Viewing a single comment thread. View all comments

JackD4wkins t1_jdw120z wrote

If we can genetically change immune cells to fight cancer, why not simply change cancer cells to die instead? CINDELA got it right. Cut out the middle man

11

OneDayCloserToDeath t1_jdwk23m wrote

They way we do it now is as follows:

  1. hospital sends blood of the cancer patient to us.
  2. we filter out all the cells other than the killer T cells
  3. we inject a virus that contains the genetic material that fights the cancer. The virus infects the killer T-cells and inserts its own genetic material into the T-cells.
  4. we incubate and grow the T-cells a little over a week until there are enough to meet the required dose.
  5. we wash out the viruses and cell food juices, freeze the cells, and send them back to the hospital.
  6. doctor injects the cells back into the patient and they usually become cancer free within two weeks.

I don't see how you would change all the cancer cells in this way. It's more complicated people might think.

27

JackD4wkins t1_jdwpuwf wrote

Just inject a virus into the cancer directly that contains genetic material designed to disrupt cancer DNA.

Immunotherapy does not work for most people, or even most cancers today...

−6

OneDayCloserToDeath t1_jdwtzoj wrote

And how do you stop the virus from infecting healthy cells and causing more harm than good?

12

Toranagas1 t1_jebqx8n wrote

The technology they is referring to uses whole genome sequencing to identify InDel mutations in tumor cells then uses Cas9/gRNA specifc for those InDel sequences to induce double stranded DNA breaks, resulting in cell death. Since those sequences don't in theory exist elsewhere in the patient, it may be safe. Looks like a lot of different gRNAs are needed though for good efficacy.

They use lentivirus and AAVs to deliver them in vivo.

The in vivo efficacy data is...fine. The big thing here is the personalized medicine aspect.

PMID: 35217600

1

JackD4wkins t1_jdxda7b wrote

Because you coded the the virus enzyme to specifically target cancer DNA and not healthy DNA. Even if the virus infects a healthy cell, it will have no effect

−2

OneDayCloserToDeath t1_jdxhmrz wrote

Is this done? Do you have any information on it working?

3

JackD4wkins t1_jdxjblw wrote

They're working on it in South Korea. Its called the CINDELA program. Not sure what the status is

0

ecnecn t1_jdzehcr wrote

>CINDELA program

You mean Cancer-Specific InDel Attacker (Cindela) ? I didnt know they use reprogrammed viruses...

1

Phoenix5869 t1_jdw9452 wrote

That‘s called programmed apoptosis and we’ve been trying to figure it out for decades

13

JackD4wkins t1_jdwhfop wrote

With crispr you can just attack the cancer DNA itself and shred it. No fancy reprogramming needed

−5

r0b0c0p316 t1_jdwq1gi wrote

We have lots of things that will destroy cancerous cells. The main problem is making sure they specifically target the cancer and not any normal tissue.

14

JackD4wkins t1_jdwq9d8 wrote

Doesn't seem to be a concern when we're using chemo and radiation as the current standard of care lol. Today, ~10% of all new cancers are linked to prior cancer treatments

−1

r0b0c0p316 t1_jdwrms7 wrote

Many chemotherapy drugs are designed to inhibit or kill rapidly dividing cells which allow us to hit cancers with some specificity but other cell populations are also hit as a side effect. This is the reason why many people on chemo lose their hair; hair follicle cells are susceptible to the same chemo drugs.

Radiation is targeted by aiming a beam at the tumor. By using multiple beams that converge at the tumor site, we can ensure that surrounding tissue receives a lower more tolerable dose.

10

JackD4wkins t1_jdwsofu wrote

Chemo is so toxic that the people administering it cannot even touch it.... and don't get me started on radiation.

These treatments are brutal, carcinogenic in their own rights, and are not even necessarily curative. Crispr enzymes coded specifically to attack cancer DNA has been proven to not affect ANY healthy cells, while selectively annihilating cancer cells in vivo.

6

r0b0c0p316 t1_jdx3zwm wrote

I agree that chemo and radiation are not great options for fighting cancer. The fact that they have off-target effects is a problem, and that's my point; that it's difficult to only target the cancer.

