WIN55,212-2 induces cytoplasmic vacuolation in apoptosis-resistant MCL cells

Abstract

Cannabinoid receptors 1 (CB1) and/or 2 (CB2) are overexpressed in many types of human malignancies including mantle cell lymphoma (MCL). Agonists to CB1 and CB2 promote ceramide de novo synthesis, p38–mitogen-activated protein kinase-dependent activation of caspase-3 and apoptotic cell death in most MCLs. However, in this report we describe that in some MCLs the response to treatment with cannabinoids decreased cell viability as assessed by metabolic activity but did not involve the caspase-3 cascade or loss of plasma membrane integrity. Both primary cells from one MCL patient and the MCL cell line Granta519 responded to treatment with cannabinoids by formation of cycloheximide-sensitive cytoplasmic vacuoles, but did not enter apoptosis. The persistent expression of mammalian homolog of Atg8 with microtubule-associated protein-1 light chain-3 II (LC3 II) and p62, as well as the lack of protection from chloroquine, indicates that lysosomal degradation is not involved in this cytoplasmic vacuolation process, distinguishing from classical autophagy. Transmission electron microscopy images and immunofluorescence staining of endoplasmic reticulum (ER) chaperone calreticulin showed that the vacuoles were of ER origin and that chromatin remained normal. These features resemble paraptosis-like cell death—a third type of a programmed cell death not previously described in response to cannabinoids.

Combined Antiproliferative Effects of the Aminoalkylindole WIN55,212-2 and Radiation in Breast Cancer Cells

“…This conclusion is further supported by the observation that WIN2 was also active in 4T1 cells that do not express either the CB 1 or CB 2 receptors (McKallip et al, 2005). Likewise, in studies in melanoma cells and mantle cell lymphoma, WIN2 was shown to act through a noncannabinoid receptor mechanism (Scuderi et al, 2011;Wasik et al, 2011). Our findings are somewhat distinct from those of Qamri et al (2009) in which CB 1 and CB 2 antagonists prevented the antiproliferative effects of WIN2 in MDA-MB231 and MDA-MB468 breast cancer cells.…”

“…A preponderance of studies in the literature investigating the effects of cannabinoids on cancer cells have been performed under low-serum conditions (Carracedo et al, 2006;Salazar et al, 2009;McAllister et al, 2011;Wasik et al, 2011). In contrast, the experiments presented in the present work were performed using media containing 10% serum.…”

“…The results of preclinical trials suggest that these agents may prove to be of use for patients experiencing nausea and vomiting due to radiation therapy (Darmani et al, 2007). Cannabinoids are also known to suppress growth or promote cell death in a variety of cancer cell lines, including glioma, pancreatic, melanoma, lymphoma, lung, and breast (Carracedo et al, 2006;Qamri et al, 2009;Salazar et al, 2009;McAllister et al, 2011;Preet et al, 2011;Scuderi et al, 2011;Wasik et al, 2011). Given that cannabinoid-based drugs are used for suppression of nausea and for appetite stimulation in patients with cancer, as well as their potential utility as adjunctive treatments along with conventional therapies such as radiation, the present studies were initiated to determine whether cannabinoids might augment the antiproliferative actions of radiation in breast tumor cells.…”

“…It is noteworthy that WIN2 suppresses the growth of melanoma, mantle cell lymphoma, non-small cell lung cancer, and breast cancer cell lines (Qamri et al, 2009;Preet et al, 2011;Scuderi et al, 2011;Wasik et al, 2011), as well as suppressing radiation-induced emesis in the least shrew (Darmani et al, 2007) and producing antinociceptive actions in rodent models of cancer pain (Guerrero et al, 2008). Despite its prevalent use as a cannabinoid pharmacological tool, WIN2 has yet to be examined for potential interactions with radiation in terms of tumor growth effects, despite the fact that radiation has been a mainstay of cancer therapy for decades.…”

Cannabinoids as therapeutic agents in cancer: current status and future implications

“…In contrast, cannabinoids decreased cell viability as assessed by metabolic activity. The persistent expression of mammalian homolog of Atg8 with microtubule-associated protein-1 light chain-3 II (LC3 II) and p62, as well as the lack of protection from chloroquine, indicates that lysosomal degradation is not involved in this cytoplasmic vacuolation process, distinguishing from classical autophagy [119]. Paraptosis-like cell death-a third type of a programmed cell death occurred in response to cannabinoids [119].…”