scholarly journals Actomyosin, vimentin and LINC complex pull on osteosarcoma nuclei to deform on micropillar topography

2019 ◽  
Author(s):  
Nayana Tusamda Wakhloo ◽  
Sebastian Anders ◽  
Florent Badique ◽  
Melanie Eichhorn ◽  
Isabelle Brigaud ◽  
...  
Keyword(s):  
Cancer Metastasis ◽  
Cell Model ◽  
Cell Deformation ◽  
Nuclear Deformation ◽  
Biological Processes ◽  
Linc Complex ◽  
Actomyosin Contractility ◽  
Pulling Forces ◽  
Underlying Mechanisms

ABSTRACTCell deformation occurs in many critical biological processes, including cell extravasation during immune response and cancer metastasis. These cells deform the nucleus, its largest and stiffest organelle, while passing through narrow constrictions in vivo and the underlying mechanisms still remain elusive. It is unclear which biochemical actors are responsible and whether the nucleus is pushed or pulled (or both) during deformation. Herein we use an easily-tunable poly-L-lactic acid micropillar topography, mimicking in vivo constrictions to determine the mechanisms responsible for nucleus deformation. Using biochemical tools, we determine that actomyosin contractility, vimentin and nucleo-cytoskeletal connections play essential roles in nuclear deformation, but not A-type lamins. We chemically tune the adhesiveness of the micropillars to show that pulling forces are predominantly responsible for the deformation of the nucleus. We confirm these results using an in silico cell model and propose a comprehensive mechanism for cellular and nuclear deformation during confinement. These results indicate that microstructured biomaterials are extremely versatile tools to understand how forces are exerted in biological systems and can be useful to dissect and mimic complex in vivo behaviour.

scholarly journals SUN-MKL1 crosstalk regulates nuclear deformation and fast motility of breast carcinoma cells in fibrillar ECM micro-environment

2020 ◽  
Author(s):  
Ved P Sharma ◽  
James Williams ◽  
Edison Leung ◽  
Joe Sanders ◽  
Robert Eddy ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Cell Motility ◽  
Tumor Cells ◽  
Carcinoma Cell ◽  
Nuclear Deformation ◽  
Linc Complex ◽  
Actomyosin Contractility ◽  
Tumor Cell Motility ◽  
Single Tumor

ABSTRACTAligned collagen fibers provide topography for the rapid migration of single tumor cells (streaming migration) to invade the surrounding stroma, move within tumor nests towards blood vessels to intravasate and form distant metastases. Mechanisms of tumor cell motility have been studied extensively in the 2D context, but the mechanistic understanding of rapid single tumor cell motility in the in vivo context is still lacking. Here, we show that streaming tumor cells in vivo use collagen fibers with diameters below 3 μm. Employing 1D migration assays with matching in vivo fiber dimensions, we found a dependence of tumor cell motility on 1D substrate width, with cells moving the fastest and the most persistently on the narrowest 1D fibers (700 nm – 2.5 μm). Interestingly, we also observed nuclear deformation in the absence of restricting extracellular matrix pores during high speed carcinoma cell migration in 1D, similar to the nuclear deformation observed in tumor cells in vivo. Further, we found that actomyosin machinery is aligned along the 1D axis and actomyosin contractility synchronously regulates cell motility and nuclear deformation. To further investigate the link between cell speed and nuclear deformation, we focused on the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex proteins and SRF-MKL1 signaling, key regulators of mechanotransduction, actomyosin contractility and actin-based cell motility. Analysis of The Cancer Genome Atlas dataset showed a dramatic decrease in the LINC complex proteins SUN1 and SUN2 in primary tumor compared to the normal tissue. Disruption of LINC complex by SUN1+2 KD led to multi-lobular elongated nuclei, increased tumor cell motility and concomitant increase in F-actin, without affecting Lamin proteins. Mechanistically, we found that MKL1, an effector of changes in cellular G-actin to F-actin ratio, is required for increased 1D motility seen in SUN1+2 KD cells. Thus, we demonstrate a previously unrecognized crosstalk between SUN proteins and MKL1 transcription factor in modulating nuclear shape and carcinoma cell motility in an in vivo relevant 1D microenvironment.

