Centchroman inhibits proliferation of head and neck cancer cells through the modulation of PI3K/mTOR pathway

Evaluation of molecular effects associated with apoptosis, tumour progression, angiogenesis and metastasis by a novel combination of drugs with ormeloxifene in triple negative breast cancer cells

Aim

To investigate the molecular effects of a novel combination [sertraline and plumbagin (comb) with ormeloxifene (Orm)] for anticancer activity in triple negative breast cancer cell line "MDA-MB-231".

Methods

The cytotoxic effect of the drugs was analyzed by the MTT assay and nuclear morphological changes by acridine orange/ethidium bromide (AO/EB) staining. Induction of apoptosis by annexin V-FITC staining, active caspase-3 detection and cell cycle analysis were studied in vitro on "MDA-MB-231" cells. The qRT-PCR was done to explore the upregulation and down regulation of targeted genes for angiogenesis, metastasis, tumor suppression and protein folding on the triple negative breast cancer cells. The preliminary anti-angiogenic effect of the drugs was assessed by chorioallantoic membrane (CAM) assay.

Results

Orm showed inhibitory effects in "MDA-MB-231" cells in a dose and time dependent manner whereas; the drugs in combination gave better cytotoxic effects in the screening MTT assay. Orm + comb was more effective than Orm alone in eliciting apoptosis as well as inhibited the single cell to grow into a colony. CAM assay using Orm and Orm + comb suggested the anti-angiogenic potential which was further confirmed by the downregulation of VEGF in "MDA-MB-231" cells by qRT-PCR studies. The combination was found to effectively upregulate the expression of P53 and P21 and downregulate the gene expression of zinc finger E-box binding homeobox 1 (ZEB1) and heat shock protein 70 (HSP70) in "MDA-MB-231" cancer cells.

Conclusions

Collectively this study reveals the efficacy of Orm + comb as more significant than the clinically used tamoxifen (Tam). The study elucidates the promising novelty of the combination as a potential chemotherapeutic intervention for mitigating the aggressiveness of triple negative breast cancer and it addresses the intrinsic resistance caused by single drug treatments.

The Role of Estrogen and Estrogen Receptors in Head and Neck Tumors

Head and neck squamous cell carcinoma (HNSCC) is the most common histological form of head and neck tumors (HNTs), which originate from the epithelium of the lips and oral cavity, pharynx, larynx, salivary glands, nasal cavity, and sinuses. The main risk factors include consumption of tobacco in all forms and alcohol, as well as infections with high-risk human papillomaviruses or the Epstein-Barr virus. Regardless of the etiological agent, the risk of developing different types of HNTs is from two to more than six times higher in males than in females. The reason for such disparities probably lies in a combination of both biological and psychosocial factors. Therefore, it is hypothesized that exposure to female sex hormones, primarily estrogen, provides women with protection against the formation and metastasis of HNTs. In this review, we synthesized available knowledge on the role of estrogen and estrogen receptors (ERs) in the development and progression of HNTs, with special emphasis on membrane ERs, which are much less studied. We can summarize that in addition to epidemiologic studies unequivocally pointing to the protective effect of estrogen in women, an increased expression of both nuclear ERs, ERα, and ERβ, and membrane ERs, ERα36, GPER1, and NaV1.2, was present in different types of HNSCC, for which anti-estrogens could be used as an effective therapeutic approach.

Synthesis and Antitumor Activity of Brominated-Ormeloxifene (Br-ORM) against Cervical Cancer

Aberrant regulation of β-catenin signaling is strongly linked with cancer proliferation, invasion, migration, and metastasis, thus, small molecules that can inhibit this pathway might have great clinical significance. Our molecular modeling studies suggest that ormeloxifene (ORM), a triphenylethylene molecule that docks with β-catenin, and its brominated analogue (Br-ORM) bind more effectively with relatively less energy (-7.6 kcal/mol) to the active site of β-catenin as compared to parent ORM. Herein, we report the synthesis and characterization of a Br-ORM by NMR and FTIR, as well as its anticancer activity in cervical cancer models. Br-ORM treatment effectively inhibited tumorigenic features (cell proliferation and colony-forming ability, etc.) and induced apoptotic death, as evident by pronounced PARP cleavage. Furthermore, Br-ORM treatment caused cell cycle arrest at the G1-S phase. Mechanistic investigation revealed that Br-ORM targets the key proteins involved in promoting epithelial-mesenchymal transition (EMT), as demonstrated by upregulation of E-cadherin and repression of N-cadherin, Vimentin, Snail, MMP-2, and MMP-9 expression. Br-ORM also represses the expression and nuclear subcellular localization of β-catenin. Consequently, Br-ORM treatment effectively inhibited tumor growth in an orthotopic cervical cancer xenograft mouse model along with EMT associated changes as compared to vehicle control-treated mice. Altogether, experimental findings suggest that Br-ORM is a novel, promising β-catenin inhibitor and therefore can be harnessed as a potent anticancer small molecule for cervical cancer treatment.

