Small Molecule Discovery Could Open the Door to New Class of Treatments for Hard-to-Treat Cancers (2026)

Imagine a groundbreaking discovery that shatters the myth of 'untouchable' cancer drivers, paving the way for fresh hope in battling stubborn cancers that have defied conventional therapies. That's the exciting reality unveiled by scientists at UCLA Health Jonsson Comprehensive Cancer Center, who have pinpointed a tiny molecule capable of blocking a notorious cancer-fueling protein once deemed impossible to drug – potentially ushering in an entirely new category of therapies for leukemia and other formidable cancers. But here's where it gets controversial: Could this mean we're finally cracking open the door to targeting proteins that have long laughed off drug attempts, or is it just the start of a heated debate on how aggressive we should get in manipulating our body's blueprint?

The molecule in question, dubbed I3IN-002, works by interfering with a protein called IGF2BP3, which normally helps stabilize RNAs that promote cancerous growth – a process that accelerates aggressive types of acute leukemia. A study featured in the journal Haematologica revealed that this compound not only curbs the proliferation of leukemia cells but also prompts their self-destruction and diminishes the pool of leukemia-initiating cells responsible for sustaining the illness. For beginners, think of leukemia-initiating cells as the 'ringleaders' in a cancer gang; they keep the disease going, much like how a few key leaders can perpetuate a rebellion.

This endeavor has spanned over a decade. 'We identified IGF2BP3 years back as a major player in acute leukemias, yet we lacked the means to attack it directly,' explains Dr. Dinesh Rao, a professor of pathology and laboratory medicine at UCLA's David Geffen School of Medicine and the study's lead researcher. 'Proving we can now inhibit this protein and derail its role in cancer cells is truly exhilarating.' IGF2BP3 is part of a group of RNA-binding proteins that are typically only buzzing during the earliest phases of human development, like the foundational crew building a house. After birth, they usually quiet down, but in certain cancers – including leukemia, brain tumors, sarcomas, and breast cancers – IGF2BP3 reactivates. For decades, scientists struggled to craft a drug against it because it doesn't have the usual 'handles' or enzyme spots that most medications grab onto, making it a notoriously tricky target. And this is the part most people miss: RNA-binding proteins aren't your standard cancer foes, as Dr. Rao points out. He's also affiliated with the UCLA Health Jonsson Comprehensive Cancer Center and the UCLA Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research. 'By decoding IGF2BP3's role – essentially clinging to RNAs that encode genes boosting cancer – we devised a test to jam that specific connection,' he adds.

To hunt for a potential blocker, the team employed a high-powered screening tool, sifting through about 200,000 substances from UCLA's Molecular Screening Shared Resource, overseen by Dr. Robert Damoiseaux, to spot those that could prevent IGF2BP3 from attaching to its RNA targets – the central action fueling cancer's spread. After spotting initial promising candidates, Rao collaborated with UCLA chemistry professor Dr. Neil Garg, whose team dissected the compounds' structures and spotted a recurring pattern. This led to I3IN-002 as the standout choice, demonstrating strong potency at very low concentrations and mimicking the effects of completely removing the IGF2BP3 gene. Garg's group then devised a way to produce it in the lab, a crucial move for further evaluation. For context, imagine this like finding the perfect key that unlocks a previously impenetrable safe – but in this case, the safe is protecting cancer's vitality.

With I3IN-002 synthesized, the scientists subjected it to rigorous evaluations to confirm it genuinely impacts IGF2BP3, the cancer culprit they aimed to neutralize. Leukemia cells dependent on IGF2BP3 saw their growth drastically slow upon exposure, whereas cells without the protein barely reacted – clear proof the compound hits its mark. In IGF2BP3-positive cells, it induced apoptosis (a natural, programmed cell suicide process that cancers often evade) and disrupted the protein's RNA-binding ability, a vital link in its cancer-supporting chain. It also lowered levels of several genes that IGF2BP3 typically shields, highlighting its specificity as a potential treatment. These impacts were far milder in cells genetically stripped of IGF2BP3, solidifying that I3IN-002 operates precisely as intended. Further tests, including gene expression analyses, RNA binding checks, temperature shift assays, and stability studies, verified that the molecule physically attaches to IGF2BP3 and modifies its behavior – marking one of the strongest proofs yet that this 'undruggable' family of RNA-binding proteins can indeed be challenged with small molecules.

In early animal trials with mice, the compound exhibited biological effects, including modest anti-leukemia benefits. While the results weren't as robust as anticipated, Rao notes this is par for the course with an initial compound. 'The key is demonstrating we can strike the protein and disrupt its function,' he states. 'This advances not only leukemia studies but the broader arena of RNA-binding proteins in oncology.' The group is now engineering improved versions of I3IN-002 – more powerful, durable, and primed for animal and human trials. 'From creating the assay to screening drugs, validating hits, and analyzing outcomes, this represents a pivotal achievement in our lab,' says Dr. Amit Jaiswal, an assistant project scientist in Rao's lab and the study's primary author. Other contributors from UCLA include Georgia Scherer, Michelle Thaxton, Jacob Sorrentino, Constance Yuen, Milauni Mehta, Gunjan Sharma, Tasha Lin, Tiffany Tran, Amanda Cohen, Robert Damoiseaux, and Neil Garg. Funding came partially from the California Institute of Regenerative Medicine, the National Institutes of Health, the UCLA Health Jonsson Comprehensive Cancer Center, the Gary & Barbara Luboff Mitzvah Fund, and the UCLA Innovation Fund Award, which aids in commercializing promising breakthroughs.

References

https://www.news-medical.net/news/20251209/Small-molecule-discovery-could-open-the-door-to-new-class-of-treatments-for-hard-to-treat-cancers.aspx