Ovarian cancer (OC) is a heterogeneous disease usually diagnosed at a late stage. Experimental in vitro models that faithfully capture the hallmarks and tumor heterogeneity of OC are limited and hard ...to establish. We present a protocol that enables efficient derivation and long-term expansion of OC organoids. Utilizing this protocol, we have established 56 organoid lines from 32 patients, representing all main subtypes of OC. OC organoids recapitulate histological and genomic features of the pertinent lesion from which they were derived, illustrating intra- and interpatient heterogeneity, and can be genetically modified. We show that OC organoids can be used for drug-screening assays and capture different tumor subtype responses to the gold standard platinum-based chemotherapy, including acquisition of chemoresistance in recurrent disease. Finally, OC organoids can be xenografted, enabling in vivo drug-sensitivity assays. Taken together, this demonstrates their potential application for research and personalized medicine.
Much controversy surrounds the cell-of-origin of mutant K-Ras (K-RasG12D)–induced lung adenocarcinoma. To shed light on this issue, we have used technology that enables us to conditionally target ...K-RasG12D expression in Surfactant Protein C (SPC) ⁺ alveolar type 2 cells and in Clara cell antigen 10 (CC10) ⁺ Clara cells by use of cell-type–restricted recombinant Adeno-Cre viruses. Experiments were performed both in the presence and absence of the tumor suppressor gene p53, enabling us to assess what effect the cell-of-origin and the introduced genetic lesions have on the phenotypic characteristics of the resulting adenocarcinomas. We conclude that both SPC-expressing alveolar type 2 cells and CC10-expressing Clara cells have the ability to initiate malignant transformation following the introduction of these genetic alterations. The lungs of K-Ras ˡᵒˣ–Sᵗᵒᵖ–ˡᵒˣ–ᴳ¹²ᴰ/⁺ and K-Ras ˡᵒˣ–Sᵗᵒᵖ–ˡᵒˣ–ᴳ¹²ᴰ/⁺;tumor suppressor gene Trp53 F/F mice infected with Adeno5–SPC–Cre and Adeno5–CC10–Cre viruses displayed differences in their tumor spectrum, indicating distinct cellular routes of tumor initiation. Moreover, using a multicolor Cre reporter line, we demonstrate that the resulting tumors arise from a clonal expansion of switched cells. Taken together, these results indicate that there are multiple cellular paths to K-RasG12D–induced adenocarcinoma and that the initiating cell influences the histopathological phenotype of the tumors that arise.
Small cell lung cancer (SCLC) is one of the most lethal human malignancies. To investigate the cellular origin(s) of this cancer, we assessed the effect of
Trp53 and
Rb1 inactivation in distinct cell ...types in the adult lung using adenoviral vectors that target Cre recombinase to Clara, neuroendocrine (NE), and alveolar type 2 (SPC-expressing) cells. Using these cell type-restricted Adeno-
Cre viruses, we show that loss of
Trp53 and
Rb1 can efficiently transform NE and SPC-expressing cells leading to SCLC, albeit SPC-expressing cells at a lesser efficiency. In contrast, Clara cells were largely resistant to transformation. The results indicate that although NE cells serve as the predominant cell of origin of SCLC a subset of SPC-expressing cells are also endowed with this ability.
► Cell-specific targeting in the lung is achieved using a series of Adeno-Cre viruses ► Loss of
Trp53 and
Rb1 in neuroendocrine cells effectively initiates SCLC in vivo ► Transformation of a rare SPC-positive cell by
Trp53 and
Rb1 loss initiates SCLC ► Loss of
Trp53 and
Rb1 in Clara cells does not lead to tumor formation
Lung squamous cell carcinoma (LSCC) is a devastating malignancy with no effective treatments, due to its complex genomic profile. Therefore, preclinical models mimicking its salient features are ...urgently needed. Here we describe mouse models bearing various combinations of genetic lesions predominantly found in human LSCC. We show that SOX2 but not FGFR1 overexpression in tracheobronchial basal cells combined with Cdkn2ab and Pten loss results in LSCC closely resembling the human counterpart. Interestingly, Sox2;Pten;Cdkn2ab mice develop LSCC with a more peripheral location when Club or Alveolar type 2 (AT2) cells are targeted. Our model highlights the essential role of SOX2 in commanding the squamous cell fate from different cells of origin and represents an invaluable tool for developing better intervention strategies.
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•Pten;Cdkn2ab loss causes a diversity of tumors in tracheobronchial basal cells•SOX2 overexpression is crucial in promoting LSCC upon loss of Pten;Cdkn2ab•Sox2;Pten;Cdkn2ab mice develop LSCC from Basal, Alveolar type 2, and Club cells•Mouse LSCC phenotypically and molecularly resembles the human counterpart
Ferone et al. establish mouse models bearing various combinations of genetic alterations commonly found in human lung squamous cell carcinoma and show that SOX2, but not FGFR1, overexpression induces the squamous cell fate from different cells of origin carrying the same combined Cdkn2ab and Pten loss.
