A functional genomics screen identifying blood cell development genes in Drosophila by undergraduates participating in a course-based research experience

Undergraduate students participating in the UCLA Undergraduate Research Consortium for Functional Genomics (URCFG) have conducted a two-phased screen using RNA interference (RNAi) in combination with fluorescent reporter proteins to identify genes important for hematopoiesis in Drosophila. This screen disrupted the function of approximately 3500 genes and identified 137 candidate genes for which loss of function leads to observable changes in the hematopoietic development. Targeting RNAi to maturing, progenitor, and regulatory cell types identified key subsets that either limit or promote blood cell maturation. Bioinformatic analysis reveals gene enrichment in several previously uncharacterized areas, including RNA processing and export and vesicular trafficking. Lastly, the participation of students in this course-based undergraduate research experience (CURE) correlated with increased learning gains across several areas, as well as increased STEM retention, indicating that authentic, student-driven research in the form of a CURE represents an impactful and enriching pedagogical approach.

Maternal and neonatal outcomes in 80 patients diagnosed with non-Hodgkin lymphoma during pregnancy: results from the International Network of Cancer, Infertility and Pregnancy

This cohort study of the International Network on Cancer, Infertility and Pregnancy (INCIP) reports the maternal and neonatal outcomes of 80 pregnant patients diagnosed with non-Hodgkin lymphoma (NHL) between 1986 and 2019, focussing on 57 (71%) patients with diffuse large B-cell lymphoma (DLBCL). Of all 80 patients, 54 (68%) pregnant patients received chemotherapy; mostly (89%) CHOP-like (cyclophosphamide, doxorubicin, vincristine, and prednisone) regimens. Four early pregnancies were terminated. Among 76 ongoing pregnancies, there was one stillbirth (1·3%). Overall, there was a high incidence of small for gestational age neonates (39%), preterm delivery (52%), obstetric (41%) and neonatal complications (12·5%), and this could not exclusively be explained by the receipt of antenatal chemotherapy. Half of preterm deliveries (46%) were planned in order to tailor oncological treatment. The 3-year progression-free and overall survival for patients with DLBCL treated with rituximab-CHOP was 83·4% and 95·7% for limited stage (n = 29) and 60·6% and 73·3% for advanced stage (n = 15). Of 36 pregnant patients who received rituximab, five (13%) cases with neonatal complications and three (8%) with maternal infections were reported. In conclusion, standard treatment for DLBCL can be offered to pregnant patients in obstetric centres that cater for high-risk patients.

RUNX1 prevents oestrogen-mediated AXIN1 suppression and β-catenin activation in ER-positive breast cancer

Recent high-throughput studies revealed recurrent RUNX1 mutations in breast cancer, specifically in oestrogen receptor-positive (ER⁺) tumours. However, mechanisms underlying the implied RUNX1-mediated tumour suppression remain elusive. Here, by depleting mammary epithelial cells of RUNX1 in vivo and in vitro, we demonstrate combinatorial regulation of AXIN1 by RUNX1 and oestrogen. RUNX1 and ER occupy adjacent elements in AXIN1's second intron, and RUNX1 antagonizes oestrogen-mediated AXIN1 suppression. Accordingly, RNA-seq and immunohistochemical analyses demonstrate an ER-dependent correlation between RUNX1 and AXIN1 in tumour biopsies. RUNX1 loss in ER⁺ mammary epithelial cells increases β-catenin, deregulates mitosis and stimulates cell proliferation and expression of stem cell markers. However, it does not stimulate LEF/TCF, c-Myc or CCND1, and it does not accelerate G1/S cell cycle phase transition. Finally, RUNX1 loss-mediated deregulation of β-catenin and mitosis is ameliorated by AXIN1 stabilization in vitro, highlighting AXIN1 as a potential target for the management of ER⁺ breast cancer.

The tumour suppressor RUNX1 is often lost or mutated in oestrogen receptor-positive breast cancers. In this study, the authors demonstrate that the loss of RUNX1 unleashes oestrogen-mediated inhibition of AXIN1, a negative regulator of β-catenin, resulting in β-catenin signalling-mediated cancer cell proliferation and mitosis deregulation.