Cholesterol depletion by methyl-β-cyclodextrin augments tamoxifen induced cell death by enhancing its uptake in melanoma

Circular RNA circ_HN1 facilitates gastric cancer progression through modulation of the miR-302b-3p/ROCK2 axis

Gastric cancer (GC) is a malignant tumor with high morbidity and mortality in the world. Circular RNA hsa_circHN1_005 (circ_HN1), also termed as hsa_circ_0045602, is reported as an oncogene in GC. However, the molecular mechanism of circ_HN1 in GC development has not been fully explored. Here, we surveyed the regulatory mechanism of circ_HN1 in GC progression. The levels of circ_HN1, miR-302b-3p, and rho-associated coiled-coil containing protein kinase 2 (ROCK2) mRNA were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, apoptosis, colony formation, cell cycle progresion, migration, and invasion were determined by using cell counting, flow cytometry, colony formation, or transwell assays. Protein levels were detected with Western blotting. The relationship between circ_HN1 or ROCK2 and miR-302b-3p was verified via dual luciferase reporter or RNA immunoprecipitation (RIP) assays. The role of circ_HN1 in vivo was confirmed by xenograft assay. We observed that circ_HN1 and ROCK2 were upregulated while miR-302b-3p was downregulated in GC tissues and cells. Circ_HN1 silencing slowed tumor growth in vivo and impeded cell proliferation migration, invasion, and facilitated cell apoptosis in GC cells in vitro. Circ_HN1 sponged miR-302b-3p to regulate ROCK2 expression. MiR-302b-3p inhibitor reversed circ_HN1 silencing-mediated influence on the malignant behaviors of GC cells. Furthermore, ROCK2 overexpression restored miR-302b-3p mimic-mediated impacts on cell malignant behaviors in GC cells. In conclusion, circ_HN1 exerted an oncogenic role in GC through upregulating ROCK2 via sponging miR-302b-3p, offering evidence that circ_HN1 is a potential target for GC therapy.

LncRNA SNHG16 as a potential biomarker and therapeutic target in human cancers

Long non-coding RNAs (lncRNAs) represent an important class of RNAs comprising more than 200 nucleotides, which are produced by RNA polymerase II. Although lacking an open reading framework and protein-encoding activity, lncRNAs can mediate endogenous gene expression by serving as chromatin remodeler, transcriptional or post-transcriptional modulator, and splicing regulator during gene modification. In recent years, increasing evidence shows the significance of lncRNAs in many malignancies, with vital roles in tumorigenesis and cancer progression. Moreover, lncRNAs were also considered potential diagnostic and prognostic markers in cancer. The lncRNA small nuclear RNA host gene 16 (SNHG16), found on chromosome 17q25.1, represents a novel tumor-associated lncRNA. SNHG16 was recently found to exhibit dysregulated expression in a variety of malignancies. There are growing evidence of SNHG16's involvement in characteristics of cancer, including proliferation, apoptosis, together with its involvement in chemoresistance. In addition, SNHG16 has been described as a promising diagnostic and prognostic biomarker in cancer patients. The current review briefly summarizes recently reported findings about SNHG16 and discuss its expression, roles, mechanisms, and diagnostic and prognostic values in human cancers.

An orally available hypoglycaemic peptide taken up by caveolae transcytosis displays improved hypoglycaemic effects and body weight control in db/db mice

BACKGROUND AND PURPOSE

Type 2 diabetes is one of the most severe chronic diseases and is an increasingly important public health problem worldwide. Several agonists of the glucagon-like peptide-1 (GLP-1) receptor have been developed to treat Type 2 diabetes but most of them are administered by injection. This mode of administration seriously reduces patient compliance and increases the risk of infection. Here, we describe the actions of a novel, orally available, GLP-1 receptor agonist - oral hypoglycaemic peptide 2 (OHP2) - derived from exendin-4 by replacing amino acids. We have also investigated its pharmacokinetic profiles, therapeutic effects and absorption mechanism.

EXPERIMENTAL APPROACH

Healthy Wistar rats were used for pharmacokinetic analyses. In diabetic db/db mice. OHP2 was given for 8 weeks to evaluate its effects on hyperglycaemia, dyslipidaemia, basal metabolism and tissue injury. Possible endocytosis and transcytosis mechanisms of OHP2 uptake were explored in Caco-2 cell monolayers.

KEY RESULTS

In rats, the absolute bioavailability of orally administered OHP2 was 20-fold greater than that of orally administered exendin-4. In db/db mice, OHP2 dose-dependently exhibits good potential in glucose-lowering and weight loss after oral administration. OHP2 also alleviated hyperlipidaemia, ameliorated energy metabolism and promoted tissue repair in diabetic mice. Furthermore, uptake of OHP2 by Caco-2 cells was dependent on caveolae-mediated transcytosis rather than endocytosis mediated by GLP-1 receptors.

CONCLUSIONS AND IMPLICATIONS

OHP2 is a potential, orally bioavailable, candidate drug for the treatment of Type 2 diabetes. Its transcytosis mechanism of uptake could help in the development of absorption enhancers of OHP2.

High expression of miR-135b predicts malignant transformation and poor prognosis of gastric cancer

AIMS

MiR-135b is a downstream effector of oncogenic signaling pathways. This study aimed to reveal the underlying regulation and significance of miR-135b in gastric cancer.

MATERIALS AND METHODS

The influence of Wnt and PI3K/AKT signaling pathways on the transcriptional activation of the miR-135b promoter was determined by dual-luciferase reporter assays. In vitro experiments, including the cell counting kit-8 (CCK8) assay, 5-ethynyl-2'-deoxyuridine (EdU) staining, flow cytometry analysis and malignant phenotype profiles, were conducted to determine the oncogenic role of miR-135b in gastric cancer. To analyze the clinical significance of miR-135b in gastric cancer, the expression profile of miR-135b in tissue specimens and plasma was examined by quantitative real-time PCR (qRT-PCR).

KEY FINDINGS

Oncogenic signaling pathways represented by Wnt and PI3K/AKT promoted the transcriptional activation of the miR-135b promoter in gastric cancer. Downregulation of miR-135b inhibited proliferation, promoted apoptosis, and suppressed the migratory, invasive, and adherent abilities as well as the cancer stem cell phenotype of gastric cancer cells. High expression of miR-135b in gastric cancer tissues was tightly associated with poor prognosis and malignant transformation represented by metastasis of gastric cancer. The miR-135b level in the plasma of gastric cancer patients was significantly higher than that in healthy individuals.

SIGNIFICANCE

MiR-135b is a potential downstream effector of the Wnt and PI3K/AKT signaling pathways in gastric cancer. High expression of miR-135b may predict malignant transformation and poor prognosis of gastric cancer. This study reveals the potential role of miR-135b as a target for the early diagnosis and therapy of gastric cancer.

