RAS Interaction with PI3K: More Than Just Another Effector Pathway

An update to experimental and clinical aspects of tumor-associated macrophages in cancer development: hopes and pitfalls

Tumor-associated macrophages (TAMs) represent one of the most abundant tumor-infiltrating stromal cells, and their normal function in tumor microenvironment (TME) is to suppress tumor cells by producing cytokines which trigger both direct cell cytotoxicity and antibody-mediated immune response. However, upon prolonged exposure to TME, the classical function of these so-called M1-type TAMs can be converted to another type, "M2-type," which are recruited by tumor cells so that they promote tumor growth and metastasis. This is the reason why the accumulation of TAMs in TME is correlated with poor prognosis in cancer patients. Both M1- and M2-types have high degree of plasticity, and M2-type cells can be reprogrammed to M1-type for therapeutic purposes. This characteristic introduces TAMs as promising target for developing novel cancer treatments. In addition, inhibition of M2-type cells and blocking their recruitment in TME, as well as their depletion by inducing apoptosis, are other approaches for effective immunotherapy of cancer. In this review, we summarize the potential of TAMs to be targeted for cancer immunotherapy and provide an up-to-date about novel strategies for targeting TAMs.

Combination Therapy Approach to Overcome the Resistance to PI3K Pathway Inhibitors in Gynecological Cancers

The PI3K signaling pathway plays an essential role in cancer cell proliferation and survival. PI3K pathway inhibitors are now FDA-approved as a single agent treatment or in combination for solid tumors such as renal cell carcinoma or breast cancer. However, despite the high prevalence of PI3K pathway alterations in gynecological cancers and promising preclinical activity in endometrial and ovarian cancer models, PI3K pathway inhibitors showed limited clinical activity in gynecological cancers. In this review, we provide an overview on resistance mechanisms against PI3K pathway inhibitors that limit their use in gynecological malignancies, including genetic alterations that reactivate the PI3K pathway such as PIK3CA mutations and PTEN loss, compensatory signaling pathway activation, and feedback loops causing the reactivation of the PI3K signaling pathway. We also discuss the successes and limitations of recent clinical trials aiming to address such resistance mechanisms through combination therapies.

Hyperactivation of MEK1 in cortical glutamatergic neurons results in projection axon deficits and aberrant motor learning

Abnormal extracellular signal-regulated kinase 1/2 (ERK1/2, encoded by Mapk3 and Mapk1, respectively) signaling is linked to multiple neurodevelopmental diseases, especially the RASopathies, which typically exhibit ERK1/2 hyperactivation in neurons and non-neuronal cells. To better understand how excitatory neuron-autonomous ERK1/2 activity regulates forebrain development, we conditionally expressed a hyperactive MEK1 (MAP2K1) mutant, MEK1S217/221E, in cortical excitatory neurons of mice. MEK1S217/221E expression led to persistent hyperactivation of ERK1/2 in cortical axons, but not in soma/nuclei. We noted reduced axonal arborization in multiple target domains in mutant mice and reduced the levels of the activity-dependent protein ARC. These changes did not lead to deficits in voluntary locomotion or accelerating rotarod performance. However, skilled motor learning in a single-pellet retrieval task was significantly diminished in these MEK1S217/221E mutants. Restriction of MEK1S217/221E expression to layer V cortical neurons recapitulated axonal outgrowth deficits but did not affect motor learning. These results suggest that cortical excitatory neuron-autonomous hyperactivation of MEK1 is sufficient to drive deficits in axon outgrowth, which coincide with reduced ARC expression, and deficits in skilled motor learning. Our data indicate that neuron-autonomous decreases in long-range axonal outgrowth may be a key aspect of neuropathogenesis in RASopathies.

Alpelisib decreases nevocytes of congenital melanocytic nevi

BACKGROUND

Multiple, large or giant congenital melanocytic nevi (CMN) are uncommon and affected patients can show progressive growth and thickening, associate neurocutaneous melanocytosis or develop melanoma. Current treatment modalities are mostly complex surgeries that frequently do not solve the disease and its risks completely. Thus, investigation on new treatment options for CMN and its complications must continue. MAPK pathway inhibitors are being investigated, also targeting PI3K-AKT. Omipalisib (PI3K inhibitor, with no indications approved yet) has been studied for CMN in vitro and in mice with promising results. However, alpelisib, a PI3K inhibitor approved with an adequate safety profile for patients with severe manifestations of PROS (PIK3CA-Related Overgrowth Spectrum), had not yet been tested for CMN.

OBJECTIVE

To evaluate the effect of alpelisib in nevocytes of congenital melanocytic nevi.

METHODS

Nevomelanocytic tissue samples of 10 patients were collected prospectively and, following a previously reported preclinical ex vivo model, explants were placed in organotypic culture for 5 days, with or without alpelisib. Consecutively, tissue sections were stained and using scanned images with Qupath and ImageJ softwares, representative regions from the dermis were analysed (using Wilcoxon test and Spearman's correlation).

RESULTS

When comparing alpelisib-treated explants with respect to control explants, we found a decrease in cell density (p = 0.0273), in density of SOX10+-cells (p = 0.0391) and also in the % of S-100+ area (p = 0.0078), in alpelisib samples. The three markers showed a positive correlation (p < 0.05).

CONCLUSIONS

This study provides first-time evidence that alpelisib induces nevocyte reduction in CMN from patient-derived explants, probably inducted by autophagy. Alpelisib is an approved drug with an adequate safety profile used in another mosaicism affecting PI3K (PROS). Further studies are needed to evaluate its efficacy in treating CMN and potentially, their complications, either with local or systemic administration, alone or in combination.

Discovery, optimization and biological activity evaluation of genipin derivatives as potential KRAS G12D inhibitors

A series of genipin derivatives were designed and synthesized as potential inhibitors targeted KRAS G12D mutation. The majority of these compounds demonstrated potential antiproliferative effects against KRAS G12D mutant tumor cells (CT26 and A427). Notably, seven compounds exhibited the anticancer effects with IC50 values ranging from 7.06 to 9.21 µM in CT26 (KRASG12D) and A427 (KRASG12D) cells and effectively suppressed the colony formation of CT26 cells. One representative compound SK12 was selected for further investigation into biological activity and action mechanisms. SK12 markedly induced apoptosis in CT26 cells in a concentration-dependent manner. Moreover, SK12 elevated the levels of reactive oxygen species (ROS) in tumor cells and exhibited a modulatory effect on the KRAS signaling pathway, thereby inhibiting the activation of downstream phosphorylated proteins. The binding affinity of SK12 to KRAS G12D protein was further confirmed by the surface plasmon resonance (SPR) assay with a binding KD of 157 µM. SK12 also exhibited notable anticancer efficacy in a nude mice tumor model. The relative tumor proliferation rate (T/C) of the experimental group (50 mg/kg) was 31.04 % (P < 0.05), while maintaining a commendable safety profile.

Driver Mutations in Pancreatic Cancer and Opportunities for Targeted Therapy

Pancreatic cancer is the sixth leading cause of cancer-related mortality globally. As the most common form of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC) represents up to 95% of all pancreatic cancer cases, accounting for more than 300,000 deaths annually. Due to the lack of early diagnoses and the high refractory response to the currently available treatments, PDAC has a very poor prognosis, with a 5-year overall survival rate of less than 10%. Targeted therapy and immunotherapy are highly effective and have been used for the treatment of many types of cancer; however, they offer limited benefits in pancreatic cancer patients due to tumor-intrinsic and extrinsic factors that culminate in drug resistance. The identification of key factors responsible for PDAC growth and resistance to different treatments is highly valuable in developing new effective therapeutic strategies. In this review, we discuss some molecules which promote PDAC initiation and progression, and their potential as targets for PDAC treatment. We also evaluate the challenges associated with patient outcomes in clinical trials and implications for future research.

