Tagged: Cancer

Trending with Impact: Acute Myeloid Leukemia and Midostaurin Response

April 23, 2021

Researchers examined midostaurin resistance or sensitivity in a cohort of patients with acute myeloid leukemia.

Figure 2: Differential gene expression for midostaurin sensitive vs. resistant samples identifies a unique signature. — **Figure 2:** Differential gene expression for midostaurin sensitive vs. resistant samples identifies a unique signature.

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Acute myeloid leukemia (AML) is a heterogeneous malignancy that most commonly affects older adults, 60 years of age and older. NPM1, DNMT3A, and FLT3 are the most common genomic alterations found within this disease. In about 30% of AML patients, FLT3 is mutated. Midostaurin was the first FDA approved FLT3 inhibitor for AML. While Midostaurin has a successful overall survival benefit, both primary and secondary resistance remains common.

“A subtype of AML, classified by the presence of a FLT3-Internal Tandem Duplication (ITD) mutation, tends to have a worse prognosis with early relapse and death [5].”

Researchers from Oregon Health and Science University and Howard Hughes Medical Institute conducted a study to identify features that may predict response to midostaurin in FLT3 mutant and wild-type samples. They performed an ex vivo drug sensitivity screen on primary and relapsed AML samples, with corresponding targeted sequencing and RNA sequencing. The paper was entitled: “Genomic markers of midostaurin drug sensitivity in FLT3 mutated and FLT3 wild-type acute myeloid leukemia patients.”

The Study

In order to understand the impact that different genomic alterations have on midostaurin response, 214 patients were functionally assessed with midostaurin and their FLT3 status was annotated. Of these patients, the researcher identified 193 primary and 21 relapse AML samples from the Beat AML publicly available dataset. Risk groups within the cohort were as follows: 73 samples were favorable risk, 59 samples were intermediate, and 68 were adverse. The median age of patients in the cohort was 61, with 52% male and 48% female.

“We hypothesized that there are additional genomic alterations and gene expression changes outside of FLT3-ITD mutations that can influence AML sample resistance or sensitivity to midostaurin and aimed to further characterize these factors.”

Drug sensitivity screening, RNA sequencing/expression analysis, custom gene panel (GeneTrails) sequencing and variant detection, exome sequencing and variant detection, internal FLT3-ITD and NPM1 mutation detection, derivation of FLT3-ITD and NPM1 consensus calls, ex vivo functional drug screens, and statistical analysis were the methods used to observe the impact of genomic alterations on midostaurin response.

“Our research explored the multi-targeted nature of midostaurin and suggested a number of molecular mutational patterns that correlated with midostaurin drug sensitivity and resistance in both FLT3-ITD mutated and FLT3-ITD wild-type AML patient samples.”

Results

The researchers observed specific point mutations and gene expression patterns that they believe explain why there is a range of responses to midostaurin treatment. In the FLT3-ITD positive cohort, increased expression of the oncogene RGL4 (and regulator of the Ras-Raf-MEK-ERK cascade) correlated with poorer midostaurin response. In the FLT3-ITD negative cohort, KRAS mutations correlated with a poorer midostaurin response.

“We also observed that 16 / 34 of the most sensitive samples did not harbor a FLT3 mutation and a majority of differentially expressed genes were independent of FLT3 status.”

Conclusion

The authors point out that additional research studies will be needed given that their sample cohort was relatively small. They also note that since there are multiple FLT3 inhibitors available, it is important to understand the sensitivity mechanisms of each intervention in order to better personalize therapy for chemo-refractory or relapsed AML patients.

“Overall, we identify genomic alterations that correlate with midostaurin response independent of FLT3-ITD status, propose that Ras-Raf-MEK-ERK inhibition in combination therapy could limit resistance to midostaurin, and suggest that within the overall AML population there may be therapeutic benefit of midostaurin in patients with certain expression profiles.”

Click here to read the full scientific study, published in Oncotarget.

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Oncotarget

An Overview of Cannabis and Cancer

February 9, 2021

Researchers review different varieties of cannabinoids, the signaling pathways they affect, and their role in different types of cancer.

Close up of female Cannabis flower with a high production of cannabinoid resin

The Top-Performer series highlights research literature published in Oncotarget that has generated a high Altmetric score. Altmetric scores, located at the top-left of trending Oncotarget papers, provide an at-a-glance indication of the volume and type of online attention the research has received. Read Oncotarget’s Top 100 Altmetric papers.

