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Karpińska K, Gielata M, Gwiazdowska A, Boryń Ł, Kobielak A. Catulin Based Reporter System to Track and Characterize the Population of Invasive Cancer Cells in the Head and Neck Squamous Cell Carcinoma. Int J Mol Sci 2021; 23:ijms23010140. [PMID: 35008571 PMCID: PMC8745103 DOI: 10.3390/ijms23010140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022] Open
Abstract
Head and neck squamous cell carcinoma (HNSCC) is an aggressive tumor with a poor prognosis due to late diagnosis and loco-regional metastasis. Partial or more complete epithelial-mesenchymal transition (EMT) plays a role in tumor progression; however, it remains a challenge to observe the EMT in vivo, due to its transient nature. Here, we developed a novel catulin promoter-based reporter system that allows us to isolate and characterize in vivo a small fraction of invasive cancer cells. The analyses of tumors revealed that Catulin-green fluorescent protein (GFP)-positive cells were enriched in clusters of cells at the tumor invasion front. A functional genomic study unveiled genes involved in cellular movement and invasion providing a molecular profile of HNSCC invasive cells. This profile overlapped partially with the expression of signature genes related to the partial EMT available from the single cell analysis of human HNSCC specimens, highlighting the relevance of our data to the clinical disease progression state. Interestingly, we also observed upregulations of genes involved in axonal guidance-L1 cell adhesion molecule (L1CAM), neuropilin-1, semaphorins, and ephrins, indicating potential interactions of cancer cells and neuronal components of the stroma. Taken together, our data indicated that the catulin reporter system marked a population of invasive HNSCC cells with a molecular profile associated with cancer invasion.
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Affiliation(s)
- Kamila Karpińska
- Laboratory of the Molecular Biology of Cancer, Centre of New Technologies, University of Warsaw, 00-927 Warsaw, Poland; (K.K.); (M.G.); (A.G.)
| | - Mateusz Gielata
- Laboratory of the Molecular Biology of Cancer, Centre of New Technologies, University of Warsaw, 00-927 Warsaw, Poland; (K.K.); (M.G.); (A.G.)
| | - Aleksandra Gwiazdowska
- Laboratory of the Molecular Biology of Cancer, Centre of New Technologies, University of Warsaw, 00-927 Warsaw, Poland; (K.K.); (M.G.); (A.G.)
| | - Łukasz Boryń
- Laboratory of Stem Cells, Tissue Development and Regeneration, Centre of New Technologies, University of Warsaw, 00-927 Warsaw, Poland;
| | - Agnieszka Kobielak
- Laboratory of the Molecular Biology of Cancer, Centre of New Technologies, University of Warsaw, 00-927 Warsaw, Poland; (K.K.); (M.G.); (A.G.)
- Correspondence: ; Tel.: +48-22-55-43-735
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Riess C, Irmscher N, Salewski I, Strüder D, Classen CF, Große-Thie C, Junghanss C, Maletzki C. Cyclin-dependent kinase inhibitors in head and neck cancer and glioblastoma-backbone or add-on in immune-oncology? Cancer Metastasis Rev 2021; 40:153-171. [PMID: 33161487 PMCID: PMC7897202 DOI: 10.1007/s10555-020-09940-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022]
Abstract
Cyclin-dependent kinases (CDK) control the cell cycle and play a crucial role in oncogenesis. Pharmacologic inhibition of CDK has contributed to the recent clinical approval of dual CDK4/6 inhibitors for the treatment of breast and small cell lung cancer. While the anticancer cell effects of CDK inhibitors are well-established, preclinical and early clinical studies describe additional mechanisms of action such as chemo- and radiosensitization or immune stimulation. The latter offers great potential to incorporate CDK inhibitors in immune-based treatments. However, dosing schedules and accurate timing of each combination partner need to be respected to prevent immune escape and resistance. In this review, we provide a detailed summary of CDK inhibitors in the two solid cancer types head and neck cancer and glioblastoma multiforme; it describes the molecular mechanisms of response vs. resistance and covers strategies to avoid resistance by the combination of immunotherapy or targeted therapy.
