New Methods in Targeting Pancreatic Cancer

Transcript

00:00 --> 00:02Funding for Yale Cancer Answers is
00:02 --> 00:04provided by Smilo Cancer Hospital.
00:06 --> 00:08Welcome to Yale Cancer Answers
00:08 --> 00:10with Doctor Aneesh Chagpar.
00:10 --> 00:12Yale Cancer Answers features the
00:12 --> 00:14latest information on cancer care
00:14 --> 00:15by welcoming oncologists and
00:15 --> 00:17specialists who are on the forefront
00:17 --> 00:19of the battle to fight cancer.
00:19 --> 00:21This week it's a conversation
00:21 --> 00:23about research into new methods
00:23 --> 00:25for targeting pancreatic cancer
00:25 --> 00:26with Doctor Moi Bhattacharya.
00:26 --> 00:28Doctor Bhattacharya is an assistant
00:28 --> 00:30professor of pharmacology at
00:30 --> 00:32the Yale School of Medicine,
00:32 --> 00:34where Doctor Chagpar is a
00:34 --> 00:35professor of surgical oncology.
00:36 --> 00:38So wait, maybe we can start off by
00:38 --> 00:40you telling us a little bit more
00:40 --> 00:42about yourself and what it is you do.
00:42 --> 00:47I am a biophysicist by training.
00:47 --> 00:51My lab is very multidisciplinary.
00:51 --> 00:54We study membrane localized cell
00:54 --> 00:57signaling from different perspectives
00:57 --> 00:59starting from pancreatic cancer which
00:59 --> 01:02is what we are focused on today,
01:02 --> 01:05but also from the direction of
01:05 --> 01:08psychiatric disorders and pain perception.
01:08 --> 01:11And we bring in various techniques
01:11 --> 01:13to answer the question.
01:13 --> 01:14We are very question centric,
01:14 --> 01:17problem centric where the biology
01:17 --> 01:20is decided 1st and then we just
01:20 --> 01:22bring in various methodologies
01:22 --> 01:25that are available or we make
01:25 --> 01:27new technologies to answer the
01:27 --> 01:30questions that are important to us.
01:30 --> 01:34So we are at the Sterling Hall of
01:34 --> 01:37Medicine and I'm a relatively new lab.
01:37 --> 01:39I have been at Yale only for about 3
01:39 --> 01:421/2 years and it's been great so far.
01:43 --> 01:46OK. So we, you know, kind of set
01:46 --> 01:48the stage for us in terms of how
01:48 --> 01:50you got interested in pancreatic
01:50 --> 01:52cancer and what exactly are the
01:52 --> 01:53questions that you're studying,
01:54 --> 01:58right. So you know I,
01:58 --> 02:02when I was looking into as I said
02:02 --> 02:03I'm a biophysicist by training,
02:03 --> 02:08but we have a really interesting,
02:08 --> 02:10you know, we love approaching
02:10 --> 02:12interesting biological problems,
02:12 --> 02:14outstanding biological problems
02:14 --> 02:17with our biophysical technologies.
02:17 --> 02:19And when I was looking into
02:19 --> 02:21the literature it seemed like,
02:21 --> 02:24I mean there are pancreatic cancer is
02:24 --> 02:28probably one with the lowest five year
02:28 --> 02:31survival rates and there are so many
02:31 --> 02:33outstanding questions that still exist.
02:33 --> 02:37I think one of the biggest one is we know
02:37 --> 02:41that this particular gene called Ras,
02:41 --> 02:44specifically K Ras for pancreatic cancer,
02:44 --> 02:47that is a well known marker
02:47 --> 02:48for pancreatic cancer.
02:48 --> 02:51It's mutated in pancreatic cancer more
02:51 --> 02:55than 95% of all screened patients.
02:55 --> 02:59So immediately one would think that
02:59 --> 03:01this would be a fantastic target to
03:01 --> 03:04you know inhibit or pharmacologically
03:04 --> 03:06target to treat pancreatic cancer
03:06 --> 03:09and this knowledge has been out
03:09 --> 03:12there for last 20 plus years.
03:12 --> 03:12However,
03:12 --> 03:16in pancreatic cancer there is no
03:16 --> 03:19chaos targeted therapies that exist
03:19 --> 03:23still And the key reason for that
03:23 --> 03:25is chaos has been traditionally
03:25 --> 03:29a very difficult to drug target.
