This is not an easy topic. Therefore, I am going to divide it into two parts. In the first, I will make a feeble attempt to provide a brief description of IGF-1…focusing mainly on what it means for myeloma patients. In the second part, I will bring up a couple of things that we can do to give it a big whack…
IGF-1 stands for insulin-like growth factor 1. As its name implies, its molecular structure is similar to that of insulin, but its main purpose is not to decrease blood glucose levels but rather to stimulate the growth of normal cells (IGF-1 affects almost every cell in the body, I read)…and also–and here we get to the crux of the matter–the growth and survival of cancer cells.
Why am I interested in this growth hormone? Well, because in May I read a “Blood” abstract (see below), which showed that there is a connection between IGF-1 and myeloma cell proliferation…and this is not a super recent discovery, by the way. If you do a PubMed search, you will find studies on this issue that date back to the 1990s.
For instance, a 2000 French study (full study: http://tinyurl.com/ybwyngc) tells us that an important mediator of bone remodelling, IGF-1, has been shown to stimulate the proliferation of human myeloma cells. The researchers add that the mechanism involved is still a mystery…but after all, understanding the intricate workings of this process does not matter one whit to me…heck, I probably wouldn’t understand it anyway!
What matters to me is that there is a connection between IGF-1 and myeloma cell proliferation and survival, as we can read in a more recent (2008) study (abstract: http://tinyurl.com/kmbqcs): IGF-1 and IL-6 promote the proliferation and survival of multiple myeloma cells.
Sherlock (grazie!) sent me the full study, from which I took the following excerpt: the IGF-1 receptor (IGF-1R) is universally expressed on multiple myeloma cells, and higher expression levels are correlated with poorer patient prognosis. Okay, I admit that I merely skimmed the text, in part because I don’t have a huge amount of time, but also because this is an extremely complicated technical study, the splitting-headache kind….I finally had to set it aside and give up, at least for now.
Anyway, if you need more convincing that IGF-1 is bad news for us, here is the abstract to a May 2009 study published in “Blood”: http://tinyurl.com/ydl95ye Of the five myeloma growth factors (or MGFs) examined, IGF-1 was the major one…even worse, if possible!, than our old archenemy, IL-6. And here is a bad bit concerning prognosis: Of the investigated MGFs and their receptors, only expressions of IGF-1R and IL-6R in multiple myeloma cells (MMCs) of patients delineate a group with adverse prognosis. Ouch.
I should note that IGF-1 isn’t all bad. It is essential for normal growth and development (but of course we aren’t kids anymore!)…and I also found a study showing that it had a beneficial effect on cardiomyopathic hamsters: http://tinyurl.com/y99h3yo
Okay, but, in the case of multiple myeloma, high levels of IGF-1 = a bad thing. Clearly.
That’s it for today. More tomorrow, providing I can finish my research for Part II…
Last but not least: sweet little Jaymun, you hang in there! (see Jaymun’s journey)