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Affiliation(s)
- Christin Riess
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany
- University Children's and Adolescents' Hospital, Rostock University Medical Center, Rostock, Germany
| | - Nina Irmscher
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany
| | - Inken Salewski
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany
| | - Daniel Strüder
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery "Otto Körner", Rostock University Medical Center, Rostock, Germany
| | - Carl-Friedrich Classen
- University Children's and Adolescents' Hospital, Rostock University Medical Center, Rostock, Germany
| | - Christina Große-Thie
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany
| | - Christian Junghanss
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany
| | - Claudia Maletzki
- Department of Medicine, Clinic III - Hematology, Oncology and Palliative Care, Rostock University Medical Center, Rostock, Germany.
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Yang J, Xu QC, Wang ZY, Lu X, Pan LK, Wu J, Wang C. Integrated Analysis of an lncRNA-Associated ceRNA Network Reveals Potential Biomarkers for Hepatocellular Carcinoma. J Comput Biol 2020; 28:330-344. [PMID: 33185458 DOI: 10.1089/cmb.2019.0250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a common malignant tumor worldwide. In this study, we aimed to explore the potential biomarkers and key regulatory pathways related to HCC using integrated bioinformatic analysis and validation. The microarray data of GSE12717 and GSE54238 were downloaded from the Gene Expression Omnibus database. A competing endogenous RNA (ceRNA) network was constructed based on potential long-noncoding RNA (lncRNA)-microRNA (miRNA)-mRNA interactions. A total of 191 mRNAs, 8 miRNAs, and 5 lncRNAs were selected to construct the ceRNA network. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to predict their biological functions. The PI3K-Akt signaling pathway was significantly enriched. Kaplan-Meier survival analysis based on the Gene Expression Profiling Interactive Analysis (GEPIA) database was conducted for the weighted mRNAs and lncRNAs. The results showed that SRC, GMPS, CDK2, FEN1, EZH2, ZWINT, MTHFD1L, GINS2, and MAPKAPK5-AS1 were significantly upregulated in tumor tissues. The relative expression levels of these genes were significantly upregulated in HCC patients based on the StarBase database. For further validation, the expression levels of these genes were detected by real-time quantitative reverse transcription-polymerase chain reaction in 20 HCC tumor tissues and paired paracancerous tissues. Receiver operating characteristic analysis revealed that CDK2, MTHFD1L, SRC, ZWINT, and MAPKAPK5-AS1 had significant diagnostic value in HCC, but further studies are needed to explore their mechanisms in HCC.
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Affiliation(s)
- Jie Yang
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Qing-Chun Xu
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Zhen-Yu Wang
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Xun Lu
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Liu-Kui Pan
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Jun Wu
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
| | - Chen Wang
- Department of Emergency Surgery, The Second People's Hospital of Wuhu, Wuhu, China
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Cui Y, Lu C, Zhang Z, Mao A, Feng L, Fu L, Gu F, Ma X, He D. A Long Non-coding RNA Lnc712 Regulates Breast Cancer Cell Proliferation. Int J Biol Sci 2020; 16:162-171. [PMID: 31892853 PMCID: PMC6930380 DOI: 10.7150/ijbs.36429] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/29/2019] [Indexed: 12/22/2022] Open
Abstract
Great quantity of intergenic noncoding RNAs (lncRNAs) have been identified in the mammalian genome and involved in various biological processes, especially in the development and metastasis of cancer. In this study, we identified one lncRNA, lncRNA NONHSAT028712 (Lnc712), was highly expressed in breast cancer cell lines and tissues based on microarray screening. Knockdown of Lnc712 largely inhibited breast cancer cell proliferation. Mechanistically, Lnc712 bound specifically to heat-shock protein 90 (HSP90). Interaction between Lnc712 and HSP90 is required for HSP90 binding to cell division cycle 37 (Cdc37). The Lnc712/HSP90/Cdc37 complex regulated cyclin-dependent kinase 2 (CDK2) activation and then triggered breast cancer cell proliferation. In summary, our results identified a new lncRNA regulate breast cancer proliferation though interaction with HSP90.
