Rapamycin / MTOR Rebound effect in 3/12 non-GF and non-Keto patients

[Curious]

yes, negative feedback loops could be mediated by mTORC2, and lead to enhanced MEK/ERK pathway

Dual PI3K/mTOR Inhibitors Induce Rapid Overactivation of the MEK/ERK Pathway...

A strategy could be to as they say in your link “adding an AKT inhibitor following cessation of PI3K or mTOR inhibitors.” like black seed oil (Nigella sativa).

or adding a ERK inhibitor, to prevent rebound.

But then again, different cancers in different organs have different environment inside the cancer cells. Not all cancers respond to AKT inhibitors or ERK inhibition. If they did, cancer would be extinct. We are as always flying in the dark and navigating with crude instruments.

But I name few natural products that come to my mind. Apigenin (Will it be absorbed?), Pterostilbene, Curcumin, Silibinin, fisetin, Kaempferol.

Targeting Ras-ERK cascade by bioactive natural products for potential...

[DeStrider]

I think the best way to prevent a rebound is to keep your dosage at 20 mg or below to be safe.

[LaraPo]

@RapAdmin

I think what she’s suggesting, and that is being done by Pankaj Kapahi

I started taking 0.5mg every day for 5 days and break for 5 days. Today I had my bloodwork done. Many bio markers have improved: WBC, MCHC, MPV, BUN, Creatinine, CKD-EPI, Albumin. In fact, all my bio markers are in normal range.

[desertshores]

@LaraPo

In fact, all my bio markers are in normal range.

That’s good to know.

[RapamycinCurious]

@AnUser

@Krister_Kauppi

@AnUser

High doses had greater benefit in Mannick study on immunosenesence, so it probably doesn’t matter much?

What study was that

It was the Mannick paper from 2014 with everolimus.

Graph A and B are just depending on how much previous exposure they have had to influenza, meaning B is lower exposure. It looks at response to vaccine (immunosenesence), basically building antibodies in response to it. The vaccine was given after a 2 week break suggesting improvements in immune system.

As you can see the higher 20 mg/weekly dose had a larger increase than 5 mg weekly and 0.5 mg daily, but it showed in the study to have more side effects.

I don’t think these graphs show that the 20 mg dose was better: they show differential effects depending on the person’s background exposure to influenza. If anything, I would say even just looking at those two graphs, the 5 mg weekly dose appears slightly better overall. Fig. 2. (Increase in antibody titers to heterologous influenza strains) and Table 3 (Percentages of subjects who seroconverted to heterologous strains of influenza) reinforce that view.

These are mostly small differences regardless — and all of them were with lower doses and a different protocol from the Cohen et al paper.

[AnUser]

20 mg is higher in graph A. But only 5 mg and 0.5 mg crossed the threshold set in the study at 1.2 (black line), for at least 2 variants.

[RapamycinCurious]

This was a very useful bit of investigative reporting plus biochemical reasoning: thanks, Matt! One question:

@McAlister

The paper mentions that 6 of 12 participants exhibited a rebound of phospho-p70S6K. This data came from the sirolimus-alone study

I take it you got this from the paper, not the investigators. Where did it come from? I found the paper unclear as to whether it was the rapa-only group or all groups pooled. The latter would have complicated things a lot.

Thanks,

[RapamycinCurious]

@McAlister

Under normal conditions, mTORC1 inhibits a variety of related signaling pathways, including: IRS1/2, mTORC2, and IGFR. Inhibiting mTORC1 with rapamycin releases this negative feedback (Rozengurt et al. 2014) . These over-activated pathways can then stimulate mTORC1 through, for example, AKT and MEK/ERK. …

It appears that high doses of rapamycin (e.g. 30 and 60 mg) repress mTORC1 activity low enough to activate a variety of compensatory mechanisms. Think of it as the cell’s attempt to maintain homeostasis by upregulating mTOR. I speculate that, as the concentration of rapamycin decreases, these over-activated compensatory mechanisms overshoot in the opposite direction, causing a surge in mTORC1 activity (i.e. the mTOR rebound).

