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PD-1/PD-L1 and DNA Damage Response in Cancer. Cells 2023; 12:cells12040530. [PMID: 36831197 PMCID: PMC9954559 DOI: 10.3390/cells12040530] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 01/29/2023] [Accepted: 02/02/2023] [Indexed: 02/09/2023] Open
Abstract
The application of immunotherapy for cancer treatment is rapidly becoming more widespread. Immunotherapeutic agents are frequently combined with various types of treatments to obtain a more durable antitumor clinical response in patients who have developed resistance to monotherapy. Chemotherapeutic drugs that induce DNA damage and trigger DNA damage response (DDR) frequently induce an increase in the expression of the programmed death ligand-1 (PD-L1) that can be employed by cancer cells to avoid immune surveillance. PD-L1 exposed on cancer cells can in turn be targeted to re-establish the immune-reactive tumor microenvironment, which ultimately increases the tumor's susceptibility to combined therapies. Here we review the recent advances in how the DDR regulates PD-L1 expression and point out the effect of etoposide, irinotecan, and platinum compounds on the anti-tumor immune response.
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de Campos Nebel M, Palmitelli M, Pérez Maturo J, González-Cid M. Alternative end-joining originates stable chromosome aberrations induced by etoposide during targeted inhibition of DNA-PKcs in ATM-deficient tumor cells. Chromosome Res 2022; 30:459-476. [PMID: 35604590 DOI: 10.1007/s10577-022-09700-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/29/2022] [Accepted: 05/09/2022] [Indexed: 01/25/2023]
Abstract
ATM and DNA-PKcs coordinate the DNA damage response at multiple levels following the exposure to chemotherapy. The Topoisomerase II poison etoposide (ETO) is an effective chemotherapeutic agent that induces DNA double-strand breaks (DSB), but it is responsible from the chromosomal rearrangements frequently found in therapy-related secondary tumors. Targeted inhibition of DNA-PKcs in ATM-defective tumors combined with radio- or chemotherapy has been proposed as relevant therapies. Here, we explored the DNA repair mechanisms and the genetic consequences of targeting the non-oncogenic addiction to DNA-PKcs of ATM-defective tumor cells after exposure to ETO. We demonstrated that chemical inhibition of DNA-PKcs followed by treatment with ETO resulted in the accumulation of chromatid breaks and decreased mitotic index in both A-T cells and ATM-knocked-down (ATMkd) tumor cells. The HR repair process in DNA-PKcs-inhibited ATMkd cells amplified the RAD51 foci number, with no correlated increase in sister chromatid exchanges. The analysis of post-mitotic DNA lesions presented an augmented number of persistent unresolved DSB, without alterations in the cell cycle progression. Long-term examination of chromosome aberrations revealed a strikingly high number of chromatid and chromosome exchanges. By using genetic and pharmacological abrogation of PARP-1, we demonstrated that alternative end-joining (alt-EJ) repair pathway is responsible for those chromosome abnormalities generated by limiting c-NHEJ activities during directed inhibition of DNA-PKcs in ATM-deficient cells. Targeting the non-oncogenic addiction to DNA-PKcs of ATM-defective tumors stimulates the DSB repair by alt-EJ, which is liable for the origin of cells carrying stable chromosome aberrations that may eventually restrict the therapeutic strategy.
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Affiliation(s)
- Marcelo de Campos Nebel
- Laboratorio de Mutagénesis, Instituto de Medicina Experimental (IMEX), CONICET-Academia Nacional de Medicina, Buenos Aires, Argentina.
