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Generation of a STRAIGHT-IN Dual AAVS1 hiPSC line with orthogonal landing pads for versatile DNA payload integration.

The STRAIGHT-IN platform is designed for facile genomic integration of DNA payloads into human induced pluripotent stem cells (hiPSCs) that contain a pre-inserted landing pad (LP). Here, we expanded the versatility of STRAIGHT-IN by introducing an additional, orthogonal LP into the unmodified allele of the safe harbor locus AAVS1. Specifically, we targeted the hiPSC line LUMC0099iCTRL04_AAVS1-bxb-v2 (hPSCreg LUMCi004-A-1), which already carried one LP. The resulting STRAIGHT-IN AAVS1 Dual line can integrate two independent DNA payloads in parallel, expanding the applicability of the platform for complex genomic engineering applications.

Humans

Engineering STRAIGHT-IN single and dual lines in the male iPS11 parental line for programmable DNA integration.

STRAIGHT-IN is a genome engineering platform that enables precise integration of DNA payloads into mammalian genomes, including hiPSCs. In this study, we generated three hiPSC acceptor lines containing either one (single) or two (dual) landing pads. These landing pads support efficient, seamless integration of DNA cargos with single-copy control and a near-scarless genomic footprint. All landing pads were targeted to the CLYBL genomic safe harbor locus in the male hiPSC line iPS11. The resulting acceptor lines offer a versatile resource for the controlled genomic integration of diverse transgenes, making them broadly applicable to a wide range of applications.

Humans

Cre-loaded integrase-defective lentiviral vectors for targeted cassette exchange in CHO cells.

Genome-modifying enzymes, such as recombinases and CRISPR-associated nucleases, enable targeted gene insertion when delivered transiently to minimize off-target effects. Precise genome engineering requires controlled enzyme activity, as well as efficient donor DNA transfer. Integrase-defective lentiviral vectors (IDLVs) provide a promising platform for transient episomal DNA transfer; however, their integration efficiency depends on complementary genome-targeting strategies. Here, we engineered Cre-loaded IDLVs (Cre-IDLVs) that co-package lentiviral vector genomes together with bioactive Cre recombinase. Cre was inserted into the Gag region of an integrase-defective gag-pol construct, allowing for efficient encapsidation and protease-mediated release during virion maturation without compromising the viral titer. The resulting particles carried donor cassettes flanked by heterospecific loxP sites. When applied to CHO founder cells harboring compatible genomic loxP landing pads, Cre-IDLVs efficiently mediated recombination-mediated cassette exchange, producing the highest number of G418-resistant colonies among the plasmid ratios tested. Genomic PCR and sequencing confirmed precise locus-specific insertion without detectable random integration in the analyzed clones. These findings establish Cre-IDLVs as a streamlined dual-delivery platform that couples transient recombinase activity with episomal donor DNA transfer. This hybrid lentiviral strategy provides a programmable approach for controlled and site-specific genome modification in mammalian cells.

Integrases

BOGO: A Proteome-Wide Gene Overexpression Platform for Discovering Rational Cancer Combination Therapies.

Cancer drug resistance remains a major barrier to durable treatment success, often leading to relapse despite advances in precision oncology. While combination therapies are being increasingly investigated, such as chemotherapy with small molecule inhibitors, predicting drug response and identifying rational drug combinations based on resistance mechanisms remain major challenges. Therefore, a proteome-wide, single-gene overexpression screening platform is essential for guiding rational therapy selection. Here, we present BOGO (Bxb1-landing pad human ORFeome-integrated system for a proteome-wide Gene Overexpression), a robust, scalable, and reproducible screening platform that enables single-copy, site-specific integration and overexpression of ~19,000 human open across cancer cell models. Using BOGO, we identified drug-specific response drivers for 16 chemotherapeutic agents and integrated clinical datasets to uncover proliferation and resistance-associated genes with prognostic potential. Drug response similarity networks revealed both shared and unique mechanisms, highlighting key pathways such as autophagy, apoptosis, and Wnt signaling, and notable resistance-associated genes including BCL2, POLD2, and TRADD. In particular, we proposed a synergistic combination of the BCL2 family inhibitor ABT-263 (Navitoclax®) and the DNA analog TAS-102 (Lonsurf®), which revealed that lysosomal modulation is a key mechanism driving DNA analog resistance. This combination therapy selectively enhanced cytotoxicity in colorectal and pancreatic cancer cells in vitro, and demonstrated therapeutic benefit in vivo in both cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models. Together, these findings establish BOGO as a powerful gene overexpression perturbation platform for systematically identifying chemoresistance and chemosensitization drivers, and for discovering rational combination therapies. Its scalability and reproducibility position BOGO as a broadly applicable tool for functional genomics and therapeutic discovery beyond cancer resistance.

Journal Article

Site-specific gene integration by recombinase-mediated cassette exchange in anhydrobiotic Pv11 cells.

Pv11 cells, derived from Polypedilum vanderplanki, uniquely tolerate complete desiccation (anhydrobiosis). Although a CRISPR/Cas9-based precise integration method (CRIS-PITCh) has been developed for Pv11 cells, a CRISPR-free strategy that fixes both the genomic locus and transgene copy number has not yet been established. Here, we implement recombinase-mediated cassette exchange (RMCE) in Pv11 cells and generate master cell lines that retain anhydrobiosis following genetic engineering. We first evaluated the activity of multiple site-specific recombinases in Pv11 cells using a transient two-plasmid reporter assay. Flp, Cre, and Bxb1 recombinases all excised a test cassette and activated a green fluorescent protein (GFP) reporter, whereas phiC31 integrase mediated recombination at the DNA sequence level but did not induce reporter expression under our construct configuration. To enable genomic RMCE, we inserted an FRT/FRT3-landing pad (LP) into a previously identified genomic safe-harbor locus using CRIS-PITCh and isolated clonal master cell lines by single-cell sorting. Using the established master line, Flp-based RMCE achieved site-specific cassette exchange at the LP, producing HaloTag fluorescence and drug resistance upon successful exchange. In addition, the expected post-exchange sequence was confirmed by sequencing. We further established an all-in-one RMCE vector combining the Flp recombinase and donor cassette on a single plasmid. Together, these results demonstrate locus-defined, single-copy transgene integration in anhydrobiotic Pv11 cells via RMCE and provide a standardized, CRISPR-free workflow for routine genetic manipulation in this unique cell line. This workflow facilitates both fundamental research and applied biotechnological applications using desiccation-tolerant cells.

Anhydrobiosis

Implementation of a pneumatic-tube system for transport of blood specimens.

Whole-blood specimens were transported through an installed 485-meter pneumatic-tube system dedicated to blood transport. The system featured constant-speed, low-carrier-velocity travel (3.6 m/sec) with controlled deceleration prior to arrival at its destination. Inserts were designed with ample use of padding to minimize agitation during transport and landing. Serum potassium, hemoglobin, and lactate dehydrogenase activity and whole-blood pH, PCO2, and PO2 were not altered in freshly drawn blood transported in this system. Partial filling or heparinization of the specimen containers did not alter the results. When specimens were allowed to clot prior to pneumatic-tube transport, significantly higher levels of serum lactate dehydrogenase were obtained. This study demonstrates that transport of whole-blood specimens by pneumatic tube without damage to blood components is feasible.

Air