The potential role of curcumin in prostate cancer: the importance of optimizing pharmacokinetics in clinical studies

The Role of Curcumin in Prostate Cancer Cells and Derived Spheroids

A major challenge in the clinical management of prostate cancer (PC) is to inhibit tumor growth and prevent metastatic spreading. In recent years, considerable efforts have been made to discover new compounds useful for PC therapy, and promising advances in this field were reached. Drugs currently used in PC therapy frequently induce resistance and PC progresses toward metastatic castration-resistant forms (mCRPC), making it virtually incurable. Curcumin, a commercially available nutritional supplement, represents an attractive therapeutic agent for mCRPC patients. In the present study, we compared the effects of chemotherapeutic drugs such as docetaxel, paclitaxel, and cisplatin, to curcumin, on two PC cell lines displaying a different metastatic potential: DU145 (moderate metastatic potential) and PC-3 (high metastatic potential). Our results revealed a dose-dependent reduction of DU145 and PC-3 cell viability upon treatment with curcumin similar to chemotherapeutic agents (paclitaxel, cisplatin, and docetaxel). Furthermore, we explored the EGFR-mediated signaling effects on ERK activation in DU145 and PC-3 cells. Our results showed that DU145 and PC-3 cells overexpress EGFR, and the treatment with chemotherapeutic agents or curcumin reduced EGFR expression levels and ERK activation. Finally, chemotherapeutic agents and curcumin reduced the size of DU145 and PC-3 spheroids and have the potential to induce apoptosis and also in Matrigel. In conclusion, despite different studies being carried out to identify the potential synergistic curcumin combinations with chemopreventive/therapeutic efficacy for inhibiting PC growth, the results show the ability of curcumin used alone, or in combinatorial approaches, to impair the size and the viability of PC-derived spheroids.

Prostate cancer: Therapeutic prospect with herbal medicine

Prostate cancer (PCa) is a major cause of morbidity and mortality in men worldwide. A geographic variation on the burden of the disease suggested that the environment, genetic makeup, lifestyle, and food habits modulate one's susceptibility to the disease. Although it has been generally thought to be an older age disease, and awareness and timely execution of screening programs have managed to contain the disease in the older population over the last decades, the incidence is still increasing in the population younger than 50. Existing treatment is efficient for PCa that is localized and responsive to androgen. However, the androgen resistant and metastatic PCa are challenging to treat. Conventional radiation and chemotherapies are associated with severe side effects in addition to being exorbitantly expensive. Many isolated phytochemicals and extracts of plants used in traditional medicine are known for their safety and diverse healing properties, including many with varying levels of anti-PCa activities. Many of the phytochemicals discussed here, as shown by many laboratories, inhibit tumor cell growth and proliferation by interfering with the components in the pathways responsible for the enhanced proliferation, metabolism, angiogenesis, invasion, and metastasis in the prostate cells while upregulating the mechanisms of cell death and cell cycle arrest. Notably, many of these agents simultaneously target multiple cellular pathways. We analyzed the available literature and provided an update on this issue in this review article.

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Prostate cancer in a major cause of death in older population worldwide.

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Efficacies of current treatment options are limited in many cases.

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Phytochemicals and extracts isolated from plants show anti-prostate cancer activity with unique mechanisms.

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Certain phytochemicals alone or in combination with current chemotherapy show therapeutic promise.

Natural Product-Based Studies for the Management of Castration-Resistant Prostate Cancer: Computational to Clinical Studies

Background: With prostate cancer being the fifth-greatest cause of cancer mortality in 2020, there is a dire need to expand the available treatment options. Castration-resistant prostate cancer (CRPC) progresses despite androgen depletion therapy. The mechanisms of resistance are yet to be fully discovered. However, it is hypothesized that androgens depletion enables androgen-independent cells to proliferate and recolonize the tumor. Objectives: Natural bioactive compounds from edible plants and herbal remedies might potentially address this need. This review compiles the available cheminformatics-based studies and the translational studies regarding the use of natural products to manage CRPC. Methods: PubMed and Google Scholar searches for preclinical studies were performed, while ClinicalTrials.gov and PubMed were searched for clinical updates. Studies that were not in English and not available as full text were excluded. The period of literature covered was from 1985 to the present. Results and Conclusion: Our analysis suggested that natural compounds exert beneficial effects due to their broad-spectrum molecular disease-associated targets. In vitro and in vivo studies revealed several bioactive compounds, including rutaecarpine, berberine, curcumin, other flavonoids, pentacyclic triterpenoids, and steroid-based phytochemicals. Molecular modeling tools, including machine and deep learning, have made the analysis more comprehensive. Preclinical and clinical studies on resveratrol, soy isoflavone, lycopene, quercetin, and gossypol have further validated the translational potential of the natural products in the management of prostate cancer.