| | - Micaela Palmitelli
- Laboratorio de Mutagénesis, Instituto de Medicina Experimental (IMEX), CONICET-Academia Nacional de Medicina, Buenos Aires, Argentina
| | - Josefina Pérez Maturo
- Programa de Medicina de Precisión Y Genómica Clínica, Facultad de Ciencias Biomédicas,, Instituto de Investigaciones en Medicina Traslacional, Universidad Austral-CONICET, Pilar, Argentina
- Consultorio Y Laboratorio de Neurogenética, Facultad de Medicina, Centro Universitario de Neurología "José María Ramos Mejía" Y División Neurología, Hospital J.M. Ramos Mejía, Universidad de Buenos Aires, Buenos Aires,, Argentina
| | - Marcela González-Cid
- Laboratorio de Mutagénesis, Instituto de Medicina Experimental (IMEX), CONICET-Academia Nacional de Medicina, Buenos Aires, Argentina
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Wang W, Chen J, Luo D, Chen J, Xu H, Chen W, Wang Y. Effects of Low-Intensity Pulsed Ultrasound on Myelosuppression of Rats Induced by Chemotherapy Drugs With Cell Cycle Specificity. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2021; 40:1811-1822. [PMID: 33174633 DOI: 10.1002/jum.15562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 10/03/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVES To explore the ameliorating effects of low-intensity pulsed ultrasound (LIPUS) on Sprague Dawley rat myelosuppression induced by cell cycle specificity drugs (docetaxel, mitotic phase sensitive; and etoposide, gap 2 phase sensitive). METHODS Rats were respectively administered docetaxel (100 mg/kg) or etoposide (110 mg/kg) by intraperitoneal injection for 4 consecutive days. Then the rats were divided randomly into a LIPUS group and a non-LIPUS group. In the LIPUS group, the right femoral metaphysis of rats was treated by LIPUS (acoustic intensity, 200 mW/cm2 ; frequency, 0.3 MHz; and duty cycle, 20%) for 20 minutes on 7 consecutive days from day 5. The rats of the non-LIPUS group were treated without ultrasound output. A blood cell count, an enzyme-linked immunosorbent assay, a real-time quantitative polymerase chain reaction, and hematoxylin-eosin staining were applied to detect the results. RESULTS Low-intensity pulsed ultrasound significantly promoted the counts of bone marrow nucleated cells, white blood cells, immunoglobulin A (IgA), IgG, granulocyte colony-stimulating factor, stem cell factor, and intercellular cell adhesion molecule 1 and reduced the counts of vascular cell adhesion molecule 1 whether in the docetaxel or etoposide group (P < .05). Low-intensity pulsed ultrasound only increased the expression level of IgM in the docetaxel group but decreased the level of interleukin 6 in the etoposide group (P < .05). CONCLUSIONS Low-intensity pulsed ultrasound has potential to be a noninvasive treatment for myelosuppression caused by different cell cycle-sensitive chemotherapy drugs.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Junlin Chen
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Dong Luo
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Jinyun Chen
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Haopeng Xu
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Wenzhi Chen
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
| | - Yan Wang
- State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing, China
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Scarpa M, Kapoor S, Tvedte ES, Doshi KA, Zou YS, Singh P, Lee JK, Chatterjee A, Ali MKM, Bromley RE, Hotopp JCD, Rassool FV, Baer MR. Pim kinase inhibitor co-treatment decreases alternative non-homologous end-joining DNA repair and genomic instability induced by topoisomerase 2 inhibitors in cells with FLT3 internal tandem duplication. Oncotarget 2021; 12:1763-1779. [PMID: 34504649 PMCID: PMC8416564 DOI: 10.18632/oncotarget.28042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/28/2021] [Indexed: 01/11/2023] Open
Abstract
Acute myeloid leukemia (AML) with fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) relapses with new chromosome abnormalities following chemotherapy, implicating genomic instability. Error-prone alternative non-homologous end-joining (Alt-NHEJ) DNA double-strand break (DSB) repair is upregulated in FLT3-ITD-expresssing cells, driven by c-Myc. The serine/threonine kinase Pim-1 is upregulated downstream of FLT3-ITD, and inhibiting Pim increases topoisomerase 2 (TOP2) inhibitor chemotherapy drug induction of DNA DSBs and apoptosis. We hypothesized that Pim inhibition increases DNA DSBs by downregulating Alt-NHEJ, also decreasing genomic instability. Alt-NHEJ activity, measured with a green fluorescent reporter construct, increased in FLT3-ITD-transfected Ba/F3-ITD cells treated with TOP2 inhibitors, and this increase was abrogated by Pim kinase inhibitor AZD1208 co-treatment. TOP2 inhibitor and AZD1208 co-treatment downregulated cellular and nuclear expression of c-Myc and Alt-NHEJ repair pathway proteins DNA polymerase θ, DNA ligase 3 and XRCC1 in FLT3-ITD cell lines and AML patient blasts. ALT-NHEJ protein downregulation was preceded by c-Myc downregulation, inhibited by c-Myc overexpression and induced by c-Myc knockdown or inhibition. TOP2 inhibitor treatment increased chromosome breaks in metaphase spreads in FLT3-ITD-expressing cells, and AZD1208 co-treatment abrogated these increases. Thus Pim kinase inhibitor co-treatment both enhances TOP2 inhibitor cytotoxicity and decreases TOP2 inhibitor-induced genomic instability in cells with FLT3-ITD.
