alpha-Lipoic acid induces apoptosis in human colon cancer cells by increasing mitochondrial respiration with a concomitant O2-*-generation

Anticancer effects of alpha-lipoic acid, a potent organosulfur compound by modulating matrix metalloproteinases and apoptotic markers in osteosarcoma MG-63 cells

Osteosarcoma (OS), an extremely aggressive form of bone tumor primarily affects young adults. Despite significant advancements in clinical trials, the ability of cancer cells to metastasize and resist apoptosis remains a major challenge. To address these issues, novel therapeutic interventions with high specificity for these processes are essential. Alpha-lipoic acid (ALA), an organosulfur compound derived from octanoic acid, possesses a range of pharmacological properties. This study hypothesizes that ALA would inhibit metastasis and induce cell apoptosis in OS. To evaluate the potential of ALA, its effects on the migration, metastasis, and cell cycle of MG-63 OS cells were assessed, along with its ability to trigger apoptosis. To these aims, MG-63 cells were exposed to varying concentrations of ALA, and cell viability was measured using the alamarBlue assay. The impact of ALA on cell cycle progression, apoptosis, migration, and metastasis was analyzed through flow cytometry, scratch assay, and gelatin zymography. After validating the expression of MMP2, MMP9, VEGF, VEGFR, BAX, BCL-2, and P53 by the GEO database, the expression levels of these genes were examined through quantitative PCR (qPCR). Eventually, molecular docking was employed to simulate the interactions between ALA and matrix metalloproteinase (MMPs). The results demonstrated that ALA significantly inhibited cell migration, induced cell cycle arrest, and promoted apoptosis by upregulating P53 and BAX expression while downregulating BCL-2 levels. Furthermore, ALA was found to suppress the activity and expression of MMP2 and MMP9 and reduce the expression of angiogenesis markers. Notably, ALA interacted directly with the active site of MMP2 and MMP9. These findings suggest that ALA has the potential to be a promising agent with anti-cancer effects on MG-63 cells, warranting further preclinical investigations.

Aqueous phase transfer of near-infrared ZnCuInS2/ZnS quantum dots: Synthesis and characterization

Cadmium-free and NIR fluorescent QDs are promising candidates for bio-application. Thus, we present the synthesis of ternary ZnCuInS2/ZnS (ZCIS/ZnS) quantum dots (QDs) where the molar variation of Cu/Zn of the precursors was used to tune the optical and structural properties. QDs with Cu/Zn molar ratio of 2/1 passivated with ZnS exhibited the best optical properties. They showed dominant near-infrared photoluminescence (approx. 850 nm) and highest quantum yield (approx. 52 %, λexc = 500 nm). Therefore, they were further subject to modification to ensure their transfer to the aqueous phase and improve biocompatibility. For this, different functionalization approaches were used. The first method relied on encapsulation with polymers like PSMA (poly(styrene co-maleic anhydride)) and PMAO (poly(maleic anhydride-alt-1-octadecene) coupled with polyetheramine (JEFF; Jeffamine M-1000), and the second relied on hydrophilization with PMAO. Furthermore, we also applied a surface ligand exchange process using DHLA (dihydrolipoic acid) and polyethylene glycol (PEG)-appended DHLA. The comprehensive study indicated that ZnCuInS2/ZnS QDs functionalized with PMAO (ZnCuInS2/ZnS@PMO) exhibited the highest photoluminescence (PL QY) along with ensured high colloidal stability in aqueous media. Moreover, no noticeable deterioration of the photoluminescence profile was observed for all used functionalization approaches. However, a significant decrease in QY was observed for almost all functionalized QDs except those that were PMO-capped. The synthesized QDs were systematically characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), UV-Vis absorption spectroscopy, and fluorescence spectroscopy. Biological studies indicate that the obtained hydrophilic ZCIS QDs are biocompatible and localized intracellularly inside endosomes.

From Lipid Signatures to Cellular Responses: Unraveling the Complexity of Melanoma and Furthering Its Diagnosis and Treatment

Recent advancements in mass spectrometry have significantly enhanced our understanding of complex lipid profiles, opening new avenues for oncological diagnostics. This review highlights the importance of lipidomics in the comprehension of certain metabolic pathways and its potential for the detection and characterization of various cancers, in particular melanoma. Through detailed case studies, we demonstrate how lipidomic analysis has led to significant breakthroughs in the identification and understanding of cancer types and its potential for detecting unique biomarkers that are instrumental in its diagnosis. Additionally, this review addresses the technical challenges and future perspectives of these methodologies, including their potential expansion and refinement for clinical applications. The discussion underscores the critical role of lipidomic profiling in advancing cancer diagnostics, proposing a new paradigm in how we approach this devastating disease, with particular emphasis on its application in comparative oncology.

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

Anti-cancer effects of alpha lipoic acid, cisplatin and paclitaxel combination in the OVCAR-3 ovarian adenocarcinoma cell line

BACKGROUND

Ovarian cancer is the leading cause of gynecological cancer deaths. One of the major challenges in treating ovarian cancer with chemotherapy is managing the resistance developed by cancer cells to drugs, while also minimizing the side effects caused by these agents In the present study, we aimed to examine the effects of a combination of alpha lipoic acid (ALA), with cisplatin and paclitaxel in ovarian cancer(OVCAR-3).

METHODS

The cytotoxic effects of ALA, cisplatin and paclitaxel on OVCAR-3 cells were determined. Four groups were formed: Control, ALA, Cisplatin + Paclitaxel, ALA + Cisplatin + Paclitaxel. The effects of single and combined therapy on cell migration, invasion and colony formation were analyzed. Changes in the expression of genes related to apoptosis, cell adhesion and cell cycle were analyzed with Real-time polymerase chain reaction(RT-PCR). The oxidative stress index and The Annexin V test were performed.

RESULTS

The reduction in rapamycin-insensitive companion of mTOR(RICTOR) expression in the ALA + Cisplatin + Paclitaxel group was found statistically significant(p < 0.05). The decrease in MMP-9 and - 11 expressions the ALA + Cisplatin + Paclitaxel group was statistically significant(p < 0.05). The lowest values for mitogen-activated protein kinase(MAPK) proteins were found in the ALA + Cisplatin + Paclitaxel group. No colony formation was observed in the Cisplatin + Paclitaxel and ALA + Cisplatin + Paclitaxel groups. The lowest wound healing at 24 h was seen in the ALA + Cisplatin + Paclitaxel group.

CONCLUSIONS

This study is the first one to investigate the combined treatment of ALA, Cisplatin, Paclitaxel on OVCAR-3. While ALA alone was not effective, combined therapy with ALA, has been found to reduce cell invasion, especially wound healing in the first 24 h, along with tumor cell adhesion.

