HER Story

In 2000, after working for a few years, I returned to school. I went to M. D. Anderson to join Dr. Mien-Chie Hung's lab for my Ph.D. study in cancer biology. As my education background in Taiwan was chemistry and biochemistry, I had very little idea about molecular biology. Every gene name was novel and sometimes ridiculous to me. I was given a beginner’s project: transfecting a DNA plasmid into a cell line and then running a Western blot to check protein expression. That was pre-Google time, I had to check the medical dictionary to find out what "transfect", "plasmid", and "cell line" were. As the first step, I asked for the DNA to use and received a tube labeled as "pcDNA3.1-NeuT", a new term to me. It took me a while to understand that it was a circular DNA inserted with a gene called NeuT… so what did that mean? Again, someone out of his kindness explained to me that it was a rat gene called Neu but carrying a mutation in Transmembrane domain. In the literature, Neu had another name "HER2", and the third name "Erbb2".

All of these were so confusing. Why did these great biologists want to mess up a poor graduate student's mind? It was beyond ridiculous. I missed those days studying chemistry, in which the name of every compound followed strict rules. You’d know the compound’s structure by just reading its name. Why is there no such system in molecular biology? Nevertheless, I picked these nonsense stuffs up and memorized all of them over time, and tried to speak like a pro. I transfected NeuT plasmid into mouse fibroblasts ("NIH3T3") to see how the phenotypes of the cells changed. After six months, I felt I was on the track.

Dr. Hung's lab was incredible- there were more than fifty people- yes you hear it right, 50. Therefore, even though Dr. Hung was so successful in getting funded, the research resource was always tight, as there were so many people competing for it. Everyone worked like crazy and tried to attract Boss' attention on his/her projects. It was a pressure cooker. However, one thing separated Dr. Hung's lab from other big lab: he insisted that no two postdoc should work on the same project. The direct (and vicious) competition was totally banned, almost like a taboo. Because of that, until the time I was about to leave, the pressure cooker never turned to a shark tank.

I got some preliminary results from the NeuT project, and happily thought that it could result in my very first publication. However, someone kindly reminded me: the counterpart of NeuT mutation had never been found in the human NEU gene (a.k.a. HER2/Neu), so my results could be totally irrelevant to human cancer- and who cares about rat cancer? This kept me stressed for a while. Finally we stretched and decorated it as "the activated HER2/Neu" and published it anyway (in case you are interested, see [1] in reference). However, I always wondered why this lab kept using the NeuT gene.

Upon the time I was preparing to graduate, my friend asked me if I wanted to know the origin of NeuT. Of course, I said. He handed me over a book, "Natural Obsession" [2]. He was a little surprised that I did not know the story about my mentor.  As soon as I read through it, many mysteries were revealed. To understand it all, we needed to go back to '80s.

The decade is one of the most exciting periods in cancer research. Every day an oncogene emerged, like the Cambrian explosion. Among all the oncogene hunters, Robert Weinberg was the bright star at that time. It was also the decade that Taiwanese scientists were at the center stage of these discoveries (for example, Wen-Hua Lee found Rb gene). In 1982, Chiaho Shih, a graduate student in Weinberg Lab, discovered the very first oncogenic mutation, HRAS, in human cancer. This ignited the competition for finding the second oncogene. Meanwhile, by "fishing" the gene homologous to avian erythroblastosis oncogene B (ERBB) in human cells, EGFR gene was discovered. The same strategy could be applied to searching for new oncogene. In fact, the earlier fishing results suggested the existence of an ERBB homologous with protein size 185 kDa, which was named ERBB2. Another group found it independently, naming it human EGF Receptor 2, i.e., HER2 (so EGFR became HER1). It was highly expressed in several types of cancer cells. The eyes of all gene hunters were on this one now.

Weinberg wanted to begin his winning track by finding the mutation in HER2, even when there was no consensus on its name yet. He needed the best one to do the job, so he summoned a fresh Ph.D. from the nearby Brandeis University: Mien-Chie "Magic Hands" Hung (It's a real nickname).   

A preliminary study in Weinberg’s lab showed that a rat neuroblastoma cell line expressed a Erbb2-homologous gene, which was named Neu (Neuroblastoma). Years later, this one was characterized as the rat version of HER2/ERBB2. Therefore, it got the third name Neu (and sometimes p185 was counted as the fourth). Mien-Chie used the conventional method: preparing DNA library from the rat cancer cells, "fishing" the one containing HER2-homologous sequences, analyzing the DNA sequence, and then aligning all pieces together. The hope was that a novel mutation can be found during such "chromosome walking" process.

