Screening of Phenanthroquinolizidine Alkaloid Derivatives for Inducing Cell Death of L1210 Leukemia Cells with Negative and Positive P-glycoprotein Expression

Abstract

We describe the screening of a set of cryptopleurine derivatives, namely thienoquinolizidine derivatives and (epi-)benzo analogs with bioactive phenanthroquinolizidine alkaloids that induce cytotoxic effects in the mouse lymphocytic leukemia cell line L1210. We used three variants of L1210 cells: i) parental cells (S) negative for P-glycoprotein (P-gp) expression; ii) P-glycoprotein positive cells (R), obtained by selection with vincristine; iii) P-glycoprotein positive cells (T), obtained by stable transfection with a human gene encoding P-glycoprotein. We identified the most effective derivative 11 with a median lethal concentration of ≈13 μM in all three L1210 cell variants. The analysis of the apoptosis/necrosis induced by derivative 11 revealed that cell death was the result of apoptosis with late apoptosis characteristics. Derivative 11 did not induce a strong alteration in the proportion of cells in the G1, S or G2/M phase of the cell cycle, but a strong increase in the number of S, R and T cells in the subG1 phase was detected. These findings indicated that we identified the most effective inducer of cell death, derivative 11, and this derivative effectively induced cell death in S, R and T cells at similar inhibitory concentrations independent of P-gp expression.

Development of Resistance to Endoplasmic Reticulum Stress-Inducing Agents in Mouse Leukemic L1210 Cells

“…Each of the variants obtained was able to proliferate at concentrations of the respective stressor to which it was accustomed of at least 10-fold higher than the concentration used with the original S line, and the process was completed over repeated passages. The properties of the novel cell variants were compared to those in parental cells, consisting of three variants of L1210 cells (S, R and T) suitable for studying the cytotoxic effects of substances in relation to P-gp expression [28]. In addition to significant resistance to VCR, which is a prototypical P-gp substrate, both P-gp-positive lines also showed moderate cross-resistance to Tun and Thap and, in contrast, hypersensitivity to MG-132 (Figure 1).…”

“…Statistical significance was analyzed using an unpaired Student's t-test. Validation of Equation (1) was previously described [28]:…”

Heterocycles in Medicinal Chemistry

“…A publication on pharmacological topics presents both the search for mechanisms of actions of naphthoquinone-based chemotherapeutics active against acute myeloid leukemia [10] and studies evaluating cryptopleurine (thienoquinolizidine derivatives and (epi-)benzo analogues) phenanthroquinolizidine alkaloids inducing cell death of leukemia cells [11].…”

Synthesis of Pyrazoloazepines from 5‐Aminopyrazoles and Study of Their Cytotoxicity in Cancer Treatment

“…where N is the percentage (from a control in the absence of a drug) of cell viability after cultivation in the presence of the derivatives tested at concentration c; IC 50 is the concentration of a substance at which N=50 %; IC 50 values were calculated from three independent measurements. The significance of differences was analyzed with an unpaired Student's t‐test [22] …”

“…The significance of differences was analyzed with an unpaired Student's t-test. [22] Antibacterial activity of newly synthesized compounds assayed in vitro: The antibacterial activity of newly synthesized compounds was evaluated by macrodilution method using G + bacteria (Firmicutes)…”