03:29 --> 03:32And we were really interested in
03:32 --> 03:34this because this is here is a
03:34 --> 03:37protein or a gene that is immediately
03:37 --> 03:38correlated statistically with
03:38 --> 03:40a particular form of cancer,
03:40 --> 03:41pancreatic cancer.
03:41 --> 03:45Why are we not targeting that protein?
03:45 --> 03:47And then when we delved
03:47 --> 03:48deeper into the literature,
03:48 --> 03:50it became obvious to us that
03:50 --> 03:52why it was not done.
03:52 --> 03:55And we wanted to study this protein
03:55 --> 03:57from a molecular standpoint to see
03:57 --> 04:00if we can expose some new you know
04:00 --> 04:03a pain points for the protein,
04:03 --> 04:05some new Achilles heel in the protein
04:05 --> 04:07that can be pharmacl logically targeted.
04:07 --> 04:11And that is what kind of motivated
04:11 --> 04:13our looking into this particular
04:13 --> 04:15protein with our biophysical,
04:15 --> 04:17newly developed biophysical techniques.
04:18 --> 04:20So I mean it's it makes sense that
04:20 --> 04:23if KRAS is mutated in the vast
04:23 --> 04:25majority of pancreatic cancers that
04:25 --> 04:28it would be an obvious target.
04:28 --> 04:33Tell us more about why exactly previous
04:33 --> 04:35labs found it so difficult to come
04:35 --> 04:38up with a Ras targeted protein and
04:38 --> 04:40and what the techniques that you
04:40 --> 04:43have are that made you feel more
04:43 --> 04:45confident that you could approach
04:45 --> 04:49this task that others failed at.
04:50 --> 04:52Right. So I'll answer the first question
04:52 --> 04:55like why has it been so difficult?
04:55 --> 04:59First, Ras is a very small protein.
05:00 --> 05:01It doesn't have a lot of
05:01 --> 05:03pockets where drugs can bind.
05:03 --> 05:05It's a very shallow protein,
05:05 --> 05:08small shallow protein with not
05:08 --> 05:11very many deep pockets which are
05:11 --> 05:14traditionally targeted by drugs.
05:14 --> 05:19At the same time, Ras actually binds GTP.
05:19 --> 05:22The nucleotide and it's affinity
05:22 --> 05:25for GTP is also very tight.
05:25 --> 05:28It is very difficult to make a
05:28 --> 05:30GTP competitive inhibitor for Ras.
05:30 --> 05:33I think as a function of that,
05:33 --> 05:36because of these two main reasons,
05:36 --> 05:39Ras has remained difficult to drug for long.
05:39 --> 05:41Recently over the last five years,
05:41 --> 05:44there had been new drugs against
05:44 --> 05:47Ras which take the advantage of
05:47 --> 05:49certain Ras mutants in cancer
05:49 --> 05:52which can be covalently bound to
05:52 --> 05:55drugs like the mutation at G12.
05:55 --> 05:58The possession glycine 12 into a
05:58 --> 06:00cysteine where the cysteine could be
06:00 --> 06:03used as a covalent kind of prong to
06:03 --> 06:05bring in a drug and bind it because
06:05 --> 06:08there is no deep pockets to bind you
06:08 --> 06:11know otherwise bind drug in Ross.
06:11 --> 06:11However,
06:11 --> 06:15in pancreatic cancer the G12C
06:15 --> 06:17mutation is not that common.
06:17 --> 06:19The most common mutations
06:19 --> 06:22are G12VG12D which are not,
06:22 --> 06:25you know capable of being targeted
06:25 --> 06:27by this drug because they cannot
06:27 --> 06:29be covalently modified.
06:29 --> 06:32So there lies these open,
06:32 --> 06:36you know, area a gap where OK,
06:36 --> 06:38it can be used for certain
06:38 --> 06:40cancers showing the G12C mutation.
06:40 --> 06:42But what about pancreatic cancer
06:42 --> 06:44where that mutation doesn't appear
06:44 --> 06:46and the ones that appear cannot
06:46 --> 06:48be targeted by covalent drugs.
06:48 --> 06:50So what we did,
06:50 --> 06:53we asked a different question.
06:53 --> 06:54We asked that, OK,
06:54 --> 06:56Ras doesn't have deep pockets,
06:56 --> 06:59but can Ras actually form an
06:59 --> 07:01oligomer or a dimer?