Potential Therapeutic Targets of Curcumin, Most Abundant Active Compound of Turmeric Spice: Role in the Management of Various Types of Cancer

BACKGROUND

Curcumin, an active compound of turmeric spice, is one of the most-studied natural compounds and has been widely recognized as a chemopreventive agent. Several molecular mechanisms have proven that curcumin and its analogs play a role in cancer prevention through modulating various cell signaling pathways as well as in the inhibition of the carcinogenesis process.

OBJECTIVE

To study the potential role of curcumin in the management of various types of cancer through modulating cell signalling molecules based on available literature and recent patents.

METHODS

A wide-ranging literature survey was performed based on Scopus, PubMed, PubMed Central, and Google scholar for the implication of curcumin in cancer management, along with a special emphasis on human clinical trials. Moreover, patents were searched through www.google.com/patents, www.freepatentsonline.com, and www.freshpatents.com.

RESULT

Recent studies based on cancer cells have proven that curcumin has potential effects against cancer cells as it prevents the growth of cancer and acts as a cancer therapeutic agent. Besides, curcumin exerted anti-cancer effects by inducing apoptosis, activating tumor suppressor genes, cell cycle arrest, inhibiting tumor angiogenesis, initiation, promotion, and progression stages of tumor. It was established that co-treatment of curcumin and anti-cancer drugs could induce apoptosis and also play a significant role in the suppression of the invasion and metastasis of cancer cells.

CONCLUSION

Accumulating evidences suggest that curcumin has the potential to inhibit cancer growth, induce apoptosis, and modulate various cell signaling pathway molecules. Well-designed clinical trials of curcumin based on human subjects are still needed to establish the bioavailability, mechanism of action, efficacy, and safe dose in the management of various cancers.

Pleiotropic nature of curcumin in targeting multiple apoptotic-mediated factors and related strategies to treat gastric cancer: A review

Gastric cancer (GC) is one of the major reasons for cancer-associated death and exhibits the second-highest mortality rate worldwide. Several advanced approaches have been designed to treat GC; however, these strategies possess many innate complications. In view of this, the upcoming research relying on natural products could result in designing potential anticancer agents with fewer side effects. Curcumin, isolated from the rhizomes of Curcuma longa L. has several medicinal properties like antiinflammatory, antioxidant, antiapoptotic, antitumor, and antimetastatic. Such pleiotropic nature of curcumin impedes the invasion and proliferation of GC by targeting several oncogenic factors like p23, human epidermal factor receptor2 including Helicobacter pylori. The side effect of chemotherapy, that is, chemotherapeutic resistance and radiotherapy could be reduced combination therapy of curcumin. Moreover, the photodynamic therapy of curcumin destroys the cancer cells without affecting normal cells. However, further more potential studies are required to establish the potent efficacy of curcumin in the treatment of GC. The current review details the anticancer activities of curcumin and related strategies which could be employed to treat GC with additional focus on its inhibitory properties against viability, proliferation, and migration of GC cells through cell cycle arrest and stimulation by apoptosis-mediated factors.

Chemotherapeutic efficacy of curcumin and resveratrol against cancer: Chemoprevention, chemoprotection, drug synergism and clinical pharmacokinetics

The frequent inefficiency of conventional cancer therapies due to drug resistance, non-targeted drug delivery, chemotherapy-associated toxic side effects turned the focus to bioactive phytochemicals. In this context, curcumin and resveratrol have emerged as potent chemopreventive and chemoprotective compounds modulating apoptotic and autophagic cell death pathways in cancer in vitro and in vivo. As synergistic agents in combination with clinically established anticancer drugs, the enhanced anticancer activity at reduced chemotherapy-associated toxicity towards normal organs can be explained by improved pharmacokinetics, pharmacodynamics, bioavailability and metabolism. With promising preclinical and clinical applications, the design of drug-loaded nanoparticles, nanocarriers, liposomes and micelles have gained much attention to improve target specificity and drug efficacy. The present review focuses on the molecular modes of chemoprevention, chemoprotection and drug synergism with special emphasis to preclinical and clinical applications, pharmacokinetics, pharmacodynamics and advanced drug delivery methods for the development of next-generation personalized cancer therapeutics.

