Evidence of a novel docetaxel sensitizer, garlic-derived S-allylmercaptocysteine, as a treatment option for hormone refractory prostate cancer

Therapy resistance in prostate cancer: mechanism, signaling and reversal strategies

Prostate cancer (PC) depicts a major health challenge all over the globe due to its complexities in the treatment and diverse clinical trajectories. Even in the advances in the modern treatment strategies, the spectrum of resistance to the therapies continues to be a significant challenge. This review comprehensively examines the underlying mechanisms of the therapy resistance occurred in PC, focusing on both the tumor microenvironment and the signaling pathways implicated in the resistance. Tumor microenvironment comprises of stromal and epithelial cells, which influences tumor growth, response to therapy and progression. Mechanisms such as microenvironmental epithelial-mesenchymal transition (EMT), anoikis suppression and stimulation of angiogenesis results in therapy resistance. Moreover, dysregulation of signaling pathways including androgen receptor (AR), mammalian target of rapamycin/phosphoinositide 3 kinase/AKT (mTOR/PI3K/AKT), DNA damage repair and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways drive therapy resistance by promoting tumor survival and proliferation. Understanding these molecular pathways is important for developing targeted therapeutic interventions which overcomes resistance. In conclusion, a complete grasp of mechanisms and pathways underlying medication resistance in PC is important for the development of individualized treatment plans and enhancements of clinical outcomes. By studying and understanding the complex mechanisms of signaling pathways and microenvironmental factors contributing to therapy resistance, this study focuses and aims to guide the development of innovative therapeutic approaches to effectively overcome the PC progression and improve the survival rate of patients.

Neutralizing tumor-related inflammation and reprogramming of cancer-associated fibroblasts by Curcumin in breast cancer therapy

Tumor-associated inflammation plays a vital role in cancer progression. Among the various stromal cells, cancer-associated fibroblasts are promising targets for cancer therapy. Several reports have indicated potent anti-inflammatory effects attributed to Curcumin. This study aimed to investigate whether inhibiting the inflammatory function of cancer-associated fibroblasts (CAFs) with Curcumin can restore anticancer immune responses. CAFs were isolated from breast cancer tissues, treated with Curcumin, and co-cultured with patients' PBMCs to evaluate gene expression and cytokine production alterations. Blood and breast tumor tissue samples were obtained from 12 breast cancer patients with stage II/III invasive ductal carcinoma. Fibroblast Activation Protein (FAP) + CAFs were extracted from tumor tissue, treated with 10 μM Curcumin, and co-cultured with corresponding PBMCs. The expression of smooth muscle actin-alpha (α-SMA), Cyclooxygenase-2(COX-2), production of PGE2, and immune cell cytokines were evaluated using Real-Time PCR and ELISA, respectively. Analyzes showed that treatment with Curcumin decreased the expression of genes α-SMA and COX-2 and the production of PGE2 in CAFs. In PBMCs co-cultured with Curcumin-treated CAFs, the expression of FoxP3 decreased along with the production of TGF-β, IL-10, and IL-4. An increase in IFN-γ production was observed that followed by increased T-bet expression. According to our results, Curcumin could reprogram the pro-tumor phenotype of CAFs and increase the anti-tumor phenotype in PBMCs. Thus, CAFs, as a component of the tumor microenvironment, are a suitable target for combination immunotherapies of breast cancer.

From Natural Sources to Synthetic Derivatives: The Allyl Motif as a Powerful Tool for Fragment-Based Design in Cancer Treatment

Since the beginning of history, natural products have been an abundant source of bioactive molecules for the treatment of different diseases, including cancer. Many allyl derivatives, which have shown anticancer activity both in vitro and in vivo in a large number of cancers, are bioactive molecules found in garlic, cinnamon, nutmeg, or mustard. In addition, synthetic products containing allyl fragments have been developed showing potent anticancer properties. Of particular note is the allyl derivative 17-AAG, which has been evaluated in Phase I and Phase II/III clinical trials for the treatment of multiple myeloma, metastatic melanoma, renal cancer, and breast cancer. In this Perspective, we compile extensive literature evidence with descriptions and discussions of the most recent advances in different natural and synthetic allyl derivatives that could generate cancer drug candidates in the near future.

