Anti-Tumor Effects of Ginsenoside 20(S)-Protopanaxadiol and 1,25-Dihydroxyvitamin D3 Combination in Castration Resistant Prostate Cancer.

In spite of possessing desirable anticancer properties, currently, limited clinical success has been achieved with 20(S)-protopanaxadiol (aPPD) and 1,25-dihydroxyvitamin D3 (calcitriol). This study is designed to evaluate if the combination of aPPD with calcitriol can inhibit human prostate cancer xenograft growth by using nuclear receptor signaling. Athymic male nude mice were utilized to establish an androgen-independent human prostate cancer C4-2 cell castration-resistant prostate cancer (CRPC) xenograft model. Mice were treated orally for six weeks with 70 mg/kg aPPD administered once daily or three times per week with 4 µg/kg calcitriol or in combination or only with vehicle control. Contrary to our expectations, calcitriol treatment alone increased C4-2 tumor growth. However, the addition of calcitriol substantially increased aPPD-mediated tumor growth suppression (76% vs. 53%, combination vs. aPPD alone). The combination treatment significantly increased levels of cleaved caspase-3 apoptotic marker compared to vehicle-treated or aPPD-treated C4-2 tumors. The mechanistic elucidations indicate that tumor inhibition by the aPPD and calcitriol combination was accompanied by elevated vitamin D receptor (VDR) protein expression. In silico data suggest that aPPD weakly binds to the native LBD pocket of VDR. Interestingly, the combination of aPPD and calcitriol activated VDR at a significantly higher level than calcitriol alone and this indicates that aPPD may be an allosteric activator of VDR. Overall, aPPD and calcitriol combination significantly inhibited tumor growth in vivo with no acute or chronic toxic effects in the C4-2 xenograft CRPC nude mice. The involvement of VDR and downstream apoptotic pathways are potential mechanistic routes of antitumor effects of this combination.

Pharmacokinetic interaction of calcitriol with 20(S)-protopanaxadiol in mice: Determined by LC/MS analysis.

The physiological and anti-cancer functions of vitamin D3 are accomplished primarily via 1α,25-dihydroxyvitamin D3 (calcitriol), whereas 20(S)-protopanaxadiol (aPPD) is a ginsenoside, which is isolated from Panax ginseng, with potential anti-cancer benefits. In the present study, we report a pharmacokinetic (PK) herb-nutrient interaction between calcitriol and aPPD in mice. A liquid chromatography mass spectrometry (LC/MS) method was developed using 4-phenyl-1,2,4-triazoline-3,5-dione derivatizing agent and we subsequently used the method to quantitate calcitriol in mouse serum. The limit of quantitation was 0.01 ng/ml which is approximately 100 fold lower than the previously reported assay from our laboratory. Calcitriol PK parameters were determined in non-tumor-bearing or C4-2 human prostate tumor-bearing nude mice following oral co-administration of calcitriol either alone or in combination with aPPD. Mice were pretreated with oral aPPD (70 mg/kg) or vehicle control twice daily for seven consecutive days, followed by a single oral dose of 4 µg/kg calcitriol alone or in combination with aPPD. Our PK results demonstrated that co-administration of calcitriol with aPPD (following pre-treatment with vehicle for seven days) resulted in a 35% increase in the area under the curve (AUC0-24 h) and a 41% increase in the maximum serum concentration (Cmax) compared to the calcitriol only group. aPPD therefore significantly increased calcitriol serum exposure. We also saw a reduction in the time required to reach Cmax. In contrast, calcitriol PK in mice co-administered with calcitriol and aPPD as well as those pretreated seven consecutive days with aPPD was no different than that determined for the mice that received vehicle for seven days as pre-treatment. Co-administration of calcitriol with aPPD therefore could increase health benefits of vitamin D3, however any increased risk of hypercalcemia, resulting from this combination approach, requires further investigation. Lastly, we surmise that a cytochrome P450 inhibition-based mechanism may contribute to the observed PK interaction.

Yes, not now, or never: an analysis of reasons for refusing or accepting emergency department-based take-home naloxone.

