Biology subjects

Foronda, M.

Publications and source records attributed to Foronda, M..

7 recordsLinked to original sources

bioRxiv2025

A potent and selective TNKS2 inhibitor for tumor-selective WNT suppression

Hyperactive WNT signaling is a potent cancer driver, but clinical translation of WNT inhibitors has been hampered by on-target toxicities. WNT signaling can be constrained through inhibition of the PARP family enzymes Tankyrase 1 (TNKS1) and Tankyrase 2 (TNKS2), however, existing TNKS inhibitors suppress WNT signaling in both tumor and healthy tissues. In this study, we show that the loss of chromosome 8p that occurs in approximately half of advanced epithelial malignancies, creates a collateral vulnerability that enables tumor-selective inhibition of Tankyrase activity. 8p loss depletes expression of TNKS1 and creates a tumor-specific dependency on the functionally redundant TNKS2 protein. Through structure-guided drug design, we identify a first-in-class TNKS2-selective inhibitor that can drive selective WNT inhibition in TNKS1-deficient oncogenic cell and organoid models. This work demonstrates a targetable vulnerability in multiple cancer types, providing a new approach to potent and selective WNT-targeted therapies.

cancer biology↗

bioRxiv2022

Rapid generation of precision preclinical cancer models using regulatable in vivo base editing

Single nucleotide variants (SNVs) comprise the majority of cancer-associated genetic changes and can have diverse effects on protein function. Despite a comprehensive catalogue of SNVs across human cancers, little is known about their impact on tumor initiation and progression. To enable the functional interrogation of cancer-associated SNVs, we developed a murine system for temporal and regulatable in vivo cytosine base editing (iBE). The iBE mice show robust, doxycycline-dependent expression across a broad range of tissues with no evidence of DNA or RNA off-target effects. Transient iBE induction drives efficient creation of individual or multiple SNVs in intestinal, lung, and pancreatic organoids, while temporal iBE regulation allows controlled sequential genome editing. Moreover, in situ delivery of plasmid-based or synthetic sgRNAs to target tissues facilitates the simple and rapid generation of pre-clinical cancer models. Overall, iBE is a powerful in vivo platform to define and interrogate the genetic drivers of cancer.

cancer biology↗

bioRxiv2022

Obesity promotes breast epithelium DNA damage in BRCA mutation carriers

Obesity is an established risk factor for breast cancer among women in the general population after menopause. Whether elevated bodyweight is a risk factor for women with a germline mutation in BRCA1 or BRCA2 is less clear due to inconsistent findings from epidemiological studies and lack of mechanistic studies in this population. Here, we show that DNA damage in normal breast epithelium of BRCA mutation carriers is positively correlated with body mass index and with biomarkers of metabolic dysfunction. Additionally, RNA-sequencing reveals significant obesity-associated alterations to the breast adipose microenvironment of BRCA mutation carriers, including activation of estrogen biosynthesis, which impacts neighboring breast epithelial cells. We found that blockade of estrogen biosynthesis or estrogen receptor activity decreases DNA damage, whereas treatment with leptin or insulin increases DNA damage in BRCA heterozygous epithelial cells. Furthermore, we show that increased adiposity is associated with mammary gland DNA damage and increased penetrance of mammary tumors in Brca1+/- mice. Overall, our results provide mechanistic evidence in support of a link between bodyweight and breast cancer development in BRCA mutation carriers and suggests that maintaining a healthy bodyweight or pharmacologically targeting estrogen or metabolic dysfunction may reduce the risk of breast cancer in this population. One Sentence SummaryElevated bodyweight is positively associated with DNA damage in breast epithelium of BRCA mutation carriers

cancer biology↗

bioRxiv2019

GO: A functional reporter system to identify and enrich base editing activity

Base editing (BE) is a powerful tool for engineering single nucleotide variants (SNVs) and has been used to create targeted mutations in cell lines, organoids, and animal models. Recent development of new BE enzymes has provided an extensive toolkit for genome modification; however, identifying and isolating edited cells for analysis has proven challenging. Here we report a "Gene On" (GO) reporter system that indicates precise cytosine or adenine base editing in situ with high sensitivity and specificity. We test GO using an activatable GFP and use it to measure the kinetics, efficiency, and PAM specificity of a range of new BE variants. Further, GO is flexible and can be easily adapted to induce expression of numerous genetically encoded markers, antibiotic resistance genes, or enzymes such as Cre recombinase. With these tools, GO can be exploited to functionally link BE events at endogenous genomic loci to cellular enzymatic activities in human and mouse cell lines and organoids. Thus, GO provides a powerful approach to increase the practicality and feasibility of implementing CRISPR BE in biomedical research.

bioengineering↗

bioRxiv2019

A machine learning approach predicts essential genes and pharmacological targets in cancer

Loss-of-function (LoF) screenings have the potential to reveal novel cancer-specific vulnerabilities, prioritize drug treatments, and inform precision medicine therapeutics. These screenings were traditionally done using shRNAs, but with the recent emergence of CRISPR technology there has been a shift in methodology. However, recent analyses have found large inconsistencies between CRISPR and shRNA essentiality results. Here, we examined the DepMap project, the largest cancer LoF effort undertaken to date, and find a lack of correlation between CRISPR and shRNA LoF results; we further characterized differences between genes found to be essential by either platform. We then introduce ECLIPSE, a machine learning approach, which combines genomic, cell line, and experimental design features to predict essential genes and platform specific essential genes in specific cancer cell lines. We applied ECLIPSE to known drug targets and found that our approach strongly differentiated drugs approved for cancer versus those that have not, and can thus be leveraged to identify potential cancer repurposing opportunities. Overall, ECLIPSE allows for a more comprehensive analysis of gene essentiality and drug development; which neither platform can achieve alone.

cancer biology↗

bioRxiv2019

Tankyrase inhibition sensitizes cells to CDK4 blockade

Tankyrase (TNKS) 1/2 are positive regulators of WNT signaling by controlling the activity of the {beta}-catenin destruction complex. TNKS inhibitors provide an opportunity to suppress hyperactive WNT signaling in tumors, however, they have shown limited anti-proliferative activity as a monotherapy in human cancer cell lines. Here we perform a kinome-focused CRISPR screen to identify potential effective drug combinations with TNKS inhibition. We show that the loss of CDK4, but not CDK6, synergizes with TNKS1/2 blockade to drive G1 cell cycle arrest and senescence. Through precise modelling of cancer-associated mutations using cytidine base editors, we show that this therapeutic approach is absolutely dependent on suppression of canonical WNT signaling by TNKS inhibitors and is effective in cells from multiple epithelial cancer types. Together, our results suggest that combined WNT and CDK4 inhibition might provide a potential therapeutic strategy for difficult-to-treat epithelial tumors.

cancer biology↗

bioRxiv2018

An optimized toolkit for precision base editing

CRISPR base editing is a potentially powerful technology that enables the creation of genetic mutations with single base pair resolution. By re-engineering both DNA and protein sequences, we developed a collection of constitutive and inducible base editing vector systems that dramatically improve the ease and efficiency by which single nucleotide variants can be created. This new toolkit is effective in a wide range of model systems, and provides a means for efficient in vivo somatic base editing.

bioengineering↗