Therapeutic targeting of "undruggable" MYC

Pairwise analysis of plasma cell-free DNA before and after palliative second-line paclitaxel plus ramucirumab treatment in patients with metastatic gastric cancer

BACKGROUND

This study compared plasma cell-free DNA (cfDNA) and tumor tissue DNA (ttDNA) to explore the clinical applicability of cfDNA in patients with metastatic gastric cancer (mGC) receiving palliative second-line paclitaxel + ramucirumab treatment.

METHODS

Targeted sequencing of 106 genes was conducted using germline DNA and cfDNA at baseline (baseline-cfDNA) and progressive disease (PD-cfDNA). The results were compared with those of ttDNA-based cancer panel data.

RESULTS

Of 76 consecutive patients, 46 (27 males; median age 57.5 [range, 32-73] years) who had all three samples were included. Combined analysis of ttDNA and baseline-cfDNA revealed that TP53 (58.7%) was the most frequently mutated gene, followed by CDH1 (26.1%), KRAS (21.7%), and APC (13.0%). For these genes, the sensitivity and positive predictive value of baseline-cfDNA over ttDNA were 71.8% and 51.9%, respectively. When baseline-cfDNA and PD-cfDNA results were combined, 34 patients (73.9%) were found to have additional mutations compared with ttDNA results alone. PD-cfDNA analysis revealed 14 novel pathogenic mutations in ten patients (21.7%). At baseline, patients with a high circulating tumor DNA fraction concentration showed a significantly shorter progression-free survival (PFS) (P = 0.016) in univariable and multivariable analyses. High maximal variant allele frequency (VAF) (P = 0.022), high sum of VAF (P = 0.028), and high TP53 VAF (P = 0.022) were associated with worse PFS in univariable analysis.

CONCLUSIONS

Although cfDNA alone cannot replace ttDNA entirely, cfDNA analysis revealed additional mutations. Notably, PD-cfDNA analysis revealed novel pathogenic mutations that emerged during treatment. Moreover, the baseline circulating tumor DNA fraction concentration and VAF values were associated with longer PFS.

Targeting MYC: Multidimensional regulation and therapeutic strategies in oncology

MYC is dysregulated in approximately 70% of human cancers, strongly suggesting its essential function in cancer. MYC regulates many biological processes, such as cell cycle, metabolism, cellular senescence, apoptosis, angiogenesis, and immune escape. MYC plays a central role in carcinogenesis and is a key regulator of tumor development and drug resistance. Therefore, MYC is one of the most alluring therapeutic targets for developing cancer drugs. Although the search for direct inhibitors of MYC is challenging, MYC cannot simply be assumed to be undruggable. Targeting the MYC-MAX complex has been an effective method for directly targeting MYC. Alternatively, indirect targeting of MYC represents a more pragmatic therapeutic approach, mainly including inhibition of the transcriptional or translational processes of MYC, destabilization of the MYC protein, and blocking genes that are synthetically lethal with MYC overexpression. In this review, we delineate the multifaceted roles of MYC in cancer progression, highlighting a spectrum of therapeutic strategies and inhibitors for cancer therapy that target MYC, either directly or indirectly.

The synergy of TPL and selinexor in MLL-R acute myeloid leukemia via Rap1/Raf/MEK pathway-mediated MYC downregulation

MLL gene rearrangement recurrently occurs in acute myeloid leukemia (MLL-r AML), which is closely associated with chemotherapy insensitivity and unfavorable clinical outcomes. More importantly, there are limited therapeutic options for the management of patients with MLL-r AML, thus necessitating novel effective treatment strategies. In this study, we demonstrated that low doses of triptolide (LD TPL) and the XPO1 inhibitor selinexor exerted synergistic therapeutic effects on poor-outcome MLL-r AML in vitro, ex vivo and in vivo. Induction of mitochondrial outer membrane permeabilization (MOMP) and initiation of the mitochondrial apoptotic pathway were closely involved in the therapeutic synergy of LD TPL in combination with selinexor against MLL-r AML. Mechanistically, MYC downregulation mediated by the Rap1/Raf/MEK/ERK pathway rather than by PI3K/AKT signaling was implicated in the synergistic activity of the combined regimen. In addition, the induction of DNA damage also contributed to the synergistic effects of the combined regimen on MLL-r AML. In summary, our findings suggest that LD TPL in combination with selinexor might represent a promising therapeutic approach for the treatment of MLL-r AML. However, future clinical trials are mandatory to draw a decisive conclusion.

Myc family proteins: Molecular drivers of tumorigenesis and resistance in neuroendocrine tumors

Neuroendocrine cancers are a diverse and poorly understood collection of malignancies derived from neuroendocrine cells throughout the body. These cancers uniquely exhibit properties of both the nervous and endocrine systems. Only a limited number of genetic driver mutations have been identified in neuroendocrine cancers, however the mechanisms of how these genetic aberrations alter tumor biology remain elusive. Recent studies have implicated the MYC family of transcription factors as important oncogenic factors in neuroendocrine tumors. We take a systematic approach to understand the roles of the MYC family (c-MYC, n-MYC, l-MYC) in the tumorigenesis of neuroendocrine cancers of the lung, GI tract, pancreas, kidney, prostate, pediatric neuroblastoma, and adrenal glands. Reflecting the complexity of neuroendocrine cancers, we highlight the roles of the MYC family in deregulating the cell cycle and transcriptional networks, invoking cellular plasticity, affecting proliferation capacity, aiding in chromatin remodeling, angiogenesis, metabolic changes, and resistance mechanisms. Depicting the diversity of neuroendocrine cancers, we suggest new approaches in understanding the underlying tumorigenic processes of neuroendocrine cancers from the perspective of MYC.

Structure-based artificial intelligence-aided design of MYC-targeting degradation drugs for cancer therapy

The MYC protein is an oncoprotein that plays a crucial role in various cancers. Although its significance has been well recognized in research, the development of drugs targeting MYC remains relatively slow. In this study, we developed a novel MYC peptide inhibitor based on the MYC/MAX dimer structure, integrating artificial intelligence-assisted peptide drug design. Additionally, we introduced a chaperone-mediated autophagy signal to construct a MYC-targeted degradation drug, MYC-LYSO. By incorporating nano-selenium delivery, we further formulated an enhanced MYC degradation agent, Se-MYC-LYSO. Se-MYC-LYSO demonstrated potent efficacy in inducing MYC degradation, inhibiting tumor cell proliferation, and promoting apoptosis. Moreover, our findings indicate that the efficacy of Se-MYC-LYSO is dependent on the autophagy pathway. These results provide a novel strategy for targeting MYC in cancer therapy.

Utilizing aptamers in targeted protein degradation strategies for disease therapy

Targeted protein degradation (TPD) has emerged as a promising therapeutic strategy, offering the potential to reduce disease-causing proteins that have traditionally been challenging to target using conventional small molecules. Despite significant advances made with TPD technologies, challenges such as high molecular weight, difficulties in identifying suitable ligands, suboptimal absorption, and metabolic instability remain unresolved. Recently, aptamers - single-stranded DNA or RNA oligonucleotides known for their high specificity and affinity for protein targets - have introduced novel opportunities to expand the scope of TPD, a strategy now referred to as aptamer-based TPD. This approach has demonstrated considerable promise in treating various diseases, such as cancer and ocular disorders. For example, an aptamer-proteolysis-targeting chimera (PROTAC) conjugate (APC) improved tumor targeting and reduced toxicity in a breast cancer model, and a vascular endothelial growth factor-degrading (VED)-lysosome-targeting chimera (LYTAC) molecule effectively inhibited abnormal vascular growth in vascular retinal diseases. These examples highlight the practical relevance and potential in advancing drug discovery efforts. In this review we provide a comprehensive overview of the latest advances in aptamer-based TPD strategies, including proteolysis-targeting and lysosome-targeting chimeras, emphasizing their applications, potential therapeutic benefits, as well as the challenges that must be overcome to fully harness their clinical potential. © 2025 The Pathological Society of Great Britain and Ireland.

Interferon regulatory factor 1 contributes to metabolic dysfunction associated steatotic liver disease

AIMS

Non-alcoholic fatty liver disease (NAFLD) or metabolic dysfunction associated steatotic liver disease (MASLD), has reached epidemic levels in multiple regions worldwide and contributes to cirrhosis and hepatocellular carcinoma. We have previously reported that the CC motif chemokine ligand 11 (CCL11) is a key regulator of MASLD. Expression of interferon regulatory factor 1 (IRF1) can be up-regulated by CCL11 treatment in hepatocytes, the relevance of which is not clear. In the present study we investigated the role of IRF1 in NAFLD pathogenesis.

