Microtubules In Cancer Cells Research Articles

Temporal-Focusing Multiphoton Excitation Single-Molecule Localization Microscopy Using Spontaneously Blinking Fluorophores.

Single-molecule localization microscopy (SMLM) based on temporal-focusing multiphoton excitation (TFMPE) and single-wavelength excitation is used to visualize the three-dimensional (3D) distribution of spontaneously blinking fluorophore-labeled subcellular structures in a thick specimen with a nanoscale-level spatial resolution. To eliminate the photobleaching effect of unlocalized molecules in out-of-focus regions for improving the utilization rate of the photon budget in 3D SMLM imaging, SMLM with single-wavelength TFMPE achieves wide-field and axially confined two-photon excitation (TPE) of spontaneously blinking fluorophores. TPE spectral measurement of blinking fluorophores is then conducted through TFMPE imaging at a tunable excitation wavelength, yielding the optimal TPE wavelength for increasing the number of detected photons from a single blinking event during SMLM. Subsequently, the TPE fluorescence of blinking fluorophores is recorded to obtain a two-dimensional TFMPE-SMLM image of the microtubules in cancer cells with a localization precision of 18±6 nm and an overall imaging resolution of approximately 51 nm, which is estimated based on the contribution of Nyquist resolution and localization precision. Combined with astigmatic imaging, the system is capable of 3D TFMPE-SMLM imaging of brain tissue section of a 5XFAD transgenic mouse with the pathological features of Alzheimer's disease, revealing the distribution of neurotoxic amyloid-beta peptide deposits.

Temporal‐Focusing Multiphoton Excitation Single‐Molecule Localization Microscopy Using Spontaneously Blinking Fluorophores

AbstractSingle‐molecule localization microscopy (SMLM) based on temporal‐focusing multiphoton excitation (TFMPE) and single‐wavelength excitation is used to visualize the three‐dimensional (3D) distribution of spontaneously blinking fluorophore‐labeled subcellular structures in a thick specimen with a nanoscale‐level spatial resolution. To eliminate the photobleaching effect of unlocalized molecules in out‐of‐focus regions for improving the utilization rate of the photon budget in 3D SMLM imaging, SMLM with single‐wavelength TFMPE achieves wide‐field and axially confined two‐photon excitation (TPE) of spontaneously blinking fluorophores. TPE spectral measurement of blinking fluorophores is then conducted through TFMPE imaging at a tunable excitation wavelength, yielding the optimal TPE wavelength for increasing the number of detected photons from a single blinking event during SMLM. Subsequently, the TPE fluorescence of blinking fluorophores is recorded to obtain a two‐dimensional TFMPE‐SMLM image of the microtubules in cancer cells with a localization precision of 18±6 nm and an overall imaging resolution of approximately 51 nm, which is estimated based on the contribution of Nyquist resolution and localization precision. Combined with astigmatic imaging, the system is capable of 3D TFMPE‐SMLM imaging of brain tissue section of a 5XFAD transgenic mouse with the pathological features of Alzheimer's disease, revealing the distribution of neurotoxic amyloid‐beta peptide deposits.

Treatment with tumor-treating fields (TTFields) suppresses intercellular tunneling nanotube formation in vitro and upregulates immuno-oncologic biomarkers in vivo in malignant mesothelioma.

