficult functionalization, and impaired physiochemical properties. Here we report the development of DBCO-bearing unnatural sugars that could directly label LS174T colon cancer cells with DBCO groups and subsequently mediate cancer-targeted delivery of azido-modified silica nanoconjugates with easy functionalization and high azido density in vitro and in vivo. This study, for the first time, demonstrates the feasibility of metabolic labeling of cancer cells with large-sized DBCO groups for subsequent, efficient targeting of azido-modified nanomedicines.

The pharmacokinetics of small interfering RNAs (siRNAs) is a pivotal issue for siRNA-based drug development. In this study, we comprehensively investigated the behavior of siRNAs in vivo in various tissues and demonstrated that intravenously-injected naked siRNA accumulated remarkably in the submandibular gland, bulbourethral gland, and pancreas, with a respective half-life of ~22.7, ~45.6, and ~30.3 h. This was further confirmed by gel separation of tissue homogenates and/or supernatants. In vivo imaging and cryosectioning suggested that delivery carriers significantly influence the distribution and elimination profiles of siRNA. Gene-silencing assays revealed that neither naked nor liposome-formulated siRNA resulted in gene knockdown in the submandibular and bulbourethral glands after systemic administration, suggesting that these glands function as drug reservoirs that enable slow siRNA release into the circulation. But robust gene-silencing was achieved by local injection of liposome-encapsulated siRNA into the submandibular gland. Our results enhance understanding of the pharmacokinetic properties of siRNAs and we believe that they will facilitate the development of siRNA therapy, especially for the submandibular gland.

Bacteria-based anticancer therapies aim to overcome the limitations of current cancer therapy by actively targeting and efficiently removing cancer. To achieve this goal, new approaches that target and maintain bacterial drugs at sufficient concentrations during the therapeutic window are essential. Here, we examined the tumor tropism of attenuated Salmonella typhimurium displaying the RGD peptide sequence (ACDCRGDCFCG) on the external loop of outer membrane protein A (OmpA). RGD-displaying Salmonella strongly bound to cancer cells overexpressing αvβ3, but weakly bound to αvβ3-negative cancer cells, suggesting the feasibility of displaying a preferential homing peptide on the bacterial surface. In vivo studies revealed that RGD-displaying Salmonellae showed strong targeting efficiency, resulting in the regression in αvβ3-overexpressing cancer xenografts, and prolonged survival of mouse models of human breast cancer (MDA-MB-231) and human melanoma (MDA-MB-435). Thus, surface engineering of Salmonellae to display RGD peptides increases both their targeting efficiency and therapeutic effect.