scholarly journals SUN-MKL1 Crosstalk Regulates Nuclear Deformation and Fast Motility of Breast Carcinoma Cells in Fibrillar ECM Microenvironment

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1549
Author(s):  
Ved P. Sharma ◽  
James Williams ◽  
Edison Leung ◽  
Joe Sanders ◽  
Robert Eddy ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Cell Motility ◽  
Tumor Cells ◽  
Carcinoma Cell ◽  
Nuclear Deformation ◽  
Linc Complex ◽  
Actomyosin Contractility ◽  
Tumor Cell Motility ◽  
Single Tumor

Aligned collagen fibers provide topography for the rapid migration of single tumor cells (streaming migration) to invade the surrounding stroma, move within tumor nests towards blood vessels to intravasate and form distant metastases. Mechanisms of tumor cell motility have been studied extensively in the 2D context, but the mechanistic understanding of rapid single tumor cell motility in the in vivo context is still lacking. Here, we show that streaming tumor cells in vivo use collagen fibers with diameters below 3 µm. Employing 1D migration assays with matching in vivo fiber dimensions, we found a dependence of tumor cell motility on 1D substrate width, with cells moving the fastest and the most persistently on the narrowest 1D fibers (700 nm–2.5 µm). Interestingly, we also observed nuclear deformation in the absence of restricting extracellular matrix pores during high speed carcinoma cell migration in 1D, similar to the nuclear deformation observed in tumor cells in vivo. Further, we found that actomyosin machinery is aligned along the 1D axis and actomyosin contractility synchronously regulates cell motility and nuclear deformation. To further investigate the link between cell speed and nuclear deformation, we focused on the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex proteins and SRF-MKL1 signaling, key regulators of mechanotransduction, actomyosin contractility and actin-based cell motility. Analysis of The Cancer Genome Atlas dataset showed a dramatic decrease in the LINC complex proteins SUN1 and SUN2 in primary tumor compared to the normal tissue. Disruption of LINC complex by SUN1 + 2 KD led to multi-lobular elongated nuclei, increased tumor cell motility and concomitant increase in F-actin, without affecting Lamin proteins. Mechanistically, we found that MKL1, an effector of changes in cellular G-actin to F-actin ratio, is required for increased 1D motility seen in SUN1 + 2 KD cells. Thus, we demonstrate a previously unrecognized crosstalk between SUN proteins and MKL1 transcription factor in modulating nuclear shape and carcinoma cell motility in an in vivo relevant 1D microenvironment.

scholarly journals The Beneficial Effects of Morusin, an Isoprene Flavonoid Isolated from the Root Bark of Morus

2020 ◽  
Vol 21 (18) ◽  
pp. 6541
Author(s):  
Dong Wook Choi ◽  
Sang Woo Cho ◽  
Seok-Geun Lee ◽  
Cheol Yong Choi
Keyword(s):  
Inflammatory Diseases ◽  
Root Bark ◽  
Biological Processes ◽  
Functional Roles ◽  
Beneficial Effects ◽  
Biochemical Identification ◽  
Underlying Mechanisms ◽  
Clinical Potential

The root bark of Morus has long been appreciated as an antiphlogistic, diuretic and expectorant drug in Chinese herbal medicine, albeit with barely known targets and mechanisms of action. In the 1970s, the development of analytic chemistry allowed for the discovery of morusin as one of 7 different isoprene flavonoid derivatives in the root bark of Morus. However, the remarkable antioxidant capacity of morusin with the unexpected potential for health benefits over the other flavonoid derivatives has recently sparked scientific interest in the biochemical identification of target proteins and signaling pathways and further clinical relevance. In this review, we discuss recent advances in the understanding of the functional roles of morusin in multiple biological processes such as inflammation, apoptosis, metabolism and autophagy. We also highlight recent in vivo and in vitro evidence on the clinical potential of morusin treatment for multiple human pathologies including inflammatory diseases, neurological disorders, diabetes, cancer and the underlying mechanisms.

scholarly journals Confinement hinders motility by inducing RhoA-mediated nuclear influx, volume expansion, and blebbing

