RESUMEN
The combined influence of oncogenic drivers, genomic instability, and/or DNA damage repair deficiencies increases replication stress in cancer. Cells with high replication stress rely on the upregulation of checkpoints like those governed by CHK1 for survival. Previous studies of the CHK1 inhibitor prexasertib demonstrated activity across multiple cancer types. Therefore, we sought to (1) identify markers of prexasertib sensitivity and (2) define the molecular mechanism(s) of intrinsic and acquired resistance using preclinical models representing multiple tumor types. Our findings indicate that while cyclin E dysregulation is a driving mechanism of prexasertib response, biomarkers associated with this aberration lack sufficient predictive power to render them clinically actionable for patient selection. Transcriptome analysis of a pan-cancer cell line panel and in vivo models revealed an association between expression of E2F target genes and prexasertib sensitivity and identified innate immunity genes associated with prexasertib resistance. Functional RNAi studies supported a causal role of replication fork components as modulators of prexasertib response. Mechanisms that protect cells from oncogene-induced replication stress may safeguard tumors from such stress induced by a CHK1 inhibitor, resulting in acquired drug resistance. Furthermore, resistance to prexasertib may be shaped by innate immunity.
RESUMEN
<p><b>OBJECTIVE</b>To observe the clinical effect of Huikangling Tablet (HT, extracted from Scabrous Patrinia root) on peripheral blood micrometastasis of differentiated thyroid carcinoma (DTC) patients.</p><p><b>METHODS</b>Totally 87 DTC patients with positive micrometastasis were randomly assigned to the treatment group (45 cases) and the control group (42 cases). DTC endocrine inhibition treatment standards were executed in all patients. They all took levothyroxine sodium (50 microg/tablet, from low dose, 25 microg each time, once per day, 0.5 h before breakfast), and its dosage was gradually added one week later. The dosage was adjusted according to tested results of TSH combined recurrence risk stratification and endocrine suppression induced adverse reactions risk stratification. Patients in the treatment group took HT (0.4 g per tablet, 3 tablets each time, three times per day for a total of 12 weeks) combined TSH suppression therapy, while those in the control group only received TSH suppression therapy. Peripheral micrometastatic cytokeratin 19 (CK19) and polymorphic epithelial mucin1 (MUC1) were detected by FCM at week 4 and 12. Meanwhile, distant metastasis and adverse reactions were observed.</p><p><b>RESULTS</b>After 4-week treatment positive micrometastasis was shown in 18 cases (40%) of the treatment group and 29 cases (69%) in the control group with statistical difference (chi2 = 5.68, P < 0.05). After 12-week treatment positive micrometastasis was shown in 7 cases (15.6%) of the treatment group and 17 cases (44.7%) in the control group with statistical difference (chi2 = 8.49, P < 0.01). Pulmonary metastasis occurred in 2 cases and bone metastasis in 1 case of the control group at follow-ups. Cervical lymph node metastasis without accompanied recurrence of thyroid cancer occurred in one case of the treatment group. No obvious liver or renal abnormalities occurred.</p><p><b>CONCLUSION</b>HT inhibited peripheral blood micrometastasis of DTC patients and its mechanism needed to be further studied.</p>