α-lipoic acid modulates prostate cancer cell growth and bone cell differentiation

Prostate cancer (PCa) progression leads to bone modulation in approximately 70% of affected men. A nutraceutical, namely, α-lipoic acid (α-LA), is known for its potent anti-cancer properties towards various cancers and has been implicated in treating and promoting bone health. Our study aimed to explore the molecular mechanism behind the role of α-LA as therapeutics in preventing PCa and its associated bone modulation. Notably, α-LA treatment significantly reduced the cell viability, migration, and invasion of PCa cell lines in a dose-dependent manner. In addition, α-LA supplementation dramatically increased reactive oxygen species (ROS) levels and HIF-1α expression, which started the downstream molecular cascade and activated JNK/caspase-3 signaling pathway. Flow cytometry data revealed the arrest of the cell cycle in the S-phase, which has led to apoptosis of PCa cells. Furthermore, the results of ALP (Alkaline phosphatase) and TRAP (tartrate-resistant acid phosphatase) staining signifies that α-LA supplementation diminished the PCa-mediated differentiation of osteoblasts and osteoclasts, respectively, in the MC3T3-E1 and bone marrow macrophages (BMMs) cells. In summary, α-LA supplementation enhanced cellular apoptosis via increased ROS levels, HIF-1α expression, and JNK/caspase-3 signaling pathway in advanced human PCa cell lines. Also, the treatment of α-LA improved bone health by reducing PCa-mediated bone cell modulation.

Targeting the Metabolic Paradigms in Cancer and Diabetes

Dysregulated metabolic dynamics are evident in both cancer and diabetes, with metabolic alterations representing a facet of the myriad changes observed in these conditions. This review delves into the commonalities in metabolism between cancer and type 2 diabetes (T2D), focusing specifically on the contrasting roles of oxidative phosphorylation (OXPHOS) and glycolysis as primary energy-generating pathways within cells. Building on earlier research, we explore how a shift towards one pathway over the other serves as a foundational aspect in the development of cancer and T2D. Unlike previous reviews, we posit that this shift may occur in seemingly opposing yet complementary directions, akin to the Yin and Yang concept. These metabolic fluctuations reveal an intricate network of underlying defective signaling pathways, orchestrating the pathogenesis and progression of each disease. The Warburg phenomenon, characterized by the prevalence of aerobic glycolysis over minimal to no OXPHOS, emerges as the predominant metabolic phenotype in cancer. Conversely, in T2D, the prevailing metabolic paradigm has traditionally been perceived in terms of discrete irregularities rather than an OXPHOS-to-glycolysis shift. Throughout T2D pathogenesis, OXPHOS remains consistently heightened due to chronic hyperglycemia or hyperinsulinemia. In advanced insulin resistance and T2D, the metabolic landscape becomes more complex, featuring differential tissue-specific alterations that affect OXPHOS. Recent findings suggest that addressing the metabolic imbalance in both cancer and diabetes could offer an effective treatment strategy. Numerous pharmaceutical and nutritional modalities exhibiting therapeutic effects in both conditions ultimately modulate the OXPHOS-glycolysis axis. Noteworthy nutritional adjuncts, such as alpha-lipoic acid, flavonoids, and glutamine, demonstrate the ability to reprogram metabolism, exerting anti-tumor and anti-diabetic effects. Similarly, pharmacological agents like metformin exhibit therapeutic efficacy in both T2D and cancer. This review discusses the molecular mechanisms underlying these metabolic shifts and explores promising therapeutic strategies aimed at reversing the metabolic imbalance in both disease scenarios.

Alpha-Lipoic Acid Reduces Cell Growth, Inhibits Autophagy, and Counteracts Prostate Cancer Cell Migration and Invasion: Evidence from In Vitro Studies

Alpha-lipoic acid (ALA) is a natural antioxidant dithiol compound, exerting antiproliferative and antimetastatic effects in various cancer cell lines. In our study, we demonstrated that ALA reduces the cell growth of prostate cancer cells LNCaP and DU-145. Western blot results revealed that in both cancer cells, ALA, by upregulating pmTOR expression, reduced the protein content of two autophagy initiation markers, Beclin-1 and MAPLC3. Concomitantly, MTT assays showed that chloroquine (CQ) exposure, a well-known autophagy inhibitor, reduced cells' viability. This was more evident for treatment using the combination ALA + CQ, suggesting that ALA can reduce cells' viability by inhibiting autophagy. In addition, in DU-145 cells we observed that ALA affected the oxidative/redox balance system by deregulating the KEAP1/Nrf2/p62 signaling pathway. ALA decreased ROS production, SOD1 and GSTP1 protein expression, and significantly reduced the cytosolic and nuclear content of the transcription factor Nrf2, concomitantly downregulating p62, suggesting that ALA disrupted p62-Nrf2 feedback loop. Conversely, in LNCaP cells, ALA exposure upregulated both SOD1 and p62 protein expression, but did not affect the KEAP1/Nrf2/p62 signaling pathway. In addition, wound-healing, Western blot, and immunofluorescence assays evidenced that ALA significantly reduced the motility of LNCaP and DU-145 cells and downregulated the protein expression of TGFβ1 and vimentin and the deposition of fibronectin. Finally, a soft agar assay revealed that ALA decreased the colony formation of both the prostate cancer cells by affecting the anchorage independent growth. Collectively, our in vitro evidence demonstrated that in prostate cancer cells, ALA reduces cell growth and counteracts both migration and invasion. Further studies are needed in order to achieve a better understanding of the underlined molecular mechanisms.

Sugiol Masters Apoptotic Precision to Halt Gastric Cancer Cell Proliferation

Sugiol, a natural compound with anticancer properties, has shown promise in various cancer types, but its potential in preventing gastric cancer remains uncertain. In this study, we aimed to examine the inhibitory effect of sugiol on human gastric cancer cell proliferation. Our findings demonstrate that sugiol effectively suppresses the proliferation of SNU-5 human gastric cancer cells, leading to apoptotic cell death. We assessed the chemo-preventive potential of sugiol via an MTT assay and confirmed the induction of oxidative stress using the H2DCFDA fluorescent dye. Treatment with sugiol at concentrations higher than 25 µM for 24 h resulted in an increase in intracellular levels of reactive oxygen species (ROS). This elevation of ROS levels inhibited cell-cycle progression and induced cell-cycle arrest at the G1 phase. Furthermore, our study revealed that sugiol reduces the viability and proliferation of SNU-5 cells in a dose-dependent manner. Importantly, ADME and toxicity analyses revealed that sugiol was effective and nontoxic at low doses. In parallel, we utilized the Swiss target prediction tool to identify potential targets for sugiol. Enzymes and nuclear receptors were identified as major targets. To gain insights into the molecular interactions, we performed structure-based molecular docking studies, focusing on the interaction between sugiol and STAT3. The docking results revealed strong binding interactions within the active site pocket of STAT3, with a binding affinity of -12.169 kcal/mole. Sugiol's -OH group, carbonyl group, and phenyl ring demonstrated hydrogen-bonding interactions with specific residues of the target protein, along with Vander Waals and hydrophobic interactions. These data suggest that sugiol has the potential to inhibit the phosphorylation of STAT3, which is known to play a crucial role in promoting the growth and survival of cancer cells. Targeting the dysregulated STAT3 signaling pathway holds promise as a therapeutic strategy for various human tumors. In combination with interventions that regulate cell cycle progression and mitigate the DNA damage response, the efficacy of these therapeutic approaches can be further enhanced. The findings from our study highlight the antiproliferative and apoptotic potential of sugiol against human gastric cancer cells (SNU-5). Moreover, the result underpins that sugiol's interactions with STAT3 may contribute to its inhibitory effects on cancer cell growth and proliferation. Further research is warranted to explore the full potential of sugiol as a therapeutic agent and its potential application in treating gastric cancer and other malignancies characterized by dysregulated STAT3 activity.