2019 ◽  
Vol 218 (12) ◽  
pp. 4093-4111 ◽  
Author(s):  
Panagiotis Mistriotis ◽  
Emily O. Wisniewski ◽  
Kaustav Bera ◽  
Jeremy Keys ◽  
Yizeng Li ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Cell Motility ◽  
Volume Expansion ◽  
Myosin Ii ◽  
Nuclear Volume ◽  
Linc Complex ◽  
Actomyosin Contractility ◽  
Dependent Pathway ◽  
Passive Influx

Cells migrate in vivo through complex confining microenvironments, which induce significant nuclear deformation that may lead to nuclear blebbing and nuclear envelope rupture. While actomyosin contractility has been implicated in regulating nuclear envelope integrity, the exact mechanism remains unknown. Here, we argue that confinement-induced activation of RhoA/myosin-II contractility, coupled with LINC complex-dependent nuclear anchoring at the cell posterior, locally increases cytoplasmic pressure and promotes passive influx of cytoplasmic constituents into the nucleus without altering nuclear efflux. Elevated nuclear influx is accompanied by nuclear volume expansion, blebbing, and rupture, ultimately resulting in reduced cell motility. Moreover, inhibition of nuclear efflux is sufficient to increase nuclear volume and blebbing on two-dimensional surfaces, and acts synergistically with RhoA/myosin-II contractility to further augment blebbing in confinement. Cumulatively, confinement regulates nuclear size, nuclear integrity, and cell motility by perturbing nuclear flux homeostasis via a RhoA-dependent pathway.

scholarly journals Exosome-Derived ADAM17 Promotes Liver Metastasis in Colorectal Cancer

2021 ◽  
Vol 12 ◽  
Author(s):  
Jinbing Sun ◽  
Zhihua Lu ◽  
Wei Fu ◽  
Kuangyi Lu ◽  
Xiuwen Gu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Metastatic Colorectal Cancer ◽  
Cancer Cells ◽  
Cancer Metastasis ◽  
Metastatic Niche ◽  
Colorectal Cancer Cells ◽  
Niche Formation ◽  
Underlying Mechanisms

Exosomes derived from cancer cells are deemed important drivers of pre-metastatic niche formation at distant organs, but the underlying mechanisms of their effects remain largely unknow. Although the role of ADAM17 in cancer cells has been well studied, the secreted ADAM17 effects transported via exosomes are less understood. Herein, we show that the level of exosome-derived ADAM17 is elevated in the serum of patients with metastatic colorectal cancer as well as in metastatic colorectal cancer cells. Furthermore, exosomal ADAM17 was shown to promote the migratory ability of colorectal cancer cells by cleaving the E-cadherin junction. Moreover, exosomal ADAM17 overexpression as well as RNA interference results highlighted its function as a tumor metastasis-promoting factor in colorectal cancer in vitro and in vivo. Taken together, our current work suggests that exosomal ADAM17 is involved in pre-metastatic niche formation and may be utilized as a blood-based biomarker of colorectal cancer metastasis.

scholarly journals Long Non-Coding RNA CRYBG3 Promotes Lung Cancer Metastasis via Activating the eEF1A1/MDM2/MTBP Axis

2021 ◽  
Vol 22 (6) ◽  
pp. 3211
Author(s):  
Anqing Wu ◽  
Jiaxin Tang ◽  
Ziyang Guo ◽  
Yingchu Dai ◽  
Jing Nie ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Metastasis ◽  
Major Barrier ◽  
Lung Cancer Metastasis ◽  
Non Coding Rna ◽  
Metastatic Lung ◽  
Associated Proteins ◽  
Underlying Mechanisms ◽  
Patient Prognosis

The occurrence of distant tumor metastases is a major barrier in non-small cell lung cancer (NSCLC) therapy, and seriously affects clinical treatment and patient prognosis. Recently, long non-coding RNAs (lncRNAs) have been demonstrated to be crucial regulators of metastasis in lung cancer. The aim of this study was to reveal the underlying mechanisms of a novel lncRNA LNC CRYBG3 in regulating NSCLC metastasis. Experimental results showed that LNC CRYBG3 was upregulated in NSCLC cells compared with normal tissue cells, and its level was involved in these cells’ metastatic ability. Exogenously overexpressed LNC CRYBG3 increased the metastatic ability and the protein expression level of the metastasis-associated proteins Snail and Vimentin in low metastatic lung cancer HCC827 cell line. In addition, LNC CRYBG3 contributed to HCC827 cell metastasis in vivo. Mechanistically, LNC CRYBG3 could directly combine with eEF1A1 and promote it to move into the nucleus to enhance the transcription of MDM2. Overexpressed MDM2 combined with MDM2 binding protein (MTBP) to reduce the binding of MTBP with ACTN4 and consequently increased cell migration mediated by ACTN4. In conclusion, the LNC CRYBG3/eEF1A1/MDM2/MTBP axis is a novel signaling pathway regulating tumor metastasis and may be a potential therapeutic target for NSCLC treatment.

