Project description:Inter-patient and intra-tumoral heterogeneity complicate the identification of predictive biomarkers and effective treatments for basal triple negative breast cancer (b-TNBC). Invasion is the initiating event in metastasis and can occur by both collective and single-cell mechanisms. We cultured primary organoids from a b-TNBC genetically engineered mouse model in 3D collagen gels to characterize their invasive behavior. We observed that organoids from the same tumor presented different phenotypes that we classified as non-invasive, collective and disseminative. To identify molecular regulators driving these invasive phenotypes, we developed a workflow to isolate individual organoids from the collagen gels based on invasive morphology and perform RNA sequencing. We next tested the requirement of differentially regulated genes for invasion using shRNA knock-down. Strikingly, KRAS was required for both collective and disseminative phenotypes. We then performed a drug screen targeting signaling nodes upstream and downstream of KRAS. We found that inhibition of EGFR, MAPK/ERK, or PI3K/AKT signaling reduced invasion. Of these, ERK inhibition was striking for its ability to potently inhibit collective invasion and dissemination. We conclude that different cancer cells in the same b-TNBC tumor can express different metastatic molecular programs and identified KRAS and ERK as essential regulators of collective and single cell dissemination.
Project description:Almost half of all patients diagnosed with colorectal cancer develop liver metastases. The potential role of intra-individual metastatic heterogeneity remains poorly characterized. By high-resolution DNA copy number analyses and a novel approach based on pair-wise genetic distance, we examined the genetic heterogeneity among multiple liver metastatic deposits obtained from 45 patients subject to curative liver resection. We found large variation in intra-individual metastatic heterogeneity. A high level of heterogeneity was associated with poor patient survival. Patients with metachronous metastases who received chemotherapy had significantly more heterogeneity than chemonaïve patients.
Project description:Desmoid tumors are bland fibroblastic tumors with little histologic variation in different regions of the tumor. While desmoid tumors do not metastasize, they have a high rate of local recurrence after complete resection and no reliable predictors of clinical behavior exist. The presence of molecular intra- and inter-tumor heterogeneity has been well established in other, higher grade, sarcomas but little is known about molecular variability within histologically bland lesions. In this study, we sought to examine the extent of intra- and inter-tumoral clonal heterogeneity of desmoid tumors, which may contribute to their pathogenesis and possible relapse. We performed analysis of DNA methylation, DNA copy number alterations, point mutations and gene expression on 24 specimens from different areas from primary and recurrent desmoid tumors from 3 patients (7-9 specimens per patient). The studies showed a remarkable heterogeneity of DNA methylation, DNA copy number alterations, point mutations or gene expression in different regions in primary or recurrent tumors in each patient. We discovered the evidence for subclonal alterations in different areas of individual tumors. Among the four types of data, the transcriptomic profiles showed the highest degree of variability within tumors and between different tumors from the same patient. Gene expression signatures associated with favorable and unfavorable outcome were detected in different regions within the same tumor. This study shows an unexpected degree of intra- and inter-tumor heterogeneity in desmoid tumors. Our analysis indicates that even in this histologically monotonous lesion, molecular analysis of a single tumor biopsy may underestimate the magnitude of molecular alterations. We demonstrate that molecular intra- and inter-tumor heterogeneity is an important consideration in drug development and validation of prognostic and predictive biomarkers for these tumors.
Project description:Desmoid tumors are bland fibroblastic tumors with little histologic variation in different regions of the tumor. While desmoid tumors do not metastasize, they have a high rate of local recurrence after complete resection and no reliable predictors of clinical behavior exist. The presence of molecular intra- and inter-tumor heterogeneity has been well established in other, higher grade, sarcomas but little is known about molecular variability within histologically bland lesions. In this study, we sought to examine the extent of intra- and inter-tumoral clonal heterogeneity of desmoid tumors, which may contribute to their pathogenesis and possible relapse. We performed analysis of DNA methylation, DNA copy number alterations, point mutations and gene expression on 24 specimens from different areas from primary and recurrent desmoid tumors from 3 patients (7-9 specimens per patient). The studies showed a remarkable heterogeneity of DNA methylation, DNA copy number alterations, point mutations or gene expression in different regions in primary or recurrent tumors in each patient. We discovered the evidence for subclonal alterations in different areas of individual tumors. Among the four types of data, the transcriptomic profiles showed the highest degree of variability within tumors and between different tumors from the same patient. Gene expression signatures associated with favorable and unfavorable outcome were detected in different regions within the same tumor. This study shows an unexpected degree of intra- and inter-tumor heterogeneity in desmoid tumors. Our analysis indicates that even in this histologically monotonous lesion, molecular analysis of a single tumor biopsy may underestimate the magnitude of molecular alterations. We demonstrate that molecular intra- and inter-tumor heterogeneity is an important consideration in drug development and validation of prognostic and predictive biomarkers for these tumors.
