Two complementary studies from the Faculty of Medical and Health Sciences at Tel Aviv University, in collaboration with the European Institute of Oncology in Milan, have extensively examined the characteristics of cells with an abnormal number of chromosomes - known as aneuploid cells - and raised findings that may advance new cancer treatments.

Targeting Aneuploid Cancer Cells

According to the researchers: "a significant portion of cancer cells are aneuploid, and this trait distinguishes them from healthy cells. Our work focuses on the vulnerabilities of aneuploid cells, with the aim of promoting new strategies for eliminating cancerous tumors".

The researchers: "In our studies, we found that aneuploidy increases the sensitivity of cancer cells to certain types of anticancer drugs".

The studies were led by Prof. Uri Ben-David and doctoral student Johanna Zerbib from the Department of Human Molecular Genetics and Biochemistry at the Faculty of Medical and Health Sciences at Tel Aviv University, in collaboration with Professor Stefano Santaguida and doctoral student Marica Rosaria Ippolito from the University of Milan in Italy, along with researchers from both laboratories. Additional contributors included research teams in Israel, Italy, the USA, and Germany. Two articles based on the research were published in the prestigious journals Cancer Discovery and Nature Communications.

Prof. Ben-David explains: "In the nucleus of a healthy human cell, there are 23 pairs of chromosomes - half from the father and half from the mother, totaling 46. One of the characteristics of cancer cells, which distinguishes them from healthy cells, is an abnormal number of chromosomes, resulting from improper cell division - a phenomenon known as aneuploidy. We believe that if we can identify specific vulnerabilities of aneuploid cells, we can promote new cancer treatments that target these weaknesses and do not harm healthy cells. About three years ago, we published a comprehensive study in the journal Nature, in which we classified approximately 2,000 malignant cells from various cancer types according to their level of aneuploidy, and examined how they respond to various existing treatments. In that study, we found new vulnerabilities in aneuploid cells. However, the study had a limitation: because the cells came from different types of cancer, it was difficult to isolate the impact of aneuploidy itself from the effect of other genetic differences between the tumors".

Consequently, the researchers chose to conduct a new study using human cell cultures that are all genetically identical (i.e., derived from the same individual). The researchers added a substance to the cultures that disrupts the separation of chromosomes, causing some of them to become aneuploid. Since the cells were genetically identical, the only difference between them after the procedure was the level of aneuploidy - i.e., the number of chromosomes. To thoroughly examine the effects of aneuploidy, the cells underwent various characterization processes: DNA and RNA sequencing, measuring the levels of all the proteins in the cell, assessing the response to 6,000 different drugs, as well as a process known as CRISPR screening - systematically impairing each gene in the genome to identify genes that are essential in the cells. The researchers noted: "In this way, an extensive and unique database of the characteristics of aneuploid cells was established, which can serve as a foundation for future studies, as well as for developing biological markers that predict cancer patients' responses to specific drugs and treatments".

How to Exploit Cell Vulnerabilities for Cancer Therapy?

As part of the comprehensive survey, a mechanism called MAPK (mitogen-activated protein kinase) was observed, which is especially crucial for repairing DNA damage in aneuploid cells. The study also showed that this mechanism is relevant for various types of aneuploid cells—among them cancer cells in cultures and in human tumors. Prof. Ben-David: "We found that aneuploid cancer cells increase the activity of DNA repair mechanisms due to the large amount of DNA damage present; and we discovered a mechanism that could allow us to exploit this characteristic to target these cancer cells".

To test their hypothesis, the researchers disrupted the MAPK pathway in the cells and then examined their sensitivity to chemotherapy. The findings were promising: aneuploid cells in which this mechanism was disrupted were much more sensitive to chemotherapy (which causes DNA damage) compared to cells with a normal number of chromosomes. The researchers then sought to determine whether there is a correlation between this pathway and the clinical response of cancer patients to chemotherapy treatments. For this purpose, they relied on data from clinical treatments and experiments where human tumors were implanted in mice, and the results were clear: the higher the activity of the pathway in the aneuploid tumors, the greater their resistance to chemotherapy.

