Given the increasing role of inhibitors of autophagy, I would like to discuss the choice of an inhibitor of autophagy, as well as the possibility of enhancing their effect.
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This study focuses on the comparison of some of these inhibitors:
2015 http://thejns.org/doi/10.3171/2014.12.FOCUS14748
"...the authors of this study set out to investigate whether chloroquine (CQ) analogs, in particular clinically established antimalaria drugs, would also be able to exert antitumor properties, with a specific focus on glioma cells.
...the authors treated different glioma cell lines with quinine (QN), quinacrine (QNX), mefloquine (MFQ), and hydroxychloroquine (HCQ) and investigated endoplasmic reticulum (ER) stress–induced cell death, autophagy, and cell death.
All agents blocked cellular autophagy and exerted cytotoxic effects on drug-sensitive and drug-resistant glioma cells with varying degrees of potency (QNX > MFQ > HCQ > CQ > QN)."
Thus, it follows from the study that cloroquine (CQ) shows a weak effect, even lower, that hydroxychloroquine (HCQ) (?!) Maybe this explains the choice of hydroxychloroquine instead of chloroquine in some tests?
And another quotes from the study:
"Cytotoxicity of QBAs for Glioma Cells:
To determine whether other quinoline-based antimalarial (QBA) compounds could mimic the cytotoxic effects of CQ in glioma cells, we used MFQ and QNX. Results showed that these drugs effectively killed U251 cells at much lower concentrations than CQ."
Blocking Autophagy and Inducing Apoptosis in Glioma Cells:
Based on information that CQ induces apoptosis by blocking autophagy, we analyzed whether the other QBA compounds can function in a similar manner.
Quinacrine, the most potent QBA, not only blocked autophagy, but at 20 μM it completely disrupted U251 cellular functioning, which was evidenced by a high level of PARP cleavage, as well as the absence of CHOP/GADD-153 and LC3B expression.
In Vivo Antitumor Activity:
The TUNEL assay for apoptosis demonstrated a significant increase in the number of TUNEL-positive cells in QNX- and QN-> MFQ-> CQ-treated tumors, as compared with untreated controls."
There are also many reports of another inhibitor of autophagy - 3-methyladenine (3-MA).
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Since many people here take chloroquine, I would like to discuss the possibility of enhancing its effect. While I see there are the following options:
chloroquine + cimetidine
"Cimetidine pre-treatment caused a 53% decrease in the clearance rate of chloroquine, and a 49% increase in the elimination half-life. Cimetidine inhibited the conversion of chloroquine to monodesethylchloroquine in terms of reductions in the AUC, Cmax, and urinary excretion of monodesethylchloroquine. The serum Cmax of chloroquine was increased by approximately 30% in the cimetidine pre-treated group."
The downside is that since there are many medicines in the cocktail, numerous unpredictable interactions with cimetidine are possible.
increase in the dose of Chloroquine
Instead of using cimetidine, can it be easier to increase the dose of Chloroquine? The standard is 250 mg / day.
chloroquine + hypoxia-inducing agents
2017 https://www.ncbi.nlm.nih.gov/pubmed/28797031
"This work shows that inhibition of autophagy is a promising strategy against GBM and identifies ATG9 as a novel target in hypoxia-induced autophagy. Combination with hypoxia-inducing agents may provide benefit by allowing to decrease the effective dose of autophagy inhibitors."
What hypoxia-inducing agents are they talking about?
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I also found several preliminary studies on the synergy of chloroquine and other drugs. It is interesting to study more ..
Dihydroartemisinin + Сhloroquine
2017 https://www.ncbi.nlm.nih.gov/pubmed/29033794
Dihydroartemisinin Exerts Anti-Tumor Activity by Inducing Mitochondrion and Endoplasmic Reticulum Apoptosis and Autophagic Cell Death in Human Glioblastoma Cells.
"Co-treatment with chloroquine (CQ) significantly induced the above effects. Furthermore, ER stress and mitochondrial dysfunction were involved in the dihydroartemisinin-induced autophagy."
Asparaginase + Сhloroquine
2017 https://www.ncbi.nlm.nih.gov/pubmed/29207624
"combination treatment with autophagy inhibitor CQ significantly enhanced anti-glioblastoma efficacy of asparaginase in U87MG cell xenograft model."