Anticancer properties of arylchromenes and arylchromans: an overview

Cancers are a set of pathologies originated by cells that have the ability to divide and multiply uncontrollably, associated with the capacity to invade and colonize adjacent tissues. Chemotherapy is one of the main approaches of treatment for cancer patients. Despite of the numerous antineoplastic drugs available, cancer cannot be cured; particularly at the late stages deprived of any side effect. Arylchromenes and arylchromans are a group of small molecules, of natural or synthetic origin, of great interest as prototypes for the drug development, especially against cancer. In this chapter, we will present the antineoplastic activity studies of the most promising examples of these arylchromenes and arylchroman derivatives.

Comparative differential cytotoxicity of clinically used SERMs in human cancer lines of different origin and its predictive molecular docking studies of key target genes involved in cancer progression and treatment responses

SERMS like Tamoxifene, 5-hydroxy tamoxifene, raloxifene and endoxifene has been used for the treatment of hormonal imbalances and dependent cancers owing to their action via Estrogen receptors as in the treatment of estrogen sensitive breast cancers. Due to the adverse side effects, modifications and development of the existing or newer SERMS has always been of immense interest. Ormeloxifene, a SERM molecule manufactured by HLL Lifecare Ltd, India as birth control under the trade names Saheli, Novex, and Novex-DS which is also investigated against mastalgia, fibro-adenoma and abnormal uterine bleeding. Anti-cancer effects have been reported in estrogen dependent and independent cancers which shows its wide scope to be implemented in cancer therapy. Current investigation is a comprehensive effort to find the cytotoxic potential of Ormeloxifene in comparison with clinically used four SERMS in twenty six cancer cell lines of different origin using Adriamycin as positive control. Also the computational studies pertaining to selected target/ligand with respect to tumor progression, development, treatment responses and apoptosis. The studies proved effective cytotoxicity of Ormeloxifene on cancer cell lines with lower TGI, GI50 and LC50 values which are significantly comparable. Also the in silico studies proved that the docking score of the compound suggests the interaction of the compound which could tightly regulate key target genes controlling cancer like ER, EGFR kinase, EGFR-cSRC, HDAC-2, PARP-1 and BRAF. This study brings out the superior efficacy of Ormeloxifene compared to other SERMS with proven safety profile to be repositioned as an anti-cancer drug to treat diverse cancer types.

Centchroman prevents metastatic colonization of breast cancer cells and disrupts angiogenesis via inhibition of RAC1/PAK1/β-catenin signaling axis

AIMS

We have previously reported that Centchroman (CC), an oral contraceptive drug, inhibits breast cancer progression and metastasis. In this study, we investigated whether CC inhibits local invasion of tumor cells and/or their metastatic colonization with detailed underlying mechanisms.

MAIN METHODS

The effect of CC on the experimental metastasis and spontaneous metastasis was demonstrated by using tail-vein and orthotopic 4T1-syngeneic mouse tumor models, respectively. The anti-angiogenic potential of CC was evaluated using well established in vitro and in vivo models. The role of RAC1/PAK1/β-catenin signaling axis in the metastasis was investigated and validated using siRNA-mediated knockdown of PAK1 as well as by pharmacological PAK1-inhibitor.

KEY FINDINGS

The oral administration of CC significantly suppressed the formation of metastatic lung nodules in the 4T1-syngeneic orthotopic as well as experimental metastatic models. More importantly, CC treatment suppressed the tube formation and migration capacities of human umbilical vein endothelial cells (HUVEC) and inhibited pre-existing vasculature as well as the formation of neovasculature. The suppression of migration and invasion capacities of metastatic breast cancer cells upon CC treatment was associated with the inhibition of small GTPases (Rac1 and Cdc42) concomitant with the downregulation of PAK1 and downstream β-catenin signaling. In addition, CC upregulated the expression of miR-145, which is known to target PAK1.

SIGNIFICANCE

This study warrants the repurposing of CC as a potential therapeutic agent against metastatic breast cancer.

Pluronic Polymer-Based Ormeloxifene Nanoformulations Induce Superior Anticancer Effects in Pancreatic Cancer Cells

Utilization of safe cytotoxic agents with precise anticancer activity is considered as the prime focus of cancer therapeutics research. A greater incentive for such agents arises from the molecules/drugs that are already being used for other indications. Ormeloxifene (ORM) is a nonsteroidal, nonhormonal selective estrogen receptor modulator (SERM), which has been in human use for contraception purposes. Although in the recent past, many reports have suggested its emerging role as an anticancer agent, no significant attention was paid toward generating simple and safe nanoformulation(s) for improved therapeutic activity and tumor cell-specific delivery. Our aim is to develop nanoformulation(s) of ormeloxifene to improve its targeted delivery in tumor cells. We developed ormeloxifene nanoformulation(s) by utilizing various biocompatible polymers. The optimized formulations with pluronic polymers F127 and F68 show improved nanoparticle characteristics. These formulations show enhanced cellular uptake that allows ormeloxifene's intracellular availability. We further evaluated its improved anticancer activity by performing cell proliferation, flow cytometry, and immunoblotting assays. Overall, this study confirms possible novel nanoformulation(s) of ormeloxifene to be evolved as a new therapeutic modality for cancer treatment.