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In a high-rated paper published in 2014 in Oncotarget, researchers from India’s Sanjay Gandhi Post Graduate Institute of Medical Sciences and the United States’ Ohio State University reviewed cannabinoids, their role in different types of cancer, and the signaling pathways they affect. Today, this paper currently presents with an Altmetric Attention score of 200.

“In this review article, we will focus on a broad range of cannabinoids, their receptor dependent and receptor independent functional roles against various cancer types with respect to growth, metastasis, energy metabolism, immune environment, stemness and future perspectives in exploring new possible therapeutic opportunities.”

Cannabinoids and Receptors

“[The] Cannabis sativa plant has been used for several hundreds of years both recreationally and medicinally.”

Researchers trace the earliest archaeological evidence of cannabis medical use back to ancient China, during the Han Dynasty. The use of this plant was recommended for rheumatic pain, constipation, disorders of the female reproductive tract, and malaria, among other conditions. Cannabis sativa contains three major classes of bioactive molecules; flavonoids, terpenoids, and 100+ types of cannabinoids.

Cannabinoids are a family of complex chemicals that activate and bind to two receptors in mammals named central cannabinoid receptor one (CB1) and peripheral cannabinoid receptor two (CB2). These receptors are found abundantly throughout the central nervous system and immune system.

“CB1/2 receptors are also responsible for proliferation, motility, invasion, adhesion and apoptosis of cancer cells both in vitro and in vivo.”

CB1 and CB2 receptors have been used as targets for the treatment of various diseases, including neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and Huntington’s disease, neuropathic and inflammatory pain, glaucoma, multiple sclerosis, cardiovascular disorders, obesity, and more. Today, in addition to inhibiting nausea and emesis, stimulating appetite, improving mood, and relieving pain and insomnia that cancer patients face, cannabinoids used in the targeted killing of tumor cells has been a major discovery in cancer treatment.

“In this review article we focused on the role of cannabinoids in different cancer types and the respective signaling pathways.”

Endocannabinoids

“Endogenous cannabinoids which are produced in our body include lipid molecules containing long-chain polyunsaturated fatty acids, amides, esters and ethers that bind to CB1 or CB2 receptors.”

Endocannabinoids act primarily as neuromodulators, or reverse messengers, which can affect the release of neurotransmitters. They also play important role in regulating inflammation, insulin, and fat and energy metabolism, which affects our mood, appetite, pain sensation, inflammation response, and memory.

Phytocannabinoids

“Phytocannabinoids are only known to occur naturally in significant quantities in the cannabis plant, and are concentrated in a viscous resin that is produced in glandular structures known as trichomes.”

Over 120 phytocannabinoids are capable of interacting within the body’s own biological systems because their structures and behaviors mimic those of endocannabinoids (cannabinoids that are synthesized by our own bodies). The most prevalent natural cannabinoids are delta-9-tetrahydrocannabinol (∆9-THC), cannabidiol (CBD), and cannabinol (CBN).

Synthetic Cannabinoids

“Synthetic cannabinoids are classified on the basis of chemical structure of molecules and they are capable of a more selective activation of cannabinoid receptors [28].”

The researchers explain that synthetic cannabinoids have been used extensively in pharmacology to gain better insight about their action in order to evaluate the potential use of cannabinoids clinically.

Within the synthetic category, classical cannabinoids are compounds isolated from the Cannabis sativa plant or its synthetic analogs. Nonclassical cannabinoids “are a family of AC-bicyclic and ACD-tricyclic cannabinoid analogs.” Aminoalkylindoles are non-cannabinoid molecules given cannabis-mimicking capabilities. Eicosanoids are compounds that can enhance or inhibit physiological and pathophysiological responses. These lipid mediators also have an affinity for CB1 and CB2 receptors.

Cannabinoids in Cancer

Multiple studies have shown that THC, CBD, and synthetic cannabinoids can inhibit breast cancer cell proliferation and drive them toward apoptosis.

“It [breast cancer] is classified into three main subtypes according to their molecular profiles: hormone receptor-positive, HER2-positive (ErbB2-positive, a member of EGFR family) and triple-negative tumors [42-43]. Cannabinoid-based medicines have been useful for the treatment of these three breast cancer subtypes.”

In prostate cancer, CB1 and CB2 expression levels are often higher in prostate cancer tissues and several cell lines compared to normal prostate epithelial cells. Studies have found that cannabinoids have either induced cell death or activated pathways that lead to growth inhibition and increased patient survival.

