Lovastatin induces apoptosis of ovarian cancer cells and synergizes with doxorubicin: potential therapeutic relevance

Overcoming statin resistance in prostate cancer cells by targeting the 3-hydroxy-3-methylglutaryl-CoA-reductase

Prostate cancer is the most prevalent malignancy in men. While diagnostic and therapeutic interventions have substantially improved in recent years, disease relapse, treatment resistance, and metastasis remain significant contributors to prostate cancer-related mortality. Therefore, novel therapeutic approaches are needed. Statins are inhibitors of the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway which plays an essential role in cholesterol homeostasis. Numerous preclinical studies have provided evidence for the pleiotropic antitumor effects of statins. However, results from clinical studies remain controversial and have shown substantial benefits to even no effects on human malignancies including prostate cancer. Potential statin resistance mechanisms of tumor cells may account for such discrepancies. In our study, we treated human prostate cancer cell lines (PC3, C4-2B, DU-145, LNCaP) with simvastatin, atorvastatin, and rosuvastatin. PC3 cells demonstrated high statin sensitivity, resulting in a significant loss of vitality and clonogenic potential (up to - 70%; p < 0.001) along with an activation of caspases (up to 4-fold; p < 0.001). In contrast, C4-2B and DU-145 cells were statin-resistant. Statin treatment induced a restorative feedback in statin-resistant C4-2B and DU-145 cells through upregulation of the HMGCR gene and protein expression (up to 3-folds; p < 0.01) and its transcription factor sterol-regulatory element binding protein 2 (SREBP-2). This feedback was absent in PC3 cells. Blocking the feedback using HMGCR-specific small-interfering (si)RNA, the SREBP-2 activation inhibitor dipyridamole or the HMGCR degrader SR12813 abolished statin resistance in C4-2B and DU-145 and induced significant activation of caspases by statin treatment (up to 10-fold; p < 0.001). Consistently, long-term treatment with sublethal concentrations of simvastatin established a stable statin resistance of a PC3SIM subclone accompanied by a significant upregulation of both baseline as well as post-statin HMGCR protein (gene expression up to 70-fold; p < 0.001). Importantly, the statin-resistant phenotype of PC3SIM cells was reversible by HMGCR-specific siRNA and dipyridamole. Our investigations reveal a key role of a restorative feedback driven by the HMGCR/SREBP-2 axis in statin resistance mechanisms of prostate cancer cells.

Causal association between lipid-lowering drugs and female reproductive endocrine diseases: a drug-targeted Mendelian randomization study

Purpose

The relationship between dyslipidemia and female reproductive endocrine diseases has been increasingly studied. The use of lipid-lowering drugs in treating various related diseases, including coronary heart disease, may affect female reproductive endocrine diseases. Therefore, our study aims to investigate the effects of lipid-lowering drugs on female reproductive endocrine diseases and provide a basis for the appropriate selection of drugs.

Methods

In this study, we focused on three drug targets of statins, namely HMG-CoA reductase (HMGCR) inhibitors, proprotein convertase kexin 9 (PCSK9) inhibitors, and Niemann-Pick C1-Like 1 (NPC1L1) inhibitors. To identify potential inhibitors for these targets, we collected single nucleotide polymorphisms (SNPs) associated with HMGCR, PCSK9, and NPC1L1 from published genome-wide association study statistics. Subsequently, we conducted a drug target Mendelian randomization (MR) analysis to investigate the effects of these inhibitors on reproductive endocrine diseases mediated by low-density lipoprotein cholesterol (LDL-C) levels. Alongside coronary heart disease as a positive control, our main outcomes of interest included the risk of polycystic ovary syndrome (PCOS), premature ovarian insufficiency (POI), premenstrual syndrome (PMS), abnormal uterine bleeding (including menorrhagia and oligomenorrhea), and infertility.

Results

PCSK9 inhibitors significantly increased the risk of infertility in patients (OR [95%CI] = 1.14 [1.06, 1.23], p<0.05). In contrast, HMGCR inhibitors significantly reduced the risk of menorrhagia in female patients (OR [95%CI] = 0.85 [0.75, 0.97], p<0.05), but had no statistical impact on patients with oligomenorrhea.

Conclusion

The findings suggest that PCSK9 inhibitors may significantly increase the risk of infertility in patients. On the other hand, HMGCR inhibitors could potentially offer protection against menorrhagia in women. However, no effects of lipid-lowering drugs have been observed on other reproductive endocrine disorders, such as PCOS, POF, PMS and oligomenorrhea.

Rhabdomyosarcoma: Current Therapy, Challenges, and Future Approaches to Treatment Strategies

Rhabdomyosarcoma is a rare cancer arising in skeletal muscle that typically impacts children and young adults. It is a worldwide challenge in child health as treatment outcomes for metastatic and recurrent disease still pose a major concern for both basic and clinical scientists. The treatment strategies for rhabdomyosarcoma include multi-agent chemotherapies after surgical resection with or without ionization radiotherapy. In this comprehensive review, we first provide a detailed clinical understanding of rhabdomyosarcoma including its classification and subtypes, diagnosis, and treatment strategies. Later, we focus on chemotherapy strategies for this childhood sarcoma and discuss the impact of three mechanisms that are involved in the chemotherapy response including apoptosis, macro-autophagy, and the unfolded protein response. Finally, we discuss in vivo mouse and zebrafish models and in vitro three-dimensional bioengineering models of rhabdomyosarcoma to screen future therapeutic approaches and promote muscle regeneration.

Cell-cycle arrest at the G1/S boundary enhances transient voltage-gated ion channel expression in human and insect cells

Heterologous expression of recombinant ion channel subunits in cell lines is often limited by the presence of a low number of channels at the cell surface level. Here, we introduce a combination of two techniques: viral expression using the baculovirus system plus cell-cycle arrest at the G1/S boundary using either thymidine or hydroxyurea. This method achieved a manifold increase in the peak current density of expressed ion channels compared with the classical liposome-mediated transfection methods. The enhanced ionic current was accompanied by an increase in the density of gating charges, confirming that the increased yield of protein and ionic current reflects the functional localization of channels in the plasma membrane. This modified method of viral expression coordinated with the cell cycle arrest will pave the way to better decipher the structure and function of ion channels and their association with ion channelopathies.

Repositioning of HMG-CoA Reductase Inhibitors as Adjuvants in the Modulation of Efflux Pump-Mediated Bacterial and Tumor Resistance

Efflux pump (EP)-mediated multidrug resistance (MDR) seems ubiquitous in bacterial infections and neoplastic diseases. The diversity and lack of specificity of these efflux mechanisms raise a great obstacle in developing drugs that modulate efflux pumps. Since developing novel chemotherapeutic drugs requires large investments, drug repurposing offers a new approach that can provide alternatives as adjuvants in treating resistant microbial infections and progressive cancerous diseases. Hydroxy-methyl-glutaryl coenzyme-A (HMG-CoA) reductase inhibitors, also known as statins, are promising agents in this respect. Originally, statins were used in the therapy of dyslipidemia and for the prevention of cardiovascular diseases; however, extensive research has recently been performed to elucidate the functions of statins in bacterial infections and cancers. The mevalonate pathway is essential in the posttranslational modification of proteins related to vital eukaryotic cell functions. In this article, a comparative review is given about the possible role of HMG-CoA reductase inhibitors in managing diseases of bacterial and neoplastic origin. Molecular research and clinical studies have proven the justification of statins in this field. Further well-designed clinical trials are urged to clarify the significance of the contribution of statins to the lower risk of disease progression in bacterial infections and cancerous diseases.