Drugs Repurposing in High-Grade Serous Ovarian Cancer

BACKGROUND

Ovary Carcinoma (OC) is the most lethal gynecological neoplasm due to the late diagnoses and to the common development of resistance to platinum-based chemotherapy. Thus, novel therapeutic approaches are urgently required. In this regard, the strategy of drug repurposing is becoming attractive. By this approach, the effectiveness of a drug originally developed for another indication is tested in a different pathology. The advantage is that data about pharmacokinetic properties and toxicity are already available. Thus, in principle, it is possible to reduce research costs and to speed up drug usage/marketing.

RESULTS

Here, some noticeable examples of repurposed drugs for OC, such as amiodarone, ruxolitinib, statins, disulfiram, ormeloxifenem, and Quinacrine, are reported. Amiodarone, an antiarrhythmic agent, has shown promising anti-OC activity, although the systemic toxicity should not be neglected. The JAK inhibitor, Ruxolitinib, may be employed particularly in coadministration with standard OC therapy as it synergistically interacts with platinum-based drugs. Particularly interesting is the use of statin which represent one of the most commonly administered drugs in aged population to treat hypercholesterolemia. Disulfiram, employed in the treatment of chronic alcoholism, has shown anti-OC properties. Ormeloxifene, commonly used for contraception, seems to be promising, especially due to the negligible side effects. Finally, Quinacrine used as an antimicrobial and anti-inflammatory drug, is able to downregulate OC cell growth and promote cell death.

CONCLUSION

Whereas further testing in patients are necessary to better clarify the therapeutic potential of repurposed drugs for OC, it is believed that their use, better if combined with OC targeted delivery systems, can significantly contribute to the development of novel and effective anti-OC treatments.

Genistein potentiates Centchroman induced antineoplasticity in breast cancer via PI3K/Akt deactivation and ROS dependent induction of apoptosis

AIMS

Recently, strategies of cancer treatment using combination of agents with distinct molecular mechanism(s) of action are considered more promising due to its high efficacy and reduced systemic toxicity. The study is aimed to improve the efficacy of selective estrogen receptor modulator, Centchroman (CC) by combination with the phytoestrogen Genistein (GN).

METHODS

Cytotoxicity was evaluated by Sulforhodamine B assay. Cell cycle analysis was done through flow cytometry. Further, Apoptosis was analyzed using Annexin V/PI staining, tunel assay and electron microscopic examination and verified using western blot analysis. In order to validate the in vitro results, in vivo analysis was performed using 4T1-syngeneic mouse model.

KEY FINDINGS

In this study, we report that the dietary isoflavone genistein (GN) synergistically improved antineoplasticity of CC in breast cancer by arresting cells at G2/M phase culminating in ROS dependent apoptosis. The combination of CC plus GN caused dysregulation of Bax and Bcl-2 ratio inducing mitochondrial dysfunction, activation of Caspase-3/7, -9 and PARP cleavage. Further, combination significantly suppresses phosphorylation of PI3K/Akt/NF-κB, enhancing apoptosis. Additionally, combination markedly reduced tumor growth compared to CC and GN alone in mouse 4T1 breast tumor model.

SIGNIFICANCE

Together, these studies suggest that GN represents a potential adjunct molecule whose role in CC induced apoptosis deserves attention.

Ormeloxifene nanotherapy for cervical cancer treatment

BACKGROUND

Cervical cancer (CxCa) ranks as the fourth most prevalent women-related cancer worldwide. Therefore, there is a crucial need to develop newer treatment modalities. Ormeloxifene (ORM) is a non-steroidal, selective estrogen receptor modulator (SERM) that is used as an oral contraceptive in humans. Recent investigations suggest that ORM exhibits potent anti-cancer activity against various types of cancers. Nanoparticulates offer targeted delivery of anti-cancer drugs with minimal toxicity and promise newer approaches for cancer diagnosis and treatment. Therefore, the nanotherapy approach is superior compared to traditional chemotherapy, which is not site-specific and is often associated with various side effects.

METHODS

Pursuing this novel nanotherapy approach, our lab has recently developed ORM-loaded poly [lactic-co-glycolic acid] (PLGA), an FDA-approved biodegradable polymer, nanoparticles to achieve targeted drug delivery and improved bioavailability. Our optimized PLGA-ORM nanoformulation showed improved internalization in both dose- and energy-dependent manners, through endocytosis-mediated pathways in both Caski and SiHa cell lines. Additionally, we employed MTS and colony forming assays to determine the short- and long-term effects of PLGA-ORM on these cells.

