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| Citric acid is the acid form, and citrate is the salt or conjugate base form. The two terms are often used interchangeably in casual conversation, but chemically they refer to different states depending on the pH of the environment. Citrate is a naturally occurring compound found in various forms in nature. It is a conjugate base of citric acid, a weak organic acid that is commonly found in citrus fruits, such as lemons and oranges. Citrate plays a crucial role in the production of energy in cells. It is a key intermediate in the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle), which is a series of chemical reactions that occur in the mitochondria of cells. Naturally found in citrus fruits and many other plants. Citric acid is a key metabolic intermediate in the tricarboxylic acid (TCA) cycle. • Citric acid is central to cellular energy metabolism as part of the TCA cycle. Changes in its concentration can affect the flux through the cycle and the overall cellular redox state. • Enhanced TCA activity may lead to increased production of reducing equivalents (NADH, FADH₂) and subsequent electron transport chain (ETC) activity. If the ETC becomes overloaded or dysfunctional, it can lead to electron leakage and increased ROS production. • Although citric acid itself is not a classical antioxidant, it can act as a chelating agent for certain metal ions. By binding transition metals (such as iron and copper), citrate can potentially reduce metal-catalyzed ROS formation. • This chelating property can indirectly protect cells from oxidative damage, especially under conditions where free metal ions might otherwise catalyze ROS-generating reactions. -Crucial role of citrate to supply the acetyl-CoA pool for fatty acid synthesis and histone acetylation in tumors -Citrate is a major product of mitochondria, the engine of the cell. -The more Citrate builds up in the cell, the more the cell will think it has enough of what it needs and will reduce or even shut down the glycolisis process. Citrate is produced inside the mitochondria within the Krebs cycle. When the cell has excess energy, citrate is transported out of the mitochondrial matrix across the inner membrane via the mitochondrial citrate transport protein (CTP). In the cytoplasm, is then broken down by the ACLY (ACL) enzyme into acetyl-CoA: for fatty acid synthesis and cholesterol production oxaloacetate: to be converted back to pyruvate and enter mitochondria again (might be desirable to inhibit ACYL with HCA) and maybe Statins. -May also synergize with Metformin? Sodium citrate is the sodium salt of citric acid, used as a buffer and food additive, while citric acid is a weak organic acid, naturally found in citrus fruits. Summary: -Citrate is considered to play a crucial role in cancer metabolism by virtue of its production in the reverse Krebs cycle from glutamine -Chelation of Ca2+ by sodium citrate resulted in inactivation of CAMKK2 and AMPK (inhibited the Ca2+/CAMKK2/AKT/mTOR signaling) -”promoter of cell proliferation (at lower concentrations) and as an anticancer agent (at higher concentrations)” -”ACLY, which has been found to be overexpressed in many cancers, converts citrate into acetyl-CoA and OAA.“ -”administration of citrate at high level mimics a strong inhibition of ACLY” (HCA is a known natural ACLY inhibitor) -Citrate is a well-known physiological inhibitor of PFK1. -Some reduction in Mcl-1 expression -May low ROS by decreasing oxygen consumption (ie not compatible with proxidant treatment?) -Deactivation of the NF-κB signaling ? -Lemons: 5–8% citric acid by weight -Limes: 4–7% citric acid. -Grapefruits: 2–5% in the juice -Oranges (and Tangerines/Mandarins): 1–2% in the juice Many commercially prepared beverages (like some soft drinks, citrus-based jams, and preserves) and sour candies have citric acid added as a flavoring agent or preservative. In these products, the citric acid concentration can sometimes be higher than that in the unprocessed fruit juice. Acid Reflux & Dental Health: Increasing citric acid, especially from highly concentrated sources (like pure citric acid or very sour juices), may exacerbate symptoms in individuals with acid reflux or cause enamel erosion on teeth. Drinking water after consuming citrus products or using a straw (when drinking acidic beverages) can help reduce the direct contact of acid with your teeth. • Low/Moderate Doses: In some models, low to moderate citrate supplementation can actually help cells maintain redox balance. • High Doses: At higher concentrations, citrate can overload certain metabolic pathways. An excess supply of citrate may drive the TCA cycle at a rate that overwhelms the electron transport chain, potentially increasing the leakage of electrons and therefore raising ROS production. • Cancer vs. Non-Cancer Cells: Cancer cells frequently have reprogrammed metabolism. In some cases, citrate supplementation in cancer cells can have different effects compared to healthy cells. For instance, due to the metabolic alterations in cancer cells, a high dose of citrate might exacerbate mitochondrial dysfunction, leading to higher ROS levels. Conversely, in a non-cancer context or cells with robust metabolic flexibility, the same dose might be better tolerated or even beneficial for redox balance. ROS: Antioxidant Role: • In some contexts, citrate can act as an antioxidant. It has the capacity to chelate metal ions (like iron and copper), which can catalyze ROS formation via reactions such as the Fenton reaction. • Moreover, as a key intermediate in the tricarboxylic acid (TCA) cycle, citrate contributes to cellular energy metabolism, which, when properly balanced, may help maintain homeostasis and limit excessive ROS production. Potential Pro-Oxidant Effects: • At high doses or under certain conditions, an overload of citrate might alter