Long Noncoding RNA CCAT1 Functions as a Competing Endogenous RNA to Upregulate ITGA9 by Sponging MiR-296-3p in Melanoma

Background

Melanoma is aggressive and lethal melanocytic neoplasm, and its incidence has increased worldwide in recent decades. Accumulating evidence has showed that various long noncoding RNAs (lncRNAs) participated in occurrence of malignant tumors, including melanoma. The present study was designed to investigate function of lncRNA colon cancer-associated transcript-1 (CCAT1) in melanoma.

Methods

The expression levels of CCAT1, miR-296-3p and Integrin alpha9 (ITGA9) in melanoma tissues or cells were measured using real-time quantitative polymerase chain reaction (RT-qPCR). The concentrations of glucose and lactate were measured for assessing glycolysis of melanoma cells. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), flow cytometry, and transwell assays were conducted to assess proliferation, apoptosis, and migration of melanoma cells. Western blot assay was performed to measure the protein expression of ITGA9, hexokinase 2 (HK2), and epithelial–mesenchymal transition (EMT)-related proteins in melanoma tissues or cells. The relationship among CCAT1, miR-296-3p, and ITGA9 was predicted and confirmed by bioinformatics analysis, dual-luciferase reporter, and RNA immunoprecipitation (RIP) assay, respectively. A xenograft experiment was established to assess the effect of CCAT1 knockdown in vivo.

Results

CCAT1 was effectively increased in melanoma tissues and cells compared with matched controls, and deficiency of CCAT1 impeded cell glycolysis, proliferation, migration while induced apoptosis, which were abrogated by knockdown of miR-296-3p in melanoma cells. In addition, our findings revealed that ITGA9 overexpression abolished miR-296-3p overexpression-induced effects on melanoma cells. Importantly, CCAT1 regulated ITGA9 expression by sponging miR-296-3p. The results of xenograft experiment suggested that CCAT1 silencing inhibited melanoma cell growth in vivo.

Conclusion

LncRNA CCAT1 promoted ITGA9 expression by sponging miR-296-3p in melanoma.

OSskcm: an online survival analysis webserver for skin cutaneous melanoma based on 1085 transcriptomic profiles

Background

Cutaneous melanoma is one of the most aggressive and lethal skin cancers. It is greatly important to identify prognostic biomarkers to guide the clinical management. However, it is technically challenging for untrained researchers to process high dimensional profiling data and identify potential prognostic genes in profiling datasets.

Methods

In this study, we developed a webserver to analyze the prognostic values of genes in cutaneous melanoma using data from TCGA and GEO databases. The webserver is named Online consensus Survival webserver for Skin Cutaneous Melanoma (OSskcm) which includes 1085 clinical melanoma samples. The OSskcm is hosted in a windows tomcat server. Server-side scripts were developed in Java script. The database system is managed by a SQL Server, which integrates gene expression data and clinical data. The Kaplan–Meier (KM) survival curves, Hazard ratio (HR) and 95% confidence interval (95%CI) were calculated in a univariate Cox regression analysis.

Results

In OSskcm, by inputting official gene symbol and selecting proper options, users could obtain KM survival plot with log-rank P value and HR on the output web page. In addition, clinical characters including race, stage, gender, age and type of therapy could also be included in the prognosis analysis as confounding factors to constrain the analysis in a subgroup of melanoma patients.

Conclusion

The OSskcm is highly valuable for biologists and clinicians to perform the assessment and validation of new or interested prognostic biomarkers for melanoma. OSskcm can be accessed online at: http://bioinfo.henu.edu.cn/Melanoma/MelanomaList.jsp.

Long Noncoding RNA LINC00173 Promotes the Malignancy of Melanoma by Promoting the Expression of IRS4 Through Competitive Binding to microRNA-493

Purpose

Long intergenic non-protein-coding RNA 173 (LINC00173) plays crucial roles in lung cancer. However, the expression and biological functions of LINC00173 in melanoma have not yet been investigated. In this study, we aimed to characterize the involvement of LINC00173 in melanoma and elucidate its mechanisms of action.

Materials and Methods

Reverse-transcription quantitative PCR was performed to measure LINC00173 expression in melanoma. A CCK-8 assay, flow cytometry, and migration and invasion assays were applied to examine melanoma cell proliferation, apoptosis, migration, and invasion, respectively. A xenograft tumor experiment was performed to determine the tumorous growth of melanoma cells in vivo.

Results

We found that LINC00173 was upregulated in melanoma tissues and cell lines. High LINC00173 expression was closely associated with TNM stage, lymph node metastasis, and shorter overall survival of patients with melanoma. Functional assays revealed that LINC00173 downregulation inhibited melanoma cell proliferation, migration, and invasion and induced apoptosis, suggesting that LINC00173 acts as an oncogenic RNA. LINC00173 knockdown retarded the tumorous growth of melanoma cells in vivo. Mechanistically, LINC00173 increased insulin receptor substrate 4 (IRS4) expression by sponging microRNA-493 (miR-493), thereby acting as a competing endogenous RNA. The effects of LINC00173 knockdown on the malignant phenotype of melanoma cells were reversed by overexpression of IRS4 or knockdown of miR-493.

Conclusion

The LINC00173–miR-493–IRS4 pathway regulates melanoma characteristics by increasing the expression of IRS4 via competitive binding of LINC00173 to miR-493, suggesting that this pathway is a potential target for the diagnosis, prognosis, and/or treatment of melanoma.

Involvement of 27-Hydroxycholesterol in Mitotane Action on Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare cancer with poor prognosis. Mitotane, the standard treatment for ACC, impairs adrenocortical steroid biosynthesis and cholesterol metabolism. In the H295R cell line, a standard ACC in vitro model, mitotane was previously reported to enhance the production of some oxysterols. To verify the possible mechanistic involvement of oxysterols in the anti-ACC effect of mitotane, a gas chromatography mass spectrometry (GC-MS) profiling of oxysterols and the main cholesterol precursors was carried out in H295R cells. Among the oxysterols detected in mitotane-treated cells, 27OHC was markedly produced, as well as lanosterol and lathosterol cholesterol precursors. In this cell model, mitotane was confirmed to affect mitochondrial transmembrane potential and induce apoptosis. Such cytotoxic effects were perfectly matched by H295R cell treatment with a single identical micromolar amount of 27OHC. The mitotane-dependent strong increase in 27OHC was confirmed in vivo, in the plasma of ACC patients under treatment with the drug. Moreover, lanosterol, lathosterol, desmosterol and, to a minor extent, 24-hydroxycholesterol and 25-hydroxycholesterol plasma levels were significantly increased in those patients. The cytotoxic effect of mitotane on ACC cells may be partly related to the increased intracellular level of 27OHC induced by the drug itself.

