Cancer cells use two pathways to sense and move in tight quarters

COVER IMAGE CAPTION: Hung et al. describe two cooperating signaling modules by which cells sense and traverse confined spaces. Signaling output is optimized through complex feedback loops ultimately leading to efficient cell motility. Artist Jun Cen ( ) depicts a small diver exploring confined migration, which is symbolized by the large size and tangled arms of the octopus trying to squeeze into the cave.

Hung et al. describe cooperating signaling modules used by cells to sense and traverse confined spaces. Artist Jun Cen ( ) show a  small diver exploring confined migration symbolized by the tangled arms of the octopus trying to squeeze into the cave.

Like a bicycle messenger weaving through busy city streets, cancer cells are skilled at maneuvering through microenvironments. Researchers know they use complex signally pathways to move through and sense their surroundings, but exactly how these pathways worked was unclear.  Now, researchers from the Konstantinos Konstantopoulos laboratory at Johns Hopkins University have determined that both calcium and the cell protein myosin play a role in a cooperative feedback loop that makes cancer cells champions of  motility even in a tight squeeze  Their work appears in the May 17, 2016 journal Cell Reports, and an artist’s interpretation of the study graces the journal’s cover.

Wei-Chien Hung was the lead author on a study that used microfabricated growth chambers featuring narrow channels that the cells had to move through.  As the cancer cells migrated through the device, they had to squeeze and stretch to fit into confined spaces. As the cell membrane stretched, it caused special stretch-activated channels (called Piezo1 channels) to open. When the channels opened, calcium ions could flow through the cell membrane into the cell. The additional calcium ions set off a cascade of biochemical events leading to the activation of myosin.

As a molecular motor, myosin drove the cancer cells to move forward.  Myosin also served as a sensor that directly responded to external force and stretched the membrane.  This opened the channels, allowing more calcium ions to flow in; myosin in turn was further activated and so on.  This feedback system maximized the signaling output of the two sensors.

Screen Shot 2016-05-24 at 3.57.00 PMKonstantopoulos, professor and chair of Department of Chemical and Biomolecular Engineering and an affiliated faculty member of Johns Hopkins Institute for NanoBioTechnology, says that the two ways of sensing the environment and signaling movement in a microenvironment makes the motility of cancer cells extremely efficient and highly effective in confined spaces, such as what might be found inside of a tumor cell mass. These two pathways also present two potential targets on which cancer researchers can focus further investigation in order to prevent cancer cell migration.

Other authors on the paper include Jessica Yang, Christopher Yankaskas, Joy T. Yang and Jin Zhang. The research was funded in part by the NIH and the American Heart Association.

Written by Mary Spiro. For media inquiries regarding INBT, contact Mary Spiro at


Konstantopoulos to present distinguished lecture on tumor cell migration

Biomedical Engineering 8 5 x 11 4-7Biomedical Engineering 8 5 x 11 4-7Biomedical Engineering 8 5 x 11 4-7Professor and Chair of the Department of Chemical and Biomolecular Engineering, Konstantinos Konstantopoulos will present a distinguished lecture for the Department of Biomedical Engineering on Monday, April 7 at 4 p.m. in the Mason Hall Auditorium on the Homewood campus of Johns Hopkins University.  His talk. “Joining Forces with Biology: A Bioengineering Perspective on Tumor Cell Migration,” will reveal some of his laboratory’s current findings on metastasis. The talk is free and open the Johns Hopkins University community. Refreshments follow the lecture.

Here’s the abstract of his talk:

“Understanding the mechanisms of cell migration is a fundamental question in cell, developmental and cancer biology. Unraveling key, physiologically relevant motility mechanisms is also crucial for developing technologies that can control, manipulate, promote or stop cell migration in vivo. Much of what we know about the mechanisms of cell migration stems from in vitro studies using two-dimensional (2D) surfaces. Cell locomotion in 2D is driven by cycles of actin protrusion, integrin-mediated adhesion and myosin-dependent contraction. A major pitfall of 2D assays is that they fail to account for the physical confinement that cells  encounter within the physiological tissue environment. The seminar will challenge the conventional wisdom regarding cell motility mechanisms, and show that migration through physically constricted spaces does not require beta1 integrin dependent adhesion or myosin contractility. Importantly, confined migration persists even when filamentous actin is disrupted. This seminar will also discuss a novel mechanism of confined cell migration based on an osmotic en

Konstantopoulos named BMES fellow

Konstantinos Konstantopoulos (Photo by Mary Spiro)

Konstantinos Konstantopoulos, professor and chair of the Department of Chemical and Biomolecular Engineering at Johns Hopkins University’s Whiting School of Engineering has been named a Fellow of the Biomedical Engineering Society (BMES). Konstantopoulos was one of only nine fellows elected to the Society’s Class of 2012.