RESULTS

Our results showed that this formulation demonstrated improved inhibition of cellular proliferation and clonogenic potential compared to free ORM. Furthermore, the PLGA-ORM nanoformulation exhibited superior anti-tumor activities in an orthotopic cervical cancer mouse model than free ORM.

CONCLUSION

Collectively, our findings suggest that our novel nanoformulation has great potential for repurposing the drug and becoming a novel modality for CxCa management.

A triphenylethylene nonsteroidal SERM attenuates cervical cancer growth

Selective estrogen receptor modulator drug molecules of triphenylethylene family have gained considerable attention as anti-cancer agents. Despite recent advances in screening and development of HPV vaccines, cervical cancer remains one of the deadliest malignancies as advanced stage metastatic disease is mostly untreatable, thus warrants newer therapeutic strategies. Ormeloxifene (ORM) is a well-known SERM of triphenylethylene family that has been approved for human use, thus represents an ideal molecule for repurposing. In this study, we for the first time have demonstrated the anti-cancerous properties of ormeloxifene in cervical cancer. Ormeloxifene efficiently attenuated tumorigenic and metastatic properties of cervical cancer cells via arresting cell cycle at G1-S transition, inducing apoptosis, decreasing PI3K and Akt phosphorylation, mitochondrial membrane potential, and modulating G1-S transition related proteins (p21, cyclin E and Cdk2). Moreover, ORM repressed the expression of HPV E6/ E7 oncoproteins and restored the expression of their downstream target tumor suppressor proteins (p53, Rb and PTPN 13). As a result, ormeloxifene induces radio-sensitization in cervical cancer cells and caused potent tumor growth inhibition in orthotopic mouse model. Taken together, ormeloxifene represents an alternative therapeutic modality for cervical cancer which may have rapid clinical translation as it is already proven safe for human use.

Ormeloxifene-induced unfolded protein response contributes to autophagy-associated apoptosis via disruption of Akt/mTOR and activation of JNK

Autophagy, a regulated nutrient recycling program can affect both cell survival and cell death. Here, we show that Ormeloxifene (ORM), a selective estrogen receptor modulator approved for oral contraceptive use induces autophagic flux in ovarian cancer cells, which is activated by an ER stress response upstream of autophagy. The ER stress response is characterized by activation of IRE1α, PERK and ATF6 and is under regulation of JNK. Pharmacological inhibition of either autophagy or ER stress increased cell survival, as did silencing of autophagy proteins LC3 and Beclin 1, implying that ORM-induced autophagy is pro-death in nature. Ultrastructural observations of treated cells confirmed stages of autophagic maturation. Caspase-dependent apoptosis succeeded these events and was characterized by generation of reactive oxygen species and disruption of mitochondrial membrane potential. A concomitant inhibition of the Akt/mTOR axis was also observed with possible regulation of Akt by ORM. ORM inhibited tumor growth in ovarian xenograft model and displayed autophagic activity. In summary, in vitro and in vivo results reveal that ORM induces autophagy-associated cell death to attenuate proliferation of ovarian cancer cells. Our results demonstrate that using ORM in combination with ER stress and autophagy modulators could offer better therapeutic outcome in ovarian cancer.

Dietary isoflavone daidzein synergizes centchroman action via induction of apoptosis and inhibition of PI3K/Akt pathway in MCF-7/MDA MB-231 human breast cancer cells

BACKGROUND

Despite advancements in the prognosis and management of breast cancer, it remains a major cause of mortality in women worldwide. Centchroman (CC), an oral contraceptive has been found to exhibit anti-cancer potential against a wide range of cancer including breast cancer.

PURPOSE

The present study is intended to evaluate the ability of soy isoflavone Daidzein (DZ) in enhancing the efficacy of CC in Human Breast Cancer Cells (HBCCs).

METHODS/STUDY DESIGN

Sulforhodamine B assay was employed to determine the cytotoxicity induced by 10 µM CC & 50 µM DZ separately and together in MCF-7/MDA MB-231 HBCCs and non-tumorigenic Human Mammary Epithelial Cells (HMECs) MCF-10A as a control. Combination Index (CI) analysis was executed using CompuSyn software. Further, apoptosis was assessed using Annexin V/PI, AO/PI staining and tunel assay. Cell cycle, reactive oxygen species generation and mitochondrial membrane potential alteration was determined using flow cytometry. Western blot analysis was performed to check the expression of respective proteins.

RESULTS

The results suggest that the combination exerts elevated toxicity as compared to control and each drug per se without affecting HMECs MCF-10A. This therefore implies cancer cell specific action of CC plus DZ administered together. Additionally, combination index analysis suggests synergistic action of CC and DZ combination in HBCCs. Cell cycle analysis, Annexin V/PI staining, tunel assay and western blot analysis confirms the induction of apoptosis by combination in HBCCs. Interestingly, western blot analysis also revealed that the combination down-regulated the expression of proteins involved in cell survival i.e. PI3K, Akt and mTOR, suggesting inhibition of cell survival pathway.

