Anti-HIV Activity of Cucurbitacin-D against Cigarette Smoke Condensate-Induced HIV Replication in the U1 Macrophages

Chemodietary agents are emerging as promising adjuvant therapies in treating various disease conditions. However, there are no adjuvant therapies available to minimize the neurotoxicity of currently existing antiretroviral drugs (ARVs). In this study, we investigated the anti-HIV effect of a chemodietary agent, Cucurbitacin-D (Cur-D), in HIV-infected macrophages using an in-vitro blood–brain barrier (BBB) model. Since tobacco smoking is prevalent in the HIV population, and it exacerbates HIV replication, we also tested the effect of Cur-D against cigarette smoke condensate (CSC)-induced HIV replication. Our results showed that Cur-D treatment reduces the viral load in a dose-dependent (0–1 µM) manner without causing significant toxicity at <1 µM concentration. Further, a daily dose of Cur-D (0.1 µM) not only reduced p24 in control conditions, but also reduced CSC (10 µg/mL)-induced p24 in U1 cells. Similarly, Cur-D (single dose of 0.4 µM) significantly reduced the CSC (single dose of 40 µg/mL)-induced HIV replication across the BBB model. In addition, treatment with Cur-D reduced the level of pro-inflammatory cytokine IL-1β. Therefore, Cur-D, as an adjuvant therapy, may be used not only to suppress HIV in the brain, but also to reduce the CNS toxicity of currently existing ARVs.

HPMA-Based Copolymers Carrying STAT3 Inhibitor Cucurbitacin-D as Stimulus-Sensitive Nanomedicines for Oncotherapy

The study describes the synthesis, physicochemical properties, and biological evaluation of polymer therapeutics based on N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers intended for a tumor-targeted immuno-oncotherapy. Water-soluble linear and cholesterol-containing HPMA precursors were synthesized using controlled reversible addition–fragmentation chain transfer polymerization to reach molecular weight Mn about 2 × 104 g·mol−1 and low dispersity. These linear or self-assembled micellar conjugates, containing immunomodulatory agent cucurbitacin-D (CuD) or the anticancer drug doxorubicin (Dox) covalently bound by the hydrolytically degradable hydrazone bond, showed a hydrodynamic size of 10–30 nm in aqueous solutions. The CuD-containing conjugates were stable in conditions mimicking blood. Importantly, a massive release of active CuD in buffer mimicking the acidic tumor environment was observed. In vitro, both the linear (LP-CuD) and the micellar (MP-CuD) conjugates carrying CuD showed cytostatic/cytotoxic activity against several cancer cell lines. In a murine metastatic and difficult-to-treat 4T1 mammary carcinoma, only LP-CuD showed an anticancer effect. Indeed, the co-treatment with Dox-containing micellar polymer conjugate and LP-CuD showed potentiation of the anticancer effect. The results indicate that the binding of CuD, characterized by prominent hydrophobic nature and low bioavailability, to the polymer carrier allows a safe and effective delivery. Therefore, the conjugate could serve as a potential component of immuno-oncotherapy schemes within the next preclinical evaluation.

Cytotoxic Activity of 2-O-β-glucopyranosil Cucurbitacin D from Benalu Batu (Begonia sp.) Growing in Morowali, Central Sulawesi

Benalu batu (Begonia sp.) had been used traditionally as an anticancer medicinal plant by Wana tribe in Morowali, Central Sulawesi, This study aims to evaluate the cytotoxic activity of 2-O-β-glucopyranosil cucurbitacin D, isolated from the ethyl acetate soluble fraction of Benalu batu (Begonia sp.) and to determine its action on apoptosis induction. Benalu batu (Begonia sp.) herb was extracted by maceration using ethanol 96% as a solvent. Vacuum liquid column chromatography and preparative thin layer chromatography have been applied on fractionation and isolation of the compound. The structure elucidation was performed by extensive analysis of 1D/2D nuclear magnetic resonance (NMR) and Mass Spectrophotometer (MS). Cytotoxic activity against human breast adenocarcinoma (MCF-7) and human colon colorectal carcinoma (HCT-116) cell lines were performed by 5-diphenyltetrazolium bromide (MTT) method. Annexin V-FITC assay was employed to determine the apoptosis induction. 2-O-β-glucopyranosil cucurbitacin D showed potent cytotoxic activity against MCF-7 and HCT-116 with the IC50 of 19.913 and 0.002 μg/mL, respectively. Annexin V-FITC assay clearly exhibited the cytotoxic mechanism on MCF-7 and HCT-116 via apoptosis induction with a significant percentage of early and late apoptosis of 75.8 and 78.4%, respectively. This study reveals the potential cytotoxic activity of 2-O-β-glucopyranosil cucurbitacin D isolated from Benalu batu and its mechanism via apoptosis induction.

