Guggulsterone sensitized drug-resistant human hepatocarcinoma cells to doxorubicin through a Cox-2/P-gp dependent pathway

In vitro models to evaluate multidrug resistance in cancer cells: Biochemical and morphological techniques and pharmacological strategies

The overexpression of ATP-binding cassette (ABC) transporters contributes to the failure of chemotherapies and symbolizes a great challenge in oncology, associated with the adaptation of tumor cells to anticancer drugs such that these transporters become less effective, a mechanism known as multidrug resistance (MDR). The aim of this review is to present the most widely used methodologies for induction and comprehension of in vitro models for detection of multidrug-resistant (MDR) modulators or inhibitors, including biochemical and morphological techniques for chemosensitivity studies. The overexpression of MDR proteins, predominantly, the subfamily glycoprotein-1 (P-gp or ABCB1) multidrug resistance, multidrug resistance-associated protein 1 (MRP1 or ABCCC1), multidrug resistance-associated protein 2 (MRP2 or ABCC2) and cancer resistance protein (ABCG2), in chemotherapy-exposed cancer lines have been established/investigated by several techniques. Amongst these techniques, the most used are (i) colorimetric/fluorescent indirect bioassays, (ii) rhodamine and efflux analysis, (iii) release of 3,30-diethyloxacarbocyanine iodide by fluorescence microscopy and flow cytometry to measure P-gp function and other ABC transporters, (iv) exclusion of calcein-acetoxymethylester, (v) ATPase assays to distinguish types of interaction with ABC transporters, (vi) morphology to detail phenotypic characteristics in transformed cells, (vii) molecular testing of resistance-related proteins (RT-qPCR) and (viii) 2D and 3D models, (ix) organoids, and (x) microfluidic technology. Then, in vitro models for detecting chemotherapy MDR cells to assess innovative therapies to modulate or inhibit tumor cell growth and overcome clinical resistance. It is noteworthy that different therapies including anti-miRNAs, antibody-drug conjugates (to natural products), and epigenetic modifications were also considered as promising alternatives, since currently no anti-MDR therapies are able to improve patient quality of life. Therefore, there is also urgency for new clinical markers of resistance to more reliably reflect in vivo effectiveness of novel antitumor drugs.

Current stage of preclinical and clinical development of guggulsterone in cancers: Challenges and promises

Throughout human history, the utilization of medicinal herbs has been recognized as a crucial defense against various ailments, including cancer. Natural products with potential anticancer properties, capable of inducing apoptosis in cancer cells, have garnered substantial attention. One such agent under investigation is guggulsterone (GS), a phytosterol derived from the gum resin of the Commiphora mukul tree. This review aims to provide a comprehensive summary of recent studies elucidating the anticancer molecular mechanisms and molecular targets of GS, guiding future research and potential applications as an adjuvant drug in cancer therapy. Recent in vivo and in vitro studies have explored the biological activities of the active ingredients in Commiphora mukul. Specifically, GS emerges as a potential cancer chemopreventive and therapeutic agent. The investigations delve into the impact of GS on constitutively activated survival pathways, including Janus kinase/signal transducer and activator of transcription (JAK/STAT), nuclear factor-kappa B (NF-kB), and PI3-kinase/AKT signaling pathways. These pathways regulate antiapoptotic and proinflammatory genes, exerting control over growth and inflammatory responses. The findings highlight the potential of GS in disrupting survival pathways crucial for cancer cell viability. The inhibition of JAK/STAT, NF-kB, and PI3-kinase/AKT signaling pathways positions GS as a promising candidate for cancer therapy. The review synthesizes evidence from diverse studies, underscoring the multifaceted biological activities of GS in cancer prevention and treatment. To advance our understanding, future clinical and translational studies are imperative to determine effective doses in humans. Additionally, there is a need for the development of new pharmaceutical forms of GS to optimize therapeutic effects. This comprehensive review provides a foundation for ongoing research, offering insights into the potential of GS as a valuable addition to the armamentarium against cancer.