METHODS AND MATERIALS

MASLD was investigated in mice fed a high-fat high carbohydrate (HFHC) diet or in the genetically predisposed obese mice (db/db).

KEY FINDINGS

Hepatocytes from CCL11 knockout mice displayed a less severe MASLD phenotype, when treated with palmitic acid (PA), compared to wild type hepatocytes, which could be normalized by IRF1 over-expression. On the contrary, IRF1 knockdown in hepatocytes significantly down-regulated expression of pro-inflammatory mediators and dampened lipid accumulation induced by PA treatment. More importantly, IRF1 knockdown in hepatocytes led to amelioration of MASLD in mice. RNA-seq and CUT&Tag-seq identified pro-MASLD genes, including Osbpl3, Ddit4, and Ccl2, as potential targets for IRF1 in hepatocytes.

SIGNIFICANCE

Our data reveal a novel regulatory role of IRF1 in MASLD pathogenesis. Targeting IRF1 can be considered as a reasonable approach for MASLD intervention.

Effect of deubiquitinases in head and neck squamous cell carcinoma (Review)

HNSCC includes nasopharyngeal, laryngeal and oral cancers, and its pathogenesis is influenced by various factors. As an essential part of the ubiquitin (Ub)-proteasome system (UPS), deubiquitinating enzymes (DUBs) maintain the homeostasis of Ub molecules and influence the physiological functions of cells and disease processes by removing ubiquitinated proteins. Accumulating evidence has confirmed that the aberrant expression of DUBs is involved in cell proliferation, metastasis, and apoptosis during the development of HNSCC, with some acting as oncogenes and others as tumor-suppressor genes. In this review, the DUBs implicated in HNSCC were summarized and the mechanisms underlying abnormal DUBs expression in signaling pathways were discussed. In addition, given the important role of DUBs in tumorigenesis, recent studies were reviewed and agonists and inhibitors of DUBs were summarized to identify more effective therapeutic strategies.

Computer-Aided Drug Discovery for Undruggable Targets

Undruggable targets are those of therapeutical significance but challenging for conventional drug design approaches. Such targets often exhibit unique features, including highly dynamic structures, a lack of well-defined ligand-binding pockets, the presence of highly conserved active sites, and functional modulation by protein-protein interactions. Recent advances in computational simulations and artificial intelligence have revolutionized the drug design landscape, giving rise to innovative strategies for overcoming these obstacles. In this review, we highlight the latest progress in computational approaches for drug design against undruggable targets, present several successful case studies, and discuss remaining challenges and future directions. Special emphasis is placed on four primary target categories: intrinsically disordered proteins, protein allosteric regulation, protein-protein interactions, and protein degradation, along with discussion of emerging target types. We also examine how AI-driven methodologies have transformed the field, from applications in protein-ligand complex structure prediction and virtual screening to de novo ligand generation for undruggable targets. Integration of computational methods with experimental techniques is expected to bring further breakthroughs to overcome the hurdles of undruggable targets. As the field continues to evolve, these advancements hold great promise to expand the druggable space, offering new therapeutic opportunities for previously untreatable diseases.

LncRNA SLNCR phenocopies the E2F1 DNA binding site to promote melanoma progression

The long non-coding RNA SLNCR and the transcription factor E2F1 are known melanoma oncogenes. We show that SLNCR binds to E2F1 to promote the proliferation, invasion, and migration of melanoma cells from the bloodstream into the lungs. Blocking SLNCR-E2F1 complex formation without reducing the levels of either SLNCR or E2F1 prevents lung extravasation in mice. A 60-nt fragment of SLNCR contains two RNA analogs of the E2F1 DNA binding site (BS) in opposite orientations and can form a hairpin RNA that phenocopies the E2F1 DNA BS. Molecular dynamics (MD) simulations and biochemical experiments indicate that this fragment of SLNCR binds to the E2F1 DNA-binding domain more effectively than the E2F1 DNA BS. MD simulations predict higher affinity for DNA-E2F1 complex formation but faster kinetics and a greater number of RNA-amino acid contacts for the RNA-E2F1 complex, suggesting that RNA binding to E2F1 is more kinetically favorable.

Advancing Covalent Ligand and Drug Discovery beyond Cysteine

Targeting intractable proteins remains a key challenge in drug discovery, as these proteins often lack well-defined binding pockets or possess shallow surfaces not readily addressed by traditional drug design. Covalent chemistry has emerged as a powerful solution for accessing protein sites in difficult to ligand regions. By leveraging activity-based protein profiling (ABPP) and LC-MS/MS technologies, academic groups and industry have identified cysteine-reactive ligands that enable selective targeting of challenging protein sites to modulate previously inaccessible biological pathways. Cysteines within a protein are rare, however, and developing covalent ligands that target additional residues hold great promise for further expanding the ligandable proteome. This review highlights recent advancements in targeting amino acids beyond cysteine binding with an emphasis on tyrosine- and lysine-directed covalent ligands and their applications in chemical biology and therapeutic development. We outline the process of developing covalent ligands using chemical proteomic methodology, highlighting recent successful examples and discuss considerations for future expansion to additional amino acid sites on proteins.

MYC plus class IIa HDAC inhibition drives mitochondrial dysfunction in non-small cell lung cancer

Despite much progress in targeting the MYC oncoprotein, combination treatment strategies are needed to exploit this molecular vulnerability. To this end, we interrogated transcriptome data from cancer cell lines treated with MYC inhibitors and identified HDAC5 and HDAC9, both class IIa histone deacetylases (HDACs), as potential therapeutic targets. Notably, these therapeutically actionable HDAC isoforms are known augmenters of several hallmarks of cancer. Dual targeting of MYC and class IIa HDACs induces a significant reduction in viability for non-small cell lung cancer (NSCLC) cell lines with high MYC and mitochondrial activity. Additionally, combination treatment induces a robust MYC suppression with mitochondrial reactive oxygen species (ROS) elevation, which has a causal relationship with therapeutic efficacy. Confirmation of in vivo efficacy was pursued in several animal models, with subsequent molecular-correlate derivation confirming the importance of MYC depletion and mitochondrial dysfunction in drug efficacy. Ultimately, we define a therapeutic approach combining MYC- and class IIa HDAC-inhibition to potentiate anti-tumor efficacy in NSCLC.

METTL13 is essential for the survival of acute myeloid leukemia cells by regulating MYC

Recently, some methyltransferase-like (METTL) proteins have been found to play crucial roles in the development of acute myeloid leukemia (AML) through mediating RNA modifications, such as METTL3/14/16 mediated N6-methyladenosine (m6A) and METTL1 mediated N7-methylguanosine (m7G). However, the roles of other METTL proteins in AML progression remain unknown. Here, we examined the expression levels of all METTL members in AML samples and showed that METTL13 was increased in AML and positively correlated with poor prognosis. Moreover, METTL13 deficiency impaired AML cell proliferation capability in vitro, improved the survival of AML cell line xenograft immune-deficient mice, and reduced tumor infiltration in vivo. Mechanistically, MYC was downregulated after METTL13 knockdown and forced expression of MYC rescued the cell proliferation defect in METTL13-deficient AML cells. Our findings uncover the critical role of METTL13 in the survival of AML cells and identify MYC as a potential downstream target of METTL13. This work highlights METTL13 as a promising candidate target for AML therapy.

MLCK inhibition induces synthetic lethality in MYC-driven cancer

The dysregulation of MYC is widely implicated in human cancers, yet MYC remains an 'undruggable' target. Here, we performed a CRISPR-based loss-of-function screen focusing on kinases, most of which are 'druggable,' to identify genes essential for MYChigh but not MYClow cells. Using an isogenic pair of nonmalignant cells with and without ectopic MYC expression, we uncovered novel MYC synthetic lethal (MYC-SL) interactions, including Myosin Light-Chain Kinase (MLCK) as the most potent MYC-SL target. Inhibition of MLCK induced MYC-dependent cell death, significantly suppressing tumor growth in MYC-driven xenografts, the ApcMin/+ mouse model of colon cancer, and the MYC-transgenic hepatocellular carcinoma (HCC) model, without apparent toxicity. This cell death is attributed to selective DNA damage and p53-mediated apoptosis. Mechanistically, MYC activation promotes nuclear accumulation of myosin II at stalled replication forks, where it resolves replication stress and supports survival. MLCK inhibition disrupts myosin II activity, leading to unresolved replication stress, DNA damage, and activation of the p53-mediated apoptosis pathway. Our findings suggest that targeting MLCK offers a promising therapeutic strategy for MYC-driven cancers.

