scholarly journals Voltage-Gated K+ Channels Promote BT-474 Breast Cancer Cell Migration

2018 ◽  
Vol 4 (Supplement 2) ◽  
pp. 192s-192s
Author(s):  
L.W.C. Chow ◽  
K.S. Cheng ◽  
K.L. Wong ◽  
Y.M. Leung
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Cancer Metastasis ◽  
Delayed Rectifier ◽  
Bt474 Cell ◽  
Membrane Hyperpolarization ◽  
Voltage Gated ◽  
Kv Channel ◽  
Kv Channels ◽  
Migratory Cells

Objective: A variety of ion channels have been implicated in breast cancer proliferation and metastasis. Voltage-gated K+ (Kv) channels not only cause repolarization in excitable cells, but are also involved in multiple cellular functions in nonexcitable cells. In this study we investigated the role of Kv channels in migration of BT474 breast cancer cells. Methods: Transwell technique was used to separate migratory cells from nonmigratory ones and these 2 groups of cells were subject to electrophysiological examinations and microfluorimetric measurements for cytosolic Ca2+. Cell migration was examined in the absence or presence of Kv channel blockers. Results: When compared with nonmigratory cells, migratory cells had much higher Kv current densities, but rather unexpectedly, more depolarized membrane potential and reduced Ca2+ influx. PCR analysis revealed the presence of Kv1.4, Kv1.5, Kv1.6, Kv2.1 and Kv3.1 channels. Cell migration was markedly inhibited by tetraethylammonium, a delayed rectifier Kv channel blocker, but not by 4-aminopyridine, an A-type Kv blocker. Conclusion: Taken together, our results show that increased Kv channel expression played a role in BT474 cell migration, and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer metastasis. The mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Ca2+ influx.

Activation of K+ channels and increased migration of differentiated intestinal epithelial cells after wounding

2002 ◽  
Vol 282 (4) ◽  
pp. C885-C898 ◽  
Author(s):  
Jaladanki N. Rao ◽  
Oleksandr Platoshyn ◽  
Li Li ◽  
Xin Guo ◽  
Vera A. Golovina ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Fiber Formation ◽  
Intestinal Epithelial ◽  
Membrane Hyperpolarization ◽  
Kv Channel ◽  
Kv Channels ◽  
Channel Expression

Early mucosal restitution occurs by epithelial cell migration to reseal superficial wounds after injury. Differentiated intestinal epithelial cells induced by forced expression of the Cdx2 gene migrate over the wounded edge much faster than undifferentiated parental cells in an in vitro model. This study determined whether these differentiated intestinal epithelial cells exhibit increased migration by altering voltage-gated K+ (Kv) channel expression and cytosolic free Ca2+ concentration ([Ca2+]cyt). Stable Cdx2-transfected IEC-6 cells (IEC-Cdx2L1) with highly differentiated phenotype expressed higher basal levels of Kv1.1 and Kv1.5 mRNAs and proteins than parental IEC-6 cells. Neither IEC-Cdx2L1 cells nor parental IEC-6 cells expressed voltage-dependent Ca2+ channels. The increased expression of Kv channels in differentiated IEC-Cdx2L1 cells was associated with an increase in whole cell K+ currents, membrane hyperpolarization, and a rise in [Ca2+]cyt. The migration rates in differentiated IEC-Cdx2L1 cells were about four times those of parental IEC-6 cells. Inhibition of Kv channel expression by polyamine depletion decreased [Ca2+]cyt, reduced myosin stress fibers, and inhibited cell migration. Elevation of [Ca2+]cyt by ionomycin promoted myosin II stress fiber formation and increased cell migration. These results suggest that increased migration of differentiated intestinal epithelial cells is mediated, at least partially, by increasing Kv channel activity and Ca2+ influx during restitution.

scholarly journals E2F1 Drives Breast Cancer Metastasis by Regulating the Target Gene FGF13 and Altering Cell Migration

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Daniel P. Hollern ◽  
Matthew R. Swiatnicki ◽  
Jonathan P. Rennhack ◽  
Sean A. Misek ◽  
Brooke C. Matson ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Target Gene ◽  
Cancer Metastasis ◽  
Breast Cancer Metastasis

scholarly journals Extracellular Vesicle-Mediated Purinergic Signaling Contributes to Host Microenvironment Plasticity and Metastasis in Triple Negative Breast Cancer

