Deactivation of Glutaminolysis Sensitizes PIK3CA-Mutated Colorectal Cancer Cells to Aspirin-Induced Growth Inhibition

Aspirin reprogrammes colorectal cancer cell metabolism and sensitises to glutaminase inhibition

BACKGROUND

To support proliferation and survival within a challenging microenvironment, cancer cells must reprogramme their metabolism. As such, targeting cancer cell metabolism is a promising therapeutic avenue. However, identifying tractable nodes of metabolic vulnerability in cancer cells is challenging due to their metabolic plasticity. Identification of effective treatment combinations to counter this is an active area of research. Aspirin has a well-established role in cancer prevention, particularly in colorectal cancer (CRC), although the mechanisms are not fully understood.

METHODS

We generated a model to investigate the impact of long-term (52 weeks) aspirin exposure on CRC cells, which has allowed us comprehensively characterise the metabolic impact of long-term aspirin exposure (2-4mM for 52 weeks) using proteomics, Seahorse Extracellular Flux Analysis and Stable Isotope Labelling (SIL). Using this information, we were able to identify nodes of metabolic vulnerability for further targeting, investigating the impact of combining aspirin with metabolic inhibitors in vitro and in vivo.

RESULTS

We show that aspirin regulates several enzymes and transporters of central carbon metabolism and results in a reduction in glutaminolysis and a concomitant increase in glucose metabolism, demonstrating reprogramming of nutrient utilisation. We show that aspirin causes likely compensatory changes that render the cells sensitive to the glutaminase 1 (GLS1) inhibitor-CB-839. Of note given the clinical interest, treatment with CB-839 alone had little effect on CRC cell growth or survival. However, in combination with aspirin, CB-839 inhibited CRC cell proliferation and induced apoptosis in vitro and, importantly, reduced crypt proliferation in Apcfl/fl mice in vivo.

CONCLUSIONS

Together, these results show that aspirin leads to significant metabolic reprogramming in colorectal cancer cells and raises the possibility that aspirin could significantly increase the efficacy of metabolic cancer therapies in CRC.

RDKG-115: Assisting drug repurposing and discovery for rare diseases by trimodal knowledge graph embedding

Rare diseases (RDs) may affect individuals in small numbers, but they have a significant impact on a global scale. Accurate diagnosis of RDs is challenging, and there is a severe lack of drugs available for treatment. Pharmaceutical companies have shown a preference for drug repurposing from existing drugs developed for other diseases due to the high investment, high risk, and long cycle involved in RD drug development. Compared to traditional approaches, knowledge graph embedding (KGE) based methods are more efficient and convenient, as they treat drug repurposing as a link prediction task. KGE models allow for the enrichment of existing knowledge by incorporating multimodal information from various sources. In this study, we constructed RDKG-115, a rare disease knowledge graph involving 115 RDs, composed of 35,643 entities, 25 relations, and 5,539,839 refined triplets, based on 372,384 high-quality literature and 4 biomedical datasets: DRKG, Pathway Commons, PharmKG, and PMapp. Subsequently, we developed a trimodal KGE model containing structure, category, and description embeddings using reverse-hyperplane projection. We utilized this model to infer 4199 reliable new inferred triplets from RDKG-115. Finally, we calculated potential drugs and small molecules for each of the 115 RDs, taking multiple sclerosis as a case study. This study provides a paradigm for large-scale screening of drug repurposing and discovery for RDs, which will speed up the drug development process and ultimately benefit patients with RDs. The source code and data are available at https://github.com/ZhuChaoY/RDKG-115.

Aspirin and the metabolic hallmark of cancer: novel therapeutic opportunities for colorectal cancer

Aspirin is a well-known nonsteroidal anti-inflammatory drug (NSAID) that has a recognized role in cancer prevention as well as evidence to support its use as an adjuvant for cancer treatment. Importantly there has been an increasing number of studies contributing to the mechanistic understanding of aspirins' anti-tumour effects and these studies continue to inform the potential clinical use of aspirin for both the prevention and treatment of cancer. This review focuses on the emerging role of aspirin as a regulator of metabolic reprogramming, an essential "hallmark of cancer" required to support the increased demand for biosynthetic intermediates needed for sustained proliferation. Cancer cells frequently undergo metabolic rewiring driven by oncogenic pathways such as hypoxia-inducible factor (HIF), wingless-related integration site (Wnt), mammalian target of rapamycin (mTOR), and nuclear factor kappa light chain enhancer of activated B cells (NF-κB), which supports the increased proliferative rate as tumours develop and progress. Reviewed here, cellular metabolic reprogramming has been identified as a key mechanism of action of aspirin and include the regulation of key metabolic drivers, the regulation of enzymes involved in glycolysis and glutaminolysis, and altered nutrient utilisation upon aspirin exposure. Importantly, as aspirin treatment exposes metabolic vulnerabilities in tumour cells, there is an opportunity for the use of aspirin in combination with specific metabolic inhibitors in particular, glutaminase (GLS) inhibitors currently in clinical trials such as telaglenastat (CB-839) and IACS-6274 for the treatment of colorectal and potentially other cancers. The increasing evidence that aspirin impacts metabolism in cancer cells suggests that aspirin could provide a simple, relatively safe, and cost-effective way to target this important hallmark of cancer. Excitingly, this review highlights a potential new role for aspirin in improving the efficacy of a new generation of metabolic inhibitors currently undergoing clinical investigation.