On paper, it was a very straightforward approach. Neu is no doubt a receptor tyrosine kinase by protein structure and exhibits kinase activity. Everyone expected that the mutation would appear in either ligand-binding domain or kinase domain. Therefore, you started walking the chromosome from either N-terminal or C-terminal positions of the protein and would find it quickly. However, Neu protein had two suspicious or risky features. First, since its discovery, no one could ever find its ligand. Second, it is a super big protein. Mien-Chie tried walking from both ends but reached nowhere. The more the chromosome walking advanced, the slower it became. Two years has passed but he still got nothing; the frustration from this project and some family issues stressed him out terribly. He needed a paper in a top-tier journal to get a faculty job in the top-tier institutes, like the two in Boston. At the same time, Mien-Chie was very alarmed that Bob Weinberg LOVED to make postdocs compete on the same projects. Bob told him, "You need to learn how to survive". This philosophy of research management totally made his lab a shark tank. As the progress was terrible, he began to worry that someone would show up in the scene and grab his project.

He would not imagine that his nightmare would come true so soon.

As Mien-Chie struggled in the darkness, a shiny new star was rising in Weinberg's lab. She was still a graduate student, but her talents and brightness had been well recognized. It would be an unforgettable name for Mien-Chie: Cornelia "Cori" Bargmann.

Since HER2 had been known for the second oncogene, Cori had paid attention to Mien-Chie's project. She proposed a bold move: using the contemporary cutting-edge technology, reverse transcription to get cDNA from HER2 RNA, and then sequence the cDNA. This would effectively reduce the walking distance, a truly brilliant idea, so Weinberg agreed immediately. Of course, she needed every inch of available HER2 sequence data, thus Weinberg demanded Mien-Chie to hand them over. He almost collapsed. This moment became a permanent trauma. He lost his first opportunity to publish in the “big three" journals (Nature, Science, Cell) for the full credit. It would take him another 15 years to make that happen [3].

Cori got what she wanted and did not wait to start the work. It went smoothly, and she successfully identified the mutation in rat Neu gene. Unexpectedly, it was located in the middle of a transmembrane domain, almost equally far away from either the N- or C-terminus of the protein. No wonder Mien-Chie has such a hard time! That was a novel mechanism; the mutation forced Neu to dimerize and activate kinase activity. It was named NeuT in Weiberg's lab. Cori proudly published these results in Cell as the first author, with Mien-Chie as the second [4]. She found the second oncogenic mutation!

But things did not follow her playbook.

Cori was supposed to be remembered as the discoverer of the second oncogenic mutation in the history of cancer research. However, there was a tiny problem: the mutation of HER2 was never found in human cancer. Since her publication in Cell, a few groups had put efforts to look for the counterpart in human cancer, but nothing was found. It was later revealed that the HER2 gene was amplified in human cancer instead of mutation [5]. Gene amplification became the second known mechanism of oncogenic signaling. The implication of Cori's finding was suddenly very limited, just an episodic case in a weird rodent tumor. In recent years, as genes are sequenced extensively, many people tried to identify rare mutations in HER2. All were found in either N- or C-termini, mostly in the kinase domain. None of them are in the transmembrane domain. Still, zero. None. [6]  

Cancer is always smarter than researchers. NeuT fooled Cori and left Mien-Chie traumatized. Cori got her Ph.D. but swiftly switched her career to neuroscience without looking back. Mien-Chie moved to Houston to start his own laboratory in M. D. Anderson, where he became so successful but insisted that lab mates should not compete on the same project. I always thank him for bringing NeuT to Houston and preventing his lab from becoming a shark tank. My days there were intense and stressful, but they were still some of the best times in my life.

Only after leaving Mien-Chie’s lab, I could put all the pieces of the puzzle together- the reason for the many names of HER2, the weird mutation of NeuT, and why we were the only group still using it, and his style of managing research. I got to understand what was behind many emotional moments during my five years there. On the other hand, I always wondered who discovered the gene amplification of EGFR (HER1) as the alternative oncogenic mechanism? If Mien-Chie and Cori got a chance to get advice from that person, would that change their luck or even their style of supervising research?

After two years in NCI, I realized that I am working for one of the discovers of EGFR amplification. That's my boss Glenn [7].   

Reference 

  1. https://www.nature.com/articles/1207485
  2. https://www.amazon.com/Natural-Obsessions-Pa-Natalie-Angier/dp/0395924723
  3. https://www.sciencedirect.com/science/article/pii/S0092867404003022
  4. https://www.sciencedirect.com/science/article/pii/0092867486907798
  5. https://aacrjournals.org/cancerres/article/48/6/1517/493519/Sporadic-Amplification-of-the-HER2-neu
  6. https://aacrjournals.org/clincancerres/article/20/1/68/78413/A-High-Frequency-of-Activating-Extracellular
  7. https://www.science.org/doi/10.1126/science.6200934