Neuroretinal Cell Culture Model as a Tool for the Development of New Therapeutic Approaches for Oxidative Stress-Induced Ocular Diseases, with a Focus on Glaucoma

Glaucoma is a heterogeneous group of optic neuropathies characterized by a progressive degeneration of the retinal ganglion cells (RGCs), leading to irreversible vision loss. Nowadays, the traditional therapeutic approach to glaucoma consists of lowering the intraocular pressure (IOP), which does not address the neurodegenerative features of the disease. Besides animal models of glaucoma, there is a considerable need for in vitro experimental models to propose new therapeutic strategies for this ocular disease. In this study, we elucidated the pathological mechanisms leading to neuroretinal R28 cell death after exposure to glutamate and hydrogen peroxide (H2O2) in order to develop new therapeutic approaches for oxidative stress-induced retinal diseases, including glaucoma. We were able to show that glutamate and H2O2 can induce a decrease in R28 cell viability in a concentration-dependent manner. A cell viability of about 42% was found after exposure to 3 mM of glutamate and about 56% after exposure to 100 µM of H2O2 (n = 4). Label-free quantitative mass spectrometry analysis revealed differential alterations of 193 and 311 proteins in R28 cells exposed to 3 mM of glutamate and 100 µM of H2O2, respectively (FDR < 1%; p < 0.05). Bioinformatics analysis indicated that the protein changes were associated with the dysregulation of signaling pathways, which was similar to those observed in glaucoma. Thus, the proteomic alteration induced by glutamate was associated with the inhibition of the PI3K/AKT signaling pathway. On the other hand, H2O2-induced toxicity in R28 cells was linked to the activation of apoptosis signaling and the inhibition of the mTOR and ERK/MAPK signaling pathways. Furthermore, the data show a similarity in the inhibition of the EIF2 and AMPK signaling pathways and the activation of the sumoylation and WNT/β-catenin signaling pathways in both groups. Our findings suggest that the exposure of R28 cells to glutamate and H2O2 could induce glaucoma-like neurodegenerative features and potentially provide a suitable tool for the development of new therapeutic strategies for retinal diseases.

The Role of Curcumin in Cancer: A Focus on the PI3K/Akt Pathway

Cancer is a life-threatening disease and one of the leading causes of death worldwide. Despite significant advancements in therapeutic options, most available anti-cancer agents have limited efficacy. In this context, natural compounds with diverse chemical structures have been investigated for their multimodal anti-cancer properties. Curcumin is a polyphenol isolated from the rhizomes of Curcuma longa and has been widely studied for its anti-inflammatory, anti-oxidant, and anti-cancer effects. Curcumin acts on the regulation of different aspects of cancer development, including initiation, metastasis, angiogenesis, and progression. The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathway is a key target in cancer therapy, since it is implicated in initiation, proliferation, and cancer cell survival. Curcumin has been found to inhibit the PI3K/Akt pathway in tumor cells, primarily via the regulation of different key mediators, including growth factors, protein kinases, and cytokines. This review presents the therapeutic potential of curcumin in different malignancies, such as glioblastoma, prostate and breast cancer, and head and neck cancers, through the targeting of the PI3K/Akt signaling pathway.

Molecular pathways and therapeutic targets linked to triple-negative breast cancer (TNBC)

Cancer is a group of diseases characterized by uncontrolled cellular growth, abnormal morphology, and altered proliferation. Cancerous cells lose their ability to act as anchors, allowing them to spread throughout the body and infiltrate nearby cells, tissues, and organs. If these cells are not identified and treated promptly, they will likely spread. Around 70% of female breast cancers are caused by a mutation in the BRCA gene, specifically BRCA1. The absence of progesterone, oestrogen and HER2 receptors (human epidermal growth factor) distinguishes the TNBC subtype of breast cancer. There were approximately 6,85,000 deaths worldwide and 2.3 million new breast cancer cases in women in 2020. Breast cancer is the most common cancer globally, affecting 7.8 million people at the end of 2020. Compared to other cancer types, breast cancer causes more women to lose disability-adjusted life years (DALYs). Worldwide, women can develop breast cancer at any age after puberty, but rates increase with age. The maintenance of mammary stem cell stemness is disrupted in TNBC, governed by signalling cascades controlling healthy mammary gland growth and development. Interpreting these essential cascades may facilitate an in-depth understanding of TNBC cancer and the search for an appropriate therapeutic target. Its treatment remains challenging because it lacks specific receptors, which renders hormone therapy and medications ineffective. In addition to radiotherapy, numerous recognized chemotherapeutic medicines are available as inhibitors of signalling pathways, while others are currently undergoing clinical trials. This article summarizes the vital druggable targets, therapeutic approaches, and strategies associated with TNBC.

Discovery of Novel Coumarin-quinolinium Derivatives as Pan-KRAS Translation Inhibitors by Targeting 5'-UTR RNA G-Quadruplexes

Hyperactivated KRAS mutations fuel tumorigenesis and represent attractive targets for cancer treatment. While covalent inhibitors have shown clinical benefits against the KRASG12C mutant, advancements for non-G12C mutants remain limited, highlighting the urgent demand for pan-KRAS inhibitors. RNA G-quadruplexes (rG4s) in the 5'-untranslated region of KRAS mRNA can regulate KRAS translation, making them promising targets for pan-KRAS inhibitor development. Herein, we designed and synthesized 50 novel coumarin-quinolinium derivatives, leveraging our previously developed rG4-specific ligand, QUMA-1. Notably, several compounds exhibited potent antiproliferative activity against cancer cells as pan-KRAS translation inhibitors. Among them, 15a displayed exceptional capability in stabilizing KRAS rG4s, suppressing KRAS translation, and consequently modulating MAPK and PI3K-AKT pathways. 15a induced cell cycle arrest, prompted apoptosis in KRAS-driven cancer cells, and effectively inhibited tumor growth in a KRAS mutant xenograft model. These findings underscore the potential of 15a as a pan-KRAS translation inhibitor, offering a novel and promising approach to target various KRAS-driven cancers.

Advancements in dual-target inhibitors of PI3K for tumor therapy: Clinical progress, development strategies, prospects

Phosphoinositide 3-kinases (PI3Ks) modify lipids by the phosphorylation of inositol phospholipids at the 3'-OH position, thereby participating in signal transduction and exerting effects on various physiological processes such as cell growth, metabolism, and organism development. PI3K activation also drives cancer cell growth, survival, and metabolism, with genetic dysregulation of this pathway observed in diverse human cancers. Therefore, this target is considered a promising potential therapeutic target for various types of cancer. Currently, several selective PI3K inhibitors and one dual-target PI3K inhibitor have been approved and launched on the market. However, the majority of these inhibitors have faced revocation or voluntary withdrawal of indications due to concerns regarding their adverse effects. This article provides a comprehensive review of the structure and biological functions, and clinical status of PI3K inhibitors, with a specific emphasis on the development strategies and structure-activity relationships of dual-target PI3K inhibitors. The findings offer valuable insights and future directions for the development of highly promising dual-target drugs targeting PI3K.

1,8-Dihydroxy-3-methoxy-anthraquinone inhibits tumor angiogenesis through HIF-1α downregulation

Photorhabdus luminescens is a gram-negative bioluminescent bacterium known as an intestinal bacterium that coexists in the digestive tract of insect-pathogenic nematodes. As part of our ongoing exploration to identify bioactive compounds from diverse natural resources, the chemical analysis of the cultures of P. luminescens KACC 12254 via LC/MS and TLC-based analyses enabled the isolation and identification of a major fluorescent compound. Its chemical structure was elucidated as 1,8-dihydroxy-3-methoxyanthraquinone (DMA) using HR-ESI-MS and NMR analysis. In this study, we conducted comprehensive investigations utilizing human colorectal cancer HCT116 cells, human umbilical cord vascular endothelial cells (HUVECs), and zebrafish embryos to assess the potential benefits of DMA in suppressing tumor angiogenesis. Our results convincingly demonstrate that DMA effectively suppresses the stability of hypoxia-inducible factor-1α (HIF-1α) protein and its target genes without inducing any cytotoxic effects. Furthermore, DMA demonstrates the ability to inhibit HIF-1α transcriptional activation and mitigate the production of reactive oxygen species (ROS). In our in vitro experiments, DMA exhibits notable inhibitory effects on VEGF-mediated tube formation, migration, and invasion in HUVECs. Additionally, in vivo investigations using zebrafish embryos confirm the antiangiogenic properties of DMA. Notably, DMA does not exhibit any adverse developmental or cardiotoxic effects in the in vivo setting. Moreover, we observe DMA's capability to restrain tumor growth through the downregulation of PI3K/AKT and c-RAF/ERK pathway. Collectively, these compelling findings underscore DMA's potential as a promising therapeutic candidate for targeted intervention against HIF-1α and angiogenesis in cancer treatment.