Preclinical cancer models have shown that cannabinoids can alter gene expression, block enzymes, inhibit signaling pathways, and induce apoptosis in mice with lung cancer. In skin and pancreatic cancers, researchers have found that the activation of CB1/2 receptors induced the apoptotic death of tumorigenic cells, without affecting the normal cells. In bone cancer studies, researchers found that cannabinoids reduced pain and bone loss in mice.

“Cannabinoids could halt tumor development without side effects via specific targeting of CB1/CB2 receptor.”

Cannabinoids have anti-tumorigenic properties in glioma, lymphoma, oral cancers, and thyroid carcinoma. In young people, marijuana smoking has been found to increase the incidence of head and neck cancer, however, cannabinoids have anti-tumor properties.

Conclusion

“Cannabinoids exert a direct anti-proliferative effect on tumors of different origin.”

Given that cannabinoid receptors are often demonstrated to be expressed higher in tumor cells than in normal cells, cannabinoids are more specific to cancer cells than to normal cells. The researchers conclude their review by noting that it is important to identify which cannabinoids are most compatible with an individual cancer or disorder to have the greatest impact on patient outcome.

“It is important to understand which of the cannabinoid receptors are expressed and activated in different tumors as each receptor follows a different signaling mechanism.”

Years after this paper was published, subsequent studies have confirmed and expanded on many ideas mentioned in this review, including the regenerative and pharmacological effects of THC, synthetic cannabis used to treat thrombosis, increased expression of CB2 potentially linked to colon cancer, experiments with cannabis extracts, synergistic combinations of cannabinoids, and much more.

Click here to read the full scientific review, published in Oncotarget.

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Oncotarget

Trending with Impact: Novel MicroRNA Underexpressed in Lung Cancer

February 4, 2021

In search of new ways to target lung cancer cells, researchers in this study demonstrated that miR-708 has anti-tumorigenic properties.

Photomicrograph of fine needle aspiration (FNA) cytology of a pulmonary (lung) nodule showing adenocarcinoma, a type of non small cell carcinoma.

The Trending with Impact series highlights Oncotarget publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news and articles about the latest trending publications here, and at Oncotarget.com.

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Despite the innumerable biomedical advancements made in the detection, classification, and treatment of cancer since the 1971 National Cancer Act, lung cancer survival rates are still staggeringly low. In addition, every year over $12.1 billion is spent on lung cancer care in the United States. Non-small cell lung cancer (NSCLC) contributes to 85% of lung cancers and within this classification there are two main subtypes: adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC).

“Although tumors are differentiated by subtype, LUAD and LUSC are generally treated with the same chemotherapeutics.”

Researchers, from the New Jersey Medical School’s academic health center, Rutgers Biomedical & Health Sciences, say that discovering new biomarkers that can help better distinguish between NSCLC subtypes is necessary to improve patient outcomes. In 2020, they conducted a study of a microRNA that is dysregulated in lung cancer, miR-708, to clarify its tumor suppressive or oncogenic functions within lung cancer cells.

“Lung cancer is a complex collection of deadly diseases that are generally hard to detect and treat. Therefore, it is crucial to develop novel methods to identify, distinguish, and treat lung cancer.”

The Study

The researchers in this study explain that it is crucial to take the entire tumor microenvironment (TME) into consideration when devising treatments for cancerous tumors. Historically, many chemotherapies that have been developed are successful in targeting tumors, but contribute to damaging the surrounding cells and tissues in the TME—contributing to harm and extending recovery time. In newer treatments being developed, researchers have considered the benefits of targeting the pro-tumor effects of particular immune cells and activating the immune system to attack cancer cells.

“miR-708 has previously been described as being both oncogenic and tumor suppressive in lung cancer [63–65]. Therefore, we aimed to clarify the tumor suppressive or oncogenic functions of miR-708 in lung cancer cells.”

This new potential microRNA with potent anti-tumorigenic effects for non-small cell lung cancer (NSCLC) was identified by the researchers. To determine the clinical relevance of miR-708 in lung cancer patients, the researchers analyzed data from The Cancer Genome Atlas (TCGA) using the TCGA-assembler 2 R software package. They used mammalian cell cultures to perform miRNA and 5-Azacytidine treatments, RNA isolation using TRIzol, quantitative real-time RT-PCR, western blot analysis, plasmids, luciferase reporter assays, Enzyme-Linked Immunosorbent Assay (ELISA) analysis, phenotypic assays; Water Soluble Tetrazolium Salts (WST)-1 assay; Ki-67 staining; Annexin V staining; Cell migration assay, and Bioinformatic and statistical analyses.