Guggulsterone from Commiphora mukul potentiates anti-glioblastoma efficacy of temozolomide in vitro and in vivo via down-regulating EGFR/PI3K/Akt signaling and NF-κB activation

ETHNOPHARMACOLOGICAL RELEVANCE

Myrrh is an aromatic oleo-gum resin extracted from the stem of Commiphora myrrha (Nees) Engl., and has the efficacies to promote blood circulation and remove blood stasis. Myrrh is mainly used for the treatment of chronic diseases including cancer. Guggulsterone, a major active steroid extracted from myrrh, has been found to inhibit cancer cell growth. Glioblastoma is the most common malignancy of central nervous system, and its prognosis remains very poor mainly due to chemotherapeutic resistance. The active status of EGFR/PI3K/Akt and NF-κB signaling in glioblastoma contributed to poor response for chemotherapy, and blocking this signaling with antagonists sensitized glioblastoma cells to chemotherapy.

AIM OF THE STUDY

The present study will investigate whether guggulsterone potentiates the anti-glioblastoma efficacy of temozolomide by down-regulating EGFR/PI3K/Akt signaling and NF-κB activation.

MATERIALS AND METHODS

Cell viability and proliferation was determined by cell counting Kit-8 and colony formation assays. Cell apoptosis was evaluated by Annexin V/PI and hoechst 33342 staining assays. Molecular techniques such as western blotting and real-time quantitative PCR were used to demonstrate guggulsterone in vitro effect on EGFR/PI3K/Akt signaling and NF-κB activation. Finally, in vivo studies were performed in orthotopic mouse models of glioblastoma.

RESULTS

The results demonstrated that guggulsterone enhanced temozolomide-induced growth inhibition and apoptosis in human glioblastoma U251 and U87 cells. Furthermore, the synergistic anti-glioblastoma efficacy between guggulsterone and temozolomide was intimately associated with the inhibition of EGFR/PI3K/Akt signaling and NF-κB activation in U251 and U87 cells. Our in vivo results on orthotopic xenograft models similarly indicated that guggulsterone potentiated temozolomide-induced tumor growth inhibition through suppressing EGFR/PI3K/Akt signaling pathway and NF-кB activity.

CONCLUSIONS

The present study suggested that guggulsterone potentiated anti-glioblastoma efficacy of temozolomide through down-regulating EGFR/PI3K/Akt signaling pathway and NF-кB activation.

Anti-cancer activity of guggulsterone by modulating apoptotic markers: a systematic review and meta-analysis

