Strong immune responses and protection of PcrV and OprF-I mRNA vaccine candidates against Pseudomonas aeruginosa.

Pseudomonas aeruginosa (PA) is a leading cause of hospital-acquired and ventilator-associated pneumonia. The multidrug-resistance (MDR) rate of PA is increasing making the management of PA a global challenge. Messenger RNA (mRNA) vaccines represent the most promising alternative to conventional vaccines and are widely studied for viral infection and cancer immunotherapy while rarely studied for bacterial infections. In this study, two mRNA vaccines encoding PcrV- the key component of the type III secretion system in Pseudomonas and the fusion protein OprF-I comprising outer membrane proteins OprF and OprI were constructed. The mice were immunized with either one of these mRNA vaccines or with the combination of both. Additionally, mice were vaccinated with PcrV, OprF, or the combination of these two proteins. Immunization with either mRNA-PcrV or mRNA-OprF-I elicited a Th1/Th2 mixed or slighted Th1-biased immune response, conferred broad protection, and reduced bacterial burden and inflammation in burn and systemic infection models. mRNA-PcrV induced significantly stronger antigen-specific humoral and cellular immune responses and higher survival rate compared with the OprF-I after challenging with all the PA strains tested. The combined mRNA vaccine demonstrated the best survival rate. Moreover, the mRNA vaccines showed the superiority over protein vaccines. These results suggest that mRNA-PcrV as well as the mixture of mRNA-PcrV and mRNA-OprF-I are promising vaccine candidates for the prevention of PA infection.

Identification of Tumor Antigens and Design of mRNA Vaccine for Colorectal Cancer Based on the Immune Subtype.

mRNA vaccines have become a promising alternative to conventional cancer immunotherapy approaches. However, its application on colorectal cancer (CRC) remains poorly understood. We herein identified potential antigens for designing an effective mRNA vaccine, further to build an immune landscape for the accurate selection of patients for mRNA vaccine therapy. Raw transcriptome data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were retrieved. Consensus clustering algorithm was applied to divide the CRC samples into four immune subtypes. Immunogenomics analysis was further integrated to characterize the immune microenvironment of each immune subtype. Six tumor antigens were found to be associated with poor prognosis and infiltration of antigen-presenting cells (APCs) in CRC patients. Furthermore, each of the immune subtypes showed differential cellular and molecular features. The IS2 and IS4 exhibited significantly improved survival and higher immune cell infiltration compared with IS1 and IS3. Immune checkpoint molecules and human leukocyte antigen also showed significant differential expression in four immune subtypes. Moreover, we performed graph structure learning-based dimensionality reduction to visualize the immune landscape of CRC. Our results revealed a complex immune landscape that may provide directions for mRNA vaccine treatment of CRC and define appropriate vaccination patients.

In Situ Formation of Nanotheranostics to Overcome the Blood-Brain Barrier and Enhance Treatment of Orthotopic Glioma.

Glioblastoma is one of the most lethal cancers and needs effective therapeutics. The development of coordination-driven metal-organic nanoassemblies, which can cross the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) and have multiple desired functions, may provide a promising solution to this issue. Here, we report an in situ assembled nanoplatform based on RGD peptide-modified bisulfite-zincII-dipicolylamine-Arg-Gly-Asp (Bis(DPA-Zn)-RGD) and ultrasmall Au-ICG nanoparticles. Attributed to its positive charges and neovascular targeting properties, Bis(DPA-Zn)-RGD can be selectively delivered to the tumor site, and then assembled in situ into large nanoclusters with subsequently administered Au-ICG nanoparticles. Au nanoparticles with ultrasmall size (∼7 nm) can successfully cross the BBB. The obtained nanoclusters exhibit strong near-infrared-red (NIR) absorption and an enhanced tumor retention effect, enabling precise orthotopic fluorescence/photoacoustic imaging. With the aid of image guidance, the photothermal effect of the nanoclusters is observed to suppress tumor progression with the inhibition efficiency reaching up to 93.9%. Meanwhile, no photothermal damage can be found for normal brain tissues. These results, herein, suggest a feasible nanotheranostic agent with the ability to overcome the BBB and BBTB for imaging and therapy of orthotopic brain tumors.

Oxidative stress-driven DR5 upregulation restores TRAIL/Apo2L sensitivity induced by iron oxide nanoparticles in colorectal cancer.

There exists an emergency clinical demand to overcome TRAIL/Apo2L (tumor necrosis factor-related apoptosis-inducing ligand) resistance, which is a major obstacle attributed to insufficient level or mutation of TRAIL receptors. Here, we developed an iron oxide cluster-based nanoplatform for both sensitization and MR image-guided evaluation to improve TRAIL/Apo2L efficacy in colorectal cancer, which has an inadequate response to TRAIL/Apo2L or chemotherapy. Specifically, NanoTRAIL (TRAIL/Apo2L-iron oxide nanoparticles) generated ROS (reactive oxygen species)-triggered JNK (c-Jun N-terminal kinase) activation and induced subsequent autophagy-assisted DR5 upregulation, resulting in a significant enhanced antitumor efficacy of TRAIL/Apo2L, which confirmed in both TRAIL-resistant HT-29, intermediately resistant SW-480 and sensitive HCT-116 cells. Furthermore, in a subcutaneous colorectal cancer mouse model, the in vivo tumor retention of NanoTRAIL can be demonstrated by MR T2 weighted contrast imaging, and NanoTRAIL significantly suppressed tumor growth and prolonged the survival time without observable adverse effects compared with control and TRAIL/Apo2L monotherapy. Importantly, in the study of colorectal cancer patient-derived xenograft models, we found that the NanoTRAIL treatment could significantly improve the survival outcome with consistent ROS-dependent autophagy-assisted DR5 upregulation and tumor apoptosis. Our results describe a transformative design that can be applied clinically to sensitize Apo2L/TRAIL-resistant patients using FDA-approved iron oxide nanoparticles.