BMES states that Konstantopoulos received this honor in recognition of his “seminal bioengineering research contributions involving the discovery and characterization of novel selectin ligands expressed by metastatic tumor cells.”  Formal installation of fellows will take place at the BMES annual meeting  October 24-27 in Atlanta.

Konstantopoulos is an affiliated faculty member of Johns Hopkins Institute for NanoBioTechnology. He is also a project leader with the Johns Hopkins Physical Sciences-Oncology Center. Together with Martin Pomper, a School of Medicine professor of radiology and co-principal investigator of the Johns Hopkins Center of Cancer Nanotechnology Excellence, Konstantopoulos is researching mechanochemical effects on metastasis.

Specifically, his work investigates the effects of fluid mechanical forces at different oxygen tension microenvironments on tumor cell signaling, adhesion and migration. Fluid flow in and around tumor tissue modulates the mechanical microenvironment, including the forces acting on the cell surface and the tethering force on cell-substrate connections. Cells in the interior of a tumor mass experience a lower oxygen tension microenvironment and lower fluid velocities than those at the edges in proximity with a functional blood vessel, and are prompted to produce different biochemical signals. These differential responses affect tumor cell fate that is, whether a cell will live or die, and whether it will be able to detach and migrate to secondary sites in the body.

According to the BMES website, members who demonstrate exceptional achievements and experience in the field of biomedical engineering, as well as a record of membership and participation in the Society, have the opportunity to become fellows. Fellows are selected and conferred  by the BMES board of directors through a highly selective process. Nominations for each of these categories may be made by Society members and the board of directors.

Learn more about research in the Konstantopoulos Lab here.



Tumor cells change when put into a ‘tight spot’

Konstantinos Konstantopoulos addresses audience at 2012 NanoBio Symposium. Photo by Mary Spiro/JHU

“Cell migration represents a key aspect of cancer metastasis,” said Konstantinos Konstantopoulos, professor and chair of the Department of Chemical and Biomolecular Engineering at Johns Hopkins University. Konstantopoulos was among the invited faculty speakers for the 2012 NanoBio Symposium.

Cancer metastasis, the migration of cancer cells from a primary tumor to other parts of the body, represents an important topic among professors affiliated with Johns Hopkins Institute for NanoBioTechnology. Surprisingly, 90 percent of cancer deaths are caused from this spread, not from the primary tumor alone. Konstantopoulos and his lab group are working to understand the metastatic process better so that effective preventions and treatments can be established. His students have studied metastatic breast cancer cells in the lab by tracking their migration patterns. The group has fabricated a microfluidic-based cell migration chamber that contains channels of varying widths. Cells are seeded at one opening of the channels, and fetal bovine serum is used as a chemoattractant at the other opening of the channels to induce the cells to move across. These channels can be as big as 50 µm wide, where cells can spread out to the fullest extent, or as small as 3 µm wide, where cells have to narrowly squeeze themselves to fit through.

A current dogma in the field of cell migration is that actin polymerization and actomyosin contractility give cells the flexibility they need to protrude and contract across a matrix in order to migrate. When Konstantopoulos’s students observed cells in the wide, 50 µm-wide channels, they saw actin distributed over the entirety of the cells, as expected. They also observed that when the cells were treated with drugs that inhibited actin polymerization and actomyosin contractility, they did not migrate across the channels, also as expected.

However, when the students observed cells in the narrow, 3 µm-wide channels, they were surprised to see actin only at the leading and trailing edges of the cells. Additionally, the inhibition of actin polymerization and actomyosin contractility did not affect the cells’ ability to migrate.

“Actin polymerization and actomyosin contractility are critical for 2D cell migration but dispensable for migration through narrow channels,” concluded Konstantopoulos. The data challenged what many had previously believed about cell migration by showing that cells in confined spaces did not need these actin components to migrate.

These findings are indeed important in the context of cancer metastasis, where cells must migrate through a heterogeneous environment of both wide and narrow areas. Konstantopoulos’s data gives a better mechanistic understanding of the different methods cancer cells use to migrate in diverse surroundings.