Mesenchymal stem cells derived from iPSCs expressing interleukin-24 inhibit the growth of melanoma in the tumor-bearing mouse model

Background

Interleukin-24 (IL-24) is a therapeutic gene for melanoma, which can induce melanoma cell apoptosis. Mesenchymal stem cells (MSCs) show promise as a carrier to delivery anti-cancer factors to tumor tissues. Induced pluripotent stem cells (iPSCs) are an alternative source of mesenchymal stem cells (MSCs). We previously developed a novel non-viral gene targeting vector to target IL-24 to human iPSCs. This study aims to investigate whether MSCs derived from the iPSCs with the site-specific integration of IL-24 can inhibit the growth of melanoma in a tumor-bearing mouse model via retro-orbital injection.

Methods

IL-24-iPSCs were differentiated into IL-24-iMSCs in vitro, of which cellular properties and potential of differentiation were characterized. The expression of IL-24 in the IL-24-iMSCs was measured by qRT-PCR, Western Blotting, and ELISA analysis. IL-24-iMSCs were transplanted into the melanoma-bearing mice by retro-orbital intravenous injection. The inhibitory effect of IL-24-iMSCs on the melanoma cells was investigated in a co-culture system and tumor-bearing mice. The molecular mechanisms underlying IL-24-iMSCs in exerting anti-tumor effect were also explored.

Results

iPSCs-derived iMSCs have the typical profile of cell surface markers of MSCs and have the ability to differentiate into osteoblasts, adipocytes, and chondroblasts. The expression level of IL-24 in IL-24-iMSCs reached 95.39 ng/10⁶ cells/24 h, which is significantly higher than that in iMSCs, inducing melanoma cells apoptosis more effectively in vitro compared with iMSCs. IL-24-iMSCs exerted a significant inhibitory effect on the growth of melanoma in subcutaneous mouse models, in which the migration of IL-24-iMSCs to tumor tissue was confirmed. Additionally, increased expression of Bax and Cleaved caspase-3 and down-regulation of Bcl-2 were observed in the mice treated with IL-24-iMSCs.

Conclusion

MSCs derived from iPSCs with the integration of IL-24 at rDNA locus can inhibit the growth of melanoma in tumor-bearing mouse models when administrated via retro-orbital injection.

Indomethacin and juglone inhibit inflammatory molecules to induce apoptosis in colon cancer cells

Colorectal cancer (CRC) is the third most common fatal cancer. Indomethacin, a nonsteroidal anti-inflammatory drug, is known to reduce the occurrence of CRC. This study evaluated the potential anticolon cancer effects of juglone (5-hydroxy-1,4-naphthoquinone) in combination with indomethacin. Human colon adenocarcinoma cells (HT29) were subjected to treatment with indomethacin, juglone, and a combination of both. Morphological analysis, cell cycle regulation, and dual staining using acridine orange and ethidium bromide in control and treated cells revealed the apoptotic potential of these compounds. Bcl2 and inflammatory molecules (tumor necrosis factor-α, nuclear factor kappa B, and Cox-2) were found to be decreased with a concomitant increase in the expression of proapoptotic molecules (Bad, Bax, cytochrome c, and PUMA) as a result of the molecular regulation of Wnt, Notch, and peroxisome proliferator-activated receptor-γ signaling. Treatment with juglone was not as effective as with indomethacin; however, a combination of both was shown to be more effective, suggesting that juglone may be considered for therapeutic intervention of colon cancer.

Cholesterol restricts lymphotoxin β receptor-triggered NF-κB signaling

BACKGROUND

Lymphotoxin β receptor (LTβR) plays important roles in the development of the immune system and immune response. At the cellular level, ligand-bound LTβR activates the pro-inflammatory NF-κB pathway but the detailed mechanisms regulating its signaling remain unknown. Understanding them is of high importance since LTβR and its ligands are promising therapeutic targets. Here, we studied the consequences of perturbed cellular cholesterol content on LTβR-induced NF-κB signaling.

METHODS

To modulate cholesterol availability and/or level in lung carcinoma A549 and H2228, and endothelial HUVEC cells different treatment regimens with filipin, methyl-β-cyclodextrin and simvastatin were applied. LTβR localization was studied by confocal microscopy. The activity of LTβR-induced NF-κB pathway was assessed by measuring the levels of NF-κB pathway inhibitor IκBα and phosphorylation of RelA transcription factor by Western blotting. The NF-κB transcriptional response, production of chemokines and adhesion molecules were examined by qRT-PCR, ELISA, and Western blotting, respectively. Adherence of different types of primary immune cells to epithelial A549 cells and endothelial HUVECs was measured fluorometrically. Interactions of LTβR with its protein partners were investigated by immunoprecipitation.

RESULTS

We showed that filipin-mediated sequestration of cholesterol or its depletion from the plasma membrane with methyl-β-cyclodextrin impaired LTβR internalization and potentiated LTβR-dependent activation of the canonical branch of the NF-κB pathway. The latter was manifested by enhanced degradation of IκBα inhibitor, elevated RelA phosphorylation, substantial increase in the expression of NF-κB target genes encoding, among others, cytokines and adhesion molecules known to play important roles in immune response. It was followed by robust secretion of CXCL8 and upregulation of ICAM1, that favored the adhesion of immune cells (NK and T cells, neutrophils) to A549 cells and HUVECs. Mechanistically, we showed that cholesterol depletion stabilized interactions of ligand-stimulated LTβR with modified forms of TRAF2 and NEMO proteins.

CONCLUSIONS

Our results showed that the reduction of the plasma membrane content of cholesterol or its sequestration strongly potentiated signaling outcome initiated by LTβR. Thus, drugs modulating cholesterol levels could potentially improve efficacy of LTβR-based therapies. Video abstract.

Fibrin gels entrapment of a doxorubicin-containing targeted polycyclodextrin: Evaluation of in vivo antitumor activity in orthotopic models of human neuroblastoma

In vivo local antitumor activity of fibrin gels (FBGs) loaded with the poly-cyclodextrin oCD-NH₂/Dox, compared to free Dox, was evaluated in two mouse orthotopic neuroblastoma (NB) models, after positioning of the releasing devices in the visceral space. FBGs were prepared at the fibrinogen (FG) concentrations of 22 and 40 mg/ml clotted in the presence of 0.81 mM/mg FG Ca²⁺ and 1.32 U/mg FG thrombin. Our results indicate that FBGs loaded with oCD-NH₂/Dox and applied as neoadjuvant loco-regional treatment, show an antitumor activity significantly greater than that displayed by the same FBGs loaded with identical dose of Dox or after free Dox administered intra venous (iv). In particular, FBGs prepared at 40 mg/ml showed a slightly lower antitumor activity, although after their positioning we observed a significant initial reduction of tumor burden lasting for several days after gel implantation. FBGs at 22 mg/ml loaded with oCD-NH₂/Dox and applied after tumor removal (adjuvant treatment model) showed a significantly better antitumor activity than the iv administration of free Dox, with 90% tumor regrowth reduction compared to untreated controls. In all cases the weight loss post-treatment was limited after gel application, although in the adjuvant treatment the loss of body weight lasted longer than in the other treatment modality. In accordance with our recent published data on the low local toxic effects of FBGs, the present findings also underline an increase of the therapeutic index of Dox when locally administered through FBGs loaded with the oCD-NH₂/Dox complex.

