Chemiluminescent luminophores are considered as one of the most sensitive families of probes for detection and imaging applications. Due to their high signal-to-noise ratios, luminophores with near-infrared (NIR) emission are particularly important for in vivo use. In addition, light with such long wavelength has significantly greater capability for penetration through organic tissue. So far, only a few reports have described the use of chemiluminescence systems for in vivo imaging. Such systems are always based on an energy-transfer process from a chemiluminescent precursor to a nearby emissive fluorescent dye. Here, we describe the development of the first chemiluminescent luminophores with a direct mode of NIR light emission that are suitable for use under physiological conditions. Our strategy is based on incorporation of a substituent with an extended π-electron system on the excited species obtained during the chemiexcitation pathway of Schaap's adamantylidene-dioxetane probe. In this manner, we designed and synthesized two new luminophores with direct light emission wavelength in the NIR region. Masking of the luminophores with analyte-responsive groups has resulted in turn-ON probes for detection and imaging of β-galactosidase and hydrogen peroxide. The probes' ability to image their corresponding analyte/enzyme was effectively demonstrated in vitro for β-galactosidase activity and in vivo in a mouse model of inflammation. We anticipate that our strategy for obtaining NIR luminophores will open new doors for further exploration of complex biomolecular systems using non-invasive intravital chemiluminescence imaging techniques.

Singlet oxygen is among the reactive oxygen species (ROS) with the shortest life-times in aqueous media because of its extremely high reactivity. Therefore, designing sensors for detection of O is perhaps one of the most challenging tasks in the field of molecular probes. Herein, we report a highly selective and sensitive chemiluminescence probe (SOCL-CPP) for the detection of O in living cells. The probe reacts with O to form a dioxetane that spontaneously decomposes under physiological conditions through a chemiexcitation pathway to emit green light with extraordinary intensity. SOCL-CPP demonstrated promising ability to detect and image intracellular O produced by a photosensitizer in HeLa cells during photodynamic therapy (PDT) mode of action. Our findings make SOCL-CPP the most effective known chemiluminescence probe for the detection of O . We anticipate that our chemiluminescence probe for O imaging would be useful in PDT-related applications and for monitoring O endogenously generated by cells in response to different stimuli.

The heterogeneity of pancreatic ductal adenocarcinoma (PDAC) suggests that successful treatment might rely on simultaneous targeting of multiple genes, which can be achieved by RNA interference-based therapeutic strategies. Here we show a potent combination of microRNA and siRNA delivered by an efficient nanocarrier to PDAC tumors. Using proteomic-microRNA profiles and survival data of PDAC patients from TCGA, we found a novel signature for prolonged survival. Accordingly, we used a microRNA-mimic to increase miR-34a together with siRNA to silence PLK1 oncogene. For in vivo dual-targeting of this combination, we developed a biodegradable amphiphilic polyglutamate amine polymeric nanocarrier (APA). APA-miRNA–siRNA polyplexes systemically administered to orthotopically inoculated PDAC-bearing mice showed no toxicity and accumulated at the tumor, resulting in an enhanced antitumor effect due to inhibition of MYC oncogene, a common target of both miR-34a and PLK1. Taken together, our findings warrant this unique combined polyplex’s potential as a novel nanotherapeutic for PDAC.

Introns are key regulators of eukaryotic gene expression and present a potentially powerful tool for the design of synthetic eukaryotic gene expression systems. However, intronic control over gene expression is governed by a multitude of complex, incompletely understood, regulatory mechanisms. Despite this lack of detailed mechanistic understanding, here we show how a relatively simple model enables accurate and predictable tuning of synthetic gene expression system in yeast using several predictive intron features such as transcript folding and sequence motifs. Using only natural Saccharomyces cerevisiae introns as regulators, we demonstrate fine and accurate control over gene expression spanning a 100 fold expression range. These results broaden the engineering toolbox of synthetic gene expression systems and provide a framework in which precise and robust tuning of gene expression is accomplished.

The majority of theranostic prodrugs reported so far relay information through a fluorogenic response generated upon release of the active chemotherapeutic agent. A chemiluminescence detection mode offers significant advantages over fluorescence, mainly due to the superior signal-to-noise ratio of chemiluminescence. Here we report the design and synthesis of the first theranostic prodrug monitored by a chemiluminescence diagnostic mode. As a representative model, we prepared a prodrug from the chemotherapeutic monomethyl auristatin E, which was modified for activation by β-galactosidase. The activation of the prodrug in the presence of β-galactosidase is accompanied by emission of a green photon. Light emission intensities, which increase with increasing concentration of the prodrug, were linearly correlated with a decrease in the viability of a human cell line that stably expresses β-galactosidase. We obtained sharp intravital chemiluminescent images of endogenous enzymatic activity in β-galactosidase-overexpressing tumor-bearing mice. The exceptional sensitivity achieved with the chemiluminescence diagnostic mode should allow the exploitation of theranostic prodrugs for personalized cancer treatment.

Complete tumor removal during surgery has a great impact on patient survival. To that end, the surgeon should detect the tumor, remove it and validate that there are no residual cancer cells left behind. Residual cells at the incision margin of the tissue removed during surgery are associated with tumor recurrence and poor prognosis for the patient. In order to remove the tumor tissue completely with minimal collateral damage to healthy tissue, there is a need for diagnostic tools that will differentiate between the tumor and its normal surroundings.Methods: We designed, synthesized and characterized three novel polymeric Turn-ON probes that will be activated at the tumor site by cysteine cathepsins that are highly expressed in multiple tumor types. Utilizing orthotopic breast cancer and melanoma models, which spontaneously metastasize to the brain, we studied the kinetics of our polymeric Turn-ON nano-probes.Results: To date, numerous low molecular weight cathepsin-sensitive substrates have been reported, however, most of them suffer from rapid clearance and reduced signal shortly after administration. Here, we show an improved tumor-to-background ratio upon activation of our Turn-ON probes by cathepsins. The signal obtained from the tumor was stable and delineated the tumor boundaries during the whole surgical procedure, enabling accurate resection.Conclusions: Our findings show that the control groups of tumor-bearing mice, which underwent either standard surgery under white light only or under the fluorescence guidance of the commercially-available imaging agents ProSense® 680 or 5-aminolevulinic acid (5-ALA), survived for less time and suffered from tumor recurrence earlier than the group that underwent image-guided surgery (IGS) using our Turn-ON probes. Our "smart" polymeric probes can potentially assist surgeons' decision in real-time during surgery regarding the tumor margins needed to be removed, leading to improved patient outcome.

No abstract

No abstract