The comprehensive characterization of aneuploid cells also revealed another significant finding: these cells, which contain more chromosomes than normal cells, also necessarily include a larger amount of DNA, leading to excess production of RNA and proteins. The cell, seeking to compensate for this overproduction, attempts to silence and degrade excess RNA and proteins.

Paving the Way for Future Treatments

Johanna Zerbib noted: "Here we found another vulnerability of aneuploid cells, based on our hypothesis that these cells are more sensitive to existing drugs that inhibit protein degradation. To validate this hypothesis, we exposed cell cultures to such drugs and analyzed clinical data from patients treated with a drug that inhibits protein degradation in the cells. The findings supported the hypothesis - that aneuploidy increases the sensitivity of cancer cells to these drugs".

Prof. Ben-David concluded: "In our research, we identified two significant vulnerabilities characterizing aneuploid cells - cells with chromosomal changes, commonly found in cancer cells. The first is a mechanism essential for repairing DNA damage, where impairment significantly increases the sensitivity of aneuploid cells to chemotherapy; the second is the increased degradation of excess RNA and proteins, which can be targeted, among other things, with inhibitors that are already in clinical use. We also created an extensive database of characteristics of aneuploid cells that can serve to predict cancer patients' responses to various drugs and treatments. We believe that our research findings will benefit many researchers, oncologists, and patients in the years to come".

The breakthrough was achieved by a team of investigators from Tel Aviv University led by doctoral student Omer Ben Barak-Dror, under the joint supervision of Prof. Yuval Nir from the Department of Physiology and Pharmacology, Faculty of Medical and Health Sciences, Sagol School of Neuroscience, and the Department of Biomedical Engineering; and Prof. Israel Gannot from the Department of Biomedical Engineering. Other team members include Dr. Michal Tepper, Dr. Barak Hadad, Dr. Hani Barhum, and David Haggiag. The research was published in the journal Communications Medicine.

An Eye-Opening Discovery

Prof. Nir explains: "It is often said that the eyes are the windows to the soul". Indeed, pupil size changes constantly, dilating or contracting to regulate the amount of incoming light, while providing valuable clinical information. We all know that our pupils get smaller in bright light and larger in darkness, but this is only one reason why pupils change size. They also dilate when we’re stimulated, for example when we react to a sudden event or when we are in pain. In such cases, our autonomic nervous system serves as an alarm and prepares us to take action. Tracking pupil size and eye movements can be critical in many clinical situations. However, until now this has been limited to open-eye scenarios. No method allowed anyone to do this when their eyes were closed.

The new research describes innovative technology that combines short-wave infrared (SWIR) imaging with deep learning algorithms to perform touchless pupillometry and eye tracking behind closed eyelids. “To establish and validate our technology, we focused on the pupillary light reflex (PLR) when the pupil constricts in response to a sudden flash of light, and then dilates back to normal. This is a basic reflex that occurs symmetrically across the two eyes in healthy people. We performed experiments testing our technology on the closed eye while comparing the results to the open-eye data,” said Omer Ben Barak-Dror, lead author of the study at Tel Aviv University.

Eye Spy: Monitoring Pupils While You Sleep

Profs. Nir and Gannot add: "Our method can successfully track the precise dynamics of the pupillary light reflex in closed-eye conditions, revealing the changes in pupil size following each light flash in individual subjects, and also accurately estimating where the eye gaze is directed to, within a few degrees accuracy. The system operates at wavelengths where light has its maximum depth of penetration in biological tissue, and by analyzing the data using deep learning algorithms, we can go beyond what is typically possible with standard methods of near-infrared imaging". Dr. Tepper adds that the information collected using continuous touchless monitoring is a critical element of the patient’s electronic medical record (EMR) and helps with decisions concerning optimal medical treatment.

The investigators concluded: "Our technology, backed by a patent application, paves the way for developing devices with wide-ranging clinical and commercial applications in domains ranging from sleep medicine, through monitoring sedation level and intraoperative awareness in anesthesia, to assessing pain and reactivity in unresponsive patients or neurology intensive care and trauma wards".

The study was supported by grants from the Zimin Foundation and the breakthrough technology program of the Israeli Ministry of Science and Technology.