“We next examined expression of miR-708 in normal and lung cancer cells to determine if our cell lines faithfully replicated clinical data.”

Results

The researchers discovered miR-708 was underexpressed in lung cancer cells compared to normal lung cells. A lower expression of miR-708 correlated with decreased survival in patients with squamous cell carcinoma non-small cell lung cancer. They demonstrated that miR-708 suppressed the production of the pro-tumorigenic hormone called prostaglandin E2 (PGE2) (located in the arachidonic acid (AA) metabolic inflammatory pathway), by directly repressing the expression of COX-2 and mPGES-1 in lung cancer cells.

“We also demonstrated that miR-708 decreases lung cancer cell metabolism (Figure 5), proliferation (Figure 6), survival (Figure 7), and migration (Figure 8).”

Conclusion

The researchers were left with some outstanding questions about miR-708. First, they wondered why miR-708 expression is decreased in lung cancer cells compared to normal cells in the lungs. They suggest the cause may be the hypermethylation of the ODZ4 promoter region in lung cancer cells, a loss of tumor suppressive transcription factors, repressed CHOP activity, or specifically, the glucocorticoid receptor-alpha (GRα) repression of CHOP activity.

“Our work has identified novel tumor suppressive miR-708 functions by suppressing oncogenic PGE2 production through targeting of COX-2 and mPGES-1. These findings could be the foundation for identifying novel miR-708 targets, as well as regulators of miR-708 expression in cancer.”

“Moreover, our study highlights the need to better understand lung cancer biology to improve diagnosis and treatment of lung cancer, ultimately aiming to increase positive patient outcomes.”

Click here to read the full scientific study, published in Oncotarget.

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Mikhail Blagosklonny

Are Anti-aging Drugs the Key to Cancer Prevention?

February 4, 2021

In his recent paper, Dr. Mikhail Blagosklonny explains his perspective on the current landscape of anti-aging drug studies, a key differentiation between healthspan and lifespan variables, and the next steps for human use of anti-aging drugs—beyond clinical trials.

Aging in humans seems as natural as aging in leaves—but is it necessary?

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The process of human aging is a fascinating mystery. Despite all that we do not know, a handful of researchers have dedicated recent decades to the exciting beginnings of solving this biological riddle. One such researcher is Dr. Mikhail Blagosklonny. As a professor of oncology at the Roswell Park Cancer Institute in Buffalo, New York, and Editor-in-Chief at the AgingandOncotarget journals, Dr. Blagosklonny’s mission is to prevent cancer (and other age-related diseases) by inhibiting the aging process—preventing cancer by maintaining youth.

The cover paper chosen for Oncotarget’s Volume 12, Issue #3, is titled, “The goal of geroscience is life extension;” a research perspective written by Dr. Blagosklonny. In this compelling paper, he reflects on the history of anti-aging studies, the differences between drugs that enhance healthspan versus lifespan, and next steps in the human application of anti-aging drugs.

Hyperfunction Theory of Aging

“According to the geroscience hypothesis, aging is a risk factor for diseases [127]. According to hyperfunction theory, in contrast, aging is a sum of all age-related diseases, not their risk factors.”

Dr. Blagosklonny defines aging as a continuation of human development, driven partially by growth-promoting pathways which drive age-related diseases—he has coined this as the hyperfunction theory.

“Hyperfunction (inappropriate activation) of these signaling pathways directly drive all age-related diseases, which are manifestations of aging. We just need clinically available inhibitors (drugs) of these signaling pathways to extend both healthspan and lifespan, by slowing aging.”

Increasing Lifespan via Increasing Healthspan

Before beginning his interpretation of data from previous anti-aging research studies, Dr. Blagosklonny emphasises the importance of correctly measuring healthspan and lifespan. As indicated in his paper title, the goal of geroscience is to extend lifespan by way of extending overall healthspan.

“Healthspan is a period of life without age-related diseases [27]. It is disease-free survival.”

Healthspan can be difficult to measure due to the nature and hidden course of many diseases. If one particular disease is subdued by treatment in a study and healthspan appears to be increased (through one marker of health or another), this does not guarantee that other age-related diseases have been nullified by this treatment. Dr. Blagosklonny explains that accurate measurements of healthspan are important because, based on the hyperfunction theory, aging is the sum of all age-related diseases.

