[Medicinal chemistry and pharmacology focused on cannabidiol, a major component of the fiber-type cannabis]

An overview on synthetic and biological activities of cannabidiol (CBD) and its derivatives

(-)-Cannabidiol is a class of non-psychoactive plant cannabinoids derived from cannabis plants. Currently, Epidiolex (Cannabidiol) has been approved by the FDA for the treatment of two rare and severe forms of epilepsy related diseases, namely Lennox-Gastaut syndrome (LGS) and Dravet (DS). In addition, Cannabidiol and its structural analogues have received increasing attention due to their potential therapeutic effects such as neuroprotection, anti-epilepsy, anti-inflammation, anti-anxiety, and anti-cancer. Based on literature review, no comprehensive reviews on the synthesis of Cannabidiol and its derivatives have been found in recent years. Therefore, this article summarizes the published synthesis methods of Cannabidiol and the synthesis routes of Cannabidiol derivatives, and introduces the biological activities of some Cannabidiol analogues that have been studied extensively and have significant activities.

Cannabidiolic acid dampens the expression of cyclooxygenase-2 in MDA-MB-231 breast cancer cells: Possible implication of the peroxisome proliferator-activated receptor β/δ abrogation

A growing body of experimental evidence strongly suggests that cannabidiolic acid (CBDA), a major component of the fiber-type cannabis plant, exerts a variety of biological activities. We have reported that CBDA can abrogate cyclooxygenase-2 (COX-2) expression and its enzymatic activity. It is established that aberrant expression of COX-2 correlates with the degree of malignancy in breast cancer. Although the reduction of COX-2 expression by CBDA offers an attractive medicinal application, the molecular mechanisms underlying these effects have not fully been established. It has been reported that COX-2 expression is positively controlled by peroxisome proliferator-activated receptor β/δ (PPARβ/δ) in some cancerous cells, although there is "no" modulatory element for PPARβ/δ on the COX-2 promoter. No previous studies have examined whether an interaction between PPARβ/δ-mediated signaling and COX-2 expression exists in MDA-MB-231 cells. We confirmed, for the first time, that COX-2 expression is positively modulated by PPARβ/δ-mediated signaling in MDA-MB-231 cells. CBDA inhibits PPARβ/δ-mediated transcriptional activation stimulated by the PPARβ/δ-specific agonist, GW501516. Furthermore, the disappearance of cellular actin stress fibers, a hallmark of PPARβ/δ and COX-2 pathway activation, as evoked by the GW501516, was effectively reversed by CBDA. Activator protein-1 (AP-1)-driven transcriptional activity directly involved in the regulation of COX-2 was abrogated by the PPARβ/δ-specific inverse agonists (GSK0660/ST-247). Thus, it is implicated that there is positive interaction between PPARβ/δ and AP-1 in regulation of COX-2. These data support the concept that CBDA is a functional down-regulator of COX-2 through the abrogation of PPARβ/δ-related signaling, at least in part, in MDA-MB-231 cells.

Future Aspects for Cannabinoids in Breast Cancer Therapy

Cannabinoids (CBs) from Cannabis sativa provide relief for tumor-associated symptoms (including nausea, anorexia, and neuropathic pain) in the palliative treatment of cancer patients. Additionally, they may decelerate tumor progression in breast cancer patients. Indeed, the psychoactive delta-9-tetrahydrocannabinol (THC), non-psychoactive cannabidiol (CBD) and other CBs inhibited disease progression in breast cancer models. The effects of CBs on signaling pathways in cancer cells are conferred via G-protein coupled CB-receptors (CB-Rs), CB1-R and CB2-R, but also via other receptors, and in a receptor-independent way. THC is a partial agonist for CB1-R and CB2-R; CBD is an inverse agonist for both. In breast cancer, CB1-R expression is moderate, but CB2-R expression is high, which is related to tumor aggressiveness. CBs block cell cycle progression and cell growth and induce cancer cell apoptosis by inhibiting constitutive active pro-oncogenic signaling pathways, such as the extracellular-signal-regulated kinase pathway. They reduce angiogenesis and tumor metastasis in animal breast cancer models. CBs are not only active against estrogen receptor-positive, but also against estrogen-resistant breast cancer cells. In human epidermal growth factor receptor 2-positive and triple-negative breast cancer cells, blocking protein kinase B- and cyclooxygenase-2 signaling via CB2-R prevents tumor progression and metastasis. Furthermore, selective estrogen receptor modulators (SERMs), including tamoxifen, bind to CB-Rs; this process may contribute to the growth inhibitory effect of SERMs in cancer cells lacking the estrogen receptor. In summary, CBs are already administered to breast cancer patients at advanced stages of the disease, but they might also be effective at earlier stages to decelerate tumor progression.

Cannabidiol-2',6'-dimethyl ether stimulates body weight gain in apolipoprotein E-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice

The biological activities of cannabidiol (CBD), a major non-psychotropic constituent of the fiber-type cannabis plant, have been examined in detail (e.g., CBD modulation of body weight in mice and rats). However, few studies have investigated the biological activities of cannabidiol-2',6'-dimethyl ether (CBDD), a dimethyl ether derivative of the parent CBD. We herein focused on the effects of CBDD on body weight changes in mice, and demonstrated that it stimulated body weight gain in apolipoprotein E (ApoE)-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice, especially between 10 and 20 weeks of age.

Down-regulation of cyclooxygenase-2 (COX-2) by cannabidiolic acid in human breast cancer cells

Metastases are known to be responsible for approximately 90% of breast cancer-related deaths. Cyclooxygenase-2 (COX-2) is involved not only in inflammatory processes, but also in the metastasis of cancer cells; it is expressed in 40% of human invasive breast cancers. To comprehensively analyze the effects of cannabidiolic acid (CBDA), a selective COX-2 inhibitor found in the fiber-type cannabis plant (Takeda et al., 2008), on COX-2 expression and the genes involved in metastasis, we performed a DNA microarray analysis of human breast cancer MDA-MB-231 cells, which are invasive breast cancer cells that express high levels of COX-2, treated with CBDA for 48 hr at 25 µM. The results obtained revealed that COX-2 and Id-1, a positive regulator of breast cancer metastasis, were down-regulated (0.19-fold and 0.52-fold, respectively), while SHARP1 (or BHLHE41), a suppressor of breast cancer metastasis, was up-regulated (1.72-fold) and CHIP (or STUB1) was unaffected (1.03-fold). These changes were confirmed by real-time RT-PCR analyses. Taken together, the results obtained here demonstrated that i) CBDA had dual inhibitory effects on COX-2 through down-regulation and enzyme inhibition, and ii) CBDA may possess the ability to suppress genes that are positively involved in the metastasis of cancer cells in vitro.