MYC alterations in multiple myeloma: Genetic insights and prognostic impact

Multiple myeloma (MM) is a hematologic malignancy with high genetic complexity. The genetic alterations that drive MM have classically been classified as primary abnormalities, including IGH translocations and hyperdiploidy, and secondary abnormalities, mainly composed of 1q gains, 17p deletions and MYC rearrangements. Dysregulation of the MYC oncogene has been proposed as a key factor in disease progression from monoclonal gammopathy of undetermined significance (MGUS), smoldering MM and overt MM. MYC, a multifunctional transcription factor, is frequently activated in MM through various mechanisms, including translocations, amplifications, and overexpression, thereby contributing to the growth and survival of malignant plasma cells. The role of MYC abnormalities in the prognosis of MM remains controversial and continues to be overlooked in current prognostic indices for MM. The different methodologies used to detect MYC lesions may hinder the interpretation of the apparently contradictory results between studies analyzing the impact of these alterations on the survival of MM patients. On the other hand, the mouse models that best mimic the characteristics of human MM are those driven by MYC. In this review, we provide an overview of the MYC alterations described in MM, indicating the methodologies used to detect them and discussing their influence on patient prognosis. We also summarize the main characteristics of the genetically engineered mouse models driven by MYC. Finally, we assess the therapeutic potential of MYC inhibition in MM and the strategies currently approved for clinic use.

Circaea mollis Siebold & Zucc. Induces Apoptosis in Colorectal Cancer Cells by Inhibiting c-Myc Through the Mediation of RPL5

Colorectal cancer remains a significant global health concern. In this study, we investigated the anticancer potential of Circaea mollis Siebold & Zucc. (CS&Z), a traditional medicinal plant known for its anti-inflammatory, anti-arthritic, and antioxidant properties, in the treatment of colorectal cancer. We found that CS&Z induces apoptosis and G1/S phase cell cycle arrest in colorectal cancer cells, primarily through the suppression of the proto-oncogene c-Myc. Specifically, the depletion of RPL5, a ribosomal protein associated with c-Myc regulation, reversed the suppression of c-Myc by CS&Z. Additionally, when co-administered with the standard chemotherapeutic agents doxorubicin and 5-fluorouracil, CS&Z demonstrated synergistic effects, thereby further emphasizing its potential efficacy as a therapeutic option for the treatment of colorectal cancer. Moreover, the constituents of CS&Z, detected through liquid chromatography-mass spectrometry analysis, reportedly exhibit anticancer activities. Taken together, our findings suggest that CS&Z holds promise as a natural product capable of modulating oncogenic signaling in colorectal cancer and may serve as a complementary agent in future therapeutic strategies.

Unlocking the Radiosensitizing Potential of MYC Inhibition in Neuroendocrine Malignancies

The MYC family of transcription factors-comprising c-MYC, N-MYC, and L-MYC-plays a pivotal role in oncogenesis, driving cancer progression and resistance to therapy. While MYC proteins have long been considered challenging drug targets due to their intricate structures, recent advances have led to the development of promising inhibitors. This review explores the role of MYC overexpression in promoting radiation therapy resistance in aggressive neuroendocrine malignancies through multiple mechanisms, including increased tumor cell invasion, enhanced DNA damage repair and oxidative stress management, prosurvival autophagy, survival of circulating tumor cells, angiogenesis, awakening from dormancy, and modulation of chronic inflammation and host immunity. Paradoxically, MYC overexpression can also enhance radiosensitivity in certain cancer cells by driving proapoptotic pathways, such as reactive oxygen species-induced DNA damage that overwhelms cellular repair mechanisms, ultimately leading to cell death. Additionally, we provide a comprehensive summary of direct MYC inhibitors, detailing their current stage of preclinical and clinical development as novel anticancer therapeutics. This review highlights the role of MYC in cancer metastasis and radiation therapy resistance while examining the potential of MYC inhibitors as radiosensitizers in adult and pediatric neuroendocrine malignancies, including small cell lung cancer, large cell neuroendocrine lung cancer, Merkel cell carcinoma, neuroendocrine-differentiated prostate cancer, neuroblastoma, central nervous system embryonal tumors, and medulloblastoma.

NCOA5 induces sorafenib resistance in hepatocellular carcinoma by inhibiting ferroptosis

NCOA5 has been identified as a crucial factor in the progression of hepatocellular carcinoma (HCC). This study investigates the expression of NCOA5 in HCC, revealing its significant overexpression in tumor tissues compared to healthy liver tissues, as evidenced by analysis of the TCGA dataset and RT-qPCR in patient samples. Higher NCOA5 levels correlate with poor overall survival, highlighting its role as a prognostic indicator. Furthermore, our findings suggest that elevated NCOA5 is associated with resistance to sorafenib, a common chemotherapeutic agent for HCC, as shown through analysis of publicly available datasets and the establishment of sorafenib-resistant HCC cell lines. Mechanistically, NCOA5 appears to inhibit ferroptosis in HCC cells by modulating glutathione peroxidase 4 (GPX4) levels. Knockdown of NCOA5 sensitizes resistant cell lines to sorafenib and induces ferroptosis by decreasing GPX4 expression. Additionally, NCOA5 regulation of GPX4 is mediated through the transcription factor MYC. In vivo studies further validate that targeting NCOA5 enhances the efficacy of sorafenib in resistant HCC models by promoting ferroptosis. Collectively, these findings underscore the potential of NCOA5 as a therapeutic target to overcome drug resistance in HCC, providing insights into its role in modulating treatment responses and patient prognosis.

Targeting Myc through BET-PROTAC elicits potent anti-lymphoma activity in diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) presents a great challenge in the clinic due to its poor prognosis. Prior research has identified c-Myc as a promising therapeutic target in DLBCL; however, direct targeting of c-Myc protein has proven challenging. The bromodomain and extraterminal (BET) protein family, which acts as transcriptional and epigenetic regulators, plays a crucial role in super-enhancer organization and transcriptional regulation of oncogenic drivers like c-Myc, offering an alternative approach. Recently developed BET proteolysis targeting chimera (PROTAC) compounds can rapidly and effectively degrade BET proteins and potentially offer a more durable effect than traditional BET inhibitors. In this work, we compared the anti-tumor activity of a BET PROTAC, ARV-825, with a BET inhibitor, JQ1, in DLBCL. Cell proliferation was assessed by CCK-8 assay, apoptosis was evaluated by Annexin V/PI staining, and the cell cycle was analyzed by staining DNA with propidium iodide (PI). Western blotting was used to determine the expression levels of BET family proteins and its downstream regulatory gene c-Myc, and the in vivo SCID mouse model implanted with SU-DHL-4 cells was used to analyze the in vivo drug efficacy. Our results showed that ARV-825 was superior to JQ1 in inhibiting DLBCL cell proliferation, inducing apoptosis, promoting cell cycle arrest, and prolonging survival. Notably, ARV-825 was more effective at downregulating c-Myc and BET protein levels than JQ1 in both in vitro and in vivo experiments. These evidences suggest that BET-PROTACs may offer a promising novel strategy for the clinical treatment of DLBCL.

PDCD11 Stabilizes C-MYC Oncoprotein by Hindering C-MYC-SKP2 Negative Feedback Loop to Facilitate Progression of p53-Mutant Breast and Colon Malignancies

C-MYC is a proto-oncoprotein whose dysregulation triggers tumorigenesis and tumor progression in ≈70% of cancer cases. It is presently demonstrated that aberrantly upregulated MYC is caused by the overexpressed and "extra-nucleolar" PDCD11 in p53-mutant breast and colon cancer cells, which is highly correlated to tumor progression, metastasis, and recurrence. In the nucleoplasm, PDCD11 binds to the TAD of C-MYC to prevent SKP2, a transcriptional target of C-MYC as well as one of the major E3 ligase components targeting C-MYC, from interacting with and ubiquitinating C-MYC in feedback. The ensuing stabilized C-MYC activates downstream signaling to facilitate the cellular G1/S transition, proliferation, and migration. PDCD11 silencing restores SKP2-mediated C-MYC degradation, thereby remarkably suppressing tumor growth and metastasis in nude mice. These findings highlight PDCD11 as a novel C-MYC partner and thereby offer a potential therapeutic rationale to challenge PDCD11-mediated "pro-stabilization" effect on C-MYC, a widely considered "undruggable" target, to combat C-MYC-driven malignancies with p53 mutation.