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Affiliation(s)
- Yue Cui
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Chunxiao Lu
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Zhiming Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Aiqin Mao
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Lei Feng
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Li Fu
- Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.,✉ Corresponding authors: Dongxu He, Ph.D. School of Food Science and Technology, Jiangnan University, Wuxi, China. ; Xin Ma, Ph.D. Wuxi School of Medicine, Jiangnan University, Wuxi, China. ; Feng Gu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China. ; Li Fu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.
| | - Feng Gu
- Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.,✉ Corresponding authors: Dongxu He, Ph.D. School of Food Science and Technology, Jiangnan University, Wuxi, China. ; Xin Ma, Ph.D. Wuxi School of Medicine, Jiangnan University, Wuxi, China. ; Feng Gu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China. ; Li Fu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.
| | - Xin Ma
- Wuxi School of Medicine, Jiangnan University, Wuxi, China.,✉ Corresponding authors: Dongxu He, Ph.D. School of Food Science and Technology, Jiangnan University, Wuxi, China. ; Xin Ma, Ph.D. Wuxi School of Medicine, Jiangnan University, Wuxi, China. ; Feng Gu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China. ; Li Fu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.
| | - Dongxu He
- School of Food Science and Technology, Jiangnan University, Wuxi, China.,✉ Corresponding authors: Dongxu He, Ph.D. School of Food Science and Technology, Jiangnan University, Wuxi, China. ; Xin Ma, Ph.D. Wuxi School of Medicine, Jiangnan University, Wuxi, China. ; Feng Gu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China. ; Li Fu, M.D. Department of Breast Cancer Pathology and Research Laboratory, State Key Laboratory of Breast Cancer Research, Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China.
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Liu Q, Gao J, Zhao C, Guo Y, Wang S, Shen F, Xing X, Luo Y. To control or to be controlled? Dual roles of CDK2 in DNA damage and DNA damage response. DNA Repair (Amst) 2019; 85:102702. [PMID: 31731257 DOI: 10.1016/j.dnarep.2019.102702] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 09/09/2019] [Accepted: 09/13/2019] [Indexed: 02/04/2023]
Abstract
CDK2 (cyclin-dependent kinase 2), a member of the CDK family, has been shown to play a role in many cellular activities including cell cycle progression, apoptosis and senescence. Recently, accumulating evidence indicates that CDK2 is involved in DNA damage and DNA repair response (DDR). When DNA is damaged by internal or external genotoxic stresses, CDK2 activity is required for proper DNA repair in vivo and in vitro, whereas inactivation of CDK2 by siRNA techniques or by inhibitors could result in DNA damage and stimulate DDR. Hence, CDK2 seems to play dual roles in DNA damage and DDR. On one aspect, it is activated and stimulates DDR to repair DNA damage when DNA damage occurs; on the other hand, its inactivation directly leads to DNA damage and evokes DDR. Here, we describe the roles of CDK2 in DNA damage and DDR, and discuss the potential application of CDK2 inhibitors as anti-cancer agents.
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Affiliation(s)
- Qi Liu
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Jinlan Gao
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Chenyang Zhao
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Yingying Guo
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Shiquan Wang
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Fei Shen
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Xuesha Xing
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China
| | - Yang Luo
- The Research Center for Medical Genomics, Key Laboratory of Medical Cell Biology, Ministry of Education, School of Life Science, China Medical University, Shenyang, Liaoning Province, PR China.
