During cancer cell invasion, faster moving cancer cells play a dominant role by invading further and metastasizing earlier. Despite the importance of these outlier cells, the source of heterogeneity ...in their migratory behavior remains poorly understood. Here, we show that anterior localization of mitochondria, in between the nucleus and the leading edge of migrating epithelial cancer cells, correlates with faster migration velocities and increased directional persistence. The asymmetry of mitochondrial localization along the axis of migration is absent during spontaneous cell migration on two-dimensional surfaces and only occurs in the presence of chemical attractant cues or in conditions of mechanical confinement. Moreover, perturbing the asymmetric distribution of mitochondria within migrating cells by interfering with mitochondrial fusion (opa-1) or fission (drp-1) proteins, significantly reduces the number of cells with anterior localization of mitochondria and significantly decreases the velocity and directional persistence of the fastest moving cells. We also observed similar changes after perturbing the linkage between mitochondria and microtubules by the knockdown of mitochondrial rhoGTPase-1 (miro-1). Taken together, the changes in migration velocity and directional persistence in cells with anterior-localized mitochondria could account for an order of magnitude differences in invasive abilities between cells from otherwise homogenous cell populations.
Microfluidic organs-on-chips Bhatia, Sangeeta N; Ingber, Donald E
Nature biotechnology,
08/2014, Letnik:
32, Številka:
8
Journal Article
Recenzirano
An organ-on-a-chip is a microfluidic cell culture device created with microchip manufacturing methods that contains continuously perfused chambers inhabited by living cells arranged to simulate ...tissue- and organ-level physiology. By recapitulating the multicellular architectures, tissue-tissue interfaces, physicochemical microenvironments and vascular perfusion of the body, these devices produce levels of tissue and organ functionality not possible with conventional 2D or 3D culture systems. They also enable high-resolution, real-time imaging and in vitro analysis of biochemical, genetic and metabolic activities of living cells in a functional tissue and organ context. This technology has great potential to advance the study of tissue development, organ physiology and disease etiology. In the context of drug discovery and development, it should be especially valuable for the study of molecular mechanisms of action, prioritization of lead candidates, toxicity testing and biomarker identification.
The recent advent of immune checkpoint inhibitor (CPI) antibodies has revolutionized many aspects of cancer therapy, but the efficacy of these breakthrough therapeutics remains limited, as many ...patients fail to respond for reasons that still largely evade understanding. An array of studies in human patients and animal models has demonstrated that local signaling can generate strongly immunosuppressive microenvironments within tumors, and emerging evidence suggests that delivery of immunostimulatory molecules into tumors can have therapeutic effects. Nanoparticle formulations of these cargoes offer a promising way to maximize their delivery and to enhance the efficacy of checkpoint inhibitors. We developed a modular nanoparticle system capable of encapsulating an array of immunostimulatory oligonucleotides that, in some cases, greatly increase their potency to activate inflammatory signaling within immune cells in vitro. We hypothesized that these immunostimulatory nanoparticles could suppress tumor growth by activating similar signaling in vivo, and thereby also improve responsiveness to immune checkpoint inhibitor antibody therapies. We found that our engineered nanoparticles carrying a CpG DNA ligand of TLR9 can suppress tumor growth in several animal models of various cancers, resulting in an abscopal effect on distant tumors, and improving responsiveness to anti-CTLA4 treatment with combinatorial effects after intratumoral administration. Moreover, by incorporating tumor-homing peptides, immunostimulatory nucleotide-bearing nanoparticles facilitate antitumor efficacy after systemic intravenous (i.v.) administration.
The various types of cells that comprise the tumor mass all carry molecular markers that are not expressed or are expressed at much lower levels in normal cells. These differentially expressed ...molecules can be used as docking sites to concentrate drug conjugates and nanoparticles at tumors. Specific markers in tumor vessels are particularly well suited for targeting because molecules at the surface of blood vessels are readily accessible to circulating compounds. The increased concentration of a drug in the site of disease made possible by targeted delivery can be used to increase efficacy, reduce side effects, or achieve some of both. We review the recent advances in this delivery approach with a focus on the use of molecular markers of tumor vasculature as the primary target and nanoparticles as the delivery vehicle.
