DERL-7

NKL Homeobox Gene MSX1 Overexpression in Hepatosplenic T-Cell Lymphoma

The NKL homeobox genes are essential for hematopoiesis and are known to be dysregulated in T-cell leukemia. However, their function in T-cell lymphomas (AITL, ALCL, ATLL, HSTL, NKTL, PTCL) is not well defined. Nagel et al. identified aberrantly expressed NKL homeobox genes in T-cell lymphomas, focusing on MSX1 in HSTL, to uncover their oncogenic mechanisms and potential therapeutic targets.

To identify a T-cell lymphoma model overexpressing MSX1, they analyzed dataset GSE57083 (123 hematopoietic cell lines), revealing HSTL-derived DERL-2. RQ-PCR confirmed DERL-2 to be overexpressing MSX1 as well as sister line DERL-7 to show higher expression levels (Fig. 1A). MSX1 protein was detected by western blot in DERL-2/7, NK-92 and LOUCY (Fig. 1A). The cell lines share the same origin, being derived from blood and bone marrow of one patient, and display a mixed T-cell (TCR+, CD7+) and NK-cell (CD2+, CD56+) phenotype. The cell lines are therefore a prime candidate to study HSTL mechanism. Cluster analysis of NK and T-cells, shows DERL-2/7 to cluster closer to NK-cells (Fig. 1B). This is in line with HSTL's well-documented NK-like phenotype and they hypothesized MSX1 to contribute to this. They confirmed that NK-specific factor AUTS2 has significantly elevated expression in DERL-2/7 (Fig. 1C) and knockdown of AUTS2 leads to reduction of MSX1 levels (Fig. 1D).

Fig. 1. Gene expression analyses (Nagel S, Pommerenke C, et al., 2019).

4c Pyrazolo[3,4-d]pyrimidine Compound Reduced Cell Viability in Hematological Malignancies

In recent years, several molecular targeted agents have been developed to treat a wide variety of malignancies. However, development of drug resistance and low efficacy observed with hematological malignancies (HMs) urgently call for new therapeutics. Src family kinases (SFKs) have been reported to be deeply involved in hematopoiesis and leukemogenesis, and their signaling pathways have emerged as attractive targets in these diseases. Laurenzana et al. evaluated the anti-tumor effects of 4c pyrazolo[3,4-d]pyrimidine, a SFK inhibitor, on lymphoid (Jurkat, SKMM1, Derl-2/7) and myeloid (Jurl-MK1) cell lines, focusing on its ability to reduce viability, induce apoptosis, and inhibit Fyn activity in HMs.

3 HD-PBMCs, 6 lymphoid (Jurkat, SKMM1, Derl-2, Derl-7, BV-173 and NALM-6), and 5 myeloid cell lines (Jurl-MK1, NB-4, HL-60, OCI-AML3 and Kasumi-1) were treated with a 4c pyrazolo[3-4,d]pyrimidine compound or DMSO control at a concentration of 1–15 μM for 24–72 h to evaluate the effect of the compound on cell viability. The compound had a minimal effect on HD-PBMCs at 15 μM and 24–72 h time points (Fig. 2A). In lymphoid malignancies, Jurkat, SKMM1, and Derl-2 cell lines had a significant reduction of cell viability (∼50%) at 5 μM, and 60–70% at 10 μM. This effect was consistent after 24 h. Derl-7 and BV-173 had a dose-dependent reduction of viability with the highest effects (−25% and −60% at 15 μM) at 48 and 72 h. NALM-6 had a 40% reduction of viability at 15 μM at all time points (Fig. 2B). In myeloid malignancies, Jurl-MK1 and NB-4 had a dose-dependent reduction of viability with the strongest effects observed at 48 and 72 h. HL-60 and OCI-AML3 had a 20% and 30% reduction of viability at 15 μM at all time points, and Kasumi-1 had a 50% reduction of viability at 15 μM at 48 and 72 h (Fig. 2C).

Fig. 2. Cell viability assay after 4c compound treatment in hematological malignancies (Laurenzana I, Caivano A, et al., 2016).