Background: Guggulsterone (pregna-4,17-diene-3,16-dione; C₂₁H₂₈O₂) is an effective phytosterol isolated from the gum resin of the tree Commiphora wightii (Family Burseraceae) and is responsible for many of the properties of guggul. This plant is widely used as traditional medicine in Ayurveda and Unani system of medicine. It exhibits several pharmacological activities, such as anti-inflammatory, analgesic, antibacterial, anti-septic and anticancer. In this article, the activities of Guggulsterone against cancerous cells were determined and summarized. Methods: Using 7 databases (PubMed, PMC, Google Scholar, Science Direct, Scopus, Cochrane and Ctri.gov), the literature search was conducted since conception until June 2021. Extensive literature search yielded 55,280 studies from all the databases. A total of 40 articles were included in the systematic review and of them, 23 articles were included in the meta-analysis.The cancerous cell lines used in the studies were for pancreatic cancer, hepatocellular carcinoma, head and neck squamous cell carcinoma, cholangiocarcinoma, oesophageal adenocarcinoma, prostrate cancer, colon cancer, breast cancer, gut derived adenocarcinoma, gastric cancer, colorectal cancer, bladder cancer, glioblastoma, histiocytic leukemia, acute myeloid leukemia and non-small cell lung cancer. The reliability of the selected studies was assessed using ToxRTool. Results: Based on this review, guggulsterone significantly affected pancreatic cancer (MiaPaCa-2, Panc-1, PC-Sw, CD18/HPAF, Capan1, PC-3), hepatocellular carcinoma (Hep3B, HepG2, PLC/PRF/5R), head and neck squamous cell carcinoma (SCC4, UM-22b, 1483), cholangiocarcinoma (HuCC-T1, RBE, Sk-ChA-1, Mz-ChA-1) and oesophageal adenocarcinoma (CP-18821, OE19), prostrate cancer (PC-3), colon cancer (HT-29), breast cancer (MCF7/DOX), gut derived adenocarcinoma (Bic-1), gastric cancer (SGC-7901), colorectal cancer (HCT116), bladder cancer (T24, TSGH8301), glioblastoma (A172, U87MG, T98G), histiocytic leukemia (U937), acute myeloid leukemia (HL60, U937) and non-small cell lung cancer (A549, H1975) by inducing apoptotic pathways, inhibiting cell proliferation, and regulating the expression of genes involved in apoptosis. Guggulsterone is known to have therapeutic and preventive effects on various categories of cancers. It can inhibit the progression of tumors and can even reduce their size by inducing apoptosis, exerting anti-angiogenic effects, and modulating various signaling cascades. In vitro studies reveal that Guggulsterone inhibits and suppresses the proliferation of an extensive range of cancer cells by decreasing intrinsic mitochondrial apoptosis, regulating NF-kB/STAT3/β-Catenin/PI3K/Akt/CHOP pathway, modulating the expression of associated genes/proteins, and inhibiting angiogenesis. Furthermore, Guggulsterone reduces the production of inflammatory markers, such as CDX2 and COX-2. The other mechanism of the Guggulsterone activity is the reversal of P-glycoprotein-mediated multidrug resistance. Twenty three studies were selected for meta-analysis following the PRISMA statements. Fixed effect model was used for reporting the odds ratio. The primary endpoint was percentage apoptosis. 11 of 23 studies reported the apoptotic effect at t = 24 h and pooled odds ratio was 3.984 (CI 3.263 to 4.865, p < 0.001). 12 studies used Guggulsterone for t > 24 h and the odds ratio was 11.171 (CI 9.148 to 13.643, 95% CI, p < 0.001). The sub-group analysis based on cancer type, Guggulsterone dose, and treatment effects. Significant alterations in the level of apoptotic markers were reported by Guggulsterone treatment. Conclusion: This study suggested that Guggulsterone has apoptotic effects against various cancer types. Further investigation of its pharmacological activity and mechanism of action should be conducted. In vivo experiments and clinical trials are required to confirm the anticancer activity.

Galectin-1 confers resistance to doxorubicin in hepatocellular carcinoma cells through modulation of P-glycoprotein expression

Galectin-1 (GAL1), a β-galactoside-binding protein abundantly expressed in the tumor microenvironment, has emerged as a key mechanism of chemoresistance developed by different tumors. Although increased expression of GAL1 is a hallmark of hepatocellular carcinoma (HCC) progression, aggressiveness and metastasis, limited information is available on the role of this endogenous lectin in HCC resistance to chemotherapy. Moreover, the precise mechanisms underlying this effect are uncertain. HCC has evolved different mechanisms of resistance to chemotherapy including those involving the P-glycoprotein (P-gp), an ATP-dependent drug efflux pump, which controls intracellular drug concentration. Here, we investigated the molecular mechanism underlying GAL1-mediated chemoresistance in HCC cells, particularly the involvement of P-gp in this effect. Our results show that GAL1 protected HepG2 cells from doxorubicin (DOX)- and sorafenib-induced cell death in vitro. Accordingly, GAL1-overexpressing HepG2 cells generated DOX-resistant tumors in vivo. High expression of GAL1 in HepG2 cells reduced intracellular accumulation of DOX likely by increasing P-gp protein expression rather than altering its membrane localization. GAL1-mediated increase of P-gp expression involved activation of the phosphatidylinositol-3 kinase (PI3K) signaling pathway. Moreover, 'loss-of-function' experiments revealed that P-gp mediates GAL1-driven resistance to DOX, but not to sorafenib, in HepG2 cells. Conversely, in PLC/PRF/5 cells, P-gp protein expression was undetectable and GAL1 did not control resistance to DOX or sorafenib, supporting the critical role of P-gp in mediating GAL1 effects. Collectively, our findings suggest that GAL1 confers chemoresistance in HCC through mechanisms involving modulation of P-gp, thus emphasizing the role of this lectin as a potential therapeutic target in HCC.