Conformational modulation of intrinsically disordered transactivation domains for cancer therapy

Intrinsically disordered proteins are implicated in many diseases, but their overrepresentation among transcription factors, whose deregulation can cause disproportionate expression of oncogenes, suggests an important role in cancer. Targeting disordered transcription factors for therapy is considered challenging, as they undergo dynamic transitions and exist as an ensemble of interconverting states. This enables them to interact with multiple downstream partners, often through their transactivation domains (TADs) by the mechanisms of conformational selection, folding-upon-binding, or formation of "fuzzy" complexes. The TAD interfaces, despite falling outside of what is considered "classical" binding pockets, can be conformationally modulated to interfere with their target recruitment and hence represent potentially druggable sites. Here, we discuss the structure-activity relationship of TADs from p53, c-MYC, and the androgen receptor, and the progresses made in modulating their interactions with small molecules. These recent advances highlight the potential of targeting these so far "undruggable" proteins for cancer therapy.

Rethinking MYC inhibition: a multi-dimensional approach to overcome cancer's master regulator

MYC, a master regulator in oncogenesis, has long been deemed "undruggable" due to its intrinsically disordered structure. However, recent advances are overturning this view, with direct inhibitors like Omomyc (OMO-103) and PROTAC-based degraders such as WBC100 showing promising clinical progress. Complementary strategies-including BET and CDK9 inhibitors, RNA-based therapeutics, nanobodies, and engineered proteases-are expanding the therapeutic landscape. Despite challenges in specificity, toxicity, and delivery, these innovations underscore MYC's emerging druggability. Moreover, combination therapies integrating MYC inhibitors with chemotherapy, radiotherapy, or immunotherapy demonstrate synergistic potential. This article advocates for a multi-dimensional, biomarker-guided approach to MYC targeting, emphasizing rational drug combinations and continued innovation to overcome resistance and improve outcomes in MYC-driven cancers.

MYCN and KAT2A form a feedforward loop to drive an oncogenic transcriptional program in neuroblastoma

The oncoprotein MYCN drives malignancy in various cancer types, including neuroblastoma (NB). However, our understanding of the mechanisms underlying its transcriptional activity and oncogenic function, as well as effective strategies to target it, remains limited. We discovered that MYCN interacts with the transcriptional coactivator KAT2A, and this interaction significantly contributes to MYCN's activity in NB. Our genome-wide analyses indicate MYCN recruits KAT2A to bind to DNA, thereby transcriptionally regulating genes associated with ribosome biogenesis and RNA processing. Moreover, we identified that MYCN directly activates KAT2A transcription, while KAT2A acetylates MYCN, increasing MYCN protein stability. Consequently, MYCN and KAT2A establish a feedforward loop that effectively regulates global gene expression, governing the malignant NB phenotype. Treatment of NB cells with a KAT2A Proteolysis Targeting Chimera (PROTAC) degrader reduces MYCN protein levels, antagonizes MYCN-mediated gene transcription regulation and suppresses cell proliferation. This study highlights the potential of transcriptional cofactors as viable targets for developing anti-MYCN therapies.

Dibromo-Edaravone Induces Anti-Erythroleukemia Effects via the JAK2-STAT3 Signaling Pathway

Acute erythroid leukemia (AEL) is a rare and aggressive hematological malignancy managed with chemotherapy, targeted therapies, and stem cell transplantation. However, these treatments often suffer from limitations such as refractoriness, high toxicity, recurrence, and drug resistance, underscoring the urgent need for novel therapeutic approaches. Dibromo-edaravone (D-EDA) is a synthetic derivative of edaravone (EDA) with unreported anti-leukemic properties. In this study, D-EDA demonstrated potent cytotoxicity against HEL cells with an IC50 value of 8.17 ± 0.43 μM using an MTT assay. Morphological analysis via inverted microscopy revealed reductions in cell number and signs of cellular crumpling and fragmentation. Flow cytometry analysis, Hoechst 33258 staining, Giemsa staining, a JC-1 assay, and a reactive oxygen species (ROS) assay showed that D-EDA induced apoptosis in HEL cells. Furthermore, D-EDA induced S-phase cell cycle arrest. Western blot analysis showed significant upregulation of key apoptosis-related proteins, including cleaved caspase-9, cleaved caspase-3, and cleaved poly ADP-ribose polymerase (PARP), alongside a reduction in Bcl-2 expression. Additionally, oncogenic markers such as c-Myc, CyclinA2, and CDK2 were downregulated, while the cell cycle inhibitor p21 was upregulated. Mechanistic studies involving molecular docking, a cellular thermal shift assay (CETSA), the caspase inhibitor Z-VAD-FMK, JAK2 inhibitor Ruxolitinib, and STAT3 inhibitor Stattic revealed that D-EDA activates the caspase cascade and inhibits the JAK2-STAT3 signaling pathway in HEL cells. In vivo, D-EDA improved spleen structure, increased the hemolysis ratio, and extended survival in a mouse model of acute erythroleukemia. In conclusion, D-EDA induces apoptosis via the caspase cascade and JAK2-STAT3 signaling pathway, demonstrating significant anti-leukemia effects in vitro and in vivo. Thus, D-EDA may be developed as a potential therapeutic agent for acute erythroleukemia.

MYC-Targeting PROTACs Lead to Bimodal Degradation and N-Terminal Truncation

MYC is a master regulatory transcription factor whose sustained dysregulation promotes the initiation and maintenance of numerous cancers. While MYC is a regarded as a potenial therapeutic target in cancer, its intrinsically disordered structure has proven to be a formidable barrier toward the development of highly effective small molecule inhibitors. We rationalized that proteolysis targeting chimeras (PROTACs), which might accomplish the targeted degradation of MYC, would achieve more potent cell killing in MYC-driven cancer cells than reversible inhibitors. PROTACs are bifunctional small molecules designed to produce a ternary complex between a target protein and an E3 ligase leading the target's ubiquitination and degradation by the 26S proteasome. We generated PROTAC MTP3 based on modifications of the previously reported MYC-targeting compound KJ-Pyr-9. We found that MTP3 depletes endogenous full-length MYC proteins and uniquely induces increasing levels of a functional, N-terminally truncated MYC species, tMYC. Furthermore, MTP3 perturbs cellular MYC levels in favor of a tMYC-dominated state whose gene regulatory landscape is not significantly altered compared to that of wild type MYC. Moreover, although it lacks ∼10 kDa of MYC's N-terminal transactivation domain, tMYC is sufficient to maintain an oncogenic proliferative state. Our results highlight the complexities of proximity-inducing compounds against highly regulated and conformationally dynamic protein targets such as MYC and indicate that PROTACs can induce alternative outcomes beyond target protein degradation.

AZIN1-dependent polyamine synthesis accelerates tumor cell cycle progression and impairs effector T-cell function in osteosarcoma

Osteosarcoma, the most prevalent malignant bone tumor among adolescents, frequently exhibits limited responsiveness to immunotherapy, a challenge attributed to poorly understood underlying mechanisms. Here, we identify enhanced polyamine biosynthesis as a key driver of osteosarcoma progression and immunotherapy resistance. We show that osteosarcoma cell proliferation and tumor growth rely on polyamine availability and that disruption of polyamine synthesis significantly boosts the cytotoxic efficacy of TCR-engineered T cells against osteosarcoma cells. Mechanistically, we reveal that the knockdown of antizyme inhibitor 1 (AZIN1) or suppression of polyamine production reduces MYC expression, leading to diminished tumor cell viability via the downregulation of cell cycle-related genes. Furthermore, reduced MYC levels are associated with changes in the expression of immunomodulatory cytokines and human leukocyte antigen molecules, pointing to a potential link with enhanced T-cell-mediated cytotoxicity. Collectively, our findings establish a pivotal role for the AZIN1-polyamine axis in osteosarcoma proliferation and immune evasion, and support the development of novel immunotherapeutic strategies targeting polyamine biosynthesis to combat this aggressive cancer.