Genomic-driven nutritional interventions for radiotherapy-resistant rectal cancer patient

Radiotherapy response of rectal cancer patients is dependent on a myriad of molecular mechanisms including response to stress, cell death, and cell metabolism. Modulation of lipid metabolism emerges as a unique strategy to improve radiotherapy outcomes due to its accessibility by bioactive molecules within foods. Even though a few radioresponse modulators have been identified using experimental techniques, trying to experimentally identify all potential modulators is intractable. Here we introduce a machine learning (ML) approach to interrogate the space of bioactive molecules within food for potential modulators of radiotherapy response and provide phytochemically-enriched recipes that encapsulate the benefits of discovered radiotherapy modulators. Potential radioresponse modulators were identified using a genomic-driven network ML approach, metric learning and domain knowledge. Then, recipes from the Recipe1M database were optimized to provide ingredient substitutions maximizing the number of predicted modulators whilst preserving the recipe's culinary attributes. This work provides a pipeline for the design of genomic-driven nutritional interventions to improve outcomes of rectal cancer patients undergoing radiotherapy.

Alpha-lipoic acid induced apoptosis of PC3 prostate cancer cells through an alteration on mitochondrial membrane depolarization and MMP-9 mRNA expression

Cancer has become an important cause of mortality and morbidity in the world. Over the past decades, biomedical research revealed insights into the molecular events and signaling pathways involved in carcinogenesis and cancer progression. Matrix metalloproteinases (MMPs) are a diverse family of enzymes that can degrade various components of the extracellular matrix and are considered as potential diagnostic and prognostic biomarkers for many cancer types and cancer stages. Recently, studies on the role of natural-origin active substances in the prevention of cancer development gained importance. Among them, the α-lipoic acid, which is commonly found in plants, displayed potent anti-proliferative effects on cancer cell lines. However, the effect of the compound on the induction of apoptosis and mRNA expression of MMPs in human prostate cancer cells remains unclear. The present study aimed to evaluate the anti-proliferative and apoptotic activity of α-lipoic acid in human PC3 prostate carcinoma cells considering different concentrations and exposure durations. The findings showed that, α-lipoic acid significantly decreased PC3 cell viability with an IC₅₀ value of 1.71 mM at 48 h (p < 0.05). Additionally, the compound significantly increased Annexin-V binding in cells compared to control and induced a significant alteration in mitochondrial membrane potential and caspase levels (p < 0.05). Furhermore, the RT-PCR analyses have revealed that α-lipoic acid reduced MMP-9 mRNA expression in PC3 cells compared to the control (p < 0.05). In conclusion, this study highlights that α-lipoic acid induced apoptosis in human PC3 prostate cancer cells and inhibited the MMP-9 gene at the mRNA level, which is known to play a role in metastasis development.

Knockdown of heat shock protein family D member 1 (HSPD1) promotes proliferation and migration of ovarian cancer cells via disrupting the stability of mitochondrial 3-oxoacyl-ACP synthase (OXSM)

BACKGROUND

Heat shock protein 60 (HSP60) is essential for the folding and assembly of newly imported proteins to the mitochondria. HSP60 is overexpressed in most types of cancer, but its association with ovarian cancer is still in dispute. SKOV3 and OVCAR3 were used as experimental models after comparing the expression level of mitochondrial HSP60 in a normal human ovarian epithelial cell line and four ovarian cancer cell lines.

RESULTS

Low HSPD1 (Heat Shock Protein Family D (HSP60) Member 1) expression was associated with unfavorable prognosis in ovarian cancer patients. Knockdown of HSPD1 significantly promoted the proliferation and migration of ovarian cancer cells. The differentially expressed proteins after HSPD1 knockdown were enriched in the lipoic acid (LA) biosynthesis and metabolism pathway, in which mitochondrial 3-oxoacyl-ACP synthase (OXSM) was the most downregulated protein and responsible for lipoic acid synthesis. HSP60 interacted with OXSM and overexpression of OXSM or LA treatment could reverse proliferation promotion mediated by HSPD1 knockdown.

CONCLUSIONS

HSP60 interacted with OXSM and maintained its stability. Knockdown of HSPD1 could promote the proliferation and migration of SKOV3 and OVCAR3 via lowering the protein level of OXSM and LA synthesis.

Molecular and Therapeutic Insights of Alpha-Lipoic Acid as a Potential Molecule for Disease Prevention

Alpha-lipoic acid is an organic, sulfate-based compound produced by plants, humans, and animals. As a potent antioxidant and a natural dithiol compound, it performs a crucial role in mitochondrial bioenergetic reactions. A healthy human body, on the other hand, can synthesize enough α-lipoic acid to scavenge reactive oxygen species and increase endogenous antioxidants; however, the amount of α-lipoic acid inside the body decreases significantly with age, resulting in endothelial dysfunction. Molecular orbital energy and spin density analysis indicate that the sulfhydryl (-SH) group of molecules has the greatest electron donating activity, which would be responsible for the antioxidant potential and free radical scavenging activity. α-Lipoic acid acts as a chelating agent for metal ions, a quenching agent for reactive oxygen species, and a reducing agent for the oxidized form of glutathione and vitamins C and E. α-Lipoic acid enantiomers and its reduced form have antioxidant, cognitive, cardiovascular, detoxifying, anti-aging, dietary supplement, anti-cancer, neuroprotective, antimicrobial, and anti-inflammatory properties. α-Lipoic acid has cytotoxic and antiproliferative effects on several cancers, including polycystic ovarian syndrome. It also has usefulness in the context of female and male infertility. Although α-lipoic acid has numerous clinical applications, the majority of them stem from its antioxidant properties; however, its bioavailability in its pure form is low (approximately 30%). However, nanoformulations have shown promise in this regard. The proton affinity and electron donating activity, as a redox-active agent, would be responsible for the antioxidant potential and free radical scavenging activity of the molecule. This review discusses the most recent clinical data on α-lipoic acid in the prevention, management, and treatment of a variety of diseases, including coronavirus disease 2019. Based on current evidence, the preclinical and clinical potential of this molecule is discussed.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00370-1.

Dietary Antioxidant-Constructed Nanodrugs Can High-Efficiently Kill Cancer Cells while Protecting Noncancer Cells

Despite great advances, the development of cancer drugs that can efficiently kill cancer cells while protecting noncancer cells has not been achieved. By using only dietary antioxidants vitamin C (VC) and (R)-(+)-lipoic acid (LA), we herein develop a nanodrug VC@cLAV featuring the above function. After entering cells, cLAV dissociates into LA and DHLA (dihydrolipoic acid, reduced form of LA) and releases VC and DHA (dehydroascorbate, oxidized form of VC). In cancer cells, the two redox pairs recycle each other and dramatically promote the intracellular reactive oxygen species production to kill cancer cells at low doses comparable to cytotoxic drugs. Oppositely in noncancer cells, the LA/DHLA and VC/DHA pairs exert anti-oxidant action to actively protect the organism by preventing the normal cells from oxidative stress and repairing cells suffering from oxidative stress. When compared with the first-line cytotoxic drug, VC@cLAV displayed superior therapeutic outcomes yet without side effects in diverse tumor models including patient-derived xenograft (PDX). This drug with efficient cancer cell killing and noncancer cell protection represents a new cancer therapy.

