Douglas E. Friesen
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Douglas E. Friesen has a total of 10 co-authors. Here are the top co-authors by number of shared publications:
- Jack A. Tuszynski
Department of Physics, University of Alberta, 11335 Saskatchewan Dr NW, Edmonton, AB T6G 2M9, Canada
4 shared publications - Cornelia Wenger
Institute of Biophysics and Biomedical Engineering, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
1 shared publication - Edward A Rietman
Center of Cancer Systems Biology, GeneSys Research Institute, Tufts University School of Medicine, Boston 02142, USA
1 shared publication - Jordane Preto
Department of Physics and Department of Oncology Cross Cancer Institute 3-336 T6G 1Z2 Edmonton AB Canada
1 shared publication - Lynn Hlatky
Center of Cancer Systems Biology, Tufts University School of Medicine, Boston, MA, USA
1 shared publication - Nancy J. Woolf
University of California
1 shared publication
Latest Publications
- Open Access
- 12 November 2016
- Published by MDPI AG in International Journal of Environmental Research and Public Health
- Vol. 13 (11) , 1128
An Overview of Sub-Cellular Mechanisms Involved in the Action of TTFields
Long-standing research on electric and electromagnetic field interactions with biological cells and their subcellular structures has mainly focused on the low- and high-frequency regimes. Biological effects at intermediate frequencies between 100 and 300 kHz have been recently discovered and applied to cancer cells as a therapeutic modality called Tumor Treating Fields (TTFields). TTFields are clinically applied to disrupt cell division, primarily for the treatment of glioblastoma multiforme (GBM). In this review, we provide an assessment of possible physical interactions between 100 kHz range alternating electric fields and biological cells in general and their nano-scale subcellular structures in particular. This is intended to mechanistically elucidate the observed strong disruptive effects in cancer cells. Computational models of isolated cells subject to TTFields predict that for intermediate frequencies the intracellular electric field strength significantly increases and that peak dielectrophoretic forces develop in dividing cells. These findings are in agreement with in vitro observations of TTFields’ disruptive effects on cellular function. We conclude that the most likely candidates to provide a quantitative explanation of these effects are ionic condensation waves around microtubules as well as dielectrophoretic effects on the dipole moments of microtubules. A less likely possibility is the involvement of actin filaments or ion channels.
- 12 November 2016
- Published by MDPI AG in International Journal of Environmental Research and Public Health
- Vol. 13 (11) , 1128
Open AccessAn Overview of Sub-Cellular Mechanisms Involved in the Action of TTFields
Long-standing research on electric and electromagnetic field interactions with biological cells and their subcellular structures has mainly focused on the low- and high-frequency regimes. Biological effects at intermediate frequencies between 100 and 300 kHz have been recently discovered and applied to cancer cells as a therapeutic modality called Tumor Treating Fields (TTFields). TTFields are clinically applied to disrupt cell division, primarily for the treatment of glioblastoma multiforme (GBM). In this review, we provide an assessment of possible physical interactions between 100 kHz range alternating electric fields and biological cells in general and their nano-scale subcellular structures in particular. This is intended to mechanistically elucidate the observed strong disruptive effects in cancer cells. Computational models of isolated cells subject to TTFields predict that for intermediate frequencies the intracellular electric field strength significantly increases and that peak dielectrophoretic forces develop in dividing cells. These findings are in agreement with in vitro observations of TTFields’ disruptive effects on cellular function. We conclude that the most likely candidates to provide a quantitative explanation of these effects are ionic condensation waves around microtubules as well as dielectrophoretic effects on the dipole moments of microtubules. A less likely possibility is the involvement of actin filaments or ion channels.
- Open Access
- 15 September 2015
- Published by Springer Nature in Theoretical Biology and Medical Modelling
- Vol. 12 (1) , 1-18
Modeling the energetic cost of cancer as a result of altered energy metabolism: implications for cachexia
Cachexia affects most patients with incurable cancer. We hypothesize that in metastatic cancer the mass of the tumor as well as its level of anaerobic energy metabolism play a critical role in describing its energetic cost, which results in elevated resting energy expenditure and glucose utilization, leading to cachexia. Prior models of cancer cachexia may have underestimated the specific energetic cost of cancer as they have not taken the range of tumor mass and anaerobic energy metabolism fully into account. We therefore modelled the energetic cost of cancer as a function of the percentage of energy the cancer produces anaerobically, based on resting energy expenditure, glucose turnover, glucose recycling, and oxygen consumption in cancer patients found in previous studies. Data from two clinical studies where tumor burden was estimated and resting energy expenditure or oxygen consumption were measured lead to a broad range of estimates of tumor cost from 190 to 470 kcal/kg tumor/day. These values will vary based of the percentage of energy the cancer produces anaerobically (from 0 to 100 %), which in and of itself can alter the cost over a 2 to 3-fold range. In addition to the tumor cost/kg and the degree of anaerobic metabolism, the impact on a given individual patient will depend on tumor burden, which can exceed 1 kg in advanced metastatic disease. Considering these dimensions of tumor cost we are able to produce a 2-dimensional map of potential values, with an overall range of 100–1400 kcal/day. Quantifying the energetic cost of cancer may benefit an understanding of the tumor’s causation of cachexia. Our estimates of the range of tumor cost include values that are higher than prior estimates and suggest that in metastatic disease the tumor cost could be expected to eclipse attempts to stabilize energy balance through nutrition support or by drug therapies. Tumor mass and the percentage of anaerobic metabolism in the tumor contribute to the cost of the tumor on the body and potentially lead directly to negative energy balance and increased muscle wasting.