Linker Design Principles for the Precision Targeting of Oncogenic G-Quadruplex DNA with G4-Ligand-Conjugated Oligonucleotides

G-quadruplex (G4) DNA structures are noncanonical secondary structures found in key regulatory regions of the genome, including oncogenic promoters and telomeres. Small molecules, known as G4 ligands, capable of stabilizing G4s hold promise as chemical probes and therapeutic agents. Nevertheless, achieving precise specificity for individual G4 structures within the human genome remains a significant challenge. To address this, we expand upon G4-ligand-conjugated oligonucleotides (GL-Os), a modular platform combining the stabilizing properties of G4-ligands with the sequence specificity of guide DNA oligonucleotides. Central to this strategy is the linker that bridges the G4 ligand and the guide oligonucleotide. In this study, we develop multiple conjugation strategies for the GL-Os that enabled a systematic investigation of the linker in both chemical composition and length, enabling a thorough assessment of their impact on targeting oncogenic G4 DNA. Biophysical, biochemical, and computational evaluations revealed GL-Os with optimized linkers that exhibited enhanced binding to target G4s, even under thermal or structural stress. Notably, longer linkers broadened the range of targetable sequences without introducing steric hindrance, thereby enhancing the platform's applicability across diverse genomic contexts. These findings establish GL-Os as a robust and versatile tool for the selective targeting of individual G4s. By facilitating precise investigations of G4 biology, this work provides a foundation for advancing G4-targeted therapeutic strategies and exploring their role in disease contexts.

Exploiting replication stress for synthetic lethality in MYC-driven cancers

The oncoprotein MYC, overexpressed in more than 70% of human cancers, plays a pivotal role in regulating gene transcription and has long been recognized as a promising target for cancer therapy. However, no MYC-targeted drug has been approved for clinical use, largely due to the lack of a well-defined druggable domain and its nuclear localization. MYC-overexpressing cancer cells exhibit increased replication stress, driven by factors such as elevated replication origin firing, nucleotide depletion, replication-transcription conflicts, and heightened reactive oxygen species (ROS) production. Simultaneously, MYC activates compensatory mechanisms, including enhanced DNA repair, checkpoint-mediated cell cycle regulation, and metabolic reprogramming, to mitigate this stress and support cell survival. Interfering with these compensatory pathways exacerbates replication stress, leading to synthetic lethality in MYC-driven cancer cells. In this review, we summarize recent advances in leveraging replication stress to achieve synthetic lethality in MYC-driven cancers. Furthermore, we discuss current strategies targeting replication stress, highlighting new opportunities for the development of therapies against MYC-driven malignancies.

Targeting endothelial MYC using siRNA or miR-218 nanoparticles sensitizes chemo- and immuno-therapies by recapitulating the Notch activation-induced tumor vessel normalization

Background: The chaotic, over-activated tumor vasculature promotes tumor growth and erodes most current therapies. Although Notch activation critically regulates angiogenesis, the broad roles of Notch has dampened its druggability. Methods: Gene-modified mice with a Cdh5-CreERT transgene were employed to activate/block Notch signaling in endothelial cells (ECs). Multiple transcriptome analyses were conducted to compare gene expression profiles. qRT-PCR and western blotting were used to determine gene expression level. Immunofluorescence and flow cytometry were used to observe morphological alterations and immune microenvironment in tumors. Nanoparticles (PEI-PEG-cRGD) were used to deliver siRNA into tumor ECs (TECs) in vivo. Results: Genetic Notch activation or blockade in TECs normalizes or deteriorates tumor vessels, respectively. Single-cell RNA sequencing showed that Notch activation selectively reduced the proliferating TEC subset, which accounted for about 30% of TECs and gave rise to other TEC subsets. Notch activation or blockade downregulated or upregulated MYC, respectively. MYC overexpression canceled Notch activation-induced proliferation arrest of TECs in vitro, and a MYC inhibitor normalized tumor vessels in RBPj deficient mice, suggesting that MYC is the authentic Notch target in normalizing tumor vessels. Nanoparticles encapsulated with MYC siRNA (EC-siMYC) or miR-218 (EC-miR-218), a Notch-downstream miRNA suppressing MYC, were able to mitigate Notch inhibition-induced tumor vessel defects. Combination of cisplatin with MYC blockade exhibited improved therapeutic effects. Moreover, MYC blockade promoted T cell infiltration and enhanced anti-PD1 immunotherapy. Conclusions: Together, our data have demonstrated that Notch activation normalizes tumor vessels by repressing the proliferating TEC subset via MYC, and targeting endothelial MYC using nanoparticles bearing siRNA or miRNA is an efficient strategy for tumor anti-angiogenic therapy.

Senkyunolide A interrupts TRAF6-HDAC3 interaction to epigenetically suppress c-MYC and attenuate cholestatic liver injury

Introduction Cholestatic liver diseases are highly prevalent and lack effective treatment, ultimately progressing to end-stage liver diseases. Our recent study indicates that the interplay between c-MYC and lncRNA H19 exacerbates the ductular reaction during cholestasis.

OBJECTIVE

This study aims to unveil the underlying mechanisms of the protective effects of senkyunolide A (SenA) on cholangiocyte overproliferation in cholestatic liver diseases.

METHODS

Through comprehensive characterization using RNA sequencing, CHIP analysis, protein truncation, amino acid mutation or deletion, and the development of SenA derivatives, we explored the effects and mechanisms of SenA in vivo in bile duct ligation mice and in vitro in primary cholangiocytes.

RESULTS

We demonstrated that SenA effectively mitigates cholangiocyte hyperproliferation by epigenetically suppressing c-MYC expression and disrupting the downstream H19, Let-7a and Lin28a. Mechanically, we identified a potential interaction between the carbonyl group in SenA and Arg483 in TRAF6, disrupting the TRAF6-HDAC3 complex. This dissociation facilitates the binding of HDAC3 to the MYC promoter region, resulting in enhanced histone deacetylation and transcriptional suppression.

CONCLUSION

We highlight the therapeutic potential of SenA in cholestatic liver diseases by elucidating its role in epigenetic regulation.

It's all downstream from here: RTK/Raf/MEK/ERK pathway resistance mechanisms in glioblastoma

BACKGROUND

The receptor tyrosine kinase (RTK)/Ras/Raf/MEK/ERK signaling pathway is one of the most tumorigenic pathways in cancer, with its hyperactivation strongly linked to the aggressive nature of glioblastoma (GBM). Although extensive research has focused on developing therapeutics targeting this pathway, clinical success remains elusive due to the emergence of resistance mechanisms.

OBJECTIVE

This review investigates how inhibition of the RTK/Ras/Raf/MEK/ERK pathway alters transcription factors, contributing to acquired resistance mechanisms in GBM. It also highlights the critical role of transcription factor dysregulation in therapeutic resistance.

METHODS & RESULTS

Findings from key studies on the RTK/Ras/Raf/MEK/ERK pathway in GBM were synthesized to explore the role of transcription factor dysregulation in resistance to targeted therapies, radiation, and chemotherapy. The review highlights that transcription factors undergo significant dysregulation following RTK/Ras/Raf/MEK/ERK pathway inhibition, contributing to therapeutic resistance.

CONCLUSION

Transcription factors are promising targets for overcoming treatment resistance in GBM, with cotreatment strategies combining RTK/Ras/Raf/MEK/ERK pathway inhibitors and transcription factor-targeted therapies presenting a novel approach. Despite the challenges of targeting complex structures and interactions, advancements in drug development and precision technologies hold great potential. Continued research is essential to refine these strategies and improve outcomes for GBM and other aggressive cancers.

PLEKHA4 knockdown induces apoptosis in melanoma cells through the MAPK and β‑catenin signaling pathways

Malignant melanoma (MM) is a highly aggressive subtype of skin cancer characterized by a poor prognosis, particularly in the advanced stages. Despite advancements in targeted therapy and immunotherapy, the survival rates for MM remain low, underscoring the need for new therapeutic targets. Pleckstrin homology domain‑containing family A member 4 (PLEKHA4), which has regulatory functions in pivotal cellular processes, has emerged as a potential target in melanoma. The present study aimed to investigate the role of PLEKHA4 in melanoma progression, focusing on its influence on the MAPK and Wnt/β‑catenin signaling pathways. Bioinformatics analysis revealed that PLEKHA4 was upregulated in melanoma tissues, whereas PLEKHA4 knockdown in melanoma cell lines (A375 and A2058) significantly inhibited cell proliferation and migration, enhanced apoptosis and inhibited tumor growth in vivo. Mechanistic studies demonstrated that PLEKHA4 may exert its effects by modulating the MAPK signaling pathway through interactions with key proteins, including ERK, JNK and MEK. Additionally, PLEKHA4 was shown to impact apoptosis by regulating caspase‑3, COX2 and p65. Additionally, β‑catenin nuclear translocation was affected via the Wnt pathway. Moreover, PLEKHA4 knockdown reduced cMyc ubiquitination, consequently promoting its degradation. The present findings suggested that PLEKHA4 could promote melanoma cell proliferation by regulating both the MAPK and Wnt/β‑catenin pathways, thereby proposing PLEKHA4 as a promising therapeutic target for MM. Further studies are warranted to elucidate the mechanisms underlying PLEKHA4‑mediated modulation of cMyc ubiquitination.