07:01 --> 07:04And does that dimer actually have or
07:04 --> 07:06dimerization or formation basically
07:06 --> 07:10having multiple rust subunits come together,
07:10 --> 07:13Does that have an impact on
07:13 --> 07:16downstream signaling in physiological
07:16 --> 07:17and oncogenic conditions?
07:17 --> 07:21Because if that connection is established,
07:21 --> 07:25then that oligomeric interface now becomes
07:25 --> 07:28a target for pharmacological interventions.
07:28 --> 07:32So with that kind of motivating
07:32 --> 07:33factor as our guide,
07:33 --> 07:36we asked the question that can we
07:36 --> 07:39actually look at oligomeric status of Ras?
07:39 --> 07:42But there lies a problem because
07:42 --> 07:44looking at membrane protein,
07:44 --> 07:47oligomeric organization has long remained
07:47 --> 07:50A challenging problem in biophysics.
07:50 --> 07:53It is a solved problem for soluble proteins,
07:53 --> 07:55but with membrane proteins it is
07:55 --> 07:57challenging primarily because
07:57 --> 07:58of three reasons.
07:58 --> 08:01The first reason is it is difficult to
08:01 --> 08:03distinguish oligomeric organization
08:03 --> 08:06from subunits that are just hanging
08:06 --> 08:08around spatially proximal on the membrane.
08:08 --> 08:10So we don't know that is are the
08:10 --> 08:12two subunits of rust coming together
08:12 --> 08:14to form a dimer on the membrane or
08:14 --> 08:17the two subunits are just spatially
08:17 --> 08:19proximal because of the technologies
08:19 --> 08:22that were available to us till date.
08:22 --> 08:24So my lab first developed a new
08:24 --> 08:26technology to look,
08:26 --> 08:28a generalized technology to look
08:28 --> 08:31at membrane protein oligomeric organization.
08:31 --> 08:34And then we applied that technology
08:34 --> 08:37after having validated it to Ras
08:37 --> 08:39to ask the question that can this
08:39 --> 08:40hallmark
08:40 --> 08:42oncogene form dimers or higher
08:42 --> 08:45order oligomers on membranes and
08:45 --> 08:48does oncogenic mutations alter this
08:48 --> 08:50distribution because that will
08:50 --> 08:52now expose an Achilles heel for
08:52 --> 08:55Ras and we did this for K Ras in
08:55 --> 08:57the context of pancreatic cancer.
08:59 --> 09:02And so, you know,
09:02 --> 09:05help me to understand, you know,
09:05 --> 09:08how exactly you take advantage of
09:08 --> 09:13this dimerization or oligomerization.
09:13 --> 09:16Does this happen in nature?
09:16 --> 09:19Does this happen in cancers?
09:19 --> 09:22Is this something that's inducible?
09:22 --> 09:24How does that work exactly?
09:24 --> 09:26That's a great question actually.
09:26 --> 09:32So what we realized is chaos in its
09:32 --> 09:35wild type in its native state exists
09:35 --> 09:37as a monomer dimer equilibrium.
09:37 --> 09:41However, upon introduction of well
09:41 --> 09:43known prominent oncogenic mutations,
09:43 --> 09:47we saw that the population of dimers went up
09:47 --> 09:51and the population of monomers went down.
09:51 --> 09:54And the hypothesis here is with
09:54 --> 09:56increased dimerization of K Ras,
09:56 --> 10:00it may be now able to hyperactivate
10:00 --> 10:02the downstream MAP K Ras,
10:02 --> 10:05MAP K signaling pathway that has
10:06 --> 10:08a huge role in cell proliferation
10:08 --> 10:10and differentiation and that
10:10 --> 10:13could be you know connected to the
10:13 --> 10:15uncontrolled cell growth in cancer.
10:15 --> 10:19So the connection is that increased
10:19 --> 10:22dimers of chaos in the oncogenic
10:22 --> 10:26mutation case actually may now trigger
10:26 --> 10:28increased MAP case signaling which
10:28 --> 10:31leads to uncontrolled cell growth.
10:31 --> 10:34So we have shown that there is
10:34 --> 10:36increased dimerization in cancer.
10:36 --> 10:38Our next goal is to connect this with
10:38 --> 10:40the downstream signaling aspect.
10:40 --> 10:43And then we can say that, OK,
10:43 --> 10:45great, increase dimer,
10:45 --> 10:47increase signaling in cancer,
10:47 --> 10:49if we break the dimer by a small
10:49 --> 10:51molecule or by a mono body,
10:51 --> 10:54a nano body that will reverted back
10:54 --> 10:56to its wild type or native status
10:56 --> 11:00and that may be able to stop the
11:00 --> 11:02hyperactivated downstream signaling.