Metabolic modelling-based in silico drug target prediction identifies six novel repurposable drugs for melanoma

Despite high initial response rates to targeted kinase inhibitors, the majority of patients suffering from metastatic melanoma present with high relapse rates, demanding for alternative therapeutic options. We have previously developed a drug repurposing workflow to identify metabolic drug targets that, if depleted, inhibit the growth of cancer cells without harming healthy tissues. In the current study, we have applied a refined version of the workflow to specifically predict both, common essential genes across various cancer types, and melanoma-specific essential genes that could potentially be used as drug targets for melanoma treatment. The in silico single gene deletion step was adapted to simulate the knock-out of all targets of a drug on an objective function such as growth or energy balance. Based on publicly available, and in-house, large-scale transcriptomic data metabolic models for melanoma were reconstructed enabling the prediction of 28 candidate drugs and estimating their respective efficacy. Twelve highly efficacious drugs with low half-maximal inhibitory concentration values for the treatment of other cancers, which are not yet approved for melanoma treatment, were used for in vitro validation using melanoma cell lines. Combination of the top 4 out of 6 promising candidate drugs with BRAF or MEK inhibitors, partially showed synergistic growth inhibition compared to individual BRAF/MEK inhibition. Hence, the repurposing of drugs may enable an increase in therapeutic options e.g., for non-responders or upon acquired resistance to conventional melanoma treatments.

A Cross-Talk about Radioresistance in Lung Cancer-How to Improve Radiosensitivity According to Chinese Medicine and Medicaments That Commonly Occur in Pharmacies

Lung cancer is one of the most common cancers in the population and is characterized by non-specific symptoms that delay the diagnosis and reduce the effectiveness of oncological treatment. Due to the difficult placement of the tumor, one of the main methods of lung cancer treatment is radiotherapy, which damages the DNA of cancer cells, inducing their apoptosis. However, resistance to ionizing radiation may develop during radiotherapy cycles, leading to an increase in the number of DNA points of control that protect cells from apoptosis. Cancer stem cells are essential for radioresistance, and due to their ability to undergo epithelial-mesenchymal transition, they modify the phenotype, bypassing the genotoxic effect of radiotherapy. It is therefore necessary to search for new methods that could improve the cytotoxic effect of cells through new mechanisms of action. Chinese medicine, with several thousand years of tradition, offers a wide range of possibilities in the search for compounds that could be used in conventional medicine. This review introduces the potential candidates that may present a radiosensitizing effect on lung cancer cells, breaking their radioresistance. Additionally, it includes candidates taken from conventional medicine-drugs commonly available in pharmacies, which may also be significant candidates.

Regulation of Autophagy via Carbohydrate and Lipid Metabolism in Cancer

Metabolic changes are an important component of tumor cell progression. Tumor cells adapt to environmental stresses via changes to carbohydrate and lipid metabolism. Autophagy, a physiological process in mammalian cells that digests damaged organelles and misfolded proteins via lysosomal degradation, is closely associated with metabolism in mammalian cells, acting as a meter of cellular ATP levels. In this review, we discuss the changes in glycolytic and lipid biosynthetic pathways in mammalian cells and their impact on carcinogenesis via the autophagy pathway. In addition, we discuss the impact of these metabolic pathways on autophagy in lung cancer.

Lovastatin inhibits erythroleukemia progression through KLF2-mediated suppression of MAPK/ERK signaling

BACKGROUND

Lovastatin, an HMG-CoA inhibitor and an effective cholesterol lowering drug, exhibits anti-neoplastic activity towards several types of cancer, although the underlying mechanism is still not fully understood. Herein, we investigated mechanism of growth inhibition of leukemic cells by lovastatin.

METHODS

RNAseq analysis was used to explore the effect of lovastatin on gene expression in leukemic cells. An animal model of leukemia was used to test the effect of this statin in vivo. FAM83A and DDIT4 expression was knocked-downed in leukemia cells via lentivirus-shRNA. Western blotting, RT-qPCR, cell cycle analysis and apoptosis assays were used to determine the effect of lovastatin-induced growth suppression in leukemic cells in vitro.

RESULTS

Lovastatin treatment strongly inhibited cancer progression in a mouse model of erythroleukemia induced by Friend virus. In tissue culture, lovastatin inhibited cell proliferation through induction of G₁ phase cell cycle arrest and apoptosis. Interestingly, lovastatin induced most known genes associated with cholesterol biosynthesis in leukemic cells. Moreover, it suppressed ERK1/2 phosphorylation by downregulating FAM83A and DDIT4, two mediators of MAP-Kinase signaling. RNAseq analysis of lovastatin treated leukemic cells revealed a strong induction of the tumor suppressor gene KLF2. Accordingly, lentivirus-mediated knockdown of KLF2 antagonized leukemia cell suppression induced by lovastatin, associated with higher ERK1/2 phosphorylation compared to control. We further show that KLF2 induction by lovastatin is responsible for lower expression of the FAM83A and DDIT4 oncogenes, involved in the activation of ERK1/2. KLF2 activation by lovastatin also activated a subset of cholesterol biosynthesis genes that may further contribute to leukemia suppression.

CONCLUSIONS

These results implicate KLF2-mediated FAM83A/DDIT4/MAPK suppression and activation of cholesterol biosynthesis as the mechanism of leukemia cell growth inhibition by lovastatin.

Advances in ovarian cancer treatment using a combination of statins with other drugs

New anti-cancer drugs are constantly being developed, especially targeted drugs. Although these drugs have achieved significant clinical efficacy, they do not play a significant role in ovarian cancer. Moreover, the research cycle and costs of such drugs are often huge. The repositioning of conventional drugs has gradually become a concern. Statins, as traditional lipid-lowering drugs, play a role mainly by inhibiting HMGCR. In recent years, epidemiological studies and in vitro experiments have confirmed its anti-cancer effect, especially the effect of anti-ovarian cancer. The mutation rate of TP53 in ovarian cancer is as high as 95%, while HMGCR is often highly expressed in TP53 mutant tumors. However, the effect of prospective clinical trials is not ideal. This result seems understandable considering that it seems unrealistic for a lipid-lowering drug to completely inhibit tumor growth. Therefore, statins play more synergistic roles in the treatment of ovarian cancer. Because ovarian cancer is a highly heterogeneous tumor, it may be a good choice to deeply understand the mechanism of statins in the treatment of ovarian cancer and achieve precise treatment by combining it with other drugs.

Repurposed Drugs in Gastric Cancer

Gastric cancer (GC) is one of the major causes of death worldwide, ranking as the fifth most incident cancer in 2020 and the fourth leading cause of cancer mortality. The majority of GC patients are in an advanced stage at the time of diagnosis, presenting a poor prognosis and outcome. Current GC treatment approaches involve endoscopic detection, gastrectomy and chemotherapy or chemoradiotherapy in an adjuvant or neoadjuvant setting. Drug development approaches demand extreme effort to identify molecular mechanisms of action of new drug candidates. Drug repurposing is based on the research of new therapeutic indications of drugs approved for other pathologies. In this review, we explore GC and the different drugs repurposed for this disease.

The Antineoplastic Effect of Carboplatin Is Potentiated by Combination with Pitavastatin or Metformin in a Chemoresistant High-Grade Serous Carcinoma Cell Line

The combination of Carboplatin with Paclitaxel is the mainstay treatment for high-grade serous carcinoma; however, many patients with advanced disease undergo relapse due to chemoresistance. Drug repurposing coupled with a combination of two or more compounds with independent mechanisms of action has the potential to increase the success rate of the antineoplastic treatment. The purpose of this study was to explore whether the combination of Carboplatin with repurposed drugs led to a therapeutic benefit. Hence, we assessed the cytotoxic effects of Carboplatin alone and in combination with several repurposed drugs (Pitavastatin, Metformin, Ivermectin, Itraconazole and Alendronate) in two tumoral models, i.e., Carboplatin (OVCAR8) and Carboplatin-Paclitaxel (OVCAR8 PTX R P) chemoresistant cell lines and in a non-tumoral (HOSE6.3) cell line. Cellular viability was measured using the Presto Blue assay, and the synergistic interactions were evaluated using the Chou-Talalay, Bliss Independence and Highest Single Agent reference models. Combining Carboplatin with Pitavastatin or Metformin displayed the highest cytotoxic effect and the strongest synergism among all combinations for OVCAR8 PTX R P cells, resulting in a chemotherapeutic effect superior to Carboplatin as a single agent. Concerning HOSE6.3 cells, combining Carboplatin with almost all the repurposed drugs demonstrated a safe pharmacological profile. Overall, we propose that Pitavastatin or Metformin could act synergistically in combination with Carboplatin for the management of high-grade serous carcinoma patients with a Carboplatin plus Paclitaxel resistance profile.