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Braig F, Voigtlaender M, Schieferdecker A, Busch CJ, Laban S, Grob T, Kriegs M, Knecht R, Bokemeyer C, Binder M. Liquid biopsy monitoring uncovers acquired RAS-mediated resistance to cetuximab in a substantial proportion of patients with head and neck squamous cell carcinoma. Oncotarget 2018; 7:42988-42995. [PMID: 27119512 PMCID: PMC5190002 DOI: 10.18632/oncotarget.8943] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 03/29/2016] [Indexed: 11/30/2022] Open
Abstract
Resistance to epidermal growth factor receptor (EGFR)-targeted therapy is insufficiently understood in head and neck squamous cell carcinoma (HNSCC), entailing the lack of predictive biomarkers. Here, we studied resistance-mediating EGFR ectodomain and activating RAS mutations by next-generation sequencing (NGS) of cell lines and tumor tissue of cetuximab-naïve patients (46 cases, 12 cell lines), as well as liquid biopsies taken during and after cetuximab/platinum/5-fluorouracil treatment (20 cases). Tumors of cetuximab-naïve patients were unmutated, except for HRAS mutations in 4.3% of patients. Liquid biopsies revealed acquired KRAS, NRAS or HRAS mutations in more than one third of patients after cetuximab exposure. 46% of patients with on-treatment disease progression showed acquired RAS mutations, while no RAS mutations were found in the non-progressive subset of patients, indicating that acquisition of RAS mutant clones correlated significantly with clinical resistance (Chi square p=0.032). The emergence of mutations preceded clinical progression in half of the patients, with a maximum time from mutation detection to clinical progression of 16 weeks. RAS mutations account for acquired resistance to EGFR-targeting in a substantial proportion of HNSCC patients, even though these tumors are rarely mutated at baseline. Liquid biopsies may be used for mutational monitoring to guide treatment decisions.
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Affiliation(s)
- Friederike Braig
- Department of Oncology and Hematology with Sections Bone Marrow Transplant and Pneumology, Hubertus Wald Tumorzentrum / University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Minna Voigtlaender
- Department of Oncology and Hematology with Sections Bone Marrow Transplant and Pneumology, Hubertus Wald Tumorzentrum / University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Aneta Schieferdecker
- Department of Oncology and Hematology with Sections Bone Marrow Transplant and Pneumology, Hubertus Wald Tumorzentrum / University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Chia-Jung Busch
- Department of Otorhinolaryngology, Head and Neck Cancer Center of The University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Simon Laban
- Department of Otorhinolaryngology, Head and Neck Cancer Center of The University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany.,Department of Otorhinolaryngology and Head and Neck Surgery, Ulm University Medical Center, Ulm, Germany
| | - Tobias Grob
- Department of Pathology, University Medical Center Hamburg, Hamburg, Germany
| | - Malte Kriegs
- Laboratory for Radiobiology and Experimental Radiooncology, Head and Neck Cancer Center of The University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Rainald Knecht
- Department of Otorhinolaryngology, Head and Neck Cancer Center of The University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Carsten Bokemeyer
- Department of Oncology and Hematology with Sections Bone Marrow Transplant and Pneumology, Hubertus Wald Tumorzentrum / University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
| | - Mascha Binder
- Department of Oncology and Hematology with Sections Bone Marrow Transplant and Pneumology, Hubertus Wald Tumorzentrum / University Cancer Center Hamburg, University Medical Center Hamburg, Hamburg, Germany
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Yamamoto VN, Thylur DS, Bauschard M, Schmale I, Sinha UK. Overcoming radioresistance in head and neck squamous cell carcinoma. Oral Oncol 2016; 63:44-51. [PMID: 27938999 DOI: 10.1016/j.oraloncology.2016.11.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 08/29/2016] [Accepted: 11/06/2016] [Indexed: 12/28/2022]
Abstract
Radiation therapy plays an essential role in the treatment of head and neck squamous cell carcinoma (HNSCC), yet therapeutic efficacy is hindered by treatment-associated toxicity and tumor recurrence. In comparison to other cancers, innovation has proved challenging, with the epidermal growth factor receptor (EGFR) antibody cetuximab being the only new radiosensitizing agent approved by the FDA in over half a century. This review examines the physiological mechanisms that contribute to radioresistance in HNSCC as well as preclinical and clinical data regarding novel radiosensitizing agents, with an emphasis on those with highest translational promise.