11:04 --> 11:06And so tell us more about
11:06 --> 11:09how that that works. I mean,
11:09 --> 11:12because it sounds like you've already
11:12 --> 11:15established that when this equilibrium,
11:15 --> 11:19this monomer dimer equilibrium shifts
11:19 --> 11:22towards dimerization that you have more
11:22 --> 11:24of this downstream signaling, right?
11:24 --> 11:30That is more like the oncogenic state and so.
11:30 --> 11:32So I guess there's a couple of questions.
11:32 --> 11:36One, is it possible in fact to break
11:36 --> 11:40that and to shift these cells to
11:40 --> 11:43a more monomeric state And two,
11:43 --> 11:48does the monomeric state have have less
11:48 --> 11:51downstream signaling that is less oncogenic?
11:51 --> 11:55So tell us more about how you you
11:55 --> 11:57can kind of revert these dimers
11:57 --> 12:01back to a monomeric state, right.
12:01 --> 12:02So
12:02 --> 12:04with our new technology,
12:04 --> 12:07the native nano bleach where we can look
12:07 --> 12:10into redistribution of oligomeric assemblies,
12:10 --> 12:15we can now start screening for small
12:15 --> 12:18molecules or set antibody or a mono
12:18 --> 12:20body that will revert the states.
12:20 --> 12:23So this is not published in unpublished data.
12:23 --> 12:27We have some early kind of indications
12:27 --> 12:31that there is a mono body which when we
12:31 --> 12:35screened using our technology can actually
12:35 --> 12:38revert back the increased dimeric state
12:38 --> 12:41of chaos back to its wild type levels.
12:41 --> 12:44So we have evidence that that mono body
12:44 --> 12:47exists and that existed in the literature,
12:47 --> 12:51but there was not a good understanding
12:51 --> 12:54of the mechanism of how it was
12:54 --> 12:56able to kill oncogenic signaling.
12:56 --> 12:59And now we have provided A
12:59 --> 13:01mechanistic explanation that OK,
13:01 --> 13:04that is happening by actually
13:04 --> 13:06reducing the dimeric population.
13:06 --> 13:09So that is our first indication
13:09 --> 13:12that it can be actually broken.
13:12 --> 13:15It can be reverted back to the OR you know
13:15 --> 13:18to the wild type status of monomer dimer.
13:18 --> 13:20The increased dimer can be
13:20 --> 13:23actually pushed back and that is
13:23 --> 13:25connected to decreased signaling.
13:25 --> 13:27So that is a very exciting Ave.
13:27 --> 13:30that we are exploring in our
13:30 --> 13:31next set of studies.
13:32 --> 13:34Fantastic. Well, we need to take a
13:34 --> 13:37short break here for a medical minute.
13:37 --> 13:39Please stay tuned to learn more
13:39 --> 13:41about new methods in targeting
13:41 --> 13:43pancreatic cancer with my guest,
13:43 --> 13:45Doctor Moi Bhattacharya.
13:46 --> 13:48Funding for Yale Cancer Answers
13:48 --> 13:50comes from Smilo Cancer Hospital,
13:50 --> 13:52where their Cancer Genetics and
13:52 --> 13:53Prevention program includes
13:53 --> 13:55a Colon Cancer Genetics and
13:55 --> 13:57Prevention Program that provides
13:57 --> 13:58comprehensive risk assessment,
13:58 --> 14:00education and screening
14:02 --> 14:02milocancerhospital.org
14:04 --> 14:06Breast cancer is one of the
14:06 --> 14:08most common cancers in women.
14:08 --> 14:09In Connecticut alone,
14:09 --> 14:11approximately 3500 women will be
14:11 --> 14:14diagnosed with breast cancer this year,
14:14 --> 14:15but there is hope thanks
14:15 --> 14:16to earlier detection,
14:16 --> 14:17non invasive treatments,
14:17 --> 14:20and the development of novel therapies.
14:20 --> 14:21To fight breast cancer,
14:21 --> 14:24women should schedule a baseline mammogram
14:24 --> 14:27beginning at age 40 or earlier if they have
14:27 --> 14:29risk factors associated with the disease.
14:29 --> 14:31With screening, early detection,
14:31 --> 14:32and a healthy lifestyle,
14:32 --> 14:35breast cancer can be defeated.
