bims-limsir 2023-09-03 papers

Expert Opin Drug Deliv. 2023 Aug 29. 1-21

siRNA therapeutics: insights, challenges, remedies and future prospects.

Saba Khan, Urushi Rehman, Neha Parveen, Shobhit Kumar, Sanjula Baboota, Javed Ali.

INTRODUCTION: Among conventional and novel therapeutic approaches, the siRNA strategy stands out for treating disease by silencing the gene responsible for the corresponding disorder. Gene silencing is supposedly intended to target any disease-causing gene, and therefore, several attempts and investments were made to exploit siRNA gene therapy and advance it into clinical settings. Despite the remarkable beneficial prospects, the applicability of siRNA therapeutics is very challenging due to various pathophysiological barriers that hamper its target reach, which is the cytosol, and execution of gene silencing action.
AREAS COVERED: The present review provides insights into the field of siRNA therapeutics, significant in vivo hurdles that mitigate the target accessibility of siRNA, and remedies to overcome these siRNA delivery challenges. Nonetheless, the current review also highlights the on-going clinical trials and the regulatory aspects of siRNA modalities.
EXPERT OPINION: The siRNAs have the potential to reach previously untreated target sites and silence the concerned gene owing to their modification as polymeric or lipidic nanoparticles, conjugates, and the application of advanced drug delivery strategies. With such mounting research attempts to improve the delivery of siRNA to target tissue, we might shortly witness revolutionary therapeutic outcomes, new approvals, and clinical implications.

Keywords: Barriers; RNA interference; clinical trials; gene silencing; nanoparticles; siRNA-regulatory approval

DOI: https://doi.org/10.1080/17425247.2023.2251890

Nat Biomed Eng. 2023 Aug 31.

Multiplexed transcriptomic profiling of the fate of human CAR T cells in vivo via genetic barcoding with shielded small nucleotides.

Xiaoyin Lu, Shane M Lofgren, Yuehui Zhao, Pawel K Mazur.

The design of chimeric antigen receptor (CAR) T cells would benefit from knowledge of the fate of the cells in vivo. This requires the permanent labelling of CAR T cell products and their pooling in the same microenvironment. Here, we report a cell-barcoding method for the multiplexed longitudinal profiling of cells in vivo using single-cell RNA sequencing (scRNA-seq). The method, which we named shielded-small-nucleotide-based scRNA-seq (SSN-seq), is compatible with both 3' and 5' single-cell profiling, and enables the recording of cell identity, from cell infusion to isolation, by leveraging the ubiquitous Pol III U6 promoters to robustly express small-RNA barcodes modified with direct-capture sequences. By using SSN-seq to track the dynamics of the states of CAR T cells in a tumour-rechallenge mouse model of leukaemia, we found that a combination of cytokines and small-molecule inhibitors that are used in the ex vivo manufacturing of CAR T cells promotes the in vivo expansion of persistent populations of CD4+ memory T cells. By facilitating the probing of cell-state dynamics in vivo, SSN-seq may aid the development of adoptive cell therapies.

DOI: https://doi.org/10.1038/s41551-023-01085-3

Trends Immunol. 2023 Aug 29. pii: S1471-4906(23)00156-4. [Epub ahead of print]

CAR T cells ignite antitumor immunity.

Darya Alizadeh, Christine E Brown.

Broadening immune responses through antigen spreading remains the 'Holy Grail' of cancer immunotherapy. A study by Ma and colleagues reveals that vaccine boosting of chimeric antigen receptor (CAR)-T cells in mice promotes endogenous immunity and elicits antigen spread to eliminate antigenically heterogenous solid tumors through a mechanism crucially dependent on interferon (IFN)γ.

Keywords: CAR T cell; IFNgamma; antigen spreading; chimeric antigen receptor (CAR); myeloid cells; tumor heterogeneity; vaccine

DOI: https://doi.org/10.1016/j.it.2023.08.002

Nature. 2023 Aug 30.

Epitope editing enables targeted immunotherapy of acute myeloid leukaemia.

Gabriele Casirati, Andrea Cosentino, Adele Mucci, Mohammed Salah Mahmoud, Iratxe Ugarte Zabala, Jing Zeng, Scott B Ficarro, Denise Klatt, Christian Brendel, Alessandro Rambaldi, Jerome Ritz, Jarrod A Marto, Danilo Pellin, Daniel E Bauer, Scott A Armstrong, Pietro Genovese.

Despite the considerable efficacy observed when targeting a dispensable lineage antigen, such as CD19 in B cell acute lymphoblastic leukaemia1,2, the broader applicability of adoptive immunotherapies is hampered by the absence of tumour-restricted antigens3-5. Acute myeloid leukaemia immunotherapies target genes expressed by haematopoietic stem/progenitor cells (HSPCs) or differentiated myeloid cells, resulting in intolerable on-target/off-tumour toxicity. Here we show that epitope engineering of donor HSPCs used for bone marrow transplantation endows haematopoietic lineages with selective resistance to chimeric antigen receptor (CAR) T cells or monoclonal antibodies, without affecting protein function or regulation. This strategy enables the targeting of genes that are essential for leukaemia survival regardless of shared expression on HSPCs, reducing the risk of tumour immune escape. By performing epitope mapping and library screenings, we identified amino acid changes that abrogate the binding of therapeutic monoclonal antibodies targeting FLT3, CD123 and KIT, and optimized a base-editing approach to introduce them into CD34+ HSPCs, which retain long-term engraftment and multilineage differentiation ability. After CAR T cell treatment, we confirmed resistance of epitope-edited haematopoiesis and concomitant eradication of patient-derived acute myeloid leukaemia xenografts. Furthermore, we show that multiplex epitope engineering of HSPCs is feasible and enables more effective immunotherapies against multiple targets without incurring overlapping off-tumour toxicities. We envision that this approach will provide opportunities to treat relapsed/refractory acute myeloid leukaemia and enable safer non-genotoxic conditioning.

DOI: https://doi.org/10.1038/s41586-023-06496-5