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Affiliation(s)
- Mario Scarpa
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shivani Kapoor
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | | | - Kshama A. Doshi
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Ying S. Zou
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Prerna Singh
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Jonelle K. Lee
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
| | - Aditi Chatterjee
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Moaath K. Mustafa Ali
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | | | - Julie C. Dunning Hotopp
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Institute for Genome Sciences, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Feyruz V. Rassool
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Maria R. Baer
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
- Veterans Affairs Medical Center, Baltimore, MD, USA
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Kopa P, Macieja A, Gulbas I, Pastwa E, Poplawski T. Inhibition of DNA-PK potentiates the synergistic effect of NK314 and etoposide combination on human glioblastoma cells. Mol Biol Rep 2019; 47:67-76. [PMID: 31583565 DOI: 10.1007/s11033-019-05105-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022]
Abstract
Etoposide (VP-16) is the topoisomerase 2 (Top2) inhibitor used for treating of glioma patients however at high dose with serious side effects. It induces DNA double-strand breaks (DSBs). These DNA lesions are repaired by non-homologous DNA end joining (NHEJ) mediated by DNA-dependent protein kinase (DNA-PK). One possible approach to decrease the toxicity of etoposide is to reduce the dose while maintaining the anticancer potential. It could be achieved through combined therapy with other anticancer drugs. We have assumed that this objective can be obtained by (1) a parallel topo2 α inhibition and (2) sensitization of cancer cells to DSBs. In this work we investigated the effect of two Top2 inhibitors NK314 and VP-16 in glioma cell lines (MO59 K and MO59 J) sensitized by DNA-PK inhibitor, NU7441. Cytotoxic effect of VP-16, NK314 alone and in combination on human glioblastoma cell lines, was assessed by a colorimetric assay. Genotoxic effect of anticancer drugs in combination with NU7441 was assessed by comet assay. Cell cycle distribution and apoptosis were analysed by flow cytometry. Compared with VP-16 or NK314 alone, the combined treatment significantly inhibited cell proliferation. Combination treatment was associated with a strong accumulation of DSBs, modulated cell cycle phases distribution and apoptotic cell death. NU7441 potentiated these effects and additionally postponed DNA repair. Our findings suggest that NK314 could overcome resistance of MO59 cells to VP-16 and NU7441 could serve as sensitizer to VP-16/NK314 combined treatment. The combined tripartite approach of chemotherapy could reduce the overall toxicity associated with each individual therapy, while concomitantly enhancing the anticancer effect to treat human glioma cells. Thus, the use of a tripartite combinatorial approach could be promising and more efficacious than mono therapy or dual therapy to treat and increase the survival of the glioblastoma patients.
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Affiliation(s)
- Paulina Kopa
- Department of Immunopathology, Division of Allergology, Immunology and Immunopathology, Faculty of Biomedical Sciences and Postgraduate Training, Medical University of Lodz, Lodz, Poland
| | - Anna Macieja
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Izabela Gulbas
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Elzbieta Pastwa
- Functional Genomics & Proteomics Unit, ITSI-Biosciences, Johnstown, PA, USA
| | - Tomasz Poplawski
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.
