skip to main content


Title: Engineered bacteria detect spatial profiles in glucose concentration within solid tumor cell masses
ABSTRACT   more » « less
NSF-PAR ID:
10236780
Author(s) / Creator(s):
 ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Biotechnology and Bioengineering
Volume:
113
Issue:
11
ISSN:
0006-3592
Page Range / eLocation ID:
p. 2474-2484
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Combining the specificity of tumor‐targeting bacteria with the sensitivity of biomarker detection would create a screening method able to detect small tumors and metastases. To create this system, we genetically modified an attenuated strain ofSalmonella entericato release a recombinant fluorescent biomarker (or fluoromarker).Salmonellaexpressing ZsGreen were intravenously administered to tumor‐bearing mice and fluoromarker production was induced after 48 hr. The quantities and locations of bacteria and ZsGreen were measured in tumors, livers and spleens by immunofluorescence, and the plasma concentration of ZsGreen was measured using single‐layer ELISA. In the plasma, the ZsGreen concentration was in the range of 0.5–1.5 ng/ml and was dependent on tumor mass (with a proportion of 0.81 ± 0.32 ng·ml−1·g−1). No adverse reaction to ZsGreen or bacteria was observed in any mice. ZsGreen was released at an average rate of 4.3 fg·CFU−1·hr−1and cleared from the plasma with a rate constant of 0.259 hr−1. ZsGreen production was highest in viable tissue (7.6 fg·CFU−1·hr−1) and lowest in necrotic tissue (0.47 fg·CFU−1·hr−1). The mass transfer rate constant from tumor to blood was 0.0125 hr−1. Based on these measurements, this system has the capability to detect tumors as small as 0.12 g. These results demonstrate four essential mechanisms of this method: (i) preferential tumor colonization by bacteria, (ii) fluoromarker releasein vivo, (iii) fluoromarker transport through tumor tissue and (iv) slow enough systemic clearance to enable measurement. This bacteria‐based blood test would be minimally invasive and has the potential to identify previously undetectable microscopic tumors.

     
    more » « less
  2. Abstract

    Poly(lactic acid) (PLA) and its copolymer, poly(lactic‐co‐glycolic acid) (PLGA), based aliphatic polyesters have been extensively used for biomedical applications, such as drug delivery system and tissue engineering, thanks to their biodegradability, benign toxicity, renewability, and adjustable mechanical properties. A rapidly growing field of cancer research, the development of therapeutic cancer vaccines or treatment modalities is aimed to deliver immunomodulatory signals that control the quality of immune responses against tumors. Herein, the progress and applications of PLA and PLGA are reviewed in delivering immunotherapeutics to treat cancers.

     
    more » « less
  3. Introduction: Skin Cancer is the most common cancer by which people are afflicted. While most forms of skin cancer have high survival rates if they are caught early, both Squamous Cell Carcinoma and Melanoma can metastasize and are very difficult to treat once this happens. Matrix Metallopeptidases (MMPs), Normally involved in cell growth, movement, and death, can become overactive in patients with cancer. While research suggested that MMP inhibitors could be used to treat many forms of cancer, clinical trials in late stage cancer patients showed that this was not the case. While they were not useful in shrinking late stage tumors, they were effective in preventing growth and metastasis of existing tumors. For this reason, they may be especially useful in the treatment of skin cancers as they may prevent metastasis. While MMP inhibitors can be delivered systemically, whether orally, or intravenously, systemic delivery can give rise to severe unwanted off-target side effects. As such, localized delivery is preferable. By incorporating MMP inhibitors into polymer gels, the drug can be administered topically and its distribution within the skin and into the systemic circulation may be controlled. Formulations may therefore be customized to alter the depth which the drug is delivered. 
    more » « less
  4. Introduction

    Immunotherapies have shown great promise, but are not effective for all tumors types and are effective in less than 3% of patients with pancreatic ductal adenocarcinomas (PDAC). To make an immune treatment that is effective for more cancer patients and those with PDAC specifically, we genetically engineered Salmonella to deliver exogenous antigens directly into the cytoplasm of tumor cells. We hypothesized that intracellular delivery of an exogenous immunization antigen would activate antigen-specific CD8 T cells and reduce tumors in immunized mice.

    Methods

    To test this hypothesis, we administered intracellular delivering (ID) Salmonella that deliver ovalbumin as a model antigen into tumor-bearing, ovalbumin-vaccinated mice. ID Salmonella delivers antigens by autonomously lysing in cells after the induction of cell invasion.

    Results

    We showed that the delivered ovalbumin disperses throughout the cytoplasm of cells in culture and in tumors. This delivery into the cytoplasm is essential for antigen cross-presentation. We showed that co-culture of ovalbumin-recipient cancer cells with ovalbumin-specific CD8 T cells triggered a cytotoxic T cell response. After the adoptive transfer of OT-I CD8 T cells, intracellular delivery of ovalbumin reduced tumor growth and eliminated tumors. This effect was dependent on the presence of the ovalbumin-specific T cells. Following vaccination with the exogenous antigen in mice, intracellular delivery of the antigen cleared 43% of established KPC pancreatic tumors, increased survival, and prevented tumor re-implantation.

    Discussion

    This response in the immunosuppressive KPC model demonstrates the potential to treat tumors that do not respond to checkpoint inhibitors, and the response to re-challenge indicates that new immunity was established against intrinsic tumor antigens. In the clinic, ID Salmonella could be used to deliver a protein antigen from a childhood immunization to refocus pre-existing T cell immunity against tumors. As an off-the-shelf immunotherapy, this bacterial system has the potential to be effective in a broad range of cancer patients.

     
    more » « less
  5. Abstract

    Clinical treatment of cancer commonly incorporates X‐ray radiation therapy (XRT), and developing spatially precise radiation‐activatable drug delivery strategies may improve XRT efficacy while limiting off‐target toxicities associated with systemically administered drugs. Nevertheless, achieving this has been challenging thus far because strategies typically rely on radical species with short lifespans, and the inherent nature of hypoxic and acidic tumor microenvironments may encourage spatially heterogeneous effects. It is hypothesized that the challenge could be bypassed by using scintillating nanoparticles that emit light upon X‐ray absorption, locally forming therapeutic drug depots in tumor tissues. Thus a nanoparticle platform (Scintillating nanoparticleDrugDepot; SciDD) that enables the local release of cytotoxic payloads only after activation by XRT is developed, thereby limiting off‐target toxicity. As a proof‐of‐principle, SciDD is used to deliver a microtubule‐destabilizing payload MMAE (monomethyl auristatin E). With as little as a 2 Gy local irradiation to tumors, MMAE payloads are released effectively to kill tumor cells. XRT‐mediated drug release is demonstrated in multiple mouse cancer models and showed efficacy over XRT alone (p < 0.0001). This work shows that SciDD can act as a local drug depot with spatiotemporally controlled release of cancer therapeutics.

     
    more » « less