Protective Effects of Alpha-Lipoic Acid against 5-Fluorouracil-Induced Gastrointestinal Mucositis in Rats

Alpha-lipoic acid (ALA) is extensively utilized in multivitamin formulas and anti-aging products. The purpose of this study was to investigate the potential protective benefits of ALA on 5-fluorouracil (5-FU)-induced gastrointestinal mucositis in Wistar albino rats. Tissues from the stomach, small intestine, and large intestine were excised, and blood sera were obtained to identify biochemical indices such as TNF-α, IL-1β, MDA, GPx, SOD, MMP-1, -2, -8, and TIMP-1. A histopathological study was also performed. The results revealed mucositis-elevated TNF-, IL-1, MDA, MMP-1, -2, -8, and TIMP-1 levels in both tissues and sera, and these values dropped dramatically following ALA treatment. Reduced SOD and GPx activities in mucositis groups were reversed in ALA-treated groups. The damage produced by mucositis in the stomach and small intestine regressed in the ALA-treated group, according to histopathological evaluation. Consequently, the implementation of ALA supplementation in 5-FU therapy may act as a protective intervention for cancer patients with gastrointestinal mucositis. In light of the findings, ALA, a food-derived antioxidant with pleiotropic properties, may be an effective treatment for 5-FU-induced gastrointestinal mucositus, and prevent oxidative stress, inflammation, and tissue damage in cancer patients receiving 5-FU therapy.

Culture of preantral ovarian follicles of Bos taurus indicus with alpha-lipoic acid

The aim of this study was to evaluate follicular development, morphological integrity, and antioxidant potential of preantral ovarian follicles from Bos taurus indicus females grown in vitro with alpha-lipoic acid. Ovaries (n = 24) of Bos taurus indicus (n = 12) females were collected during slaughter and fragmented. A randomly obtained fragment from each pair of ovaries was fixed in Bouin (non-cultivated control; D0). These fragments were intended for classical histology (morphology and evaluation of follicular growth), and a fragment from each pair of ovaries was frozen at -80°C (non-cultivated control; D0), and assigned for analysis of oxidative stress [thiobarbituric acid reactive substances (TBARS), nitroblue tetrazolium (NBT), and ferric reducing antioxidant power (FRAP)]. The remaining fragments were cultured in vitro for 6 (D6) or 12 (D12) days, containing only minimum essential medium (MEM) or MEM supplemented with alpha-lipoic acid (50, 100, or 250 ng/ml), on an extracellular matrix of agarose gel, in an oven at 38.5ºC. Every 2 days, 100% of the culture medium was replaced. Supplementation with 100 ng/ml was effective for maintaining follicular integrity after 6 days of culture (primordial: 51.28%; development: 36.88%; P < 0.0001). There was no difference (P > 0.05) between treatments compared with the non-cultivated control treatment (D0), using the NBT and TBARS assays. Therefore, supplementation of the in vitro culture medium of bovine preantral ovarian follicles with a concentration of 100 ng/ml of alpha-lipoic acid at 6 days of culture was effective for maintaining follicular integrity and, after 6 days, maintaining stable levels of reactive oxygen species.

Vincamine, a safe natural alkaloid, represents a novel anticancer agent

Vincamine, a well-known plant alkaloid, has been used as a dietary supplement and as a peripheral vasodilator to combat aging in humans. In this study, for the very first time, we demonstrated that vincamine can function as an anticancer agent in a human alveolar basal epithelial cell line A549 (IC₅₀ = 309.7 μM). The anticancer potential of vincamine in A549 cells was assessed by molecular assays to determine cell viability, generation of intracellular ROS, nuclear condensation, caspase-3 activity and inhibition, and change in mitochondrial membrane potential (ΔΨm). In silico studies predicted that the anti-proliferative potential of vincamine is enhanced by its interaction with the apoptotic protein caspase-3, and that this interaction is driven by two hydrogen bonds and has a high free energy of binding (-5.64 kcal/mol) with an estimated association constant (K_a) of 73.67 μM. We found that vincamine stimulated caspase-3-dependent apoptosis and lowered mitochondrial membrane potential, which ultimately led to cytochrome C release. Vincamine was also found to quench hydroxyl free radicals and deplete iron ions in cancer cells. As a dietary supplement, vincamine is almost non-toxic in BEAS-2B and 3T3-L1 cells. Therefore, we propose that vincamine represents a safe anticancer agent in lung cancer cells. Its role in other cancers has yet to be explored.

Targeting Altered Energy Metabolism in Colorectal Cancer: Oncogenic Reprogramming, the Central Role of the TCA Cycle and Therapeutic Opportunities

Colorectal cancer (CRC) is among the most frequent cancer entities worldwide. Multiple factors are causally associated with CRC development, such as genetic and epigenetic alterations, inflammatory bowel disease, lifestyle and dietary factors. During malignant transformation, the cellular energy metabolism is reprogrammed in order to promote cancer cell growth and proliferation. In this review, we first describe the main alterations of the energy metabolism found in CRC, revealing the critical impact of oncogenic signaling and driver mutations in key metabolic enzymes. Then, the central role of mitochondria and the tricarboxylic acid (TCA) cycle in this process is highlighted, also considering the metabolic crosstalk between tumor and stromal cells in the tumor microenvironment. The identified cancer-specific metabolic transformations provided new therapeutic targets for the development of small molecule inhibitors. Promising agents are in clinical trials and are directed against enzymes of the TCA cycle, including isocitrate dehydrogenase, pyruvate dehydrogenase kinase, pyruvate dehydrogenase complex (PDC) and α-ketoglutarate dehydrogenase (KGDH). Finally, we focus on the α-lipoic acid derivative CPI-613, an inhibitor of both PDC and KGDH, and delineate its anti-tumor effects for targeted therapy.

CPI-613 rewires lipid metabolism to enhance pancreatic cancer apoptosis via the AMPK-ACC signaling

BACKGROUND

Pancreatic cancer remains one of the most rapidly progressive and deadly malignancies worldwide. Current treatment regimens only result in small improvements in overall survival for patients with this cancer type. CPI-613 (Devimistat), a novel lipoate analog inhibiting mitochondrial metabolism, shows the new hope for pancreatic cancer treatment as an efficient and well-tolerated therapeutic option treated alone or in combination with chemotherapy.

METHODS

Pancreatic cancer cells growing in planar 2D cultures and 3D scaffold were used as research platforms. Cell viability was measured by MTT and alamarBlue, and apoptosis was assessed by JC-1 staining and flow cytometry with Annexin V-FITC/PI staining. The mechanism behind CPI-613 action was analyzed by western blot, transmission electron microscopy, and lipolysis assay kits, in the presence or absence of additional signaling pathway inhibitors or gene modifications.