CONCLUSION

The results overall demonstrate that CC plus DZ has higher anticancer efficacy as compared to either drug alone. Hence, the combination of CC plus DZ may offer a novel strategy for the management of breast cancer.

Ormeloxifene Suppresses Prostate Tumor Growth and Metastatic Phenotypes via Inhibition of Oncogenic β-catenin Signaling and EMT Progression

Ormeloxifene is a clinically approved selective estrogen receptor modulator, which has also shown excellent anticancer activity, thus it can be an ideal repurposing pharmacophore. Herein, we report therapeutic effects of ormeloxifene on prostate cancer and elucidate a novel molecular mechanism of its anticancer activity. Ormeloxifene treatment inhibited epithelial-to-mesenchymal transition (EMT) process as evident by repression of N-cadherin, Slug, Snail, vimentin, MMPs (MMP2 and MMP3), β-catenin/TCF-4 transcriptional activity, and induced the expression of pGSK3β. In molecular docking analysis, ormeloxifene showed proficient docking with β-catenin and GSK3β. In addition, ormeloxifene induced apoptosis, inhibited growth and metastatic potential of prostate cancer cells and arrested cell cycle in G₀-G₁ phase via modulation of cell-cycle regulatory proteins (inhibition of Mcl-1, cyclin D1, and CDK4 and induction of p21 and p27). In functional assays, ormeloxifene remarkably reduced tumorigenic, migratory, and invasive potential of prostate cancer cells. In addition, ormeloxifene treatment significantly (P < 0.01) regressed the prostate tumor growth in the xenograft mouse model while administered through intraperitoneal route (250 μg/mouse, three times a week). These molecular effects of ormeloxifene were also observed in excised tumor tissues as shown by immunohistochemistry analysis. Our results, for the first time, demonstrate repurposing potential of ormeloxifene as an anticancer drug for the treatment of advanced stage metastatic prostate cancer through a novel molecular mechanism involving β-catenin and EMT pathway. Mol Cancer Ther; 16(10); 2267-80. ©2017 AACR.

5-lipoxygenase mediates docosahexaenoyl ethanolamide and N-arachidonoyl-L-alanine-induced reactive oxygen species production and inhibition of proliferation of head and neck squamous cell carcinoma cells

Background

Endocannabinoids have recently drawn attention as promising anti-cancer agents. We previously observed that anandamide (AEA), one of the representative endocannabinoids, effectively inhibited the proliferation of head and neck squamous cell carcinoma (HNSCC) cell lines in a receptor-independent manner. In this study, using HNSCC cell lines, we examined the anti-cancer effects and the mechanisms of action of docosahexaenoyl ethanolamide (DHEA) and N-arachidonoyl-L-alanine (NALA), which are polyunsaturated fatty acid (PUFA)-based ethanolamides like AEA.

Methods and Results

DHEA and NALA were found to effectively inhibit HNSCC cell proliferation. These anti-proliferative effects seemed to be mediated in a cannabinoid receptor-independent manner, since the antagonist of cannabinoid receptor-1 (CB1) and vanilloid receptor-1 (VR1), two endocannabinoid receptors, did not reverse the ability of DHEA and NALA to induce cell death. Instead, we observed an increase in reactive oxygen species (ROS) production and a decrease of phosphorylated Akt as a result of DHEA and NALA treatment. Antioxidants efficiently reversed the inhibition of cell proliferation and the decrease of phosphorylated Akt induced by DHEA and NALA; inhibition of 5-lipoxygenase (5-LO), which is expected to be involved in DHEA- and NALA-degradation pathway, also partially blocked the ability of DHEA and NALA to inhibit cell proliferation and phosphorylated Akt. Interestingly, ROS production as a result of DHEA and NALA treatment was decreased by inhibition of 5-LO.

Conclusions

From these findings, we suggest that ROS production induced by the 5-LO pathway mediates the anti-cancer effects of DHEA and NALA on HNSCC cells. Finally, our findings suggest the possibility of a new cancer-specific therapeutic strategy, which utilizes 5-LO activity rather than inhibiting it.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2499-3) contains supplementary material, which is available to authorized users.

Inhibition of NADPH Oxidase-4 Potentiates 2-Deoxy-D-Glucose-Induced Suppression of Glycolysis, Migration, and Invasion in Glioblastoma Cells: Role of the Akt/HIF1α/HK-2 Signaling Axis

AIMS

2-Deoxy-d-glucose (2-DG), a synthetic glycolytic inhibitor, is currently under clinical evaluation as a promising anticancer agent. However, 2-DG treatment in cancer cells activates prosurvival Akt signaling that might limit its clinical efficacy. The NADPH oxidase 4 (Nox-4)/reactive oxygen species/Akt signaling is known to regulate survival, proliferation, infiltration, and invasion in glioblastomas (GBMs). The enhanced motility, invasiveness, and therapy resistance in GBMs are attributed to metabolic adaptation through increased aerobic glycolysis. Therefore, we hypothesized that inhibition of the Nox-4 might enhance 2-DG-induced suppression of glycolysis, migration, and invasion in GBM cells.