scholarly journals How the spleen reshapes and retains young and old red blood cells: A computational investigation

2021 ◽  
Vol 17 (11) ◽  
pp. e1009516
Author(s):  
He Li ◽  
Zixiang Leonardo Liu ◽  
Lu Lu ◽  
Pierre Buffet ◽  
George Em Karniadakis
Keyword(s):  
Life Cycle ◽  
Computational Study ◽  
Lymphoid Organ ◽  
Biological Processes ◽  
Immune Functions ◽  
Computational Investigation ◽  
Underlying Mechanisms

The spleen, the largest secondary lymphoid organ in humans, not only fulfils a broad range of immune functions, but also plays an important role in red blood cell’s (RBC) life cycle. Although much progress has been made to elucidate the critical biological processes involved in the maturation of young RBCs (reticulocytes) as well as removal of senescent RBCs in the spleen, the underlying mechanisms driving these processes are still obscure. Herein, we perform a computational study to simulate the passage of RBCs through interendothelial slits (IES) in the spleen at different stages of their lifespan and investigate the role of the spleen in facilitating the maturation of reticulocytes and in clearing the senescent RBCs. Our simulations reveal that at the beginning of the RBC life cycle, intracellular non-deformable particles in reticulocytes can be biomechanically expelled from the cell upon passage through IES, an insightful explanation of why this peculiar “pitting” process is spleen-specific. Our results also show that immature RBCs shed surface area by releasing vesicles after crossing IES and progressively acquire the biconcave shape of mature RBCs. These findings likely explain why RBCs from splenectomized patients are significantly larger than those from nonsplenectomized subjects. Finally, we show that at the end of their life span, senescent RBCs are not only retained by IES due to reduced deformability but also become susceptible to mechanical lysis under shear stress. This finding supports the recent hypothesis that transformation into a hemolyzed ghost is a prerequisite for phagocytosis of senescent RBCs. Altogether, our computational investigation illustrates critical biological processes in the spleen that cannot be observed in vivo or in vitro and offer insights into the role of the spleen in the RBC physiology.

scholarly journals Dynein pulling forces counteract lamin-mediated nuclear stability during nuclear envelope repair

2018 ◽  
Vol 29 (7) ◽  
pp. 852-868 ◽  
Author(s):  
Lauren Penfield ◽  
Brian Wysolmerski ◽  
Michael Mauro ◽  
Reza Farhadifar ◽  
Michael A. Martinez ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Lamina ◽  
C Elegans ◽  
Culture Cells ◽  
Mechanistic Analysis ◽  
Nuclear Stability ◽  
Pulling Forces ◽  
Underlying Mechanisms ◽  
Work Done

Recent work done exclusively in tissue culture cells revealed that the nuclear envelope (NE) ruptures and repairs in interphase. The duration of NE ruptures depends on lamins; however, the underlying mechanisms and relevance to in vivo events are not known. Here, we use the Caenorhabditis elegans zygote to analyze lamin’s role in NE rupture and repair in vivo. Transient NE ruptures and subsequent NE collapse are induced by weaknesses in the nuclear lamina caused by expression of an engineered hypomorphic C. elegans lamin allele. Dynein-generated forces that position nuclei enhance the severity of transient NE ruptures and cause NE collapse. Reduction of dynein forces allows the weakened lamin network to restrict nucleo–cytoplasmic mixing and support stable NE recovery. Surprisingly, the high incidence of transient NE ruptures does not contribute to embryonic lethality, which is instead correlated with stochastic chromosome scattering resulting from premature NE collapse, suggesting that C. elegans tolerates transient losses of NE compartmentalization during early embryogenesis. In sum, we demonstrate that lamin counteracts dynein forces to promote stable NE repair and prevent catastrophic NE collapse, and thus provide the first mechanistic analysis of NE rupture and repair in an organismal context.