RESULTS

CPI-613 exhibits anticancer activity in pancreatic cancer cells by triggering ROS-associated apoptosis, which is accompanied by increased autophagy and repressed lipid metabolism through activating the AMPK signaling. Intriguingly, ACC, the key enzyme modulating lipid metabolism, is identified as a vital target of CPI-613, which is inactivated in an AMPK-dependent manner and influences apoptotic process upon CPI-613. Blockade or enhancement of autophagic process does not increase or blunt apoptosis to CPI-613, but inhibition of the AMPK-ACC signaling significantly attenuates apoptosis induced by CPI-613, suggesting CPI-613-mediated lipid metabolism reduction contributes to its cytotoxicity in pancreatic cancer cells.

CONCLUSIONS

These findings explore the critical role of lipid metabolism in apoptosis, providing new insights into the AMPK-ACC signaling axis in crosstalk between lipid metabolism and apoptosis in CPI-613 treatment.

Alpha-lipoic acid inhibits lung cancer growth via mTOR-mediated autophagy inhibition

Lung cancer is the leading cause of cancer‐related death, and there remains a need for novel therapies for this malignancy. Here, we examined the effects of alpha‐lipoic acid (LA), a drug used for treating human diabetic complications, on lung cancer growth. We report that LA limited lung cancer growth in xenograft mice and reduced lung cancer A549 cell viability. We observed autophagy activation in human lung cancers, and report that LA inactivated autophagy in A549 cells. In addition, LA activated mammalian target of rapamycin (mTOR)/p70S6K signaling. Inhibition of mTOR with rapamycin reversed LA‐induced inactivation of autophagy and abolished LA‐induced suppression of A549 cell viability. Altogether, the data suggest that LA exerts an anti‐lung cancer effect through mTOR‐mediated inhibition of autophagy, and thus LA may have therapeutic potential for lung cancer management.

Lipoic acid decreases breast cancer cell proliferation by inhibiting IGF-1R via furin downregulation

BACKGROUND

Breast cancer is the second most common cancer in the world. Despite advances in therapies, the mechanisms of resistance remain the underlying cause of morbidity and mortality. Lipoic acid (LA) is an antioxidant and essential cofactor in oxidative metabolism. Its potential therapeutic effects have been well documented, but its mechanisms of action (MOA) are not fully understood.

METHODS

The aim of this study is to validate the inhibitory LA effect on the proliferation of various breast cancer cell lines and to investigate the MOA that may be involved in this process. We tested LA effects by ex vivo studies on fresh human mammary tumour samples.

RESULTS

We demonstrate that LA inhibits the proliferation and Akt and ERK signalling pathways of several breast cancer cells. While searching for upstream dysregulations, we discovered the loss of expression of IGF-1R upon exposure to LA. This decrease is due to the downregulation of the convertase, furin, which is implicated in the maturation of IGF-1R. Moreover, ex vivo studies on human tumour samples showed that LA significantly decreases the expression of the proliferation marker Ki67.

CONCLUSION

LA exerts its anti-proliferative effect by inhibiting the maturation of IGF-1R via the downregulation of furin.

Lipoic acid-induced oxidative stress abrogates IGF-1R maturation by inhibiting the CREB/furin axis in breast cancer cell lines

The beneficial effects of lipoic acid (LA) in cancer treatment have been well documented in the last decade. Indeed, LA exerts crucial antiproliferative effects by reducing breast cancer cell viability, cell cycle progression and the epithelial-to-mesenchymal transition (EMT). However, the mechanisms of action (MOA) underlying these antiproliferative effects remain to be elucidated. Recently, we demonstrated that LA decreases breast cancer cell proliferation by inhibiting IGF-1R maturation via the downregulation of the proprotein convertase furin. The aim of the present study was to investigate the MOA by which LA inhibits furin expression in estrogen receptor α (ERα) (+) and (-) breast cancer cell lines. We unveil that LA exerts a pro-oxidant effect on these cell lines, the resulting reactive oxygen species (ROS) generated being responsible for the reduction in the expression of the major (CREB) protein. This transcription factor is overexpressed in many types of cancers and regulates the expression of furin in breast cancer cells independently of ERα, as evidenced herein by the inhibition of furin expression following CREB silencing. Consequently, our findings expose for the first time the complete MOA of LA via the CREB/furin axis leading to inhibition of breast cancer cell proliferation.

Insights on the Use of α-Lipoic Acid for Therapeutic Purposes

α-lipoic acid (ALA, thioctic acid) is an organosulfur component produced from plants, animals, and humans. It has various properties, among them great antioxidant potential and is widely used as a racemic drug for diabetic polyneuropathy-associated pain and paresthesia. Naturally, ALA is located in mitochondria, where it is used as a cofactor for pyruvate dehydrogenase (PDH) and α-ketoglutarate dehydrogenase complexes. Despite its various potentials, ALA therapeutic efficacy is relatively low due to its pharmacokinetic profile. Data suggests that ALA has a short half-life and bioavailability (about 30%) triggered by its hepatic degradation, reduced solubility as well as instability in the stomach. However, the use of various innovative formulations has greatly improved ALA bioavailability. The R enantiomer of ALA shows better pharmacokinetic parameters, including increased bioavailability as compared to its S enantiomer. Indeed, the use of amphiphilic matrices has capability to improve ALA bioavailability and intestinal absorption. Also, ALA's liquid formulations are associated with greater plasma concentration and bioavailability as compared to its solidified dosage form. Thus, improved formulations can increase both ALA absorption and bioavailability, leading to a raise in therapeutic efficacy. Interestingly, ALA bioavailability will be dependent on age, while no difference has been found for gender. The present review aims to provide an updated on studies from preclinical to clinical trials assessing ALA's usages in diabetic patients with neuropathy, obesity, central nervous system-related diseases and abnormalities in pregnancy.

Lipoic Acid Synergizes with Antineoplastic Drugs in Colorectal Cancer by Targeting p53 for Proteasomal Degradation

Lipoic acid (LA) is a redox-active disulphide compound, which functions as a pivotal co-factor for mitochondrial oxidative decarboxylation. LA and chemical derivatives were shown to target mitochondria in cancer cells with altered energy metabolism, thereby inducing cell death. In this study, the impact of LA on the tumor suppressor protein p53 was analyzed in various colorectal cancer (CRC) cell lines, with a focus on the mechanisms driving p53 degradation. First, LA was demonstrated to trigger the depletion of both wildtype and mutant p53 protein in all CRC cells tested without influencing its gene expression and preceded LA-triggered cytotoxicity. Depletion of p53 coincided with a moderate, LA-dependent ROS production, but was not rescued by antioxidant treatment. LA induced the autophagy receptor p62 and differentially modulated autophagosome formation in CRC cells. However, p53 degradation was not mediated via autophagy as shown by chemical inhibition and genetic abrogation of autophagy. LA treatment also stabilized and activated the transcription factor Nrf2 in CRC cells, which was however dispensable for p53 degradation. Mechanistically, p53 was found to be readily ubiquitinylated and degraded by the proteasomal machinery following LA treatment, which did not involve the E3 ubiquitin ligase MDM2. Intriguingly, the combination of LA and anticancer drugs (doxorubicin, 5-fluorouracil) attenuated p53-mediated stabilization of p21 and resulted in synergistic killing in CRC cells in a p53-dependant manner.