RESULTS

We identified the natural naphthoquinone compound shikonin as a potent inhibitor of the Nox-4/Akt signaling pathway. The combined treatment of shikonin+2-DG suppressed the glycolytic phenotype, migration, and invasion through modulation of the Akt/HIF1α/hexokinase-2 signaling axis in GBM cells. The combination also exhibited enhanced antiproliferative and antiangiogenic effects in vivo.

INNOVATION

Our data for the first time demonstrate that inhibition of the Nox-4-associated prosurvival signaling pathway by shikonin enhances the antiproliferative and antiangiogenic potential of 2-DG in GBM cells.

CONCLUSION

In summary, the combined inhibition of Nox-4 and glycolysis may have therapeutic implications for the management of GBMs.

Shikonin selectively induces apoptosis in human prostate cancer cells through the endoplasmic reticulum stress and mitochondrial apoptotic pathway

Background

Despite the recent progress in screening and therapy, a majority of prostate cancer cases eventually attain hormone refractory and chemo-resistant attributes. Conventional chemotherapeutic strategies are effective at very high doses for only palliative management of these prostate cancers. Therefore chemo-sensitization of prostate cancer cells could be a promising strategy for increasing efficacy of the conventional chemotherapeutic agents in prostate cancer patients. Recent studies have indicated that the chemo-preventive natural agents restore the pro-apoptotic protein expression and induce endoplasmic reticulum stress (ER stress) leading to the inhibition of cellular proliferation and activation of the mitochondrial apoptosis in prostate cancer cells. Therefore reprogramming ER stress-mitochondrial dependent apoptosis could be a potential approach for management of hormone refractory chemoresistant prostate cancers. We aimed to study the effects of the natural naphthoquinone Shikonin in human prostate cancer cells.

Results

The results indicated that Shikonin induces apoptosis in prostate cancer cells through the dual induction of the endoplasmic reticulum stress and mitochondrial dysfunction. Shikonin induced ROS generation and activated ER stress and calpain activity. Moreover, addition of antioxidants attenuated these effects. Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.

Conclusion

The results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-015-0127-1) contains supplementary material, which is available to authorized users.

Nanoparticle formulation of ormeloxifene for pancreatic cancer

Pancreatic cancer is the fourth most prevalent cancer with about an 85% mortality rate; thus, an utmost need exists to discover new therapeutic modalities that would enhance therapy outcomes of this disease with minimal or no side effects. Ormeloxifene (ORM), a synthetic molecule, has exhibited potent anti-cancer effects through inhibition of important oncogenic and proliferation signaling pathways. However, the anti-cancer efficacy of ORM can be further improved by developing its nanoformulation, which will also offer tumor specific targeted delivery. Therefore, we have developed a novel ORM encapsulated poly(lactic-co-glycolic acid) nanoparticle (NP) formulation (PLGA-ORM NP). This formulation was characterized for particle size, chemical composition, and drug loading efficiency, using various physico-chemical methods (TEM, FT-IR, DSC, TGA, and HPLC). Because of its facile composition, this novel formulation is compatible with antibody/aptamer conjugation to achieve tumor specific targeting. The particle size analysis of this PLGA-ORM formulation (∼100 nm) indicates that this formulation can preferentially reach and accumulate in tumors by the Enhanced Permeability and Retention (EPR) effect. Cellular uptake and internalization studies demonstrate that PLGA-ORM NPs escape lysosomal degradation, providing efficient endosomal release to cytosol. PLGA-ORM NPs showed remarkable anti-cancer potential in various pancreatic cancer cells (HPAF-II, AsPC-1, BxPC-3, Panc-1, and MiaPaca) and a BxPC-3 xenograft mice model resulting in increased animal survival. PLGA-ORM NPs suppressed pancreatic tumor growth via suppression of Akt phosphorylation and expression of MUC1, HER2, PCNA, CK19 and CD31. This study suggests that the PLGA-ORM formulation is highly efficient for the inhibition of pancreatic tumor growth and thus can be valuable for the treatment of pancreatic cancer in the future.

Liquid phase collagen modified graphene that induces apoptosis

The differential interference contrast (DIC) and fluorescence confocal micrographs show collagen microfibrils attacking graphite from all sides to form a stable dispersion of collagen modified graphene, but only collagen picks up a stain.