β-Asarone increases doxorubicin sensitivity by suppressing NF-κB signaling and abolishes doxorubicin-induced enrichment of stem-like population by destabilizing Bmi1

Background

Lymphoma is one of the most common hematologic malignancy. Drug resistance is the main obstacle faced in lymphoma treatment. Cancer stem cells are considered as the source of tumor recurrence, metastasis and drug resistance. The β-Asarone, a low-toxicity compound from the traditional medical herb Acorus calamus, has been shown to act as an anti-cancer reagent in various cancer types. However, the anti-cancer activities of β-Asarone in lymphoma have not been shown.

Methods

Cell counting assay was used to evaluate Raji cell proliferation. CCK8 assay was used to evaluate the cell viability. Annexin-V/PI staining and flow cytometry analysis were used to evaluate apoptosis. ALDEFLUOR assay was used to evaluate the stem-like population. Luciferase reporter assay was used to examine the activation of NF-κB signaling. Western blot and polymerase chain reaction (PCR) were used to determine the expression of interested genes.

Results

We showed that β-Asarone inhibited proliferation and induced apoptosis in Raji lymphoma cells in a dose-dependent manner. Additionally, β-Asarone functioned as a sensitizer of doxorubicin and resulted in synergistic effects on inhibition of proliferation and induction of apoptosis when combined with doxorubicin treatment. Interestingly, we found that β-Asarone also reduced the stem-like population of Raji lymphoma cells in a dose-dependent manner, and suppressed the expression of c-Myc and Bmi1. Importantly, β-Asarone abolished doxorubicin-induced enrichment of the stem-like population. In the mechanism study, we revealed that β-Asarone suppressed not only basal NF-κB activity but also Tumor necrosis factor α (TNF-α) induced NF-κB activity. Moreover, blocking NF-κB signaling inactivation was critical for β-Asarone induced apoptosis and inhibition of proliferation, but not for the effect on β-Asarone reduced stem-like population. In fact, β-Asarone suppressed stem-like population by destabilizing Bmi1 via a proteasome-mediated mechanism.

Conclusions

Our data suggested the application of β-Asarone to lower the toxic effect of doxorubicin and increase the sensitivity of doxorubicin in clinical treatment. More importantly, our data revealed a novel role of β-Asarone which could be used to eliminate stem-like population in lymphoma, implying that β-Asarone might reduce relapse and drug resistance.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0873-3) contains supplementary material, which is available to authorized users.

Methyl-β-cyclodextrin, an actin depolymerizer augments the antiproliferative potential of microtubule-targeting agents

Methyl-β-cyclodextrin (MCD), an established pharmacological excipient, depolymerizes the actin cytoskeleton. In this work, we investigated the effect of MCD-mediated actin depolymerization on various cellular phenotypes including traction force, cell stiffness, focal adhesions, and intracellular drug accumulation. In addition to a reduction in the contractile cellular traction, MCD acutely inhibits the maturation of focal adhesions. Alteration of contractile forces and focal adhesions affects the trypsin-mediated detachment kinetics of cells. Moreover, MCD-mediated actin depolymerization increases the intracellular accumulation of microtubule-targeting agents (MTAs) by ~50% with respect to the untreated cells. As MCD treatment enhances the intracellular concentration of drugs, we hypothesized that the MCD-sensitized cancer cells could be effectively killed by low doses of MTAs. Our results in cervical, breast, hepatocellular, prostate cancer and multidrug-resistant breast cancer cells confirmed the above hypothesis. Further, the combined use of MCD and MTAs synergistically inhibits the proliferation of tumor cells. These results indicate the potential use of MCD in combination with MTAs for cancer chemotherapy and suggest that targeting both actin and microtubules simultaneously may be useful for cancer therapy. Importantly, the results provide significant insight into the crosstalk between actin and microtubules in regulating the traction force and dynamics of cell deadhesion.

Metformin exhibited anticancer activity by lowering cellular cholesterol content in breast cancer cells

Metformin, a widely prescribed anti-diabetic drug, shows anticancer activity in various cancer types. Few studies documented that there was a decreased level of LDL and total cholesterol in blood serum of metformin users. Based on these views, this study aimed to determine if metformin exhibits anticancer activity by alleviating cholesterol level in cancer cells. The present study found that treatment of breast cancer MDA-MB-231 cells with metformin significantly decreased cholesterol content with concomitant inhibition of various cholesterol regulatory genes (e.g., HMGCoR, LDLR and SREBP1). Metformin decreased cell viability, migration and stemness in metastatic MDA-MB-231 cells. Similarly, metformin treatment suppressed expressions of anti-apoptotic genes BCL2 and Bcl-xL, and mesenchymal genes vimentin, N-cadherin, Zeb1 and Zeb2 with simultaneous enhancement of apoptotic caspase 3 and Bax, and epithelial genes E-cadherin and keratin 19 expressions, confirming an inhibitory effect of metformin in tumorigenesis. Similar to metformin, depletion of cholesterol by methyl beta cyclodextrin (MBCD) diminished cell viability, migration, EMT and stemness in breast cancer cells. Moreover, metformin-inhibited cell viability, migration, colony and sphere formations were reversed back by cholesterol treatment. Similarly, cholesterol treatment inverted metformin-reduced several gene expressions (e.g., Bcl-xL, BCL2, Zeb1, vimentin, and BMI-1). Additionally, zymography data demonstrated that cholesterol upregulated metformin-suppressed MMP activity. These findings suggested that metformin revealed anticancer activity by lowering of cholesterol content in breast cancer cells. Thus, this study, for the first time, unravelled this additional mechanism of metformin-mediated anticancer activity.

Activation of LXRɑ/β by cholesterol in malignant ascites promotes chemoresistance in ovarian cancer

Background

The purpose of this study was to investigate the role of malignant ascites tumor microenvironment in ovarian cancer progression and chemoresistance.

Methods

A total of 45 patients with ovarian cancer and three benign ascites were collected at the time of clinical intervention. Ascites cholesterol levels were quantitated using cholesterol quantitation kit and recurrence free survival (RFS) of ovarian cancer patients were collected. The sensitivity of ovarian cancer cells to cisplatin (CDDP) and paclitaxel (PAC) were assessed by viability assay, flow cytometry and protein expression. Receiver operating characteristics (ROC) curve and Youden index analysis were applied to calculate the optimal cut-off values for ascites cholesterol. Kaplan-Meier curve were applied to compare RFS between high and low ascites cholesterol levels in ovarian cancer patients.