Capric Acid Behaves Agonistic Effect on Calcitriol to Control Inflammatory Mediators in Colon Cancer Cells

Inflammation prompts cancer development and promotes all stages of tumorigenesis. Calcitriol is a nutraceutical essential regulator for host health benefits. However, the influence of calcitriol on inflammatory mediators involved in cancer cells is not clear. This study aimed to assess the sensitivity of calcitriol alone and combined with capric acid, and identify the possible influence of calcitriol on inflammatory mediators. The colorectal cancer cell line (HCT116) was induced by LPS/TNF-α and the inflammation and metastatic mediators (IL-1β, IL-6, IL-17) were quantified in calcitriol and capric acid supplemented colon cancer cells. The mRNA and protein expression of MMP-2, NF-κB and COX-2 were quantified. The significant reduction in MMP-2 expression was confirmed at combination treatment by zymogram analysis. Our findings demonstrated the anti-inflammatory and anti-metastatic potentials of capric acid and calcitriol in individual exposure in a combination of human colon cancer cell lines (HCT116). These abilities may be due to the inhibition of COX-2 mediators and NF-κB transcription factor and reciprocally regulated MMP-2 and MMP-9 signaling pathways. These findings elucidate the activation of COX-2 and NF-κB via disruption of the cellular outer matrix could be considered a novel molecular target suitable for colorectal cancer therapy. This study confirmed that capric acid activates calcitriol sensitization in colon cancer cells and could be used as a successful supplement for intestinal diseases and colon aberrations.

Black Garlic and Its Bioactive Compounds on Human Health Diseases: A Review

Black garlic (BG) is a form of aged garlic obtained from raw garlic (Allium sativum) via Millard reaction under high temperature (60-90 °C) and humidity (70-90%) for a period of time. Several studies reported higher contents of water-soluble antioxidants compounds (S-allyl cysteine, S-allyl-mercapto cysteine), 5-hydroxymethylfurfural, organosulfur compounds, polyphenol, volatile compounds, and products of other Millard reactions compared to fresh garlic after the thermal processing. Recent studies have demonstrated that BG and its bioactive compounds possess a wide range of biological activities and pharmacological properties that preserve and show better efficacy in preventing different types of diseases. Most of these benefits can be attributed to its anti-oxidation, anti-inflammation, anti-obesity, hepatoprotection, hypolipidemia, anti-cancer, anti-allergy, immunomodulation, nephroprotection, cardiovascular protection, and neuroprotection. Substantial studies have been conducted on BG and its components against different common human diseases in the last few decades. Still, a lot of research is ongoing to find out the therapeutic effects of BG. Thus, in this review, we summarized the pre-clinical and clinical studies of BG and its bioactive compounds on human health along with diverse bioactivity, a related mode of action, and also future challenges.

Can diallyl trisulfide, a dietary garlic-derived compound, activate ferroptosis to overcome therapy resistance in prostate cancer?

BACKGROUND

Therapy resistance is the underlying reason for poor outcome in prostate cancer (PCa) patients. Diallyl trisulfide (DATS) is an organosulfur compound present in garlic. DATS has been shown to target PCa cells by induction of apoptosis, increase in the production of reactive oxygen species, degradation of ferritin protein and increase in the labile iron (Fe) pool.

AIM

We hypothesize that DATS could induce ferroptosis, an Fe-dependent, unique non-apoptotic form of regulated cell death to eliminate therapy resistance encountered by PCa patients.

METHODS

In vitro and in vivo studies should be performed to test the hypothesis.

RESULTS

As per the hypothesis, DATS would eliminate apoptotic resistance via inducing ferroptosis.

CONCLUSION

Since apoptosis resistance has been reported to be the underlying mechanism of therapy resistance in PCa, DATS could be used to effectively target PCa cells by overcoming apoptosis resistance and inducing ferroptosis-mediated cell death of PCa cells.

Leukotrienes in Tumor-Associated Inflammation

Leukotrienes are biologically active eicosanoid lipid mediators that originate from oxidative metabolism of arachidonic acid. Biosynthesis of leukotrienes involves a set of soluble and membrane-bound enzymes that constitute a machinery complex primarily expressed by cells of myeloid origin. Leukotrienes and their synthetic enzymes are critical immune modulators for leukocyte migration. Increased concentrations of leukotrienes are implicated in a number of inflammatory disorders. More recent work indicates that leukotrienes may also interact with a variety of tissue cells, contributing to the low-grade inflammation of cardiovascular, neurodegenerative, and metabolic conditions, as well as that of cancer. Leukotriene signaling contributes to the active tumor microenvironment, promoting tumor growth and resistance to immunotherapy. This review summarizes recent insights into the intricate roles of leukotrienes in promoting tumor growth and metastasis through shaping the tumor microenvironment. The emerging possibilities for pharmacological targeting of leukotriene signaling in tumor metastasis are considered.