Disruption of intercellular communication within tumors is emerging as a novel potential strategy for cancer-directed therapy. Tumor-Treating Fields (TTFields) therapy is a treatment modality that has itself emerged over the past decade in active clinical use for patients with glioblastoma and malignant mesothelioma, based on the principle of using low-intensity alternating electric fields to disrupt microtubules in cancer cells undergoing mitosis. There is a need to identify other cellular and molecular effects of this treatment approach that could explain reported increased overall survival when TTFields are added to standard systemic agents. Tunneling nanotube (TNTs) are cell-contact-dependent filamentous-actin-based cellular protrusions that can connect two or more cells at long-range. They are upregulated in cancer, facilitating cell growth, differentiation, and in the case of invasive cancer phenotypes, a more chemoresistant phenotype. To determine whether TNTs present a potential therapeutic target for TTFields, we applied TTFields to malignant pleural mesothelioma (MPM) cells forming TNTs in vitro. TTFields at 1.0 V/cm significantly suppressed TNT formation in biphasic subtype MPM, but not sarcomatoid MPM, independent of effects on cell number. TTFields did not significantly affect function of TNTs assessed by measuring intercellular transport of mitochondrial cargo via intact TNTs. We further leveraged a spatial transcriptomic approach to characterize TTFields-induced changes to molecular profiles in vivo using an animal model of MPM. We discovered TTFields induced upregulation of immuno-oncologic biomarkers with simultaneous downregulation of pathways associated with cell hyperproliferation, invasion, and other critical regulators of oncogenic growth. Several molecular classes and pathways coincide with markers that we and others have found to be differentially expressed in cancer cell TNTs, including MPM specifically. We visualized short TNTs in the dense stromatous tumor material selected as regions of interest for spatial genomic assessment. Superimposing these regions of interest from spatial genomics over the plane of TNT clusters imaged in intact tissue is a new method that we designate Spatial Profiling of Tunneling nanoTubes (SPOTT). In sum, these results position TNTs as potential therapeutic targets for TTFields-directed cancer treatment strategies. We also identified the ability of TTFields to remodel the tumor microenvironment landscape at the molecular level, thereby presenting a potential novel strategy for converting tumors at the cellular level from 'cold' to 'hot' for potential response to immunotherapeutic drugs.

Development and Validation of a Novel UHPLC-MS/MS Method for the Quantification of Plinabulin in Plasma and Its Application in a Pharmacokinetic Study with Leukopenic Rats.

Plinabulin, a new antitumor drug developed from marine natural products that targets microtubules in cancer cells, is currently being tested in a phase III clinical study. Plinabulin has been clinically proven to be effective on leukopenia. However, to our knowledge, there are no reports investigating the pharmacokinetics of plinabulin in individuals with leukopenia and healthy individuals. In this study, we developed a rapid and sensitive UHPLC-MS/MS method for the detection of plinabulin for the first time. Using a novel cyclophosphamide-induced leukopenia model, we investigated the differences in the pharmacokinetic characteristics of plinabulin between rats with leukopenia and normal rats. Plinabulin and propranolol (IS) peaks were separated by gradient elution for a total run time of 5 min. The methodological validation showed a good accuracy (101.96-109.42%) and precision (RSD ≤ 5.37%) with the lower limit of quantification at 0.5 ng/mL. The recovery of plinabulin was between 91.99% and 109.75% (RSD ≤ 7.92%). The values of the area under the plasma concentration-time curve (AUC0-t) for leukopenia groups and control groups at doses of 0.5 mg/kg, 1 mg/kg, and 3 mg/kg were 148.89 ± 78.74 h·μg/L and 121.75 ± 31.56 h·μg/L; 318.15 ± 40.00 h·μg/L and 272.06 ± 42.85 h·μg/L; and 1432.43 ± 197.47 h·μg/L and 1337.12 ± 193.56 h·μg/L; respectively. The half-lives (t1/2s) of plinabulin were 0.49-0.72 h for leukopenia groups and 0.39-0.70 h for control groups at three doses, and the clearance rates (CLs) of plinabulin were 2.13-3.87 L/h/kg for leukopenia groups and 2.29-4.23 L/h/kg for control groups. Pharmacokinetic results showed that there was no significant pharmacokinetic difference between the normal group and the leukopenia group. Based on the power model, plinabulin exhibits a lack of dose proportionality over the dose range of 0.5-3 mg/kg after intravenous administration. This study provides guidance for the development of plinabulin as a potential candidate for the treatment of chemotherapy-induced leukopenia.

