Horn of plenty: Value of the international registry for pediatric chronic myeloid leukemia

Chronic myeloid leukemia (CML) in minors is a rare disease which can be effectively treated by tyrosine kinase inhibitors (TKIs) since the year 2000. A majority of pediatricians will encounter one or two CML patients in the course of their careers and will typically have to rely on written information along with their own intuition to provide care. Knowledge of response to TKIs and of age-specific side effects has an impact on the design of pediatric CML trials in many ways aiming to contribute toward greater predictability of clinical improvements. Information from a registry on a rare disease like CML offers the enormous benefit of enabling treating physicians to interact and share their collective experience. The International Registry on Pediatric CML (IR-PCML) was founded at Poitiers/France almost 10 years ago. Since then, the number of collaboration centers and in parallel of registered patients continuously increased (> 550 patients as of December 2019). Ideally, from a given treatment center in a country data are transferred to a national coordinator who interacts with the IR-PCML. In the sense of quality assurance, the registry can offer dissemination of knowledge on state-of-the-art diagnostics (including reference appraisal), optimal treatment approaches, and follow-up procedures within a network that is exerting its strength via participation. With continuous growth during the recent years, very rare subgroups of patients could be identified (e.g., CML diagnosed at age < 3 years, children presenting with specific problems at diagnosis or during course of treatment) which had not been described before. Publications coming from the IR-PCML disseminated this useful information derived from patients who robustly participate and share information about their disease, among themselves and with their caregivers and clinicians. Patient input driving the collection of data on this rare leukemia is the basis for the considerable success of bringing new therapeutics into clinical use.

Targeting autophagy potentiates the anti-tumor effect of PARP inhibitor in pediatric chronic myeloid leukemia

Due to its potent cytotoxicity in BRCA-mutated tumors, synthetic lethality elicited by poly (ADP-ribose) polymerase (PARP) inhibitor gives renewed enthusiasm to researching and developing anti-cancer therapies. Chronic myeloid leukemia (CML) is a type of cancers that starts in certain blood-forming cells of the bone marrow. Here, we showed that poly (ADP-ribose) polymerase (PARP) inhibitor talazoparib could induce a concentration-dependent cytotoxicity in CML cells derived from pediatric patients. During talazoparib treatment, autophagy was markedly activated, which was confirmed by the accumulation of autophagosomes, decrease of SQSTM1 and up-regulation of LC3-II. Inhibition of autophagy by pharmaceutical inhibitor chloroquine or small-interfering RNA siATG5 significantly increased the cytotoxicity of talazoparib in pediatric CML cells and elicited synergistic anti-tumor effect in patient-derived xenograft model. Our data demonstrated that autophagy played a cyto-protective role in talazoparib-treated pediatric CML and co-treatment with talazoparib and autophagy inhibitor could induce synergetic anti-tumor effect, providing novel insights for pediatric CML treatment.