Results

Here we show that cholesterol is elevated in malignant ascites and modulates the sensitivity of ovarian cancer cells to CDDP and PAC by upregulating the expression of drug efflux pump proteins, ABCG2 and MDR1, together with upregulation of LXRɑ/β, the cholesterol receptor. Transfection of LXRɑ/β siRNA inhibited cholesterol-induced chemoresistance and upregulation of MDR1. In addition, the cholesterol level in malignant ascites was negatively correlated with number of CDDP-induced apoptotic cell death, but not with that of PAC-induced apoptotic cell death. Cholesterol depletion by methyl beta cyclodextrin (MβCD) inhibited malignant ascites-induced chemoresistance to CDDP and upregulation of MDR1 and LXRɑ/β. For patients with ovarian cancer, high cholesterol level in malignant ascites correlated with short RFS.

Conclusions

High cholesterol in malignant ascites contributes to poor prognosis in ovarian cancer patients, partly by contributing to multidrug resistance through upregulation of MDR1 via activation of LXRɑ/β.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5152-5) contains supplementary material, which is available to authorized users.

Hepatocellular carcinoma-associated hypercholesterolemia: involvement of proprotein-convertase-subtilisin-kexin type-9 (PCSK9)

Background

PCSK9 regulates low-density lipoprotein cholesterol (LDLc) level and has been implicated in hypercholesterolemia. Aberrant plasma lipid profile is often associated with various cancers. Clinically, the relationship between altered serum lipid level and hepatocellular carcinoma (HCC) has been documented; however, the underlying cause and implications of such dyslipidemia remain unclear.

Methods

The present study includes the use of HepG2 tumor xenograft model to study the potential role of glucose (by providing 15% glucose via drinking water) in regulating PCSK9 expression and associated hypercholesterolemia. To support in vivo findings, in vitro approaches were used by incubating HCC cells in culture medium with different glucose concentrations or treating the cells with glucose uptake inhibitors. Impact of hypercholesterolemia on chemotherapy was demonstrated by exogenously providing LDLc followed by appropriate in vitro assays.

Results

We observed that serum and hepatic PCSK9 level is decreased in mice which were provided with glucose containing water. Interestingly, serum and tumor PCSK9 level was upregulated in HepG2-tumor-bearing mice having access to water containing glucose. Additionally, elevated LDLc is detected in sera of these mice. In vitro studies indicated that PCSK9 expression was increased by high glucose availability with potential involvement of reactive oxygen species (ROS) and sterol regulatory element binding protein-1 (SREBP-1). Furthermore, it is also demonstrated that pre-treatment of cells with LDLc diminishes cytotoxicity of sorafenib in HCC cells.

Conclusion

Taken together, these results suggest a regulation of PCSK9 by high glucose which could contribute, at least partly, towards understanding the cause of hypercholesterolemia in HCC and its accompanied upshots in terms of altered response of HCC cells towards cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s40170-018-0187-2) contains supplementary material, which is available to authorized users.

Involvement of Intracellular Cholesterol in Temozolomide-Induced Glioblastoma Cell Death

Glioblastoma (GBM) still carries a poor prognosis due to the refractoriness against antitumor drugs. Temozolomide (TMZ), one of the few standard therapy drugs against GBM worldwide, has only limited effect due to acquired TMZ resistance of GBM. Therefore, development of novel therapeutic methods to overcome the TMZ resistance of GBM is urgent. The brain is the most cholesterol-rich organ in the human body, so modulation of cholesterol in tumor cells originating from the brain including GBM may be a tumor-specific therapeutic strategy including enhancement of TMZ effects. The unique lipid metabolism of glioma has recently been reported, but the involvement of intracellular cholesterol in TMZ therapy is yet to be fully elucidated. This review summarizes the effect of modulation of intracellular cholesterol level on cancer therapy including GBM treatment and the implications for TMZ therapy. Our recent findings about the involvement of intracellular cholesterol in TMZ-induced GBM cell death are described.

C-Cbl reverses HER2-mediated tamoxifen resistance in human breast cancer cells

Background

Tamoxifen is a frontline therapy for estrogen receptor (ER)-positive breast cancer in premenopausal women. However, many patients develop resistance to tamoxifen, and the mechanism underlying tamoxifen resistance is not well understood. Here we examined whether ER-c-Src-HER2 complex formation is involved in tamoxifen resistance.

Methods

MTT and colony formation assays were used to measure cell viability and proliferation. Western blot was used to detect protein expression and protein complex formations were detected by immunoprecipitation and immunofluorescence. SiRNA was used to examine the function of HER2 in of BT474 cells. An in vivo xenograft animal model was established to examine the role of c-Cbl in tumor growth.

Results

MTT and colony formation assay showed that BT474 cells are resistant to tamoxifen and T47D cells are sensitive to tamoxifen. Immunoprecipitation experiments revealed ER-c-Src-HER2 complex formation in BT474 cells but not in T47D cells. However, ER-c-Src-HER2 complex formation was detected after overexpressing HER2 in T47D cells and these cells were more resistant to tamoxifen. HER2 knockdown by siRNA in BT474 cells reduced ER-c-Src-HER2 complex formation and reversed tamoxifen resistance. ER-c-Src-HER2 complex formation was also disrupted and tamoxifen resistance was reversed in BT474 cells by the c-Src inhibitor PP2 and HER2 antibody trastuzumab. Nystatin, a lipid raft inhibitor, reduced ER-c-Src-HER2 complex formation and partially reversed tamoxifen resistance. ER-c-Src-HER2 complex formation was disrupted by overexpression of c-Cbl but not by the c-Cbl ubiquitin ligase mutant. In addition, c-Cbl could reverse tamoxifen resistance in BT474 cells, but the ubiquitin ligase mutant had no effect. The effect of c-Cbl was validated in BT474 tumor-bearing nude mice in vivo. Immunofluorescence also revealed ER-c-Src-HER2 complex formation was reduced in tumor tissues of nude mice with c-Cbl overexpression.

Conclusions

Our results suggested that c-Cbl can reverse tamoxifen resistance in HER2-overexpressing breast cancer cells by inhibiting the formation of the ER-c-Src-HER2 complex.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4387-5) contains supplementary material, which is available to authorized users.

