Does spike protein kill prostate cancer cells?

Yeah but...

I’d like to nominate this paper for having The Most Misleading Conclusion of the Year:

SARS-CoV-2 spike protein inhibits growth of prostate cancer: a potential role of the COVID-19 vaccine killing two birds with one stone

Here’s a brief background:

The spike protein is a type of protein on the surface of the SARS-CoV-2 virus. The COVID vaccines work by getting the body to produce this protein, with some modifications. 

Here’s what the study did, in a nutshell:

They exposed human prostate cancer cells to different concentrations of spike protein.

Here’s what the study showed, in one sentence:

Prostate cancer cells die when exposed to the spike protein.

Based on that, they say in their conclusion:

These results suggest a potential additional benefit of COVID-19 vaccination by providing a means of exposing prostate cancer cells to SARS-CoV-2 spike protein.

Based on that, we see headlines like this:

The article asks if individuals with prostate cancer could face potential harm from getting a COVID-19 vaccine. It then says that according to this recent study, the spike protein made by the vaccine “actually reduces the survival of the cancer cells.”

Great, right?

The problem is that spike protein kills other cells too.

It’s like if they had found out that lead killed prostate cancer cells and then concluded their paper with:

These results suggest a potential benefit of drinking water from Flint, Michigan by providing a means of exposing prostate cancer cells to lead.

The authors of the paper seemed to be completely unaware of the numerous studies out there that show that spike protein damages cells rather indiscriminately.

Spike protein is cytotoxic to other cells at concentrations similar to what was used in the prostate cancer paper

It would be one thing if this study had shown that spike preferentially kills cancer cells; after all, a lot of cancer treatments are toxic to cells in general, but are used on the rationale that they are more harmful to cancer cells than other cells.

So I could maybe see spike protein being helpful if cancerous cells were more susceptible to it compared to other cells. If that were the case, we’d want to see that a low concentration of spike protein killed cancer cells, but that same concentration did not affect other, vital cells.

That’s unfortunately not the case.

In this study, the lowest concentration they used was 20 ng/mL, which should come out to be a concentration of about 0.14 nM.

[UPDATE: An earlier version of this article had the wrong concentration written above. The way this was calculated was as follows: the paper mentioned using spike protein from BioLegend, San Diego, CA. Although they don’t specify exactly which one they used, I assumed the weight would not be far off from what was here, which is used for bioassays. That has a molecular mass of about 139 kDa = 2.31 x 10^-19 g. So that is the weight of one spike. One mole of spike should then be 1.39 x 10^5 g. In the study they used 20 ng/ml which when you do the conversions should come to 1.44 x 10^-10 mol/L or 0.14 nM]

It looks like that concentration kills about half of the prostate cancer cells present, at least under these in vitro conditions:

Taken from Fig 1 of the study. Graph shows the results of a survival assay which measures percent of prostate cancer cell colonies that survived when subjected to different spike protein (SP) concentrations: 20 ng/mL, 50 ng/mL, 200 ng/mL for 72 h. Cx = the control group, which was just in growth medium for the same timeframe. Colony numbers were quantified as a total percentage of colonies in the control group.

But according to this other study, the S1 and S2 subunits of spike disrupted the integrity of an in vitro model of the human blood-brain barrier with concentrations as low as 0.1 nM (Fig 3A & 3B).

And in this study, S1 at concentrations as low as 10 nM disrupted the barrier of human lung microvascular endothelial cells (Fig 4B).

And in this study, S1 disrupted synthetic lipid membranes similar to cellular membranes at a concentration as low as 40 nM (Fig 2).

More on spike protein toxicity here and here.

These concentrations were on par to what was used in the prostate cancer cell study, which as mentioned above was about 0.14 nM. There are some nuances to consider here: for one, toxicity from just S1 or S2 as separate subunits could be different than from intact spike. It’s also difficult to compare the concentrations precisely across the studies since they all used different spike proteins than what was used in the prostate cancer study, and therefore might have had slightly different weights.

The concentrations cited here were also done under in vitro conditions; the concentrations needed to see the effects under physiological conditions might be different. We also don’t know what percentage of spike exists as intact spike vs S1 and S1 subunits under physiological conditions.

But this is the best we’ve got for the time being. And based on that, it’s rather misleading to suggest that the vaccines could provide “a potential additional benefit” to prostate cancer patients, especially when spike protein could be poking holes in the blood-brain barrier.

How could the authors justify their conclusion?

I could maybe understand not having come across any of the studies on spike toxicity; after all, they haven’t really been covered in mainstream media outlets. But hasn’t everyone heard that the COVID vaccines can cause myocarditis? Didn’t it occur to the authors that the effect they saw in prostate cancer cells could also happen in heart cells?

I’m not even saying that heart cells would die in the same way as prostate cancer cells. We don’t know enough about that yet. But it’s odd that the authors wouldn’t make any connections here. How much mental compartmentalization would you have to engage in, in order to not make any speculation about what spike protein might do to heart cells?

Is it just that the groupthink is so strong that the only way that the researchers could interpret their data was in a way that was positive for the vaccines? Because everybody knows that the vaccines are exceptionally safe and effective?

