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.

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.

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Targeted therapies against cancer can relieve symptoms and induce remission; however, they often present limited duration of disease control, cause side effects, and may induce acquired resistance. Therefore, there is great motivation to develop a unique delivery system, targeted to the tumor, in which several active entities can be combined, the therapeutic index can be increased by reducing systemic exposure, and their synergistic activity can be enhanced. To meet these goals, the biocompatible and biodegradable poly(α,l‐glutamic acid) (PGA) is chosen as a nanocarrier that facilitates extravasation‐dependent tumor targeting delivery. The RAS/RAF/MEK/ERK pathway when aberrantly activated in melanoma, can lead to uncontrolled cell proliferation, induced invasion, and reduced apoptosis. Here, two drugs targeting this pathway are selected: a MEK1/2 inhibitor (selumetinib, SLM) and a modified BRAF inhibitor (modified dabrafenib, mDBF) that exhibit synergism in vitro. The combination of PGA conjugated to SLM and mDBF (PGA–SLM–mDBF) is synthesized and characterized. PGA–SLM–mDBF inhibits the proliferation of melanoma cells and decreases their migratory and sprouting abilities without inducing a hemolytic effect. Moreover, it exhibits superior antitumor activity in a mouse model of primary melanoma and prolonged survival at a lower dose than the free drugs.