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Affiliation(s)
- Vicky N Yamamoto
- USC Tina and Rick Caruso Department of Otolaryngology-Head & Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
| | - David S Thylur
- USC Tina and Rick Caruso Department of Otolaryngology-Head & Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Michael Bauschard
- USC Tina and Rick Caruso Department of Otolaryngology-Head & Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Isaac Schmale
- Department of Otolaryngology-Head & Neck Surgery, University of Rochester Medical Center, Rochester, NY, United States
| | - Uttam K Sinha
- USC Tina and Rick Caruso Department of Otolaryngology-Head & Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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Unkel S, Belka C, Lauber K. On the analysis of clonogenic survival data: Statistical alternatives to the linear-quadratic model. Radiat Oncol 2016; 11:11. [PMID: 26822015 PMCID: PMC4730743 DOI: 10.1186/s13014-016-0584-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/05/2016] [Indexed: 12/28/2022] Open
Abstract
Background The most frequently used method to quantitatively describe the response to ionizing irradiation in terms of clonogenic survival is the linear-quadratic (LQ) model. In the LQ model, the logarithm of the surviving fraction is regressed linearly on the radiation dose by means of a second-degree polynomial. The ratio of the estimated parameters for the linear and quadratic term, respectively, represents the dose at which both terms have the same weight in the abrogation of clonogenic survival. This ratio is known as the α/β ratio. However, there are plausible scenarios in which the α/β ratio fails to sufficiently reflect differences between dose-response curves, for example when curves with similar α/β ratio but different overall steepness are being compared. In such situations, the interpretation of the LQ model is severely limited. Methods Colony formation assays were performed in order to measure the clonogenic survival of nine human pancreatic cancer cell lines and immortalized human pancreatic ductal epithelial cells upon irradiation at 0-10 Gy. The resulting dataset was subjected to LQ regression and non-linear log-logistic regression. Dimensionality reduction of the data was performed by cluster analysis and principal component analysis. Results Both the LQ model and the non-linear log-logistic regression model resulted in accurate approximations of the observed dose-response relationships in the dataset of clonogenic survival. However, in contrast to the LQ model the non-linear regression model allowed the discrimination of curves with different overall steepness but similar α/β ratio and revealed an improved goodness-of-fit. Additionally, the estimated parameters in the non-linear model exhibit a more direct interpretation than the α/β ratio. Dimensionality reduction of clonogenic survival data by means of cluster analysis was shown to be a useful tool for classifying radioresistant and sensitive cell lines. More quantitatively, principal component analysis allowed the extraction of scores of radioresistance, which displayed significant correlations with the estimated parameters of the regression models. Conclusions Undoubtedly, LQ regression is a robust method for the analysis of clonogenic survival data. Nevertheless, alternative approaches including non-linear regression and multivariate techniques such as cluster analysis and principal component analysis represent versatile tools for the extraction of parameters and/or scores of the cellular response towards ionizing irradiation with a more intuitive biological interpretation. The latter are highly informative for correlation analyses with other types of data, including functional genomics data that are increasingly beinggenerated.
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Affiliation(s)
- Steffen Unkel
- Department of Medical Statistics University Medical Centre, Georg-August-University Goettingen, Goettingen, Germany.
| | - Claus Belka
- Clinic for Radiotherapy and Radiation Oncology, LMU Munich, Munich, Germany. .,Clinic Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer', Helmholtz Center Munich, Munich, Germany.
| | - Kirsten Lauber
- Clinic for Radiotherapy and Radiation Oncology, LMU Munich, Munich, Germany. .,Clinic Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer', Helmholtz Center Munich, Munich, Germany.
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