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Limpose KL, Trego KS, Li Z, Leung SW, Sarker AH, Shah JA, Ramalingam SS, Werner EM, Dynan WS, Cooper PK, Corbett AH, Doetsch PW. Overexpression of the base excision repair NTHL1 glycosylase causes genomic instability and early cellular hallmarks of cancer. Nucleic Acids Res 2018; 46:4515-4532. [PMID: 29522130 PMCID: PMC5961185 DOI: 10.1093/nar/gky162] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 02/18/2018] [Accepted: 02/21/2018] [Indexed: 12/22/2022] Open
Abstract
Base excision repair (BER), which is initiated by DNA N-glycosylase proteins, is the frontline for repairing potentially mutagenic DNA base damage. The NTHL1 glycosylase, which excises DNA base damage caused by reactive oxygen species, is thought to be a tumor suppressor. However, in addition to NTHL1 loss-of-function mutations, our analysis of cancer genomic datasets reveals that NTHL1 frequently undergoes amplification or upregulation in some cancers. Whether NTHL1 overexpression could contribute to cancer phenotypes has not yet been explored. To address the functional consequences of NTHL1 overexpression, we employed transient overexpression. Both NTHL1 and a catalytically-dead NTHL1 (CATmut) induce DNA damage and genomic instability in non-transformed human bronchial epithelial cells (HBEC) when overexpressed. Strikingly, overexpression of either NTHL1 or CATmut causes replication stress signaling and a decrease in homologous recombination (HR). HBEC cells that overexpress NTHL1 or CATmut acquire the ability to grow in soft agar and exhibit loss of contact inhibition, suggesting that a mechanism independent of NTHL1 catalytic activity contributes to acquisition of cancer-related cellular phenotypes. We provide evidence that NTHL1 interacts with the multifunctional DNA repair protein XPG suggesting that interference with HR is a possible mechanism that contributes to acquisition of early cellular hallmarks of cancer.
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Affiliation(s)
- Kristin L Limpose
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
- Graduate Program in Cancer Biology, Emory University, Atlanta, GA 30322, USA
| | - Kelly S Trego
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Zhentian Li
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, USA
| | - Sara W Leung
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Altaf H Sarker
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jason A Shah
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Suresh S Ramalingam
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Erica M Werner
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - William S Dynan
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Priscilla K Cooper
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
- Laboratory of Genome Integrity and Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
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Lewis CW, Golsteyn RM. Cancer cells that survive checkpoint adaptation contain micronuclei that harbor damaged DNA. Cell Cycle 2016; 15:3131-3145. [PMID: 27636097 DOI: 10.1080/15384101.2016.1231287] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
We have examined the relationship between checkpoint adaptation (mitosis with damaged DNA) and micronuclei. Micronuclei in cancer cells are linked to genomic change, and may induce chromothripsis (chromosome shattering). We measured the cytotoxicity of the cancer drug cisplatin in M059K (glioma fibroblasts, IC50 15 μM). Nearly 100% of M059K cells were positive for histone γH2AX staining after 48 h treatment with a cytotoxic concentration of cisplatin. The proportion of micronucleated cells, as confirmed by microscopy using DAPI and lamin A/C staining, increased from 24% to 48%, and the total micronuclei in surviving cells accumulated over time. Promoting entry into mitosis with a checkpoint inhibitor increased the number of micronuclei in cells whereas blocking checkpoint adaptation with a Cdk inhibitor reduced the number of micronuclei. Interestingly, some micronuclei underwent asynchronous DNA replication, relative to the main nuclei, as measured by deoxy-bromo-uracil (BrdU) staining. These micronuclei stained positive for histone γH2AX, which was linked to DNA replication, suggesting that micronuclei arise from checkpoint adaptation and that micronuclei may continue to damage DNA. By contrast the normal cell line WI-38 did not undergo checkpoint adaptation when treated with cisplatin and did not show changes in micronuclei number. These data reveal that the production of micronuclei by checkpoint adaptation is part of a process that contributes to genomic change.
