RESUMEN
Cancer testis antigens (CTAs) are a collection of proteins whose expression is normally restricted to the gamete but abnormally activated in a wide variety of tumors. The CTA, Testis-specific serine kinase 6 (TSSK6), is essential for male fertility in mice. The functional relevance of TSSK6 to cancer, if any, has not previously been investigated. Here we find that TSSK6 is frequently anomalously expressed in colorectal cancer and patients with elevated TSSK6 expression have reduced relapse-free survival. Depletion of TSSK6 from colorectal cancer cells attenuates anchorage-independent growth, invasion, and growth in vivo. Conversely, overexpression of TSSK6 enhances anchorage independence and invasion in vitro as well as in vivo tumor growth. Notably, ectopic expression of TSSK6 in semi-transformed human colonic epithelial cells is sufficient to confer anchorage independence and enhance invasion. In somatic cells, TSSK6 co-localizes with and enhances the formation of paxillin and tensin-positive foci at the cell periphery, suggesting a function in focal adhesion formation. Importantly, TSSK6 kinase activity is essential to induce these tumorigenic behaviors. Our findings establish that TSSK6 exhibits oncogenic activity when abnormally expressed in colorectal cancer cells. Thus, TSSK6 is a previously unrecognized intervention target for therapy, which could exhibit an exceptionally broad therapeutic window.
Asunto(s)
Neoplasias Colorrectales , Regulación Neoplásica de la Expresión Génica , Proteínas Serina-Treonina Quinasas , Animales , Humanos , Masculino , Ratones , Carcinogénesis/genética , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/genética , Adhesiones Focales/metabolismo , Adhesiones Focales/genética , Invasividad Neoplásica , Paxillin/metabolismo , Paxillin/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Tensinas/metabolismo , Tensinas/genéticaRESUMEN
Therapy resistance and metastatic progression are primary causes of cancer-related mortality. Disseminated tumor cells possess adaptive traits that enable them to reprogram their metabolism, maintain stemness, and resist cell death, facilitating their persistence to drive recurrence. The survival of disseminated tumor cells also depends on their ability to modulate replication stress in response to therapy while colonizing inhospitable microenvironments. In this study, we discovered that the nuclear translocation of AXL, a TAM receptor tyrosine kinase, and its interaction with WRNIP1, a DNA replication stress response factor, promotes the survival of HER2+ breast cancer cells that are resistant to HER2-targeted therapy and metastasize to the brain. In preclinical models, knocking down or pharmacologically inhibiting AXL or WRNIP1 attenuated protection of stalled replication forks. Furthermore, deficiency or inhibition of AXL and WRNIP1 also prolonged metastatic latency and delayed relapse. Together, these findings suggest that targeting the replication stress response, which is a shared adaptive mechanism in therapy-resistant and metastasis-initiating cells, could reduce metachronous metastasis and enhance the response to standard-of-care therapies. SIGNIFICANCE: Nuclear AXL and WRNIP1 interact and mediate replication stress response, promote therapy resistance, and support metastatic progression, indicating that targeting the AXL/WRNIP1 axis is a potentially viable therapeutic strategy for breast cancer.