L‐asparaginase (ASNase) serves as an effective drug for adolescent acute lymphoblastic leukemia. However, many clinical trials indicated severe ASNase toxicity in patients with solid tumors, with ...resistant mechanisms not well understood. Here, we took a functional genetic approach and identified SLC1A3 as a novel contributor to ASNase resistance in cancer cells. In combination with ASNase, SLC1A3 inhibition caused cell cycle arrest or apoptosis, and myriads of metabolic vulnerabilities in tricarboxylic acid (TCA) cycle, urea cycle, nucleotides biosynthesis, energy production, redox homeostasis, and lipid biosynthesis. SLC1A3 is an aspartate and glutamate transporter, mainly expressed in brain tissues, but high expression levels were also observed in some tumor types. Here, we demonstrate that ASNase stimulates aspartate and glutamate consumptions, and their refilling through SLC1A3 promotes cancer cell proliferation. Lastly, in vivo experiments indicated that SLC1A3 expression promoted tumor development and metastasis while negating the suppressive effects of ASNase by fueling aspartate, glutamate, and glutamine metabolisms despite of asparagine shortage. Altogether, our findings identify a novel role for SLC1A3 in ASNase resistance and suggest that restrictive aspartate and glutamate uptake might improve ASNase efficacy with solid tumors.
Synopsis
While L‐asparaginase is an effective drug for the treatment of childhood leukemia, toxicity and tolerance hamper its further usage in patients with solid tumors. Here, a genome‐wide functional screen identifies a role for amino acid transporter SLC1A3 in asparaginase resistance in cancer cells, suggesting a therapeutic perspective for restrictive aspartate and glutamate uptake in solid tumors.
Loss‐of‐function screen identifies SLC1A3 as facilitator of asparaginase resistance.
SLC1A3 is highly expressed in solid tumors.
Combined SLC1A3 blockade and asparaginase treatment impair cell growth in vitro and tumorigenesis in vivo.
Supplementation of intracellular aspartate and glutamate levels by SLC1A3 promotes cancerogenesis.
Amino acid transporter SLC1A3 facilitates cancer development by circumventing amino acid deprivation induced by asparaginase treatment.
Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumor, and no effective treatment is available to date. Mouse models of SCLC based on the inactivation of Rb1 and Trp53 show frequent ...amplifications of the Nfib and Mycl genes. Here, we report that, although overexpression of either transcription factor accelerates tumor growth, NFIB specifically promotes metastatic spread. High NFIB levels are associated with expansive growth of a poorly differentiated and almost exclusively E-cadherin (CDH1)-negative invasive tumor cell population. Consistent with the mouse data, we find that NFIB is overexpressed in almost all tested human metastatic high-grade neuroendocrine lung tumors, warranting further assessment of NFIB as a tumor progression marker in a clinical setting.
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•NFIB drives tumor initiation and progression in mouse models of SCLC•NFIB enhances metastasis and changes the metastatic profile•NFIB promotes dedifferentiation and invasion in SCLC•NFIB marks stage III/IV high-grade neuroendocrine carcinomas in patients
SCLC is a highly malignant cancer with an unmet need for better intervention strategies. Semenova et al. report that the transcription factor NFIB drives SCLC growth and metastasis, defines an aggressive tumor compartment in mice, and marks a subgroup of high-grade pulmonary neuroendocrine tumors (pNETs) in patients.
Patient-derived organoids (PDOs) are widely heralded as a drug-screening platform to develop new anti-cancer therapies. Here, we use a drug-repurposing library to screen PDOs of colorectal cancer ...(CRC) to identify hidden vulnerabilities within therapy-induced phenotypes. Using a microscopy-based screen that accurately scores drug-induced cell killing, we have tested 414 putative anti-cancer drugs for their ability to switch the EGFRi/MEKi-induced cytostatic phenotype toward cytotoxicity. A majority of validated hits (9/37) are microtubule-targeting agents that are commonly used in clinical oncology, such as taxanes and vinca-alkaloids. One of these drugs, vinorelbine, is consistently effective across a panel of >25 different CRC PDOs, independent of RAS mutational status. Unlike vinorelbine alone, its combination with EGFR/MEK inhibition induces apoptosis at all stages of the cell cycle and shows tolerability and effective anti-tumor activity in vivo, setting the basis for a clinical trial to treat patients with metastatic RAS-mutant CRC.