2020 ◽  
Author(s):  
Suzann Duan ◽  
Senny Nordmeier ◽  
Aidan E. Byrnes ◽  
Iain L. O. Buxton
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Endothelial Cell ◽  
Triple Negative Breast Cancer ◽  
Cancer Metastasis ◽  
Triple Negative ◽  
Purinergic Signaling ◽  
Endothelial Cell Migration ◽  
Metastatic Niche ◽  
Niche Formation

AbstractMetastasis accounts for over 90% of cancer-related deaths. The mechanisms guiding this process remain unclear. Secreted nucleoside diphosphate kinase A and B (NDPK) support breast cancer metastasis. Proteomic evidence confirms their presence in breast cancer-derived extracellular vesicles (EVs). We investigated the role of EV-associated NDPK in modulating the host microenvironment in favor of pre-metastatic niche formation. We measured NDPK expression and activity in EVs isolated from triple-negative breast cancer (MDA-MB-231) and non-tumorigenic mammary epithelial (HME1) cells using flow cytometry, western blot, and ATP assay. We evaluated the effects of EV-associated NDPK on endothelial cell migration, vascular remodeling, and metastasis. We further assessed MDA-MB-231 EV induced-proteomic changes in support of pre-metastatic lung niche formation. NDPK-B expression and phosphotransferase activity were enriched in MDA-MB-231 EVs that promote vascular endothelial cell migration and disrupt monolayer integrity. MDA-MB-231 EV-treated mice demonstrate pulmonary vascular leakage and enhanced experimental lung metastasis, whereas treatment with an NDPK inhibitor or a P2Y1 purinoreceptor antagonist blunts these effects. We identified perturbations to the purinergic signaling pathway in experimental lungs, lending evidence to support a role for EV-associated NDPK-B in lung pre-metastatic niche formation and metastatic outgrowth.

scholarly journals Uncovering the signaling landscape controlling breast cancer cell migration identifies splicing factor PRPF4B as a metastasis driver

2018 ◽  
Author(s):  
Michiel Fokkelman ◽  
Esmee Koedoot ◽  
Vasiliki-Maria Rogkoti ◽  
Sylvia E. Le Dévédec ◽  
Iris van de Sandt ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Cancer Metastasis ◽  
Breast Cancer Cell Lines ◽  
Cancer Cell Migration ◽  
Metastasis Formation ◽  
Breast Cancer Cell Migration ◽  
Basal Breast Cancer

AbstractMetastasis is the major cause of death in cancer patients and migration of cancer cells from the primary tumor to distant sites is the prerequisite of metastasis formation. Here we applied an imaging-based RNAi phenotypic cell migration screen using two highly migratory basal breast cancer cell lines (Hs578T and MDA-MB-231) to provide a repository for signaling determinants that functionally drive cancer cell migration. We screened ~4,200 individual target genes covering most cell signaling components and discovered 133 and 113 migratory modulators of Hs578T and MDA-MB-231, respectively, of which 43 genes were common denominators of cell migration. Interaction networks of candidate migratory modulators were in common with networks of different clinical breast cancer prognostic and metastasis classifiers. The splicing factors PRPF4B and BUD31 and the transcription factor BPTF were amplified in human primary breast tumors and the expression was associated with metastasis-free survival. Depletion of PRPF4B, BUD31 and BPTF caused primarily down-regulation of genes involved in focal adhesion and ECM-interaction pathways. PRPF4B was essential for triple negative breast cancer cell migration and critical for breast cancer metastasis formation in vivo, making PRPF4B a candidate for further drug development. Our systematic phenotypic screen provides an important repository of candidate metastasis drug targets.

scholarly journals Role of K+ channel expression in polyamine-dependent intestinal epithelial cell migration

2000 ◽  
Vol 278 (2) ◽  
pp. C303-C314 ◽  
Author(s):  
Jian-Ying Wang ◽  
Jian Wang ◽  
Vera A. Golovina ◽  
Li Li ◽  
Oleksandr Platoshyn ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cell ◽  
Driving Force ◽  
Intestinal Epithelial Cell ◽  
Delayed Rectifier ◽  
Intestinal Epithelial ◽  
Voltage Gated ◽  
Epithelial Cell Migration ◽  
Channel Expression ◽  
Exogenous Spermidine