Asunto(s)
Neoplasias de la Mama , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Tirosina Quinasa del Receptor Axl , Proteínas Proto-Oncogénicas/metabolismo , Recurrencia Local de Neoplasia , Proteínas Tirosina Quinasas Receptoras/metabolismo , Resistencia a Antineoplásicos/genética , Línea Celular Tumoral , Microambiente Tumoral , ATPasas Asociadas con Actividades Celulares Diversas/metabolismo , Proteínas de Unión al ADN/metabolismoRESUMEN
Cancer testis antigens (CTAs) are a collection of proteins whose expression is normally restricted to the gamete, but abnormally activated in a wide variety of tumors. The CTA, Testis specific serine kinase 6 (TSSK6), is essential for male fertility in mice. Functional relevance of TSSK6 to cancer, if any, has not previously been investigated. Here we find that TSSK6 is frequently anomalously expressed in colorectal cancer and patients with elevated TSSK6 expression have reduced relapse free survival. Depletion of TSSK6 from colorectal cancer cells attenuates anchorage independent growth, invasion and growth in vivo. Conversely, overexpression of TSSK6 enhances anchorage independence and invasion in vitro as well as in vivo tumor growth. Notably, ectopic expression of TSSK6 in semi-transformed human colonic epithelial cells is sufficient to confer anchorage independence and enhance invasion. In somatic cells, TSSK6 co-localizes with and enhances the formation of paxillin and tensin positive foci at the cell periphery, suggesting a function in focal adhesion formation. Importantly, TSSK6 kinase activity is essential to induce these tumorigenic behaviors. Our findings establish that TSSK6 exhibits oncogenic activity when abnormally expressed in colorectal cancer cells. Thus, TSSK6 is a previously unrecognized intervention target for therapy, which could exhibit an exceptionally broad therapeutic window.
RESUMEN
Tumors anomalously induce the expression of meiotic genes, which are otherwise restricted only to developing gametes. If and how these aberrantly expressed meiotic proteins influence DNA metabolism is not clear, but could have important implications for how tumors acquire and mitigate genomic instability. HORMAD1 is a highly conserved meiotic protein that is frequently expressed in lung adenocarincoma where its expression correlates with reduced patient survival and increased mutation burden. Here, we find that HORMAD1 associates with the replisome and is critical for protecting stalled DNA replication forks. Loss of HORMAD1 leads to nascent DNA strand degradation, an event which is mediated by the MRE11-DNA2-BLM pathway. We find that these phenotypes are due to limited RAD51 loading onto stalled replication forks in the absence of HORMAD1. Ultimately, loss of HORMAD1 leads to increased DNA breaks and chromosomal defects, which is exacerbated dramatically by induction of replication stress. Tumor cells proliferate despite encountering chronic replication stress, placing them on the precipice of catastrophic genomic damage. Our data support the hypothesis that the aberrant expression of HORMAD1 is engaged to attenuate the accumulation of excessive DNA damage due to chronic replication stress, which may otherwise lead to accumulation of toxic levels of genomic instability.
Asunto(s)
Proteínas de Ciclo Celular , Replicación del ADN , Neoplasias , Humanos , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , ADN , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Inestabilidad Genómica , Neoplasias/genéticaRESUMEN
Tumors frequently activate the expression of genes that are only otherwise required for meiosis. HORMAD1, which is essential for meiotic recombination in multiple species, is expressed in over 50% of human lung adenocarcinoma cells (LUAD). We previously found that HORMAD1 promotes DNA double strand break (DSB) repair in LUAD. Here, we report that HORMAD1 takes on an additional role in protecting genomic integrity. Specifically, we find HORMAD1 is critical for protecting stalled DNA replication forks in LUAD. Loss of HORMAD1 leads to nascent DNA degradation, an event which is mediated by the MRE11-DNA2-BLM pathway. Moreover, following exogenous induction of DNA replication stress, HORMAD1 deleted cells accumulate single stranded DNA (ssDNA). We find that these phenotypes are the result of a lack of RAD51 and BRCA2 loading onto stalled replication forks. Ultimately, loss of HORMAD1 leads to increased DSBs and chromosomal aberrations in response to replication stress. Collectively, our data support a model where HORMAD1 expression is selected to mitigate DNA replication stress, which would otherwise induce deleterious genomic instability.