Advances in understanding the role of P-gp in doxorubicin resistance: Molecular pathways, therapeutic strategies, and prospects

P-glycoprotein (P-gp) is a drug efflux transporter that triggers doxorubicin (DOX) resistance. In this review, we highlight the molecular avenues regulating P-gp, such as Nrf2, HIF-1α, miRNAs, and long noncoding (lnc)RNAs, to reveal their participation in DOX resistance. These antitumor compounds and genetic tools synergistically reduce P-gp expression. Furthermore, ATP depletion impairs P-gp activity to enhance the antitumor activity of DOX. Nanoarchitectures, including liposomes, micelles, polymeric nanoparticles (NPs), and solid lipid nanocarriers, have been developed for the co-delivery of DOX with anticancer compounds and genes enhancing DOX cytotoxicity. Surface modification of nanocarriers, for instance with hyaluronic acid (HA), can promote selectivity toward cancer cells. We discuss these aspects with a focus on P-gp expression and activity.

Potential of guggulsterone, a farnesoid X receptor antagonist, in the prevention and treatment of cancer

Cancer is one of the most dreadful diseases in the world with a mortality of 9.6 million annually. Despite the advances in diagnosis and treatment during the last couple of decades, it still remains a serious concern due to the limitations associated with currently available cancer management strategies. Therefore, alternative strategies are highly required to overcome these glitches. The importance of medicinal plants as primary healthcare has been well-known from time immemorial against various human diseases, including cancer. Commiphora wightii that belongs to Burseraceae family is one such plant which has been used to cure various ailments in traditional systems of medicine. This plant has diverse pharmacological properties such as antioxidant, antibacterial, antimutagenic, and antitumor which mostly owes to the presence of its active compound guggulsterone (GS) that exists in the form of Z- and E-isomers. Mounting evidence suggests that this compound has promising anticancer activities and was shown to suppress several cancer signaling pathways such as NF-κB/ERK/MAPK/AKT/STAT and modulate the expression of numerous signaling molecules such as the farnesoid X receptor, cyclin D1, survivin, caspases, HIF-1α, MMP-9, EMT proteins, tumor suppressor proteins, angiogenic proteins, and apoptotic proteins. The current review is an attempt to summarize the biological activities and diverse anticancer activities (both in vitro and in vivo) of the compound GS and its derivatives, along with its associated mechanism against various cancers.

Emodin Reverses Gemcitabine Resistance of Pancreatic Cancer Cell Lines Through Inhibition of IKKβ/NF-κB Signaling Pathway

Background

Pancreatic cancer is one of the most malignant tumors, and gemcitabine has been considered as the standard treatment and been widely utilized as a first-line drug for advanced pancreatic cancer, but gemcitabine-resistance always occurs after a short period of treatment.

Methods

Two pancreatic cancer cell lines Panc-1 and MIA-PaCa-2 were used as the study subject and their gemcitabine-resistant cells were established. Both drug-resistant cells were divided into four groups: blank, emodin, gemcitabine, and emodin+gemcitabine. Cell viability was detected by MTT assay. Flow cytometry was performed to detect cell apoptosis rate and P-gp function. Quantitative real-time polymerase chain reaction and Western blotting were used to detect Survivin, XIAP, Caspase-9/3, NF-κB p65, IKKβ and IκB-α mRNA/protein expressions, respectively. Electrophoretic mobility shift assay (EMSA) was performed to detect NF-κB binding activity. Rhodamine 123 efflux assay was used to detect P-gp function.

Results

Emodin could inhibit cell activity in all cell lines. Both emodin and gemcitabine can significantly increase the apoptosis rate, and the combination of the two drugs can further significantly increase the apoptosis rate in normal pancreatic cancer cell lines. In both drug-resistant pancreatic cancer cell lines, it can be observed that although gemcitabine can increase the apoptosis rate, the effect of promoting apoptosis is significantly lower than that of emodin; the drug combination can still significantly increase the apoptosis rate on the basis of emodin alone. Emodin can significantly reduce the mRNA and protein expression levels of Survivin, XIAP, NF-κB, and IKKβ, and significantly increase the mRNA and protein expression levels of Caspase-3/9 and IκB-α. Emodin significantly reduced NF-κB activity and emodin significantly promoted P-gp fluorescence intensity from Rhodamine 123 efflux assay.