normal cellular metabolic pathways. For example, excess citrate can affect mitochondrial function and the TCA cycle’s balance, potentially leading to metabolic disturbances that contribute to increased ROS formation in some in vitro models or under pathological conditions. • In certain experimental settings, drastic changes in cellular intermediate concentrations can trigger compensatory mechanisms that might inadvertently lead to oxidative stress. Context Matters: • The net effect of high-dose citrate on ROS largely depends on the experimental model and the presence of additional factors (such as the concentration of available metal ions, the oxidative state of the cell, and the cell’s overall metabolic status). • In a well-regulated physiological environment, moderate levels of citrate may support antioxidant defenses, whereas in stress or disease states, high doses might tip the balance toward increased ROS production. -High doses of citric acid/citrate in cancer cells are generally associated with an increase in ROS due to metabolic and mitochondrial stress. However, because the effect is highly context-specific, the overall outcome may depend on multiple factors related to the cancer cell type and its existing metabolic state. (Note this statement might not be supported by research papers-but rather chat ai) DoseCitric acid: 4g-30g/day. 4g-8g/day most common? split 3-4 times/day? with meals
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| Citrate is a key metabolite involved in cellular energy metabolism, and its levels are often elevated cancer cells. -Citrate is a key substrate for the citric acid cycle (also known as the Krebs cycle or tricarboxylic acid cycle), which is involved in cellular energy metabolism. -Citrate is also involved in the regulation of glycolysis, which is the primary source of energy for many cancer cells. -Citrate has been shown to promote cancer cell growth and survival by regulating various signaling pathways, including the PI3K/AKT pathway. High citrate levels are often associated with poor prognosis in various cancers, including breast, lung, colorectal, prostate, pancreatic, ovarian, and glioblastoma. – Several studies have reported that in certain aggressive tumors, intracellular citrate levels tend to be lower relative to adjacent normal tissues. This is thought to be due to increased utilization of citrate for anabolic processes (e.g., fatty acid synthesis). It was found that the citrate levels of normal human prostate tissue are uniquely much higher than those in malignant prostate tissue (43.1 versus 19.9 mmol/kg). Furthermore, the drastic decrease of citrate level (up to 40-fold in early and 80-fold in advanced stages) in prostate cancer tissues in comparison to normal prostatic tissues is a key characteristic utilized to distinguish between normal and hyperplastic glands. In addition to prostate cancer, citrate levels are significantly decreased in blood of patients with lung, bladder, pancreas and esophagus cancers compared with healthy persons. As a consequence, normal prostate has high concentrations of citrate whereas prostate cancer has low concentrations of citrate. It was widely believed that cancer cells did not take up citrate from the circulation (blood levels of citrate, ~200 μM) and that they met their increased demands for this metabolite via de no synthesis from glutamine (Metallo et al., 2011). This requires a novel reprogramming of the metabolism involving the reversal of the Krebs cycle in which α-ketoglutarate arising from glutamine gets converted into citrate by a process known as “reductive carboxylation.” Indeed, uptake of glutamine resulting from increased expression of multiple glutamine transporters has been associated with cancer cells. Citrate is not only a metabolic intermediate but also a critical signaling node that affects epigenetic regulation (via acetyl-CoA), lipogenesis, and cellular survival pathways. The expression levels of ACLY, SLC25A1, IDH1/2, FASN, and SREBF1 have emerged as important prognostic biomarkers or therapeutic targets in various cancers. -Lower plasma citrate levels have been observed in some cancer patients, suggesting that the tumor’s high metabolic demand may deplete circulating citrate. While many tumors show reduced tissue citrate due to its rapid utilization in anabolic pathways, circulating citrate levels can also be altered, potentially serving as noninvasive biomarkers. In those relying on an oxidative metabolism, fatty acid β-oxidation sustains a high production of citrate, which is still rapidly converted into acetyl-CoA and oxaloacetate, this latter molecule sustaining nucleotide synthesis and gluconeogenesis. Therefore, citrate levels are rarely high in cancer cells. Citrate is a gauge of nutrients available for biosynthesis and ATP production generated via oxidative phosphorylation (OXPHOS). In addition, citrate is a key regulatory molecule, which targets (directly or indirectly) catabolic and anabolic pathways (fatty acid β-oxidation (FAO) and FAS, glycolysis, and gluconeogenesis) in a manner such that when one pathway is activated, the other is inhibited. For example, citrate directly inhibits the main regulators of glycolysis, phosphofructokinase-1 (PFK1) and phosphofructokinase-2 (PFK2) [2,3], while it enhances gluconeogenesis by promoting fructose-1,6-biphosphatase (FBPase). Hypothesis that a low citrate level promotes the Warburg effect. |
| 1576- | Citrate, | Targeting citrate as a novel therapeutic strategy in cancer treatment |
| - | Review, | Var, | NA |
Query results interpretion may depend on "conditions" listed in the research papers. Such Conditions may include : -low or high Dose -format for product, such as nano of lipid formations -different cell line effects -synergies with other products -if effect was for normal or cancerous cells
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