Розмарин и рак Rosmarinus officinalis & cancer Научные исследования

Discussion

In this particular study, we evaluated rosemary extract standardized to carnosic acid for decreasing prostate cancer cell viability. The rationale for evaluating a complex mixture of rosemary polyphenols was several fold [19]. First, several epidemiological studies have reported that rosemary consumption is associated with an overall reduction in cancer incidence [21]. Second, the European Union has approved the use of rosemary extracts for food preservation and has been adopted into the EU food legislation [22]. Third, in the United States rosemary has been categorized by the FDA as “generally recognized as safe” or GRAS (CFR 182.10; 182.20). Fourth, rosemary is widely available as a dietary supplement in the United States. Lastly, it is apparent from our studies as well as others that complex mixtures of polyphenols under certain circumstances can provide a multi-targeted effect compared to individual phytochemicals. Based on these observations as well as our previous evaluation of individual phytochemicals led us to investigate rosemary extract standardized to carnosic acid.

Alterations in the environment surrounding the endoplasmic reticulum have a direct effect on the integrity, structure and function of this organelle [7], [8]. This is especially significant during cancer promotion and progression as there is an increased demand on the protein production of the endoplasmic reticulum to meet the increased metabolic needs of cancer cells. During this process it is evident that there is an increased likelihood of proteins that are misfolded or even unfolded. If left unchecked, these cells will undergo apoptosis. In response, the cell has the capability to address protein instability via the “unfolded protein response” which is controlled by PERK and CHOP, along with several other ER stress proteins [23]. As the cancer cell compensates for this established homeostasis, proteins may fold properly or undergo a controlled degradation thereby increasing cell survival. Evidence by other investigators and ourselves suggests that the use of small molecules to modulate ER stress may delay tumor development, growth, invasion, thereby providing a novel therapeutic strategy [24]. As reported above we observed rosemary extract to modulate ER stress proteins, including CHOP/GADD153. The effects of modulating CHOP/GADD153 can be seen as early as 20 µg/ml of rosemary extract (40% carnosic acid) which approximates to 24 µM of carnosic acid. Based on previous reports of the pharmacokinetic parameters of carnosic acid it would appear that these concentrations are achievable following oral administration [25], however, further work would be required to determine the pharmacokinetic profile in mice [26].

On another front in prostate cancer control it is well known that the androgen receptor has been a target for prostate cancer for a long time. It is becoming increasingly clear that there is a significant shortcoming with targeting the androgen receptor with traditional ligand binding receptor antagonists. First, the role of anti-androgens is often limited because androgen antagonists (e.g. flutamide and bicalutamide) are used to control the initial prostate cancer “flare” [27]. This is often followed by an eventual conversion of prostate cancer to a castration resistant form. The response of the cancer cell to “resist” anti-androgens is correlated with mutations in the androgen receptor that render traditional anti-androgen antagonists ineffective or even counter-productive.

The evidence is overwhelming that the androgen receptor is a valuable target for prostate cancer, however, an alternative strategy should be explored to disrupt the androgen receptor as opposed to traditional antagonists at the ligand binding domain. One approach that has been proposed is targeted degradation of the androgen receptor, however, at present these chemicals are too toxic for in vivo studies. In our study we observed rosemary extract to decrease androgen receptor protein expression at concentrations as low as 20 µg/mL (∼ 24 µM of carnosic acid). Furthermore we observed a significant decrease in secreted prostate specific antigen in LNCaP cells from 11.5 to 2 ng/ml with rosemary extract treatment. The next step was to determine if there was a link between CHOP/GADD153 and decreased androgen receptor with rosemary extract treatment. In both 22Rv1 and LNCaP cells we observed a significant increase in CHOP, however, using siRNA along with rosemary extract treatment we observed a reversal of rosemary extract induced androgen receptor degradation. However, given that CHOP is generally considered a downstream event in the ER stress response as it closely regulates the anti-apoptotic and pro-apoptotic proteins we wanted to evaluate proteins earlier in the ER stress response. Next, we performed siRNA with BiP, an ER stress chaperone, with or without rosemary extract. Interestingly, when cells were treated with BiP siRNA and rosemary extract a reversal of the AR degradation is observed. In regard, to the function of BiP it will go through multiple cycles of binding and releasing a substrate protein through an ATP driven process that will allow the substrate to fold properly [28]. Under those conditions protein disulfide isomerase (PDI) is recruited to reduce, rearrange, and oxidize disulfide bonds until the correct conformation is achieved. Interestingly, prolonged binding of BiP to a protein has been shown to result in proteasomal degradation [29]. Another interesting observation of BiP by others has shown it to be a key regulator of translocon pores in the endoplasmic reticulum [28]. Future work will need to evaluate if rosemary extract is responsible for governing the pore and/or ushering proteins to the proteasome.