How do you get CRISPR delivered to tumorigenic cells without targeting normal healthy tissue? Targeting anything to specifically hit cancer is tough because cancer presents so similarly to healthy tissue. If you have any papers that discuss this cancer-specific CRISPR targeting I would love to read them because I haven't seen anything about it that's unique to the CRISPR system.

6

JackD4wkins t1_jdxdxlh wrote

You can easily code crispr to target specific strings of DNA. Just take a sample of a patients cancer, analyze which parts of DNA are driving that specific cancer, code your crispr enzyme accordingly, pack it into a virus, and away you go... its really not complicated. Even if the virus infects a healthy cell, the crispr enzyme is specific to cancer DNA and has no effect on healthy dna. The amount of off-target effect is negligible compared to current treatments i.e. chemo and radiation.

The system combines crispr with cancer bioinformatic analysis. Check out CINDELA in sourth korea

2

r0b0c0p316 t1_jdxjxyc wrote

I found this PNAS paper on CINDELA which is a pretty cool proof of concept but it's still far from being an effective treatment (just like the results of the research from the OP). Their mouse experiments were compelling but a lack of comparison between tumor cells vs healthy cells from the same mouse or patient, plus the short time-frame where they administer their sgRNAs means that we can't know for sure what any off-target effects there might be. Also, since it can take as few as 6 driver mutations to generate a cancerous cell, it may not be possible to find 20+ unique indels specific to the cancer but not found in healthy cells.

It could be a promising treatment in combination with other therapies, but there's still a lot more work to be done before its ready for human trials.

4

JackD4wkins t1_jdxkg2x wrote

Once a cell becomes cancerous, the rapid division facilitates further mutation, providing more targets.

Crispr has been shown to have very few off-target indels when coded correctly.

Nevermind other treatments - if we can get this scaled, this may be the silver bullet we stopped believing in

1

r0b0c0p316 t1_jdxmclb wrote

> Once a cell becomes cancerous, the rapid division facilitates further mutation, providing more targets.

That's a fair point, but this also means that tumors have significant heterogeneity, so it can be difficult to find sufficient indels to target. I like your enthusiasm, but this research is still a long ways off from being a 'silver bullet'. Even the paper's authors discuss using it in combination with other treatments.

I'm not saying it won't work; I'm just saying it'll take a lot more funding and research to find out and it's not as simple as you might think.

2

JackD4wkins t1_jdxt1rw wrote

A man can dream haha. I'm partial to multiple rounds of treatment personally. We ID the mutations to target, rip up those cancer cells, then target the remaining ones with different mutations. No chemo/ radiation side effects. It will not be a one-and-done. Will require multiple rounds to take down all of them. The goal is to avoid other treatment modalities completely to avoid their horrific side effects

2

king5327 t1_jdyslcs wrote

Healthy and cancerous cells have almost exactly the same DNA. Minus a few mutations. CRISPR can target them, but might not necessarily be able to do anything useful at those locations.

CRISPR can't tell the difference between cells, it only targets specific sequences. Cancer can be caused by many different mutations, some of which won't cause it on its own. A bad target could lead to complications.

CRISPR has to work on all of the cells, otherwise the stragglers will start a new tumor.

Altogether, for CRISPR to work needs a safe target where the change will be effective and it has to wipe the floor with all of the cancer. Which means the patient needs to be lucky for it to even be a possibility, even if the success rate is high once administered.

(Source: mostly things I've read over the past decade and a half, I may be out of date)

1

JackD4wkins t1_jdyyu13 wrote

Crispr has been demonstrates to act at cancer causing mutation locations. Target selection is vital to success and require targeting multiple different mutations simultaneously.

Bad targeting has been rare and inconsequential in the context of current treatment side effects i.e. chemo and radiation.

Crispr can by used more than once to mop ip stragglers.

2

Kinexity t1_jdwmi96 wrote

Why do we have to complicate the process to meet some arbitrary goal which doesn't make our cure better but rather makes it harder to deploy?

3

JackD4wkins t1_jdwq341 wrote

Exactly, redesigning immune cells is much harder than just vandalizing cancer DNA with the exact same tool...

1

Kinexity t1_jdwrahf wrote

No. It's the opposite. We don't have a reliable methods to attack DNA of cancer cells. Using immune system to do the job for us has been proven to work safely and reliably.

5

JackD4wkins t1_jdws2qf wrote

We do have reliable methods of attacking cancer DNA. Its called CINDELA. The South Koreans beat you to it.