Statins as Repurposed Drugs in Gynecological Cancer: A Review

Discovering new drugs is an expensive and time-consuming process, including target identification, bioavailability, pharmacokinetic (PK) tests, pharmacodynamic (PD) tests, toxicity profiles, recommended dosage test, and observation of the side effects, etc. Repurposed drugs could bypass some steps, starting from phase II trials, and shorten the processes. Statins, also known as HMG-CoA inhibitors (HMGCR), are commonly used to manage and prevent various cardiovascular diseases and have been shown to improve the morbidity and mortality of patients. In addition to the inhibitory effects on the production of cholesterol, the beneficial effects of statins on the prognosis and risk of various cancers are also shown. Statins not only inhibited cell proliferation, metastasis, and chemoresistance but affected the tumor microenvironment (TME). Thus, statins have great potential to be repurposed in oncology. Hence, we review the meta-analysis, cohort, and case-control studies of statins in gynecological cancers, and elucidate how statins regulate cell proliferation, apoptosis, tumor growth, and metastasis. Although the results in gynecological cancers remain controversial and the effects of different statins in different histotypes of gynecological cancers and TME are needed to elucidate further, statins are excellent candidates and worthy of being repurposed drugs in treating gynecological cancers.

Computational pharmacogenomic screen identifies drugs that potentiate the anti-breast cancer activity of statins

Statins, a family of FDA-approved cholesterol-lowering drugs that inhibit the rate-limiting enzyme of the mevalonate metabolic pathway, have demonstrated anticancer activity. Evidence shows that dipyridamole potentiates statin-induced cancer cell death by blocking a restorative feedback loop triggered by statin treatment. Leveraging this knowledge, we develop an integrative pharmacogenomics pipeline to identify compounds similar to dipyridamole at the level of drug structure, cell sensitivity and molecular perturbation. To overcome the complex polypharmacology of dipyridamole, we focus our pharmacogenomics pipeline on mevalonate pathway genes, which we name mevalonate drug-network fusion (MVA-DNF). We validate top-ranked compounds, nelfinavir and honokiol, and identify that low expression of the canonical epithelial cell marker, E-cadherin, is associated with statin-compound synergy. Analysis of remaining prioritized hits led to the validation of additional compounds, clotrimazole and vemurafenib. Thus, our computational pharmacogenomic approach identifies actionable compounds with pathway-specific activities.

Pitavastatin and Ivermectin Enhance the Efficacy of Paclitaxel in Chemoresistant High-Grade Serous Carcinoma

Simple Summary

The main challenge in high-grade serous carcinoma management is to unveil therapeutic approaches to overcome chemoresistance. Drug combinations and repurposing of non-oncological agents are attractive strategies that allow for higher efficacy, decreased toxicity, and the overcoming of chemoresistance. Several non-oncological drugs display an effective anti-cancer activity and have been studied to be repurposed in multi-drug resistant neoplasms. The purpose of our study was to explore whether combining Paclitaxel with repurposed drugs (Pitavastatin, Metformin, Ivermectin, Itraconazole and Alendronate) led to a therapeutic benefit. Our results showed that the combination of Paclitaxel with Pitavastatin or Ivermectin demonstrates the highest cytotoxic effect and the strongest synergism among all combinations for two chemoresistant cell lines. Thus, the combination of these repurposed drugs with Paclitaxel could be a particularly valuable strategy to treat ovarian cancer patients with intrinsic or acquired chemoresistance.

Abstract

Chemotherapy is a hallmark in high-grade serous carcinoma management; however, chemoresistance and side effects lead to therapeutic interruption. Combining repurposed drugs with chemotherapy has the potential to improve antineoplastic efficacy, since drugs can have independent mechanisms of action and suppress different pathways simultaneously. This study aimed to explore whether the combination of Paclitaxel with repurposed drugs led to a therapeutic benefit. Thus, we evaluated the cytotoxic effects of Paclitaxel alone and in combination with several repurposed drugs (Pitavastatin, Metformin, Ivermectin, Itraconazole and Alendronate) in two tumor chemoresistant (OVCAR8 and OVCAR8 PTX R P) and a non-tumoral (HOSE6.3) cell lines. Cellular viability was assessed using Presto Blue assay, and the synergistic interactions were evaluated using Chou–Talalay, Bliss Independence and Highest Single Agent reference models. The combination of Paclitaxel with Pitavastatin or Ivermectin showed the highest cytotoxic effect and the strongest synergism among all combinations for both chemoresistant cell lines, resulting in a chemotherapeutic effect superior to both drugs alone. Almost all the repurposed drugs in combination with Paclitaxel presented a safe pharmacological profile in non-tumoral cells. Overall, we suggest that Pitavastatin and Ivermectin could act synergistically in combination with Paclitaxel, being promising two-drug combinations for high-grade serous carcinoma management.

Statins Increase the Bioavailability of Fixed-Dose Combination of Sofosbuvir/Ledipasvir by Inhibition of P-glycoprotein

BACKGROUND

Coadministration of statins and direct acting antiviral agents is frequently used. This study explored the effects of both atorvastatin and lovastatin on pharmacokinetics of a fixed-dose combination of sofosbuvir/ledipasvir "FDCSL".

METHODS

12 healthy volunteers participated in a randomized, three-phase crossover trial and were administered a single atorvastatin dose 80 mg plus tablet containing 400/90 mg FDCSL, a single lovastatin dose 40 mg plus tablet containing 400/90 mg FDCSL, or tablets containing 400/90 mg FDCSL alone. Liquid chromatography-tandem mass spectrometry was used to analyze plasma samples of sofosbuvir, ledipasvir and sofosbuvir metabolite "GS-331007" and their pharmacokinetic parameters were determined.

RESULTS

Atorvastatin caused a significant rise in sofosbuvir bioavailability as explained by increasing in AUC0-∞ and Cmax by 34.36% and 11.97%, respectively. In addition, AUC0-∞ and Cmax of GS-331007 were increased by 73.73% and 67.86%, respectively after atorvastatin intake. Similarly, co-administration of lovastatin with FDCSL increased the bioavailability of sofosbuvir, its metabolite (AUC0-∞ increase by 17.2%, 17.38%, respectively, and Cmax increase by 12.03%, 22.24%, respectively). However, neither atorvastatin nor lovastatin showed a change in ledipasvir bioavailability. Hepatic elimination was not affected after statin intake with FDCSL. Compared to lovastatin, atorvastatin showed significant increase in AUC0-∞ and Cmax of both sofosbuvir and its metabolite.

CONCLUSIONS

Both atorvastatin and lovastatin increased AUC of sofosbuvir and its metabolite after concurrent administration with FDCSL. Statins' P-glycoprotein inhibition is the attributed mechanism of interaction. The increase in sofosbuvir bioavailability was more pronounced after atorvastatin intake. Close monitoring is needed after co-administration of atorvastatin and FDCSL.

Targeting lipid metabolism in the treatment of ovarian cancer

Cancer cells undergo alterations in lipid metabolism to support their high energy needs, tumorigenesis and evade an anti-tumor immune response. Alterations in fatty acid production are controlled by multiple enzymes, chiefly Acetyl CoA Carboxylase, ATP-Citrate Lyase, Fatty Acid Synthase, and Stearoyl CoA Desaturase 1. Ovarian cancer (OC) is a common gynecological malignancy with a high rate of aggressive carcinoma progression and drug resistance. The accumulation of unsaturated fatty acids in ovarian cancer supports cell growth, increased cancer cell migration, and worse patient outcomes. Ovarian cancer cells also expand their lipid stores via increased uptake of lipids using fatty acid translocases, fatty acid-binding proteins, and low-density lipoprotein receptors. Furthermore, increased lipogenesis and lipid uptake promote chemotherapy resistance and dampen the adaptive immune response needed to eliminate tumors. In this review, we discuss the role of lipid synthesis and metabolism in driving tumorigenesis and drug resistance in ovarian cancer conferring poor prognosis and outcomes in patients. We also cover some aspects of how lipids fuel ovarian cancer stem cells, and how these metabolic alterations in intracellular lipid content could potentially serve as biomarkers of ovarian cancer.