Genomic Insights Into Early Relapsed Breast Cancer: Prognostic Challenges and Mutation Landscape

Purpose

Early relapsed breast cancer, characterized by recurrence within two years post-surgery, often results from drug resistance and rapid progression. The clinicopathological, prognostic and molecular features of these patients still await exploration.

Methods

In this study, 43 patients with early relapsed breast cancer were included as well as 42 advanced breast cancer patients who experienced a recurrence after two years since surgery as the control group. Clinicopathological factors and prognosis were compared among the two groups, and tumor tissue from 27 available early relapsed patients was subjected to genetic sequencing.

Results

Compared with the control group, early relapsed group exhibited more aggressive malignant biological characteristics, shorter median overall survival (27.8 vs 49.8 months, P=0.005) and lower objective response rate for the first line treatment (42.90% vs 86.8%, P<0.001). Genetic sequencing of 27 early relapsed breast cancer demonstrated with TP53 (52%), PIK3CA (22%), and MLL3 (19%) as the top three frequently mutated genes, suggesting potential therapeutic targets for personalized treatment strategies.

Conclusion

Early relapsed breast cancer patients demonstrated poor prognosis and treatment response, indicating a reagent need of effective treatment combination for disease control. Genetic sequencing may identify potential therapeutic targets, providing new therapeutic opportunities for such patients. These findings underline the urgent need for personalized therapeutic strategies informed by genetic profiling to improve outcomes for early-relapsed breast cancer patients.

A dual-mode immunosensor for detection of oncoprotein c-Myc via indirect competition using trimetallic nanocomposite as an excellent label

BACKGROUND

The expression of oncoprotein c-Myc (OPc-Myc) in blood is closely related to the occurrence and development of various tumors. Common detection methods have the disadvantages of complicated procedures, expensive instruments, or low sensitivity. Currently, several single-mode immunosensors have been developed to detect OPc-Myc and overcome the above shortcomings. However, they are susceptible to the interference of the sensing interface and the external environment, which may lead to false-positive or false-negative results. Therefore, sensitive and accurate assessment of OPc-Myc levels in the blood is very important for the early diagnosis and monitoring of tumors.

RESULTS

A novel electrochemiluminescence (ECL)-electrochemical (EC) dual-mode immunosensor was developed for the sensitive detection of trace OPc-Myc. Gold nanoparticles-magnetic reduced graphene oxide (AuMrGO), with a large surface area and conductivity, were stably fixed on a magnetic glassy carbon electrode and utilized as the immobilization platform. Ruthenium(II)tris(bipyridine) (Ru) doped Au, Ag, and Pd trimetallic nanocomposite (Tri-Ru) with excellent ECL and EC properties was synthesized by mechanical alloying method and used as the bifunctional signaling label. Further, combined with the trace detection advantages of indirect competition, the convenient and sensitive dual-mode detection of OPc-Myc was realized. The results showed a strong linear relationship for concentrations from 10 pg L-1 to 0.1 μg L-1 in ECL mode and from 0.1 ng L-1 to 1 μg L-1 in EC mode, with limits of detection (LOD) of 4.9 pg L-1 and 30 pg L-1, respectively. The assay performed good analytical performances and clinical practicability in lymphoma patients' blood samples.

SIGNIFICANCE

This is the first detection of OPc-Myc using an ECL immunosensor, and it is also the first attempt to use a dual-mode detection strategy for OPc-Myc. The strategy could be used for sensing and detecting other proteomic tumor markers and established a promising platform for early auxiliary diagnosis and monitoring of cancers.

Mesothelioma cell heterogeneity identified by single cell RNA sequencing

Mesothelioma cell heterogeneity encompasses diverse morphological and molecular characteristics observed within tumors, significantly impacting disease progression, treatment outcomes, and the development of targeted therapies. This heterogeneity has long posed challenges for accurate diagnosis and effective treatment, but understanding its complexities offers the potential for novel diagnostic modalities and therapeutic interventions. This study employed single-cell RNA sequencing (scRNA-seq) to investigate mesothelioma cell heterogeneity from various sources, including cell culture (CC), peritoneal lavage (Lav) from the tumor microenvironment, and circulating tumor cells (CTC) in murine models. Gene set enrichment analysis was used to identify distinct gene signatures for each subpopulation. The results revealed unique characteristics for mesothelioma cells depending on their origin. In the CC group, up-regulated genes were primarily involved in tumor cell cycle control, proliferation, and apoptosis. In the CTC group, up-regulated genes were associated with cancer cell stemness. The Lav group showed up-regulated genes facilitating interactions between tumor cells and the microenvironment, such as epithelial-mesenchymal transition and immune responses mediated by IFN-α and IFN-γ. Some pathways were shared among all tumor cells, suggesting the potential for transitioning between functional states under specific conditions. This may be the first study to explore circulating mesothelioma cell heterogeneity using scRNA-seq. The distinct gene signatures identified in each mesothelioma cell subpopulation likely play critical roles in tumor initiation and progression, offering potential novel targets for therapeutic intervention. These findings could help inform the development of more effective, personalized treatments for mesothelioma, ultimately improving patient outcomes.

Heterobifunctional proteomimetic polymers for targeted protein degradation

The burgeoning field of targeted protein degradation (TPD) has opened new avenues for modulating the activity of previously undruggable proteins of interest. To date, TPD has been dominated by small molecules containing separate linked domains for protein engagement and recruitment of cellular degradation machinery. The process of identifying active compounds has required tedious optimization and has been successful largely against a limited set of targets with well-defined, suitable docking pockets. Here we present a polymer chemistry approach termed the HYbrid DegRAding Copolymer (HYDRAC) to overcome standing challenges associated with the development of TPD. These copolymers densely display either peptide-based or small molecule-derived degradation inducers and target-binding peptide sequences for the selective degradation of disease-associated proteins. HYDRACs are synthesized in a facile manner, are modular in design, and are highly selective. Using the intrinsically disordered transcription factor MYC as an initial proof-of-concept, difficult to drug protein target, HYDRACs containing a MYC-inhibitory peptide copolymerized with a validated degron, showed robust and selective degradation of the target protein. Treatment of tumor-bearing mice with MYC-targeted HYDRACs showed decreased cell proliferation and increased tumor apoptosis, leading to significantly suppressed tumor growth in vivo . The versatility of the platform was demonstrated by substituting the degron for recruiters of three different E3 ligases (VHL, KEAP1, and CRBN), which all maintained MYC degradation. To demonstrate generalizability, HYDRACs were further designed against a second elusive target of clinical interest, KRAS, by employing a consensus RAS binding motif. RAS-targeted HYDRACs showed degradation in two cell lines harboring separate KRAS alleles, suggesting potential pan-KRAS activity. We envision the HYDRAC platform as a generalizable approach to developing degraders of proteins of interest, greatly expanding the therapeutic armamentarium for TPD.

Molecular and immune landscape of hepatocellular carcinoma to guide therapeutic decision-making

Liver cancer, primarily HCC, exhibits highly heterogeneous histological and molecular aberrations across tumors and within individual tumor nodules. Such intertumor and intratumor heterogeneities may lead to diversity in the natural history of disease progression and various clinical disparities across the patients. Recently developed multimodality, single-cell, and spatial omics profiling technologies have enabled interrogation of the intertumor/intratumor heterogeneity in the cancer cells and the tumor immune microenvironment. These features may influence the natural history and efficacy of emerging therapies targeting novel molecular and immune pathways, some of which had been deemed undruggable. Thus, comprehensive characterization of the heterogeneities at various levels may facilitate the discovery of biomarkers that enable personalized and rational treatment decisions, and optimize treatment efficacy while minimizing the risk of adverse effects. Such companion biomarkers will also refine HCC treatment algorithms across disease stages for cost-effective patient management by optimizing the allocation of limited medical resources. Despite this promise, the complexity of the intertumor/intratumor heterogeneity and ever-expanding inventory of therapeutic agents and regimens have made clinical evaluation and translation of biomarkers increasingly challenging. To address this issue, novel clinical trial designs have been proposed and incorporated into recent studies. In this review, we discuss the latest findings in the molecular and immune landscape of HCC for their potential and utility as biomarkers, the framework of evaluation and clinical application of predictive/prognostic biomarkers, and ongoing biomarker-guided therapeutic clinical trials. These new developments may revolutionize patient care and substantially impact the still dismal HCC mortality.