Bone morphogenetic protein receptor 2 inhibition destabilizes microtubules promoting the activation of lysosomes and cell death of lung cancer cells

BackgroundRecent studies have shown that bone morphogenetic protein receptor 2 (BMPR2) regulates cell survival signaling events in cancer cells independent of the BMP type 1 receptor (BMPR1) or the Smad-1/5 transcription factor. Mutations in BMPR2 trafficking proteins leads to overactive BMP signaling, which leads to neurological diseases caused by BMPR2 stabilization of the microtubules. It is not known whether BMPR2 regulates the microtubules in cancer cells and what effect this has on cell survival. It is also not known whether alterations in BMPR2 trafficking effects activity and response to BMPR2 inhibitors.MethodsWe utilized BMPR2 siRNA and the BMP receptor inhibitors JL5 and Ym155, which decrease BMPR2 signaling and cause its mislocalization to the cytoplasm. Using the JL5 resistant MDA-MD-468 cell line and sensitive lung cancer cell lines, we examined the effects of BMPR2 inhibition on BMPR2 mislocalization to the cytoplasm, microtubule destabilization, lysosome activation and cell survival.ResultsWe show that the inhibition of BMPR2 destabilizes the microtubules. Destabilization of the microtubules leads to the activation of the lysosomes. Activated lysosomes further decreases BMPR2 signaling by causing it to mislocalizated to the cytoplasm and/or lysosome for degradation. Inhibition of the lysosomes with chloroquine attenuates BMPR2 trafficking to the lysosome and cell death induced by BMPR2 inhibitors. Furthermore, in MDA-MD-468 cells that are resistant to JL5 induced cell death, BMPR2 was predominately located in the cytoplasm. BMPR2 failed to localize to the cytoplasm and/or lysosome following treatment with JL5 and did not destabilize the microtubules or activate the lysosomes.ConclusionsThese studies reveal that the inhibition of BMPR2 destabilizes the microtubules promoting cell death of cancer cells that involves the activation of the lysosomes. Resistance to small molecules targeting BMPR2 may occur if the BMPR2 is localized predominantly to the cytoplasm and/or fails to localize to the lysosome for degradation.9X69BgY5xE-34q9NhE79bcVideo

Evaluation of Cytotoxic Mechanisms of Clinacanthus Nutans Extracts in Cancer Cells

Background: The preparations of commercially available Clinacanthus nutans (Burm.F) Lindau (Acanthaceae) (CN) leaf are gaining attention as an alternative cancer treatment, particularly in South East Asia. Multiple studies have suggested that CN has potential anticancer activities; however, the mechanism of these activities has remained elusive. Objective: This study evaluated the cytotoxic mechanisms of CN extracts in cancer cells. Methods: CN extracts were prepared from either fresh or dried leaves, using different solvents. Cytotoxicity of CN extracts was tested on the A549 (lung cancer), HeLa (cervical cancer), MCF-7 (breast cancer) and MDA-MB-231 (breast cancer) cell lines using the MTT assay. Flow cytometry was used to assess changes in the cell cycle profile, while Western blotting was used to examine microtubule stability. Finally, the mode of cell death was investigated using the Annexin V-FITC Apoptosis Detection Kit. Results: Aqueous Fresh (AQF) extract was prepared to simulate the ethnomedicinal use of CN, and reduce cell viability of MCF-7 cells with IC50 = 1.71 mg/mL. Some CN extracts have the ability to inhibit the proliferation of four different cancer cell lines after a 24 hour treatment. Annexin V assay results showed that acetone extracts of CN induced increments in the percentage of apoptotic cell death. However, flow cytometry results showed that the cancer cell cycle profile was not affected. Similarly, immunoblotting results also indicate that microtubule dynamics in MCF-7 cells were not altered. However, the aqueous extract, prepared to simulate the current ethnomedicinal use of CN leaves in cancer treatment, did not significantly inhibit cancer cell proliferation with an IC50 = 1.71 mg/mL. Conclusions: This study was the first to show that microtubules in cancer cells remain dynamic after treatment with CN extracts, effectively ruling interference of microtubule dynamics as the mode of cell death. AMD extract showed the highest effects of MCF-7 cell proliferation.