“After all, aging is an exponential increase of death with age and should be measured by deadly diseases.”

Another point he makes is that many anti-aging drug trials have presented results finding increased healthspan in mice without demonstrating an increase in lifespan. Given that increased healthspan should always lead to increased lifespan, it is not sufficient to only measure healthspan without measuring lifespan in animal studies of anti-aging drugs. If lifespan is not increased, the drug does not demonstrate longevity or anti-aging properties.

“So how is it possible that some senolytics, NAD boosters and resveratrol, increase healthspan without lifespan? The simplest explanation is that they do not increase healthspan at all, because such studies use irrelevant or ambiguous markers of health.”

Over the years, numerous initially promising anti-aging drugs have been tested and debunked by researchers. No compound has continued to withstand the many tests, or has delivered consistent results, quite like the unique bacterium, rapamycin.

Anti-aging Properties in Rapamycin

Rapamycin was discovered in 1964 in a test tube sample of dirt taken from Easter Island—a highly remote volcanic island in the Pacific ocean, west of Chile. Initially looking for antibiotics (often uncovered in the dirt) researchers found the rapamycin bacteria unexpectedly. To their surprise, this new bacteria created a defensive chemical with the ability to affect the activity of a protein and homeostatic ATP sensor called the mammalian target of rapamycin, or mTOR. mTOR is now known to function in regulatory pathways that are responsible for governing cell growth.

“It was predicted that rapamycin must extend lifespan before it was shown in any animal [105].”

In 1999, rapamycin was FDA approved to regulate hyperimmunity in transplant patients to help enable their immune system to accept a new organ. Since then, rapamycin’s ability to slow cell growth and proliferation has been widely accepted as an anticancer agent and the focus of anti-aging studies in a number of mouse-modeled trials.

“Since 2009, dozens of studies have shown that rapamycin extends medium and maximum lifespan in both males and females in all strains of normal mice tested, as well as in some cancer-prone and short-lived mice [36, 40–70].

Other Drugs With and Without Anti-aging Potential

In this paper, Dr. Blagosklonny categorizes a list of seemingly debunked anti-aging drugs with little or no results, including antioxidants, resveratrol, curcumin, quercetin (used alone), and spermidine. He explains that some of these drugs may have potential when used in combination with other drugs in future studies.

He acknowledges potential in berberine (one study found promising initial results), fisetin (clinically available and safe for human use), 17-alpha-estradiol (only results in male mice thus far), acarbose (blocks digestion of complex carbs), enalapril (decreases oxidative damage), losartan (angiotensin receptor blocker), quercetin with dasatinib (clinically available and safe for human use), and metformin.

“Some life-extending drugs are already approved for human use: supplements (fisetin, vitamin B3 and its analogs), over-the-counter medicine (aspirin) and prescription drugs (rapamycin, metformin, dasatinib, enilopril).”

Dr. Blagosklonny recalls a famous study of metformin where, at a low doses, it increased lifespan in male mice and, at high doses, it ironically decreased lifespan. Metformin was also tested with rapamycin in this study and demonstrated improved results in extending lifespan.

“Yet, a combination of metformin and rapamycin should be re-tested to include a rapamycin-alone group.”

Conclusion

“I expect that a combination of low doses of pan-mTOR and MEK inhibitors with high doses of rapamycin would extend life further compared with rapamycin alone. That could be the next important advance in the anti-aging field since the discovery of anti-aging properties of rapamycin.”

Dr. Blagosklonny believes that researchers should not wait for the lifespan results of clinical trials in humans to begin widespread application of these drugs, since studies already safely display increased lifespan and longevity in mouse models. He is so convinced by rapamycin that Dr. Blagosklonny is currently taking 10 milligrams of rapamycin per week along with his personalized treatment plan, a ketogenic diet, and exercise to jumpstart the next phase of human anti-aging trials within our lifetime. He notes that medical doctors interested in this topic may email Blagosklonny@rapalogs.com or follow him on Twitter @Blagosklonny.

“This article does not represent medical advice or recommendations to patients. The media should exercise caution and seek expert medical advice for interpretation when referring to this article.”

Click here to read the full research perspective on Oncotarget.com.

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Oncotargetis a unique platform designed to house scientific studies in a journal format that is available for anyone to read—without a paywall making access more difficult. This means information that has the potential to benefit our societies from the inside out can be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.