scholarly journals Dynein pulling forces on ruptured nuclei counteract lamin-mediated nuclear envelope repair mechanisms in vivo

2017 ◽  
Author(s):  
Lauren Penfield ◽  
Brian Wysolmerski ◽  
Reza Farhadifar ◽  
Michael Martinez ◽  
Ronald Biggs ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Permeability Barrier ◽  
C Elegans ◽  
Culture Cells ◽  
Pulling Forces ◽  
Repair Mechanisms ◽  
Underlying Mechanisms ◽  
Transient Mixing ◽  
Work Done

AbstractRecent work done exclusively in tissue culture cells revealed that the nuclear envelope (NE) undergoes ruptures leading to transient mixing of nuclear and cytoplasmic components. The duration of transient NE ruptures depends on lamins, however the underlying mechanisms and the relevance to in vivo events is not known. Here, we use C. elegans embryos to show that dynein forces that position nuclei increase the severity of lamin-induced NE ruptures in vivo. In the absence of dynein forces, lamin prevents nuclear-cytoplasmic mixing caused by NE ruptures. By monitoring the dynamics of NE rupture events, we demonstrate that lamin is required for a distinct phase in NE recovery that restricts nucleocytoplasmic mixing prior to the full restoration of NE rupture sites. We show that laser-induced puncture of the NE recapitulates phenotypes associated with NE recovery in wild type cells. Surprisingly, we find that embryonic lethality does not correlate with the incidence of NE rupture events suggesting that embryos survive transient losses of NE compartmentalization during early embryogenesis. In addition to presenting the first mechanistic analysis of transient NE ruptures in vivo, this work demonstrates that lamin controls the duration of NE ruptures by opposing dynein forces on ruptured nuclei to allow reestablishment of the NE permeability barrier and subsequent restoration of NE rupture sites.

scholarly journals Dietary delphinidin inhibits human colorectal cancer metastasis associating with upregulation of miR-204-3p and suppression of the integrin/FAK axis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chi-Chou Huang ◽  
Chia-Hung Hung ◽  
Tung-Wei Hung ◽  
Yi-Chieh Lin ◽  
Chau-Jong Wang ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Migration And Invasion ◽  
Colorectal Cancer Metastasis ◽  
Β3 Integrin ◽  
Underlying Mechanisms ◽  
Sw620 Cells

AbstractDelphinidin is a flavonoid belonging to dietary anthocyanidin family that has been reported to possess diverse anti-tumoral activities. However, the effects of delphinidin on colorectal cancer (CRC) cells and the underlying mechanisms are not fully understood. Thus, we aimed to investigate the anti-cancer activity of delphinidin in CRC cells and the underlying molecular mechanisms. The effects of delphinidin on the viability, metastatic characteristics, signaling, and microRNA (miR) profile of human CRC cell lines used were analyzed. In vivo metastasis was also evaluated using xenograft animal models. Our findings showed that delphinidin (<100 μM) inhibited the colony formation of DLD-1, SW480, and SW620 cells, but non-significantly affected cell viability. Delphinidin also suppressed the migratory ability and invasiveness of the tested CRC cell lines, downregulated integrin αV/β3 expression, inhibited focal adhesion kinase (FAK)/Src/paxillin signaling, and interfered with cytoskeletal construction. Analysis of the miR expression profile revealed a number of miRs, particularly miR-204-3p, that were significantly upregulated and downregulated by delphinidin. Abolishing the expression of one upregulated miR, miR-204-3p, with an antagomir restored delphinidin-mediated inhibition of cell migration and invasiveness in DLD-1 cells as well as the αV/β3-integrin/FAK/Src axis. Delphinidin also inhibited the lung metastasis of DLD-1 cells in the xenograft animal model. Collectively, these results indicate that the migration and invasion of CRC cells are inhibited by delphinidin, and the mechanism may involve the upregulation of miR-204-3p and consequent suppression of the αV/β3-integrin/FAK axis. These findings suggest that delphinidin exerts anti-metastatic effects in CRC cells by inhibiting integrin/FAK signaling and indicate that miR-204-3p may play an important role in CRC metastasis.

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