Polyamines are essential for cell migration during early mucosal restitution after wounding in the gastrointestinal tract. Activity of voltage-gated K+ channels (Kv) controls membrane potential ( E m) that regulates cytoplasmic free Ca2+ concentration ([Ca2+]cyt) by governing the driving force for Ca2+ influx. This study determined whether polyamines are required for the stimulation of cell migration by altering K+ channel gene expression, E m, and [Ca2+]cyt in intestinal epithelial cells (IEC-6). The specific inhibitor of polyamine synthesis, α-difluoromethylornithine (DFMO, 5 mM), depleted cellular polyamines (putrescine, spermidine, and spermine), selectively inhibited Kv1.1 channel (a delayed-rectifier Kv channel) expression, and resulted in membrane depolarization. Because IEC-6 cells did not express voltage-gated Ca2+ channels, the depolarized E m in DFMO-treated cells decreased [Ca2+]cyt as a result of reduced driving force for Ca2+ influx through capacitative Ca2+ entry. Migration was reduced by 80% in the polyamine-deficient cells. Exogenous spermidine not only reversed the effects of DFMO on Kv1.1 channel expression, E m, and [Ca2+]cyt but also restored cell migration to normal. Removal of extracellular Ca2+ or blockade of Kv channels (by 4-aminopyridine, 1–5 mM) significantly inhibited normal cell migration and prevented the restoration of cell migration by exogenous spermidine in polyamine-deficient cells. These results suggest that polyamine-dependent intestinal epithelial cell migration may be due partially to an increase of Kv1.1 channel expression. The subsequent membrane hyperpolarization raises [Ca2+]cyt by increasing the driving force (the electrochemical gradient) for Ca2+ influx and thus stimulates cell migration.

Inhibition of voltage-gated K+ channels in dendritic cells by rapamycin

2010 ◽  
Vol 299 (6) ◽  
pp. C1379-C1385 ◽  
Author(s):  
Leonid Tyan ◽  
Mentor Sopjani ◽  
Miribane Dërmaku-Sopjani ◽  
Evi Schmid ◽  
Wenting Yang ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Xenopus Oocytes ◽  
Statistical Significance ◽  
Immunosuppressive Drug ◽  
Channel Activity ◽  
Voltage Gated ◽  
Kv Channel ◽  
Kv Channels ◽  
Channel Inactivation ◽  
Kv1.3 Channel

Rapamycin, an inhibitor of the serine/threonine kinase mammalian target of rapamycin (mTOR), is a widely used immunosuppressive drug. Rapamycin affects the function of dendritic cells (DCs), antigen-presenting cells participating in the initiation of primary immune responses and the establishment of immunological memory. Voltage-gated K+ (Kv) channels are expressed in and impact on the function of DCs. The present study explored whether rapamycin influences Kv channels in DCs. To this end, DCs were isolated from murine bone marrow and ion channel activity was determined by whole cell patch clamp. To more directly analyze an effect of mTOR on Kv channel activity, Kv1.3 and Kv1.5 were expressed in Xenopus oocytes with or without the additional expression of mTOR and voltage-gated currents were determined by dual-electrode voltage clamp. As a result, preincubation with rapamycin (0–50 nM) led to a gradual decline of Kv currents in DCs, reaching statistical significance within 6 h and 50 nM of rapamycin. Rapamycin accelerated Kv channel inactivation. Coexpression of mTOR upregulated Kv1.3 and Kv1.5 currents in Xenopus oocytes. Furthermore, mTOR accelerated Kv1.3 channel activation and slowed down Kv1.3 channel inactivation. In conclusion, mTOR stimulates Kv channels, an effect contributing to the immunomodulating properties of rapamycin in DCs.

scholarly journals Tyrosine Phosphatases ε and α Perform Specific and Overlapping Functions in Regulation of Voltage-gated Potassium Channels in Schwann Cells

2006 ◽  
Vol 17 (10) ◽  
pp. 4330-4342 ◽  
Author(s):  
Zohar Tiran ◽  
Asher Peretz ◽  
Tal Sines ◽  
Vera Shinder ◽  
Jan Sap ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cells ◽  
Tyrosine Phosphatases ◽  
Open Probability ◽  
Voltage Gated ◽  
Kv Channel ◽  
Kv Channels ◽  
Or Organization ◽  
Unexpected Difference