Proton and Carbon-13 Dynamic Nuclear Polarization of Methylated β-Cyclodextrins

¹H and ¹³C dynamic nuclear polarizations have been studied in ¹³C-enriched β-cyclodextrins doped with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl free radical. ¹H and ¹³C polarizations raised above 7.5 and 7%, respectively, and for both nuclear species, the transfer of polarization from the electron spins appears to be consistent with a thermal mixing scenario for a concentration of 9 ¹³C nuclei per molecule. When the concentration is increased to 21 ¹³C nuclei per molecule, a decrease in the spin-lattice relaxation and polarization buildup rates is observed. This reduction is associated with the bottleneck effect induced by the decrease in the number of electron spins per nucleus when both the nuclear spin-lattice relaxation and the polarization occur through the electron non-Zeeman reservoir. ¹³C nuclear spin-lattice relaxation has been studied in the 1.8-340 K range, and the effects of internal molecular motions and of the free radicals on the relaxation are discussed. ¹³C hyperpolarization performances and room-temperature spin-lattice relaxation times show that these are promising materials for future biomedical applications.

Membrane cholesterol depletion in cortical neurons highlights altered NMDA receptor functionality in a mouse model of amyotrophic lateral sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a chronic neurodegenerative disease affecting upper and lower motor neurons, with unknown aetiology. Lipid rafts, cholesterol enriched microdomains of the plasma membrane, have been linked to neurodegenerative disorders like ALS. The NMDA-receptor subcellular localization in lipid rafts is known to play many roles, from modulating memory strength to neurotoxicity. In this study, performed on the widely used G93A mouse model of ALS, we have shown an equal content of total membrane cholesterol in Control and G93A cortical cultures. Moreover, by electrophysiological studies, we have recorded NMDA- and AMPA-evoked currents which were not significantly different between the two neuronal populations. To study the role of membrane cholesterol on glutamate receptor functionality, we have analysed NMDA and AMPA receptors following cholesterol membrane depletion by methyl-β-cyclodextrin (MβCD). Interestingly, MβCD chronic treatment has provoked a significant reduction of NMDA-evoked currents in both cellular populations which was dose- and time-dependent but significantly higher in ALS neurons compared to Control. The different MβCD effect on NMDA-evoked currents was not due to a different membrane receptor subunit composition but seemed to cause in both neuronal populations a NMDA receptor membrane redistribution. MβCD treatment effect was receptor-specific since no alterations in the two neuronal populations were detected on AMPA receptors. These results lead us to speculate for an altered proteomic composition of lipid rafts in cortical mutated neurons and suggest the need for further studies on the lipid rafts composition and on their interaction with membrane receptors in ALS cortices.

Amphiphilic cyclodextrin nanoparticles

Cyclodextrins are cyclic oligosaccharides obtained by enzymatic digestion of starch. The α-, β- and γ- cyclodextrins contain respectively 6, 7 and 8 glucopyranose units, with primary and secondary hydroxyl groups located on the narrow and wider rims of a truncated cone shape structure. Such structure is that of a hydrophobic inner cavity with a hydrophilic outer surface allowing to interact with a wide range of molecules like ions, protein and oligonucleotides to form inclusion complexes. Many cyclodextrin applications in the pharmaceutical area have been widely described in the literature due to their low toxicity and low immunogenicity. The most important is to increase the solubility of hydrophobic drugs in water. Chemically modified cyclodextrin derivatives have been synthesized to enhance their properties and more specifically their pharmacological activity. Among these, amphiphilic derivatives were designed to build organized molecular structures, through selfassembling systems or by incorporation in lipid membranes, expected to improve the vectorization in the organism of the drug-containing cyclodextrin cavities. These derivatives can form a variety of supramolecular structures such as micelles, vesicles and nanoparticles. The purpose of this review is to summarize applications of amphiphilic cyclodextrins in different areas of drug delivery, particularly in protein and peptide drug delivery and gene delivery. The article highlights important amphiphilic cyclodextrin applications in the design of novel delivery systems like nanoparticles.

Effects of MβCD on Lipoxygenase-Induced LDL Oxidation

Beta-cyclodextrin (β-CD) has been applied as drug/food carriers or potential drugs for treating some diseases. Most recently, some evidence indicated that methyl-β-cyclodextrin (MβCD) and 2-hydroxypropyl-β-cyclodextrin (2-HPβCD), two major derivatives of β-CD, may inhibit atherogenesis, implying that cyclodextrins also can be potential drugs for treating atherosclerosis. It is well known that modification (e.g. oxidation) of low-density lipoprotein (LDL) is one of the most critical steps of atherogenesis. Lipoxygenase, an enzyme able to be expressed by atherosclerosis-related vascular cells, is generally regarded as a possible in vivo agent of LDL oxidation. In this study, the effects of MβCD on LDL oxidation induced by lipoxygenase were investigated by measuring the electrophoretic mobility, conjugated diene formation, malondialdehyde (MDA) production, and amino group blockage of LDL. We found that the lipids depleted from LDL by MβCD could be oxygenated more readily by lipoxygenase whereas the lipoxygenase-induced oxidation of the remaining lipid-depleted LDL decreased. The data imply that MβCD has an inhibitory effect on lipoxygenase-induced LDL oxidation and probably helps to inhibit atherogenesis.

Methyl-β-Cyclodextrin Impairs the Monocyte-Adhering Ability of Endothelial Cells by Down-Regulating Adhesion Molecules and Caveolae and Reorganizing the Actin Cytoskeleton

Due to its powerful ability to deplete cholesterol from the plasma membrane of cells, methyl-β-cyclodextrin (MβCD) has been widely used as a putative research tool in cell biology. Recently, recruiting MβCD as an effective drug (e.g., antitumor drugs) has been developed. However, it remains unclear whether MβCD, when it enters the blood circulation as a drug, influences the functions of the endothelium, e.g., the adhesion of leukocytes to the endothelium. In this study, we found that MβCD can impair the adhesion of monocytes to the monolayer of endothelial cells by lowering the cell-surface adhesive force and expression of adhesion molecules and caveolae-related molecules on/in endothelial cells, and reorganizing the actin cytoskeleton of endothelial cells. The data imply that MβCD, when recruited as a drug, potentially helps to inhibit inflammation or initiation/progression of atherosclerosis since its important early step is the adhesion of circulating leukocytes (e.g., monocytes) to the endothelium.

The Potential of Cyclodextrins as Novel Active Pharmaceutical Ingredients: A Short Overview

Cyclodextrins (CDs) are cyclic oligosaccharides of natural origin that were discovered more than 100 years ago. The peculiar cone-like conformation of the sugar ring, expressing a lipophilic cavity and a hydrophilic external surface, allows these substances to spontaneously complex poorly soluble compounds in an aqueous environment. For more than 50 years, these substances have found applicability in the pharmaceutical and food industries as solubilizing agents for poorly soluble chemical entities. Nowadays, several research groups all over the world are investigating their potential as active pharmaceutical ingredients (APIs) for the treatment of several illnesses (e.g., hypercholesterolemia, cancer, Niemann-Pick Type C disease). The aim of this review is to briefly retrace cyclodextrins’ legacy as complexing agents and describe the current and future prospects of this class of chemical entities in pharmaceutics as new APIs.

