Project description:We have developed cdk4/hTERT-immortalized normal human bronchial epithelial cells (HBECs) to study lung cancer pathogenesis. By studying the oncogenic effect of common lung cancer alterations (p53, KRAS, and c-MYC) we demonstrate the ability of this model to characterize the stepwise transformation of bronchial epithelial cells to full malignancy. Using HBECs derived from multiple individuals we found: 1) the combination of five genetic alterations (p53, KRASV12, c-MYC, CDK4 and hTERT) is sufficient for full tumorigenic conversion of HBECs; 2) high levels of KRASV12 are required for full malignant transformation of HBECs, however these levels also stimulate oncogene-induced senescence; 3) RAS-induced senescence is largely bypassed with loss of p53 function; 4) over-expression of c-MYC greatly enhances malignancy but only in the context of sh-p53+KRASV12; 5) HBECs from different individuals vary in their sensitivity to transformation by these oncogenic manipulations; 6) serum-induced epithelial-to-mesenchymal transition (EMT) increases in vivo tumorigenicity; 7) genetically-identical clones of transformed HBECs exhibit pronounced differences in tumor growth, histology, and differentiation as well as sensitivity to standard platinum-based chemotherapies; and 8) an mRNA signature derived from tumorigenic and non-tumorigenic clones is predictive of outcome in lung cancer patients. Collectively, we demonstrate this HBEC model system can be used to study the effect of oncogenic mutations on malignant progression, oncogene-induced senescence, and EMT along with clinically translatable applications such as development of prognostic signatures and drug response phenotypes. Human bronchial epithelial cells (HBECs) immortalized with cdk4 and hTERT were transformed with p53 knockdown, KrasV12 and cMYC over-expression and profiled on Illumina HumanHT-12 V4.0 expression beadchips. Transformed HBECs were grown in two different growth media: KSFM (defined, serum-free medium) or R10 (RPMI with 10% FBS) as indicated. Clones were isolated from HBECs with sh-p53 + KrasV12 and sh-p53 + KrasV12 + cMYC.

Project description:Tumour initiation and progression requires the metabolic rewiring of cancer cells. Fumarate hydratase (FH), a mitochondrial enzyme that catalyses the reversible hydration of fumarate to malate in the TCA cycle, has been identified as a bona fide tumour suppressor . FH loss predisposes to Hereditary Leiomyomatosis and Renal Cell Carcinoma (HLRCC), a cancer syndrome characterized by the presence of benign tumours of the skin and uterus, and a highly aggressive form of renal cancer. Its loss leads to aberrant accumulation of fumarate, an oncometabolite that drives malignant transformation . Even though the link between FH loss, fumarate accumulation and HLRCC is well-known, the associated tumorigenic mechanism is it is still not fully understood. Indeed, although HLRCC tumours metastasize even when small, Fh1-deficient mice develop premalignant cysts in the kidneys, rather than overt carcinomas. Interestingly, these cysts are positive for the key tumour suppressor p21. Since p21 expression is a central trigger of cellular senescence, it is postulated that this process could be an obstacle for tumorigenesis in Fh1-deficient cells. Consistent with this hypothesis, HLRCC patients harbour the epigenetic suppression of p16, another key player of senescence. Here, we have confirmed that additional oncogenic events independent from a senescence bypass are required to allow full-blown transformation in FH deficient cells. Moreover, a genome wide CRISPR/Cas9 screen identified HIRA as a target that, when ablated, increases proliferation and invasion in Fh1-deficient cells. Moreover, Fh1 and Hira-deficient cells lead to the development of tumours and invasive features in the kidney in vivo. Strikingly, Hira depletion in Fh1 deficient cells controls the activation of a MYC and E2F-dependent transcriptional and metabolic program, which is known to play different oncogenic roles during tumour initiation and progression. Of note, the activation of these programs is independent of H3.3 deposition into the chromatin, known to be controlled by HIRA. Overall, we have identified a novel oncogenic event occurring in FH deficient tumours, which will be instrumental for understanding mechanisms of tumorigenesis in HLRCC and the development of targeted treatments.

Project description:Tumour initiation and progression requires the metabolic rewiring of cancer cells. Fumarate hydratase (FH), a mitochondrial enzyme that catalyses the reversible hydration of fumarate to malate in the TCA cycle, has been identified as a bona fide tumour suppressor . FH loss predisposes to Hereditary Leiomyomatosis and Renal Cell Carcinoma (HLRCC), a cancer syndrome characterized by the presence of benign tumours of the skin and uterus, and a highly aggressive form of renal cancer. Its loss leads to aberrant accumulation of fumarate, an oncometabolite that drives malignant transformation . Even though the link between FH loss, fumarate accumulation and HLRCC is well-known, the associated tumorigenic mechanism is it is still not fully understood. Indeed, although HLRCC tumours metastasize even when small, Fh1-deficient mice develop premalignant cysts in the kidneys, rather than overt carcinomas. Interestingly, these cysts are positive for the key tumour suppressor p21. Since p21 expression is a central trigger of cellular senescence, it is postulated that this process could be an obstacle for tumorigenesis in Fh1-deficient cells. Consistent with this hypothesis, HLRCC patients harbour the epigenetic suppression of p16, another key player of senescence. Here, we have confirmed that additional oncogenic events independent from a senescence bypass are required to allow full-blown transformation in FH deficient cells. Moreover, a genome wide CRISPR/Cas9 screen identified HIRA as a target that, when ablated, increases proliferation and invasion in Fh1-deficient cells. Moreover, Fh1 and Hira-deficient cells lead to the development of tumours and invasive features in the kidney in vivo. Strikingly, Hira depletion in Fh1 deficient cells controls the activation of a MYC and E2F-dependent transcriptional and metabolic program, which is known to play different oncogenic roles during tumour initiation and progression. Of note, the activation of these programs is independent of H3.3 deposition into the chromatin, known to be controlled by HIRA. Overall, we have identified a novel oncogenic event occurring in FH deficient tumours, which will be instrumental for understanding mechanisms of tumorigenesis in HLRCC and the development of targeted treatments. Part 2 of this study emoployed a second FH-null clone to complement Part 1 of the study.

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Human lung epithelial cells progressed to malignancy through specific oncogenic manipulations

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