Genomic alterations in thyroid cancer: biological and clinical insights

Tumours can arise from thyroid follicular cells if they acquire driver mutations that constitutively activate the MAPK signalling pathway. In addition, a limited set of additional mutations in key genes drive tumour progression towards more aggressive and less differentiated disease. Unprecedented insights into thyroid tumour biology have come from the breadth of thyroid tumour sequencing data from patients and the wide range of mutation-specific mechanisms identified in experimental models, in combination with the genomic simplicity of thyroid cancers. This knowledge is gradually being translated into refined strategies to stratify, manage and treat patients with thyroid cancer. This Review summarizes the biological underpinnings of the genetic alterations involved in thyroid cancer initiation and progression. We also provide a rationale for and discuss specific examples of how to implement genomic information to inform both recommended and investigational approaches to improve thyroid cancer prognosis, redifferentiation strategies and targeted therapies.

Deciphering the role of KRAS gene in oncogenesis: Focus on signaling pathways, genetic alterations in 3'UTR, KRAS specific miRNAs and therapeutic interventions

Cancer is a significant cause of death after cardiovascular disease. The genomic, epigenetic and environmental factors have been found to be the risk factor for the disease. The most important genes that develop cancer are oncogenes and tumor suppressor genes. Among oncogenes, KRAS has emerged as a significant player in the development of many cancers. Dysregulation of the RAS signaling pathway either on account of mutation in significant genes involved in the pathway or aberrant expression of different miRNAs targeting these genes including KRAS. The focus is also on the alterations in 3'UTR of the KRAS gene sequence as well as the changes in the miRNA encoding genes especially the one targeting the KRAS gene. Efforts are also being put in to target the dysregulated KRAS gene as a therapeutic approach to treat different cancers. However, there are some challenges like resistance to KRAS inhibitors that need to be addressed.

K-Ras(V12) differentially affects the three Akt isoforms in lung and pancreatic carcinoma cells and upregulates E-cadherin and NCAM via Akt3

K-Ras is the most frequently mutated Ras variant in pancreatic, colon and non-small cell lung adenocarcinoma. Activating mutations in K-Ras result in increased amounts of active Ras-GTP and subsequently a hyperactivation of effector proteins and downstream signaling pathways. Here, we demonstrate that oncogenic K-Ras(V12) regulates tumor cell migration by activating the phosphatidylinositol 3-kinases (PI3-K)/Akt pathway and induces the expression of E-cadherin and neural cell adhesion molecule (NCAM) by upregulation of Akt3. In vitro interaction and co-precipitation assays identified PI3-Kα as a bona fide effector of active K-Ras4B but not of H-Ras or N-Ras, resulting in enhanced Akt phosphorylation. Moreover, K-Ras(V12)-induced PI3-K/Akt activation enhanced migration in all analyzed cell lines. Interestingly, Western blot analyses with Akt isoform-specific antibodies as well as qPCR studies revealed, that the amount and the activity of Akt3 was markedly increased whereas the amount of Akt1 and Akt2 was downregulated in EGFP-K-Ras(V12)-expressing cell clones. To investigate the functional role of each Akt isoform and a possible crosstalk of the isoforms in more detail, each isoform was stably depleted in PANC-1 pancreatic and H23 lung carcinoma cells. Akt3, the least expressed Akt isoform in most cell lines, is especially upregulated and active in Akt2-depleted cells. Since expression of EGFP-K-Ras(V12) reduced E-cadherin-mediated cell-cell adhesion by induction of polysialylated NCAM, Akt3 was analyzed as regulator of E-cadherin and NCAM. Western blot analyses revealed pronounced reduction of E-cadherin and NCAM in the Akt3-kd cells, whereas Akt1 and Akt2 depletion upregulated E-cadherin, especially in H23 lung carcinoma cells. In summary, we identified oncogenic K-Ras4B as a key regulator of PI3-Kα-Akt signaling and Akt3 as a crucial regulator of K-Ras4B-induced modulation of E-cadherin and NCAM expression and localization.

KRAS Pathways: A Potential Gateway for Cancer Therapeutics and Diagnostics

One of the major disturbing pathways within cancer is "The Kirsten rat sarcoma viral oncogene homolog (KRAS) pathway", and it has recently been demonstrated to be the most crucial in therapies and diagnostics. KRAS pathway includes numerous genes. This multi-component signaling system promotes cell growth, division, survival, and death by transferring signals from outside the cell to its interior. KRAS regulates the activation of a variety of signaling molecules. The KRAS oncogene is a key player in advancing a wide range of malignancies, and the mutation rank of this gene is a key feature of several tumors. For some malignancies, the mutation type of the gene may offer information about prognostic, clinical, and predictive. KRAS belongs to the RAS oncogene family, which consists of a compilation of minor GTP-binding proteins that assimilate environmental inputs and trigger internal signaling pathways that control survival, cell differentiation, and proliferation. This review aims to examine the recent and fascinating breakthroughs in the identification of new therapies that target KRAS, including the ever-expanding experimental approaches for reducing KRAS activity and signaling as well as direct targeting of KRAS. A literature survey was performed. All the relevant articles and patents related to the KRAS pathway, the mutation in the KRAS gene, cancer treatment, and diagnostics were found on PubMed and Google Patents. One of the most prevalent causes of cancer in humans is a mutation in the K-RAS protein. It is extremely difficult to decipher KRAS-mediated signaling. It allows transducing signals to go from the cell's outer surface to its nucleus, having an influence on a variety of crucial cellular functions including cell chemotaxis, division, dissemination, and cell death. Other involved signaling pathways are RAF, and the phosphatidylinositol 3 kinase also known as AKT. The EGFR pathway is incomplete without KRAS. The activation of PI3K significantly contributes to acquiring resistance to a mixture of MEK inhibitors and anti-EGFR in colorectal cancer cell lines which are mutated by KRAS. A series of recent patent studies towards cancer diagnostics and therapeutics reveals the paramount importance of mutated protein KRAS as an extensive driver in human tumors. For the prognosis, diagnosis, and treatment of colorectal cancer, KRAS plays a critical role. This review concludes the latest and vowing developments in the discovery of novel techniques for diagnosis and drugs that target KRAS, the advancements in experimental techniques for signaling and inhibiting KRAS function, and the direct targeting of KRAS for cancer therapeutics.

TEAD Inhibition Overcomes YAP1/TAZ-Driven Primary and Acquired Resistance to KRASG12C Inhibitors

Primary/intrinsic and treatment-induced acquired resistance limit the initial response rate to and long-term efficacy of direct inhibitors of the KRASG12C mutant in cancer. To identify potential mechanisms of resistance, we applied a CRISPR/Cas9 loss-of-function screen and observed loss of multiple components of the Hippo tumor suppressor pathway, which acts to suppress YAP1/TAZ-regulated gene transcription. YAP1/TAZ activation impaired the antiproliferative and proapoptotic effects of KRASG12C inhibitor (G12Ci) treatment in KRASG12C-mutant cancer cell lines. Conversely, genetic suppression of YAP1/WWTR1 (TAZ) enhanced G12Ci sensitivity. YAP1/TAZ activity overcame KRAS dependency through two distinct TEAD transcription factor-dependent mechanisms, which phenocopy KRAS effector signaling. First, TEAD stimulated ERK-independent transcription of genes normally regulated by ERK (BIRC5, CDC20, ECT2, FOSL1, and MYC) to promote progression through the cell cycle. Second, TEAD caused activation of PI3K-AKT-mTOR signaling to overcome apoptosis. G12Ci treatment-induced acquired resistance was also caused by YAP1/TAZ-TEAD activation. Accordingly, concurrent treatment with pharmacologic inhibitors of TEAD synergistically enhanced KRASG12C inhibitor antitumor activity in vitro and prolonged tumor suppression in vivo. In summary, these observations reveal YAP1/TAZ-TEAD signaling as a crucial driver of primary and acquired resistance to KRAS inhibition and support the use of TEAD inhibitors to enhance the antitumor efficacy of KRAS-targeted therapies.