Altered mechanical properties of actin fibers due to breast cancer invasion: parameter identification based on micropipette aspiration and multiscale tensegrity modeling.

The biophysical properties of cells change with cancer invasion to fulfill their metastatic behavior. Cell softening induced by cancer is highly associated with alterations in cytoskeleton fibers. Changes in the mechanical properties of cytoskeletal fibers have not been quantified due to technical limitations. In this study, we used the micropipette aspiration technique to calculate and compare the viscoelastic properties of non-invasive and invasive breast cancer cells. We evaluated the mechanical properties of actin fibers and microtubules of two cancerous cell lines by using multiscale tensegrity modeling and an optimization method. Cancer invasion caused altered viscoelastic behavior of cells and the results of modeling showed changes in mechanical properties of major cytoskeleton fibers. The stiffness and viscosity constant of actin fibers in non-invasive cells were 1.28 and 2.27 times higher than those of the invasive cells, respectively. However, changes in mechanical properties of microtubules were minor. Immunofluorescent staining of fibers and their quantified distributions confirmed altered actin distribution among two cell lines, in contrast to microtubule distribution. This study highlights the function of cytoskeletal fibers in cancer progression, which could be of interest in designing therapeutic strategies to target cancer progress. Firstly, the viscoelastic behavior of non-invasive and invasive cells is examined with micropipette aspiration tests. A tensegrity model of cells is developed to mimic the viscoelastic behavior of cells, and tensegrity element stiffness is evaluated in an optimization procedure based on micropipette aspiration tests. Finally, by using immunofluorescent staining and confocal imaging, mechanical properties of actin filaments and microtubules of cancer cells are investigated during the course of metastasis.

Local Delivery of Taxol From FGL-Functionalized Self-Assembling Peptide Nanofiber Scaffold Promotes Recovery After Spinal Cord Injury.

Taxol has been clinically approved as an antitumor drug, and it exerts its antitumor effect through the excessive stabilization of microtubules in cancer cells. Recently, moderate microtubule stabilization by Taxol has been shown to efficiently promote neurite regeneration and functional recovery after spinal cord injury (SCI). However, the potential for the clinical translation of Taxol in treating SCI is limited by its side effects and low ability to cross the blood-spinal cord barrier (BSCB). Self-assembled peptide hydrogels have shown potential as drug carriers for the local delivery of therapeutic agents. We therefore hypothesized that the localized delivery of Taxol by a self-assembled peptide scaffold would promote axonal regeneration by stabilizing microtubules during the treatment of SCI. In the present study, the mechanistic functions of the Taxol-releasing system were clarified in vitro and in vivo using immunofluorescence labeling, histology and neurobehavioral analyses. Based on the findings from the in vitro study, Taxol released from a biological functionalized SAP nanofiber scaffold (FGLmx/Taxol) remained active and promoted neurite extension. In this study, we used a weight-drop contusion model to induce SCI at T9. The local delivery of Taxol from FGLmx/Taxol significantly decreased glial scarring and increased the number of nerve fibers compared with the use of FGLmx and 5% glucose. Furthermore, animals administered FGLmx/Taxol exhibited neurite preservation, smaller cavity dimensions, and decreased inflammation and demyelination. Thus, the local delivery of Taxol from FGLmx/Taxol was effective at promoting recovery after SCI and has potential as a new therapeutic strategy for SCI.

Novel colchicine conjugate with unusual effect on the microtubules of cancer cells

Abstract Colchicine derivative bearing substituted bispidine moiety, namely N-{7-(3,7-Di-(tert-butoxycarbonyl)-1,5-dimethyl-3,7-diazabicyclo[3.3.1]nonan-9-yl)-oxy-7-oxoheptanoyl}-N-deacetylcolchicine, was synthesized and tested for its effect on the net of microtubules (MT) in lung cancer cells A549. The compound induced not only MT depolymerization but stimulated the formation of small tubulin aggregates and long tubulin fibrils localized mainly around nuclei. The assemblies were morphologically different from tubulin clusters induced by structurally related anticancer agent tubuloclustin. The biotests data demonstrate that the depolymerization takes place for both pure tubulin and tubulin in cellulo, while fibrils are formed only in the cells. The research data of structure–activity relationship for several similar colchicine derivatives synthesized in the work give evidence for the proposition that the initial conjugate may interact not only with tubulin and MT in the cells, but also with MT-associated proteins, involved in the process of tubulin polymerization. The ability to affect simultaneously MAP – tubulin interactions opens attractive prospects in the design of novel anticancer agents.