Should mutant TP53 be targeted for cancer therapy?

Mutations in the TP53 tumour suppressor gene are found in ~50% of human cancers [1-6]. TP53 functions as a transcription factor that directly regulates the expression of ~500 genes, some of them involved in cell cycle arrest/cell senescence, apoptotic cell death or DNA damage repair, i.e. the cellular responses that together prevent tumorigenesis [1-6]. Defects in TP53 function not only cause tumour development but also impair the response of malignant cells to anti-cancer drugs, particularly those that induce DNA damage [1-6]. Most mutations in TP53 in human cancers cause a single amino acid substitution, usually within the DNA binding domain of the TP53 protein. These mutant TP53 proteins are often expressed at high levels in the malignant cells. Three cancer causing attributes have been postulated for mutant TP53 proteins: the inability to activate target genes controlled by wt TP53 (loss-of-function, LOF) that are critical for tumour suppression, dominant negative effects (DNE), i.e. blocking the function of wt TP53 in cells during early stages of transformation when mutant and wt TP53 proteins are co-expressed, and gain-of-function (GOF) effects whereby mutant TP53 impacts diverse cellular pathways by interacting with proteins that are not normally engaged by wt TP53 [1-6]. The GOF effects of mutant TP53 were reported to be essential for the sustained proliferation and survival of malignant cells and it was therefore proposed that agents that can remove mutant TP53 protein would have substantial therapeutic impact [7-9]. In this review article we discuss evidence for and against the value of targeting mutant TP53 protein for cancer therapy.

Drug repositioning: Progress and challenges in drug discovery for various diseases

Compared with traditional de novo drug discovery, drug repurposing has become an attractive drug discovery strategy due to its low-cost and high efficiency. Through a comprehensive analysis of the candidates that have been identified with drug repositioning potentials, it is found that although some drugs do not show obvious advantages in the original indications, they may exert more obvious effects in other diseases. In addition, some drugs have a synergistic effect to exert better clinical efficacy if used in combination. Particularly, it has been confirmed that drug repositioning has benefits and values on the current public health emergency such as the COVID-19 pandemic, which proved the great potential of drug repositioning. In this review, we systematically reviewed a series of representative drugs that have been repositioned for different diseases and illustrated successful cases in each disease. Especially, the mechanism of action for the representative drugs in new indications were explicitly explored for each disease, we hope this review can provide important insights for follow-up research.

Targeting TP53-Mutated Acute Myeloid Leukemia: Research and Clinical Developments

TP53 is a key tumor suppressor gene that plays an important role in regulating apoptosis, senescence, and DNA damage repair in response to cellular stress. Although somewhat rare, TP53-mutated AML has been identified as an important molecular subgroup with a prognosis that is arguably the worst of any. Survival beyond one year is rare after induction chemotherapy with or without consolidative allogeneic stem cell transplant. Although response rates have been improved with hypomethylating agents, outcomes remain particularly poor due to short response duration. Improvements in our understanding of AML genetics and biology have led to a surge in novel treatment options, though the clinical applicability of these agents in TP53-mutated disease remains largely unknown. This review will focus on the epidemiology, molecular characteristics, and clinical significance of TP53 mutations in AML as well as emerging treatment options that are currently being studied.

Statins and prostate cancer-hype or hope? The biological perspective

Growing evidence suggests that men prescribed a statin for cholesterol control have a lower risk of advanced prostate cancer (PCa) and improved treatment outcomes; however, the mechanism by which statins elicit their anti-neoplastic effects is not well understood and is likely multifaceted. Statins are potent and specific inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), the rate-limiting enzyme of the mevalonate (MVA) metabolic pathway. This two-part series is a review of the observational and experimental data on statins as anti-cancer agents in PCa. In this article, we describe the functional role that deregulated MVA metabolism plays in PCa progression and summarize the biological evidence and rationale for targeting the MVA pathway, with statins and other agents, for the treatment of PCa.

Cholesterol-Lowering Phytochemicals: Targeting the Mevalonate Pathway for Anticancer Interventions

There are a plethora of cancer causes and the road to fully understanding the carcinogenesis process remains a dream that keeps changing. However, a list of role players that are implicated in the carcinogens process is getting lengthier. Cholesterol is known as bad sterol that is heavily linked with cardiovascular diseases; however, it is also comprehensively associated with carcinogenesis. There is an extensive list of strategies that have been used to lower cholesterol; nevertheless, the need to find better and effective strategies remains vastly important. The role played by cholesterol in the induction of the carcinogenesis process has attracted huge interest in recent years. Phytochemicals can be dubbed as magic tramp cards that humans could exploit for lowering cancer-causing cholesterol. Additionally, the mechanisms that are regulated by phytochemicals can be targeted for anticancer drug development. One of the key role players in cancer development and suppression, Tumour Protein 53 (TP53), is crucial in regulating the biogenesis of cholesterol and is targeted by several phytochemicals. This minireview covers the role of p53 in the mevalonate pathway and how bioactive phytochemicals target the mevalonate pathway and promote p53-dependent anticancer activities.

miR-99b-5p, miR-380-3p, and miR-485-3p are novel chemosensitizing miRNAs in high-risk neuroblastoma

Neuroblastoma is a deadly childhood cancer arising in the developing sympathetic nervous system. High-risk patients are currently treated with intensive chemotherapy, which is curative in only 50% of children and leaves some surviving patients with life-long side effects. microRNAs (miRNAs) are critical regulators of neural crest development and are deregulated during neuroblastoma tumorigenesis, making miRNA-based drugs an attractive therapeutic avenue. A functional screen of >1,200 miRNA mimics was conducted in neuroblastoma cell lines to discover miRNAs that sensitized cells to low doses (30% inhibitory concentration [IC30]) of doxorubicin and vincristine chemotherapy used in the treatment of the disease. Three miRNAs, miR-99b-5p, miR-380-3p, and miR-485-3p, had potent chemosensitizing activity with doxorubicin in multiple models of high-risk neuroblastoma. These miRNAs underwent genomic loss in a subset of neuroblastoma patients, and low expression predicted poor survival outcome. In vitro functional assays revealed each of these miRNAs enhanced the anti-proliferative and pro-apoptotic effects of doxorubicin. We used RNA sequencing (RNA-seq) to show that miR-99b-5p represses neuroblastoma dependency genes LIN28B and PHOX2B both in vitro and in patient-derived xenograft (PDX) tumors. Luciferase reporter assays demonstrate that PHOX2B is a direct target of miR-99b-5p. We anticipate that restoring the function of the tumor-suppressive miRNAs discovered here may be a valuable therapeutic strategy for the treatment of neuroblastoma patients.

Gastric cancer cell death analyzed by live cell imaging of spheroids

Gastric cancer (GC) is the third cause of cancer-related mortality worldwide and is often diagnosed at advanced stages of the disease. This makes the development of more comprehensive models and efficient treatments crucial. One option is based on repurposing already marketed drugs as adjuvants to chemotherapy. Accordingly, we have previously developed the combination of docetaxel and the cholesterol-lowering drug, lovastatin, as a powerful trigger of HGT-1 human GC cells' apoptosis using 2D cultures. Because 3D models, known as spheroids, are getting recognized as possibly better suited than 2Ds in toxicological research, we aimed to investigate the efficacy of this drug combination with such a model. We established monocellular spheroids from two human (GC) cell lines, HGT-1 and AGS, and bicellular spheroids from these cells mixed with cancer-associated fibroblasts. With these, we surveyed drug-induced cytotoxicity with MTT assays. In addition, we used the Incucyte live imaging and analysis system to follow spheroid growth and apoptosis. Taken together, our results showed that the lovastatin + docetaxel combination was an efficient strategy to eliminate GC cells grown in 2D or 3D cultures, lending further support in favor of repurposing lovastatin as an adjuvant to taxane-based anticancer treatment.