Centchroman suppresses breast cancer metastasis by reversing epithelial-mesenchymal transition via downregulation of HER2/ERK1/2/MMP-9 signaling

Metastatic spread during carcinogenesis worsens disease prognosis and accelerates the cancer progression. Therefore, newer therapeutic options with higher specificity toward metastatic cancer are required. Centchroman (CC), a female oral contraceptive, has previously been reported to possess antiproliferative and proapoptotic activities in human breast cancer cells. Here, we investigated the effect of CC-treatment against breast cancer metastasis and associated molecular mechanism using in vitro and in vivo models. CC significantly inhibited the proliferation of human and mouse mammary cancer cells. CC-treatment also inhibited migration and invasion capacities of highly metastatic MDA-MB-231 and 4T1 cells, at sub-IC50 concentrations. Inhibition of cell migration and invasion was found to be associated with the reversal of epithelial-to-mesenchymal transition (EMT) as observed by the upregulation of epithelial markers and downregulation of mesenchymal markers as well as decreased activities of matrix metalloproteinases. Experimental EMT induced by exposure to TGFβ/TNFα in nontumorigenic human mammary epithelial MCF10A cells was also reversed by CC as evidenced by morphological changes and modulation in the expression levels of EMT-markers. CC-mediated inhibition of cellular migration was, at least partially, mediated through inhibition of ERK1/2 signaling, which was further validated by using MEK1/2 inhibitor (PD0325901). Furthermore, CC-treatment resulted in suppression of tumor growth and lung metastasis in 4T1-syngeneic mouse model. Collectively, our findings suggest that CC-treatment at higher doses specifically induces cellular apoptosis and inhibits cellular proliferation; whereas at lower doses, it inhibits cellular migration and invasion. Therefore, CC could further be developed as an effective drug candidate against metastatic breast cancer.

Co‑culture with human fetal epidermal keratinocytes promotes proliferation and migration of human fetal and adult dermal fibroblasts

The repair strategy for the healing of skin wounds in fetuses differs from that in adults. Proliferation and migration of dermal fibroblasts are the main mechanisms associated with skin wound healing, as well as the complex interactions between epidermal keratinocytes (KCs) and dermal fibroblasts. In order to investigate the effects of fetal skin epidermal KCs on fetal and adult human dermal fibroblasts, KCs and fibroblasts were isolated from the skin tissue of mid‑gestational human fetuses and adults, and co‑cultured using a Transwell® system. When fetal mid‑gestational KCs were co‑cultured with either fetal or adult dermal fibroblasts, the proliferative and migratory potential of the fibroblasts was significantly enhanced. Furthermore, these phenotypic changes were concomitant with the upregulation of numerous proteins including mouse double minute 2 homolog, cyclin B1, phospho‑cyclin‑dependent kinase 1, phospho‑extracellular signal‑regulated kinase, and phospho‑AKT, along with C‑X‑C chemokine receptor 4, phospho‑p38 mitogen activated protein kinase, matrix metalloproteinase (MMP)‑2 and MMP‑9. Notably, no significant differences were observed between fetal and adult dermal fibroblasts in their responses to fetal mid‑gestational epidermal KCs, indicating that the cells from these two developmental stages respond in a similar manner to co‑culture with KCs.

Medicarpin, a legume phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the induction of DR5 and activation of the ROS-JNK-CHOP pathway

Tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent with cancer cell-selective cell death inducing effect. However, the major limitation in the usage of TRAIL as a chemotherapeutic agent is the development of TRAIL resistance in many cancer types including myeloid leukemia. In this study, we report for the first time that Medicarpin (Med), a naturally occurring phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis. Combination of Med and TRAIL induced significantly higher apoptosis compared with that of the individual treatments of either agent alone through activation of both the extrinsic and the intrinsic cell death pathways characterized by the activation of caspases 8, 9, 3, and 7. Med treatment downregulated antiapoptotic proteins (Survivin, Bcl2, Bcl-xL, XIAP, and c-FLIP), upregulated pro-apoptotic proteins (Bax, Cytochrome C, Smac/Diablo, Bid, truncated Bid (tBid), p-eIF2α, Bip, and CHOP (CCAAT-enhancer binding protein homologous protein)), induced G2/M cell-cycle arrest, and increased the expression of the functional TRAIL receptor DR5 through activation of the ROS-JNK-CHOP pathway. Gain and loss of function studies clearly indicated that DR5 expression was critical for Med-induced TRAIL sensitization. The Med-induced TRAIL sensitization did not involve the NFkB signaling pathway or redistribution of DR5 in lipid rafts. The concomitant treatment with Med and TRAIL showed robust apoptotic effects in primary myeloid leukemia cells but had no toxic effects in primary human peripheral blood mononuclear cells (PBMCs). In conclusion, our results suggest that Med sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the upregulation of DR5 through activation of the ROS-JNK-CHOP pathway.