Inflammation as a Driver of Prostate Cancer Metastasis and Therapeutic Resistance

Simple Summary

Prostate cancer is the most common malignancy in men, with a high mortality rate when disease progresses to metastasis and therapeutic resistance. Evidence implicates inflammation as a driver of prostate cancer risk and has a significant impact on processes in the tumor microenvironment that facilitate progression to advanced therapeutically resistant disease. In this review, we discuss the sources of inflammation in the prostate, the functional contribution of the critical inflammatory effectors to prostate cancer initiation and metastatic progression, and the therapeutic challenges that they impose on treatment of advanced disease and overcoming therapeutic resistance. Full understanding of the role of inflammation in prostate cancer progression to advanced metastatic disease and tumor relapse will aid in the development of personalized predictive biomarkers and therapy to reduce the burden and mortality in prostate cancer patients.

Abstract

Prostate cancer is the most common malignancy among men, and progression to metastasis and the emergence of therapeutically resistant disease confers a high mortality rate. Growing evidence implicates inflammation as a driver of prostate cancer development and progression, resulting in increased cancer risk for prostate cancer. Population-based studies revealed that the use of antinflammatory drugs led to a 23% risk reduction prostate cancer occurrence, a negative association that was stronger in men who specifically used COX-2 inhibitors. Furthermore, patients that were taking aspirin had a 21% reduction in prostate cancer risk, and further, long-term users of daily low dose aspirin had a 29% prostate cancer risk reduction as compared to the controls. Environmental exposure to bacterial and viral infections, exposure to mutagenic agents, and genetic variations predispose the prostate gland to inflammation, with a coordinated elevated expression of inflammatory cytokines (IL-6, TGF-β). It is the dynamics within the tumor microenvironment that empower these cytokines to promote survival and growth of the primary tumor and facilitate disease progression by navigating the immunoregulatory network, phenotypic epithelial-mesenchymal transition (EMT), angiogenesis, anoikis resistance, and metastasis. In this review, we discuss the sources of inflammation in the prostate, the functional contribution of the critical inflammatory effectors to prostate cancer initiation and metastatic progression, and the therapeutic challenges that they impose on treatment of advanced disease and overcoming therapeutic resistance. Growing mechanistic evidence supports the significance of inflammation in localized prostate cancer, and the systemic impact of the process within the tumor microenvironment on disease progression to advanced therapeutically-resistant prostate cancer. Rigorous exploitation of the role of inflammation in prostate cancer progression to metastasis and therapeutic resistance will empower the development of precise biomarker signatures and effective targeted therapeutics to reduce the clinical burden and lethal disease in the future.

Dietary Factors and Supplements Influencing Prostate Specific-Antigen (PSA) Concentrations in Men with Prostate Cancer and Increased Cancer Risk: An Evidence Analysis Review Based on Randomized Controlled Trials

The quest for dietary patterns and supplements efficient in down-regulating prostate-specific antigen (PSA) concentrations among men with prostate cancer (PCa) or increased PCa risk has been long. Several antioxidants, including lycopene, selenium, curcumin, coenzyme Q10, phytoestrogens (including isoflavones and flavonoids), green tea catechins, cernitin, vitamins (C, E, D) and multivitamins, medicinal mushrooms (Ganoderma lucidum), fruit extracts (saw palmetto, cranberries, pomegranate), walnuts and fatty acids, as well as combined supplementations of all, have been examined in randomized controlled trials (RCTs) in humans, on the primary, secondary, and tertiary PCa prevention level. Despite the plethora of trials and the variety of examined interventions, the evidence supporting the efficacy of most dietary factors appears inadequate to recommend their use.

Mechanism of Anti-Cancer Activity of Curcumin on Androgen-Dependent and Androgen-Independent Prostate Cancer

