SRC and YES1 (Src-family kinases)

Class

Small-molecule SRC/YES1 kinase inhibitor (Type 1.5, binds inactive kinase conformation)

Pathway

Blocks SRC-family kinase catalytic and scaffolding activity, suppressing tumor cell proliferation, survival and migration, and overcoming bypass resistance to other targeted therapies

SRC and YES1 belong to the Src-family kinases, a group of enzymes that sit inside the cell and relay signals from surface receptors — such as growth factor and adhesion receptors — into pathways controlling proliferation, survival, and cell movement. In many cancers, these kinases become persistently active, either through direct mutation or as a compensatory route that tumor cells exploit when another targeted pathway, such as EGFR or HER2 signaling, is blocked by a drug. This compensatory activation, often called bypass signaling, allows tumors to continue growing despite treatment, contributing to acquired drug resistance. An inhibitor that blocks both SRC and YES1 aims to shut down this shared escape route more completely than an agent restricted to a single family member, since tumors can use either kinase somewhat interchangeably. Beyond resistance, Src-family kinase activity is also linked to tumor cell migration and invasion, making these targets relevant to metastatic spread. Because SRC and YES1 participate in normal physiology as well — including tissue maintenance and cell adhesion — modulating them carries the general challenge of separating antitumor effects from disruption of normal signaling. This mechanism is broadly relevant across solid tumor types where bypass resistance to targeted agents is a recognized clinical problem.