Researchers from the Sonia & Marco Nadler Institute of Archaeology at Tel Aviv University used various modern technologies, including drones, remote sensing, and 3D digital modeling, to generate the first objective, quantified analysis of the Roman siege system at Masada. Findings indicate that contrary to the widespread myth, the Roman army's siege of Masada in 73 CE lasted no more than a few weeks.

The study was conducted by the Neustadter expedition from TAU's Sonia & Marco Nadler Institute of Archaeology, headed by Dr. Guy Stiebel, together with Dr. Hai Ashkenazi (today Head of Geoinformatics at the Israel Antiquities Authority), and PhD candidates Boaz Gross (from Tel Aviv University and the Israeli Institute of Archaeology) and Omer Ze'evi-Berger (today at the University of Bonn). The study is part of the expedition's extensive mission, implementing advanced tools and posing fresh questions, to attempt a new understanding of what really happened at Masada. The paper was published in the Journal of Roman Archaeology.

Dr. Guy Stiebel

New Tech Reveals Old Secrets

Dr. Stiebel: "In 2017 my expedition renewed, on behalf of TAU's Sonia & Marco Nadler Institute of Archaeology, excavations at Masada – a world-famous site explored extensively since the early 19th century and throughout the 20th century. Our expedition sets forward several new questions and implements many novel research tools that were not available to previous generations of archaeologists. In this way, we intend to obtain fresh insights into what actually happened there before, during, and after the Great Jewish Revolt. As part of this extensive project, we devote much scholarly attention to the site’s surroundings. We use drones, remote sensing, and aerial photography to collect accurate high-resolution data from Masada and its environs, emphasizing three aspects: the water systems, the trails leading to and from the palatial fortress, and the Roman siege system. The collected information is used to build 3D digital models that provide a clear and precise image of the relevant terrains. In the current study, we focused on the siege system, which, thanks to the remote location and desert climate, is the best-preserved Roman siege system in the world".

3D model of Tower 7 and the circular feature to its left, view to the west. Photo Credit: The Neustadter Masada Expedition, taken from the Journal of Roman Archaeology.

Dr. Stiebel adds: "For many years, the prevailing theory that became a modern myth asserted that the Roman siege of Masada was a grueling three-year affair. In recent decades researchers have begun to challenge this notion, for various reasons. In this first-of-its-kind study, we examined the issue with modern technologies enabling precise objective measurements".

3D model of the ramp/staircase, view to the southwest. Photo Credit: The Neustadter Masada Expedition, taken from the Journal of Roman Archaeology.

The researchers used drones carrying remote sensors that provided precise, high-resolution measurements of the height, width, and length of all features of the siege system. This data was used to build an accurate 3D digital model, enabling exact calculation of the structures' volume and how long it took to build them.

What Really Happened at Masada?

Dr. Ashkenazi: "Reliable estimates are available of the quantity of earth and stones a Roman soldier was able to move in one day. We also know that approximately 6,000-8,000 soldiers participated in the siege of Masada. Thus, we were able to objectively calculate how long it took them to build the entire siege system – eight camps and a stone wall surrounding most of the site. We found that construction took merely about two weeks. Based on the ancient historical testimony it is clear that once the assault ramp was completed, the Romans launched a brutal attack, ultimately capturing the fortress within a few weeks, at the most. This leads us to the conclusion that the entire siege of Masada lasted no more than several weeks".

Tower 10 and the wall abutting it. Photo Credit: The Neustadter Masada Expedition, taken from the Journal of Roman Archaeology.

The Truth Behind Masada’s Brief Siege

Dr. Stiebel: "The narrative of Masada, the Great Jewish Revolt, the siege, and the tragic end as related by Flavius Josephus, have all become part of Israeli DNA and the Zionist ethos, and are well known around the world. The duration of the siege is a major element in this narrative, suggesting that the glorious Roman army found it very difficult to take the fortress and crush its defenders. For many years it was assumed that the siege took three long years, but in recent decades researchers have begun to challenge this unfounded belief. In our first-of-its-kind study, we used objective measurements and advanced technologies to clarify this issue with the first data-driven scientific answer. Based on our findings we argue that the Roman siege of Masada took a few weeks at the most.".

