Biology subjects

Moasser, M. M.

Publications and source records attributed to Moasser, M. M..

3 recordsLinked to original sources

bioRxiv2025

Metabolic Alterations driven by PFKFB3 upregulation confer Resistance to Trastuzumab in HER2-Positive Breast Cancer.

AimsResistance to anti-HER2 therapies, particularly trastuzumab, remains a major obstacle in the treatment of HER2-positive (HER2+) breast cancer. This study aims to uncover novel mechanisms driving trastuzumab resistance with a focus on the immune component, key mediator of trastuzumab efficacy. MethodsWe developed an isogenic cell line-derived xenograft model to perform transcriptome-wide analyses of trastuzumab-sensitive and -resistant tumors. To validate key findings, we employed a 3D cancer-immune co-culture system capable of quantifying antibody-dependent cellular cytotoxicity (ADCC). ResultsTranscriptomic profiling revealed how trastuzumab treatment shifts tumor transcriptomes, including changes that remodel the metabolic landscape and distinct gene signatures associated with resistance, notably the upregulation of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3). Functional studies demonstrated that PFKFB3 promotes trastuzumab resistance by inducing metabolic rewiring and reducing ADCC. Silencing PFKFB3 restored immune-mediated cytotoxicity. Clinical dataset analyses confirmed that elevated PFKFB3 expression correlates with reduced overall and progression-free survival, and with incomplete pathological response to trastuzumab. ConclusionsPFKFB3 upregulation drives metabolic adaptations that confer resistance to trastuzumab in HER2+ breast cancer. These findings highlight PFKFB3 as a promising therapeutic target to overcome resistance and improve patient outcomes. HighlightsO_LIPFKFB3 upregulation promotes trastuzumab resistance in HER2+ breast cancer. C_LIO_LITranscriptomic profiling reveals metabolic shifts linked to resistance. C_LIO_LISilencing PFKFB3 restores ADCC and sensitizes cancer cells to trastuzumab. C_LIO_LIHigh PFKFB3 expression correlates with poor survival and treatment response. C_LIO_LIPFKFB3 is a potential therapeutic target to overcome trastuzumab resistance. C_LI

cancer biology↗

bioRxiv2025

Fine needle aspiration biopsy of breast specimens effectively harvests cells for patient-derived organoids modeling breast ductal carcinoma in situ

BackgroundPatient-derived organoids (PDOs) generated from benign breast tissue and breast carcinomas have successfully recapitulated their respective in vivo counterparts. PDOs model tumorigenesis and allow for screening of novel therapeutics personalized to individual patients. However, acquiring cells to generate PDOs is cumbersome. We demonstrate the feasibility of fine needle aspiration biopsy (FNAB) for harvesting cells for PDOs modeling ductal carcinoma in situ (DCIS). MethodsSurgical specimens from patients with biopsy-proven DCIS were used for this study. Core needle biopsy (CNB) was performed on fresh specimens in the operating room, and tissue was mechanically dissociated before culture in basement membrane extract (BME) and organoid medium to generate PDOs. FNAB was performed in the gross room on fresh specimens, and the remaining aspirate was similarly submitted for PDO culture. ResultsPDOs were successfully generated in 15/18 specimens obtained by CNB and 7/11 specimens obtained by FNAB. The average time to initial organoid growth was 4 days for FNAB specimens compared to 19.3 days for CNB specimens. Tumor cells were seen on 7/11 FNAB smears and 16/18 CNB touch preps. Immunofluorescence staining confirmed the presence of both luminal and myoepithelial cells in derived PDOs. ConclusionsFNAB effectively obtains cells for PDOs modeling DCIS. CNB after mincing yielded PDOs with a high success rate, but they were slow to establish. Notably, the time to organoid growth was significantly shorter for FNAB specimens. Thus, FNAB offers an efficient alternative for breast PDO culture and can reduce the time and resources spent on generating PDO cultures.

cell biology↗

bioRxiv2022

A reversible SRC-relayed COX2-inflammatory program drives therapeutic resistance in BRAF(V600E) colorectal tumors

BRAFV600E mutation confers a poor prognosis in metastatic colorectal cancer (CRC) despite combinatorial targeted therapies based on the latest understanding of signaling circuitry. To identify parallel resistance mechanisms induced by BRAF/MEK/EGFR co-targeting, we used a high throughput kinase activity mapping platform. We found that SRC kinases are systematically activated in BRAFV600E CRC following targeted inhibition of BRAF {+/-} EGFR, and that coordinated targeting of SRC with BRAF {+/-} EGFR increases efficacy in vitro and in vivo. SRC drives resistance to BRAF {+/-} anti-EGFR therapy independently of ERK signaling by inducing transcriptional reprogramming via beta-catenin (CTNNB1). The EGFR-independent compensatory activation of SRC kinases is mediated by an autocrine prostaglandin E2-loop that can be blocked with cyclooxygenase-2 (COX2) inhibitors. Co-targeting of COX2 with BRAF+EGFR promotes durable suppression of tumor growth in patient-derived tumor xenograft (PDX) models. COX2 inhibition represents a novel drug-repurposing strategy to overcome therapeutic resistance in BRAFV600E CRC.

cancer biology↗