Project description:Deciphering intra- and inter-tumoral heterogeneity is essential for understanding gastric cancer (GC) biology and identifying effective therapeutic targets. We used single-cell RNA sequencing (scRNA-seq) to reveal the transcriptional heterogeneity of diverse cells within primary and metastatic GC and their roles in disease progression.
Project description:Tumour heterogeneity has been the main obstacle to the clinical efficacy of targeted and immunotherapy in cancer. An accurate understanding and recognition of tumour heterogeneity is critical in the clinical management of cancer patients. Here, we utilised single-cell RNA sequencing (scRNA-seq) to uncover the intra- and inter-tumoural heterogeneity of liver metastases from a patient with metastatic uveal melanoma.
Project description:Epigenetic heterogeneity is emerging as a significant phenotypic feature of tumors. In diffuse large B-cell lymphomas (DLBCLs), increased cytosine methylation heterogeneity is associated with poor clinical outcome, yet the biological mechanisms driving epigenetic heterogeneity remain unclear. Activation-induced cytidine deaminase (AICDA), an enzyme that deaminates and facilitates demethylation of DNA methyl-cytosines in germinal center (GC) B-cells, is required for DLBCL pathogenesis and linked to inferior clinical outcomes. Here, we show that overexpression of AICDA causes more aggressive disease and worse outcome in BCL2-driven murine lymphomas. This phenotype was associated with significantly increased focal inter-tumor and intra-tumor cytosine methylation heterogeneity as compared to control lymphomas, but not with increased mutational burden. AICDA-mediated epigenetic heterogeneity was accompanied by DNA hypomethylation. Reciprocally, we observed that the focal inter-individual and intra-individual cytosine methylation heterogeneity characteristic of normal GC B-cells was lost upon depletion of AICDA. There was significant overlap of AICDA-induced methylation heterogeneity foci in GC B-cells and murine lymphomas. These observations are relevant to human patients, since DLBCLs with high AICDA expression likewise manifest extensive increases in focal inter-patient and intra-patient heterogeneity as compared to DLBCLs with low AICDA expression. Affected regions significantly overlapped with those found in murine AICDA-overexpressing lymphomas. Our results identify AICDA as a novel source of epigenetic plasticity and heterogeneity in B-cell lymphomas with potential significance for other tumors that express cytosine deaminases.
Project description:The inter-patient variability of tumor proteomes has been investigated on a large scale but many tumors display also intra-tumoral heterogeneity (ITH) regarding morphological and genetic features. To what extent the local proteome of tumors intrinsically differs remains largely unknown. Here, we used hepatocellular carcinoma (HCC) as a model system, to quantify both inter- and intra-tumor heterogeneity across human patient specimens with spatial resolution. We first defined proteomic features that robustly distinguish neoplastic from the directly adjacent non-neoplastic tissue by integrating proteomic data from human patient samples and genetically defined mouse models with available gene expression data. We then demonstrated the existence of intra-tumoral variations in protein abundance that re-occur across different patient samples, and affect clinically relevant proteins, even in the absence of obvious morphological differences or genetic alterations. Our work demonstrates the suitability and the benefits of using mass spectrometry based proteomics to analyze diagnostic tumor specimens with spatial resolution
Project description:We classified samples and deciphered a key genes signature of intratumor heterogeneity by Principal Component Analysis and Weighted Gene Co-expression Network Analysis. At the genome level, we identified common GB copy number alterations and but a strong inter-individual molecular heterogeneity.