Using the immune system does not work reliably except in a very small subset of cases in a small subset of cancers...

1

Kinexity t1_jdwx3uf wrote

If it works and they pass the trials then more power to them. The paper I saw about it was from last year so it shouldn't be surprising that it did not take off yet and should also be a proof that if it took so much longer to develop than immunotherapy then it was indeed harder to get it to work.

2

IllustriousLP t1_jdz3gy0 wrote

The immunotherapy keytruda destroyed my cancer . I have a rare kind called sarcoma . I believe my diet of cutting carbs and vitamin c iv played a big part in how effective this drug worked for me. More studies need to be done with patients to see how important diet and vitamin c iv really is for effectiveness.

1

Toranagas1 t1_jeb4pwy wrote

I looked at that PNAS paper and it's pretty good, but isn't necessarily a substitute for cancer immunotherapy. The killing here is subject to transduction efficiency from lentivirus, which won't be 100%. You can see it in their data, that therapy doesn't clear the tumor.

Can potentially be very useful when used with cancer immunotherapy as a memory response is what is most likely to full cure the cancer.

1

JackD4wkins t1_jebbuwn wrote

Immunotherapies are very limited in their applicability. They only work for specific variations of specific cancers...

Transduction efficiency does not need to be 100% on the first attempt. Multiple treatments of even just 50% efficacy result in cure with just 7-8 treatments, without the devastation of chemo or radiation. Nobody requires 100% efficacy from one dose for other treatments, why people place such a high standard on transduction is a mystery to me. "If you can't cure it with one shot, then its not worth doing" is the logic of madness

1

Toranagas1 t1_jebh1oa wrote

Aggressive cancers, such as those that are targeted by therapies like CAR-T cells or immune checkpoint inhibitors grow quite fast. I'm not arguing against multiple treatments, and probably it would improve responses, but are also likely to be insufficient to "cure" it, as the cancer cells not destroyed will continue to grow (at worst at a log phase) and you may never quite reach zero. Only a small number of cells need survive to continue growth of the tumor.

Moreover, one notable advantage for CAR-T cell or TIL therapies is that when patients respond very rapidly, there is little time for the tumors to develop escape mechanisms. After clearance there is also often immunological memory that can maintain clearance or control of subsequent growth.

Keep in mind that the method proposed here relies on the ability for the lentivirus to enter the cell of interest. In the same way that tumors that are refractory to treatment often unregulate immunosuppressive molecules to escape the immune system so is this therapy subject to escape by preventing entry.

There is also some stuff about safety of widely infecting cells with lentiviral vectors containing a myriad of gRNAs and hoping there will be no serious off target events, but considering we are already comparing it to another pretty dangerous therapy I will leave that one out. I assume you are primarily referring to CAR-T or TIL when you say immunotherapy.

To be frank, the results from that PNAS paper are really interesting but the degree of killing isn't the most impressive. Very worthwhile studying though. The personalized medicine aspect here is really fascinating.

1

JackD4wkins t1_jec6avt wrote

Reducing the number of cancer cells that survive the first round depends on how we encode the CRISPR enzyme. As long as we can identify a majority of oncogenic mutations - ideally 50+ - then the only limiting factor becomes dose size. With subsequent doses to catch the remaining cancer cells.

And yes theoretically a cancer could evolve to prevent lentivirus mediated transduction... luckily nature provides an near infinite number of viral vectors from which to choose, and we are already using directed evolution to breed specialized cancer-hunting viruses in massive quantities.

Edit: I appreciate you taking the time to point out limitations in the CINDELA method. It helps further improve.

1

Toranagas1 t1_jeca51a wrote

Possibly those things could help, I guess it remains to be experimentally determined. Anyway it's a decent proof of concept paper, although the in vivo data is a little weak.

Btw, they are giving a lot of doses already, every day at lower viral titers, and every 3rd day at high titers up to two weeks. Then they cut the experiments two weeks after that so we don't really get a good sense of how things would fare longitudinally but I can tell you from having read a lot of these papers that all of those mice will die pretty close to the controls, probably delayed by only a few days or a week.

I dont mean to be negative, as I can sense you are excited by the possibilities this strategy brings up, just trying to inject some realistic perspective into the data they show.

1