Diagnostics to accurately detect disease and monitor therapeutic response are essential for effective clinical management. Bioengineering, chemical biology, molecular biology, and computer science ...tools are converging to guide the design of diagnostics that leverage enzymatic activity to measure or produce biomarkers of disease. We review recent advances in the development of these 'activity-based diagnostics' (ABDx) and their application in infectious and noncommunicable diseases. We highlight efforts towards both molecular probes that respond to disease-specific catalytic activity to produce a diagnostic readout, as well as diagnostics that use enzymes as an engineered component of their sense-and-respond cascade. These technologies exemplify how integrating techniques from multiple disciplines with preclinical validation has enabled ABDx that may realize the goals of precision medicine.
Tools from an array of disciplines, such as bio-orthogonal chemistry, responsive nanomaterials, machine learning, synthetic gene circuits, and CRISPR/Cas systems, have enabled the development of engineered activity‐based diagnostics (ABDx).ABDx leverage enzymatic activity to measure or produce biomarkers of disease. Because of the substrate recognition and catalytic signal amplification properties of enzymes, ABDx afford the potential for highly specific, sensitive, and programmable diagnostics.ABDx have shown promise in preclinical settings for the detection of both noncommunicable (e.g., cancer) and infectious diseases, and have been applied for molecular sensing in vivo and for in vitro diagnostics run on ex vivo biospecimens.
The widespread view of bacteria as strictly pathogenic has given way to an appreciation of the prevalence of some beneficial microbes within the human body. It is perhaps inevitable that some ...bacteria would evolve to preferentially grow in environments that harbor disease and thus provide a natural platform for the development of engineered therapies. Such therapies could benefit from bacteria that are programmed to limit bacterial growth while continually producing and releasing cytotoxic agents in situ. Here we engineer a clinically relevant bacterium to lyse synchronously ata threshold population density and to release genetically encoded cargo. Following quorum lysis, a small number of surviving bacteria reseed the growing population, thus leading to pulsatile delivery cycles. We used microfluidic devices to characterize the engineered lysis strain and we demonstrate its potential as a drug delivery platform via co-culture with human cancer cells in vitro. Asa proof of principle, we tracked the bacterial population dynamics in ectopic syngeneic colorectal tumours in mice via a luminescent reporter. The lysis strain exhibits pulsatile population dynamics in vivo, with mean bacterial luminescence that remained two orders of magnitude lower than an unmodified strain. Finally, guided by previous findings that certain bacteria can enhance the efficacy of standard therapies, we orally administered the lysis strain alone or in combination with a clinical chemotherapeutic to a syngeneic mouse transplantation model of hepatic colorectal metastases. We found that the combination of both circuit-engineered bacteria and chemotherapy leads to a notable reduction of tumour activity along with a marked survival benefit over either therapy alone.Our approach establishes a methodology for leveraging the tools of synthetic biology to exploit the natural propensity for certain bacteria to colonize disease sites.
Ultrasmall gold nanoclusters (AuNCs) have emerged as agile probes for in vivo imaging, as they exhibit exceptional tumour accumulation and efficient renal clearance properties. However, their ...intrinsic catalytic activity, which can enable an increased detection sensitivity, has yet to be explored for in vivo sensing. By exploiting the peroxidase-mimicking activity of AuNCs and the precise nanometre-size filtration of the kidney, we designed multifunctional protease nanosensors that respond to disease microenvironments to produce a direct colorimetric urinary readout of the disease state in less than one hour. We monitored the catalytic activity of AuNCs in the collected urine of a mouse model of colorectal cancer in which tumour-bearing mice showed a 13-fold increase in colorimetric signal compared to healthy mice. The nanosensors were eliminated completely through hepatic and renal excretion within four weeks of injection with no evidence of toxicity. We envision that this modular approach will enable the rapid detection of a diverse range of diseases by exploiting their specific enzymatic signatures.
Cell and tissue engineering for liver disease Bhatia, Sangeeta N; Underhill, Gregory H; Zaret, Kenneth S ...
Science translational medicine,
07/2014, Letnik:
6, Številka:
245
Journal Article
Recenzirano
Odprti dostop
Despite the tremendous hurdles presented by the complexity of the liver's structure and function, advances in liver physiology, stem cell biology and reprogramming, and the engineering of tissues and ...devices are accelerating the development of cell-based therapies for treating liver disease and liver failure. This State of the Art Review discusses both the near- and long-term prospects for such cell-based therapies and the unique challenges for clinical translation.
Highlights • Nanoparticle designs and interactions in the body determine their individual behavior. • The collective behavior of nanoparticles can be exploited to improve their performance. • ...Bio-inspired mechanisms of cooperation include self-assembly and communication. • Systems approaches build on new nanomaterials, biological insight, and computation.
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