Conclusion

Emodin inhibits the expression of IKKβ, thereby inhibiting the expression and activity of downstream NF-κB, and inhibits P-gp function at the same time, ultimately achieving the purpose of reversing the drug-resistance of pancreatic cancer cell lines.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

Googling the Guggul (Commiphora and Boswellia) for Prevention of Chronic Diseases

Extensive research during last 2 decades has revealed that most drugs discovered today, although costs billions of dollars for discovery, and yet they are highly ineffective in their clinical response. For instance, the European Medicines Agency has approved 68 anti-cancer drugs, and out of which 39 has reached the market level with no indication of increased survival nor betterment of quality of life. Even when drugs did improve survival rate compared to available treatment strategies, most of these were found to be clinically insignificant. This is a fundamental problem with modern drug discovery which is based on thinking that most chronic diseases are caused by alteration of a single gene and thus most therapies are single gene-targeted therapies. However, extensive research has revealed that most chronic diseases are caused by multiple gene products. Although most drugs designed by man are mono-targeted therapies, however, those designed by "mother nature" and have been used for thousands of years, are "multi-targeted" therapies. In this review, we examine two agents that have been around for thousands of years, namely "guggul" from Commiphora and Boswellia. Although we are all familiar with the search engine "google," this is another type of "guggul" that has been used for centuries and being explored for its various biological activities. The current review summarizes the traditional uses, chemistry, in vitro and in vivo biological activities, molecular targets, and clinical trials performed with these agents.

Molecular bases of the poor response of liver cancer to chemotherapy

A characteristic shared by most frequent types of primary liver cancer, i.e., hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) in adults, and in a lesser extent hepatoblastoma (HB) mainly in children, is their high refractoriness to chemotherapy. This is the result of synergic interactions among complex and diverse mechanisms of chemoresistance (MOC) in which more than 100 genes are involved. Pharmacological treatment, although it can be initially effective, frequently stimulates the expression of MOC genes, which results in the relapse of the tumor, usually with a more aggressive and less chemosensitive phenotype. Identification of the MOC genetic signature accounting for the "resistome" present at each moment of tumor life would prevent the administration of chemotherapeutic regimens without chance of success but still with noxious side effects for the patient. Moreover, a better description of cancer cells strength is required to develop novel strategies based on pharmacological, cellular or gene therapy to overcome liver cancer chemoresistance.

In silico comparisons between natural inhibitors of ABCB1/P-glycoprotein to overcome doxorubicin-resistance in the NCI/ADR-RES cell line

To investigate compound-protein binding mode and molecular dynamic simulation of P-glycoprotein (P-gp), in silico studies were performed to compare 12 naturally occurring compounds using two softwares. The net results showed that piperine (PIP) had the best binding affinity. In vitro studies on doxorubicin (DOX)-resistant NCI/ADR-RES cells, known to express P-gp, showed that, dose-dependently, PIP significantly increased intracellular accumulation of rhodamine-123 and had cytotoxic effects accessed by MTT assay. In addition, PIP at 25 and 50μM significantly potentiated DOX-induced cytotoxicity on the same cell line. P-gp ATPase assay showed that both DOX and PIP had dose-dependent inhibition of orthovandate-sensitive ATPase activity, indicating they are both P-gp inhibitors, with IC₅₀ of 84±1 and 37±2μM, respectively. PIP did not show any activation of ATPase activity, while DOX did, indicating that P-gp does not accept PIP as a substrate. Using DOX at concentration 33.33μM together with PIP (100μM), DOX-mediated P-gp ATPase activity was decreased to levels 4-folds lower than DOX alone. In conclusion, both in silico and in vitro studies confirm that PIP is an inhibitor of P-gp mediated DOX efflux, suggesting PIP as a promising adjuvant to DOX cancer chemotherapy.

Evaluation of guggulsterone derivatives as novel kidney cell protective agents against cisplatin-induced nephrotoxicity

Guggulsterone derivatives were prepared using [3+2] click chemistry with aryl and alkyl acetylene. The series of derivatives were evaluated for their cellular protective effects on cisplatin-treated cultured LLC-PK1 kidney epithelial cells. Among the guggulsterone-triazole derivatives, compound 6g, which contains a hydroxyl methyl group, was the most active of all the derivatives. In an additional study, we determined that inhibition of the mitogen-activated protein kinase/caspase-3 signaling cascade by 6g mediates its protective effects against cytotoxicity in cultured LLC-PK1 cells.