Antitumour effects of Liporaxel (oral paclitaxel) for canine melanoma in a mouse xenograft model.

Paclitaxel, a member of the taxane family, exhibits antitumour effects by targeting the microtubules in cancer cells. Recently, oral paclitaxel has been developed to overcome the side effects of intravenous paclitaxel administration in human patients. The objective of this study was to investigate the antitumour effects of oral paclitaxel in vitro and in vivo. Three weeks after inoculation, oral paclitaxel (25 and 50 mg/kg) or saline was administered every week for three consecutive weeks. To explore the underlying mechanism, tumour angiogenesis was examined by immunohistochemistry with an anti-CD31 antibody. Tumour cell apoptosis was detected by Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling assay, and cell cycle arrest was confirmed by western blot analysis. Oral paclitaxel treatment of canine melanoma cells exerted mediated antiproliferative effects and mediated cell cycle arrest in vitro. In animal experiments, after oral paclitaxel administration, the average tumour size decreased to approximately 30% of that in the control. Histologically, oral paclitaxel showed anti-angiogenic effects and induced the apoptosis in tumour tissues. Oral paclitaxel also downregulated the intratumoural expression of cyclin D1 and inhibited cell proliferation. The study findings support potential application of oral paclitaxel as a novel chemotherapeutic strategy to treat canine melanoma. This is the first study to investigate the potential of oral paclitaxel as a therapeutic drug against canine tumours.

Deregulated ALG-2/HEBP2 axis alters microtubule dynamics and mitotic spindle behavior to stimulate cancer development.

Cancer cells are characterized by genomic instability, resulting in the accumulation of mutations that promote cancer progression. One way that genomic instability can arise is through improper regulation of the microtubule cytoskeleton that impacts the function of the mitotic spindle. In this study, we have identified a critical role for the interaction between apoptosis-linked gene 2 (ALG-2) and heme-binding protein 2 (HEBP2) in the above processes. Our data show that the gene copy numbers and mRNA levels for both ALG-2 and HEBP2 are significantly upregulated in breast and lung cancer. Coexpression of ALG-2 and HEBP2 markedly increases the cytoplasmic pool of ALG-2 and alters the subcellular distribution of HEBP2. Our data further reveal that abnormality in the ALG-2/HEBP2 interaction impairs spindle orientation and positioning during mitosis. In addition, this complex appears to modulate the dynamic properties of microtubules in cancer cells. These finding thus uncover an important function for deregulated ALG-2/HEBP2 axis in cancer development by influencing microtubule dynamics and spindle behavior, providing novel insight into the etiology and pathogenesis of cancer.

Diaphanous-related formin 1 as a target for tumor therapy.

Formins nucleate actin and stabilize microtubules (MTs). Expression of the formin Diaphanous homolog 1 (DIAPH1) is increased in malignant colon carcinoma cells, while expression of DIAPH3 is up-regulated in breast and prostate carcinoma cells. Both DIAPH1 isoforms are required to stabilize interphase MTs of cancer cells, and it has been shown that loss of this function decreases the metastatic potential of these cells. Moreover, depletion of DIAPH3 increases the sensitivity of breast and prostate carcinoma cells to taxanes. In contrast with DIAPH1 + 3, DIAPH2 regulates metaphase MTs of tumor cells by stabilizing binding of kinetochore MTs to chromosomes. Depletion of DIAPH2 impairs chromosome alignment, thus proper chromosome segregation during mitosis. In summary, expression of DIAPH formins in tumor cells is essential for stabilizing interphase or metaphase MTs, respectively. Thus, it would be very interesting to analyze if tumor cells exhibiting low DIAPH expression are more sensitive to taxanes than those with high DIAPH expression.