14:35 --> 14:36Clinical trials are currently
14:36 --> 14:38underway at federally designated
14:38 --> 14:40comprehensive cancer centers,
14:40 --> 14:41such as Yale Cancer Center
14:41 --> 14:43and its Mylo Cancer Hospital,
14:43 --> 14:45to make innovative new treatments
14:45 --> 14:47available to patients.
14:47 --> 14:48Digital breast tomosynthesis,
14:48 --> 14:51or 3D mammography is also transforming
14:51 --> 14:54breast cancer screening by significantly
14:54 --> 14:56reducing unnecessary procedures
14:56 --> 14:58while picking up more cancers.
14:58 --> 15:00More information is available
15:00 --> 15:01at yalecancercenter.org.
15:01 --> 15:04You're listening to Connecticut Public Radio.
15:05 --> 15:07Welcome back to Yale Cancer Answers.
15:07 --> 15:09This is Doctor Aneesh Jagpar,
15:09 --> 15:11and I'm joined tonight by my guest,
15:11 --> 15:13Doctor Moi Bhattacharya.
15:13 --> 15:15We're talking about new methods
15:15 --> 15:17in targeting pancreatic cancer.
15:17 --> 15:19And right before the break,
15:19 --> 15:21Moi was telling us about some work
15:21 --> 15:23that's been going on in her lab
15:23 --> 15:25that looks at a new technology.
15:25 --> 15:28Basically, the idea is that
15:28 --> 15:29for most pancreatic cancers,
15:29 --> 15:32there's a mutation in K Ras.
15:32 --> 15:36And what she was able to discover was that
15:36 --> 15:39these K Ras molecules sometimes dimerize.
15:39 --> 15:41There's this, there's this balance
15:41 --> 15:44between monomers and dimers.
15:44 --> 15:47And when K Ras is in that dimeric state,
15:47 --> 15:51that's when the oncogenic signaling happens.
15:51 --> 15:54Well, it turns out that although we've
15:54 --> 15:57known about K Ras for a long time,
15:57 --> 15:582 decades or so,
15:58 --> 16:00nobody's ever been really able
16:00 --> 16:02to target it effectively.
16:02 --> 16:04Well, now there's new technology
16:04 --> 16:08that might end up pushing K Ras to be
16:08 --> 16:11more in its Monomeric state and have
16:11 --> 16:14less of that oncogenic signaling and
16:14 --> 16:18potentially that can be really exciting.
16:18 --> 16:20So Moya, I want to pick up the
16:20 --> 16:21discussion where we left it.
16:21 --> 16:25So when you use this new technology,
16:25 --> 16:28I think you called it nano bleach, right?
16:28 --> 16:30Native nano bleach,
16:30 --> 16:31native nano bleach.
16:31 --> 16:35It's a first of all interesting name.
16:35 --> 16:37I guess the first question is how
16:37 --> 16:39did you come up with that name?
16:39 --> 16:42But the other question is and
16:42 --> 16:44maybe tied to this,
16:44 --> 16:47can you talk a little bit about
16:47 --> 16:50how exactly this is delivered
16:50 --> 16:52and what the side effects are,
16:53 --> 16:57right. So the native nano bleach
16:57 --> 17:00technology is basically a way to look
17:00 --> 17:03into the changes in the oligomeric
17:03 --> 17:05organization of membrane proteins in
17:05 --> 17:09the context of their native membranes.
17:09 --> 17:13So the way we develop this technology
17:13 --> 17:15is it has remained A challenging problem
17:15 --> 17:17to look at oligomeric organization
17:17 --> 17:19of membrane proteins due to many,
17:20 --> 17:21many different reasons.
17:21 --> 17:25I think the most prominent reason of those
17:25 --> 17:28is the fact that the membrane proteins
17:28 --> 17:32sit in the in a pool of native lipids,
17:32 --> 17:35so their buffering media
17:35 --> 17:37is comprised of lipids.
17:37 --> 17:41Now most preparations of looking
17:41 --> 17:43biophysically into membrane proteins
17:43 --> 17:46erase this native membrane context.
17:46 --> 17:49Their native milieu is gone,
17:49 --> 17:52and more often than not,
17:52 --> 17:55this native locale of the membrane
17:55 --> 17:57proteins is really important in
17:57 --> 17:59templating their organization,
18:00 --> 18:02their function, the downstream signaling,
18:02 --> 18:04and so on.