SIGNIFICANCE

YAP1/TAZ-TEAD activation compensates for loss of KRAS effector signaling, establishing a mechanistic basis for concurrent inhibition of TEAD to enhance the efficacy of KRASG12C-selective inhibitor treatment of KRASG12C-mutant cancers. See related commentary by Johnson and Haigis, p. 4005.

Identification of genomic alterations with clinical impact in canine splenic hemangiosarcoma

Canine hemangiosarcoma (HSA) is an aggressive cancer of endothelial cells with short survival times. Understanding the genomic landscape of HSA may aid in developing therapeutic strategies for dogs and may also inform therapies for the rare and aggressive human cancer angiosarcoma. The objectives of this study were to build a framework for leveraging real-world genomic and clinical data that could provide the foundation for precision medicine in veterinary oncology, and to determine the relationships between genomic and clinical features in canine splenic HSA. One hundred and nine dogs with primary splenic HSA treated by splenectomy that had tumour sequencing via the FidoCure® Precision Medicine Platform targeted sequencing panel were enrolled. Patient signalment, weight, metastasis at diagnosis and overall survival time were retrospectively evaluated. The incidence of genomic alterations in individual genes and their relationship to patient variables including outcome were assessed. Somatic mutations in TP53 (n = 44), NRAS (n = 20) and PIK3CA (n = 19) were most common. Survival was associated with presence of metastases at diagnosis and germline variants in SETD2 and NOTCH1. Age at diagnosis was associated with somatic NRAS mutations and breed. TP53 and PIK3CA somatic mutations were found in larger dogs, while germline SETD2 variants were found in smaller dogs. We identified both somatic mutations and germline variants associated with clinical variables including age, breed and overall survival. These genetic changes may be useful prognostic factors and provide insight into the genomic landscape of hemangiosarcoma.

Multiomics Analysis Provides Novel Pathways Related to Progression of Heart Failure

BACKGROUND

Despite major advances in pharmacological treatment for patients with heart failure, residual mortality remains high. This suggests that important pathways are not yet targeted by current heart failure therapies.

OBJECTIVES

We sought integration of genetic, transcriptomic, and proteomic data in a large cohort of patients with heart failure to detect major pathways related to progression of heart failure leading to death.

METHODS

We used machine learning methodology based on stacked generalization framework and gradient boosting algorithms, using 54 clinical phenotypes, 403 circulating plasma proteins, 36,046 transcript expression levels in whole blood, and 6 million genomic markers to model all-cause mortality in 2,516 patients with heart failure from the BIOSTAT-CHF (Systems BIOlogy Study to TAilored Treatment in Chronic Heart Failure) study. Results were validated in an independent cohort of 1,738 patients.

RESULTS

The mean age of the patients was 70 years (Q1-Q3: 61-78 years), 27% were female, median N-terminal pro-B-type natriuretic peptide was 4,275 ng/L (Q1-Q3: 2,360-8,486 ng/L), and 7% had heart failure with preserved ejection fraction. During a median follow-up of 21 months, 657 (26%) of patients died. The 4 major pathways with a significant association to all-cause mortality were: 1) the PI3K/Akt pathway; 2) the MAPK pathway; 3) the Ras signaling pathway; and 4) epidermal growth factor receptor tyrosine kinase inhibitor resistance. Results were validated in an independent cohort of 1,738 patients.

CONCLUSIONS

A systems biology approach integrating genomic, transcriptomic, and proteomic data identified 4 major pathways related to mortality. These pathways are related to decreased activation of the cardioprotective ERBB2 receptor, which can be modified by neuregulin.

Case Report: Progressive disease of BRCA2-mutant colon adenocarcinoma following talazoparib therapy

Colorectal cancer (CRC) is currently one of the most common tumor types diagnosed worldwide. In the early stages, the disease responds well to surgical and chemotherapeutic treatment, but in the later stages when therapeutic options are exhausted, comprehensive genomic profiling can guide further treatment decisions. We present the case of a 46-year-old man of Ashkenazi Jewish ancestry who was diagnosed with KRAS-mutated metastatic colorectal cancer. After surgery and progression on standard FOLFOX/FOLFIRI + bevacizumab therapy, as well as on Trifluridine/Tipiracil, comprehensive genomic profiling was performed with the hope of expanding therapeutic options. Following comprehensive tumor molecular profiling via NGS, a discussion of the case was discussed at the local molecular tumor board in order to determine further treatment strategy. An activating variant of KRAS and PIK3CA, FLT3 and SRC amplification and damaging TP53 and APC variants were discarded by MTB as potential targetable biomarkers. The BRCA2 p.S1415fs*4 founder frameshift variant was of interest and the patient was included in the clinical trial investigating the efficacy of a PARP inhibitor talazoparib. Unfortunately, the disease progression was detected within one month of talazoparib treatment and the patient died during the 8th cycle of FOLFIRI + bevacizumab therapy rechallenge.

New insights into RAS in head and neck cancer

RAS genes are known to be dysregulated in cancer for several decades, and substantial effort has been dedicated to develop agents that reduce RAS expression or block RAS activation. The recent introduction of RAS inhibitors for cancer patients highlights the importance of comprehending RAS alterations in head and neck cancer (HNC). In this regard, we examine the published findings on RAS alterations and pathway activations in HNC, and summarize their role in HNC initiation, progression, and metastasis. Specifically, we focus on the intrinsic role of mutated-RAS on tumor cell signaling and its extrinsic role in determining tumor-microenvironment (TME) heterogeneity, including promoting angiogenesis and enhancing immune escape. Lastly, we summarize the intrinsic and extrinsic role of RAS alterations on therapy resistance to outline the potential of targeting RAS using a single agent or in combination with other therapeutic agents for HNC patients with RAS-activated tumors.

Exploring pathway interactions to detect molecular mechanisms of disease: 22q11.2 deletion syndrome

BACKGROUND

22q11.2 Deletion Syndrome (22q11DS) is a genetic disorder characterized by the deletion of adjacent genes at a location specified as q11.2 of chromosome 22, resulting in an array of clinical phenotypes including autistic spectrum disorder, schizophrenia, congenital heart defects, and immune deficiency. Many characteristics of the disorder are known, such as the phenotypic variability of the disease and the biological processes associated with it; however, the exact and systemic molecular mechanisms between the deleted area and its resulting clinical phenotypic expression, for example that of neuropsychiatric diseases, are not yet fully understood.

RESULTS

Using previously published transcriptomics data (GEO:GSE59216), we constructed two datasets: one set compares 22q11DS patients experiencing neuropsychiatric diseases versus healthy controls, and the other set 22q11DS patients without neuropsychiatric diseases versus healthy controls. We modified and applied the pathway interaction method, originally proposed by Kelder et al. (2011), on a network created using the WikiPathways pathway repository and the STRING protein-protein interaction database. We identified genes and biological processes that were exclusively associated with the development of neuropsychiatric diseases among the 22q11DS patients. Compared with the 22q11DS patients without neuropsychiatric diseases, patients experiencing neuropsychiatric diseases showed significant overrepresentation of regulated genes involving the natural killer cell function and the PI3K/Akt signalling pathway, with affected genes being closely associated with downregulation of CRK like proto-oncogene adaptor protein. Both the pathway interaction and the pathway overrepresentation analysis observed the disruption of the same biological processes, even though the exact lists of genes collected by the two methods were different.

CONCLUSIONS

Using the pathway interaction method, we were able to detect a molecular network that could possibly explain the development of neuropsychiatric diseases among the 22q11DS patients. This way, our method was able to complement the pathway overrepresentation analysis, by filling the knowledge gaps on how the affected pathways are linked to the original deletion on chromosome 22. We expect our pathway interaction method could be used for problems with similar contexts, where complex genetic mechanisms need to be identified to explain the resulting phenotypic plasticity.