Abstract 3856: The atomic basis for paclitaxel sensitization following loss of CRMP2 phosphorylation in ovarian cancer cells

Abstract The chemotherapeutic agent paclitaxel increases cancer cell microtubule stability, induces mitotic arrest and cancer cell death and improves survival of cancer patients. However, in ovarian and other cancers, it only elicits a response in less than half of patients who receive it. We have previously shown that enhancing microtubule stability in cells prior to paclitaxel treatment, further increases paclitaxel-induced microtubule stability and cancer cell death (Ahmed et al., Cancer Cell, 2007;12:514 and Ahmed et al., Cancer Research 2011;71:5806). We now report that the microtubule-associated protein CRMP2, and FER kinase are expressed in almost half of high-grade serous ovarian cancers and that inhibiting the phosphorylation of CRMP2 by FER is sufficient for enhancing paclitaxel-induced microtubule stability and cytotoxicity in multiple ovarian cancer cell lines. We are also able propose a detailed mechanism underlying these observations. A combination of biochemistry, super-resolution fluorescence microscopy, total internal reflection fluorescence (TIRF) microscopy and electron microscopy reveals that CRMP2 induces microtubule nucleation, elongation, bundling and stability. Moreover, FER phosphorylates CRMP2 at 6 tyrosine residues, two of which (Tyr479 and Tyr499) are critical for modulating CRMP2 function; this agrees with site-directed mutagenesis in cancer cells which points to Tyr479 as a critical site for association between CRMP2 and microtubules. A comparison of the crystal structures of wild-type CRMP2 and Tyr479Glu/Tyr499Glu phosphomimetic mutants indicate that phosphorylation of these sites induces significant conformational changes that prevent CRMP2 from forming tetramers that are known to be critical for its microtubule bundling activity. This then leads us to propose a molecular model of how CRMP2 associates with microtubules, explaining how targeting CRMP2 phosphorylation can be exploited for enhancing the therapeutic efficacy of paclitaxel. Citation Format: Yiyan Zheng, Ritika Sethi, Frank von Delft, Ahmed Ashour Ahmed. The atomic basis for paclitaxel sensitization following loss of CRMP2 phosphorylation in ovarian cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3856.

Protective effects of fucoidan on the cell death of spleen cells induced by taxol

Taxol is an anti-cancer agent that stabilizes the microtubules of cancer cells, resulting in inhibition of mitosis and thus preventing the proliferation of cancer cells. However, many anti-cancer agents including taxol work on normal cells as well as cancer cells, resulting in side effects such as immunosuppression. A marine algae-derived sulfated polysaccharide, fucoidan, an anti-cancer agent, also showed immunostimulating effects. This study investigated the effects of fucoidan on taxol-treated spleen cells. Spleen cells were treated with taxol in a concentration-dependent manner and in combination with fucoidan. MTT assay and flow cytometry analysis were performed to measure the viability and activity of treated cells. Two assays demonstrated that taxol induced the death of spleen cells. Fucoidan clearly inhibited the cell death induced by taxol. In addition, fucoidan enhanced the production of nitric oxide in spleen cells, which was decreased by taxol. Taken together, taxol can induce the cell death of spleen cells, a major type of immune cells and fucoidan protects spleen cells from taxol-induced cell death. This finding suggests that taxol and fucoidan can be used in combination for lowering the immunosuppressive effects of taxol.