More on how safe these vaccines are here.

By the way, the CDC still has misinformation on its site about the spike protein:

It calls it “harmless.”

An interesting acknowledgement

Here’s the other thing.

In their title, the authors of the paper suggest that the COVID vaccines could “kill two birds with one stone”; by that they mean that the vaccines could protect against COVID and kill prostate cancer cells, which would have to mean that either the vaccine or spike protein could travel away from the injection site to the prostate.

How come the authors don’t think that it’s disturbing that we could have spike protein reaching the prostate?

Here’s the one thing they do say about this:

The clinical utility of this data is also tempered by the fact that there still remains uncertainty as to how widely the SARS-CoV-2 spike protein distributes following vaccination, and for how long.

Yes, it’s “tempered” by that fact indeed. There needs to be a word or phrase to describe these kinds of strange understatements you sometimes find in scientific literature.

As discussed elsewhere, we don’t know how widely spike distributes or for how long, or even how much spike protein gets produced.

What else did this paper show?

In addition to showing that prostate cancer cells die when exposed to spike, this paper also showed that some markers of cell proliferation go down, and some markers of apoptosis go up. Apoptosis, or programmed cells death, is a process whereby cells kill themselves in a regulated manner. It occurs regularly in multicellular organisms, in order to get rid of damaged or cancerous cells.

All kinds of toxins, as well as stresses like heat, radiation, hypoxia, pH changes, nutrient deprivation, and viral infections, can cause a cell to undergo apoptosis. Apoptosis, as a way of dying, is not unique to cancer cells. And down-regulation of pro-proliferation proteins, isn’t unique to treatments that specifically target cancer cells.

Yet one might be misled into thinking that, because of all the connections with cancer that are made in the conclusion.

For example, in this study they showed that exposure to spike led to down-regulation of a protein called CDK4. CDK4, and CDKs in general, are involved in regulating some of the steps that ultimately lead to cell proliferation.

The authors mention that “Dysregulation among these molecules often results in inappropriate cell proliferation, which makes dysfunctional CDK-pathways a common finding in many cancers” and that “emerging therapeutic strategy in cancer treatment is the use of CDK inhibitors which would downregulate the overactive pro-proliferative molecules such as CDK4.”

It’s true that a lot of cancer therapies focus on targeting molecules or proteins involved in cell proliferation; because cancer cells grow fast, by targeting these proteins, the hope is that you’d disproportionately harm cancer cells compared to other cells. But this is all a distraction because, again, there isn’t anything here to suggest that spike protein specifically targets cancer cells. Maybe if they had also repeated these experiments in normal prostate cells and compared the results with cancerous prostate cells, they could say something like this. But they didn’t.

In their conclusion they seem to indicate that they are aware that spike might not be specific to cancerous prostate cells:

Considering the preferential binding SARS-CoV-2 spike protein has for ACE2 receptors, it is interesting to note that in addition to the high expression of ACE2 receptors in the lungs, several studies have found increased expression of ACE2 receptors in the prostate epithelium, kidneys, and testes, showing that the male genitourinary system may serve as a target-rich environment for SARS-CoV-2 spike protein binding.

In their review on the effects of COVID-19 on the male reproductive system, He et al. found damage to testicular cells and impaired spermatogenesis and proposed that the pathology is due to both direct interactions of SARS-CoV-2 and ACE2 receptors...

They seem to be implying that SARS-CoV-2, and hence, spike protein, damages normal testicular cells. In other words, the damage spike does, is not specific to prostate cancer cells.

So what do the authors really think? Hell if I know. Their thinking appears quite muddled.

Elsewhere in the conclusion, the authors mention that their lab will conduct more research to study the effect of spike on lung and cervical cancer cell lines. Fine: we can look at how spike affects different cell lines, but let’s not pretend that this vaccine could provide some “additional benefit” to cancer patients; not when spike protein could be poking holes in their blood-brain barrier or giving them myocarditis.

This paper needs a new title

The title of this paper should be changed to something like: “Yet another study showing that spike protein is harmful- this time it happens to be in a prostate cancer cell line.”

That title would be less misleading than the “spike protein might help you with your cancer” vibe that the current title gives off.

Show me that spike protein preferentially kills cancer cells, and maybe you could begin to make an argument that this vaccine is somehow killing “two birds with one stone.” But even if that were the case, if you’re killing heart or brain cells, is it worth it? Maybe if we’re talking about a particularly deadly kind of cancer?

Or maybe the idea is to inject men with the vaccine directly into their prostates? (Not that the vaccine would stay there.)

In fact, we should be looking for the opposite effect

It gets worse. There’s actually some evidence that the vaccines could exacerbate or lead to cancer:

Cancers coming back with a vengeance is very common after the COVID vax

I haven’t looked at all the evidence for this carefully so I have no strong opinions on whether this is happening. What I will say, is that in addition to what was in Kirsch’s article above, we have some evidence that the COVID vaccines lead to a temporary drop in levels of lymphocytes, which could mean increased susceptibility to infections and cancer, at least temporarily.

I hope to explore that more in a future article.

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