Liping Shu

Homeostasis is essential for hematopoiesis, and its dysregulation can lead to severe pathological conditions. Retinoic acid (RA) is a key regulator that exerts concentration-dependent effects on both embryonic and adult hematopoiesis. However, the mechanisms that modulate RA signaling in hematopoietic processes remain poorly understood. Using zebrafish as a model, we identified angiopoietin-like protein 5 (Angptl5) as a critical regulator of hematopoietic homeostasis. Loss of Angptl5 function resulted in myeloid hyperplasia in the anterior lateral plate mesoderm (ALPM) and anterior expansion of erythroid progenitors in the posterior lateral plate mesoderm (PLPM)—phenotypes consistent with attenuated RA signaling. Molecular analyses confirmed impaired RA signaling in angptl5 ^Δ10/Δ10 mutants, and exogenous RA supplementation fully rescued the hematopoietic defects. Mechanistically, we found that Angptl5 transcriptionally activates retinol dehydrogenase dhrs9 through its interaction with Integrin α6lβ5. Our findings establish Angptl5 as a novel and essential regulator of embryonic hematopoiesis and reveal a previously unrecognized mechanism controlling hematopoietic homeostasis. These insights position Angptl5 as a potential therapeutic target for hematological disorders.

Table S1. NRAS mutations in leukemia

Table S2. KRAS mutations in leukemia

Table S3. HRAS mutations in leukemia

Introduction: CDK2 (Cyclin-dependent kinase 2) is an oncogenic cyclin-dependent kinase with potent mitogenic and immunosuppressive functions. Despite extensive research on CDK2 inhibitors, the lack of selectivity has made it unclear whether CDK2 inhibition specifically facilitate immunogenic cell death.Methods: We used CRISPR-Cas9 system to generate Cdk2^-/- MCA205 cells. Tumor cells were inoculated subcutaneously into mice while administering MTX (mitoxantrone) or anti-PD-1 antibodies treatment to observe tumor growth curves. Next, immune cell infiltration in tumor microenvironment was detected by immunofluorescence. Furthermore, apoptosis pathway was evaluated by flow cytometry and western blot. The hallmarks of immunogenic cell death were detected by flow cytometry, ELISA or qRT-PCR.Results: We found that mice bearing Cdk2^-/- cancer cells exhibit slower tumor growth than WT cells after anthracycline analogue MTX treatment, and this phenomenon is dependent on the immune system. Furthermore, our data exhibits that Cdk2^-/- cancer cells treated with MTX trigger a more robust immunostimulatory responses than WT cells, including apoptosis stress response, surface calreticulin expression, endoplasmic reticulum stress response, HMGB1 (High Mobility Group Box 1) release, and type-1 interferon response. Discussion: This study not only suggests that CDK2 inhibition improves the outcome of chemotherapy by enhancing the type-1 interferon response but also investigates the synergistic effects of CDK2 inhibition with MTX or anti-PD-1 antibodies in immunocompetent mice.

Table S2. KRAS mutations in leukemia

Table S1. NRAS mutations in leukemia

RAS mutations are prevalent in leukemia, including mutations at G12, G13, T58, Q61, K117, and A146. These mutations are often crucial for tumor initiation, maintenance, and recurrence. Although much is known about RAS function in the last 40 years, a substantial knowledge gap remains in understanding the mutation-specific biological activities of RAS in cancer and the approaches needed to target specific RAS mutants effectively. The recent approval of KRASG12C inhibitors, adagrasib and sotorasib, has validated KRAS as a direct therapeutic target and demonstrated the feasibility of selectively targeting specific RAS mutants. Nevertheless, KRASG12C remains the only RAS mutant successfully targeted with FDA-approved inhibitors for cancer treatment in patients, limiting its applicability for other oncogenic RAS mutants, such as G12D, in leukemia. Despite these challenges, new approaches have generated optimism about targeting specific RAS mutations in an allele-dependent manner for cancer therapy, supported by compelling biochemical and structural evidence, which inspires further exploration of RAS allele-specific vulnerabilities. This review will discuss the recent advances and challenges in the development of therapies targeting RAS signaling, highlight emerging therapeutic strategies, and emphasize the importance of allele-specific approaches for leukemia treatment.

Table S3. HRAS mutations in leukemia