Novel Mechanistic Insight into the Anticancer Activity of Cucurbitacin D against Pancreatic Cancer (Cuc D Attenuates Pancreatic Cancer)

Pancreatic cancer (PanCa) is one of the leading causes of death from cancer in the United States. The current standard treatment for pancreatic cancer is gemcitabine, but its success is poor due to the emergence of drug resistance. Natural products have been widely investigated as potential candidates in cancer therapies, and cucurbitacin D (Cuc D) has shown excellent anticancer properties in various models. However, there is no report on the therapeutic effect of Cuc D in PanCa. In the present study, we investigated the effects of the Cuc D on PanCa cells in vitro and in vivo. Cuc D inhibited the viability of PanCa cells in a dose and time dependent manner, as evident by MTS assays. Furthermore, Cuc D treatment suppressed the colony formation, arrest cell cycle, and decreased the invasion and migration of PanCa cells. Notably, our findings suggest that mucin 13 (MUC13) is down-regulated upon Cuc D treatment, as demonstrated by Western blot and qPCR analyses. Furthermore, we report that the treatment with Cuc D restores miR-145 expression in PanCa cells/tissues. Cuc D treatment suppresses the proliferation of gemcitabine resistant PanCa cells and inhibits RRM1/2 expression. Treatment with Cuc D effectively inhibited the growth of xenograft tumors. Taken together, Cuc D could be utilized as a novel therapeutic agents for the treatment/sensitization of PanCa.

Simultaneous isolation and purification of cucurbitacin D and I from Ecballium elaterium (l.) A. Rich fruit juice

The objective of this study was to develop a rapid, economic, and efficient method for simultaneous selective isolation, separation, and purification of cucurbitacin D and I from Ecballium elaterium (L.) A. Rich fruit juice via reversed-phase flash chromatography combined with HPLC. The chloroform extract of the fruit juice was fractionated with flash chromatography using a chloroform, acetone and methanol solvent combination at a 5 ml/min flow rate. Then, a validated HPLC method was utilized for purification of the two targeted cucurbitacins. Cucurbitacin D and I were collected automatically by the fraction collector. The fractions containing the same compounds were pooled and lyophilized. The purified cucurbitacin D and I compounds were identified by NMR, LC-MS, and UV spectra analysis. The results suggest that the applied procedure is simple, quick, and highly efficient. The HPLC method was found to be linear, accurate, precise and rugged for the quantification of the cucurbitacins studied.

Cucurbitacin D Reprograms Glucose Metabolic Network in Prostate Cancer

Prostate cancer (PrCa) metastasis is the major cause of mortality and morbidity among men. Metastatic PrCa cells are typically adopted for aberrant glucose metabolism. Thus, chemophores that reprogram altered glucose metabolic machinery in cancer cells can be useful agent for the repression of PrCa metastasis. Herein, we report that cucurbitacin D (Cuc D) effectively inhibits glucose uptake and lactate production in metastatic PrCa cells via modulating glucose metabolism. This metabolic shift by Cuc D was correlated with decreased expression of GLUT1 by its direct binding as suggested by its proficient molecular docking (binding energy −8.5 kcal/mol). Cuc D treatment also altered the expression of key oncogenic proteins and miR-132 that are known to be involved in glucose metabolism. Cuc D (0.1 to 1 µM) treatment inhibited tumorigenic and metastatic potential of human PrCa cells via inducing apoptosis and cell cycle arrest in G2/M phase. Cuc D treatment also showed inhibition of tumor growth in PrCa xenograft mouse model with concomitant decrease in the expression of GLUT1, PCNA and restoration of miR-132. These results suggest that Cuc D is a novel modulator of glucose metabolism and could be a promising therapeutic modality for the attenuation of PrCa metastasis.