Lovastatin enhances chemosensitivity of paclitaxel-resistant prostate cancer cells through inhibition of CYP2C8

Chemotherapy is the mainstay of treatment for prostate cancer, with paclitaxel being commonly used for hormone-resistant prostate cancer. However, drug resistance often develops and leads to treatment failure in a variety of prostate cancer patients. Therefore, it is necessary to enhance the sensitivity of prostate cancer to chemotherapy. Lovastatin (LV) is a natural compound extracted from Monascus-fermented foods and is an inhibitor of HMG-CoA reductase (HMGCR), which has been approved by the FDA for hyperlipidemia treatment. We have previously found that LV could inhibit the proliferation of refractory cancer cells. Up to now, the effect of LV on chemosensitization and the mechanisms involved have not been evaluated in drug-resistant prostate cancer. In this study, we used prostate cancer cell line PC3 and its paclitaxel-resistant counterpart PC3-TxR as the cell model. Alamar Blue cell viability assay showed that LV and paclitaxel each conferred concentration-dependent inhibition of PC3-TxR cells. When paclitaxel was combined with LV, the proliferation of PC3-TxR cells was synergistically inhibited, as demonstrated by combination index <1. Moreover, colony formation decreased while apoptosis increased in paclitaxel plus LV group compared with paclitaxel alone group. Quantitative RT-PCR showed that the combination of paclitaxel and LV could significantly reduce the expression of CYP2C8, an important drug-metabolizing enzyme. Bioinformatics analysis from the TCGA database showed that CYP2C8 expression was negatively correlated with progression-free survival (PFS) in prostate cancer patients. Our results suggest that LV might increase the sensitivity of resistant prostate cancer cells to paclitaxel through inhibition of CYP2C8 and could be utilized as a chemosensitizer for paclitaxel-resistant prostate cancer cells.

Fursultiamine Prevents Drug-Induced Ototoxicity by Reducing Accumulation of Reactive Oxygen Species in Mouse Cochlea

Drug-induced hearing loss is a major type of acquired sensorineural hearing loss. Cisplatin and aminoglycoside antibiotics have been known to cause ototoxicity, and excessive accumulation of intracellular reactive oxygen species (ROS) are suggested as the common major pathology of cisplatin- and aminoglycoside antibiotics-induced ototoxicity. Fursultiamine, also called thiamine tetrahydrofurfuryl disulfide, is a thiamine disulfide derivative that may have antioxidant effects. To evaluate whether fursultiamine can prevent cisplatin- and kanamycin-induced ototoxicity, we investigated their preventive potential using mouse cochlear explant culture system. Immunofluorescence staining of mouse cochlear hair cells showed that fursultiamine pretreatment reduced cisplatin- and kanamycin-induced damage to both inner and outer hair cells. Fursultiamine attenuated mitochondrial ROS accumulation as evidenced by MitoSOX Red staining and restored mitochondrial membrane potential in a JC-1 assay. In addition, fursultiamine pretreatment reduced active caspase-3 and TUNEL signals after cisplatin or kanamycin treatment, indicating that fursultiamine decreased apoptotic hair cell death. This study is the first to show a protective effect of fursultiamine against cisplatin- and aminoglycoside antibiotics-induced ototoxicity. Our results suggest that fursultiamine could act as an antioxidant and anti-apoptotic agent against mitochondrial oxidative stress.in cochlear hair cells.

Targeting ROS-AMPK pathway by multiaction Platinum(IV) prodrugs containing hypolipidemic drug bezafibrate

Alterations in lipid metabolism, commonly disregarded in the past, have been accepted as a hallmark for cancer. Exploring cancer therapeutics that interrupt the lipid metabolic pathways by monotherapy or combination with conventional chemotherapy or immunotherapy is of great importance. Here we modified cisplatin with an FDA-approved hypolipidemic drug, bezafibrate (BEZ), via the well-established Pt(IV) strategy, affording two multi-functional Pt(IV) anticancer agents cis,cis,trans-[Pt(NH₃)₂Cl₂(BEZ)(OH)] (CB) and cis,cis,trans-[Pt(NH₃)₂Cl₂(BEZ)₂] (CP) (BEZ = bezafibrate). The Pt(IV) prodrug CB exhibited an enhanced anticancer activity up to 187-fold greater than the clinical anticancer drug cisplatin. Both CB and CP had less toxicity to normal cells, showing higher efficacies and superior therapeutic indexes than cisplatin. Mechanism studies revealed that the bezafibrate-conjugated Pt(IV) complex CB, as a representative, could massively accumulate in A549 cells and genomic DNA, induce DNA damage, elevate intracellular ROS levels, perturb mitochondrial transmembrane potentials, activate the cellular metabolic sensor AMPK, and result in profound proliferation inhibition and apoptosis. Further cellular data also provided evidence that phosphorylation of AMPK, as a metabolic sensor, could suppress the downstream HMGB1, NF-κB, and VEGFA, which may contribute to the inhibition of angiogenesis and metastasis. Our study suggests that the antitumor action of CB and CP mechanistically distinct from the conventional platinum drugs and that functionalizing platinum-based agents with lipid-modulating agents may represent a novel practical strategy for cancer treatment.

Silicane Derivative Increases Doxorubicin Efficacy in an Ovarian Carcinoma Mouse Model: Fighting Drug Resistance

The development of cancer resistance continues to represent a bottleneck of cancer therapy. It is one of the leading factors preventing drugs to exhibit their full therapeutic potential. Consequently, it reduces the efficacy of anticancer therapy and causes the survival rate of therapy-resistant patients to be far from satisfactory. Here, an emerging strategy for overcoming drug resistance is proposed employing a novel two-dimensional (2D) nanomaterial polysiloxane (PSX). We have reported on the synthesis of PSX nanosheets (PSX NSs) and proved that they have favorable properties for biomedical applications. PSX NSs evinced unprecedented cytocompatibility up to the concentration of 300 μg/mL, while inducing very low level of red blood cell hemolysis and were found to be highly effective for anticancer drug binding. PSX NSs enhanced the efficacy of the anticancer drug doxorubicin (DOX) by around 27.8-43.4% on average and, interestingly, were found to be especially effective in the therapy of drug-resistant tumors, improving the effectiveness of up to 52%. Fluorescence microscopy revealed improved retention of DOX within the drug-resistant cells when bound on PSX NSs. DOX bound on the surface of PSX NSs, i.e., PSX@DOX, improved, in general, the DOX cytotoxicity in vitro. More importantly, PSX@DOX reduced the growth of DOX-resistant tumors in vivo with 3.5 times better average efficiency than the free drug. Altogether, this paper represents an introduction of a new 2D nanomaterial derived from silicane and pioneers its biomedical application. As advances in the field of material synthesis are rapidly progressing, novel 2D nanomaterials with improved properties are being synthesized and await thorough exploration. Our findings further provide a better understanding of the mechanisms involved in the cancer resistance and can promote the development of a precise cancer therapy.

Unearthing the Janus-face cholesterogenesis pathways in cancer

Cholesterol biosynthesis, primarily associated with eukaryotes, occurs as an essential component of human metabolism with biosynthetic deregulation a factor in cancer viability. The segment that partitions between squalene and the C₂₇-end cholesterol yields the main cholesterogenesis branch subdivided into the Bloch and Kandutsch-Russell pathways. Their importance in cell viability, in normal growth and development originates primarily from the amphipathic property and shape of the cholesterol molecule which makes it suitable as a membrane insert. Cholesterol can also convert to variant oxygenated product metabolites of distinct function producing a complex interplay between cholesterol synthesis and overall steroidogenesis. In this review, we disassociate the two sides of cholesterogenesisis affecting the type and amounts of systemic sterols-one which is beneficial to human welfare while the other dysfunctional leading to misery and disease that could result in premature death. Our focus here is first to examine the cholesterol biosynthetic genes, enzymes, and order of biosynthetic intermediates in human cholesterogenesis pathways, then compare the effect of proximal and distal inhibitors of cholesterol biosynthesis against normal and cancer cell growth and metabolism. Collectively, the inhibitor studies of druggable enzymes and specific biosynthetic steps, suggest a potential role of disrupted cholesterol biosynthesis, in coordination with imported cholesterol, as a factor in cancer development and as discussed some of these inhibitors have chemotherapeutic implications.