Prostate Cancer: De-regulated Circular RNAs With Efficacy in Preclinical In Vivo Models

Therapy resistance, including castration-resistance and metastasis, remains a major hurdle in the treatment of prostate cancer. In order to identify novel therapeutic targets and treatment modalities for prostate cancer, we conducted a comprehensive literature search on PubMed to identify de-regulated circular RNAs that influence treatment efficacy in preclinical prostate cancer-related in vivo models. Our analysis identified 49 circular RNAs associated with various processes, including treatment resistance, transmembrane and secreted proteins, transcription factors, signaling cascades, human antigen R, nuclear receptor binding, ubiquitination, metabolism, epigenetics and other target categories. The identified targets and circular RNAs can be further scrutinized through target validation approaches. Down-regulated circular RNAs are candidates for reconstitution therapy, while up-regulated RNAs can be inhibited using small interfering RNA (siRNA), antisense oligonucleotides (ASO) or clustered regularly interspaced short palindromic repeats/CRISPR associated (CRISPR-CAS)-related approaches.

Untangling the Role of MYC in Sarcomas and Its Potential as a Promising Therapeutic Target

MYC plays a pivotal role in the biology of various sarcoma subtypes, acting as a key regulator of tumor growth, proliferation, and metabolic reprogramming. This oncogene is frequently dysregulated across different sarcomas, where its expression is closely intertwined with the molecular features unique to each subtype. MYC interacts with critical pathways such as cell cycle regulation, apoptosis, and angiogenesis, amplifying tumor aggressiveness and resistance to standard therapies. Furthermore, MYC influences the tumor microenvironment by modulating cell-extracellular matrix interactions and immune evasion mechanisms, further complicating therapeutic management. Despite its well-established centrality in sarcoma pathogenesis, targeting MYC directly remains challenging due to its "undruggable" protein structure. However, emerging therapeutic strategies, including indirect MYC inhibition via epigenetic modulators, transcriptional machinery disruptors, and metabolic pathway inhibitors, offer new hope for sarcoma treatment. This review underscores the importance of understanding the intricate roles of MYC across sarcoma subtypes to guide the development of effective targeted therapies. Given MYC's central role in tumorigenesis and progression, innovative approaches aiming at MYC inhibition could transform the therapeutic landscape for sarcoma patients, providing a much-needed avenue to overcome therapeutic resistance and improve clinical outcomes.

Multitarget mechanism of MYC inhibition by the bacterial lon protease in disease

Identifying specific inhibitors of the MYC oncogene has been challenging, due to off target effects associated with MYC inhibition. This study investigated how the recombinant Escherichia coli Lon protease (rLon), which targets MYC in human cells, inhibits MYC over-activation in models of infection and cancer. In silico predictions identified specific peptide domains of bacterial Lon that target MYC and the affinity of these peptides for MYC was investigated by surface plasmon resonance. The N-terminal domain of rLon was shown to interact with the C-terminal, leucine zipper domain of MYC and MAX and to prevent MYC/MAX dimerization. Furthermore, rLon targeted and degraded c-MYC in vitro and in cellular models, through the peptidase domain. In a model of kidney infection, rLon treatment prevented, c-MYC, N-MYC and L-MYC over-expression, MYC-dependent gene expression, specifically renal toxicity genes and pathology, suggesting that rLon recognizes and corrects MYC dysregulation in this disease. The findings describe a multitarget mechanism of MYC inhibition by rLon, and the combined effects achieved by the Lon domains, targeting different MYC epitopes and MYC-dependent functions, with no evidence of toxicity or detrimental effects on homeostatic MYC expression.

MYC in cancer: from undruggable target to clinical trials

MYC is among the most infamous oncogenes in cancer. A notable feature that distinguishes it from other common oncogenes is that its deregulation is not usually due to direct mutation, but instead to its relentless activation by other oncogenic lesions. These signalling pathways funnel through MYC to execute the transcriptional programmes that eventually lead to the uncontrolled proliferation of cancer cells. Indeed, deregulated MYC activity may be linked to most - if not all - human cancers. Despite this unquestionable role of MYC in tumour development and maintenance, no MYC inhibitor has yet been approved for clinical use. The main reason is that MYC has long fallen into the category of 'undruggable' or 'difficult-to-drug' targets, mainly because of its intrinsically disordered structure, which is not amenable to traditional drug development strategies. However, in recent years, attempts to develop MYC inhibitors have multiplied, and the first clinical trials have been testing their efficacy in patients. We are finally reaching the point at which its inhibition seems clinically viable. This Review provides an overview of the various strategies to inhibit MYC, focusing on the most recently described inhibitors and those that have reached clinical trials.

Immunomodulatory role of exosome-derived content in pediatric medulloblastoma: a molecular subgroup perspective

Medulloblastoma (MB) is the most common malignant brain tumor in children, comprising four distinct subgroups: wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4. MYC amplification and metastatic dissemination are challenges in clinical management, and tumor-associated macrophages (TAMs) play an essential role in these intricate molecular processes. However, the influence of immune cells in MB metastasis and MYC-amp is unclear. Secretion of extracellular vesicles (EVs) has emerged as a pivotal mediator facilitating communication within the tumor microenvironment, orchestrating coordinated responses among immune cells during tumor initiation, progression, and tumor dissemination. Here, we sought to elucidate the role of exosome-derived MBs in promoting specific patterns of TAM polarization across different molecular subgroups of MB cell lines. CIBERSORTx analysis using a single-cell RNA dataset revealed an increase in M0 macrophages and a decreased proportion of M2 macrophages in MB patients with tumor dissemination in the central nervous system (CNS). Cell-derived exosomes were found to secrete high levels of IL-4, IL-10, and TGF-β, indicative of a protumor M2-profile pattern. Moreover, EVs from SHH TP53-mutated, Group 3/4, and MYC-amplified MBs induced dissimilar patterns of TNF-α and/or IL-1β overexpression. This study demonstrates that exosomes from pediatric MBs promote a predominant M2-macrophage phenotype and Group 3, Group 4, SHH TP53-mutated, and MYC-amplified MBs induced a mixed M1/M2 response pattern. These findings shed light on the pivotal role of exosomes in modulating the immune response, potentially contributing to immune escape in this malignant neoplasm.

Comprehensive dissection of cis-regulatory elements in a 2.8 Mb topologically associated domain in six human cancers

Cis-regulatory elements (CREs), such as enhancers and promoters, are fundamental regulators of gene expression and, across different cell types, the MYC locus utilizes a diverse regulatory architecture driven by multiple CREs. To better understand differences in CRE function, we perform pooled CRISPR inhibition (CRISPRi) screens to comprehensively probe the 2.8 Mb topologically-associated domain containing MYC in 6 human cancer cell lines with nucleotide resolution. We map 32 CREs where inhibition leads to changes in cell growth, including 8 that overlap previously identified enhancers. Targeting specific CREs decreases MYC expression by as much as 60%, and cell growth by as much as 50%. Using 3-D enhancer contact mapping, we find that these CREs almost always contact MYC but less than 10% of total MYC contacts impact growth when silenced, highlighting the utility of our approach to identify phenotypically-relevant CREs. We also detect an enrichment of lineage-specific transcription factors (TFs) at MYC CREs and, for some of these TFs, find a strong, tumor-specific correlation between TF and MYC expression not found in normal tissue. Taken together, these CREs represent systematically identified, functional regulatory regions and demonstrate how the same region of the human genome can give rise to complex, tissue-specific gene regulation.

NOX4 modulates breast cancer progression through cancer cell metabolic reprogramming and CD8+ T cell antitumor activity

Introduction

Breast cancer is the most frequently diagnosed malignancy and a leading cause of cancer-related mortality among women worldwide. Although NADPH oxidase 4 (NOX4) has been implicated in various oncogenic processes, its exact function in breast cancer progression, metabolic reprogramming, and immune modulation remains unclear.