Determination of S-Allylmercaptocysteine in Rat Plasma by LC-MS/MS and its Application to a Pharmacokinetics Study

In this work, a rapid, simple, sensitive and specific LC-MS/MS method was developed and validated for the quantification of S-Allylmercaptocysteine (SAMC) in plasma. After a simple sample procedure by one step protein precipitation with acetontrile, the samples were separated on Gemini-NX C18 column (2.1 mm i.d. 150 mm, 3 μm, Phenomenex). The mobile phase was composed of water-acetonitrile (20:80, v/v) at an isocratic flow rate of 0.3 mL/min. The developed method was validated based on the International Conference on Harmonization (ICH) guidelines. The results show that the method had satisfactory specificity, precision and accuracy in a linear range of 50-3,000 ng/mL for SAMC. The precision conformed to the acceptance criteria, and the lower limit of quantification was 50 ng/mL for the analyte. The plasma samples stored for 10 days or after two freeze-thaw cycles (-80°C) were stable. This method was successfully applied to a pharmacokinetics study of SAMC in rats. It was found that SAMC metabolized very quickly in rats and its plasma half-life was less than 5 min.

Anti-Inflammatory Drugs as Anticancer Agents

Inflammation is strictly associated with cancer and plays a key role in tumor development and progression. Several epidemiological studies have demonstrated that inflammation can predispose to tumors, therefore targeting inflammation and the molecules involved in the inflammatory process could represent a good strategy for cancer prevention and therapy. In the past, several clinical studies have demonstrated that many anti-inflammatory agents, including non-steroidal anti-inflammatory drugs (NSAIDs), are able to interfere with the tumor microenvironment by reducing cell migration and increasing apoptosis and chemo-sensitivity. This review focuses on the link between inflammation and cancer by describing the anti-inflammatory agents used in cancer therapy, and their mechanisms of action, emphasizing the use of novel anti-inflammatory agents with significant anticancer activity.

Anti-cancer activities of S-allylmercaptocysteine from aged garlic

While most types of malignancies remain recalcitrant to treatment, application of natural products or their analogs in daily life has offered some hopes as an effective prophylaxis against cancer onset and progression in the past decades. Emerging evidence supports a link between garlic consumption and decreased cancer incidence. Notably, aged garlic extract (AGE) exhibits stronger anti-cancer activities than that of fresh garlic, by virtue of enrichment of several AGE-specific organosulfur compounds, including S-allylmercaptocysteine (SAMC). In this review, we summarize the up-to-date mechanistic pathways associated with the anti-proliferative, anti-metastatic and pro-apoptotic effects of SAMC in various cancer models. Based upon the proven safety and improved understanding on its anti-neoplastic properties, SAMC has gained recognition as a promising daily food supplement for cancer prevention or management.

Fibroblast activation proteins-α suppress tumor immunity by regulating T cells and tumor-associated macrophages

Fibroblast activation protein-α (FAPα) is a type-II cell-surface-bound integral transmembrane serine protease and selectively overexpressed by tumor-associated stromal fibroblasts (TAFs), which are the main components in the tumor microenvironment, in >90% of malignant epithelial carcinomas. FAPα regulates the immunosuppression of tumor cells in the tumor microenvironment. Regulatory T cells (Tregs) and tumor-associated macrophages (TAMs) are the major immunosuppressive cells in the tumor microenvironment. However, the effect of FAPα on Tregs and TAMs is unknown. The non-enzymatic function of FAPα on Treg and TAM was investigated. In this study, we confirm that FAPα can promote the generation of Tregs and TAMs, which suggests that FAPα plays a immunosuppressive role in the tumor microenvironment and provides evidence for FAP α as a potent immunotherapeutic target for cancer.

Epigenetic Upregulation of Metallothionein 2A by Diallyl Trisulfide Enhances Chemosensitivity of Human Gastric Cancer Cells to Docetaxel Through Attenuating NF-κB Activation

AIMS

Metallothionein 2A (MT2A) and nuclear factor-kappaB (NF-κB) are both involved in carcinogenesis and cancer chemosensitivity. We previously showed decreased expression of MT2A and IκB-α in human gastric cancer (GC) associated with poor prognosis of GC patients. The present study investigated the effect of diallyl trisulfide (DATS), a garlic-derived compound, and docetaxel (DOC) on regulation of MT2A in relation to NF-κB in GC cells.

