Biology subjects

Mastrokalou, C.

Publications and source records attributed to Mastrokalou, C..

3 recordsLinked to original sources

bioRxiv2026

Comparative Single-Cell Profiling of CRISPR Knockout and Interference Defines Modality-Specific Strengths in Functional Genomics

Pooled CRISPR screens coupled with single-cell RNA sequencing enable high-throughput functional interrogation of gene regulatory networks, yet systematic comparisons of CRISPR knockout (CRISPRko) and CRISPR interference (CRISPRi) remain limited. We established a single-cell CRISPRko workflow and benchmarked it against CRISPRi using 87 sgRNAs targeting 29 unfolded protein response genes. CRISPRko generated transcriptional phenotypes are highly concordant with CRISPRi, and induced comparable pathway-level responses. While CRISPRi allows direct assessment of target gene repression, CRISPRko provides an effective complementary approach for complete loss-of-function studies, expanding the toolkit for single-cell functional genomics.

genomics↗

bioRxiv2026

Scarless conditional sgRNAs via endogenous mascRNA processing enable rapid and temporally controlled genome editing

Precise temporal control of gene editing is essential for studying dynamic biological processes, interrogating essential gene function, and improving the interpretability of pooled perturbation screens. Cre-dependent single guide RNA (sgRNA) switches provide temporal regulation by coupling guide activation to site-specific recombination, but existing designs retain a loxP-derived 5' sequence (scar) on the mature sgRNA that can impair guide function. We developed a scarless conditional sgRNA platform that combines Cre-loxP recombination with endogenous RNA processing to restore the native sgRNA architecture following induction. A MALAT1-associated small cytoplasmic RNA (mascRNA) module was positioned upstream of the guide sequence such that, after Cre-mediated recombination, cellular RNase P and RNase Z remove the residual loxP-derived overhang, generating a mature sgRNA with an authentic 5' terminus. Using guides targeting endogenous cell-surface marker genes, the scarless design maintained stringent OFF-state control while improving ON-state editing performance compared with a conventional Cre-activated sgRNA switch, resulting in faster editing kinetics, greater perturbation penetrance, and more consistent editing efficiency. This modular strategy provides a simple approach for conditional CRISPR genome editing that preserves guide integrity and should be readily adaptable to time-resolved functional genomics and pooled screening applications.

cell biology↗

bioRxiv2022

Genomic characteristics and clinical significance of CD56+ Circulating Tumor Cells in Small Cell Lung Carcinoma

IntroductionCirculating Tumor Cells (CTC) have been studied in various solid tumors but clinical utility of CTC in Small Cell Lung Cancer (SCLC) remains unclear. The aim of the CTC-CPC study was to develop an EpCAM-independent CTC isolation method allowing isolation of a broader range of living CTC from SCLC and decipher their genomic and biological characteristics. Patients and methodsCTC-CPC is a monocentric prospective non-interventional study including treatment-naive newly diagnosed SCLC. CD56+CTC were isolated from whole blood samples, at diagnosis and relapse after first-line treatment and submitted to Whole-exome-sequencing (WES). ResultsPhenotypic study confirms tumor lineage and tumorigenic properties of isolated cells for the 4 patients analyzed with WES. WES of CD56+CTC and matched tumor biopsy reveal genomic alteration frequently impaired in SCLC. At diagnosis CD56+CTC were characterized by a high mutation load, a distinct mutational profile and a unique genomic, compared to match tumors biopsies. In addition to classical pathways altered in SCLC, we found new biological processes specifically affected in CD56+CTC at diagnosis. High numeration of CD56+CTC (>7/ml) at diagnosis was associated with ES-SCLC. Comparing CD56+CTC isolated at diagnosis and relapse, we identify differentially altered oncogenic pathways (e.g. DLL3 or MAPK pathway). ConclusionsWe report a versatile method of CD56+CTC detection in SCLC. Numeration of CD56+CTC at diagnosis is correlated with disease extension. Isolated CD56+CTC are tumorigenic and a distinct mutational profile. We report a minimal gene set as a unique signature of CD56+CTC and identify new affected biological pathways enriched in EpCAM-independent isolated CTC in SCLC.

cancer biology↗