Biology subjects

Rakha, E. A.

Publications and source records attributed to Rakha, E. A..

3 recordsLinked to original sources

bioRxiv2022

Utility of stromal lymphocytes in diagnosis and predicting upgrade of B3 breast lesions from core biopsies

For more than two decades attempts have been made to identify a subset of women diagnosed with lesions with uncertain malignant potential (B3 lesions) who could safely be observed rather than being treated with surgical excision and/or chemoprevention. Various histopathological, clinical and imaging parameters for risk recommendation have been evaluated, with little impact on clinical practice. The primary reason for surgery is to rule out an upgrade lesion to either ductal carcinoma in situ (DCIS) or invasive breast cancer (IBC). While on average 30% of these patients are upgraded after diagnostic biopsy, a large number are over treated,making this an important harm of screening. Here we evaluated stromal lymphocytes from B3 biopsies (n=264) as a predictive biomarker for upgrade. A higher number of stromal lymphocytes were observed in upgraded B3 lesions than non-upgraded (p< 0.01, zero inflated binomial model) for both ductal and papillary lesions (n=174). This observation was validated in an independent cohort (p<0.001, p<0.05, zero binomial model, ductal and papillary lesions, respectively) (n=90). Our data suggested that the presence of [≥]5% of lymphocytes in the surrounding specialised stroma of B3 lesions are predictive of B3 lesions being upgraded with a specificity of 93% and 87% in our discovery and validation cohorts, respectively. The area under the curve (AUC) for the discovery cohort using lymphocyte count and age as variables was 0.77 and was validated with an AUC of 0.81 in the validation cohort. In conclusion, we can identify a subset of the patients at risk of upgrade with high specificity. Assessing the tumour microenvironment including stromal lymphocytes may contribute to reducing unnecessary surgeries in the clinic.

cancer biology↗

bioRxiv2021

Epigenome erosion drives neural crest-like phenotypic mimicry in triple-negative breast cancer and other SOX10+ malignancies

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSBackgroundC_ST_ABSIntratumoural heterogeneity is a poor prognostic feature in triple-negative breast cancer (TNBC) and other high-grade malignancies. It is caused by genomic instability and phenotypic plasticity, but how these features co-evolve during tumour development remains unclear. SOX10 is a transcription factor, neural crest stem cell (NCSC) specifier and candidate mediator of cancer-associated phenotypic plasticity. MethodsUsing immunophenotyping, we investigated the expression of SOX10 in normal human breast tissue and breast cancer (n=21 cosmetic breast reduction and 1,860 tumour samples with clinical annotation). We then defined the context and evolution of its expression in TNBC compared to 21 other malignancies using systems-level transcriptomics. ResultsSOX10 was detected in nuclei of normal mammary luminal progenitor cells, the histogenic origin of most TNBCs. In breast cancer, nuclear SOX10 predicted poor outcome amongst cross-sectional (log-rank p=0.0015, hazard ratio 2.02, n=224) and metaplastic (log-rank p=0.04, n=66) TNBCs. Systems-level transcriptional network analysis identified a core module in SOX10s normal mammary epithelial transcription program that is rewired to NCSC genes in TNBC. Reprogramming was proportional to DNA damage and genome-wide promoter hypomethylation, particularly at CpG island shores. Using a novel network analysis pipeline, we found that NCSC-like transcriptional reprogramming is also strongly associated with promoter hypomethylation in other SOX10+ malignancies: glioma and melanoma. ConclusionsWe propose that cancer-associated genome hypomethylation simulates the open chromatin landscape of more primitive cell states, and that on this relatively unrestricted background, SOX10 recreates its ancestral gene regulatory circuits by default. These findings provide new insights about the basis of intratumoural heterogeneity and resurrection of developmental phenotypes in cancer; and highlight the potential for therapeutics that limit chromatin remodelling.

cancer biology↗

bioRxiv2019

Global kinome silencing combined with 3D invasion screening of the tumor microenvironment identifies fibroblast-expressed PIK3Cδ involvement in triple-negative breast cancer progression

As there is growing evidence for the tumor microenvironments (TME) role in tumorigenesis, we sought to investigate the role of fibroblast-expressed kinases in triple negative breast cancer (TNBC). Using a high-throughput kinome screen combined with 3D invasion assays, we identified fibroblast-expressed PIK3C{delta} (f-PIK3C{delta}) as a key regulator of progression. Although PIK3C{delta} has been mainly described in leucocytes, we detected high expression in primary fibroblasts derived from TNBC patients, while PIK3C{delta} was undetectable in cancer epithelial cell lines. Genetic and pharmacologic gain- and loss-of functions experiments verified the contribution of f-PIK3C{delta} in TNBC cell invasion. By employing an integrated secretomics and transcriptomics analysis, we revealed a paracrine mechanism via which f-PIK3C{delta} confers its pro-tumorigenic effects. Inhibition of f-PIK3C{delta} promoted the secretion of factors, including PLGF and BDNF, which subsequently led to upregulation of NR4A1 in TNBC cells where it acts as a tumor suppressor. Inhibition of PIK3C{delta} in an orthotopic BC mouse model reduced tumor growth only after inoculation with fibroblasts, indicating a role of f-PIK3C{delta} in cancer progression. Similar results were observed in the MMTV-PyMT transgenic BC mouse model, in addition to a decrease on tumor metastasis emphasizing the potential immune-independent effects of PIK3C{delta} inhibition. Finally, analysis of BC patient cohorts and TCGA datasets identified f-PIK3C{delta} (protein and mRNA levels) as an independent prognostic factor for overall and disease free survival, highlighting it as a therapeutic target for TNBC.

cancer biology↗