RESUMEN
Cancer testis antigens (CTAs) are proteins whose expression is normally restricted to the testis but anomalously activated in human cancer. In sperm, a number of CTAs support energy generation, however, whether they contribute to tumor metabolism is not understood. We describe human COX6B2, a component of cytochrome c oxidase (complex IV). COX6B2 is expressed in human lung adenocarcinoma (LUAD) and expression correlates with reduced survival time. COX6B2, but not its somatic isoform COX6B1, enhances activity of complex IV, increasing oxidative phosphorylation (OXPHOS) and NAD+ generation. Consequently, COX6B2-expressing cancer cells display a proliferative advantage, particularly in low oxygen. Conversely, depletion of COX6B2 attenuates OXPHOS and collapses mitochondrial membrane potential leading to cell death or senescence. COX6B2 is both necessary and sufficient for growth of human tumor xenografts in mice. Our findings reveal a previously unappreciated, tumor-specific metabolic pathway hijacked from one of the most ATP-intensive processes in the animal kingdom: sperm motility.
Asunto(s)
Adenocarcinoma del Pulmón/genética , Proliferación Celular/genética , Supervivencia Celular/genética , Complejo IV de Transporte de Electrones/genética , Neoplasias Pulmonares/genética , Fosforilación Oxidativa , Animales , Complejo IV de Transporte de Electrones/metabolismo , Células HEK293 , Humanos , Ratones , Ratones DesnudosRESUMEN
Cancer/testis (CT) antigens are proteins whose expression is normally restricted to germ cells yet aberrantly activated in tumors, where their functions remain relatively cryptic. Here we report that ZNF165, a CT antigen frequently expressed in triple-negative breast cancer (TNBC), associates with SMAD3 to modulate transcription of transforming growth factor ß (TGFß)-dependent genes and thereby promote growth and survival of human TNBC cells. In addition, we identify the KRAB zinc finger protein, ZNF446, and its associated tripartite motif protein, TRIM27, as obligate components of the ZNF165-SMAD3 complex that also support tumor cell viability. Importantly, we find that TRIM27 alone is necessary for ZNF165 transcriptional activity and is required for TNBC tumor growth in vivo using an orthotopic xenograft model in immunocompromised mice. Our findings indicate that aberrant expression of a testis-specific transcription factor is sufficient to co-opt somatic transcriptional machinery to drive a pro-tumorigenic gene expression program in TNBC.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteína smad3/metabolismo , Testículo/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Neoplasias de la Mama Triple Negativas/metabolismo , Animales , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Ratones , Transducción de Señal , Proteína smad3/genética , Neoplasias de la Mama Triple Negativas/genéticaRESUMEN
Ewing sarcoma is characterized by a pathognomonic chromosomal translocation that generates the EWSR1-FLI1 chimeric transcription factor. The transcriptional targets of EWSR1-FLI1 that are essential for tumorigenicity are incompletely defined. Here, we found that EWSR1-FLI1 modulates the expression of cancer/testis (CT) antigen genes, whose expression is biased to the testes but is also activated in cancer. Among these CT antigens, fetal and adult testis expressed 1 (FATE1) is most robustly induced. EWSR1-FLI1 associates with the GGAA repeats in the proximal promoter of FATE1, which exhibits accessible chromatin exclusively in mesenchymal progenitor cells (MPCs) and Ewing sarcoma cells. Expression of EWSR1-FLI1 in non-Ewing sarcoma cells and in MPCs enhances FATE1 mRNA and protein expression. Conversely, depletion of EWSR1-FLI1 in Ewing sarcoma cells leads to a loss of FATE1 expression. Importantly, we found that FATE1 is required for survival and anchorage-independent growth in Ewing sarcoma cells via attenuating the accumulation of BNIP3L, a BH3-only protein that is toxic when stabilized. This action appears to be mediated by the E3 ligase RNF183. We propose that engaging FATE1 function can permit the bypass of cell death mechanisms that would otherwise inhibit tumor progression.
