By Michael Antoine
Meet Dr. Carl June. He’s a researcher at Penn Medicine and he wants to give you HIV!…err…kinda. I mean if you have leukemia, he wants to give you HIV!...that sounds even worse. Ummm ok, Dr. Carl June wants to use HIV to treat you if you have cancer. Let me explain.
Acute
lymphoblastic leukemia (ALL) is a cancer of the blood and bone marrow, specifically
affecting lymphocytes, which are commonly known as white blood cells. Like most
cancers, ALL results from DNA damage to genes that are responsible for regulating
cell growth. This DNA damage can be caused by too much UV light exposure,
genetic abnormalities, carcinogenic compounds, or maybe even Taco Bell! (There’s
been some talk of TB using butane, a carcinogenic gas, based preservatives in
their food, but that’s not gonna stop me from devouring cheesy gordita
crunches). Food aside, with these genes rendered nonfunctional, immature
lymphocytes are produced at an uncontrolled rate, eventually crowding out other
healthy blood cells and interfering with their functions. Unfortunately, these
immature lymphocytes are useless against infections and just take up space. ALL
affects roughly 6,000 people per year and is more common in children; making up
about 30% of all pediatric cancer, however it has fairly high rates of
remission. It is less common in adults, but the chance of cure is significantly
reduced due to relapse.
In 2012,
Marshall Jensen was diagnosed with ALL and searched for 2 years for a way to
cure his disease. That was when he was introduced to Dr. Junes experimental
treatment of the disease that involved modifying a patients immune cells using
the human immune-deficiency virus, better known as HIV.
Current
treatments of cancer typically involve some combination of surgery, radiation
therapy, and chemotherapy. Surgery and radiation remain an option as long as
the cancer tumor is localized to one area, however if a tumor metastasizes
(moves to other parts of the body), chemotherapy becomes the best option, which
is the common choice against ALL. Chemotherapy involves administering the
patient a drug cocktail in order to kill the cancer, however noncancerous cells
can be incidental targets of these drugs as well including “blood-forming cellsin the bone marrow; hair follicles; and cells in the mouth, digestive tract,and reproductive system. Some chemo drugs can damage cells in the heart,kidneys, bladder, lungs, and nervous system.”
It’s a broad-spectrum lethal treatment where you’re essentially hoping
the cancer gives out before the patient does.
Dr. June’s treatment avoids causing the patient significant suffering
and appears to be very effective based on early trials. In a recently released
study published in The New England Journal of Medicine in Oct 2014, Dr. June
treated 30 ALL patients, 23 of which are still alive with 19 of them in
remission. As of November 2014, Mr. Jensen is at home with his ALL in remission
as well.
So how does this treatment work? It starts by drawing large
numbers of T-lymphocytes out of the body, and then reprogramming them using an
altered form of HIV. Why T-lymphocytes? These cells are critical for an
effective immune response and can be divided into helper and killer T-cells.
Normally these cells are responsible for finding and ridding the body of cancerous
cells. So what happened? It’s not that these cells aren’t willing to do the job;
it’s just that they can’t detect the leukemia cells. Using the altered HIV, Dr.
June is adding a gene to the T-cells to be able to detect CD-19 markers of the
leukemia cells.
The
reprogramming step takes full advantage of one of HIV’s signature characteristics:
insert new DNA into the host genome. HIV specifically targets helper T (CD4+)
cells. In a normal infection, HIV will integrate its viral DNA into the genome,
which would result in new HIV virions made and death of the host cell. In Dr.
June’s treatment, they have “disabled” the virus, leaving only its ability to
get into helper T-cells and integrate new genes (not viral genes). Once the
T-cells have been successfully reprogrammed, they are re-administered to the
patient where, as Dr. June puts it, “they become serial killers” against the
cancerous cells. And because T-cells are part of the “memory” immune response,
these cells will lay dormant unless the cancer cells come back, where they will
once again become killers.
Although this treatment is currently
only used on patients with ALL, non-Hodgkins lymphoma, and chronic lymphocytic
leukemia, trials will begin this summer on patients with pancreatic cancer. It’s
not implausible to think that in the near future, many cancers can be
effectively cured by T-cells that have been reprogrammed by HIV. So cancer
patients, just stay positive!
References:
"Survival Rate and Prognosis for Acute Lymphoblastic
Leukemia." Acute Lymphoblastic Leukemia: Survival Rate and
Prognosis. N.p., n.d. Web. 14 Jan. 2015.
"T Cell Therapy (CTL019)." The Children's
Hospital of Philadelphia. N.p., n.d. Web. 14 Jan. 2015.
"WHAT IS CANCER." ? N.p., n.d.
Web. 14 Jan. 2015.
"Woods Cross Man's Cancer in Remission Thanks to HIV |
KSL.com." Woods Cross Man's Cancer in Remission Thanks to HIV |
KSL.com. N.p., n.d. Web. 14 Jan. 2015.
You’Ve Been Told You Have Cancer. You’Ve Looked At Your
Treatment Options, And You And, Your Doctor Have Agreed That Chemotherapy Is
Your Best Choice. Now You Have Questions, About Chemotherapy Treatment., and
The American Cancer Society Knows That You May Have Concerns About
Chemotherapy,. A Guide to Chemotherapy (n.d.): n. pag. Web.
Images:
http://31.media.tumblr.com/tumblr_m6idxv05ph1r4gei2o5_400.gif
http://www.quickmeme.com/meme/3pjp9a
http://www.genetherapynet.com/viral-vector/retroviruses.html
