On April 28, 2025 Theralase Technologies Inc. (TSXV: TLT) (OTCQB: TLTFF) ("Theralase" or the "Company"), a clinical stage pharmaceutical company dedicated to the research and development of light, radiation, sound and/or drug-activated small molecules and their formulations, intended for the safe and effective destruction of various cancers, bacteria and viruses, reported that RuvidarTM has recently been proven preclinically to be an effective inhibitor of DeUbiquitinating Enzymes ("DUBs"), an important class of enzymes which have been linked to numerous cancers and neurogenerative diseases (Press release, Theralase, APR 28, 2025, View Source [SID1234653899]).

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DUBs cause cellular damage by removing ubiquitin or ubiquitin-like molecules from target proteins.

Ubiquitin is a small protein found in all eukaryotic cells (animals, plants and humans), which plays a crucial role in regulating various cellular processes, such as: gene expression, DNA repair, cytokine signaling, cell metabolism, cell cycle and cell death. It functions primarily through ubiquitination, a process where ubiquitin is conjugated to target proteins, marking them for degradation or altering their activity.

Altered DUBs activity is associated with multitudes of pathologies, including cancer; therefore, DUBs represent novel candidates for target-directed drug development.1

Drug resistance to chemotherapy and molecularly targeted therapies are an ongoing challenge in cancer treatments. The underlying mechanisms of resistance to cytotoxic chemotherapeutics and to drugs that target a specific molecule are not understood completely. In recent years, emerging evidence has frequently suggested that the dysregulation of DUBs plays important roles in the development of drug resistance; hence, DUBs enable cancer cells to escape cell death and survive when exposed to a variety of anti-cancer drugs. Therefore, there exists the potential application of utilizing DUBs inhibitors in combinational therapies to overcome drug resistance.2

Targeting DUBs with inhibitors like Ruvidar is a very promising strategy to overcome drug resistance.

In previous Theralase research, it was demonstrated that Ruvidar induces oxidative stress in cells through the production of Reactive Oxygen Species ("ROS").

In the latest research, we have investigated the effects of Ruvidar on DUBs activity and have demonstrated that Ruvidar inhibits DUBs activity in a dose-dependent manner.

This direct inhibition of DUBs, coupled with the known production of ROS by Ruvidar, are an exciting new combination of the mechanisms of action of the effects that Ruvidar has on cancer cells, leading to a significant reduction in cancer cell growth.

Dr. Mark Roufaiel, Research Scientist, Theralase stated, "Our latest research provides compelling evidence that RuvidarTM not only induces oxidative stress through the production of ROS to destroy cancer cells, but also directly inhibits DUBs activity-a key host mechanism exploited by the cancer cell to evade immune defenses. This dual mechanism positions Ruvidar as a promising therapeutic candidate, particularly against cancers, where traditional chemotherapeutics demonstrate limited effectiveness."

Arkady Mandel, M.D., Ph.D., D.Sc., Chief Scientific Officer, Theralase stated, "With the increasing prevalence of chemoradiotherapy resistant cancers, Ruvidar, as an effective DUBs inhibitor, may be indispensable clinically to be used as a combinational therapy with various chemotherapy drugs and/or radiotherapy to provide a safe and effective treatment against various forms of chemoradiotherapy resistant cancers. The discovery of Ruvidar’s effectiveness against DUBs is a notable milestone in the development of Theralase’s small molecule program and can be used for treating cancer, but could be expanded far beyond this to the treatment of age associated medical conditions, various neurodegenerative diseases, such as Alzheimer’s, Parkinson’s and Multiple Sclerosis, as well as to effectively combat various infectious diseases".

Roger DuMoulin-White, B.Sc., P.Eng., Pro.Dir., President and Chief Executive Officer, Theralase stated, "According to recent peer-reviewed research, reducing DUBs plays a very important role in the war against cancer and its innate ability to build up drug resistance. This latest research reinforces an additional mechanism of action beyond direct cancer destruction and indirect immune stimulation, stripping away one of cancer’s final defence mechanisms. As Theralase pursues clinical development of Ruvidar for numerous cancers, such as brain and lung cancer, I look forward to reporting out on the clinical safety and efficacy of these programs."