Asunto(s)
Neoplasias Óseas/genética , Proteínas de Unión al ADN/genética , Proteínas de Fusión Oncogénica/genética , Sarcoma de Ewing/genética , Factores de Transcripción/genética , Neoplasias Óseas/metabolismo , Línea Celular Tumoral , Supervivencia Celular , Proteínas de Unión al ADN/metabolismo , Regulación Neoplásica de la Expresión Génica , Células HeLa , Células Hep G2 , Humanos , Proteínas de la Membrana/metabolismo , Regiones Promotoras Genéticas , Proteínas Proto-Oncogénicas/metabolismo , Sarcoma de Ewing/metabolismo , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Tumors of nearly every origin activate the expression of genes normally restricted to gametogenic cells. These genes encode proteins termed cancer/testis (CT) antigens, since expression outside of their naturally immune-privileged site can evoke an immune response. Despite extensive efforts to exploit CT antigens as immunotherapeutic targets, investigation of whether these proteins participate in tumorigenic processes has lagged. Here, we discuss emerging evidence that demonstrates that CT antigens can confer a selective advantage to tumor cells by promoting oncogenic processes or permitting evasion of tumor-suppressive mechanisms. These advances indicate the inherent flexibility of tumor cell regulatory networks to engage aberrantly expressed proteins to promote neoplastic behaviors, which could ultimately present novel therapeutic entry points.
Asunto(s)
Antígenos de Neoplasias/metabolismo , Carcinogénesis/inmunología , Regulación Neoplásica de la Expresión Génica/inmunología , Neoplasias/inmunología , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/inmunología , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Carcinogénesis/genética , Modelos Animales de Enfermedad , Drosophila melanogaster , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Neoplasias/patología , ProteolisisRESUMEN
Cancer testis antigens (CTA) are expressed in testis and placenta and anomalously activated in a variety of tumors. The mechanistic contribution of CTAs to neoplastic phenotypes remains largely unknown. Using a chemigenomics approach, we find that the CTA HORMAD1 correlates with resistance to the mitochondrial complex I inhibitor piericidin A in non-small cell lung cancer (NSCLC). Resistance was due to a reductive intracellular environment that attenuated the accumulation of free radicals. In human lung adenocarcinoma (LUAD) tumors, patients expressing high HORMAD1 exhibited elevated mutational burden and reduced survival. HORMAD1 tumors were enriched for genes essential for homologous recombination (HR), and HORMAD1 promoted RAD51-filament formation, but not DNA resection, during HR. Accordingly, HORMAD1 loss enhanced sensitivity to γ-irradiation and PARP inhibition, and HORMAD1 depletion significantly reduced tumor growth in vivo These results suggest that HORMAD1 expression specifies a novel subtype of LUAD, which has adapted to mitigate DNA damage. In this setting, HORMAD1 could represent a direct target for intervention to enhance sensitivity to DNA-damaging agents or as an immunotherapeutic target in patients.Significance: This study uses a chemigenomics approach to demonstrate that anomalous expression of the CTA HORMAD1 specifies resistance to oxidative stress and promotes HR to support tumor cell survival in NSCLC. Cancer Res; 78(21); 6196-208. ©2018 AACR.
Asunto(s)
Adenocarcinoma del Pulmón/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Proteínas de Ciclo Celular/metabolismo , Regulación Neoplásica de la Expresión Génica , Neoplasias Pulmonares/diagnóstico , Células A549 , Adenocarcinoma del Pulmón/metabolismo , Animales , Antígenos de Neoplasias/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Supervivencia Celular , Daño del ADN , Reparación del ADN , Femenino , Radicales Libres , Perfilación de la Expresión Génica , Humanos , Neoplasias Pulmonares/metabolismo , Ratones , Ratones Endogámicos NOD , Mutágenos , Trasplante de Neoplasias , Estrés Oxidativo , Pronóstico , Recombinación GenéticaRESUMEN