Two benign primary PrE cell lines were evaluated to understand if a bisphasic response in ER stress modulation would be observed. In these cells significant upregulation of PERK was observed suggesting that these cells, although from benign regions of the prostate, are at a critical turning point in the carcinogenic process possible as a result of age or field effects [13]. These PrE cells also do not express androgen receptor, which may contribute to the differential response to rosemary extract, resulting in a decrease in PERK expression. This biphasic response further illustrates the complexity of ER stress during prostate carcinogenesis. It is clear that rosemary is an abundant source of a variety of different polyphenolic substances that are different than other well-known natural products and will require a more detailed understanding of how these chemical constituents can contribute to ER stress and androgen receptor degradation [20], [30].

The accumulation of mutations in “normal” cells results in an inability to overcome traditional checkpoints is critical in prostate carcinogenesis. Based on the results described above further work is needed to understand how the individual phytochemicals in rosemary modulate critical targets that regulate the cell cycle and endoplasmic reticulum stress. Especially within prostate cancer it is evident that the androgen receptor which acts as a transcription factor for over 800 genes is a critical component of this process. For this reason, the androgen receptor has been aggressively targeted through androgen receptor antagonists, however, a new approach may be needed to overcome the traditional obstacles that present themselves shortly after therapy initiation. In our studies, we observed rosemary extract to selectively induce ER stress proteins and provide evidence that CHOP/GADD153/BIP is a critical pathway of androgen receptor degradation. Furthermore, these results were also observed in 22Rv1 xenograft mouse tissues following oral administration of rosemary extract. Interestingly, in normal prostate epithelial cells procured from patients at high risk of developing prostate cancer rosemary extract standardized to carnosic acid is observed to decrease ER stress. Further work will be required to evaluate individual diterpenes in modulating ER stress proteins in prostate cancer to further understand how rosemary extract promotes ER stress.

Carnosol, розмарин ингредиент, индуцирует апоптоз в взрослых Т-клеточный лейкоз/лимфома клеток через истощение глутатиона: протеомный подход с использованием флуоресцентных двумерных дифференциальных гель-электрофореза.

Взрослый Т-клеточный лейкоз/лимфома (ATL) является фатальной злокачественных новообразований, вызванных инфекцией с человека Т-лимфотропных вирусов типа 1 и не существует общепринятой лечебной терапии для ATL. Мы искали биологических активных веществ для профилактики и лечения ATL из нескольких видов трав. ATL клеточный рост-ингибирующей активности и апоптоза анализа показали, что carnosol, что это ингредиент, входящий в состав розмарина (Rosmarinus officinalis), индуцированного апоптоза в ATL клеток. Далее, чтобы исследовать апоптоз-индуцирующего механизм carnosol, мы применили протеомный анализ с использованием флуоресцентных двумерных дифференциальных гель-электрофореза и масс-спектрометрии. На протеомный анализ показал, что выражение редуктаз, собравшиеся ферментов гликолитического пути и ферментов пентозофосфатного пути, путь был увеличен в carnosol-обработанных клетках, по сравнению с необработанными клетками. Эти результаты позволяют предположить, что carnosol пострадавших окислительно-восстановительный статус клетки. Кроме того, количественный анализ глутатиона, который играет центральную роль для поддержания внутриклеточного редокс-статуса, указал, что carnosol вызвал снижение глутатиона в клетках. Далее, N-ацетил-L-цистеином, который является предшественником глутатиона, отменено эффективности carnosol. Исходя из этих результатов было высказано предположение, что апоптоз-индуцирующую активность carnosol в ATL клеток, вызванный истощением глутатиона.