- 15 September 2015
- Published by Springer Nature in Theoretical Biology and Medical Modelling
- Vol. 12 (1) , 1-18
Open AccessModeling the energetic cost of cancer as a result of altered energy metabolism: implications for cachexia
Cachexia affects most patients with incurable cancer. We hypothesize that in metastatic cancer the mass of the tumor as well as its level of anaerobic energy metabolism play a critical role in describing its energetic cost, which results in elevated resting energy expenditure and glucose utilization, leading to cachexia. Prior models of cancer cachexia may have underestimated the specific energetic cost of cancer as they have not taken the range of tumor mass and anaerobic energy metabolism fully into account. We therefore modelled the energetic cost of cancer as a function of the percentage of energy the cancer produces anaerobically, based on resting energy expenditure, glucose turnover, glucose recycling, and oxygen consumption in cancer patients found in previous studies. Data from two clinical studies where tumor burden was estimated and resting energy expenditure or oxygen consumption were measured lead to a broad range of estimates of tumor cost from 190 to 470 kcal/kg tumor/day. These values will vary based of the percentage of energy the cancer produces anaerobically (from 0 to 100 %), which in and of itself can alter the cost over a 2 to 3-fold range. In addition to the tumor cost/kg and the degree of anaerobic metabolism, the impact on a given individual patient will depend on tumor burden, which can exceed 1 kg in advanced metastatic disease. Considering these dimensions of tumor cost we are able to produce a 2-dimensional map of potential values, with an overall range of 100–1400 kcal/day. Quantifying the energetic cost of cancer may benefit an understanding of the tumor’s causation of cachexia. Our estimates of the range of tumor cost include values that are higher than prior estimates and suggest that in metastatic disease the tumor cost could be expected to eclipse attempts to stabilize energy balance through nutrition support or by drug therapies. Tumor mass and the percentage of anaerobic metabolism in the tumor contribute to the cost of the tumor on the body and potentially lead directly to negative energy balance and increased muscle wasting.
- Open Access
- 10 June 2013
- Published by Springer Nature in Theoretical Biology and Medical Modelling
- Vol. 10 (1) , 1-39
An integrated multidisciplinary model describing initiation of cancer and the Warburg hypothesis
In this paper we propose a chemical physics mechanism for the initiation of the glycolytic switch commonly known as the Warburg hypothesis, whereby glycolytic activity terminating in lactate continues even in well-oxygenated cells. We show that this may result in cancer via mitotic failure, recasting the current conception of the Warburg effect as a metabolic dysregulation consequent to cancer, to a biophysical defect that may contribute to cancer initiation.
- 10 June 2013
- Published by Springer Nature in Theoretical Biology and Medical Modelling
- Vol. 10 (1) , 1-39
Open AccessAn integrated multidisciplinary model describing initiation of cancer and the Warburg hypothesis
In this paper we propose a chemical physics mechanism for the initiation of the glycolytic switch commonly known as the Warburg hypothesis, whereby glycolytic activity terminating in lactate continues even in well-oxygenated cells. We show that this may result in cancer via mitotic failure, recasting the current conception of the Warburg effect as a metabolic dysregulation consequent to cancer, to a biophysical defect that may contribute to cancer initiation.
- 3 December 2009
- Published by NeuroQuantology Journal in NeuroQuantology
- Vol. 8 (1)
Neuropsychiatric Illness: A Case for Impaired Neuroplasticity and Possible Quantum Processing Derailment in Microtubules
There is a great deal of evidence that cytoskeletal proteins, in particular microtubules, are dysfunctional in mental illnesses such as schizophrenia and affective disorder. Since cytoskeletal proteins are major arbitrators of neuroplasticity, this evidence fits with recent theories suggesting that neuroplasticity is compromised in mental illness and that the efficacy of antidepressant and antipsychotic drugs may depend, at least in part, on their ability to enhance neuroplasticity. Quantum theories of mind, particularly those implementing information processing in microtubules, are useful on many levels. Quantum theories attempt to explain the more enigmatic features of mind, some of which are disrupted in mental illness. Quantum information processing theories also attempt to link molecular events at the atomic level to higher cognition. These approaches are highly ambitious, and multiple potential obstacles abound as a consequence of working in largely uncharted territory.
- 3 December 2009
- Published by NeuroQuantology Journal in NeuroQuantology
- Vol. 8 (1)
Neuropsychiatric Illness: A Case for Impaired Neuroplasticity and Possible Quantum Processing Derailment in Microtubules
There is a great deal of evidence that cytoskeletal proteins, in particular microtubules, are dysfunctional in mental illnesses such as schizophrenia and affective disorder. Since cytoskeletal proteins are major arbitrators of neuroplasticity, this evidence fits with recent theories suggesting that neuroplasticity is compromised in mental illness and that the efficacy of antidepressant and antipsychotic drugs may depend, at least in part, on their ability to enhance neuroplasticity. Quantum theories of mind, particularly those implementing information processing in microtubules, are useful on many levels. Quantum theories attempt to explain the more enigmatic features of mind, some of which are disrupted in mental illness. Quantum information processing theories also attempt to link molecular events at the atomic level to higher cognition. These approaches are highly ambitious, and multiple potential obstacles abound as a consequence of working in largely uncharted territory.