Insulin Receptor Isoforms and Insulin Growth Factor-like Receptors: Implications in Cell Signaling, Carcinogenesis, and Chemoresistance

This comprehensive review thoroughly explores the intricate involvement of insulin receptor (IR) isoforms and insulin-like growth factor receptors (IGFRs) in the context of the insulin and insulin-like growth factor (IGF) signaling (IIS) pathway. This elaborate system encompasses ligands, receptors, and binding proteins, giving rise to a wide array of functions, including aspects such as carcinogenesis and chemoresistance. Detailed genetic analysis of IR and IGFR structures highlights their distinct isoforms, which arise from alternative splicing and exhibit diverse affinities for ligands. Notably, the overexpression of the IR-A isoform is linked to cancer stemness, tumor development, and resistance to targeted therapies. Similarly, elevated IGFR expression accelerates tumor progression and fosters chemoresistance. The review underscores the intricate interplay between IRs and IGFRs, contributing to resistance against anti-IGFR drugs. Consequently, the dual targeting of both receptors could present a more effective strategy for surmounting chemoresistance. To conclude, this review brings to light the pivotal roles played by IRs and IGFRs in cellular signaling, carcinogenesis, and therapy resistance. By precisely modulating these receptors and their complex signaling pathways, the potential emerges for developing enhanced anti-cancer interventions, ultimately leading to improved patient outcomes.

The spectrum of MAPK-ERK pathway genomic alterations in gynecologic malignancies: Opportunities for novel therapeutic approaches

OBJECTIVE

To investigate the incidence of MAPK/ERK pathway genomic alterations among patients with gynecologic malignancies.

METHODS

We accessed the American Association of Cancer Research Genomics Evidence of Neoplasia Information Exchange publicly available dataset (v13.0). Patients with malignant tumors of the ovary, uterus, and cervix were identified. Following stratification by tumor site and histology, we examined the prevalence of MAPK/ERK pathway gene alterations (somatic mutation, and/or structural chromosome alterations). We included the following RAS-MAPK pathway genes known to be implicated in the dysregulation of the pathway; KRAS, NRAS, BRAF, HRAS, MAP2K1, RAF1, PTPN11, NF1, and ARAF. Data from the OncoKB database, as provided by cBioPortal, were utilized to determine pathogenic gene alterations.

RESULTS

We identified a total of 10,233 patients with gynecologic malignancies; 48.2% (n = 4937) with ovarian, 45.2% (n = 4621) with uterine and 6.6% (n = 675) with cervical cancer respectively. The overall incidence of MAPK pathway gene alterations was 21%; the most commonly altered gene was KRAS (13%), followed by NF1 (7%), NRAS (1.3%), and BRAF (1.2%). The highest incidence was observed among patients with mucinous ovarian (71%), low-grade serous ovarian (48%), endometrioid ovarian (37%), and endometrioid endometrial carcinoma (34%).

CONCLUSIONS

Approximately 1 in 5 patients with a gynecologic tumor harbor a MAPK/ERK pathway genomic alteration. Novel treatment strategies capitalizing on these alterations are warranted.

Exploring the Molecular Landscape of Myelofibrosis, with a Focus on Ras and Mitogen-Activated Protein (MAP) Kinase Signaling

Myelofibrosis (MF) is a clonal myeloproliferative neoplasm (MPN) characterized clinically by cytopenias, fatigue, and splenomegaly stemming from extramedullary hematopoiesis. MF commonly arises from mutations in JAK2, MPL, and CALR, which manifests as hyperactive Jak/Stat signaling. Triple-negative MF is diagnosed in the absence of JAK2, MPL, and CALR but when clinical, morphologic criteria are met and other mutation(s) is/are present, including ASXL1, EZH2, and SRSF2. While the clinical and classic molecular features of MF are well-established, emerging evidence indicates that additional mutations, specifically within the Ras/MAP Kinase signaling pathway, are present and may play important role in disease pathogenesis and treatment response. KRAS and NRAS mutations alone are reportedly present in up to 15 and 14% of patients with MF (respectively), and other mutations predicted to activate Ras signaling, such as CBL, NF1, BRAF, and PTPN11, collectively exist in as much as 21% of patients. Investigations into the prevalence of RAS and related pathway mutations in MF and the mechanisms by which they contribute to its pathogenesis are critical in better understanding this condition and ultimately in the identification of novel therapeutic targets.

Resistance to KRAS G12C Inhibition in Non-small Cell Lung Cancer

PURPOSE OF REVIEW

Although the recent development of direct KRASG12C inhibitors (G12Ci) has improved outcomes in KRAS mutant cancers, responses occur only in a fraction of patients, and among responders acquired resistance invariably develops over time. Therefore, the characterization of the determinants of acquired resistance is crucial to inform treatment strategies and to identify novel therapeutic vulnerabilities that can be exploited for drug development.

RECENT FINDINGS

Mechanisms of acquired resistance to G12Ci are heterogenous including both on-target and off-target resistance. On-target acquired resistance includes secondary codon 12 KRAS mutations, but also acquired codon 13 and codon 61 alterations, and mutations at drug binding sites. Off-target acquired resistance can derive from activating mutations in KRAS downstream pathway (e.g., MEK1), acquired oncogenic fusions (EML4-ALK, CCDC176-RET), gene level copy gain (e.g., MET amplification), or oncogenic alterations in other pro-proliferative and antiapoptotic pathways (e.g., FGFR3, PTEN, NRAS). In a fraction of patients, histologic transformation can also contribute to the development of acquire resistance. We provided a comprehensive overview of the mechanisms that limit the efficacy of this G12i and reviewed potential strategies to overcome and possibly delay the development of resistance in patients receiving KRAS directed targeted therapies.

Mutant HRas Signaling and Rationale for Use of Farnesyltransferase Inhibitors in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are often associated with poor outcomes, due at least in part to the limited number of treatment options available for those patients who develop recurrent and/or metastatic disease (R/M HNSCC). Even with the recent validation and approval of immunotherapies in the first-line setting for these patients, the need for the development of new and alternative precision medicine strategies with survival benefit is clear. Oncogenic alterations in the HRAS (Harvey rat sarcoma virus) proto-oncogene are seen in approximately 4-8% of R/M HNSCC tumors. Recently, several preclinical and clinical advancements have been made in the implementation of small-molecule inhibitors that block post-translational farnesylation of HRas, thereby abrogating its downstream oncogenic activity. In this review, we focus on the biology of wild-type and mutant HRas signaling in HNSCC, and rationale for use and outcomes of farnesyltransferase inhibitors in patients with HRAS-mutant tumors.

Baseline tumor gene expression signatures correlate with chemoimmunotherapy treatment responsiveness in canine B cell lymphoma

Pet dogs develop spontaneous diffuse large B cell lymphoma (DLBCL), and veterinary clinical trials have been employed to treat canine DLBCL and to inform clinical trials for their human companions. A challenge that remains is selection of treatment to improve outcomes. The dogs in this study were part of a larger clinical trial evaluating the use of combinations of doxorubicin chemotherapy, anti-CD20 monoclonal antibody, and one of three small molecule inhibitors: KPT-9274, TAK-981, or RV1001. We hypothesized that significant differential expression of genes (DEGs) in the tumors at baseline could help predict which dogs would respond better to each treatment based on the molecular pathways targeted by each drug. To this end, we evaluated gene expression in lymph node aspirates from 18 trial dogs using the NanoString nCounter Canine Immuno-oncology (IO) Panel. We defined good responders as those who relapsed after 90 days, and poor responders as those who relapsed prior to 90 days. We analyzed all dogs at baseline and compared poor responders to good responders, and found increased CCND3 correlated with poor prognosis and increased CD36 correlated with good prognosis, as is observed in humans. There was minimal DEG overlap between treatment arms, prompting separate analyses for each treatment cohort. Increased CREBBP and CDKN1A for KPT-9274, increased TLR3 for TAK-981, and increased PI3Kδ, AKT3, and PTEN, and decreased NRAS for RV1001 were associated with better prognoses. Trends for selected candidate biomarker genes were confirmed via qPCR. Our findings emphasize the heterogeneity in DLBCL, similarities and differences between canine and human DLBCL, and ultimately identify biomarkers that may help guide the choice of chemoimmunotherapy treatment in dogs.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Neuroblastoma RAS viral oncogene homolog (N-RAS) deficiency aggravates liver injury and fibrosis

Progressive hepatic damage and fibrosis are major features of chronic liver diseases of different etiology, yet the underlying molecular mechanisms remain to be fully defined. N-RAS, a member of the RAS family of small guanine nucleotide-binding proteins also encompassing the highly homologous H-RAS and K-RAS isoforms, was previously reported to modulate cell death and renal fibrosis; however, its role in liver damage and fibrogenesis remains unknown. Here, we approached this question by using N-RAS deficient (N-RAS-/-) mice and two experimental models of liver injury and fibrosis, namely carbon tetrachloride (CCl4) intoxication and bile duct ligation (BDL). In wild-type (N-RAS+/+) mice both hepatotoxic procedures augmented N-RAS expression in the liver. Compared to N-RAS+/+ counterparts, N-RAS-/- mice subjected to either CCl4 or BDL showed exacerbated liver injury and fibrosis, which was associated with enhanced hepatic stellate cell (HSC) activation and leukocyte infiltration in the damaged liver. At the molecular level, after CCl4 or BDL, N-RAS-/- livers exhibited augmented expression of necroptotic death markers along with JNK1/2 hyperactivation. In line with this, N-RAS ablation in a human hepatocytic cell line resulted in enhanced activation of JNK and necroptosis mediators in response to cell death stimuli. Of note, loss of hepatic N-RAS expression was characteristic of chronic liver disease patients with fibrosis. Collectively, our study unveils a novel role for N-RAS as a negative controller of the progression of liver injury and fibrogenesis, by critically downregulating signaling pathways leading to hepatocyte necroptosis. Furthermore, it suggests that N-RAS may be of potential clinical value as prognostic biomarker of progressive fibrotic liver damage, or as a novel therapeutic target for the treatment of chronic liver disease.