Prostate cancer (PCa) is a heterogeneous disease and ranked as the second leading cause of cancer-related deaths in males worldwide. The global burden of PCa keeps rising regardless of the emerging cutting-edge technologies for treatment and drug designation. There are a number of treatment options which are effectively treating localised and androgen-dependent PCa (ADPC) through hormonal and surgery treatments. However, over time, these cancerous cells progress to androgen-independent PCa (AIPC) which continuously grow despite hormone depletion. At this particular stage, androgen depletion therapy (ADT) is no longer effective as these cancerous cells are rendered hormone-insensitive and capable of growing in the absence of androgen. AIPC is a lethal type of disease which leads to poor prognosis and is a major contributor to PCa death rates. A natural product-derived compound, curcumin has been identified as a pleiotropic compound which capable of influencing and modulating a diverse range of molecular targets and signalling pathways in order to exhibit its medicinal properties. Due to such multi-targeted behaviour, its benefits are paramount in combating a wide range of diseases including inflammation and cancer disease. Curcumin exhibits anti-cancer properties by suppressing cancer cells growth and survival, inflammation, invasion, cell proliferation as well as possesses the ability to induce apoptosis in malignant cells. In this review, we investigate the mechanism of curcumin by modulating multiple signalling pathways such as androgen receptor (AR) signalling, activating protein-1 (AP-1), phosphatidylinositol 3-kinases/the serine/threonine kinase (PI3K/Akt/mTOR), wingless (Wnt)/ß-catenin signalling, and molecular targets including nuclear factor kappa-B (NF-κB), B-cell lymphoma 2 (Bcl-2) and cyclin D1 which are implicated in the development and progression of both types of PCa, ADPC and AIPC. In addition, the role of microRNAs and clinical trials on the anti-cancer effects of curcumin in PCa patients were also reviewed.

Therapies Targeted to Androgen Receptor Signaling Axis in Prostate Cancer: Progress, Challenges, and Hope

Prostate cancer is the mostly commonly diagnosed non-cutaneous malignancy and the second leading cause of cancer-related death affecting men in the United States. Moreover, it disproportionately affects the men of African origin, who exhibit significantly greater incidence and mortality as compared to the men of European origin. Since androgens play an important role in the growth of normal prostate and prostate tumors, targeting of androgen signaling has remained a mainstay for the treatment of aggressive prostate cancer. Over the years, multiple approaches have been evaluated to effectively target the androgen signaling pathway that include direct targeting of the androgens, androgen receptor (AR), AR co-regulators or other alternate mechanisms that impact the outcome of androgen signaling. Several of these approaches are currently in clinical practice, while some are still pending further development and clinical evaluation. This remarkable progress has resulted from extensive laboratory, pre-clinical and clinical efforts, and mechanistic learnings from the therapeutic success and failures. In this review, we describe the importance of androgen signaling in prostate cancer biology and advances made over the years to effectively target this signaling pathway. We also discuss emerging data on the resistance pathways associated with the failure of various androgen signaling- targeted therapies and potential of this knowledge for translation into future therapies for prostate cancer.

Curcumin and Its Derivatives as Potential Therapeutic Agents in Prostate, Colon and Breast Cancers

Cancer is a life-threatening disease and is the second leading cause of death around the world. The increasing threats of drug-resistant cancers indicate that there is an urgent need for the improvement or development of more effective anticancer agents. Curcumin, a phenolic compound originally derived from turmeric plant (Curcuma longa L. (Zingiberaceae family)) widely known as a spice and a coloring agent for food have been reported to possess notable anticancer activity by inhibiting the proliferation and metastasis, and enhancing cell cycle arrest or apoptosis in various cancer cells. In spite of all these benefits, the therapeutic application of curcumin in clinical medicine and its bioavailability are still limited due to its poor absorption and rapid metabolism. Structural modification of curcumin through the synthesis of curcumin-based derivatives is a potential approach to overcome the above limitations. Curcumin derivatives can overcome the disadvantages of curcumin while enhancing the overall efficacy and hindering drug resistance. This article reports a review of published curcumin derivatives and their enhanced anticancer activities.

Curcumin-Gene Expression Response in Hormone Dependent and Independent Metastatic Prostate Cancer Cells

The androgen receptor is one of the key targets for prostate cancer treatment. Despite its less satisfactory effects, chemotherapy is the most common treatment option for metastatic and/or castration-resistant patients. There are constant needs for novel anti-prostate cancer therapeutic/prevention agents. Curcumin, a known chemo-preventive agent, was shown to inhibit prostate cancer cell growth. This study aimed to unravel the inhibitory effect of curcumin in prostate cancer through analyzing the alterations of expressions of curcumin targeting genes clusters in androgen-dependent LNCaP cells and androgen-independent metastatic C4-2B cells. Hierarchical clustering showed the highest number of differentially expressed genes at 12 h post treatment in both cells, suggesting that the androgen-dependent/independent manner of curcumin impacts on prostate cancer cells. Evaluation of significantly regulated top canonical pathways highlighted that Transforming growth factor beta (TGF-β), Wingless-related integration site (Wnt), Phosphoinositide 3-kinase/Protein Kinase B/ mammalian target of rapamycin (PIK3/AKT(PKB)/mTOR), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) signaling were primarily inhibited, and Phosphatase and tensin homolog (PTEN) dependent cell cycle arrest and apoptosis pathways were elevated with curcumin treatment. The short term (3–24 h) and long term (48 h) effect of curcumin treatment revealed 31 and four genes modulated in both cell lines. TGF-β signaling, including the androgen/TGF-β inhibitor Prostate transmembrane protein androgen-induced 1 (PMEPA1), was the only pathway impacted by curcumin treatment after 48 h. Our findings also established that MYC Proto-Oncogene, basic helix-loop-helix (bHLH) Transcription Factor (MYC) signaling was down-regulated in curcumin-treated cell lines. This study established, for the first time, novel gene-networks and signaling pathways confirming the chemo-preventive and cancer-growth inhibitory nature of curcumin as a natural anti-prostate cancer compound.