18:04 --> 18:06But there exists really no
18:06 --> 18:08technology to look at, you know,
18:08 --> 18:09membrane proteins without
18:09 --> 18:10the use of detergents,
18:10 --> 18:13which is what is commonly used that
18:13 --> 18:16strips off this native membrane context.
18:16 --> 18:17That's the first problem.
18:17 --> 18:20The second problem is often when we
18:20 --> 18:22are looking at membrane proteins
18:22 --> 18:25we are using light microscopy.
18:25 --> 18:27And using light microscopy,
18:27 --> 18:31it is very difficult to distinguish if
18:31 --> 18:34two subunits of the protein are, say,
18:34 --> 18:37at 100 nanometer apart from each other,
18:37 --> 18:40or 10 nanometer apart or five nanometer
18:40 --> 18:43apart when they're truly forming a complex.
18:43 --> 18:45And this is because something that is
18:45 --> 18:47called the diffraction limit of light,
18:47 --> 18:51which does not allow us to distinguish
18:51 --> 18:542 or more particles as you know
18:54 --> 18:56individual ones when they're closer
18:56 --> 18:59than 200 nanometer of each other.
18:59 --> 19:01So that is the second challenge.
19:01 --> 19:03So we didn't have a technology to
19:03 --> 19:05look into organization of membrane
19:05 --> 19:07proteins using light microscopy.
19:07 --> 19:08And finally,
19:08 --> 19:11any technique that looks into this
19:11 --> 19:13question has to work with proteins
19:13 --> 19:16at a wide range of expression levels
19:16 --> 19:19including proteins as they are produced
19:19 --> 19:21in the cell without over expressing
19:21 --> 19:24them without with minimal manipulation
19:24 --> 19:27basically to the native environment.
19:27 --> 19:30So we realized that we have now we
19:30 --> 19:34used up an antipathic copolymer to
19:34 --> 19:38basically cut out membrane protein
19:38 --> 19:41from you know circular patches of
19:41 --> 19:43the native membrane environment.
19:43 --> 19:45Think of it as cutting out cookies
19:45 --> 19:48out of native membrane dough.
19:48 --> 19:49So you have the membrane.
19:49 --> 19:51You're cutting out this cookies.
19:51 --> 19:52Each cookie,
19:52 --> 19:54which is about 10 nanometer in diameter,
19:54 --> 19:57contains all the subunits of a
19:57 --> 19:59membrane protein of interest.
19:59 --> 20:02Then you count how many subunits
20:02 --> 20:04are of the membrane protein of
20:04 --> 20:07your interest is present in that
20:07 --> 20:1010 nanometer cookie. So now.
20:10 --> 20:13We have overcome the problem of the
20:13 --> 20:15diffraction limit of light because
20:15 --> 20:17we are imposing A lateral spatial
20:17 --> 20:20resolution of 10 nanometer physically
20:20 --> 20:23using our sample because we are
20:23 --> 20:25counting the number of subunits
20:25 --> 20:28within each native nano disk which
20:28 --> 20:30is what we call these cookies.
20:30 --> 20:34So that is the reason why we named
20:34 --> 20:36our technology native nano bleach,
20:36 --> 20:39because it is native nano disk
20:39 --> 20:41photo bleaching technology where we
20:41 --> 20:44are counting using photo bleaching
20:44 --> 20:45analysis the number of
20:45 --> 20:47subunits of a protein that
20:47 --> 20:49is within each nano disk.
20:49 --> 20:52Now from this point on,
20:52 --> 20:54we have now a generalized technique
20:54 --> 20:57that actually can look into oligomeric
20:57 --> 21:00organization of any membrane protein,
21:00 --> 21:03not just KRAS, but any,
21:03 --> 21:05any of your favorite membrane protein.
21:05 --> 21:08And that is how we developed a new
21:08 --> 21:10technology that made asking this
21:10 --> 21:13question that does actually you know
21:13 --> 21:16Kairos form dimers or higher order
21:16 --> 21:18oligomers and what happens upon
21:18 --> 21:20oncogenic mutations even possible
21:20 --> 21:23because this question was intractable
21:23 --> 21:25without the advent of this technology.
21:27 --> 21:29And so this is great.
21:29 --> 21:31I mean it sounds really exciting that
21:31 --> 21:34you know you found a way to look at
21:34 --> 21:36these membrane proteins and study them.
21:36 --> 21:40You've found a way to get the
21:40 --> 21:43dimers to separate into monomers.