Statins as adjuvants in the treatment of ovarian cancer: Controversy and misunderstanding

Ovarian cancer is frequently detected in advanced stages when the chances of survival are very low. Although chemotherapy is the treatment of choice, it is often rapidly compromised by the development of chemoresistance in patients. There are few pharmacological alternatives for managing chemoresistant ovarian cancer and statins have been suggested as an alternative, but their use is considered controversial. We present an overview of the most relevant epidemiological, in vitro and in vivo studies on the effects of statins in mono- or polytherapy for ovarian cancer. We conclude that the negative or inconclusive results of some epidemiological studies on statin-based cancer treatment are probably due, in large part, to the low doses given to patients, equivalent to those prescribed for hypercholesterolemia. Higher concentrations are well tolerated in animal models and by most patients in clinical trials. Future research is necessary to explore this possibility.

Pleiotropic effects of statins: A focus on cancer

The statin drugs ('statins') potently inhibit hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase by competitively blocking the active site of the enzyme. Statins decrease de novo cholesterol biosynthesis and thereby reduce plasma cholesterol levels. Statins exhibit "pleiotropic" properties that are independent of their lipid-lowering effects. For example, preclinical evidence suggests that statins inhibit tumor growth and induce apoptosis in specific cancer cell types. Furthermore, statins show chemo-sensitizing effects by impairing Ras family GTPase signaling. However, whether statins have clinically meaningful anti-cancer effects remains an area of active investigation. Both preclinical and clinical studies on the potential mechanisms of action of statins in several cancers have been reviewed in the literature. Considering the contradictory data on their efficacy, we present an up-to-date summary of the pleiotropic effects of statins in cancer therapy and review their impact on different malignancies. We also discuss the synergistic anti-cancer effects of statins when combined with other more conventional anti-cancer drugs to highlight areas of potential therapeutic development.

Recycling the Purpose of Old Drugs to Treat Ovarian Cancer

The main challenge in ovarian cancer treatment is the management of recurrences. Facing this scenario, therapy selection is based on multiple factors to define the best treatment sequence. Target therapies, such as bevacizumab and polymerase (PARP) inhibitors, improved patient survival. However, despite their achievements, ovarian cancer survival remains poor; these therapeutic options are highly costly and can be associated with potential side effects. Recently, it has been shown that the combination of repurposed, conventional, chemotherapeutic drugs could be an alternative, presenting good patient outcomes with few side effects and low costs for healthcare institutions. The main aim of this review is to strengthen the importance of repurposed drugs as therapeutic alternatives, and to propose an in vitro model to assess the therapeutic value. Herein, we compiled the current knowledge on the most promising non-oncological drugs for ovarian cancer treatment, focusing on statins, metformin, bisphosphonates, ivermectin, itraconazole, and ritonavir. We discuss the primary drug use, anticancer mechanisms, and applicability in ovarian cancer. Finally, we propose the use of these therapies to perform drug efficacy tests in ovarian cancer ex vivo cultures. This personalized testing approach could be crucial to validate the existing evidences supporting the use of repurposed drugs for ovarian cancer treatment.

Simvastatin is a potential candidate drug in ovarian clear cell carcinomas

Ovarian clear cell carcinomas (OCCC) constitute a rare subtype of epithelial ovarian cancer, lacking efficient treatment options. Based on previous studies, we assessed the anti-proliferative effect of simvastatin, a Rho GTPase interfering drug, in three OCCC cell lines: JHOC-5, OVMANA and TOV-21G, and one high-grade serous ovarian cancer (HGSOC) cell line, Caov3. We used the Rho GTPase interfering drug CID-1067700 as a control. All OCCC cell lines were more sensitive to single-agent simvastatin than the HGSOC cells, while all cell lines were less sensitive to CID-1067700 than to simvastatin. Combinations of carboplatin and simvastatin were generally antagonistic. Most treatments inhibited migration, while only simvastatin and CID-1067700 also disrupted actin organization in the OCCC cell lines. All treatments induced a G1 arrest in JHOC-5 and TOV-21G cells. Treatments with simvastatin consistently reduced c-Myc protein expression in all OCCC cell lines and displayed evidence of causing both caspase-mediated apoptotic cell death and autophagic response in a cell line dependent manner. Differences between cell lines in response to the treatments were observed and such differences, including e. g. prior treatment, should be investigated further. Conclusively, simvastatin efficiently controlled OCCC proliferation and migration, thus showing potential as a candidate drug for the treatment of OCCC.

Lipid composition of the cancer cell membrane

Cancer cell possesses numerous adaptations to resist the immune system response and chemotherapy. One of the most significant properties of the neoplastic cells is the altered lipid metabolism, and consequently, the abnormal cell membrane composition. Like in the case of phosphatidylcholine, these changes result in the modulation of certain enzymes and accumulation of energetic material, which could be used for a higher proliferation rate. The changes are so prominent, that some lipids, such as phosphatidylserines, could even be considered as the cancer biomarkers. Additionally, some changes of biophysical properties of cell membranes lead to the higher resistance to chemotherapy, and finally to the disturbances in signalling pathways. Namely, the increased levels of certain lipids, like for instance phosphatidylserine, lead to the attenuation of the immune system response. Also, changes in lipid saturation prevent the cells from demanding conditions of the microenvironment. Particularly interesting is the significance of cell membrane cholesterol content in the modulation of metastasis. This review paper discusses the roles of each lipid type in cancer physiology. The review combined theoretical data with clinical studies to show novel therapeutic options concerning the modulation of cell membranes in oncology.

Statins as Anticancer Agents in the Era of Precision Medicine

Statins are widely prescribed cholesterol-lowering drugs that inhibit HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate metabolic pathway. Multiple lines of evidence indicate that certain cancers depend on the mevalonate pathway for growth and survival, and, therefore, are vulnerable to statin therapy. However, these immediately available, well-tolerated, and inexpensive drugs have yet to be successfully repurposed and integrated into cancer patient care. In this review, we highlight recent advances and outline important considerations for advancing statins to clinical trials in oncology.

Targeting SREBP-2-Regulated Mevalonate Metabolism for Cancer Therapy

Recently, targeting metabolic reprogramming has emerged as a potential therapeutic approach for fighting cancer. Sterol regulatory element binding protein-2 (SREBP-2), a basic helix-loop-helix leucine zipper transcription factor, mainly regulates genes involved in cholesterol biosynthesis and homeostasis. SREBP-2 binds to the sterol regulatory elements (SREs) in the promoters of its target genes and activates the transcription of mevalonate pathway genes, such as HMG-CoA reductase (HMGCR), mevalonate kinase and other key enzymes. In this review, we first summarized the structure of SREBP-2 and its activation and regulation by multiple signaling pathways. We then found that SREBP-2 and its regulated enzymes, including HMGCR, FPPS, SQS, and DHCR4 from the mevalonate pathway, participate in the progression of various cancers, including prostate, breast, lung, and hepatocellular cancer, as potential targets. Importantly, preclinical and clinical research demonstrated that fatostatin, statins, and N-BPs targeting SREBP-2, HMGCR, and FPPS, respectively, alone or in combination with other drugs, have been used for the treatment of different cancers. This review summarizes new insights into the critical role of the SREBP-2-regulated mevalonate pathway for cancer and its potential for targeted cancer therapy.