This is very interesting. If this is the correct model, then the key thing to do to avoid mTORC1 overshoot is either to never let the brake off of mTORC1 through continuous dosing, or to avoid inhibiting mTORC2 in the first place so as to prevent the buildup of counterregulatory pressure — something most of us area already trying to do through intermittent dosing.

[McAlister]

@RapamycinCurious

Where did it come from?

I’m glad you found it helpful! The paper links the phospho-p70S6K data to the sirolimus-only study at two spots:

Materials and Methods

Sirolimus pharmacodynamics

mTOR phosphorylates p70S6 kinase (p70S6K) at threonine 389 that most closely correlates with activity in vivo. p70S6K phosphorylation at Thr389 was measured in peripheral blood lymphocytes (PBL) as a potential biomarker of rapamycin activity. Only subjects in the sirolimus-alone study underwent determination of phosphorylated p70S6K.

Results

Pharmacokinetics and pharmacodynamics

We chose to examine a phosphorylation site on the direct mTOR substrate, Thr389 on p70S6K, as a pharmacodynamic marker of sirolimus activity in the sirolimus-alone study.

I hope that clears things up.

mTOR Rebound vs. mTORC2 Inhibition

@RapamycinCurious

If this is the correct model, then the key thing to do to avoid mTORC1 overshoot is either to never let the brake off of mTORC1 through continuous dosing, or to avoid inhibiting mTORC2 in the first place so as to prevent the buildup of counterregulatory pressure

It’s worth clarifying here that mTORC2 inhibition and the mTOR rebound are distinct processes. Inhibiting mTORC2 doesn’t cause the buildup of counterregulatory pressure—it actually opposes it. Here’s why:

Under normal conditions, mTORC1 partially inhibits mTORC2 (Rozengurt et al. 2014). So, inhibiting mTORC1 increases mTORC2. That’s part of why you’ll often see an increase in p-AKT^S473 (a surrogate marker of mTORC2 activity) after dosing with rapamycin. (Zakikhani et al. 2010) shows this phenomenon in MCF-7 breast cancer cells:

If you look at that figure again, you’ll also see an early hint of the rationale for pairing rapamycin with metformin (indicated as “Met” in the figure).

These two figures from (Banerjee et al. 2011) give a nice readout of the in vivo landscape (at least in mouse brains).

mTORC1 Activity Surrogate Marker: pS6^Ser235/236
mTORC2 Activity Surrogate Marker: pAKT^Ser473

Intraperitoneal Injection

• Rapamycin at 2 mg/kg inhibited mTORC1 by ~36% and had no significant effect on mTORC2.
• Rapamycin at 5 mg/kg inhibited mTORC1 by ~76% and increased mTORC2 activity by 402%.
• Rapamycin at 20 mg/kg inhibited mTORC1 by ~88% and increased mTORC2 activity by 126%.

Here are the human equivalent doses for a 70 kg person (HED70), with the large caveat that the bioavailability of intraperitoneal injections is much higher than oral tablets.

• 2 mg/kg → HED70 of 11 mg
• 5 mg/kg → HED70 of 28 mg
• 20 mg/kg → HED70 of 114 mg

In the model I presented earlier, the 2 mg/kg dose is low enough to avoid activating compensatory mechanisms in the cell. The 5 mg/kg dose is high enough to activate compensatory mechanisms, but low enough that it doesn’t compromise mTORC2 function. The 20 mg/kg dose activates compensatory mechanisms and inhibits mTORC2, which is why we see p-Akt^Ser473 decrease from 402% to 126% of the control.

These results are consistent with the idea that doses below 20 mg are not likely to cause a rebound in humans. I speculate that the mice in the 5 mg/kg and 20 mg/kg groups are both likely to exhibit an mTOR rebound as the mTORC1 inhibition of rapamycin wears off. Because of the somewhat antagonistic effects of the mTOR rebound and mTORC2 inhibition, I think the 5 mg/kg group would see the largest rebound.