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•Imaging-based screening on organoids enables scoring of drug-induced cell killing•Targeting MAPK signaling sensitizes colon cancers for microtubule-targeting agents•Combining MAPK pathway inhibition and vinorelbine is tolerable and effective in vivo•Induced cell killing by the combination therapy is independent of cell-cycle stage
Targeted therapies against KRAS-mutant colorectal cancers have proven to be problematic, whereby induction of cytotoxicity remains incomplete even upon effective suppression of downstream MAPK pathway activity. Mertens et al. find that effective inhibition of MAPK signaling sensitizes cancer cells for microtubule-targeting agents.
The enzyme glutaminyl-peptide cyclotransferase-like protein (QPCTL) catalyzes the formation of pyroglutamate residues at the NH
2
-terminus of proteins, thereby influencing their biological ...properties. A number of studies have implicated QPCTL in the regulation of chemokine stability. Furthermore, QPCTL activity has recently been shown to be critical for the formation of the high-affinity SIRPα binding site of the CD47 "don't-eat-me" protein. Based on the latter data, interference with QPCTL activity -and hence CD47 maturation-may be proposed as a means to promote anti-tumor immunity. However, the pleiotropic activity of QPCTL makes it difficult to predict the effects of QPCTL inhibition on the tumor microenvironment (TME). Using a syngeneic mouse melanoma model, we demonstrate that QPCTL deficiency alters the intra-tumoral monocyte-to-macrophage ratio, results in a profound increase in the presence of pro-inflammatory cancer-associated fibroblasts (CAFs) relative to immunosuppressive TGF-β1-driven CAFs, and leads to an increased IFN and decreased TGF-β transcriptional response signature in tumor cells. Importantly, the functional relevance of the observed TME remodeling is demonstrated by the synergy between QPCTL deletion and anti PD-L1 therapy, sensitizing an otherwise refractory melanoma model to anti-checkpoint therapy. Collectively, these data provide support for the development of strategies to interfere with QPCTL activity as a means to promote tumor-specific immunity.
Class I histone deacetylases are critical regulators of gene transcription by erasing lysine acetylation. Targeting histone deacetylases using relative non-specific small molecule inhibitors is of ...major interest in the treatment of cancer, neurological disorders and acquired immune deficiency syndrome. Harnessing the therapeutic potential of histone deacetylase inhibitors requires full knowledge of individual histone deacetylases in vivo. As hematologic malignancies show increased sensitivity towards histone deacetylase inhibitors we targeted deletion of class I Hdac1 and Hdac2 to hematopoietic cell lineages. Here, we show that Hdac1 and Hdac2 together control hematopoietic stem cell homeostasis, in a cell-autonomous fashion. Simultaneous loss of Hdac1 and Hdac2 resulted in loss of hematopoietic stem cells and consequently bone marrow failure. Bone-marrow-specific deletion of Sin3a, a major Hdac1/2 co-repressor, phenocopied loss of Hdac1 and Hdac2 indicating that Sin3a-associated HDAC1/2-activity is essential for hematopoietic stem cell homeostasis. Although Hdac1 and Hdac2 show compensatory and overlapping functions in hematopoiesis, mice expressing mono-allelic Hdac1 or Hdac2 revealed that Hdac1 and Hdac2 contribute differently to the development of specific hematopoietic lineages.
Abstract
Background
The majority of
BRCA1
-mutant breast cancers are characterized by a triple-negative phenotype and a basal-like molecular subtype, associated with aggressive clinical behavior. ...Current treatment options are limited, highlighting the need for the development of novel targeted therapies for this tumor subtype.
Methods
Our group previously showed that EZH2 is functionally relevant in BRCA1-deficient breast tumors and blocking EZH2 enzymatic activity could be a potent treatment strategy. To validate the role of EZH2 as a therapeutic target and to identify new synergistic drug combinations, we performed a high-throughput drug combination screen in various cell lines derived from BRCA1-deficient and -proficient mouse mammary tumors.
Results
We identified the combined inhibition of EZH2 and the proximal DNA damage response kinase ATM as a novel synthetic lethality-based therapy for the treatment of BRCA1-deficient breast tumors. We show that the combined treatment with the EZH2 inhibitor GSK126 and the ATM inhibitor AZD1390 led to reduced colony formation, increased genotoxic stress, and apoptosis-mediated cell death in BRCA1-deficient mammary tumor cells in vitro. These findings were corroborated by in vivo experiments showing that simultaneous inhibition of EZH2 and ATM significantly increased anti-tumor activity in mice bearing BRCA1-deficient mammary tumors.
Conclusion
Taken together, we identified a synthetic lethal interaction between EZH2 and ATM and propose this synergistic interaction as a novel molecular combination for the treatment of
BRCA1
-mutant breast cancer.
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