Mechanistic Insights of Thyroid Cancer Progression

Differentiated thyroid cancers (DTCs) are primarily initiated by mutations that activate the MAPK signaling cascade, typically at BRAF or RAS oncoproteins. DTCs can evolve to more aggressive forms, specifically, poorly differentiated (PDTC) and anaplastic thyroid cancers (ATC), by acquiring additional genetic alterations which deregulate key pathways. In this review, we focused on bona fide mutations involved in thyroid cancer progression for which consistent mechanistic data exist. Here we summarized the relevant literature, spanning approximately 2 decades, highlighting genetic alterations that are unquestionably enriched in PDTC/ATC. We describe the relevant functional data obtained in multiple in vitro and in vivo thyroid cancer models employed to study genetic alterations in the following genes and functional groups: TP53, effectors of the PI3K/AKT pathway, TERT promoter, members of the SWI/SNF chromatin remodeling complex, NF2, and EIF1AX. In addition, we briefly discuss other genetic alterations that are selected in aggressive thyroid tumors but for which mechanistic data is still either limited or nonexistent. Overall, we argue for the importance conveyed by preclinical studies for the clinical translation of genomic knowledge of thyroid cancers.

Therapeutic Targeting of Regulated Signaling Pathways of Non-Small Cell Lung Carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common cancer globally. Phytochemicals and small molecule inhibitors significantly prevent varying types of cancers, including NSCLC. These therapeutic molecules serve as important sources for new drugs that interfere with cellular proliferation, apoptosis, metastasis, and angiogenesis by regulating signaling pathways. These molecules affect several cellular signaling cascades, including p53, NF-κB, STAT3, RAS, MAPK/ERK, Wnt, and AKT/PI3K, and are thus implicated in the therapeutic management of cancers. This review aims to describe the bioactive compounds and small-molecule inhibitors, their anticancer action, and targeting cellular signaling cascades in NSCLC. We highlighted the therapeutic potential of Epigallocatechin gallate (EGCG), Perifosine, ABT-737, Thymoquinine, Quercetin, Venetoclax, Gefitinib, and Genistein. These compounds are implicated in the therapeutic management of NSCLC. This review further offers deeper mechanistic insights into different signaling pathways that could be targeted for NSCLC therapy by phytochemicals and small-molecule inhibitors.

Polarization of Cancer-Associated Macrophages Maneuver Neoplastic Attributes of Pancreatic Ductal Adenocarcinoma

Mounting evidence links the phenomenon of enhanced recruitment of tumor-associated macrophages towards cancer bulks to neoplastic growth, invasion, metastasis, immune escape, matrix remodeling, and therapeutic resistance. In the context of cancer progression, naïve macrophages are polarized into M1 or M2 subtypes according to their differentiation status, gene signatures, and functional roles. While the former render proinflammatory and anticancer effects, the latter subpopulation elicits an opposite impact on pancreatic ductal adenocarcinoma. M2 macrophages have gained increasing attention as they are largely responsible for molding an immune-suppressive landscape. Through positive feedback circuits involving a paracrine manner, M2 macrophages can be amplified by and synergized with neighboring neoplastic cells, fibroblasts, endothelial cells, and non-cell autonomous constituents in the microenvironmental niche to promote an advanced disease state. This review delineates the molecular cues expanding M2 populations that subsequently convey notorious clinical outcomes. Future therapeutic regimens shall comprise protocols attempting to abolish environmental niches favoring M2 polarization; weaken cancer growth typically assisted by M2; promote the recruitment of tumoricidal CD8⁺ T lymphocytes and dendritic cells; and boost susceptibility towards gemcitabine as well as other chemotherapeutic agents.

Isoform-specific functions of Ras in T-cell development and differentiation

Ras GTPases, well characterized for their role in oncogenesis, are the cells' molecular switches that signal to maintain immune homeostasis through cellular development, proliferation, differentiation, survival, and apoptosis. In the immune system, T cells are the central players that cause autoimmunity if dysregulated. Antigen-specific T-cell receptor (TCR) stimulation activates Ras-isoforms, which exhibit isoform-specific activator and effector requirements, functional specificities, and a selective role in T-cell development and differentiation. Recent studies show the role of Ras in T-cell-mediated autoimmune diseases; however, there is a scarcity of knowledge about the role of Ras in T-cell development and differentiation. To date, limited studies have demonstrated Ras activation in response to positive and negative selection signals and Ras isoform-specific signaling, including subcellular signaling, in immune cells. The knowledge of isoform-specific functions of Ras in T cells is essential, but still inadequate to develop the T-cell-targeted Ras isoform-specific treatment strategies for the diseases caused by altered Ras-isoform expression and activation in T cells. In this review, we discuss the role of Ras in T-cell development and differentiation, critically analyzing the isoform-specific functions.

RAS-targeted cancer therapy: Advances in drugging specific mutations

Rat sarcoma (RAS), as a frequently mutated oncogene, has been studied as an attractive target for treating RAS-driven cancers for over four decades. However, it is until the recent success of kirsten-RAS (KRAS)^G12C inhibitor that RAS gets rid of the title "undruggable". It is worth noting that the therapeutic effect of KRAS^G12C inhibitors on different RAS allelic mutations or even different cancers with KRAS^G12C varies significantly. Thus, deep understanding of the characteristics of each allelic RAS mutation will be a prerequisite for developing new RAS inhibitors. In this review, the structural and biochemical features of different RAS mutations are summarized and compared. Besides, the pathological characteristics and treatment responses of different cancers carrying RAS mutations are listed based on clinical reports. In addition, the development of RAS inhibitors, either direct or indirect, that target the downstream components in RAS pathway is summarized as well. Hopefully, this review will broaden our knowledge on RAS-targeting strategies and trigger more intensive studies on exploiting new RAS allele-specific inhibitors.

Analysis of context-specific KRAS-effector (sub)complexes in Caco-2 cells

Ras is a key switch controlling cell behavior. In the GTP-bound form, Ras interacts with numerous effectors in a mutually exclusive manner, where individual Ras-effectors are likely part of larger cellular (sub)complexes. The molecular details of these (sub)complexes and their alteration in specific contexts are not understood. Focusing on KRAS, we performed affinity purification (AP)-mass spectrometry (MS) experiments of exogenously expressed FLAG-KRAS WT and three oncogenic mutants ("genetic contexts") in the human Caco-2 cell line, each exposed to 11 different culture media ("culture contexts") that mimic conditions relevant in the colon and colorectal cancer. We identified four effectors present in complex with KRAS in all genetic and growth contexts ("context-general effectors"). Seven effectors are found in KRAS complexes in only some contexts ("context-specific effectors"). Analyzing all interactors in complex with KRAS per condition, we find that the culture contexts had a larger impact on interaction rewiring than genetic contexts. We investigated how changes in the interactome impact functional outcomes and created a Shiny app for interactive visualization. We validated some of the functional differences in metabolism and proliferation. Finally, we used networks to evaluate how KRAS-effectors are involved in the modulation of functions by random walk analyses of effector-mediated (sub)complexes. Altogether, our work shows the impact of environmental contexts on network rewiring, which provides insights into tissue-specific signaling mechanisms. This may also explain why KRAS oncogenic mutants may be causing cancer only in specific tissues despite KRAS being expressed in most cells and tissues.