Sorafenib + Сhloroquine
2016 https://www.ncbi.nlm.nih.gov/pubmed/26971793
"we combined sorafenib treatment in GBM cells (U373 and LN229) and tumors with the autophagy inhibitor chloroquine. We found that blockage of autophagy further inhibited cell proliferation and migration and induced cell apoptosis in vitro and in vivo. These findings suggest the possibility of combination treatment with sorafenib and autophagy inhibitors for GBM."
___________________________________
2015 http://thejns.org/doi/10.3171/2014.12.FOCUS14748
"...the authors of this study set out to investigate whether chloroquine (CQ) analogs, in particular clinically established antimalaria drugs, would also be able to exert antitumor properties, with a specific focus on glioma cells.
...the authors treated different glioma cell lines with quinine (QN), quinacrine (QNX), mefloquine (MFQ), and hydroxychloroquine (HCQ) and investigated endoplasmic reticulum (ER) stress–induced cell death, autophagy, and cell death.
All agents blocked cellular autophagy and exerted cytotoxic effects on drug-sensitive and drug-resistant glioma cells with varying degrees of potency (QNX > MFQ > HCQ > CQ > QN)."
Thus, it follows from the study that cloroquine (CQ) shows a weak effect, even lower, that hydroxychloroquine (HCQ) (?!) Maybe this explains the choice of hydroxychloroquine instead of chloroquine in some tests?
And another quotes from the study:
"Cytotoxicity of QBAs for Glioma Cells:
To determine whether other quinoline-based antimalarial (QBA) compounds could mimic the cytotoxic effects of CQ in glioma cells, we used MFQ and QNX. Results showed that these drugs effectively killed U251 cells at much lower concentrations than CQ."
Blocking Autophagy and Inducing Apoptosis in Glioma Cells:
Based on information that CQ induces apoptosis by blocking autophagy, we analyzed whether the other QBA compounds can function in a similar manner.
Quinacrine, the most potent QBA, not only blocked autophagy, but at 20 μM it completely disrupted U251 cellular functioning, which was evidenced by a high level of PARP cleavage, as well as the absence of CHOP/GADD-153 and LC3B expression.
In Vivo Antitumor Activity:
The TUNEL assay for apoptosis demonstrated a significant increase in the number of TUNEL-positive cells in QNX- and QN-> MFQ-> CQ-treated tumors, as compared with untreated controls."
There are also many reports of another inhibitor of autophagy - 3-methyladenine (3-MA).
___________________________________
Since many people here take chloroquine, I would like to discuss the possibility of enhancing its effect. While I see there are the following options:
chloroquine + cimetidine
"Cimetidine pre-treatment caused a 53% decrease in the clearance rate of chloroquine, and a 49% increase in the elimination half-life. Cimetidine inhibited the conversion of chloroquine to monodesethylchloroquine in terms of reductions in the AUC, Cmax, and urinary excretion of monodesethylchloroquine. The serum Cmax of chloroquine was increased by approximately 30% in the cimetidine pre-treated group."
The downside is that since there are many medicines in the cocktail, numerous unpredictable interactions with cimetidine are possible.
increase in the dose of Chloroquine
Instead of using cimetidine, can it be easier to increase the dose of Chloroquine? The standard is 250 mg / day.
chloroquine + hypoxia-inducing agents
2017 https://www.ncbi.nlm.nih.gov/pubmed/28797031
"This work shows that inhibition of autophagy is a promising strategy against GBM and identifies ATG9 as a novel target in hypoxia-induced autophagy. Combination with hypoxia-inducing agents may provide benefit by allowing to decrease the effective dose of autophagy inhibitors."
What hypoxia-inducing agents are they talking about?
___________________________________
I also found several preliminary studies on the synergy of chloroquine and other drugs. It is interesting to study more ..
Dihydroartemisinin + Сhloroquine
2017 https://www.ncbi.nlm.nih.gov/pubmed/29033794
Dihydroartemisinin Exerts Anti-Tumor Activity by Inducing Mitochondrion and Endoplasmic Reticulum Apoptosis and Autophagic Cell Death in Human Glioblastoma Cells.
"Co-treatment with chloroquine (CQ) significantly induced the above effects. Furthermore, ER stress and mitochondrial dysfunction were involved in the dihydroartemisinin-induced autophagy."
Asparaginase + Сhloroquine
2017 https://www.ncbi.nlm.nih.gov/pubmed/29207624
"combination treatment with autophagy inhibitor CQ significantly enhanced anti-glioblastoma efficacy of asparaginase in U87MG cell xenograft model."