RESULTS

DATS attenuated NF-κB signaling in GC cells, resulting in G2/M cell cycle arrest and apoptosis, culminating in the inhibition of cell proliferation and tumorigenesis in nude mice. The anti-GC effect of DATS was attributable to its capacity to epigenetically upregulate MT2A, which in turn enhanced transcription of IκB-α to suppress NF-κB activation in GC cells. The combination of DATS with DOC exhibited a synergistic anti-GC activity accompanied by MT2A upregulation and NF-κB inactivation. Histopathologic analysis of GC specimens from patients showed a significant increase in MT2A expression following DOC treatment. GC patients with high MT2A expression in tumor specimens showed significantly improved response to chemotherapy and prolonged survival compared with those with low MT2A expression in tumors.

INNOVATION AND CONCLUSION

We conclude that DATS exerts its anti-GC activity and enhances chemosensitivity of GC to DOC by epigenetic upregulation of MT2A to attenuate NF-κB signaling. Our findings delineate a mechanistic basis of MT2A/NF-κB signaling for DATS- and DOC-mediated anti-GC effects, suggesting that MT2A may be a chemosensitivity indicator in GC patients receiving DOC-based treatment and a promising target for more effective treatment of GC by combination of DATS and DOC. Antioxid. Redox Signal. 24, 839-854.

Downregulation of importin-9 protects MCF-7 cells against apoptosis induced by the combination of garlic-derived alliin and paclitaxel

Numerous studies on the biological mechanism of breast cancer have identified a number of potential therapeutic molecular targets. In this context, one type of potential candidates appears to be agents that target the actin cytoskeleton of cancer cells or regulate actin cytoskeleton dynamics. The aim of the present study was to study the impact of altered actin transport between the cytoplasm and nucleus by the downregulation of importin-9 (IPO9) in breast adenocarcinoma MCF-7 cells exposed to an apoptosis-inducing combination of garlic-derived S-allyl-L-cysteine sulfoxide (alliin) and paclitaxel (PTX). The expression of IPO9 was downregulated by the transfection of non-aggressive breast cancer MCF-7 cells with siRNA against IPO9. The altered expression of IPO9 and cofilin-1 (CFL1) was examined using western blotting. Moreover, the effect of the downregulation of IPO9 on cell death induced by the combination of PTX and alliin was also investigated. The alterations of IPO9 and CFL1 levels were also related with F-actin organizational changes and F-actin fluorescence intensity in the nuclear/perinuclear area of the cells. The results presented here indicate that alliin and PTX act synergistically to promote and potentiate apoptosis in MCF-7 cells. Furthermore, using RNA interference technique, we showed that downregulation of IPO9 expression was correlated with a significant reduction in the apoptotic cell population as well as with a decrease in F-actin content in whole cells, and in the cortical and nuclear/perinuclear areas of the cells. Simultaneously, the downregulation of IPO9 was also accompanied by the increased post-translational expression of CFL1. Furthermore, the data obtained in the present study allow us to conclude that CFL1 itself does not translocate actin into the cell nucleus but this transport requires the functional expression of IPO9.

Investigation of estrogen receptor (ESR1) for breast cancer from traditional Chinese medicine

Recently, an important topic of breast cancer had been published in 2013. In this report, estrogen receptor (ESR1) had defined the relation of hormone-cause breast cancer. The screening of traditional Chinese medicine (TCM) database has found the molecular compounds by simulating molecular docking and molecular dynamics to regulate ESR1. S-Allylmercaptocysteine and 5-hydroxy-L-tryptophan are selected according to the highest docking score than that of other TCM compounds and Raloxifene (control). The simulation from molecular dynamics is helpful in analyzing and detecting the protein-ligand interactions. After a comparing the control and the Apo form, then based on the docking poses, hydrophobic interactions, hydrogen bond and structure variations, this research postulates that S-allylmercaptocysteine may be more appropriate than other compounds for protein-ligand interaction.