Tyrosine phosphatases (PTPs) ε and α are closely related and share several molecular functions, such as regulation of Src family kinases and voltage-gated potassium (Kv) channels. Functional interrelationships between PTPε and PTPα and the mechanisms by which they regulate K+ channels and Src were analyzed in vivo in mice lacking either or both PTPs. Lack of either PTP increases Kv channel activity and phosphorylation in Schwann cells, indicating these PTPs inhibit Kv current amplitude in vivo. Open probability and unitary conductance of Kv channels are unchanged, suggesting an effect on channel number or organization. PTPα inhibits Kv channels more strongly than PTPε; this correlates with constitutive association of PTPα with Kv2.1, driven by membranal localization of PTPα. PTPα, but not PTPε, activates Src in sciatic nerve extracts, suggesting Src deregulation is not responsible exclusively for the observed phenotypes and highlighting an unexpected difference between both PTPs. Developmentally, sciatic nerve myelination is reduced transiently in mice lacking either PTP and more so in mice lacking both PTPs, suggesting both PTPs support myelination but are not fully redundant. We conclude that PTPε and PTPα differ significantly in their regulation of Kv channels and Src in the system examined and that similarity between PTPs does not necessarily result in full functional redundancy in vivo.

scholarly journals The Amyloid Precursor Protein C99 Fragment Modulates Voltage-Gated Potassium Channels.

2021 ◽  
Vol 55 (S3) ◽  
pp. 157-170
Keyword(s):  
Amyloid Precursor Protein ◽  
Protein Interactions ◽  
Precursor Protein ◽  
Xenopus Laevis Oocytes ◽  
Cellular Functions ◽  
Voltage Gated ◽  
Adult Rat ◽  
Kv Channel ◽  
Kv Channels

BACKGROUND/AIMS: The Amyloid Precursor Protein (APP) is involved in the regulation of multiple cellular functions via protein-protein interactions and has been most studied with respect to Alzheimer's disease (AD). Abnormal processing of the single transmembrane-spanning C99 fragment of APP contributes to the formation of amyloid plaques, which are causally related to AD. Pathological C99 accumulation is thought to associate with early cognitive defects in AD. Here, unexpectedly, sequence analysis revealed that C99 exhibits 24% sequence identity with the KCNE1 voltage-gated potassium (Kv) channel β subunit, comparable to the identity between KCNE1 and KCNE2-5 (21-30%). This suggested the possibility of C99 regulating Kv channels. METHODS: We quantified the effects of C99 on Kv channel function, using electrophysiological analysis of subunits expressed in Xenopus laevis oocytes, biochemical and immunofluorescence techniques. RESULTS: C99 isoform-selectively inhibited (by 30-80%) activity of a range of Kv channels. Among the KCNQ (Kv7) family, C99 isoform-selectively inhibited, shifted the voltage dependence and/or slowed activation of KCNQ2, KCNQ3, KCNQ2/3 and KCNQ5, with no effects on KCNQ1, KCNQ1-KCNE1 or KCNQ4. C99/APP co-localized with KCNQ2 and KCNQ3 in adult rat sciatic nerve nodes of Ranvier. Both C99 and full-length APP co-immunoprecipitated with KCNQ2 in vitro, yet unlike C99, APP only weakly affected KCNQ2/3 activity. Finally, C99 altered the effects on KCNQ2/3 function of inhibitors tetraethylammounium and XE991, but not openers retigabine and ICA27243.

Single-cell RNA-sequencing of migratory breast cancer cells: discovering genes associated with cancer metastasis

The Analyst ◽  
2019 ◽  
Vol 144 (24) ◽  
pp. 7296-7309 ◽  
Author(s):  
Yu-Chih Chen ◽  
Saswat Sahoo ◽  
Riley Brien ◽  
Seungwon Jung ◽  
Brock Humphries ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Single Cell ◽  
Cancer Cells ◽  
Rna Sequencing ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Tumor Formation ◽  
Single Cell Rna Sequencing ◽  
Migratory Cells

We enriched migratory breast cancer cells with enhanced tumor formation and metastasis capability using microfluidics and performed single-cell RNA-sequencing to identify unique EMT and CSC signature of migratory cells.

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