Sorafenib + Сhloroquine
2016 https://www.ncbi.nlm.nih.gov/pubmed/26971793
"we combined sorafenib treatment in GBM cells (U373 and LN229) and tumors with the autophagy inhibitor chloroquine. We found that blockage of autophagy further inhibited cell proliferation and migration and induced cell apoptosis in vitro and in vivo. These findings suggest the possibility of combination treatment with sorafenib and autophagy inhibitors for GBM."
A study like this showing in vitro potency of drugs against a target is of limited value when questions of clinical pharmacokinetics aren't taken into consideration. Every drug has different dosing regimen, different toxicity profile, and different levels of free drug achievable in plasma, with dosing limited by the appearance of toxic side effects.
ReplyDeleteSo yes, *in vitro* quinacrine and mefloquine may be the most potent, chloroquine intermediate, and quinine least potent. However in the body, achievable levels of free quinacrine and mefloquine are the lowest, chloroquine and quinine the highest. As a general rule, the more potent drugs (in terms of in vitro IC50) are used with lower dosing and achieve lower plasma levels than drugs with lower potency.
It's possible to increase the effective dose of chloroquine, either by taking with cimetidine, or simply increasing the ingested dose. However as the dose goes higher, so does the chance of adverse side-effects.
ReplyDeleteCould it be that adding cimetidine increases the possibility of adverse side effects of chloroquine, as well as simply increasing the dose of chloroquine without adding cimetidine ?
DeleteIn both cases, the clearance rate of chloroquine decreases and the elimination half-life is increased.
Now I'm looking for information on what maximum dose of chloroquine can be well tolerated and think about the need to add cimetidine...
DeleteIn trials in Mexico, the dose of chloroquine for 12 months was 150 mg / day (=250mg Delagil)
By the way, in the study with metastatic melanoma a conclusion is made about the recommended dose of HCQ for phase 2:
2014 https://www.ncbi.nlm.nih.gov/pubmed/24991839
MTD was not reached for HCQ and the recommended phase II dose was HCQ 600 mg twice daily.
2016 https://www.ncbi.nlm.nih.gov/pubmed/27463016
Patients received HCQ 600 mg orally daily for a 3-week cycle. The dose was well tolerated.
And yet not clear conclusion about how to take CQ:
2016 https://www.ncbi.nlm.nih.gov/pubmed/27226909
Khat-chewing (?) was found to significantly reduce plasma CQ levels among healthy volunteers and malaria patients. While receiving CQ treatment, patients should be advised not to chew khat (?).
Higher doses of chloroquine are tolerable when treating malaria, but this use is short-term.
DeleteRisks of long-term use is related to retinal damage (in the eye).
"Irreversible retinal damage has been observed in some patients who had received long-term or high-dosage 4-aminoquinoline therapy. *Retinopathy has been reported to be dose related.*
When prolonged therapy with any antimalarial compound is contemplated, initial (base line) and periodic ophthalmologic examinations (including visual acuity, expert slit-lamp, funduscopic, and visual field tests) should be performed."
According to the literature, “The risk of developing toxic retinal chloroquine damage seems to be small or absent even in long term treatment, providing the dose is kept low, not higher than 0.25 g [250 mg chloroquine phosphate] daily for 10 months annually, and the patient is under 50 years old and does not suffer from any other illness which might affect the retina. The total annual dose is thus 70-75 g. Regular ophthalmological checks should then not be essential. In elderly patients, over 50-60, in whom there is the problem of differentiating senile maculopathy from chloroquine-induced maculopathy, regular ophthalmological check-ups are advised.”
http://btcocktails.blogspot.com/p/toxicities.html
https://www.ncbi.nlm.nih.gov/pubmed/981992
The long term metronomic dose of chloroquine when used for rheumatoid arthritis is the same as used in the brain tumor trials 250 mg chloroquine phosphate (~150 mg chloroquine base). You might be able to get away with combining it with cimetidine (which has the effect of increasing plasma levels by inhibiting its metabolism to desethylchloroquine), but in that case regular eye exams may be even more important.
A study from 1959 experimenting with even higher daily doses can be found here:
http://annals.org/aim/article-abstract/677362/chloroquine-phosphate-aralen-long-term-treatment-rheumatoid-arthritis
I will upload this study to the Brain Tumor Library sometime today.
