Induction of Paraptotic Cell Death in Breast Cancer Cells by a Novel Pyrazolo[3,4-h]quinoline Derivative through ROS Production and Endoplasmic Reticulum Stress

Abstract

Chemotherapy has been a standard intervention for a variety of cancers to impede tumor growth, mainly by inducing apoptosis. However, development of resistance to this regimen has led to a growing interest and demand for drugs targeting alternative cell death modes, such as paraptosis. Here, we designed and synthesized a novel derivative of a pyrazolo[3,4-h]quinoline scaffold (YRL1091), evaluated its cytotoxic effect, and elucidated the underlying molecular mechanisms of cell death in MDA-MB-231 and MCF-7 breast cancer (BC) cells. We found that YRL1091 induced cytotoxicity in these cells with numerous cytoplasmic vacuoles, one of the distinct characteristics of paraptosis. YRL1091-treated BC cells displayed several other distinguishing features of paraptosis, excluding autophagy or apoptosis. Briefly, YRL1091-induced cell death was associated with upregulation of microtubule-associated protein 1 light chain 3B, downregulation of multifunctional adapter protein Alix, and activation of extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase. Furthermore, the production of reactive oxygen species (ROS) and newly synthesized proteins were also observed, subsequently causing ubiquitinated protein accumulation and endoplasmic reticulum (ER) stress. Collectively, these results indicate that YRL1091 induces paraptosis in BC cells through ROS generation and ER stress. Therefore, YRL1091 can serve as a potential candidate for the development of a novel anticancer drug triggering paraptosis, which may provide benefit for the treatment of cancers resistant to conventional chemotherapy.

Bisphosphonates Fight Against Cancer Roots: Zoledronic Acid Targets Chemo-Resistant Polyploid Giant Cancer Cells

“…We have here shown that ZA, a bisphosphonate safely used for osteoporosis, has a signi cant effect on the removal of PGCCs. It has recently been observed that concomitant use of this drug with cisplatin in breast, bladder, kidney, and lung cancer has increased the e cacy of treatment (34)(35)(36)(37). However, to date, no study has speci cally examined the effect of ZA on PGCCs.…”

“…3). Although formation of vacuoles has previously been reported in response to cancer therapeutics [34] and some investigators have attributed them to therapy resistance [35], the content and function of these structures are yet elusive.…”

Suppression of Tumor Growth and Cell Migration by Indole-Based Benzenesulfonamides and Their Synergistic Effects in Combination with Doxorubicin

“…A549 lung cancer cells were cultured in RPMI containing 10% FBS and 1% antibiotic–antimycotic (composition given above). All cells were cultured and maintained in a humidified incubator at 37 °C with 5% CO 2 until 80–90% confluence and then trypsinized with 0.05%/0.5 mM trypsin−EDTA for experimental assays or a new passage culture, as previously described [ 48 , 49 ].…”

“…The cells were washed and lysed with lysis buffer on ice. Electrophoresis and immunoblotting were performed according to procedures reported previously [ 49 , 50 ]. Briefly, lysates containing equal amounts of proteins were resolved by SDS-PAGE and transferred to nitrocellulose membranes at 100 V for 90 min.…”

“…MCF-7 and SK-BR-3 cells were plated in 60-mm culture dishes at a density of 1 × 10 6 and 1.5 × 10 6 cells/well, respectively, and incubated at 37 °C overnight to 75–80% confluence [ 49 ]. Afterward, control siRNA and siRNA targeting CA II, IX, or XII were transfected using Lipofectamine 3000 transfection reagent (Invitrogen, Rockford, IL, USA), according to the manufacturer’s instructions.…”