Arjun Awasthi, PhD, Chief Operating Officer, Avesta Bio, Houston, TX, USA. September 24, 2024
Executive Summary
The deleterious effects of aging are a critical issue. Humans today live longer, but their quality of life is negatively affected by chronic diseases such as diabetes, cancer, and metabolic syndrome. These challenges have become a major focus for many companies researching longevity. Avesta Bio has conducted critical research revealing that the key to longevity may lie in RLIP76.
RLIP76 is a crucial protein involved in protecting cells from oxidative stress, is a critical component of clathrin-dependent endocytosis (CDE), and in controlling key signaling pathways. Inhibition of RLIP76 has demonstrated the complete regression of multiple tumor types, and the absence of RLIP76 prevents the formation and growth of neoplasms [1,2,3]. Additionally, RLIP inhibition has been shown to reduce blood glucose, cholesterol, and triglycerides by approximately 30% in preclinical models, without observed adverse effects [2,4].
Longevity Background
The primary goal of longevity is to improve and potentially extend life by reducing the negative effects of aging. This goal has drawn substantial attention, with the anti-aging drugs market valued at approximately $65.5 billion in 2026 and forecast to reach $91.2 billion by 2030, a compound annual growth rate (CAGR) of 8.6% [5].
Some of the key targets of longevity companies include diabetes, obesity, metabolic syndrome, nonalcoholic steatohepatitis, (NASH or fatty liver disease) and cancer. Avesta Bio has demonstrated that RLIP76 is key to each of these diseases, and that depleting or inhibiting RLIP76 by 50% has a profoundly positive impact on overall health [1].
RLIP76 and Chronic Disease
Oxidative stress is a major factor in many chronic diseases. Oxidative stress results from an imbalance between production and accumulation of reactive oxygen species (ROS) and the ability for the body to detoxify those ROSs [6]. One byproduct of oxidative stress is 4-Hydroxynonenol (4HNE). 4HNE activates stress-activated protein kinases (MAPKs, SAPKs), such as Jun-kinase, to trigger oxidative stress defenses through AP2, NRF2, NFkB, and p53. It also can bind to DNA to directly regulate the transcription of stress, inflammation, and immune-responsive genes [7]. Together, these can have a very negative effect on an organism. High concentrations of 4HNE can cause cancer, obesity, metabolic syndrome, diabetes, and NASH.
RLIP76 is the key to regulating levels of 4HNE, maintaining CDE, and fighting oxidative stress. This was very clearly demonstrated in studies with mice missing RLIP76 (RLIP76-/-). In these studies, the RLIP76-/- mice were under high levels of oxidative stress, but surprisingly, they were sensitive to insulin, they had low blood glucose levels, low cholesterol, low triglycerides, and were nearly completely resistant to obesity [7,8,9]. They were also smaller and had less fat than mice with a full complement of RLIP76 (RLIP76+/+) [4]. Avesta Bio has most frequently demonstrated the effects of RLIP76 depletion in cancer, but these promising results also have a great deal of potential in the treatment of other chronic diseases [1,2,4,9].
Obesity and Metabolic Syndrome
Obesity and metabolic syndrome are two major contributors to chronic diseases. Obesity is defined as having abnormal or excessive fat accumulation, and a BMI over 30. Metabolic syndrome is defined as a collection of conditions-including an increase in visceral fat, high blood pressure, high blood glucose levels, high triglyceride levels, and elevated cholesterol levels [10]. Both metabolic syndrome and obesity increase oxidative stress in the body and contribute to key chronic diseases such as obesity, cancer, and NASH.
Several important studies were conducted to demonstrate that RLIP76 is the key to combating obesity and metabolic syndrome. In one of them, RLIP76-/- mice and RLIP76+/+ mice were both given a high-fat diet (HFD). After 25 weeks, the RLIP76+/+ mice nearly doubled in size, going from an average weight of 27.6 g to 52.1 g. The RLIP76-/- mice, meanwhile, gained only an average of 5 g per mouse [9]. Additionally, this study demonstrated that RLIP76-/- mice were better able to maintain healthier cholesterol, triglyceride, and blood glucose levels even on an HFD [9,11].
Another key study involved giving RLIP76-/- commonly used medications involved in treating metabolic syndrome (Metformin, Lipitor, Gemfibrozil, and Avandia) Each of these medicines are used to control aspects of metabolic syndrome. In RLIP76-/- mice, Metformin and Avandia no longer had any effect on blood glucose levels, Lipitor no longer had any effect on cholesterol, and Gemfibrozil no longer had any effect on triglycerides [12]. Additionally, the RLIP76-/- mice had lower baseline glucose, cholesterol, and triglycerides. This startling result demonstrates RLIP76’s essential role in metabolic regulation. Without RLIP76, the mice start at a better position than RLIP76+/+ mice, and medications used for metabolic syndrome no longer confer their positive benefit [12].
