In brief
- A peripheral 5-HT2A receptor agonist reduced colorectal cancer growth in mice by activating the immune system.
- The compound, IHCH-8110, acts on the 5-HT2A receptor in the gut with preclinical lack of brain penetration; absence of subjective effects in humans has not been established here.
- Combined with an immunotherapy drug (PD-1 blockade), the effect is enhanced; for now, all work is in animals.
A team of Chinese researchers, with participation from Fudan University and the Shanghai Institute of Biochemistry and Cell Biology, has published a finding in the journal Cell that takes LSD out of its usual territory: activating the 5-HT2A receptor—the same one the molecule latches onto to produce a trip—also mobilizes T cells that attack colon tumors. In mice, LSD slowed the growth of colorectal cancer through this pathway.
A receptor with two faces
The 5-HT2A receptor is famous for its role in the effects of LSD on consciousness, but it is not only in the brain: copies of this receptor are also distributed throughout the gut, including the network of enteric glial cells that surrounds the digestive tract. The authors verified that activating 5-HT2A strengthens the immune response mediated by CD8+ T cells against colorectal cancer and slows its growth in the mice studied. The problem is obvious: administering whole LSD to treat colon cancer would involve the full trip as a side effect. So, the team sought a way to harness only the useful part.
IHCH-8110, a peripheral 5-HT2A receptor agonist
To separate both effects, the researchers developed IHCH-8110, a 5-HT2A agonist designed not to cross the blood-brain barrier: it activates the receptor in the body but does not reach the areas of the brain where LSD triggers its psychedelic effects. According to the study, IHCH-8110 slows the progression of colorectal cancer by activating 5-HT2A in enteric glial cells, which induces the production of two immune signals, CXCL10 and interleukin-18, that attract CD8+ T cells to the tumor and activate them there. The result is that tumors considered “cold” from an immunological standpoint—that is, poorly infiltrated by defensive cells and therefore difficult to treat—become more accessible to the body’s own defenses. And when IHCH-8110 is combined with a PD-1 blockade drug, one of the current pillars of cancer immunotherapy, the combined effect improves compared to the PD-1 drug alone.
What this implies
All the work has been done in animal models: mice with colorectal cancer, not people. Moving from there to a treatment tested in patients requires years of development, safety trials, and clinical phase studies that this article does not even begin to cover. The interesting thing about the finding is not that it announces a cure, but that it opens a completely different path for research with LSD: not as a psychotherapeutic tool, but as a key to modulate immunity from outside the brain. This is a distinct research line from the other recent study in which scientists dismantled the LSD molecule piece by piece to explore other properties; the IHCH-8110 abstract does not establish structural derivation from LSD. Psychedelic research thus continues to expand its territory beyond mental health.
Source
- Wen Y, Tang L, Duan W, et al. Targeting peripheral 5-HT2AR enhances antitumor immunity in colorectal cancer. Cell, September 1, 2026.
Educational content written from a harm reduction perspective and with respect for individual freedom. It is not a substitute for advice from a healthcare professional and is not intended to encourage or condemn any drug use.