Autophagy is a cellular degradation pathway that is essential to maintain cellular physiology, and deregulation of autophagy leads to multiple diseases in humans. In a recent study, we discovered that the protein kinase WNK1 (WNK lysine deficient protein kinase 1) is an inhibitor of autophagy. The loss of WNK1 increases both basal and starvation-induced autophagy. In addition, the depletion of WNK1 increases the activation of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex, which is required to induce autophagy. Moreover, the loss of WNK1 increases the expression of ULK1 (unc-51 like kinase 1), which is upstream of the PtdIns3K complex. It also increases the pro-autophagic phosphorylation of ULK1 at Ser555 and the activation of AMPK (AMP-activated protein kinase), which is responsible for that phosphorylation. The inhibition of AMPK by compound C decreases the magnitude of autophagy induction following WNK1 loss; however, it does not prevent autophagy induction. We found that the UVRAG (UV radiation resistance associated gene), which is a component of the PtdIns3K, binds to the N-terminal region of WNK1. Moreover, WNK1 partially colocalizes with UVRAG and this colocalization decreases when autophagy is stimulated in cells. The loss of WNK1 also alters the cellular distribution of UVRAG. The depletion of the downstream target of WNK1, OXSR1/OSR1 (oxidative-stress responsive 1) has no effect on autophagy, whereas the depletion of its relative STK39/SPAK (serine/threonine kinase 39) induces autophagy under nutrient-rich and starved conditions.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Autofagia/fisiología , Transducción de Señal/fisiología , Proteína Quinasa Deficiente en Lisina WNK 1/metabolismo , Animales , Humanos , Proteínas Serina-Treonina Quinasas/metabolismo , Factores de Transcripción/metabolismoRESUMEN
The with-no-lysine (K) (WNK) kinases are an atypical family of protein kinases that regulate ion transport across cell membranes. Mutations that result in their overexpression cause hypertension-related disorders in humans. Of the four mammalian WNKs, only WNK1 is expressed throughout the body. We report that WNK1 inhibits autophagy, an intracellular degradation pathway implicated in several human diseases. Using small-interfering RNA-mediated WNK1 knockdown, we show autophagosome formation and autophagic flux are accelerated. In cells with reduced WNK1, basal and starvation-induced autophagy is increased. We also show that depletion of WNK1 stimulates focal class III phosphatidylinositol 3-kinase complex (PI3KC3) activity, which is required to induce autophagy. Depletion of WNK1 increases the expression of the PI3KC3 upstream regulator unc-51-like kinase 1 (ULK1), its phosphorylation, and activation of the kinase upstream of ULK1, the AMP-activated protein kinase. In addition, we show that the N-terminal region of WNK1 binds to the UV radiation resistance-associated gene (UVRAG) in vitro and WNK1 partially colocalizes with UVRAG, a component of a PI3KC3 complex. This colocalization decreases upon starvation of cells. Depletion of the SPS/STE20-related proline-alanine-rich kinase, a WNK1-activated enzyme, also induces autophagy in nutrient-replete or -starved conditions, but depletion of the related kinase and WNK1 substrate, oxidative stress responsive 1, does not. These results indicate that WNK1 inhibits autophagy by multiple mechanisms.
Asunto(s)
Autofagia/fisiología , Proteína Quinasa Deficiente en Lisina WNK 1/fisiología , Autofagia/genética , Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Línea Celular , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Técnicas de Silenciamiento del Gen , Células HeLa , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Modelos Biológicos , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , ARN Interferente Pequeño/genética , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Proteína Quinasa Deficiente en Lisina WNK 1/antagonistas & inhibidores , Proteína Quinasa Deficiente en Lisina WNK 1/genéticaRESUMEN
Triple-negative breast cancer (TNBC) is a highly heterogeneous disease with multiple, distinct molecular subtypes that exhibit unique transcriptional programs and clinical progression trajectories. Despite knowledge of the molecular heterogeneity of the disease, most patients are limited to generic, indiscriminate treatment options: cytotoxic chemotherapy, surgery, and radiation. To identify new intervention targets in TNBC, we used large-scale, loss-of-function screening to identify molecular vulnerabilities among different oncogenomic backgrounds. This strategy returned salt inducible kinase 2 (SIK2) as essential for TNBC survival. Genetic or pharmacological inhibition of SIK2 leads to increased autophagic flux in both normal-immortalized and tumor-derived cell lines. However, this activity causes cell death selectively in breast cancer cells and is biased toward the claudin-low subtype. Depletion of ATG5, which is essential for autophagic vesicle formation, rescued the loss of viability following SIK2 inhibition. Importantly, we find that SIK2 is essential for TNBC tumor growth in vivo Taken together, these findings indicate that claudin-low tumor cells rely on SIK2 to restrain maladaptive autophagic activation. Inhibition of SIK2 therefore presents itself as an intervention opportunity to reactivate this tumor suppressor mechanism.