Novel cis-selective and non-epimerisable C3 hydroxy azapodophyllotoxins targeting microtubules in cancer cells

Podophyllotoxin (PT) and its clinically used analogues are known to be powerful antitumour agents. These compounds contain a trans fused strained γ-lactone system, a feature that correlates to the process of epimerisation, whereby the trans γ-lactone system of ring D opens and converts to the more thermodynamically stable cis epimer. Since these cis epimers are known to be either less active or lacking antitumour activity, epimerisation is an undesirable feature from a chemotherapeutic point of view. To circumvent this problem, considerable efforts have been reported, amongst which is the synthesis of azapodophyllotoxins where the stereocentres at C2 and C3 are removed in order to preclude epimerisation. Herein we report the identification of a novel C3 hydroxy, cis-selective γ-lactone configuration of ring C in the azapodophyllotoxin scaffold, through an efficient stereoselective multicomponent reaction (MCR) involving fluorinated and non-fluorinated aldehydes. This configuration releases the highly strained trans γ-lactone system in podophyllotoxin analogues into the more thermodynamically stable cis γ-lactone motif and yet retains significantly potent activity. These compounds were evaluated against the human cancer lines MCF-7 and 22Rv1 in vitro. Fourteen out of the seventeen tested compounds exhibited sub-micromolar activity with IC50 values in the range of 0.11–0.91 μM, which is comparable and in some cases better than the activity profile of etoposide in this assay. Interestingly, we obtained strong evidence from spectroscopic and X-ray data analyses that the previously reported structure of similar analogues is not accurate. Molecular modelling performed using the podophyllotoxin binding site on β tubulin revealed a novel binding mode of these analogues. Furthermore, sub-cellular study of our compounds using immunolabelling and confocal microscopy analyses showed strong microtubule disruptive activity, particularly in dividing cells.

Mitochondrial Dysfunction and Disturbed Coherence: Gate to Cancer

Continuous energy supply, a necessary condition for life, excites a state far from thermodynamic equilibrium, in particular coherent electric polar vibrations depending on water ordering in the cell. Disturbances in oxidative metabolism and coherence are a central issue in cancer development. Oxidative metabolism may be impaired by decreased pyruvate transfer to the mitochondrial matrix, either by parasitic consumption and/or mitochondrial dysfunction. This can in turn lead to disturbance in water molecules’ ordering, diminished power, and coherence of the electromagnetic field. In tumors with the Warburg (reverse Warburg) effect, mitochondrial dysfunction affects cancer cells (fibroblasts associated with cancer cells), and the electromagnetic field generated by microtubules in cancer cells has low power (high power due to transport of energy-rich metabolites from fibroblasts), disturbed coherence, and a shifted frequency spectrum according to changed power. Therapeutic strategies restoring mitochondrial function may trigger apoptosis in treated cells; yet, before this step is performed, induction (inhibition) of pyruvate dehydrogenase kinases (phosphatases) may restore the cancer state. In tumor tissues with the reverse Warburg effect, Caveolin-1 levels should be restored and the transport of energy-rich metabolites interrupted to cancer cells. In both cancer phenotypes, achieving permanently reversed mitochondrial dysfunction with metabolic-modulating drugs may be an effective, specific anti-cancer strategy.

Microtubule C-Terminal Tails Can Change Characteristics of Motor Force Production.

Control of intracellular transport is poorly understood, and functional ramifications of tubulin isoform differences between cell types are mostly unexplored. Motors' force production and detachment kinetics are critical for their group function, but how microtubule (MT) details affect these properties--if at all--is unknown. We investigated these questions using both a vesicular transport human kinesin, kinesin-1, and also a mitotic kinesin likely optimized for group function, kinesin-5, moving along either bovine brain or MCF7(breast cancer) MTs. We found that kinesin-1 functioned similarly on the two sets of MTs--in particular, its mean force production was approximately the same, though due to its previously reported decreased processivity, the mean duration of kinesin-1 force production was slightly decreased on MCF7 MTs. In contrast, kinesin-5's function changed dramatically on MCF7 MTs: its average detachment force was reduced and its force-velocity curve was different. In spite of the reduced detachment force, the force-velocity alteration surprisingly improved high-load group function for kinesin-5 on the cancer-cell MTs, potentially contributing to functions such as spindle-mediated chromosome separation. Significant differences were previously reported for C-terminal tubulin tails in MCF7 versus bovine brain tubulin. Consistent with this difference being functionally important, elimination of the tails made transport along the two sets of MTs similar.