Acute myeloid leukemia (AML) continues to present an immense challenge in oncology due to its aggressive nature and resistance to conventional therapies. Despite advances in drug development, combinatorial drug regimens have often outperformed monotherapies in clinical settings, yet the intricate molecular mechanisms underlying these synergistic effects have remained elusive. A recent breakthrough study published in Nature Communications has unveiled a novel proteomics-based approach, CoPISA (Combinatorial Proteome Integral Solubility/Stability Alteration), that elucidates how drug combinations uniquely remodel the soluble proteome, offering unprecedented insights into the molecular choreography of combinational cancer therapy.
Led by Senior Research Fellow Mohieddin Jafari at Tampere University, this study marks a paradigm shift in understanding therapeutic synergy at the proteome-wide scale. Unlike prior methods that merely detect whether drugs act synergistically, CoPISA delivers a mechanistic panorama by capturing dynamic alterations in protein solubility and stability across thousands of proteins simultaneously. This approach discerns both direct drug targets and collateral downstream effectors, enabling researchers to decode the cellular network perturbations engendered exclusively by combined drug actions, which are invisible when drugs are evaluated as single agents.
The research team applied CoPISA to two promising AML drug pairs: the combination of LY3009120, a pan-RAF inhibitor, with sapanisertib, an mTORC1/2 inhibitor (denoted LS), and ruxolitinib, a JAK1/2 inhibitor, paired with ulixertinib, an ERK1/2 inhibitor (denoted RU). These combinations had previously demonstrated robust anti-leukemic efficacy with minimal toxicity in multiple AML cell lines, patient-derived samples, and in vivo zebrafish xenograft models, but their synergistic molecular underpinnings remained speculative. By deploying CoPISA, Jafari and colleagues provided a high-resolution mechanistic map that reveals how each combination dismantles the leukemia cellular machinery through distinct yet complementary pathways.
CoPISA’s innovation lies in its ability to simultaneously profile thousands of proteins’ solubility and thermal stability changes following treatment, a physicochemical signature indicative of altered protein conformations, interactions, and functional states. This technique transcends traditional binding assays by identifying proteins indirectly affected by treatment, including those in complex signaling cascades or post-translational modification networks. Importantly, CoPISA identifies emergent “AND-gate” or conjunctional targeting effects, wherein proteins exhibit significant alterations only when exposed to both drugs in combination—an effect utterly absent in single-agent treatments.
A striking finding was the identification of conjunctional targeting of critical AML-related proteins such as DNMT3A, NPM1, and TP53. These proteins, central to leukemogenesis and disease progression, remained refractory to single drugs but were selectively destabilized or solubilized by the drug combinations. This revelation unveils previously hidden vulnerabilities in AML cells, providing a molecular rationale for combination therapy’s superior efficacy. Such conjunctional targeting implies that the drug pairs enforce specific molecular conditions simultaneously to overcome resistance mechanisms and disrupt oncogenic signaling dependencies.
Further mechanistic dissection revealed that the LS combination predominantly reconfigures processes associated with SUMOylation, chromatin condensation, mitotic regulation, and VEGF-mediated cell adhesion. These alterations signify a coordinated disruption of genomic stability and cell division, effectively halting leukemia cell proliferation. On the other hand, the RU combination perturbs a distinct set of pathways, prominently impairing DNA damage checkpoint controls, mitochondrial energy metabolism, and RNA splicing machinery. This mechanistic divergence highlights the specificity of proteome remodeling by different drug pairs, underscoring the adaptability of AML cells to unique stressors imposed by varied therapeutic regimens.
Such detailed proteome-level signatures permit an unprecedented understanding of how combination therapies function as integrated systems, rather than merely additive effects of two drugs. By revealing non-linear biological responses and emergent molecular phenotypes, CoPISA provides a platform to rationally design drug combinations that maximize synergy, minimize toxicity, and circumvent resistance mutations. This approach could be transformative in guiding precision oncology, where patient-specific molecular contexts demand carefully tailored combination regimens.
Jafari emphasizes that the implications of CoPISA extend beyond AML. Because its readout is based on general physicochemical changes in protein solubility and stability, it is broadly applicable across cancer types and therapeutic classes, including targeted agents, chemotherapeutics, and immunomodulators. The capacity to delineate mechanistic signatures from drug combinations enables a systems biology approach to uncovering new drug targets and resistance pathways, potentially accelerating drug discovery and repurposing efforts.
The research team is currently expanding the application of CoPISA into acute lymphoblastic leukemia (ALL), reporting preliminary results that mirror the mechanistic insights obtained in AML. These early findings signal a promising future for CoPISA-enabled investigations into diverse hematological malignancies and solid tumors. Moreover, by refining and scaling this workflow, it may soon become a routine component of preclinical drug development pipelines and clinical trial biomarker discovery.
Given the genetic heterogeneity and adaptive plasticity of cancers like AML, tools such as CoPISA play an essential role in advancing precision medicine. By illuminating the molecular interplay of drug pairs, this method empowers clinicians and researchers to predict effective combinations, monitor treatment responses at a mechanistic level, and ultimately improve patient outcomes. The molecular granularity afforded by CoPISA could redefine how combination therapies are conceptualized, offering hope against cancers that have long resisted curative treatment.
As drug combinations continue to dominate the therapeutic landscape in oncology, the ability to mechanistically profile their effects at the proteome level represents a monumental step forward. CoPISA bridges a critical knowledge gap by transforming proteomics into a dynamic readout of drug synergy, enabling a deeper appreciation of how targeted combinations can exploit cancer cell dependencies. This pioneering work not only unveils novel biological principles like conjunctional targeting but also charts a course toward more rational, effective, and safer cancer treatments.
The publication of these findings in Nature Communications marks a milestone for proteomics-driven therapy design and signals exciting new directions for cancer research. The scientific community eagerly anticipates further developments from Tampere University and collaborators harnessing CoPISA to unlock the full potential of combinatorial drug therapies in oncology and beyond.
Subject of Research:
Mechanistic profiling of combinational drug therapies in acute myeloid leukemia through proteome-wide solubility and stability alterations.
Article Title:
Solubility based mechanistic profiling of combinatorial drug therapy
News Publication Date:
25-Mar-2026
Web References:
https://doi.org/10.1038/s41467-026-70394-3
References:
Jafari M. et al. (2026). Solubility based mechanistic profiling of combinatorial drug therapy. Nature Communications.
Keywords:
Acute myeloid leukemia, AML, combinational therapy, proteomics, CoPISA, protein solubility, protein stability, drug synergy, conjunctional targeting, LY3009120, sapanisertib, ruxolitinib, ulixertinib, precision medicine, drug resistance mechanisms.