Lipid Raft Integrity Is Required for Survival of Triple Negative Breast Cancer Cells

Purpose

Lipid rafts are cholesterol enriched microdomains that colocalize signaling pathways involved in cell proliferation, metastasis, and angiogenesis. We examined the effect of methyl-β-cyclodextrin (MβCD)-mediated cholesterol extraction on the proliferation, adhesion, invasion, and angiogenesis of triple negative breast cancer (TNBC) cells.

Methods

We measured cholesterol and estimated cell toxicity. Detergent resistant membrane (DRM) and non-DRM fractions were separated using the OptiPrep gradient method. Cell cycles stages were analyzed by flow cytometry, apoptosis was assessed using the TdT-mediated dUTP nick end-labeling assay, and metastasis was determined using a Matrigel invasion assay. Neo-vessel pattern and levels of angiogenic modulators were determined using an in vitro angiogenesis assay and an angiogenesis array, respectively.

Results

The present study found that the cholesterol-depleting agent MβCD, efficiently depleted membrane cholesterol and caused concentration dependent (0.1–0.5 mM) cytotoxicity compared to nystatin and filipin III in TNBC cell lines, MDA-MB 231 and MDA-MB 468. A reduced proportion of caveolin-1 found in DRM fractions indicated a cholesterol extraction-induced disruption of lipid raft integrity. MβCD inhibited 52% of MDA-MB 231 cell adhesion on fibronectin and 56% of MDA-MB 468 cell adhesion on vitronectin, while invasiveness of these cells was decreased by 48% and 52% respectively, following MβCD treatment (48 hours). MβCD also caused cell cycle arrest at the G₂M phase and apoptosis in MDA-MB 231 cells (25% and 58% cells, respectively) and in MDA-MB 468 cells (30% and 38% cells, respectively). We found that MβCD treated cells caused a 52% and 58% depletion of neovessel formation in both MDA-MB 231 and MDA-MB 468 cell lines, respectively. This study also demonstrated that MβCD treatment caused a respective 2.6- and 2.5-fold depletion of tyrosine protein kinase receptor (TEK) receptor tyrosine kinase levels in both TNBC cell lines.

Conclusion

MβCD-induced cholesterol removal enhances alterations in lipid raft integrity, which reduces TNBC cell survival.

Identification of CETP as a molecular target for estrogen positive breast cancer cell death by cholesterol depleting agents

Cholesterol and its metabolites act as steroid hormone precursors, which promote estrogen receptor positive (ER+) breast cancer (BC) progression. Development of cholesterol targeting anticancer drugs has been hindered due to the lack of knowledge of viable molecular targets. Till now, Cholesteryl ester transfer protein (CETP) has been envisaged as a feasible molecular target in atherosclerosis, but for the first time, we show that CETP contributes to BC cell survival when challenged with cholesterol depleting agents. We show that MCF-7 CETP knockout BC cells pose less resistance towards cytotoxic compounds (Tamoxifen and Acetyl Plumbagin (AP)), and were more susceptible to intrinsic apoptosis. Analysis of differentially expressed genes using Ingenuity Pathway Analysis (IPA), in vivo tumor inhibition, and in vitro phenotypic responses to AP revealed a unique CETP-centric cholesterol pathway involved in sensitizing ER+ BC cells to intrinsic mitochondrial apoptosis. Furthermore, analysis of cell line, tissue and patient data available in publicly available databases linked elevated CETP expression to cancer, cancer relapse and overall poor survival. Overall, our findings highlight CETP as a pharmacologically relevant and unexploited cellular target in BC. The work also highlights AP as a promising chemical entity for preclinical investigations as a cholesterol depleting anticancer therapeutic agent.

4-cholesten-3-one suppresses lung adenocarcinoma metastasis by regulating translocation of HMGB1, HIF1α and Caveolin-1

Metastasis is a great challenge in lung adenocarcinoma (ADC) therapy. Cholesterol has been implicated in ADC metastasis. 4-cholesten-3-one, as cholesterol metabolite and analog, can substitute membrane cholesterol and increase membrane fluidity. In this study, we explored the possibility that 4-cholesten-3-one inhibited ADC metastasis. Low-dose 4-cholesten-3-one significantly restrained ADC cells migration and invasion with little effects on cells viabilities. Further investigation showed that 4-cholesten-3-one promoted ROS generation, which transiently activated AMPKα1, increased HIF1α expression, reduced Bcl-2 expression and caused autophagy. AMPKα1 knockdown partly suppressed 4-cholesten-3-one-induced autophagy but, neither prevented 4-cholesten-3-one-induced upregulation of HIF1α or downregulation of Bcl-2. 4-cholesten-3-one-induced autophagy facilitated the release of HMGB1 from nuclei to cytoplasm, blocking nuclear translocation of HIF1α and activation of MMP2 and MMP9. Also, 4-cholesten-3-one induced time-dependent phosphorylation of caveolin-1, Akt and NF-κB. With increasing treatment time, 4-cholesten-3-one accelerated caveolin-1 internalization, but reduced the phosphorylation of Akt and NF-κB, and inhibited the expression of snail and twist. These data suggested that 4-cholesten-3-one could be a potential candidate for anti-metastasis of lung adenocarcinoma.

Glucose induced activation of canonical Wnt signaling pathway in hepatocellular carcinoma is regulated by DKK4

Elevated glycemic index, an important feature of diabetes is implicated in an increased risk of hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of this association are relatively less explored. Present study investigates the effect of hyperglycemia over HCC proliferation. We observed that high glucose culture condition (HG) specifically activates canonical Wnt signaling in HCC cells, which is mediated by suppression of DKK4 (a Wnt antagonist) expression and enhanced β-catenin level. Functional assays demonstrated that a normoglycemic culture condition (NG) maintains constitutive expression of DKK4, which controls HCC proliferation rate by suppressing canonical Wnt signaling pathway. HG diminishes DKK4 expression leading to loss of check at G0/G1/S phases of the cell cycle thereby enhancing HCC proliferation, in a β-catenin dependent manner. Interestingly, in NOD/SCID mice supplemented with high glucose, HepG2 xenografted tumors grew rapidly in which elevated levels of β-catenin, c-Myc and decreased levels of DKK4 were detected. Knockdown of DKK4 by shRNA promotes proliferation of HCC cells in NG, which is suppressed by treating cells exogenously with recombinant DKK4 protein. Our in vitro and in vivo results indicate an important functional role of DKK4 in glucose facilitated HCC proliferation.