21:43 --> 21:46So you know shifting that balance
21:46 --> 21:48and and you've demonstrated at least
21:48 --> 21:50in early unpublished work that
21:50 --> 21:52there is in the monomeric state
21:52 --> 21:54which you're able to shift these
21:54 --> 21:57these molecules cules too there's
21:57 --> 22:00less of that downstream signaling.
22:00 --> 22:03So then the question becomes
22:03 --> 22:05that's great in the lab,
22:05 --> 22:09how do you get that into people and
22:09 --> 22:11what are the side effects of this
22:12 --> 22:15right. So you know,
22:15 --> 22:18we are approaching this question
22:18 --> 22:21from a molecular framework,
22:21 --> 22:22you know perspective.
22:22 --> 22:26And I think the next steps to moving
22:26 --> 22:29towards more translational research
22:29 --> 22:33with this would be to actually scream
22:33 --> 22:37now that we have established that
22:37 --> 22:39Dimer's actually may be connected
22:39 --> 22:42to the hyperactive signaling in
22:42 --> 22:44Ras mutant cancers and it can be,
22:44 --> 22:48you know when that is reverted back that
22:48 --> 22:50hyperactive signaling is ameliorated 1.
22:50 --> 22:53Can think of using this as a
22:53 --> 22:55screening platform for say small
22:55 --> 22:57molecules that will now break the
22:57 --> 23:00Ras dimers or other form of drugs
23:00 --> 23:02like antibodies or nanobodies
23:02 --> 23:04that will break this Ras dimer.
23:04 --> 23:08So that'll I think be the step one to
23:08 --> 23:10identify new new molecular competence
23:10 --> 23:13that's going to now break this dimer.
23:13 --> 23:15Once we have identified that,
23:15 --> 23:16then we go to Step 2.
23:16 --> 23:18Are these molecular components
23:18 --> 23:21that are capable of breaking the
23:21 --> 23:24dimers actually work in the setup
23:24 --> 23:26of animal models And then of
23:26 --> 23:29course move that on to trials and
23:29 --> 23:32patients and so on and so forth.
23:32 --> 23:36I think the this is going to be one approach.
23:36 --> 23:39The other approach is to go back
23:39 --> 23:41and look into the literature and see
23:41 --> 23:44that if there were other already
23:44 --> 23:47existing monobodies or antibodies
23:47 --> 23:50that were shown to reduce hyperactive
23:50 --> 23:52signaling in Ras mutant cancer
23:52 --> 23:55and can be actually explain their
23:55 --> 23:58function using the Ras dimerization.
23:58 --> 24:00You know decrease in in the
24:00 --> 24:02in the cancer setup.
24:02 --> 24:04So I think the first step would
24:04 --> 24:05be discovery of these molecular
24:05 --> 24:08components that can break the dimers
24:08 --> 24:10and decrease signaling and then
24:10 --> 24:13the second component will be moving
24:13 --> 24:16this along to the next steps more
24:16 --> 24:18translational steps side effect wise.
24:18 --> 24:21The one thing I can think of is you
24:21 --> 24:24know Ras as we found K Ras exists as
24:24 --> 24:27a monomer and dimer to begin with.
24:27 --> 24:30It has an equilibrium roughly 5050,
24:30 --> 24:32sixty, forty I would say.
24:32 --> 24:35And then only in the oncogenic setup
24:35 --> 24:40the dimers go up up to like 70% and
24:40 --> 24:43the monomers go down to say 30%.
24:43 --> 24:47We have to revert the dimers back
24:47 --> 24:49to wild type levels,
24:49 --> 24:51but we don't want to break maybe
24:51 --> 24:53the entirety of the dimers because
24:53 --> 24:56we know that in the native state it
24:56 --> 24:58already exists as a monomer dimer
24:58 --> 25:00and breaking the entire dimeric
25:00 --> 25:04population may actually be detrimental.
25:04 --> 25:06So it's like, you know, an Abacus scale.
25:06 --> 25:08We are trying to move it,
25:08 --> 25:11tune it to the perfect level where the
25:11 --> 25:13dimers are brought back to the native levels,
25:13 --> 25:16but not like completely ablated because
25:16 --> 25:20I can foresee that that might actually
25:20 --> 25:23have some side effects like some,
25:23 --> 25:24you know,
25:24 --> 25:26negative effects because Ross signaling is
25:26 --> 25:29absolutely critical for our cell growth,
25:29 --> 25:30maintenance and proliferation
25:30 --> 25:33and we have to just recalibrate
25:33 --> 25:35things back to the native levels.