Role of coenzymes in cancer metabolism

Cancer is a heterogeneous set of diseases characterized by the rewiring of cellular signaling and the reprogramming of metabolic pathways to sustain growth and proliferation. In past decades, studies were focused primarily on the genetic complexity of cancer. Recently, increasing number of studies have discovered several mutations among metabolic enzymes in different tumor cells. Most of the enzymes are regulated by coenzymes, organic cofactors, that function as intermediate carrier of electrons or functional groups that are transferred during the reaction. However, the precise role of cofactors is not well elucidated. In this review, we discuss several metabolic enzymes associated to cancer metabolism rewiring, whose inhibition may represent a therapeutic target. Such enzymes, upon expression or inhibition, may impact also the coenzymes levels, but only in few cases, it was possible to direct correlate coenzymes changes with a specific enzyme. In addition, we also summarize an up-to-date information on biological role of some coenzymes, preclinical and clinical studies, that have been carried out in various cancers and their outputs.

Biogenic pentagonal silver nanoparticles for safer and more effective antibacterial therapeutics

Background

Biological synthesis of nanomaterials possesses unprecedented potential in the production of nanomaterials due to their ability to produce nanomaterials with improved biocompatibility in addition to eco-friendly synthetic procedures.

Methods

This article reports the isolation of an air-borne fungus from the campus of Integral University, Lucknow, with an exceptional ability to withstand very high concentrations of silver salt. The fungus was found to produce pentagonal silver nanoparticles (AgPgNps) when silver ions were reduced from silver nitrate. Molecular analysis and biochemical characterization techniques based on 18-seconds rRNA identified the fungus to belong to the Aspergillus sp. with the NCBI accession no KF913249. Material characterization techniques including ultraviolet (UV)–visible spectroscopy, transmission electron microscopy, and zeta potential analysis were used to satisfactorily characterize the as-synthesized AgPgNps.

Results

The AgPgNps synthesized by the fungus Aspergillus sp. exhibit an absorption that is maximum centered at about 416 nm, with a standard particle size of 23.22±2 nm. These AgPgNps exhibited broad-spectrum antimicrobial activities against an array of bacterial pathogens with remarkable minimum inhibitory concentration (MIC₅₀) values: Staphylococcus aureus (ATCC 25923) – 9.230 µg/mL, Bacillus sp. (ATCC 14593) – 12.781 µg/mL, Escherichia coli (ATCC 25922) – 5.063 µg/mL, and Klebsiella pneumoniae (ATCC 13883) – 5.426 µg/mL. In vitro cytotoxicity analysis of biosynthesized AgPgNps showed a dose–response activity against human cervical cancer cell line (HeLa) and adenocarcinoma cells (A549) with MIC₅₀ values of 0.038 µg/mL and 0.044 µg/mL, respectively.

Conclusion

These findings are very crucial to evaluate the biosynthetic process for the synthesis of nanoparticles (NPs) with unique properties. These NPs may find potential applications in sensing, medicine, and antimicrobial and anticancer therapies.

Pathophysiology and aetiology of hypoglycaemic crises

Hypoglycaemia is a common, life-threatening complication that occurs as a component of a wide variety of disease processes. Despite its frequent occurrence, information concerning the aetiology, characteristics and outcomes of hypoglycaemic crises in veterinary medicine is limited. This review summarises the current understanding of the pathophysiology of hypoglycaemia, the body's counter-regulatory response, underlying aetiologies, diagnosis and treatment. Disease mechanisms are discussed and published evidence in veterinary literature regarding prognostic indicators, prevalence, diagnosis and treatment is examined for hypoglycaemia-related disease processes including insulinoma, glucose-lowering toxins and medications.

Multi-Acting Mitochondria-Targeted Platinum(IV) Prodrugs of Kiteplatin with α-Lipoic Acid in the Axial Positions

Platinum(II) drugs are activated intracellularly by aquation of the leaving groups and then bind to DNA, forming DNA adducts capable to activate various signal-transduction pathways. Mostly explored in recent years are Pt(IV) complexes which allow the presence of two additional ligands in the axial positions suitable for the attachment of other cancer-targeting ligands. Here we have extended this strategy by coordinating in the axial positions of kiteplatin ([PtCl₂(cis-1,4-DACH)], DACH = Diaminocyclohexane) and its CBDCA (1,1-cyclobutanedicarboxylate) analogue the antioxidant α-Lipoic acid (ALA), an inhibitor of the mitochondrial pyruvate dehydrogenase kinase (PDK). The new compounds (cis,trans,cis-[Pt(CBDCA)(ALA)₂(cis-1,4-DACH)], 2, and cis,trans,cis-[PtCl₂(ALA)₂(cis-1,4-DACH)], 3), after intracellular reduction, release the precursor Pt(II) species and two molecules of ALA. The Pt residue is able to target DNA, while ALA could act on mitochondria as activator of the pyruvate dehydrogenase complex, thus suppressing anaerobic glycolysis. Compounds 2 and 3 were tested in vitro on a panel of five human cancer cell lines and compared to cisplatin, oxaliplatin, and kiteplatin. They proved to be much more effective than the reference compounds, with complex 3 most effective in 3D spheroid tumor cultures. Notably, treatment of human A431 carcinoma cells with 2 and 3 did not determine increase of cellular ROS (usually correlated to inhibition of mitochondrial PDK) and did not induce a significant depolarization of the mitochondrial membrane or alteration of other morphological mitochondrial parameters.

Andrographolide Exhibits Anticancer Potential Against Human Colon Cancer Cells by Inducing Cell Cycle Arrest and Programmed Cell Death via Augmentation of Intracellular Reactive Oxygen Species Level

Andrographolide, a diterpenoid lactone and a major constituent of Andrographis paniculata Nees, exhibits remarkable anticancer activity. However, the effect of andrographolide on colon cancer has not been completely elucidated yet. Thus, we investigated the chemopreventive potential of andrographolide in colon cancer HT-29 cells. The cytotoxic potential of andrographolide on HT-29 cells was determined by MTT assay, trypan blue exclusion assay, colony formation assay, and morphological analysis; and apoptotic property by DAPI and Hoechst staining, FITC-Annexin V assay, DNA fragmentation assay and caspase-3 activity assay. To elucidate andrographolide action, intracellular reactive oxygen species (ROS) level was determined by DCFDA dye; change in mitochondrial potential by Rhodamine123 and Mito Tracker Red CMXRos dye; and cell cycle modulatory property by flow cytometric analysis. Results of the study have shown that andrographolide decreased cell viability of HT-29 cells in a dose- and time-dependent manner. Furthermore, andrographolide induced apoptosis in HT-29 cells which seemed to be linked with augmented intracellular ROS level and disruption of mitochondrial membrane potential. Interestingly, andrographolide caused significant cell cycle arrest in G2/M phase at lower doses, but, in G0/G1 phase at higher doses. In summary, our results indicated that andrographolide exhibited antiproliferative and apoptotic properties against colon cancer HT-29 cells.