Asunto(s)
Proteína 5 Relacionada con la Autofagia/genética , Claudinas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Neoplasias de la Mama Triple Negativas/patología , Animales , Autofagia , Proteína 5 Relacionada con la Autofagia/metabolismo , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Trasplante de Neoplasias , Proteínas Serina-Treonina Quinasas/metabolismo , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismoRESUMEN
Genes that are normally biased towards expression in the testis are often induced in tumor cells. These gametogenic genes, known as cancer-testis antigens (CTAs), have been extenstively investigated as targets for immunotherapy. However, despite their frequent detection, the degree to which CTAs support neoplastic invasion is poorly understood. Here, we find that the CTA genes SPANX-A/C/D and CTAG2 are coordinately induced in breast cancer cells and regulate distinct features of invasive behavior. Our functional analysis revealed that CTAG2 interacts with Pericentrin at the centrosome and is necessary for directional migration. Conversely, SPANX-A/C/D interacts with Lamin A/C at the inner nuclear membrane and is required for the formation of actin-rich cellular protrusions that reorganize the extracellular matrix. Importantly, SPANX-A/C/D was required for breast cancer cells to spontaneously metastasize to the lung, demonstrating that CTA reactivation can be critical for invasion dependent phenotypes in vivo. Moreover, elevated SPANX-A/C/D expression in breast cancer patient tumors correlated with poor outcome. Together, our results suggest that distinct CTAs promote tumor progression by regulating complementary cellular functions that are integrated together to induce invasive behavior.
Asunto(s)
Antígenos de Neoplasias/metabolismo , Antígenos de Superficie/metabolismo , Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/patología , Proteínas de Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Animales , Apoptosis , Neoplasias de la Mama/metabolismo , Movimiento Celular , Proliferación Celular , Femenino , Humanos , Ratones , Ratones Endogámicos NOD , Ratones SCID , Invasividad Neoplásica , Estadificación de Neoplasias , Pronóstico , Tasa de Supervivencia , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Tumours frequently activate genes whose expression is otherwise biased to the testis, collectively known as cancer-testis antigens (CTAs). The extent to which CTA expression represents epiphenomena or confers tumorigenic traits is unknown. In this study, to address this, we implemented a multidimensional functional genomics approach that incorporates 7 different phenotypic assays in 11 distinct disease settings. We identify 26 CTAs that are essential for tumor cell viability and/or are pathological drivers of HIF, WNT or TGFß signalling. In particular, we discover that Foetal and Adult Testis Expressed 1 (FATE1) is a key survival factor in multiple oncogenic backgrounds. FATE1 prevents the accumulation of the stress-sensing BH3-only protein, BCL-2-Interacting Killer (BIK), thereby permitting viability in the presence of toxic stimuli. Furthermore, ZNF165 promotes TGFß signalling by directly suppressing the expression of negative feedback regulatory pathways. This action is essential for the survival of triple negative breast cancer cells in vitro and in vivo. Thus, CTAs make significant direct contributions to tumour biology.