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Affiliation(s)
- Cody W Lewis
- a Cancer Cell Laboratory, Department of Biological Sciences, University of Lethbridge , Lethbridge , AB , Canada
| | - Roy M Golsteyn
- a Cancer Cell Laboratory, Department of Biological Sciences, University of Lethbridge , Lethbridge , AB , Canada
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Burke RT, Orth JD. Through the Looking Glass: Time-lapse Microscopy and Longitudinal Tracking of Single Cells to Study Anti-cancer Therapeutics. J Vis Exp 2016. [PMID: 27213923 DOI: 10.3791/53994] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The response of single cells to anti-cancer drugs contributes significantly in determining the population response, and therefore is a major contributing factor in the overall outcome. Immunoblotting, flow cytometry and fixed cell experiments are often used to study how cells respond to anti-cancer drugs. These methods are important, but they have several shortcomings. Variability in drug responses between cancer and normal cells, and between cells of different cancer origin, and transient and rare responses are difficult to understand using population averaging assays and without being able to directly track and analyze them longitudinally. The microscope is particularly well suited to image live cells. Advancements in technology enable us to routinely image cells at a resolution that enables not only cell tracking, but also the observation of a variety of cellular responses. We describe an approach in detail that allows for the continuous time-lapse imaging of cells during the drug response for essentially as long as desired, typically up to 96 hr. Using variations of the approach, cells can be monitored for weeks. With the employment of genetically encoded fluorescent biosensors numerous processes, pathways and responses can be followed. We show examples that include tracking and quantification of cell growth and cell cycle progression, chromosome dynamics, DNA damage, and cell death. We also discuss variations of the technique and its flexibility, and highlight some common pitfalls.
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Affiliation(s)
- Russell T Burke
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - James D Orth
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder;
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Zhang R, Zhu L, Zhang L, Xu A, Li Z, Xu Y, He P, Wu M, Wei F, Wang C. PTEN enhances G2/M arrest in etoposide-treated MCF‑7 cells through activation of the ATM pathway. Oncol Rep 2016; 35:2707-14. [PMID: 26986476 DOI: 10.3892/or.2016.4674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 12/27/2015] [Indexed: 11/06/2022] Open
Abstract
As an effective tumor suppressor, phosphatase and tensin homolog (PTEN) has attracted the increased attention of scientists. Recent studies have shown that PTEN plays unique roles in the DNA damage response (DDR) and can interact with the Chk1 pathway. However, little is known about how PTEN contributes to DDR through the ATM-Chk2 pathway. It is well-known that etoposide induces G2/M arrest in a variety of cell lines, including MCF-7 cells. The DNA damage-induced G2/M arrest results from the activation of protein kinase ataxia telangiectasia mutated (ATM), followed by the activation of Chk2 that subsequently inactivates CDC25C, resulting in G2/M arrest. In the present study, we assessed the contribution of PTEN to the etoposide-induced G2/M cell cycle arrest. PTEN was knocked down in MCF-7 cells by specific shRNA, and the effects of PTEN on the ATM-Chk2 pathway were investigated through various approaches. The results showed that knockdown of PTEN strongly antagonized ATM activation in response to etoposide treatment, and thereby reduced the phosphorylation level of ATM substrates, including H2AX, P53 and Chk2. Furthermore, depletion of PTEN reduced the etoposide-induced phosphorylation of CDC25C and strikingly compromised etoposide-induced G2/M arrest in the MCF-7 cells. Altogether, we demonstrated that PTEN plays a unique role in etoposide-induced G2/M arrest by facilitating the activation of the ATM pathway, and PTEN was required for the proper activation of checkpoints in response to DNA damage in MCF-7 cells.
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Affiliation(s)
- Ruopeng Zhang
- Department of Obstetrics and Gynecology, Shenzhen Maternity and Child Healthcare Hospital, Affiliated to Southern Medical University, Longgang, Shenzhen, Guangdong 518028, P.R. China
| | - Li Zhu
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Lirong Zhang
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Anli Xu
- Department of Reproductive Medicine, Affiliated Hospital of Dali University, Dali, Yunnan 671000, P.R. China
| | - Zhengwei Li
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Yijuan Xu
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Pei He
- Clinical Medicine College of Dali University, Dali, Yunnan 671000, P.R. China
| | - Maoqing Wu
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Fengxiang Wei
- The Genetics Laboratory, Shenzhen Longgang District Maternity and Child Healthcare Hospital, Longgang, Shenzhen, Guangdong 518028, P.R. China
| | - Chenhong Wang
- Department of Obstetrics and Gynecology, Shenzhen Maternity and Child Healthcare Hospital, Affiliated to Southern Medical University, Longgang, Shenzhen, Guangdong 518028, P.R. China
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