The mevalonate pathway is an actionable vulnerability of t(4;14)-positive multiple myeloma

Multiple myeloma (MM) is a plasma cell malignancy that is often driven by chromosomal translocations. In particular, patients with t(4;14)-positive disease have worse prognosis compared to other MM subtypes. Herein, we demonstrated that t(4;14)-positive cells are highly dependent on the mevalonate (MVA) pathway for survival. Moreover, we showed that this metabolic vulnerability is immediately actionable, as inhibiting the MVA pathway with a statin preferentially induced apoptosis in t(4;14)-positive cells. In response to statin treatment, t(4;14)-positive cells activated the integrated stress response (ISR), which was augmented by co-treatment with bortezomib, a proteasome inhibitor. We identified that t(4;14)-positive cells depend on the MVA pathway for the synthesis of geranylgeranyl pyrophosphate (GGPP), as exogenous GGPP fully rescued statin-induced ISR activation and apoptosis. Inhibiting protein geranylgeranylation similarly induced the ISR in t(4;14)-positive cells, suggesting that this subtype of MM depends on GGPP, at least in part, for protein geranylgeranylation. Notably, fluvastatin treatment synergized with bortezomib to induce apoptosis in t(4;14)-positive cells and potentiated the anti-tumor activity of bortezomib in vivo. Our data implicate the t(4;14) translocation as a biomarker of statin sensitivity and warrant further clinical evaluation of a statin in combination with bortezomib for the treatment of t(4;14)-positive disease.

An Overview of Candidate Therapeutic Target Genes in Ovarian Cancer

Ovarian cancer (OC) shows the highest mortality rate among gynecological malignancies and, because of the absence of specific symptoms, it is frequently diagnosed at an advanced stage, mainly due to the lack of specific and early biomarkers, such as those based on cancer molecular signature identification. Indeed, although significant progress has been made toward improving the clinical outcome of other cancers, rates of mortality for OC are essentially unchanged since 1980, suggesting the need of new approaches to identify and characterize the molecular mechanisms underlying pathogenesis and progression of these malignancies. In addition, due to the low response rate and the high frequency of resistance to current treatments, emerging therapeutic strategies against OC focus on targeting single factors and pathways specifically involved in tumor growth and metastasis. To date, loss-of-function screenings are extensively applied to identify key drug targets in cancer, seeking for more effective, disease-tailored treatments to overcome lack of response or resistance to current therapies. We review here the information relative to essential genes and functional pathways recently discovered in OC, often strictly interconnected with each other and representing promising biomarkers and molecular targets to treat these malignancies.

Targeting on glycosylation of mutant FLT3 in acute myeloid leukemia

Objective: To summarize the abnormal location of FLT3 caused by different glycosylation status which further leads to the distinguishing signaling pathways and discuss targeting on FLT3 glycosylation by drugs reported in recent literatures. Methods: We review FLT3 glycosylation in endoplasmic reticulum. The abnormal signal of mutant FLT3 with different glycosylation status is discussed. We also address potential FLT3 glycosylation-targeting strategies for the treatment. Results: Inhibition of FLT3 mutant cells by drugs reported in recent literatures involves the influence of glycosylation of FLT3: 2-deoxy-D-glucose, Tunicamycin and Fluvastatin are reported to inhibit N-glycosylation of FLT3; Pim-1 inhibitors are proved to block the inhibition of Pim-1 on FLT3 Oglycosylation; HSP90 inhibitors and Tyrosine Kinase Inhibitors are shown to increase fully glycosylated form of FLT3. Discussion: The FMS-like tyrosine kinase 3 (FLT3) gene expressed only in CD34+ progenitor cells in bone marrow is located on chromosome 13q12 encoding FLT3 protein. FLT3 is initially synthesized as a 110 KD protein, which glycosylated in the endoplasmic reticulum to a 130 KD immature protein rich in mannose, and further processed into a mature 160 KD protein in the Golgi apparatus, which could be transferred to the cell surface. Therapy targeting on FLT3 glycosylation is a promising direction for AML treatment. Conclusions: The abnormal location of FLT3 caused by different glycosylation status leads to the distinguishing signaling pathways. Targeting on FLT3 glycosylation may provide a new perspective for therapeutic strategies. Abbreviations: ABCG2: ATP-binding cassette transporter breast cancer resistance protein; ATF: activating transcription factor; AML: acute myeloid leukemia; CHOP: CCAAT-enhancer-binding protein homologous protein; 2-DG: 2-deoxy-D-glucose; EFS: event free survival; EPO: erythropoietin; EPOR: erythropoietin receptor; ERS: endoplasmic reticulum stress; FLT3: FMS-like tyrosine kinase 3; GPI: glycosylphosphatidylinositol; HSP: heat shock protein; ITD: internal tandem duplication; IRE1a: inositol-requiring enzyme 1 alpha; JNK: c-Jun N-terminal kinase; JMD: juxtamembrane domain; JAK: janus kinase; MAPK/ERK: mitogen activated protein kinase/extracellular signal-regulated protein kinase; OS: overall survival; PI3K/AKT: phosphatidylinositide 3-kinases/protein kinase B; PERK: RNA-activated protein kinase-like endoplasmic reticulum kinase; Pgp: P-glycoprotein; PTX3: human pentraxin-3; STAT: signal transducer and activator of transcriptions; TKD: tyrosine-kinase domain; TKI: tyrosine kinase inhibitor; TM: Tunicamycin; UPR: unfolded protein reaction.

Associations between metabolic syndrome and gynecologic cancer

Metabolic syndrome (MetS) is a group of risk factors that causes cardiovascular and diabetic morbidity and mortality, which is diagnosed by central obesity, dyslipidemia, hyperglycemia, and hypertension. Increasing epidemiological data and experimental results indicate that the presence of MetS increases the incidence of common malignancies and related mortality. Epidemiological studies have previously reported an association of endometrial cancer occurrence with MetS. Aromatization of androstenedione to estrogen, insulin resistance, and diabetes can cause increased levels of free estrogen, and the detrimental effect of elevated estrogen as a carcinogen is well studied in endometrial cancer. Medications used to manage MetS such as metformin and statins are suggested to reduce endometrial cancer risk and improve survival. Some large population-based epidemiological studies have suggested that the MetS is related to an increased risk of cervical carcinoma. MetS may contribute to viral-host interactions, which lead to persistent human papilloma virus (HPV) infection, although limited epidemiological data are available. Specific effects of obesity and diabetes on the occurrence of ovarian cancer have been suggested. However, the direct correlation between MetS and ovarian cancer is still lacking. Previous retrospective studies reported that the use of metformin, statins, and beta-blockers could be associated with cancer prevention or better prognosis. Proper diagnosis and management of the MetS should be a part of the strategies undertaken to prevent and treat gynecologic cancer. So far, only limited data is available on this subject, and further clinical and fundamental research is required to further clarify the effect of these therapies on gynecologic cancer treatment.

A pilot window-of-opportunity study of preoperative fluvastatin in localized prostate cancer

Background

Statins inhibit HMG-CoA reductase, the rate-limiting enzyme of the mevalonate pathway. Epidemiological and pre-clinical evidence support an association between statin use and delayed prostate cancer (PCa) progression. Here, we evaluated the effects of neoadjuvant fluvastatin treatment on markers of cell proliferation and apoptosis in men with localized PCa.

Methods

Thirty-three men were treated daily with 80 mg fluvastatin for 4–12 weeks in a single-arm window-of-opportunity study between diagnosis of localized PCa and radical prostatectomy (RP) (ClinicalTrials.gov: NCT01992042). Percent Ki67 and cleaved Caspase-3 (CC3)-positive cells in tumor tissues were evaluated in 23 patients by immunohistochemistry before and after treatment. Serum and intraprostatic fluvastatin concentrations were quantified by liquid chromatography-mass spectrometry.