Focused Review: Cytotoxic and Antioxidant Potentials of Mangrove-Derived Streptomyces

Human life expectancy is rapidly increasing with an associated increasing burden of chronic diseases, such as neurodegenerative diseases and cancer. However, there is limited progress in finding effective treatment for these conditions. For this reason, members of the genus Streptomyces have been explored extensively over the past decades as these filamentous bacteria are highly efficient in producing bioactive compounds with human health benefits. Being ubiquitous in nature, streptomycetes can be found in both terrestrial and marine environments. Previously, two Streptomyces strains (MUSC 137T and MUM 256) isolated from mangrove sediments in Peninsular Malaysia demonstrated potent antioxidant and cytotoxic activities against several human cancer cell lines on bioactivity screening. These results illustrate the importance of streptomycetes from underexplored regions aside from the terrestrial ecosystem. Here we provide the insights and significance of Streptomyces species in the search of anticancer and/or chemopreventive agents and highlight the impact of next generation sequencing on drug discovery from the Streptomyces arsenal.

Suppression of a cancer stem-like phenotype mediated by alpha-lipoic acid in human lung cancer cells through down-regulation of β-catenin and Oct-4

PURPOSE

Cancer stem cells (CSCs) that possess the ability of self-renewal and multi-potency have been shown to drive tumor progression and metastasis. The majority of recent studies has focused on potential molecules targeting CSCs so as to develop novel strategies for efficient cancer treatment or protection. Here, we show how alpha-lipoic acid (LA), an endogenous mitochondrial anti-oxidant, affects the CSC-like phenotypes of human non-small cell lung cancer-derived H23, H292 and H460 cells.

METHODS

CSC-like phenotypes were verified by anchorage-independent growth, three-dimensional (3D) spheroid formation and the expression of CSC markers. Enriched CSC populations were used to confirm the effects of LA. Protein ubiquitination and degradation were assessed using immunoprecipitation.

RESULTS

We found that treatment with LA reduced the CSC-like phenotype, as indicated by a decreased expression of known CSC markers (CD133, CD44, ALDH1A1, Oct-4 and Nanog) in H460 cells. In addition, we found that LA reduced the CSC-related abilities of anchorage-independent growth and 3D spheroid formation, and suppressed factors related to epithelial-mesenchymal transition, such as E-cadherin, Vimentin, Slug and Snail. Mechanistically, we found that LA suppresses CSC through depletion of the cellular stemness proteins β-catenin and Oct-4 via decreasing the level of active (phosphorylated) Akt. This resulted in the induction of GSK3β-dependent β-catenin ubiquitin-proteasomal degradation and a decrease in the stabilized (phosphorylated) form of Oct-4. The effects of LA on the CSC-like phenotypes were confirmed in CSC enriched H460, H292 and H23 non-small cell lung cancer-derived cells.

CONCLUSION

Our data are indicative for a novel regulatory role and underlying mechanism of LA in the negative regulation of a CSC-like phenotype in non-small cell lung cancer-derived cells.

Protective role of α-lipoic acid in hyperuricemia-induced endothelial dysfunction

The aim of the current study was to determine the effects of α-lipoic acid (LA) on hyperuricemia and endothelial dysfunction, and to uncover the underlying mechanism of its action. A hyperuricemic rat model was established by administration of uric acid (UA) and the rats were orally fed with 2 g/kg/day LA or phosphate-buffered saline. Primary rat aortic endothelial cells were subsequently isolated, and a cell viability assay, apoptosis assay, enzyme nitric oxide synthase (eNOS) activity assay and mitochondrial function assay were all performed. For the in vitro study, human umbilical vein endothelial cells were used and western blotting was performed to assess Akt signaling activity. The results of the current study indicated that LA inhibited apoptosis, enhanced eNOS activity and production of nitric oxide (NO), and rescued mitochondrial mass and function in uric acid (UA)-treated endothelial cells. LA activated Akt signaling and inhibition of Akt signaling abolished the effects of LA on cell viability, NO production, ROS production and ATP levels in UA-treated endothelial cells. Therefore, the current study demonstrated that LA attenuated oxidant stress and inhibited apoptosis in UA-treated endothelial cells by activating Akt signaling. The results indicate that LA may serve as a therapeutic approach to treat hyperuricemia-induced endothelial dysfunction.

Time Course Effect of R-Alpha-Lipoic Acid on Cellular Metabolomics in Cultured Hepatoma Cells

Alpha-lipoic acid (LA) is a powerful antioxidant. LA has two enantiomers, R(+)-LA (R-LA) and S(-)-LA (S-LA). Of these, R-LA is naturally occurring and an essential cofactor in energy metabolism. R-LA treatment has been reported to affect glucose metabolism in rat hepatoma cells. This study analyzed the time course of metabolite levels in LA-treated cultured H4IIEC3 rat hepatoma cells, including a specific evaluation of the effect of R-LA and the enantioselectivity of LA. Principal component analysis showed that this experiment was well designed to observe enantioselectivity. R-LA treatment was found to inhibit the glycolysis and Thr-Gly-Ser pathways, as well as lactic acid production, leading to the inhibition of gluconeogenesis in starved H4IIEC3 cells. This study may provide mechanistic insight into how R-LA induces apoptosis in hepatoma cells.

Mixed micelles of lipoic acid-chitosan-poly(ethylene glycol) and distearoylphosphatidylethanolamine-poly(ethylene glycol) for tumor delivery

Many chemotherapeutics suffer from poor aqueous solubility and tissue selectivity. Distearoylphosphatidylethanolamine-poly(ethylene glycol) (DSPE-PEG) micelles are a promising formulation strategy for the delivery of hydrophobic anticancer drugs. However, storage and in vivo instability restrict their use. The aim of this study was to prepare mixed micelles, containing a novel polymer, lipoic acid-chitosan-poly(ethylene glycol) (LACPEG), and DSPE-PEG, to overcome these limitations and potentially increase cancer cell internalisation. Drug-loaded micelles were prepared with a model tyrosine kinase inhibitor and characterized for size, surface charge, stability, morphology, drug entrapment efficiency, cell viability (A549 and PC-9 cell lines), in vivo biodistribution, ex vivo tumor accumulation and cellular internalisation. Micelles of size 30-130nm with entrapment efficiencies of 46-81% were prepared. LACPEG/DSPE-PEG mixed micelles showed greater interaction with the drug (condensing to half their size following entrapment), greater stability, and a safer profile in vitro compared to DSPE-PEG micelles. LACPEG/DSPE-PEG and DSPE-PEG micelles had similar entrapment efficiencies and in vivo tumor accumulation levels, but LACPEG/DSPE-PEG micelles showed higher tumor cell internalisation. Collectively, these findings suggest that LACPEG/DSPE-PEG mixed micelles provide a promising platform for tumor delivery of hydrophobic drugs.

Out of Warburg effect: An effective cancer treatment targeting the tumor specific metabolism and dysregulated pH

As stated by Otto Warburg nearly a century ago, cancer is a metabolic disease, a fermentation caused by malfunctioning mitochondria, resulting in increased anabolism and decreased catabolism. Treatment should, therefore, aim at restoring the energy yield. To decrease anabolism, glucose uptake should be reduced (ketogenic diet). To increase catabolism, the oxidative phosphorylation should be restored. Treatment with a combination of α-lipoic acid and hydroxycitrate has been shown to be effective in multiple animal models. This treatment, in combination with conventional chemotherapy, has yielded extremely encouraging results in glioblastoma, brain metastasis and lung cancer. Randomized trials are necessary to confirm these preliminary data. The major limitation is the fact that the combination of α-lipoic acid and hydroxycitrate can only be effective if the mitochondria are still present and/or functional. That may not be the case in the most aggressive tumors. The increased intracellular alkalosis is a strong mitogenic signal, which bypasses most inhibitory signals. Concomitant correction of this alkalosis may be a very effective treatment in case of mitochondrial failure.