Methods

We used murine 4T1 and EO771 breast cancer models to generate NOX4 knockout (KO) cell lines via CRISPR/Cas9. In vitro assays (cell proliferation, colony formation, wound healing, and Seahorse metabolic analyses) and in vivo orthotopic tumor studies assessed the impact of NOX4 loss. Transcriptomic changes were identified through RNA sequencing and gene set enrichment analysis. We performed MYC knockdown in NOX4 KO cells to investigate its mechanistic role. Flow cytometry characterized tumor-infiltrating immune cells. Finally, NOX4-overexpressing cells were tested for survival benefit and response to dual-checkpoint immunotherapy (anti-PD-1/anti-CTLA-4).

Results

NOX4 deletion accelerated tumor growth in vivo and enhanced proliferation, colony formation, and migratory capacity in vitro. Metabolic profiling showed that NOX4 KO cells had elevated glycolysis and fatty acid oxidation, along with increased mitochondrial mass. Transcriptomic and enrichment analyses revealed MYC pathway activation in NOX4 KO cells; suppressing MYC reversed these hyperproliferative and metabolic changes. Immunologically, NOX4 KO reduced CD8+ T cell infiltration and function, partially due to lowered CCL11/CCL5 levels, while PD-L1 expression was upregulated. In contrast, NOX4 overexpression improved survival in mice and synergized with checkpoint blockade, demonstrating a positive effect on anti-tumor immunity.

Discussion

These findings show that NOX4 constrains breast cancer aggressiveness by limiting MYC-driven metabolic adaptations and supporting CD8+ T cell-mediated immunity. Loss of NOX4 promotes a more malignant phenotype and dampens T cell responses, whereas its overexpression prolongs survival and enhances checkpoint inhibitor efficacy. Therapeutically targeting the NOX4-MYC axis and leveraging NOX4's immunomodulatory capacity could offer promising strategies for breast cancer management.

EZH2 inhibition sensitizes MYC-high medulloblastoma cancers to PARP inhibition by regulating NUPR1-mediated DNA repair

MYC-driven medulloblastomas (MB) are highly aggressive pediatric brain tumors with poor outcomes, and effective therapies remain limited despite intensive multimodal treatments. Targeting MYC directly is challenging, but exploiting MYC-mediated synthetic lethality holds promise. In this study, we investigated the combined effects of EZH2 and PARP inhibitors in MYC-high medulloblastoma and demonstrated that EZH2 inhibition significantly increased the sensitivity of MYC-high MB tumor cells to PARP inhibitors. This effect occurs through the upregulation of NUPR1, which promotes error-prone non-homologous end-joining (NHEJ) DNA repair by facilitating the recruitment of the XRCC4-LIG4 complex to DNA damage sites. This amplification of error-prone NHEJ DNA repair leads to genetic instability and eventual cell death in cells treated with the PARP inhibitor. The synergistic effect of EZH2 and PARP inhibitors was further validated in both in vitro and in vivo MB models without observed toxicity. These findings reveal a novel therapeutic strategy for MYC-high MB by co-targeting EZH2 and PARP, suggesting that this combination could potentially overcome the clinical challenges associated with this aggressive tumor subtype and warrants further investigation in clinical trials.

PRMT6 promotes colorectal cancer progress via activating MYC signaling

Colorectal cancer (CRC) remains a major global health challenge, with high rates of incidence and mortality. This study investigates the role of protein arginine methyltransferase 6 (PRMT6) as an oncogene in CRC and its mechanistic involvement in tumor progression. We found that PRMT6 is significantly overexpressed in CRC tissues compared to adjacent normal tissues and is associated with poorer patient survival. Functional assays demonstrated that PRMT6 promotes CRC cell proliferation, migration, and invasion. Mechanistically, PRMT6 enhances MYC signaling by stabilizing c-MYC through mono-methylation at arginine 371, which inhibits c-MYC poly-ubiquitination and subsequent degradation. This post-translational modification is crucial for PRMT6-induced cancer cell proliferation. Xenograft models further validated that PRMT6 knockdown results in reduced tumor growth and decreased c-MYC levels. Our findings highlight PRMT6 as a key regulator of c-MYC stability and CRC progression, suggesting that targeting PRMT6 or its effects on c-MYC could offer a promising strategy for CRC treatment.

Dynamic Multilevel Regulation of EGFR, KRAS, and MYC Oncogenes: Driving Cancer Cell Proliferation Through (Epi)Genetic and Post-Transcriptional/Translational Pathways

The epidermal growth factor receptor (EGFR) regulates gene expression through two primary mechanisms: as a growth factor in the nucleus, where it translocates upon binding its ligand, or via its intrinsic tyrosine kinase activity in the cytosol, where it modulates key signaling pathways such as RAS/MYC, PI3K, PLCγ, and STAT3. During tumorigenesis, these pathways become deregulated, leading to uncontrolled proliferation, enhanced migratory and metastatic capabilities, evasion of programmed cell death, and resistance to chemotherapy or radiotherapy. The RAS and MYC oncogenes are pivotal in tumorigenesis, driving processes such as resistance to apoptosis, replicative immortality, cellular invasion and metastasis, and metabolic reprogramming. These oncogenes are subject to regulation by a range of epigenetic and post-transcriptional modifications. This review focuses on the deregulation of EGFR, RAS, and MYC expression caused by (epi)genetic alterations and post-translational modifications. It also explores the therapeutic potential of targeting these regulatory proteins, emphasizing the importance of phenotyping neoplastic tissues to inform the treatment of cancer.

Targeting protein synthesis pathways in MYC-amplified medulloblastoma

MYC is one of the most deregulated oncogenic transcription factors in human cancers. MYC amplification/or overexpression is most common in Group 3 medulloblastoma and is positively associated with poor prognosis. MYC is known to regulate the transcription of major components of protein synthesis (translation) machinery, leading to promoted rates of protein synthesis and tumorigenesis. MTOR signaling-driven deregulated protein synthesis is widespread in various cancers, including medulloblastoma, which can promote the stabilization of MYC. Indeed, our previous studies demonstrate that the key components of protein synthesis machinery, including mTOR signaling and MYC targets, are overexpressed and activated in MYC-amplified medulloblastoma, confirming MYC-dependent addiction of enhanced protein synthesis in medulloblastoma. Further, targeting this enhanced protein synthesis pathway with combined inhibition of MYC transcription and mTOR translation by small-molecule inhibitors, demonstrates preclinical synergistic anti-tumor potential against MYC-driven medulloblastoma in vitro and in vivo. Thus, inhibiting enhanced protein synthesis by targeting the MYC indirectly and mTOR pathways together may present a highly appropriate strategy for treating MYC-driven medulloblastoma and other MYC-addicted cancers. Evidence strongly proposes that MYC/mTOR-driven tumorigenic signaling can predominantly control the translational machinery to elicit cooperative effects on increased cell proliferation, cell cycle progression, and genome dysregulation as a mechanism of cancer initiation. Several small molecule inhibitors of targeting MYC indirectly and mTOR signaling have been developed and used clinically with immunosuppressants and chemotherapy in multiple cancers. Only a few of them have been investigated as treatments for medulloblastoma and other pediatric tumors. This review explores concurrent targeting of MYC and mTOR signaling against MYC-driven medulloblastoma. Based on existing evidence, targeting of MYC and mTOR pathways together produces functional synergy that could be the basis for effective therapies against medulloblastoma.

Endothelial-secreted Endocan activates PDGFRA and regulates vascularity and spatial phenotype in glioblastoma

Extensive neovascularization is a hallmark of glioblastoma (GBM). In addition to supplying oxygen and nutrients, vascular endothelial cells provide trophic support to GBM cells via paracrine signaling. Here we report that Endocan (ESM1), an endothelial-secreted proteoglycan, confers enhanced proliferative, migratory, and angiogenic properties to GBM cells and regulates their spatial identity. Mechanistically, Endocan exerts at least part of its functions via direct binding and activation of the PDGFRA receptor. Subsequent downstream signaling enhances chromatin accessibility of the Myc promoter and upregulates Myc expression inducing stable phenotypic changes in GBM cells. Furthermore, Endocan confers radioprotection on GBM cells in vitro and in vivo. Inhibition of Endocan-PDGFRA signaling with ponatinib increases survival in the Esm1 wild-type but not in the Esm1 knock-out mouse GBM model. Our findings identify Endocan and its downstream signaling axis as a potential target to subdue GBM recurrence and highlight the importance of vascular-tumor interactions for GBM development.