Ormeloxifene efficiently inhibits ovarian cancer growth

Ovarian cancer continues to be a leading cause of cancer related deaths for women. Anticancer agents effective against chemo-resistant cells are greatly needed for ovarian cancer treatment. Repurposing drugs currently in human use is an attractive strategy for developing novel cancer treatments with expedited translation into clinical trials. Therefore, we examined whether ormeloxifene (ORM), a non-steroidal Selective Estrogen Receptor Modulator (SERM) currently used for contraception, is therapeutically effective at inhibiting ovarian cancer growth. We report that ORM treatment inhibits cell growth and induces apoptosis in ovarian cancer cell lines, including cell lines resistant to cisplatin. Furthermore, ORM treatment decreases Akt phosphorylation, increases p53 phosphorylation, and modulates the expression and localization patterns of p27, cyclin E, cyclin D1, and CDK2. In a pre-clinical xenograft mouse ORM treatment significantly reduces tumorigenesis and metastasis. These results indicate that ORM effectively inhibits the growth of cisplatin resistant ovarian cancer cells. ORM is currently in human use and has an established record of patient safety. Our encouraging in vitro and pre-clinical in vivo findings indicate that ORM is a promising candidate for the treatment of ovarian cancer.

Anti-cancer potential of a novel SERM ormeloxifene

Ormeloxifene is a non-steroidal Selective Estrogen Receptor Modulator (SERM) that is used as an oral contraceptive. Recent studies have shown its potent anti-cancer activities in breast, head and neck, and chronic myeloid leukemia cells. Several in vivo and clinical studies have reported that ormeloxifene possesses an excellent therapeutic index and has been well-tolerated, without any haematological, biochemical or histopathological toxicity, even with chronic administration. A reasonably long period of time and an enormous financial commitment are required to develop a lead compound into a clinically approved anti-cancer drug. For these reasons and to circumvent these obstacles, ormeloxifene is a promising candidate on a fast track for the development or repurposing established drugs as anti-cancer agents for cancer treatment. The current review summarizes recent findings on ormeloxifene as an anti-cancer agent and future prospects of this clinically safe pharmacophore.

Blockade of glioma proliferation through allosteric inhibition of JAK2

The gene that encodes the epidermal growth factor receptor (EGFR) is frequently overexpressed or mutated in human cancers, including glioblastoma. However, the efficacy of EGFR-targeted small-molecule inhibitors or monoclonal antibodies in glioblastomas that also have mutation or deletion of the gene encoding phosphatase and tensin homolog (PTEN) has been modest. We found that EGFR signaling was blocked by a small molecule (G5-7) that selectively inhibited Janus kinase 2 (JAK2)-mediated phosphorylation and activation of EGFR and STAT3 (signal transducer and activator of transcription 3) by binding to JAK2, thereby decreasing the activity of downstream signaling by mTOR (mammalian target of rapamycin) and inducing cell cycle arrest. G5-7 inhibited the proliferation of PTEN-deficient glioblastoma cell lines harboring a constitutively active variant of EGFR (U87MG/EGFRvIII) and human glioblastoma explant neurosphere cultures, but the drug only weakly inhibited the proliferation of either glioblastoma cell lines that were wild type for EGFR and stably transfected with PTEN (U87MG/PTEN) or normal neural progenitor cells and astrocytes. Additionally, G5-7 reduced vascular endothelial growth factor (VEGF) secretion and endothelial cell migration and induced apoptosis in glioblastoma xenografts, thereby suppressing glioblastoma growth in vivo. Furthermore, G5-7 was more potent than EGFR or JAK2 inhibitors that interfere with either ligand or adenosine 5'-triphosphate (ATP) binding at impeding glioblastoma cell proliferation, demonstrating that this allosteric JAK2 inhibitor may be an effective clinical strategy.

Co-culture with Sertoli cells promotes proliferation and migration of umbilical cord mesenchymal stem cells

Human umbilical cord mesenchymal stem cells (hUCMSCs) have been recently used in transplant therapy. The proliferation and migration of MSCs are the determinants of the efficiency of MSC transplant therapy. Sertoli cells are a kind of "nurse" cells that support the development of sperm cells. Recent studies show that Sertoli cells promote proliferation of endothelial cells and neural stem cells in co-culture. We hypothesized that co-culture of UCMSCs with Sertoli cells may also promote proliferation and migration of UCMSCs. To examine this hypothesis, we isolated UCMSCs from human cords and Sertoli cells from mouse testes, and co-cultured them using a Transwell system. We found that UCMSCs exhibited strong proliferation ability and potential to differentiate to other cell lineages such as osteocytes and adipocytes. The presence of Sertoli cells in co-culture significantly enhanced the proliferation and migration potential of UCMSCs (P<0.01). Moreover, these phenotypic changes were accompanied with upregulation of multiple genes involved in cell proliferation and migration including phospho-Akt, Mdm2, phospho-CDC2, Cyclin D1, Cyclin D3 as well as CXCR4, phospho-p44 MAPK and phospho-p38 MAPK. These findings indicate that Sertoli cells boost UCMSC proliferation and migration potential.