OBJECTIVE: Take-home naloxone (THN) reduces deaths from opioid overdose. To increase THN distribution to at-risk emergency department (ED) patients, we explored reasons for patients' refusing or accepting THN. METHODS: In an urban teaching hospital ED, we identified high opioid overdose risk patients according to pre-specified criteria. We offered eligible patients THN and participation in researcher-administered surveys, which inquired about reasons to refuse or accept THN and about THN dispensing location preferences. We analyzed refusal and acceptance reasons in open-ended responses, grouped reasons into categories (absolute versus conditional refusals,) then searched for associations between patient characteristics and reasons. RESULTS: Of 247 patients offered THN, 193 (78.1%) provided reasons for their decision. Of those included, 69 (35.2%) were female, 91 (47.2%) were under age 40, 61 (31.6%) were homeless, 144 (74.6%) reported injection drug use (IDU), and 131 (67.9%) accepted THN. Of 62 patients refusing THN, 19 (30.7%) felt "not at risk" for overdose, while 28 (45.2%) gave conditional refusal reasons: "too sick," "in a rush," or preference to get THN elsewhere. Non-IDU was associated with stating "not at risk," while IDU, homelessness, and age under 40 were associated with conditional refusals. Among acceptances, 86 (65.7%) mentioned saving others as a reason. Most respondents preferred other dispensing locations beside the ED, whether or not they accepted ED THN. CONCLUSION: ED patients refusing THN felt "not at risk" for overdose or felt their ED visit was not the right time or place for THN. Most accepting THN wanted to save others.

20(S)-protopanaxadiol regio-selectively targets androgen receptor: anticancer effects in castration-resistant prostate tumors.

We have explored the effects of 20(S)-protopanaxadiol (aPPD), a naturally derived ginsenoside, against androgen receptor (AR) positive castration resistant prostate cancer (CRPC) xenograft tumors and have examined its interactions with AR. In silico docking studies for aPPD binding to AR, alongside transactivation bioassays and in vivo efficacy studies were carried out in the castration-resistant C4-2 xenograft model. Immunohistochemical (IHC) and Western blot analyses followed by evaluation of AR, apoptotic, cell cycle and proliferative markers in excised tumors was performed. The growth of established CRPC tumors was inhibited by 53% with aPPD and a corresponding decrease in serum PSA was seen compared to controls. The IHC data revealed that Ki-67 was significantly lower for aPPD treated tumors and was associated with elevated p21 and cleaved caspase-3 expression, compared to vehicle treatment. Furthermore, aPPD decreased AR protein expression in xenograft tumors, while significantly upregulating p27 and Bax protein levels. In vitro data supporting this suggests that aPPD binds to and significantly inhibits the N-terminal or the DNA binding domains of AR. The AR androgen binding site docking score for androgen (dihydrotestosterone) was -11.1, while that of aPPD was -7.1. The novel findings described herein indicate aPPD potently inhibits PCa in vivo partly via inhibition of a site on the AR N-terminal domain. This manifested as cell cycle arrest and concurrent induction of apoptosis via an increase in Bax, cleaved-caspase-3, p27 and p21 expression.

Factors Associated With Participation in an Emergency Department-Based Take-Home Naloxone Program for At-Risk Opioid Users.

STUDY OBJECTIVE: Although the World Health Organization recommends take-home naloxone to address the increasing global burden of opioid-related deaths, few emergency departments (EDs) offer a take-home naloxone program. We seek to determine the take-home naloxone acceptance rate among ED patients at high risk of opioid overdose and to examine factors associated with acceptance. METHODS: At a single urban ED, consecutive eligible patients at risk of opioid overdose were invited to complete a survey about opioid use, overdose experience, and take-home naloxone awareness, and then offered take-home naloxone. The primary outcome was acceptance of take-home naloxone, including the kit and standardized patient training. Univariate and multivariable logistic analyses were used to evaluate factors associated with acceptance. RESULTS: Of 241 eligible patients approached, 201 (83.4%) completed the questionnaire. Three-quarters of respondents used injection drugs, 37% were women, and 26% identified as "Indigenous." Of 201 respondents, 137 (68.2%; 95% confidence interval [CI] 61.7% to 74.7%) accepted take-home naloxone. Multivariable analysis revealed that factors associated with take-home naloxone acceptance included witnessing overdose in others (odds ratio [OR] 4.77; 95% CI 2.25 to 10.09), concern about own overdose death (OR 3.71; 95% CI 1.34 to 10.23), female sex (OR 2.50; 95% CI 1.21 to 5.17), and injection drug use (OR 2.22; 95% CI 1.06 to 4.67). CONCLUSION: A two-thirds ED take-home naloxone acceptance rate in patients using opioids should encourage all EDs to dispense take-home naloxone. ED-based take-home naloxone programs have the potential to improve access to take-home naloxone and awareness in individuals most vulnerable to overdoses.