RAS pathway: The new frontier of brain mosaicism in epilepsy

As cells divide during development, errors in DNA replication and repair lead to somatic mosaicism - a phenomenon in which different cell lineages harbor unique constellations of genetic variants. Over the past decade, somatic variants that disrupt mTOR signaling, protein glycosylation, and other functions during brain development have been linked to cortical malformations and focal epilepsy. More recently, emerging evidence points to a role for Ras pathway mosaicism in epilepsy. The Ras family of proteins is a critical driver of MAPK signaling. Disruption of the Ras pathway is most known for its association with tumorigenesis; however, developmental disorders known as RASopathies commonly have a neurological component that sometimes includes epilepsy, offering evidence for Ras involvement in brain development and epileptogenesis. Brain somatic variants affecting the Ras pathway (e.g., KRAS, PTPN11, BRAF) are now strongly associated with focal epilepsy through genotype-phenotype association studies as well as mechanistic evidence. This review summarizes the Ras pathway and its involvement in epilepsy and neurodevelopmental disorders, focusing on new evidence regarding Ras pathway mosaicism and the potential future clinical implications.

Kaposiform lymphangiomatosis: Diagnosis, pathogenesis, and treatment

Kaposiform lymphangiomatosis (KLA) is a life-threatening rare disease that can cause substantial morbidity, mortality, and social burdens for patients and their families. Diagnosis often occurs long after initial symptoms, and there are few centers in the world with the expertise to diagnose and care for patients with the disease. KLA is a lymphatic anomaly and significant advancements have been made in understanding its pathogenesis and etiology since its first description in 2014. This review provides multidisciplinary, comprehensive, and state-of-the-art information on KLA patient presentation, diagnostic imaging, pathology, organ involvement, genetics, and pathogenesis. Finally, we describe current therapeutic approaches, important areas for research, and challenges faced by patients and their families. Further insights into the pathogenesis of KLA may advance our understanding of other vascular anomalies given that similar signaling pathways may be involved.

ABL1 kinase as a tumor suppressor in AML1-ETO and NUP98-PMX1 leukemias

Deletion of ABL1 was detected in a cohort of hematologic malignancies carrying AML1-ETO and NUP98 fusion proteins. Abl1-/- murine hematopoietic cells transduced with AML1-ETO and NUP98-PMX1 gained proliferation advantage when compared to Abl1 + /+ counterparts. Conversely, overexpression and pharmacological stimulation of ABL1 kinase resulted in reduced proliferation. To pinpoint mechanisms facilitating the transformation of ABL1-deficient cells, Abl1 was knocked down in 32Dcl3-Abl1ko cells by CRISPR/Cas9 followed by the challenge of growth factor withdrawal. 32Dcl3-Abl1ko cells but not 32Dcl3-Abl1wt cells generated growth factor-independent clones. RNA-seq implicated PI3K signaling as one of the dominant mechanisms contributing to growth factor independence in 32Dcl3-Abl1ko cells. PI3K inhibitor buparlisib exerted selective activity against Lin-cKit+ NUP98-PMX1;Abl1-/- cells when compared to the Abl1 + /+ counterparts. Since the role of ABL1 in DNA damage response (DDR) is well established, we also tested the inhibitors of ATM (ATMi), ATR (ATRi) and DNA-PKcs (DNA-PKi). AML1-ETO;Abl1-/- and NUP98-PMX1;Abl1-/- cells were hypersensitive to DNA-PKi and ATRi, respectively, when compared to Abl1 + /+ counterparts. Moreover, ABL1 kinase inhibitor enhanced the sensitivity to PI3K, DNA-PKcs and ATR inhibitors. In conclusion, we showed that ABL1 kinase plays a tumor suppressor role in hematological malignancies induced by AML1-ETO and NUP98-PMX1 and modulates the response to PI3K and/or DDR inhibitors.

Effects of constitutively active K-Ras on axon regeneration after optic nerve injury

Visual disturbance after optic nerve injury is a serious problem. Attempts have been made to enhance the intrinsic ability of retinal ganglion cells (RGCs) to regenerate their axons, and the importance of PI3K/Akt and RAF/MEK/ERK signal activation has been suggested. Since these signals are shared with oncogenic signaling cascades, in this study, we focused on a constitutively active form of K-Ras, K-Ras^V12, to determine if overexpression of this molecule could stimulate axon regeneration. We confirmed that K-Ras^V12 phosphorylated Akt and ERK in vitro. Intravitreal delivery of AAV2-K-Ras^V12 increased the number of surviving RGCs and promoted 1.0 mm of axon regeneration one week after optic nerve injury without inducing abnormal proliferative effects in the RGCs. In addition, AAV2-K-Ras^V12 induced robust RGC axon regeneration, reaching as far as approximately 2.5 mm from the injury site, in eight weeks. Our findings suggest that AAV2-K-Ras^V12 could provide a good model for speedy and efficient analysis of the mechanism underlying axon regeneration in vivo.

An integrated genetic analysis of epileptogenic brain malformed lesions

Focal cortical dysplasia is the most common malformation during cortical development, sometimes excised by epilepsy surgery and often caused by somatic variants of the mTOR pathway genes. In this study, we performed a genetic analysis of epileptogenic brain malformed lesions from 64 patients with focal cortical dysplasia, hemimegalencephy, brain tumors, or hippocampal sclerosis. Targeted sequencing, whole-exome sequencing, and single nucleotide polymorphism microarray detected four germline and 35 somatic variants, comprising three copy number variants and 36 single nucleotide variants and indels in 37 patients. One of the somatic variants in focal cortical dysplasia type IIB was an in-frame deletion in MTOR, in which only gain-of-function missense variants have been reported. In focal cortical dysplasia type I, somatic variants of MAP2K1 and PTPN11 involved in the RAS/MAPK pathway were detected. The in-frame deletions of MTOR and MAP2K1 in this study resulted in the activation of the mTOR pathway in transiently transfected cells. In addition, the PTPN11 missense variant tended to elongate activation of the mTOR or RAS/MAPK pathway, depending on culture conditions. We demonstrate that epileptogenic brain malformed lesions except for focal cortical dysplasia type II arose from somatic variants of diverse genes but were eventually linked to the mTOR pathway.

Exploiting the intrinsic misfolding propensity of the KRAS oncoprotein

Mutant KRAS is a major driver of oncogenesis in a multitude of cancers but remains a challenging target for classical small molecule drugs, motivating the exploration of alternative approaches. Here, we show that aggregation-prone regions (APRs) in the primary sequence of the oncoprotein constitute intrinsic vulnerabilities that can be exploited to misfold KRAS into protein aggregates. Conveniently, this propensity that is present in wild-type KRAS is increased in the common oncogenic mutations at positions 12 and 13. We show that synthetic peptides (Pept-ins™) derived from two distinct KRAS APRs could induce the misfolding and subsequent loss of function of oncogenic KRAS, both of recombinantly produced protein in solution, during cell-free translation and in cancer cells. The Pept-ins exerted antiproliferative activity against a range of mutant KRAS cell lines and abrogated tumor growth in a syngeneic lung adenocarcinoma mouse model driven by mutant KRAS G12V. These findings provide proof-of-concept that the intrinsic misfolding propensity of the KRAS oncoprotein can be exploited to cause its functional inactivation.

Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario

Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.

Binding of active Ras and its mutants to the Ras binding domain of PI-3-kinase: A quantitative approach to KD measurements

Ras family GTPases (H/K/N-Ras) modulate numerous effectors, including the lipid kinase PI3K (phosphatidylinositol-3-kinase) that generates growth signal lipid PIP3 (phosphatidylinositol-3,4,5-triphosphate). Active GTP-Ras binds PI3K with high affinity, thereby stimulating PIP3 production. We hypothesize the affinity of this binding interaction could be significantly increased or decreased by Ras mutations at PI3K contact positions, with clinical implications since some Ras mutations at PI3K contact positions are disease-linked. To enable tests of this hypothesis, we have developed an approach combining UV spectral deconvolution, HPLC, and microscale thermophoresis to quantify the KD for binding. The approach measures the total Ras concentration, the fraction of Ras in the active state, and the affinity of active Ras binding to its docking site on PI3K Ras binding domain (RBD) in solution. The approach is illustrated by KD measurements for the binding of active H-Ras and representative mutants, each loaded with GTP or GMPPNP, to PI3Kγ RBD. The findings demonstrate that quantitation of the Ras activation state increases the precision of KD measurements, while also revealing that Ras mutations can increase (Q25L), decrease (D38E, Y40C), or have no effect (G13R) on PI3K binding affinity. Significant Ras affinity changes are predicted to alter PI3K regulation and PIP3 growth signals.

