NU-DHL-1

High Expression Level of Bcl-2 Predicts Sensitivity to BM-1197

DLBCL and other types of malignant lymphomas frequently become resistant to traditional treatments resulting in negative patient prognoses. Overexpression of Bcl-2 protein contributes to this resistance. Sun's team evaluated BM-1197 as a BH3 domain mimic that targets Bcl-2 to test its effectiveness against DLBCL and Burkitt lymphoma.

Researchers measured Bcl-2 family protein levels across eight B cell-derived lymphoma cell lines including OCI-ly1, OCI-ly8, OCI-ly19, Su-DHL-4, Nu-DHL-1, Raji, Ramos, and Namalwa as well as the T-cell-derived acute T-cell leukemia cell line Jurkat. As illustrated in Fig. 1a Bcl-2 expression levels were high in diffuse large B-cell lymphoma cell lines but remained low in Burkitt and Jurkat cells as shown in Fig. 1a. The impact of BM-1197 on lymphoma cell growth was measured using a CCK-8 assay following treatment. Figure 2 displays the IC₅₀ values of BM-1197 for each cell line which demonstrates sensitivity in OCI-ly1, OCI-ly8, and OCI-ly19 cells with IC₅₀ values ranging between 0.2 and 0.5 μM (Fig. 1b). A time-dependent reduction in OCI-ly8 cell viability was observed when treated with BM-1197 across 24, 48, and 72-hour intervals (Fig. 1c). To explore potential synergistic effects with chemotherapy, BM-1197 was tested with doxorubicin, vincristine, and gemcitabine in OCI-ly8 cells. The cell growth inhibition observed from the drug combination reached a synergistic effect as demonstrated in the figures. 1d, e, f.

Fig. 1. High expression level of BCL-2 predicts sensitivity to BM1197 (Sun Y, Jiang W, et al., 2020).

Fig. 2. The IC₅₀ values (μM) of BM-1197 in NHL cell lines (Sun Y, Jiang W, et al., 2020).

Downregulation of miR-155 Promotes Vincristine Resistance

DLBCL stands as the most common non-Hodgkin's lymphoma subtype while approximately 40% of patients treated experience disease relapse or develop treatment resistance due to molecular resistance mechanisms including miRNA expression changes. Due et al. Due et al. examined miR-155's function in vincristine resistance within R-CHOP treatment for DLBCL while assessing its predictive biomarker and therapeutic target potential.

Research using lentiviral vectors to modify miR-155 levels demonstrated that elevated miR-155 expression improved vincristine sensitivity in both drug-sensitive and drug-resistant GCB-DLBCL cell lines including SU-DHL-5 and OCI-Ly7. SU-DHL-5 cells showed increased vincristine resistance when miR-155 levels were reduced while OCI-Ly7 cells did not demonstrate this effect. The miR-155 knockout demonstrated its regulatory role through enhanced vincristine resistance. Research shows that miR-155 affects important cellular processes like G2/M checkpoints and spindle assembly which vincristine targets to determine treatment effectiveness. In addition, ABC cell lines RIVA and NU-DHL-1, characterized by intrinsically intermediate response to vincristine and comparably high endogenous expression of miR-155, were similarly analyzed. Applying the TuD model system decreased miR-155 expression in RIVA cells; however, it did not cause unambiguous effect on vincristine sensitivity (Fig. 3BI-BII). Although functionality of the model systems was confirmed (Fig. 4), transduction with LV/miR-155 in RIVA and LV/TuD-155 in NU-DHL-1 did not generate significant changes in intracellular levels of miR-155, and consequently, vincristine dose-response analysis was not performed (Fig. 3AI and DI). Overexpression of miR-155 in NU-DHL-1 cells did not affect vincristine response either (Fig. 3CI-CII), indicating that miR-155 does not play a pivotal role in vincristine response in ABC cells as opposed to GCB cells.

Fig. 3. Manipulation of miR-155 expression in ABC-DLBCL cell lines do not affect
vincristine response (Sun Y, Jiang W, et al., 2020).

Fig. 4. Suppression of miR-155 by TuD-155 (Sun Y, Jiang W, et al., 2020).