Together, these studies demonstrate that RLIP76 is of central significance in both obesity and metabolic syndrome and by depleting RLIP76, there is the potential to treat obesity and metabolic syndrome.
Diabetes
In diabetes, oxidative stress causes insulin resistance through protein and chemical signaling pathways. Along the protein signaling pathways, oxidative stress exposes pancreatic β-cells to high glucose concentrations. This results in increased intracellular free radical content and inhibited insulin release [4]. Additionally, reactive oxygen species (ROS) generated during oxidative stress activate signaling proteins including stress kinases (e.g., c-Jun NH2-terminal kinase and p38) [4]. These ROSs also activate extracellular receptor kinases that can affect the cellular response to insulin [4].
In parallel to the protein signaling pathway, oxidative stress activates a chemical signaling pathway. This pathway starts with the generation of ROSs and results in the production of 4-Hydroxynonenol (4HNE). 4HNE controls the expression and activity of many signaling proteins involved in insulin resistance and is key in the development of diabetes [4].
Our studies show that RLIP76 is the dominant factor in both the protein and chemical signaling pathways. In mice featuring all of the activated products of the protein signaling pathways (p38, c-Jun NH2, and stress-derived free radicals), RLIP76 still controlled how sensitive the body was to insulin [4]. RLIP76 has also been demonstrated to be the dominant factor in 4HNE levels [13,14].
In studies comparing mice that were RLIP76+/+ with RLIP76−/−, the importance of RLIP76 becomes very clear. RLIP76-/- mice were more sensitive to insulin, had lower blood glucose levels, had better tolerance to glucose, were smaller and had less fat than the RLIP76+/+ mice [4]. Additionally, they retained the protective response of cortisol-induced hyperglycemia, which is critical because it prevents blood sugars from dropping too low [4]. Together these studies demonstrate that inhibition or depletion of RLIP76 could prove to be a crucial treatment for diabetes.
NASH
Non-alcoholic steatohepatitis (NASH) is an advanced form of non-alcoholic fatty liver disease (NAFLD). The buildup of fat causes inflammation and damage, progressing NAFLD to NASH. Left unchecked, NASH can cause scarring of the liver, also known as cirrhosis. It is estimated that over 115 million adults around the world are impacted by NASH [15]. NASH is often closely correlated with obesity and metabolic syndrome, both diseases in which RLIP76 depletion has shown positive results.
A key component in NASH is the activation of AMPK, which leads to over-expression of SREBP-1c, FAS, and ACC1. These are all genes that are over-expressed in obese individuals and have a strong correlation with the development of NAFLD and NASH [16]. Importantly, RLIP76 directly regulates AMPK [17]. By depleting RLIP76, liver damage can be reversed, liver triglycerides can be reduced, and liver enzymes can be normalized [16]. These studies and the underlying relationships between RLIP76, oxidative stress, and weight, indicate that RLIP76 represents a promising target in the treatment of NASH.
Cancer
Among chronic diseases, cancer is among the deadliest. In 2022 alone, more than 9.7 million people died of cancer globally. Nearly all cancers are affected by the tumor suppressor protein p53. Normally, p53 protects cells from tumor formation, growth and spread. P53 is mutated or deleted in 50-60% of all cancers, and the key signaling pathways it regulates are disrupted in the remaining 40-50% of all cancers [18].
Avesta Bio has generated a proprietary dataset that reveals that RLIP76 regulates p53 and its entire signaling network. In mice who are p53-/- and RLIP76+/-, this dataset has very clearly shown that RLIP76 depletion or inhibition reactivates the p53 signaling pathway network and restores the tumor suppressive functions.
As previously mentioned, p53 dysfunction is ubiquitous across human cancers. Its nature as the key tumor suppressor is critical to nearly all types of cancer. RLIP76’s regulation of p53’s signaling pathways presents RLIP76 as essential to cancer formation, growth, and spread. This essential nature has borne out in the in vivo studies in more than a dozen different types of cancer, where depletion or inhibition of RLIP76 has resulted in positive outcomes [1,2,3].
Critically, these results have also come without overt negative toxicities. Systemic RLIP76-depleting treatments did not cause significant organ toxicity, and the animals gained weight normally after treatment, with no adverse effects [19]. Most incredibly, RLIP76 depletion saw p53-/- mice survive a full lifespan of 3 years, an unprecedented result when the median lifespan of a p53-/- mouse is 4½ months [2, 20].
The ramifications of these results are that a treatment focused on RLIP76 has the potential to treat a wide range of cancers, while showing a favorable safety profile in preclinical studies.
References
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