Results

Baseline characteristics included a median prostate-specific antigen (PSA) level of 6.48 ng/mL (IQR: 4.21–10.33). The median duration of fluvastatin treatment was 49 days (range: 27–102). Median serum low-density lipoprotein levels decreased by 35% after treatment, indicating patient compliance. Median PSA decreased by 12%, but this was not statistically significant in our small cohort. The mean fluvastatin concentration measured in the serum was 0.2 μM (range: 0.0–1.1 μM), and in prostatic tissue was 8.5 nM (range: 0.0–77.0 nM). At these concentrations, fluvastatin induced PCa cell death in vitro in a dose- and time-dependent manner. In patients, fluvastatin treatment did not significantly alter intratumoral Ki67 positivity; however, a median 2.7-fold increase in CC3 positivity (95% CI: 1.9–5.0, p = 0.007) was observed in post-fluvastatin RP tissues compared with matched pre-treatment biopsy controls. In a subset analysis, this increase in CC3 was more pronounced in men on fluvastatin for >50 days.

Conclusions

Fluvastatin prior to RP achieves measurable drug concentrations in prostatic tissue and is associated with promising effects on tumor cell apoptosis. These data warrant further investigation into the anti-neoplastic effects of statins in prostate tissue.

Association Between Genetically Proxied Inhibition of HMG-CoA Reductase and Epithelial Ovarian Cancer

Importance

Preclinical and epidemiological studies indicate a potential chemopreventive role of statins in epithelial ovarian cancer risk.

Objective

To evaluate the association of genetically proxied inhibition of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (ie, genetic variants related to lower function of HMG-CoA reductase, target of statins) with epithelial ovarian cancer among the general population and in BRCA1/2 mutation carriers.

Design, Setting, and Participants

Single-nucleotide polymorphisms (SNPs) in HMGCR, NPC1L1, and PCSK9 associated with low-density lipoprotein (LDL) cholesterol in a genome-wide association study (GWAS) meta-analysis (N ≤196 475) were used to proxy therapeutic inhibition of HMG-CoA reductase, Niemann-Pick C1-Like 1 (NPC1L1) and proprotein convertase subtilisin/kexin type 9 (PCSK9), respectively. Summary statistics were obtained for these SNPs from a GWAS meta-analysis of case-control analyses of invasive epithelial ovarian cancer in the Ovarian Cancer Association Consortium (OCAC; N = 63 347) and from a GWAS meta-analysis of retrospective cohort analyses of epithelial ovarian cancer among BRCA1/2 mutation carriers in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA; N = 31 448). Across the 2 consortia, participants were enrolled between 1973 and 2014 and followed up through 2015. OCAC participants came from 14 countries and CIMBA participants came from 25 countries. SNPs were combined into multi-allelic models and mendelian randomization estimates representing lifelong inhibition of targets were generated using inverse-variance weighted random-effects models.

Exposures

Primary exposure was genetically proxied inhibition of HMG-CoA reductase and secondary exposures were genetically proxied inhibition of NPC1L1 and PCSK9 and genetically proxied circulating LDL cholesterol levels.

Main Outcomes and Measures

Overall and histotype-specific invasive epithelial ovarian cancer (general population) and epithelial ovarian cancer (BRCA1/2 mutation carriers), measured as ovarian cancer odds (general population) and hazard ratio (BRCA1/2 mutation carriers).

Results

The OCAC sample included 22 406 women with invasive epithelial ovarian cancer and 40 941 control individuals and the CIMBA sample included 3887 women with epithelial ovarian cancer and 27 561 control individuals. Median ages for the cohorts ranged from 41.5 to 59.0 years and all participants were of European ancestry. In the primary analysis, genetically proxied HMG-CoA reductase inhibition equivalent to a 1-mmol/L (38.7-mg/dL) reduction in LDL cholesterol was associated with lower odds of epithelial ovarian cancer (odds ratio [OR], 0.60 [95% CI, 0.43-0.83]; P = .002). In BRCA1/2 mutation carriers, genetically proxied HMG-CoA reductase inhibition was associated with lower ovarian cancer risk (hazard ratio, 0.69 [95% CI, 0.51-0.93]; P = .01). In secondary analyses, there were no significant associations of genetically proxied inhibition of NPC1L1 (OR, 0.97 [95% CI, 0.53-1.75]; P = .91), PCSK9 (OR, 0.98 [95% CI, 0.85-1.13]; P = .80), or circulating LDL cholesterol (OR, 0.98 [95% CI, 0.91-1.05]; P = .55) with epithelial ovarian cancer.

Conclusions and Relevance

Genetically proxied inhibition of HMG-CoA reductase was significantly associated with lower odds of epithelial ovarian cancer. However, these findings do not indicate risk reduction from medications that inhibit HMG-CoA reductase; further research is needed to understand whether there is a similar association with such medications.

Cholesterol and beyond - The role of the mevalonate pathway in cancer biology

Cancer is a multifaceted global disease. Transformation of a normal to a malignant cell takes several steps, including somatic mutations, epigenetic alterations, metabolic reprogramming and loss of cell growth control. Recently, the mevalonate pathway has emerged as a crucial regulator of tumor biology and a potential therapeutic target. This pathway controls cholesterol production and posttranslational modifications of Rho-GTPases, both of which are linked to several key steps of tumor progression. Inhibitors of the mevalonate pathway induce pleiotropic antitumor-effects in several human malignancies, identifying the pathway as an attractive candidate for novel therapies. In this review, we will provide an overview about the role and regulation of the mevalonate pathway in certain aspects of cancer initiation and progression and its potential for therapeutic intervention in oncology.

SIK2 enhances synthesis of fatty acid and cholesterol in ovarian cancer cells and tumor growth through PI3K/Akt signaling pathway

Salt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

Encapsulation of Lovastatin in Zein Nanoparticles Exhibits Enhanced Apoptotic Activity in HepG2 Cells

Research on statins highlights their potent cytotoxicity against cancer cells and their potential for cancer prevention. The aim of the current study was to examine whether loading lovastatin (LVS) in zein (ZN) nanoparticles (NPs) would potentiate the anti-proliferative effects of LVS and enhance its proliferation-inhibiting activity in HepG2 cells. LVS-ZN NPs were prepared and showed excellent characteristics, with respect to their particle size, zeta potential, diffusion, and entrapment efficiency. In addition, they showed the most potent anti-proliferative activity against HepG2 cells. ZN alone showed an observable anti-proliferative that was significantly higher than that of raw LVS. Furthermore, LVS uptake by HepG2 cells was greatly enhanced by the formulation in ZN. A cell cycle analysis indicated that LVS induced a significant cell accumulation in the G2/M and pre-G phases. In this regard, the LVS-ZN NPs exhibited the highest potency. The accumulation in the pre-G phase indicated an enhanced pro-apoptotic activity of the prepared formula. The cells incubated with the LVS-ZN NPs showed the highest percentage of cells with annexin-V positive staining. In addition, the same incubations showed the highest content of caspase-3 enzyme in comparison to raw LVS or ZN. Thus, the loading of LVS in ZN nanoparticles enhances its anti-proliferative activity against HepG2 cells, which is attributed, at least partly, to the enhanced cellular uptake and the induction of apoptosis.

The ABC subfamily A transporters: Multifaceted players with incipient potentialities in cancer

Overexpression of ATP-binding cassette (ABC) transporters is a cause of drug resistance in a plethora of tumors. More recent evidence indicates additional contribution of these transporters to other processes, such as tumor cell dissemination and metastasis, thereby extending their possible roles in tumor progression. While the role of some ABC transporters, such as ABCB1, ABCC1 and ABCG2, in multidrug resistance is well documented, the mechanisms by which ABC transporters affect the proliferation, differentiation, migration and invasion of cancer cells are still poorly defined and are frequently controversial. This review, summarizes recent advances that highlight the role of subfamily A members in cancer. Emerging evidence highlights the potential value of ABCA members as biomarkers of risk and response in different tumors, but information is disperse and very little is known about their possible mechanisms of action. The only clear evidence is that ABCA members are involved in lipid metabolism and homeostasis. In particular, the relationship between ABCA1 and cholesterol is becoming evident in different fields of biology, including cancer. In parallel, emerging findings indicate that cholesterol, the main component of cell membranes, can influence many physiological and pathological processes, including cell migration, cancer progression and metastasis. This review aims to link the dispersed knowledge regarding the relationship of ABCA members with lipid metabolism and cancer in an effort to stimulate and guide readers to areas that the writers consider to have significant impact and relevant potentialities.