25:37 --> 25:42So can you, I mean it sounds like the,
25:42 --> 25:45you know we are at the beginning stages
25:45 --> 25:48of what might be a really exciting Rd.
25:48 --> 25:50Can you talk a little bit about
25:50 --> 25:52how this technology might be
25:52 --> 25:54used in other cancers as well,
25:54 --> 25:55I mean Ras doesn't exist
25:55 --> 25:57just in pancreatic cancer,
25:57 --> 25:59absolutely, that's a great question
25:59 --> 26:02because we are actually starting to study.
26:02 --> 26:07So Ras actually comes in as like four
26:07 --> 26:09different isoforms and splice variants.
26:09 --> 26:10There's K Ras,
26:10 --> 26:134A and 4B which are splice variants,
26:13 --> 26:17and then there is H Ras and N Ras.
26:17 --> 26:19Now it was shown very,
26:19 --> 26:22very nicely over the last, you know,
26:22 --> 26:25a beautiful work over the last three
26:25 --> 26:28decades that each of the Ras isoform
26:28 --> 26:32seems to have a prominent role in
26:32 --> 26:35a given type of cancer or a given,
26:35 --> 26:37you know, set of cancers.
26:37 --> 26:39For example, Keras is really
26:39 --> 26:41prominent in pancreatic cancer,
26:41 --> 26:45lung cancer, whereas Enras mutations
26:45 --> 26:48really prominent in melanomas.
26:48 --> 26:51So what is this?
26:51 --> 26:52You know,
26:52 --> 26:54what is the connection between different
26:54 --> 26:57Ras isoforms and their connection
26:57 --> 26:59to a particular type of cancer?
26:59 --> 27:01How are these isoforms different?
27:01 --> 27:03And that's actually an important
27:03 --> 27:06question because if you look at sequence
27:06 --> 27:08identity between the Ras isoforms,
27:08 --> 27:10which is often what you know
27:10 --> 27:13biologists look at to see if the
27:13 --> 27:14two proteins are very similar,
27:14 --> 27:16different or if they're very
27:16 --> 27:17different from each other,
27:18 --> 27:21you will see that the Ras isoforms are
27:21 --> 27:22remarkably identical to each other.
27:22 --> 27:24They actually have about 90%
27:24 --> 27:27sequence identity with each other.
27:27 --> 27:30Despite that, despite being so you know,
27:30 --> 27:32similar in sequence,
27:32 --> 27:35they are actually playing out.
27:35 --> 27:38They seem to be having different,
27:38 --> 27:39you know, prominence,
27:39 --> 27:41different levels of prominence,
27:41 --> 27:44prominence in different types of cancers,
27:44 --> 27:46different oncogenic mutations
27:46 --> 27:49are playing different roles in
27:49 --> 27:51different types of cancers.
27:51 --> 27:55So there is I think a lot of mystery
27:55 --> 27:57that is still unsolved that where
27:57 --> 28:00is all this fidelity coming from?
28:00 --> 28:02How are these isoforms,
28:02 --> 28:04which are apparently very similar,
28:04 --> 28:05playing, you know,
28:05 --> 28:07very distinct roles in different
28:07 --> 28:08types of cancers.
28:08 --> 28:10So those are the kind of questions,
28:10 --> 28:12like basic science questions,
28:12 --> 28:15We are trying to, you know,
28:15 --> 28:17approach next with our studies.
28:17 --> 28:19Doctor Moi Bhattacharya is an
28:19 --> 28:21assistant professor of pharmacology
28:21 --> 28:23at the Yale School of Medicine.
28:23 --> 28:25If you have questions,
28:25 --> 28:27the address is canceranswers@yale.edu,
28:27 --> 28:30and past editions of the program
28:30 --> 28:32are available in audio and written
28:32 --> 28:33form at yalecancercenter.org.
28:33 --> 28:36We hope you'll join us next week to
28:36 --> 28:38learn more about the fight against
28:38 --> 28:39cancer here on Connecticut Public Radio.
28:39 --> 28:41Funding for Yale Cancer Answers is
28:41 --> 28:43provided by Smilo Cancer Hospital.

Download Audio Download Transcript

Information

New Methods in Targeting Pancreatic Cancer with guest Moi Bhattacharya March 17, 2024