Biology subjects

Shamloo, S.

Publications and source records attributed to Shamloo, S..

3 recordsLinked to original sources

bioRxiv2024

RNA Binding of GAPDH Controls Transcript Stability and Protein Translation in Acute Myeloid Leukemia

Dysregulation of RNA binding proteins (RBPs) is a hallmark in cancerous cells. In acute myeloid leukemia (AML) RBPs are key regulators of tumor proliferation. While classical RBPs have defined RNA binding domains, RNA recognition and function in AML by non-canonical RBPs (ncRBPs) remain unclear. Given the inherent complexity of targeting AML broadly, our goal was to uncover potential ncRBP candidates critical for AML survival using a CRISPR/Cas-based screening. We identified the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a pro-proliferative factor in AML cells. Based on cross-linking and immunoprecipitation (CLIP), we are defining the global targetome, detecting novel RNA targets mainly located within 5UTRs, including GAPDH, RPL13a, and PKM. The knockdown of GAPDH unveiled genetic pathways related to ribosome biogenesis, translation initiation, and regulation. Moreover, we demonstrated a stabilizing effect through GAPDH binding to target transcripts including its own mRNA. The present findings provide new insights on the RNA functions and characteristics of GAPDH in AML.

cancer biology↗

bioRxiv2024

Dual CRISPR-Interference Strategy for Targeting Synthetic Lethal Interactions between Non-Coding RNAs in Cancer Cells

Long non-coding RNAs (lncRNAs) represent a vast and functionally diverse class of RNA molecules, with over 100,000 predicted in the human genome. Although lncRNAs are less conserved across species compared to protein-coding genes, they play critical roles in gene regulation, chromatin interactions, and cancer progression. Their involvement in cancer make them promising therapeutic targets. CRISPR interference (CRISPRi), utilizing catalytically inactive Cas9 fused with a transcriptional repressor such as KRAB-MeCP2, offers a precise method for targeting nuclear lncRNAs and assessing their functions. This study introduces a dual CRISPRi system using orthogonal CRISPRi technologies from Staphylococcus aureus and Streptococcus pyogenes dCas9-KRAB, optimized for combinatorial targeting of lncRNAs in human melanoma cells. The protocol facilitates combinatorial gene knockdown or synthetic lethal screening of lncRNA pairs, providing a novel tool for cancer research. By exploring synthetic lethality between lncRNAs, this approach can help identify lncRNA interactions critical for cancer cell survival, offering new therapeutic strategies. The dual systems functionality is demonstrated, highlighting its potential in identifying critical cancer-specific lncRNA interactions. SUMMARYThis study presents a dual CRISPRi system targeting long non-coding RNAs in melanoma cells. It enables combinatorial gene knockdown and synthetic lethal screening, identifying cancerspecific lncRNA interactions for potential therapeutic strategies.

cell biology↗

bioRxiv2024

CRISPR-inhibition screen for lncRNAs linked to melanoma growth and metastasis

Melanoma being one of the most common and deadliest skin cancers, has been rising since the past decade. Patients at advanced stages of the disease have very poor prognoses, as opposed to at the earlier stages. Nowadays the standard-of-care of advanced melanoma is resection followed by immune checkpoint inhibition based immunotherapy. However, a substantial proportion of patients either do not respond or develop resistances. This underscores a need for novel approaches and therapeutic targets as well as a better understanding of the mechanisms of melanoma pathogenesis. Long non-coding RNAs (lncRNAs) comprise a poorly characterized class of functional players and promising targets in promoting malignancy. Certain lncRNAs have been identified to play integral roles in melanoma progression and drug resistances, however systematic screens to uncover novel functional lncRNAs are scarce. Here, we profile differentially expressed lncRNAs in patient derived short-term metastatic cultures and BRAF-MEK-inhibition resistant cells. We conduct a focused growth-related CRISPR-inhibition screen of overexpressed lncRNAs, validate and functionally characterize lncRNA hits with respect to cellular growth, invasive capacities and apoptosis in vitro as well as the transcriptomic impact of our lead candidate the novel lncRNA XLOC_030781. In sum, we extend the current knowledge of ncRNAs and their potential relevance on melanoma. SignificancePreviously considered as transcriptional noise, lncRNAs have emerged as novel players in regulating many cellular aspects in health and disease including melanoma. However, the number and as well as the extent of functional significance of most lncRNAs remains elusive. We provide a comprehensive strategy to identify functionally relevant lncRNAs in melanoma by combining expression profiling with CRISPR-inhibition growths screens lowering the experimental effort. We also provide a larger resource of differentially expressed lncRNAs with potential implications in melanoma growth and invasion. Our results broaden the characterized of lncRNAs as potential targets for future therapeutic applications.

cancer biology↗