"As empires throughout history have done, the Romans came, saw, and conquered, quickly and brutally quelling the uprising in this remote location. Our conclusion, however, detracts nothing from the importance of this historical event, and many baffling questions remain to be investigated"- Dr. Stiebel.

He continues: "For example: Why did the Romans put so much effort into seizing this remote and seemingly unimportant fortress? To answer this and many other intriguing questions we have initiated a vast, innovative project in and around Masada – collecting data and analyzing it thoroughly in the labs of TAU's Sonia & Marco Nadler Institute of Archaeology, in collaboration with other researchers, to ultimately shed new light on the old enigma: What really happened at Masada?"

The study, led by Dr. Marta Acácio as part of her post-doctoral research in Dr. Orr Spiegel's laboratory at Tel Aviv University’s School of Zoology, was conducted in collaboration with Prof. Noa Pinter-Wollman of the University of California, Los Angeles (UCLA) and several other researchers. The findings were published in the prestigious journal PNAS.

Dr. Marta Acácio.

Dr. Orr Spiegel. releasing tagged vultures (Photo credit: Tovale Solomon).

The Eagle Has Landed

Dr. Spiegel explains: “Vultures are a locally endangered species in Israel, with only about 200 individual vultures remaining. They are closely monitored to determine the best possible conservation methods. We thought about what else could be gleaned from the extensive database we have accumulated over the years and agreed it would be interesting to explore how vultures age. Tracking the same individuals in the wild over many years is often very challenging. However, the transmitters we use to monitor the population provided a rare opportunity to observe the aging process in vultures specifically and in animals generally”.

The researchers utilized a database accumulated over 15 years from GPS devices attached to 142 vultures that tracked them for periods of up to 12 years. The vulture, a social bird, sleeps in roosts on cliffs. By cross-referencing the vultures’ ages with the GPS data on their roosting sites, the researchers discovered that as the vultures aged, they increasingly preferred to stay at the same roosting site.

Aging vulture being monitored (Photo credit: Tovale Solomon).

Home Sweet Home

Dr. Spiegel: “It turns out that aging vultures behave a bit like humans and are more inclined to stay at home. When they're young, vultures like to explore new sites and frequently move between places; the likelihood that a young vulture will sleep at the same site two nights in a row is low. When they reach adolescence at the age of five, this behavior stabilizes, and as adults they spend 50 percent of their nights at the same site and the other 50 percent at other sites. When they are old, from the age of 10 onwards, they no longer have the energy to be 'out and about', and return consistently to the same site. Furthermore, when adult vultures do change sites, they do so in a predictable pattern: for example, one night in Ein Avdat, the next in the Small Crater, and the next in Nahal Golhan, following a fixed order. Of course, it could be argued that older vultures move less not because they are old, but because they avoid taking risks in the first place, which is how they reached the age they did. But here we are talking about the exact same individual birds: those who were adventurous at the age of five became more sedentary by age ten”.

Elder Eagles' Poisoning

According to Dr. Spiegel, these fascinating findings on the aging of birds also have very practical implications for conservation efforts. “This new study can help us better protect vultures’ roosting sites in the wild. Additionally, we have now seen that older vultures have fewer social connections, which can help us to prevent poisoning. The transmitters are connected to a system that sends an alert to the Israel Nature and Parks Authority, and to us by phone, if the vulture is not moving or has landed in a dangerous place, indicating that it may have been poisoned.

Collecting dead vultures following poisoning in the Golan Heights by Nature and Parks Authority rangers (Photo credit: Nature and Parks Authority).

Unfortunately, this happens frequently. The danger arises when a vulture descends on a poisoned goat carcass, not knowing that a farmer has poisoned the carcass in order to kill stray dogs. Being social birds, vultures do not come down alone, leading to the risk of dozens of vultures dying at once. Understanding how wide the poisoned vulture’s social circle is will significantly help in mitigating the damage”.

It is important to note that vultures play an important ecological role in the disposing of carcasses. Studies have shown that the extinction of vultures ultimately leads to the loss of human lives, due to the rise of diseases such as rabies. In India, for example, a recently published study revealed that the extinction of vultures due to poisoning resulted in the deaths of half a million people over the course of five years.