Novel 3,5-bis(arylidene)-4-oxo-1-piperidinyl dimers: structure-activity relationships and potent antileukemic and antilymphoma cytotoxicity

Novel clusters of 3,5-bis(benzylidene)-4-oxo-1-piperidinyl dimers 3-5 were evaluated against human Molt4/C8 and CEM T-lymphocytes and human HeLa cervix adenocarcinoma cells as well as murine L1210 leukemia neoplasms. Several of these compounds demonstrated IC50 values in the submicromolar and low micromolar range and compounds possessing 4-fluoro, 4-chloro and 3,4,5-trimethoxy substituents in the series 3 and 4 were identified as potent molecules. A heat map revealed the very high cytotoxic potencies of representative compounds against a number of additional leukemic and lymphoma cell lines and displayed greater toxicity to these cells than nonmalignant MCF10A and Hs-27 neoplasms. These dienones are more refractory to breast and prostate cancers. The evaluation of representative compounds in series 3-5 against a panel of human cancer cell lines revealed them to be potent cytotoxins with average IC50 values ranging from 0.05 to 8.51 μM. In particular, the most potent compound 4g demonstrated over 382-fold and 590-fold greater average cytotoxic potencies in this screen than the reference drugs, melphalan and 5-fluorouracil, respectively. A mode of action investigation of two representative compounds 3f and 4f indicated that they induce apoptosis which is due, at least in part, to the activation of caspase-3 and depolarization of the mitochondrial membrane potential.

Garlic in health and disease

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

Phenethyl isothiocyanate sensitizes androgen-independent human prostate cancer cells to docetaxel-induced apoptosis in vitro and in vivo

PURPOSE

The present study was undertaken to determine efficacy of phenethyl isothiocyanate (PEITC) for sensitization of androgen-independent human prostate cancer cells (AIPC) to Docetaxel-induced apoptosis using cellular and xenograft models.

METHODS

Cell viability was determined by trypan blue dye exclusion assay. Microscopy and DNA fragmentation assay were performed to quantify apoptotic cell death in cultured cells. Protein levels were determined by immunoblotting. PC-3 prostate cancer xenograft model was utilized to determine in vivo efficacy of the PEITC and/or Docetaxel treatments.

RESULTS

Pharmacologic concentrations of PEITC augmented Docetaxel-induced apoptosis in PC-3 and DU145 cells in association with suppression of Bcl-2 and XIAP protein levels and induction of Bax and Bak. The PEITC-Docetaxel combination was markedly more efficacious against PC-3 xenograft in vivo compared with PEITC or Docetaxel alone. Significantly higher counts of apoptotic bodies were also observed in tumor sections from mice treated with the PEITC-Docetaxel combination compared with PEITC or Docetaxel alone. The PEITC and/or Docetaxel-mediated changes in the levels of apoptosis regulating proteins in the tumor were generally consistent with the molecular alterations observed in cultured cells.

CONCLUSION

These results offer obligatory impetus to test PEITC-Docetaxel combination for the treatment of AIPC in a clinical setting.

Anti-Inflammatory Agents for Cancer Therapy

Inflammation is closely linked to cancer, and many anti-cancer agents are also used to treat inflammatory diseases, such as rheumatoid arthritis. Moreover, chronic inflammation increases the risk for various cancers, indicating that eliminating inflammation may represent a valid strategy for cancer prevention and therapy. This article explores the relationship between inflammation and cancer with an emphasis on epidemiological evidence, summarizes the current use of anti-inflammatory agents for cancer prevention and therapy, and describes the mechanisms underlying the anti-cancer effects of anti-inflammatory agents. Since monotherapy is generally insufficient for treating cancer, the combined use of anti-inflammatory agents and conventional cancer therapy is also a focal point in discussion. In addition, we also briefly describe future directions that should be explored for anti-cancer anti-inflammatory agents.

[Histological modifications observed in prostate after preserving treatments for prostate cancer and their impact on Gleason score interpretation]

Total prostatectomy remains the main treatment for intermediate risk prostate cancer with a life expectancy greater than 10 years. In other cases non-surgical treatments can be proposed: external radiotherapy (exclusive or combined anti-androgen therapy), brachytherapy with permanent implants, high frequency ultrasounds (HIFU, Ablatherm), cryotherapy or exclusive hormonal treatment. For such patients in case of biological recurrence, prostate biopsies are usually performed in order to affirm the local recurrence. The histological confirmation of persistent tumor is usually required before any treatment: salvage surgery, cryotherapy, and brachytherapy or high intensity focused ultrasound (HIFU). Pathologists must be aware of the histological modifications induced by these different treatments in order to ensure an optimal interpretation of the biopsies. In this review, we describe the modifications observed in the normal prostate and in cancers after these various therapeutic methods, and also after alpha reductase inhibitors proposed as treatment of benign prostate hypertrophy and prostate cancer chemoprevention.