RESUMO
DNA replication stress, caused by various endogenous and exogenous agents, halt or stall DNA replication progression. Cells have developed diverse mechanisms to tolerate and overcome replication stress, enabling them to continue replication. One effective strategy to overcome stalled replication involves skipping the DNA lesion using a specialized polymerase known as PrimPol, which reinitiates DNA synthesis downstream of the damage. However, the mechanism regulating PrimPol repriming is largely unclear. In this study, we observe that knockdown of STN1 or CTC1, components of the CTC1/STN1/TEN1 complex, leads to enhanced replication progression following UV exposure. We find that such increased replication is dependent on PrimPol, and PrimPol recruitment to stalled forks increases upon CST depletion. Moreover, we find that p21 is upregulated in STN1-depleted cells in a p53-independent manner, and p21 depletion restores normal replication rates caused by STN1 deficiency. We identify that p21 interacts with PrimPol, and STN1 depletion stimulates p21-PrimPol interaction and facilitates PrimPol recruitment to stalled forks. Our findings reveal a previously undescribed interplay between CST, PrimPol and p21 in promoting repriming in response to stalled replication, and shed light on the regulation of PrimPol repriming at stalled forks.
Assuntos
Inibidor de Quinase Dependente de Ciclina p21 , DNA Primase , Replicação do DNA , DNA Polimerase Dirigida por DNA , Enzimas Multifuncionais , Proteínas de Ligação a Telômeros , Raios Ultravioleta , Humanos , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/genética , DNA Primase/metabolismo , DNA Primase/genética , DNA Polimerase Dirigida por DNA/metabolismo , DNA Polimerase Dirigida por DNA/genética , Proteínas de Ligação a Telômeros/metabolismo , Proteínas de Ligação a Telômeros/genética , Enzimas Multifuncionais/genética , Enzimas Multifuncionais/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Proteína Supressora de Tumor p53/genética , Dano ao DNARESUMO
The immune system interacts with cancer cells in multiple intricate ways that can shield the host against hyper-proliferation but can also contribute to malignancy. Understanding the protective roles of the immune system in its interaction with cancer cells can help device new and alternate therapeutic strategies. Many immunotherapeutic methodologies, including adaptive cancer therapy, cancer peptide vaccines, monoclonal antibodies, and immune checkpoint treatment, have transformed the traditional cancer treatment landscape. However, many questions remain unaddressed. The development of personalized combination therapy and neoantigen-based cancer vaccines would be the avant-garde approach to cancer treatment. Desirable chemotherapy should be durable, safe, and target-specific. Managing both tumor (intrinsic factors) and its microenvironment (extrinsic factors) are critical for successful immunotherapy. This review describes current approaches and their advancement related to monoclonal antibody-related clinical trials, new cytokine therapy, a checkpoint inhibitor, adoptive T cell therapy, cancer vaccine, and oncolytic virus.
Assuntos
Vacinas Anticâncer , Neoplasias , Anticorpos Monoclonais/uso terapêutico , Vacinas Anticâncer/uso terapêutico , Citocinas , Humanos , Fatores Imunológicos , Imunoterapia/métodos , Imunoterapia Adotiva , Neoplasias/tratamento farmacológico , Microambiente TumoralRESUMO
Telomerase is a specialized reverse transcriptase/terminal transferase enzyme that adds telomeric repeat sequences at the extreme end of a newly replicated chromosome. Apart from telomere lengthening, telomerase has many extracurricular activities. Telomerase is known to regulate the expression of many genes and helps in cancer progression and epithelial-to-mesenchymal transitions (EMTs). We have previously reported that human telomerase reverse transcriptase (hTERT) regulates the expression of plasminogen activator such as urokinase-type plasminogen activator (uPA) in cancer cells following a genome-wide transcriptomic study. Here, we present data substantiating these results in terms of real-time assays, western blots, and immunofluorescence. Another aim of this study is to find out the possible mechanism by which hTERT regulates the expression of plasminogen activators. We have used some molecular biology techniques such as quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence and some assays such as wound healing assay and colony formation assay to solve this question. In this study, we show a positive association between hTERT and uPA. We also demonstrate that hTERT enhances uPA expression concomitant with EMT. Knocking down of hTERT reduces uPA expression as well as reverses EMT in cancer cells. We have also found that uPA is a transforming growth factor beta (TGF-ß)-induced protein. Our observations establish that TGF-ß-induced uPA expression is hTERT dependent.
Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Membrana/genética , Osteoblastos/efeitos dos fármacos , Receptores de Ativador de Plasminogênio Tipo Uroquinase/genética , Telomerase/genética , Fator de Crescimento Transformador beta/farmacologia , Células A549 , Antígenos CD/genética , Antígenos CD/metabolismo , Caderinas/genética , Caderinas/metabolismo , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Transição Epitelial-Mesenquimal/genética , Células HeLa , Humanos , Proteínas de Membrana/metabolismo , Osteoblastos/metabolismo , Osteoblastos/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Receptores de Ativador de Plasminogênio Tipo Uroquinase/metabolismo , Transdução de Sinais , Telomerase/antagonistas & inibidores , Telomerase/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Vimentina/genética , Vimentina/metabolismo , beta Catenina/genética , beta Catenina/metabolismoRESUMO
Telomerase complex maintains the length of the telome, cbre, and protects erosion of the physical ends of the eukaryotic chromosome in all actively dividing cells including cancer cells. Telomerase activation extends the lifespan of cells in culture by maintaining the length of the telomere. Compared to terminally differentiated somatic cells, telomerase activity remains high in over 90% of cancer cells. It has now become clear that the role of telomerase is much more complex than just telomere lengthening. The remaining 10% of cancers deploy ALT (alternative lengthening of telomeres) pathway to maintain telomere length. Telomerase inhibitors offer a good therapeutic option. Also, telomerase-associated molecules can be targeted provided their roles are clearly established. In any case, it is necessary to understand the major role of telomerase in cancer cells. Many studies have already been done to explore gene profiling of a telomerase positive cell by knocking down expression of hTERT (telomerase reverse transcriptase). To complement these studies, we performed global gene profiling of a telomerase negative cell by ectopically expressing hTERT and studied changes in the global gene expression patterns. Analysis of microarray data for telomerase negative cells ectopically expressing telomerase showed 76 differentially regulated genes, out of which 39 genes were upregulated, and 37 were downregulated. Three upregulated genes such as TSPAN13, HMGCS2, DLX5, and three downregulated genes like DHRS2, CRYAB, and PDLIM1 were validated by real-time PCR. Knocking down of TSAPN13 in hTERT overexpressing U2OS cells enhanced the apoptosis of the cells. TSPAN13 knockdown in these cells suppressed mesenchymal properties and enhanced epithelial character.