Hydroxychloroquine doses can't be used to inform chloroquine dosing - they are different drugs.
I've never heard of khat. But if it does have that interaction with chloroquine I would avoid it.
Thank you very much, Stephen, for your time, you spend on this blog and your detailed answers to even the most uninteresting questions.
DeleteYou're welcome! The 1959 study on long-term chloroquine for rheumatoid arthritis is in the Brain Tumor Library: folder 1 (Therapies - human studies) -> Chloroquine
DeleteIn general, hypoxia isn't something you want to deliberately induce, as it increases the invasive, migratory behaviour of cells. However, GBM typically has large areas of hypoxia in the center of the tumor, and autophagy is a natural coping mechanism to this natural hypoxia. Also bevacizumab tends to increase hypoxia, and is likely the reason BEV + chloroquine was shown to be synergistic in mouse models.
ReplyDeleteDihydroartemisinin is the active metabolite of many of the artemisia-derived agents (artesunate, artemisinin), and is available commercially.
ReplyDeletehttp://hepalin.com/products.htm
Asparaginase is a drug used in acute lymphoblastic leukemia and even in the less expensive form (Elspar) would run ~$1000 USD per month at standard dosing.
Sorafenib is a drug for hepatocelluar and renal cancers running ~$6000 USD per month at standard dosing.
Drug costs from this document:
https://www.mskcc.org/sites/default/files/node/25097/documents/120915-drug-costs-table.pdf
Correct me if I’m wrong but THC inhibits authophagy.
ReplyDeleteTHC is an *inducer* of autophagy. It can kill cancer cells through autophagy-mediated mechanism, and autophagy inhibition with chloroquine can actually work against THC.
Deletehttps://www.ncbi.nlm.nih.gov/pubmed/25674907
Autophagy is complicated and context-dependent. Sometimes it can be a survival mechanism, and other times it can be a death-mechanism.
Before GBM, I used to think that autophagy was meant only as a death mechanism but yes, now I realize that it’s much more complex than that.
DeleteThis is the conclusion drawn in one of the Russian-language studies in 2016:
ReplyDeleteApparently, autophagy plays a suppressor role in the development of tumors in the early stages of cell transformation, and for already formed tumors autophagy performs a protective function, giving its cells resistance to chemotherapy, which leads eventually to a rapid progression of the disease.
At present, clinical studies of inhibitors of autophagy are actively underway, the use of which in the therapy of malignant neoplasms seems promising. But we must take into account that these inhibitors can be effective at one stage of the cancer and work in the opposite direction at another stage.
What conclusion can we draw?
DeleteThat inhibition of autophagy is useful for a large tumor volume and is undesirable for a fully removed tumor?
"Apparently, autophagy plays a suppressor role in the development of tumors in the early stages of cell transformation"
DeleteCells left behind after a glioblastoma total resection are not in the early stages of cell transformation. Glioblastoma cells are at a late stage of cell transformation by definition.
Autophagy inhibition on its own might be more useful in the hypoxic center of a GBM, because autophagy is a coping mechanism in low oxygen conditions, so in this context it wouldn't be as useful after a complete resection. In the context of EGFR-driven tumors, autophagy inhibition could be generally useful due to their increased reliance on autophagy.
EGFR overexpressing cells and tumors are dependent on autophagy
for growth and survival
https://www.ncbi.nlm.nih.gov/pubmed/23891088
Perhaps an interesting article. Does anyone have the full version of this article?
ReplyDelete2016 https://www.ncbi.nlm.nih.gov/pubmed/26687632
"The present article reviews the several known direct and indirect effects of different doses of Chloroquine on cancer and how those effects may indicate that a fine tuning of the dose/schedule of Chloroquine administration versus chemotherapy may be critical to obtain an adjuvant effect of Chloroquine in anti-cancer treatments. We anticipate that the appropriate (time and dose) addition of Chloroquine to the standard of care may greatly and safely potentiate current anti-cancer treatments."
I found:
Deletehttp://crescopublications.org/pdf/CROOA/CROOA-2-012.pdf
Is there any thought of a dietary supplement rutin as an inhibitor of autophagy for a double action with chloroquine?
ReplyDeletehttps://www.ncbi.nlm.nih.gov/pubmed/28293765
Rutin was injected intraperitoneally, not administered orally. It's not certain therapeutic levels could be achieved when given orally. It's still an interesting outcome though, seeing that rutin can be purchased commercially without a prescription.
Delete