Therapeutic targeting of hepatocellular carcinoma cells with antrocinol, a novel, dual-specificity, small-molecule inhibitor of the KRAS and ERK oncogenic signaling pathways

Until recently, sorafenib has been the only treatment approved by the U.S. Food and Drug Administration for patients with advanced hepatocellular carcinoma (HCC). Some patients, however, exhibit resistance to this treatment and subsequently experience cancer progression, recurrence, or death. Therefore, identifying a new alternative treatment for patients with little or no response to sorafenib treatment is vital. In this study, we explored the therapeutic potential and underlying molecular mechanism of antrocinol ((3aS,4R,6aS,10aR)-4-(hydroxymethyl)-7,7-dimethyldecahydro-1H-naphtho[1,8a-c]furan-1-one) in patients with HCC. The results indicated that antrocinol was more therapeutically effective than antrocin, Stivarga, and sorafenib against HCC cell lines. Antrocinol also substantially suppressed the expression of KRAS-GTP, p-MEK1/2, p-ERK1/2, and p-AKT in the Huh7 cell line. Additionally, antrocinol-induced apoptosis in the Huh7 cell line, inhibited the formation of tumorspheres, and suppressed the expression of cancer stem cell markers CD133, KLF4, CD44, OCT4, SOX2, and c-Myc. Animal studies revealed that antrocinol alone considerably suppressed tumor growth in nonobese diabetic/severe combined immunodeficient mice inoculated with Huh7 tumorspheres. It also synergistically enhanced the anticancer effect of sorafenib, resulting in enhanced suppression of tumor growth (p < 0.001) and tumorsphere formation (p < 0.001). In tumor samples resected from mice treated with antrocinol alone or in combination with sorafenib, immunohistochemical analysis revealed an increase in BAX expression and a decrease in ERK and AKT protein expression. To the best of our knowledge, this is the first report of the anti-HCC activity of antrocinol. With its higher therapeutic efficacy than that of sorafenib, antrocinol is a candidate drug for patients with HCC who demonstrate little or no response to sorafenib treatment.

Novel Insights into the Role of Kras in Myeloid Differentiation: Engaging with Wnt/β-Catenin Signaling

Cells of the HL-60 myeloid leukemia cell line can be differentiated into neutrophil-like cells by treatment with dimethyl sulfoxide (DMSO). The molecular mechanisms involved in this differentiation process, however, remain unclear. This review focuses on the differentiation of HL-60 cells. Although the Ras proteins, a group of small GTP-binding proteins, are ubiquitously expressed and highly homologous, each has specific molecular functions. Kras was shown to be essential for normal mouse development, whereas Hras and Nras are not. Kras knockout mice develop profound hematopoietic defects, indicating that Kras is required for hematopoiesis in adults. The Wnt/β-catenin signaling pathway plays a crucial role in regulating the homeostasis of hematopoietic cells. The protein β-catenin is a key player in the Wnt/β-catenin signaling pathway. A great deal of evidence shows that the Wnt/β-catenin signaling pathway is deregulated in malignant tumors, including hematological malignancies. Wild-type Kras acts as a tumor suppressor during DMSO-induced differentiation of HL-60 cells. Upon DMSO treatment, Kras translocates to the plasma membrane, and its activity is enhanced. Inhibition of Kras attenuates CD11b expression. DMSO also elevates levels of GSK3β phosphorylation, resulting in the release of unphosphorylated β-catenin from the β-catenin destruction complex and its accumulation in the cytoplasm. The accumulated β-catenin subsequently translocates into the nucleus. Inhibition of Kras attenuates Lef/Tcf-sensitive transcription activity. Thus, upon treatment of HL-60 cells with DMSO, wild-type Kras reacts with the Wnt/β-catenin pathway, thereby regulating the granulocytic differentiation of HL-60 cells. Wild-type Kras and the Wnt/β-catenin signaling pathway are activated sequentially, increasing the levels of expression of C/EBPα, C/EBPε, and granulocyte colony-stimulating factor (G-CSF) receptor.

Cellular signals integrate cell cycle and metabolic control in cancer

Growth factors are the small peptides that can promote growth, differentiation, and survival of most living cells. However, aberrant activation of receptor tyrosine kinases by GFs can generate oncogenic signals, resulting in oncogenic transformation. Accumulating evidence support a link between GF/RTK signaling through the major signaling pathways, Ras/Erk and PI3K/Akt, and cell cycle progression. In response to GF signaling, the quiescent cells in the G₀ stage can re-enter the cell cycle and become the proliferative stage. While in the proliferative stage, tumor cells undergo profound changes in their metabolism to support biomass production and bioenergetic requirements. Accumulating data show that the cell cycle regulators, specifically cyclin D, cyclin B, Cdk2, Cdk4, and Cdk6, and anaphase-promoting complex/cyclosome (APC/C-Cdh1) play critical roles in modulating various metabolic pathways. These cell cycle regulators can regulate metabolic enzyme activities through post-translational mechanisms or the transcriptional factors that control the expression of the metabolic genes. This fine-tune control allows only the relevant metabolic pathways to be active in a particular phase of the cell cycle, thereby providing suitable amounts of biosynthetic precursors available during the proliferative stage. The imbalance of metabolites in each cell cycle phase can induce cell cycle arrest followed by p53-induced apoptosis.

Interactions of melatonin with various signaling pathways: implications for cancer therapy

Melatonin is a neuro-hormone with conserved roles in evolution. Initially synthetized as an antioxidant molecule, it has gained prominence as a key molecule in the regulation of the circadian rhythm. Melatonin exerts its effect by binding to cytoplasmic and intra-nuclear receptors, and is able to regulate the expression of key mediators of different signaling pathways. This ability has led scholars to investigate the role of melatonin in reversing the process of carcinogenesis, a process in which many signaling pathways are involved, and regulating these pathways may be of clinical significance. In this review, the role of melatonin in regulating multiple signaling pathways with important roles in cancer progression is discussed, and evidence regarding the beneficence of targeting malignancies with this approach is presented.

Sushi domain-containing protein 4 binds to epithelial growth factor receptor and initiates autophagy in an EGFR phosphorylation independent manner

BACKGROUND

Sushi domain-containing protein 4 (SUSD4) is a recently discovered protein with unknown cellular functions. We previously revealed that SUSD4 can act as complement inhibitor and as a potential tumor suppressor.

METHODS

In a syngeneic mouse model of breast cancer, tumors expressing SUSD4 had a smaller volume compared with the corresponding mock control tumors. Additionally, data from three different expression databases and online analysis tools confirm that for breast cancer patients, high mRNA expression of SUSD4 in the tumor tissue correlates with a better prognosis. In vitro experiments utilized triple-negative breast cancer cell lines (BT-20 and MDA-MB-468) stably expressing SUSD4. Moreover, we established a cell line based on BT-20 in which the gene for EGFR was knocked out with the CRISPR-Cas9 method.

RESULTS

We discovered that the Epithelial Growth Factor Receptor (EGFR) interacts with SUSD4. Furthermore, triple-negative breast cancer cell lines stably expressing SUSD4 had higher autophagic flux. The initiation of autophagy required the expression of EGFR but not phosphorylation of the receptor. Expression of SUSD4 in the breast cancer cells led to activation of the tumor suppressor LKB1 and consequently to the activation of AMPKα1. Finally, autophagy was initiated after stimulation of the ULK1, Atg14 and Beclin-1 axis in SUSD4 expressing cells.

CONCLUSIONS

In this study we provide novel insight into the molecular mechanism of action whereby SUSD4 acts as an EGFR inhibitor without affecting the phosphorylation of the receptor and may potentially influence the recycling of EGFR to the plasma membrane.