Effects of cyclodextrins on the structure of LDL and its susceptibility to copper-induced oxidation

Cyclodextrins (CDs) have long been widely used as drug/food carriers and were recently developed as drugs for the treatment of diseases (e.g. Niemann-Pick C1 and cancers). It is unknown whether cyclodextrins may influence the structure of low-density lipoprotein (LDL), its susceptibility to oxidation, and atherogenesis. In this study, four widely used cyclodextrins including α-CD, γ-CD, and two derivatives of β-CD (HPβCD and MβCD) were recruited. Interestingly, agarose gel electrophoresis (staining lipid and protein components of LDL with Sudan Black B and Coomassie brilliant blue, respectively but simultaneously) shows that cyclodextrins at relatively high concentrations caused disappearance of the LDL band and/or appearance of an additional protein-free lipid band, implying that cyclodextrins at relatively high concentrations can induce significant electrophoresis-detectable lipid depletion of LDL. Atomic force microscopy (AFM) detected that MβCD (as a representative of cyclodextrins) induced size decrease of LDL particles in a dose-dependent manner, further confirming the lipid depletion effects of cyclodextrins. Moreover, the data from agarose gel electrophoresis, conjugated diene formation, MDA production, and amino group blockage of copper-oxidized LDL show that cyclodextrins can impair LDL susceptibility to oxidation. It implies that cyclodextrins probably help to inhibit atherogenesis by lowering LDL oxidation.

Loss-of-function Mutation in PMVK Causes Autosomal Dominant Disseminated Superficial Porokeratosis

Disseminated superficial porokeratosis (DSP) is a rare keratinization disorder of the epidermis. It is characterized by keratotic lesions with an atrophic center encircled by a prominent peripheral ridge. We investigated the genetic basis of DSP in two five-generation Chinese families with members diagnosed with DSP. By whole-exome sequencing, we sequencing identified a nonsense variation c.412C > T (p.Arg138*) in the phosphomevalonate kinase gene (PMVK), which encodes a cytoplasmic enzyme catalyzing the conversion of mevalonate 5-phosphate to mevalonate 5-diphosphate in the mevalonate pathway. By co-segregation and haplotype analyses as well as exclusion testing of 500 normal control subjects, we demonstrated that this genetic variant was involved in the development of DSP in both families. We obtained further evidence from studies using HaCaT cells as models that this variant disturbed subcellular localization, expression and solubility of PMVK. We also observed apparent apoptosis in and under the cornoid lamella of PMVK-deficient lesional tissues, with incomplete differentiation of keratinocytes. Our findings suggest that PMVK is a potential novel gene involved in the pathogenesis of DSP and PMVK deficiency or abnormal keratinocyte apoptosis could lead to porokeratosis.

Lipid metabolic reprogramming in cancer cells

Many human diseases, including metabolic, immune and central nervous system disorders, as well as cancer, are the consequence of an alteration in lipid metabolic enzymes and their pathways. This illustrates the fundamental role played by lipids in maintaining membrane homeostasis and normal function in healthy cells. We reviewed the major lipid dysfunctions occurring during tumor development, as determined using systems biology approaches. In it, we provide detailed insight into the essential roles exerted by specific lipids in mediating intracellular oncogenic signaling, endoplasmic reticulum stress and bidirectional crosstalk between cells of the tumor microenvironment and cancer cells. Finally, we summarize the advances in ongoing research aimed at exploiting the dependency of cancer cells on lipids to abolish tumor progression.

Functionalization of Cyclodextrins with N-Hydroxyphthalimide Moiety: A New Class of Supramolecular Pro-Oxidant Organocatalysts

N-hydroxyphthalimide (NHPI) is an organocatalyst for free-radical processes able to promote the aerobic oxidation of a wide range of organic substrates. In particular, NHPI can catalyze the hydroperoxidation of polyunsaturated fatty acids (PUFA). This property could be of interest for biological applications. This work reports the synthesis of two β-cyclodextrin derivatives (CD5 and CD6) having a different degree of methylation and bearing a NHPI moiety. These compounds, having different solubility in water, have been successfully tested for the hydroperoxidation of methyl linoleate, chosen as the PUFA model molecule.

Strategy to enhance efficacy of doxorubicin in solid tumor cells by methyl-β-cyclodextrin: Involvement of p53 and Fas receptor ligand complex

Doxorubicin (DOX) is one of the preferred drugs for treating breast and liver cancers. However, its clinical application is limited due to severe side effects and the accompanying drug resistance. In this context, we investigated the effect on therapeutic efficacy of DOX by cholesterol depleting agent methyl-β-cyclodextrin (MCD), and explored the involvement of p53. MCD sensitizes MCF-7 and Hepa1–6 cells to DOX, Combination of MCD and marginal dose of DOX reduces the cell viability, and promoted apoptosis through induction of pro-apoptotic protein, Bax, activation of caspase-8 and caspase-7, down regulation of anti-apoptotic protein Bcl-2 and finally promoting PARP cleavage. Mechanistically, sensitization to DOX by MCD was due to the induction of FasR/FasL pathway through p53 activation. Furthermore, inhibition of p53 by pharmacological inhibitor pifithrin-α (PFT-α) or its specific siRNA attenuated p53 function and down-regulated FasR/FasL, thereby preventing cell death. Animal experiments were performed using C57BL/6J mouse isografted with Hepa1–6 cells. Tumor growth was retarded and survival increased in mice administered MCD together with DOX to as compared to either agent alone. Collectively, these results suggest that MCD enhances the sensitivity to DOX for which wild type p53 is an important determinant.

The antitumor effects of methyl-β-cyclodextrin against primary effusion lymphoma via the depletion of cholesterol from lipid rafts

Primary effusion lymphoma (PEL) is a subtype of aggressive and chemotherapy-resistant non-Hodgkin lymphoma that occurs predominantly in patients with advanced AIDS. In this study, we examined the antitumor activity of methyl-β-cyclodextrin (M-β-CyD) in vitro and in vivo. M-β-CyD quickly induced caspase-dependent apoptosis in PEL cells via cholesterol depletion from the plasma membrane. In a PEL xenograft mouse model, M-β-CyD significantly inhibited the growth and invasion of PEL cells without apparent adverse effects. These results strongly suggest that M-β-CyD has the potential to be an effective antitumor agent against PEL.

Iron granules in plasma cells

Resistance of cancer cells to chemotherapy is the first cause of cancer-associated death. Thus, new strategies to deal with the evasion of drug response and to improve clinical outcomes are needed. Genetic and epigenetic mechanisms associated with uncontrolled cell growth result in metabolism reprogramming. Cancer cells enhance anabolic pathways and acquire the ability to use different carbon sources besides glucose. An oxygen and nutrient-poor tumor microenvironment determines metabolic interactions among normal cells, cancer cells and the immune system giving rise to metabolically heterogeneous tumors which will partially respond to metabolic therapy. Here we go into the best-known cancer metabolic profiles and discuss several studies that reported tumors sensitization to chemotherapy by modulating metabolic pathways. Uncovering metabolic dependencies across different chemotherapy treatments could help to rationalize the use of metabolic modulators to overcome therapy resistance.