Asunto(s)
Antígenos de Neoplasias/genética , Carcinogénesis/genética , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias/genética , Factores de Transcripción/genética , Factor de Crecimiento Transformador beta/genética , Adenocarcinoma/genética , Adenocarcinoma/inmunología , Adenocarcinoma/mortalidad , Adenocarcinoma del Pulmón , Animales , Proteínas Reguladoras de la Apoptosis/genética , Línea Celular , Línea Celular Tumoral , Supervivencia Celular , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/mortalidad , Técnica del Anticuerpo Fluorescente , Células HCT116 , Células HEK293 , Humanos , Immunoblotting , Técnicas In Vitro , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/mortalidad , Proteínas de la Membrana/genética , Ratones Endogámicos NOD , Proteínas Mitocondriales , Trasplante de Neoplasias , Neoplasias/inmunología , Neoplasias/mortalidad , Pronóstico , Modelos de Riesgos Proporcionales , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal , Proteína smad7/genética , Factor de Crecimiento Transformador beta/inmunología , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/inmunología , Neoplasias de la Mama Triple Negativas/mortalidad , Ubiquitina-Proteína Ligasas/genética , Vía de Señalización WntRESUMEN
Non-small cell lung cancer (NSCLC) is notorious for its paltry responses to first-line therapeutic regimens. In contrast to acquired chemoresistance, little is known about the molecular underpinnings of the intrinsic resistance of chemo-naïve NSCLC. Here we report that intrinsic resistance to paclitaxel in NSCLC occurs at a cell-autonomous level because of the uncoupling of mitotic defects from apoptosis. To identify components that permit escape from mitotic stress-induced death, we used a genome-wide RNAi-based strategy, which combines a high-throughput toxicity screen with a live-cell imaging platform to measure mitotic fate. This strategy revealed that prolonging mitotic arrest with a small molecule inhibitor of the APC/cyclosome could sensitize otherwise paclitaxel-resistant NSCLC. We also defined novel roles for CASC1 and TRIM69 in supporting resistance to spindle poisons. CASC1, which is frequently co-amplified with KRAS in lung tumors, is essential for microtubule polymerization and satisfaction of the spindle assembly checkpoint. TRIM69, which associates with spindle poles and promotes centrosomal clustering, is essential for formation of a bipolar spindle. Notably, RNAi-mediated attenuation of CASC1 or TRIM69 was sufficient to inhibit tumor growth in vivo. On the basis of our results, we hypothesize that tumor evolution selects for a permissive mitotic checkpoint, which may promote survival despite chromosome segregation errors. Attacking this adaptation may restore the apoptotic consequences of mitotic damage to permit the therapeutic eradication of drug-resistant cancer cells.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Neoplasias Pulmonares/metabolismo , Mitosis , Estrés Fisiológico , Animales , Antineoplásicos/farmacología , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/genética , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Modelos Animales de Enfermedad , Resistencia a Antineoplásicos/genética , Femenino , Xenoinjertos , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones , Microtúbulos/metabolismo , Mitosis/efectos de los fármacos , Mitosis/genética , Paclitaxel/farmacología , Unión Proteica , Interferencia de ARN , Huso Acromático/metabolismo , Estrés Fisiológico/efectos de los fármacos , Estrés Fisiológico/genética , Proteínas de Motivos Tripartitos , Carga Tumoral/efectos de los fármacos , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
CUL7, OBSL1, and CCDC8 genes are mutated in a mutually exclusive manner in 3M and other growth retardation syndromes. The mechanism underlying the function of the three 3M genes in development is not known. We found that OBSL1 and CCDC8 form a complex with CUL7 and regulate the level and centrosomal localization of CUL7, respectively. CUL7 depletion results in altered microtubule dynamics, prometaphase arrest, tetraploidy, and mitotic cell death. These defects are recaptured in CUL7 mutated 3M cells and can be rescued by wild-type, but not by 3M patient-derived CUL7 mutants. Depletion of either OBSL1 or CCDC8 results in defects and sensitizes cells to microtubule damage similarly to loss of CUL7 function. Microtubule damage reduces the level of CCDC8 that is required for the centrosomal localization of CUL7. We propose that CUL7, OBSL1, and CCDC8 proteins form a 3M complex that functions in maintaining microtubule and genome integrity and normal development.