Aspirin sensitivity of PIK3CA-mutated Colorectal Cancer: potential mechanisms revisited

PIK3CA mutations are amongst the most prevalent somatic mutations in cancer and are associated with resistance to first-line treatment along with low survival rates in a variety of malignancies. There is evidence that patients carrying PIK3CA mutations may benefit from treatment with acetylsalicylic acid, commonly known as aspirin, particularly in the setting of colorectal cancer. In this regard, it has been clarified that Class IA Phosphatidylinositol 3-kinases (PI3K), whose catalytic subunit p110α is encoded by the PIK3CA gene, are involved in signal transduction that regulates cell cycle, cell growth, and metabolism and, if disturbed, induces carcinogenic effects. Although PI3K is associated with pro-inflammatory cyclooxygenase-2 (COX-2) expression and signaling, and COX-2 is among the best-studied targets of aspirin, the mechanisms behind this clinically relevant phenomenon are still unclear. Indeed, there is further evidence that the protective, anti-carcinogenic effect of aspirin in this setting may be mediated in a COX-independent manner. However, until now the understanding of aspirin's prostaglandin-independent mode of action is poor. This review will provide an overview of the current literature on this topic and aims to analyze possible mechanisms and targets behind the aspirin sensitivity of PIK3CA-mutated cancers.

HepaCAM‑PIK3CA axis regulates the reprogramming of glutamine metabolism to inhibit prostate cancer cell proliferation

Energy metabolism reprogramming is becoming an increasingly important hallmark of cancer. Specifically, cancers tend to undergo metabolic reprogramming to upregulate a cell-dependent glutamine (Gln) metabolism. Notably, hepatocellular cell adhesion molecule (HepaCAM) has been previously reported to serve a key role as a tumour suppressor. However, the possible regulatory role of HepaCAM in Gln metabolism in prostate cancer (PCa) remains poorly understood. In the present study, bioinformatics analysis predicted a significant negative correlation among the expression of HepaCAM, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA), glutaminase (GLS) and solute carrier family 1 member 5 (SLC1A5), components of Gln metabolism, in clinical and genomic datasets. Immunohistochemistry results verified a negative correlation between HepaCAM and PIK3CA expression in PCa tissues. Subsequently, liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) assays were performed, and the results revealed markedly reduced levels of Gln and metabolic flux in the blood samples of patients with PCa and in PCa cells. Mechanistically, overexpression of HepaCAM inhibited Gln metabolism and proliferation by regulating PIK3CA in PCa cells. In addition, Gln metabolism was discovered to be stress-resistant in PCa cells, since the expression levels of GLS and SLC1A5 remained high for a period of time after Gln starvation. However, overexpression of HepaCAM reversed this resistance to some extent. Additionally, alpelisib, a specific inhibitor of PIK3CA, effectively potentiated the inhibitory effects of HepaCAM overexpression on Gln metabolism and cell proliferation through mass spectrometry and CCK-8 experiments. In addition, the inhibitory effect of PIK3CA on the growth of tumor tissue in nude mice was also confirmed by immunohistochemistry in vivo. To conclude, the results from the present study revealed an abnormal Gln metabolic profile in the blood samples of patients with PCa, suggesting that it can be applied as a clinical diagnostic tool for PCa. Additionally, a key role of the HepaCAM/PIK3CA axis in regulating Gln metabolism, cell proliferation and tumour growth was identified. The combination of alpelisib treatment with the upregulation of HepaCAM expression may serve as a novel method for treating patients with PCa.

Glutamine Metabolism Regulators Associated with Cancer Development and the Tumor Microenvironment: A Pan-Cancer Multi-Omics Analysis