The Long-term Survival of a Patient With Pancreatic Cancer With Metastases to the Liver After Treatment With the Intravenous α-Lipoic Acid/Low-Dose Naltrexone Protocol

The authors describe the long-term survival of a patient with pancreatic cancer without any toxic adverse effects. The treatment regimen includes the intravenous α-lipoic acid and low-dose naltrexone (ALA-N) protocol and a healthy lifestyle program. The patient was told by a reputable university oncology center in October 2002 that there was little hope for his survival. Today, January 2006, however, he is back at work, free from symptoms, and without appreciable progression of his malignancy. The integrative protocol described in this article may have the possibility of extending the life of a patient who would be customarily considered to be terminal. The authors believe that life scientists will one day develop a cure for metastatic pancreatic cancer, perhaps via gene therapy or another biological platform. But until such protocols come to market, the ALA-N protocol should be studied and considered, given its lack of toxicity at levels reported. Several other patients are on this treatment protocol and appear to be doing well at this time.

α-Lipoic acid sensitizes lung cancer cells to chemotherapeutic agents and anoikis via integrin β1/β3 downregulation

Chemotherapeutic failure and metastasis are the main causes of high mortality rate in lung cancer. Alteration of cellular redox status in response to endogenous stimuli or exogenous compounds has a significant impact on cell signaling and behavior. Herein we divulge for the first time that lung cancer cells exposed to α-lipoic acid (LA) resulted in a higher level of cellular superoxide anion (O2·-) and hydrogen peroxide (H2O2), and such an increase of the specific reactive oxygen species (ROS) downregulated integrin β1 and β3, the integrins known for potentiating aggressive behavior and metastasis. The LA-treated cells exhibited significant decrease in their abilities to survive in detached condition and grow in anchorage-independent soft agar assay. Furthermore, LA sensitized the cells to cisplatin, etoposide and paclitaxel-induced apoptosis. For underlying mechanism, we found that the treatment of the cells with LA significantly decreased integrin β1 and β3, while had no effect on integrin α5 and αv. Interestingly, survival protein p-AKT and anti-apoptotic protein Bcl-2 were reduced in an association to such integrin modulations. Using ROS probes and selective anti-oxidants, we have shown that H2O2 and O2·- induced by LA are key players for the decrease of β1 and β3 integrins, respectively. These findings indicate a novel effect of LA as well as specific ROS, O2·- and H2O2 in integrin regulation, anoikis and chemotherapeutic sensitizations.

The disulfide compound α-lipoic acid and its derivatives: A novel class of anticancer agents targeting mitochondria

The endogenous disulfide α-lipoic acid (LA) is an essential mitochondrial co-factor. In addition, LA and its reduced counterpart dihydro lipoic acid form a potent redox couple with antioxidative functions, for which it is used as dietary supplement and therapeutic. Recently, it has gained attention due to its cytotoxic effects in cancer cells, which is the key aspect of this review. We initially recapitulate the dietary occurrence, gastrointestinal absorption and pharmacokinetics of LA, illustrating its diverse antioxidative mechanisms. We then focus on its mode of action in cancer cells, in which it triggers primarily the mitochondrial pathway of apoptosis, whereas non-transformed primary cells are hardly affected. Furthermore, LA impairs oncogenic signaling and displays anti-metastatic potential. Novel LA derivatives such as CPI-613, which target mitochondrial energy metabolism, are described and recent pre-clinical studies are presented, which demonstrate that LA and its derivatives exert antitumor activity in vivo. Finally, we highlight clinical studies currently performed with the LA analog CPI-613. In summary, LA and its derivatives are promising candidates to complement the arsenal of established anticancer drugs due to their mitochondria-targeted mode of action and non-genotoxic properties.

Apoptotic Cell Death Induced by Resveratrol Is Partially Mediated by the Autophagy Pathway in Human Ovarian Cancer Cells

Resveratrol (trans-3,4,5’ –trihydroxystilbene) is an active compound in food, such as red grapes, peanuts, and berries. Resveratrol exhibits an anticancer effect on various human cancer cells. However, the mechanism of resveratrol-induced anti-cancer effect at the molecular level remains to be elucidated. In this study, the mechanism underlying the anti-cancer effect of resveratrol in human ovarian cancer cells (OVCAR-3 and Caov-3) was investigated using various molecular biology techniques, such as flow cytometry, western blotting, and RNA interference, with a major focus on the potential role of autophagy in resveratrol-induced apoptotic cell death. We demonstrated that resveratrol induced reactive oxygen species (ROS) generation, which triggers autophagy and subsequent apoptotic cell death. Resveratrol induced ATG5 expression and promoted LC3 cleavage. The apoptotic cell death induced by resveratrol was attenuated by both pharmacological and genetic inhibition of autophagy. The autophagy inhibitor chloroquine, which functions at the late stage of autophagy, significantly reduced resveratrol-induced cell death and caspase 3 activity in human ovarian cancer cells. We also demonstrated that targeting ATG5 by siRNA also suppressed resveratrol-induced apoptotic cell death. Thus, we concluded that a common pathway between autophagy and apoptosis exists in resveratrol-induced cell death in OVCAR-3 human ovarian cancer cells.

Lipoic acid induces p53-independent cell death in colorectal cancer cells and potentiates the cytotoxicity of 5-fluorouracil

Alpha-lipoic acid (LA), which plays a pivotal role in mitochondrial energy metabolism, is an endogenous dithiol compound with an array of antioxidative functions. It has been shown that LA triggers cell death in tumor cell lines, whereas non-transformed cells are hardly affected. In the present study, we analyzed the cytotoxicity of LA on colorectal cancer (CRC) cells differing in their p53 status and investigated a putative synergistic effect with the anticancer drug 5-fluorouracil (5-FU). We show that LA induces a dose-dependent decrease in cell viability, which was independent of the p53 status as attested in isogenic p53-proficient and p53-deficient cell lines. This effect was largely attributable to cell death induction as revealed by Annexin-V/PI staining. LA-treated HCT116 cells underwent caspase-dependent and caspase-independent cell death, which was blocked by the pan-caspase inhibitor zVAD and the RIP-kinase inhibitor Necrostatin-1, respectively. In CaCO-2 and HT29 cells, LA induced caspase-dependent cell demise via activation of caspase-9, caspase-3 and caspase-7 with subsequent PARP-1 cleavage as demonstrated by immunoblot analysis, activity assays and pan-caspase inhibition. Interestingly, LA treatment did neither activate p53 nor induced genotoxic effects as shown by lack of DNA strand breaks and phosphorylation of histone 2AX. Finally, we provide evidence that LA increases the cytotoxic effect induced by the anticancer drug 5-FU as revealed by significantly enhanced cell death rates in HCT116 and CaCO-2 cells. Collectively, these findings demonstrate that LA induces CRC cell death independent of their p53 status and potentiates the cytotoxicity of 5-FU without causing DNA damage on its own, which makes it a candidate for tumor therapy.