Asunto(s)
Proteínas Portadoras/metabolismo , Proteínas Cullin/metabolismo , Proteínas del Citoesqueleto/metabolismo , Inestabilidad Genómica , Microtúbulos/metabolismo , Línea Celular Tumoral , Centrosoma/metabolismo , Proteínas Cullin/genética , Enanismo/genética , Proteínas F-Box/metabolismo , Genoma Humano , Células HEK293 , Humanos , Hipotonía Muscular/genética , Mutación Missense , Transporte de Proteínas , Huso Acromático/metabolismo , Columna Vertebral/anomalíasRESUMEN
The Cullin 9 (CUL9) gene encodes a putative E3 ligase that localizes in the cytoplasm. Cul9 null mice develop spontaneous tumors in multiple organs; however, both the cellular and the molecular mechanisms of CUL9 in tumor suppression are currently unknown. We show here that deletion of Cul9 leads to abnormal nuclear morphology, increased DNA damage, and aneuploidy. CUL9 knockdown rescues the microtubule and mitosis defects in cells depleted for CUL7 or OBSL1, two genes that are mutated in a mutually exclusive manner in 3M growth retardation syndrome and function in microtubule dynamics. CUL9 promotes the ubiquitylation and degradation of survivin and is inhibited by CUL7. Depletion of CUL7 decreases survivin level, and overexpression of survivin rescues the defects caused by CUL7 depletion. We propose a 3M-CUL9-survivin pathway in maintaining microtubule and genome integrity, normal development, and tumor suppression.
Asunto(s)
Proteínas Cullin/fisiología , Inestabilidad Genómica , Proteínas Inhibidoras de la Apoptosis/metabolismo , Proteínas Represoras/metabolismo , Ubiquitinación , Aneuploidia , Animales , Muerte Celular , Proteínas Cullin/genética , Proteínas Cullin/metabolismo , Técnicas de Silenciamiento del Gen , Genes Supresores de Tumor , Células HCT116 , Humanos , Hígado/patología , Ratones , Ratones Noqueados , Complejos Multiproteicos/fisiología , Poliploidía , Multimerización de Proteína , SurvivinRESUMEN
Current preclinical evaluations of nanoparticle taxanes have focused on the effect of nanoparticle size and shape on the efficacy and toxicity. It is generally assumed that nanoparticle therapeutics have the same cellular response on tumor and normal cells as their small molecule counterparts. Here, we show that nanoparticle taxanes can mediate cellular effects distinct from that of small molecule taxanes at the sub-therapeutic dose range. Cells that are exposed to two polymeric nanoparticle formulations of docetaxel were found to undergo a different cell cycle and cell fate than those of cells that were exposed to small molecule docetaxel. Our results suggest that nanoparticle formulation of therapeutics can affect the therapeutic effect of its cargo. FROM THE CLINICAL EDITOR: This study investigates the differences between subtherapeutic doses of docetaxel applied as small molecules vs. nanoparticle formulations, demonstrating differential effects on the cell cycle and overall cell fate. The study suggests that the carrier may change the therapeutic effects of its cargo, which has important implications on future research.
Asunto(s)
Antineoplásicos/química , Sistemas de Liberación de Medicamentos , Nanopartículas/química , Taxoides/química , Línea Celular Tumoral , Docetaxel , Fibroblastos/metabolismo , Proteínas Fluorescentes Verdes/química , Humanos , Micelas , Nanomedicina , Tamaño de la Partícula , Polímeros/química , Taxoides/administración & dosificaciónRESUMEN
Tumor cells frequently exhibit widespread epigenetic aberrations that significantly alter the repertoire of expressed proteins. In particular, it has been known for nearly 25 years that tumors frequently reactivate genes whose expression is typically restricted to germ cells. These gene products are classified as cancer/testis antigens (CTAs) owing to their biased expression pattern and their immunogenicity in cancer patients. While these genes have been pursued as targets for anticancer vaccines, whether these reactivated testis proteins have roles in supporting tumorigenic features is less studied. Recent evidence now indicates that these proteins can be directly employed by the tumor cell regulatory environment to support cell-autonomous behaviors. Here, we review the history of the CTA field and present recent findings indicating that CTAs can play functional roles in supporting tumorigenesis.