Background: In recent years, metabolic reprogramming has been identified as a hallmark of cancer. Accumulating evidence suggests that glutamine metabolism plays a crucial role in oncogenesis and the tumor microenvironment. In this study, we aimed to perform a systematic and comprehensive analysis of six key metabolic node genes involved in the dynamic regulation of glutamine metabolism (referred to as GLNM regulators) across 33 types of cancer. Methods: We analyzed the gene expression, epigenetic regulation, and genomic alterations of six key GLNM regulators, including SLC1A5, SLC7A5, SLC3A2, SLC7A11, GLS, and GLS2, in pan-cancer using several open-source platforms and databases. Additionally, we investigated the impacts of these gene expression changes on clinical outcomes, drug sensitivity, and the tumor microenvironment. We also attempted to investigate the upstream microRNA–mRNA molecular networks and the downstream signaling pathways involved in order to uncover the potential molecular mechanisms behind metabolic reprogramming. Results: We found that the expression levels of GLNM regulators varied across cancer types and were related to several genomic and immunological characteristics. While the immune scores were generally lower in the tumors with higher gene expression, the types of immune cell infiltration showed significantly different correlations among cancer types, dividing them into two clusters. Furthermore, we showed that elevated GLNM regulators expression was associated with poor overall survival in the majority of cancer types. Lastly, the expression of GLNM regulators was significantly associated with PD-L1 expression and drug sensitivity. Conclusions: The elevated expression of GLNM regulators was associated with poorer cancer prognoses and a cold tumor microenvironment, providing novel insights into cancer treatment and possibly offering alternative options for the treatment of clinically refractory cancers.

Does aspirin reduce the incidence, recurrence, and mortality of colorectal cancer? A meta-analysis of randomized clinical trials

BACKGROUND

Colorectal cancer (CRC) is the third most common diagnosed cancer and the third leading cause of all cancer deaths in the USA. Some evidences are shown that aspirin can reduce the morbidity and mortality of different cancers, including CRC. Aspirin has become a new focus of cancer prevention and treatment research so far; clinical studies, however, found conflicting conclusions of its anti-cancer characteristics. This study is to summarize the latest evidence of correlation between aspirin use and CRC and/or colorectal adenomas.

METHODS

Databases were searched to identify randomized controlled trials (RCTs) in the salvage setting. The pooled relative risk (RR) with 95% confidence interval (CI) was used to estimate the effect of aspirin on colorectal cancer and/or colorectal adenomas. Subgroup analysis and sensitivity analysis were also conducted.

RESULTS

The result showed that aspirin use was not associated with incidence of CRC (RR 0.97; 95% CI 0.84-1.12; P = 0.66; I² = 34%), aspirin use was found to be associated with reduced recurrence of colorectal adenomas (RR 0.83; 95% CI 0.72-0.95; P = 0.006; I² = 63%) and reduced mortality of CRC (RR 0.79; 95% CI 0.64-0.97; P = 0.02; I² = 14%). Subgroup analysis found a statistically significant association in low dose with a pooled RR of 0.85 (95% CI 0.74-0.99; P = 0.03; I² = 31%).

CONCLUSIONS

This meta-analysis of randomized controlled trial data indicates that aspirin reduces the overall risk of recurrence and mortality of CRC and/or colorectal adenomas. Incidence of CRC was also reduced with low-dose aspirin. The emerging evidence on aspirin's cancer protection role highlights an exciting time for cancer prevention through low-cost interventions.

TRIAL REGISTRATION

Clinicaltrials.gov no: CRD42020208852; August 18, 2020; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020208852 ).

Rabdosianone I, a Bitter Diterpene from an Oriental Herb, Suppresses Thymidylate Synthase Expression by Directly Binding to ANT2 and PHB2

Simple Summary

In the present study, we found the novel pleiotropic regulation of the oncogene product thymidylate synthase (TS) by a chemical biology approach to identify rabdosianone I-binding proteins. Rabdosianone I, which is extracted from a traditional Asian herb Isodon japonicus Hara for longevity, suppressed TS expression at mRNA and protein levels. We immobilized rabdosianone I onto nano-magnetic beads and identified two mitochondrial proteins, adenine nucleotide translocase 2 (ANT2) and prohibitin 2 (PHB2), as the direct targets of rabdosianone I in cancer cells. Mechanistically, the knockdown of ANT2 or PHB2 promoted proteasomal degradation of the TS protein. In addition, PHB2 reduced TS mRNA levels. Thus, we provide previously unknown mechanisms of TS regulation by ANT2 and PHB2 and propose the possibility of rabdosianone I as a promising lead compound for the discovery of a novel TS suppressor.

Abstract

Natural products have numerous bioactivities and are expected to be a resource for potent drugs. However, their direct targets in cells often remain unclear. We found that rabdosianone I, which is a bitter diterpene from an oriental herb for longevity, Isodon japonicus Hara, markedly inhibited the growth of human colorectal cancer cells by downregulating the expression of thymidylate synthase (TS). Next, using rabdosianone I-immobilized nano-magnetic beads, we identified two mitochondrial inner membrane proteins, adenine nucleotide translocase 2 (ANT2) and prohibitin 2 (PHB2), as direct targets of rabdosianone I. Consistent with the action of rabdosianone I, the depletion of ANT2 or PHB2 reduced TS expression in a different manner. The knockdown of ANT2 or PHB2 promoted proteasomal degradation of TS protein, whereas that of not ANT2 but PHB2 reduced TS mRNA levels. Thus, our study reveals the ANT2- and PHB2-mediated pleiotropic regulation of TS expression and demonstrates the possibility of rabdosianone I as a lead compound of TS suppressor.