Mild hyperthermia as a localized radiosensitizer for deep-seated tumors: investigation in an orthotopic prostate cancer model in mice

OBJECTIVE:

Non-ablative or mild hyperthermia (HT) has been shown in preclinical (and clinical) studies as a localized radiosensitizer that enhances the tumoricidal effects of radiation. Most preclinical in vivo HT studies use subcutaneous tumor models which do not adequately represent clinical conditions (e.g. proximity of normal/critical organs) or replicate the tumor microenvironment-both of which are important factors for eventual clinical translation. The purpose of this work is to demonstrate proof-of-concept of locoregional radiosensitization with superficially applied, radiofrequency (RF)-induced HT in an orthotopic mouse model of prostate cancer.

METHODS:

In a 4-arm study, 40 athymic male nude mice were inoculated in the prostate with luciferase-transfected human prostate cancer cells (PC3). Tumor volumes were allowed to reach 150-250 mm3 (as measured by ultrasound) following which, mice were randomized into (i) control (no intervention); (ii) HT alone; (iii) RT alone; and (iv) HT + RT. RF-induced HT was administered (Groups ii and iv) using the Oncotherm LAB EHY-100 device to achieve a target temperature of 41 °C in the prostate. RT was administered ~30 min following HT, using an image-guided small animal radiotherapy research platform. In each case, a dual arc plan was used to deliver 12 Gy to the target in a single fraction. One animal from each cohort was euthanized on Day 10 or 11 after treatment for caspase-9 and caspase-3 Western blot analysis.

RESULTS:

The inoculation success rate was 89%. Mean tumor size at randomization (~16 days post-inoculation) was ~189 mm3 . Following the administration of RT and HT, mean tumor doubling times in days were: control = 4.2; HT = 4.5; RT = 30.4; and HT + RT = 33.4. A significant difference (p = 0.036) was noted between normalized nadir volumes for the RT alone (0.76) and the HT + RT (0.40) groups. Increased caspase-3 expression was seen in the combination treatment group compared to the other treatment groups.

CONCLUSION:

These early results demonstrate the successful use of external mild HT as a localized radiosensitizer for deep-seated tumors.

ADVANCES IN KNOWLEDGE:

We successfully demonstrated the feasibility of administering external mild HT in an orthotopic tumor model and demonstrated preclinical proof-of-concept of HT-based localized radiosensitization in prostate cancer radiotherapy.

Randomized, double-blind, placebo-controlled phase II trial of nanocurcumin in prostate cancer patients undergoing radiotherapy

Clinical potential of curcumin in radiotherapy (RT) setting is outstanding and of high interest. The main purpose of this randomized controlled trial (RCT) was to assess the beneficial role of nanocurcumin to prevent and/or mitigate radiation-induced proctitis in prostate cancer patients undergoing RT. In this parallel-group study, 64 eligible patients with prostate cancer were randomized to receive either oral nanocurcumin (120 mg/day) or placebo 3 days before and during the RT course. Acute toxicities including proctitis and cystitis were assessed weekly during the treatment and once thereafter using CTCAE v.4.03 grading criteria. Baseline-adjusted hematologic nadirs were also analyzed and compared between the two groups. The patients undergoing definitive RT were followed to evaluate the tumor response. Nanocurcumin was well tolerated. Radiation-induced proctitis was noted in 18/31 (58.1%) of the placebo-treated patients versus 15/33 (45.5%) of nanocurcumin-treated patients (p = 0.313). No significant difference was also found between the two groups with regard to radiation-induced cystitis, duration of radiation toxicities, hematologic nadirs, and tumor response. In conclusion, this RCT was underpowered to indicate the efficacy of nanocurcumin in this clinical setting but could provide a considerable new translational insight to bridge the gap between the laboratory and clinical practice.