Aside: I would caution against leaning on the HEDs above to guide your dosing protocol. 1) Those assays were performed in the brain. Thanks to the blood-brain barrier, it’s a near-certainty that most tissues in the body are exposed to higher levels of rapamycin. 2) These doses were given through intraperitoneal injection, which at 8 mg/kg results in blood levels around 1,800 ng/mL after one hour (Johnson et al. 2013).

Summary

Inhibiting mTORC1 releases its usual inhibition of mTORC2 and IRS1/2, which then increases Akt. High levels of Akt increase the counterregulatory pressure against mTORC1 inhibition by inhibiting TSC2 and deactivating PRAS40. As rapamycin’s inhibition of mTORC1 wanes, these compensatory mechanisms likely drive the surge in mTORC1 activity.

Inhibiting mTORC2 with higher doses of rapamycin decreases the magnitude of the rebound because mTORC2 activates Akt. However, IRS1/2 also activate Akt—so a decrease in mTORC2 only partially blunts the rise in Akt. Given the downsides of mTORC2 inhibition, I don’t think this is a wise route.

Currently, I suspect the best way to avoid over-activating Akt is to keep intermittent doses below 20 mg and pair rapamycin with metformin (specifically, I think metformin should be present when rapamycin hits its peak concentration). And the best way to avoid functional mTORC2 inhibition is to avoid high doses and long-term use. How high and how long? I haven’t yet found (or triangulated) satisfactory answers there.

[Agetron]

Matt Kaeberlein says in his recent interview with Peter Attia and David Sabatini… CR Calorie Restriction… or in the article about DR Dietary Restriction. That there are additional biological issues associated with CR/DR… that don’t occur with just rapamycin use.

From the article: Through meta-analysis, we found that rapamycin treatment but not DR significantly increased survival of mice exposed to pathogens.

Using Rapamycin is better than CR/DR… rapamycin does one thing nutrients sensing… affects the one area… while CR/DR affects a variety of biological functions.

[desertshores]

@McAlister

Under normal conditions, mTORC1 partially inhibits mTORC2 (Rozengurt et al. 2014). So, inhibiting mTORC1 increases mTORC2.

I am sorry, to use the Reddit expression, please explain this to me like I am a 5-year-old.

[McAlister]

@desertshores

please explain this to me like I am a 5-year-old

TORC1 and TORC2 are brothers. TORC2 is always trying to get TORC1 worked up, usually by convincing their cousin Akt to switch out TORC1’s decaf for a regular cup of coffee. TORC1 isn’t stupid, though. Usually, he keeps this in check by calming his brother down and getting their dog, S6K, to play with him. TORC1 also knows that their cousin, Akt, is only a trouble maker after she eats a lot of candy. So, he makes sure there isn’t any around. He also enlists their health-conscious grandmother to check for candy, too. But, if TORC1 wakes up tired, he doesn’t have the energy to calm his brother down, forgets to have their dog, S6K, go play with him, forgets to check the house for candy, and doesn’t remind his grandmother to check either. So, TORC2 gets excited, convinces sugar-rush Akt to switch out TORC1’s decaf and now as his morning grogginess wears off, TORC1 suddenly surges back to life.

---

To provide some biological context to that little story, I’ve slightly modified a diagram of the mTOR pathway from Cell Signaling Technologies. On first glance, it’s a lot. But follow the colors: green means activation and red means inhibition. I haven’t modified the right side of the diagram, so we’ll focus on the left.

Start with mTORC1 in the lower left. It activates p70S6K. Trace the red (inhibition) lines upward and you’ll see that p70S6K inhibits Rictor (a central component of mTORC2) and IRS-1 (insulin receptor substrate 1).

Now go back to mTORC1. You’ll see that mTORC1 also inhibits IRS-1. You’ll also see a green line extending to GRB10, which then goes on to inhibit IRS-1.