Future studies in the Konstantopoulos lab will focus on how tumor cells decide which migratory paths to take. INBT-sponsored graduate student Colin Paul has developed an additional microfluidic device that contains channels with bifurcations. He hopes to determine what factors guide a cell in one direction versus another. The Konstantopoulos lab hopes to continue to understand exactly how tumor cells migrate so that new therapies can eventually be developed to stop metastasis.

Story by Allison Chambliss, a Ph.D. student in the Department of Chemical and Biomolecular Engineering with interests in cellular biophysics and epigenetics.

Watch a video related to this research here.

Konstantopoulos reported these findings in October 2012 The Journal of the Federation of American Societies for Experimental Biology.  Read the article online here.


Breast cancer highlighted at Homewood mini-symposium

A tumor cell breaking free and entering the blood stream. (From animation by Ella McCrea, Nathan Weiss and Martin Rietveld)

Breast cancer will be topic of at least two of the talks planned for a mini-symposium October 10 on the Homewood campus.

UPDATED: Click here for updated list of talk titles.

Students from Johns Hopkins Physical Sciences-Oncology Center (PSOC) and Center of Cancer Nanotechnology Excellence (CCNE) will hold their second mini-symposium of the year on October 10 at 9 a.m. in Hackerman Hall Auditorium. The symposia, scheduled each spring and fall on the Homewood campus, encourage an exchange of ideas between PhD students and postdoctoral fellows associated with these centers. The entire Hopkins community is invited to attend, and no RSVP is required.

Some of the talk titles include, from the department of Chemical and Biomolecular Engineering, “The Pulsing Motion of Breast Cancer Cell is Regulated by Surrounding Epithelial Cells” presented by Meng Horng Lee, a PSOC postdoctoral fellow in the Denis Wirtz lab; “Breast Tumor Extracellular Matrix Promotes Vasculogenesis” presented by Abigail Hielscher, a postdoctoral fellow in the Sharon Gerecht lab; and “Mucin 16 is a Functional Selectin Ligand on Pancreatic Cancer Cells” given by Jack Chen, a pre-doctoral fellow in the lab of Konstantinos Konstantopoulos. Additional speakers include postdoctoral fellow Pei-Hsun Wu, PhD, a from the Wirtz Lab and Koh Meng Aw Yong, a pre-doctoral student affiliated with Princeton University’s Physical Sciences-Oncology Center.

The purpose of these twice a year, student run mini-symposia is to facilitate communication among researchers working in laboratories studying the mechanistic aspects of cancer spread (i.e., those affiliated with the PSOC) and those working on novel means of using nanotechnology for cancer diagnosis or treatment (i.e., those associated with the CCNE). Anjil Giri coordinated the fall mini-symposium, a PSOC pre-doctoral fellow in the Wirtz lab , with Erbil Abaci, a PSOC pre-doctoral fellow with in the Gerecht lab. Visit the INBT website ( for further details, as additional speakers and talk titles will be announced.

Nanobio postdocs offer trusted tips on getting grant money

Photo illustration by Mary Spiro.

Three postdoctoral fellows from Johns Hopkins Institute for NanoBioTechnology will offer a one-hour crash course in how to get those research dollars; July 27, 11 a.m. Krieger 205. Free for Hopkins community.

Funding dollars make the research world go ‘round. Few know that better than postdoctoral fellows, who would be out of work without it. As part of Johns Hopkins Institute for NanoBioTechnology’s last professional development seminar of the summer, three INBT affiliated postdoctoral fellows will offer their sage advice on preparing winning research grants.

Topics to be covered on the basic aspects of grant writing include:

  • knowing when to write a grant
  • identifying funding sources
  • planning a timeline
  • how to structure a competitive proposal
  • do’s and dont’s of grant writing and planning
  • basic science writing tips for conveying ideas clearly and succinctly

This seminar will be led by Eric Balzer, postdoctoral fellow with professor Konstantinos Konstantopoulos (ChemBE); Yanique Rattigan, postdoctoral fellow with professor Anirban Maitra (Oncology/Pathology); and Daniele Gilkes, postdoctoral fellow with professor Denis Wirtz (ChemBE).

For additional information on INBT’s professional development seminar series, contact Ashanti Edwards, INBT’s Academic Program Administrator at