Now, here’s the same story with some added biological detail:

TORC1 and TORC2 are brothers. TORC2 is always trying to get TORC1 worked up, usually by convincing their cousin Akt to switch out TORC1’s decaf [↓ PRAS40 ↓ TSC2] for a regular cup of coffee [↑ Rheb]. TORC1 isn’t stupid, though. Usually, he keeps this in check by calming his brother down [↓ Rictor ↓ mTORC2] and getting their dog, S6K, to play with him [↓ Rictor ↓ mTORC2]. TORC1 also knows that their cousin, Akt, is only a trouble maker after she eats a lot of candy. So, he makes sure there isn’t any around [↓ IRS-1]. He also enlists their health-conscious grandmother [↑ GRB10] to check for candy, too [↓ IRS-10]. But, if TORC1 wakes up tired [Rapamycin —| mTORC1], he doesn’t have the energy to calm his brother down [↑ Rictor ↑ mTORC2], he forgets to have their dog, S6K, go play with him [↑ Rictor ↑ mTORC2], forgets to check the house for candy [↑ IRS-1], and doesn’t remind his grandmother [↓ GRB10] to check either [↓ IRS-1]. So, TORC2 gets excited, convinces sugar-rush Akt to switch out TORC1’s decaf and now as his morning grogginess wears off [Rapamycin ↓ mTORC1 ↑], TORC1 suddenly surges back to life.

---

It’s important to keep in mind that mTORC1 and mTORC2 participate in a regulatory loop. Most cell signaling works like that, through complicated loops. So, as mTORC1 activity surges back it will begin inhibiting mTORC2 again, which will then decrease the Akt-mediated increase in mTORC1, allowing mTORC1 to decrease, which will then release some of its inhibition of mTORC2, and so on… until the system reaches an equilibrium.

[desertshores]

Have you been playing with Chat GBT?

[SNK]

@desertshores

please explain this to me like I am a 5-year-old

@McAlister I don’t think he meant it literally God job though! Perhaps a kindergarten teacher job could await in your future LOL

[McAlister]

Haha! That was actually an original.

ELI5 challenges require an amusing mix of knowledge and creativity. I had another one going with thermostats and air conditioning, but it was too complex for a five year old—so brothers it was.

[desertshores]

You are very smart and talented. I appreciate your input.

[DeStrider]

@McAlister That was a brilliant explanation. You will probably make a brilliant professor or researcher one day.

Can you explain how AMPK fits into MTORC1 inhibition?

[sunshine4]

Could you give me a little personal advice. I hate to have to ask. I took rapamycin with a large stack. 8 mg a week as a 205 pound man (only for a few weeks, I took lower dosages and daily too over the course of 3-4 months). I took it unknowingly with cyp3a4 inhibitors like I believe apigenin/ginger may be? with fattening oregano oil. Would this have reached into that danger zone? some of my stack acts as a akt inhibitor though like apigenin/ginger I believe.

Would you be hesitant with taking rapamycin with such a large stack?

Ive taken it with the following

Novos (fisetin, magnesium. glycine, glucosamine sulfate, pterostilbene, hyaluronic acid, rhodiola rosea, l theanine, micro dosed lithium, vitamin c, malate, ginger, calcium alpha-ketoglutarate).
donotage sirt 6 activator
liposomal nmn/liposomal apigenin
psyllium husk
ginger with high gingerol
ceylon cinnamon
vitamins a/d/k/b6/b12/magnesium/zinc/copper
krill oil with astaxanthin
beef liver
melatonin 10 g
oregano oil/garlic

Is it best to keep the rapa on a low dose until more is known how these agents affect bioavailibity?

on top of this, multiple of these agents also have some affect limiting mtor don’t they (like melatonin and the herbs)?

[DeStrider]

Did you experience any bad side effects after taking Rapamycin?

[John_Hemming]

Its an interesting mixture. Some AMPK activators, some HDAC inhibitors and a good range.

What I do with rapa when I take it (no more frequently than every 3 weeks) is to take it at about 6.30am and then have my supplements at around 9.30am (or at least a couple of hours later). With a bit of luck the supplements then don’t have much of an effect on serum levels of Rapamycin. I would like to do a blood test.

The different K1 and K2 vitamins matter (there is only 1 K1, but quite a few K2 of which three can be readily supplemented and the rest are available in some types of food), The different K2s have materially different effects.