Activation Of Signal Transduction Pathways Research Articles

Discovery of N-(2-chloro-5-(3-(pyridin-4-yl)-1H-pyrazolo[3,4-b]pyridin-5-yl)pyridin-3-yl)-4-fluorobenzenesulfonamide (FD274) as a highly potent PI3K/mTOR dual inhibitor for the treatment of acute myeloid leukemia

PI3K-Akt-mTOR pathway is a highly activated signal transduction pathway in human hematological malignancies and has been validated as a promising target for acute myeloid leukemia (AML) therapy. Herein, we designed and synthesized a series of 7-azaindazole derivatives as potent PI3K/mTOR dual inhibitors based on our previously reported FD223. Among them, compound FD274 showed excellent dual PI3K/mTOR inhibitory activity, with IC50 values against PI3Kα/β/γ/δ and mTOR of 0.65 nM, 1.57 nM, 0.65 nM, 0.42 nM, and 2.03 nM, respectively, superior to compound FD223. Compared to the positive drug Dactolisib, FD274 exhibited significant anti-proliferation of AML cell lines (HL-60 and MOLM-16 with IC50 values of 0.092 μM and 0.084 μM, respectively) in vitro. Furthermore, FD274 demonstrated dose-dependent inhibition of tumor growth in the HL-60 xenograft model in vivo, with 91% inhibition of tumor growth at an intraperitoneal injection dose of 10 mg/kg and no observable toxicity. All of these results suggest that FD274 has potential for further development as a promising PI3K/mTOR targeted anti-AML drug candidate.

The loop of phenotype: Dynamic reciprocity links tenocyte morphology to tendon tissue homeostasis.

Cells and their surrounding extracellular matrix (ECM) are engaged in dynamic reciprocity to maintain tissue homeostasis: cells deposit ECM, which in turn presents the signals that define cell identity. This loop of phenotype is obvious for biochemical signals, such as collagens, which are produced by and presented to cells, but the role of biomechanical signals is also increasingly recognised. In addition, cell shape goes hand in hand with cell function and tissue homeostasis. Aberrant cell shape and ECM is seen in pathological conditions, and control of cell shape in micro-fabricated platforms disclose the causal relationship between cell shape and cell function, often mediated by mechanotransduction. In this manuscript, we discuss the loop of phenotype for tendon tissue homeostasis. We describe cell shape and ECM organization in normal and diseased tissue, how ECM composition influences tenocyte shape, and how that leads to the activation of signal transduction pathways and ECM deposition. We further describe the use of technologies to control cell shape to elucidate the link between cell shape and its phenotypical markers and focus on the causal role of cell shape in the loop of phenotype. STATEMENT OF SIGNIFICANCE: The dynamic reciprocity between cells and their surrounding extracellular matrix (ECM) influences biomechanical and biochemical properties of ECM as well as cell function through activation of signal transduction pathways that regulate gene and protein expression. We refer to this reciprocity as Loop of Phenotype and it has been studied and demonstrated extensively by using micro-fabricated platforms to manipulate cell shape and cell fate. In this manuscript, we discuss this concept in tendon tissue homeostasis by giving examples in healthy and pathological tenson tissue. Furthermore, we elaborate this by showing how biomaterials are used to feed this reciprocity to manipulate cell shape and function. Finally, we elucidate the link between cell shape and its phenotypical markers and focus on the activation of signal transduction pathways and ECM deposition.

Role of the phospholipid binding sites, PX of p47phox and PB region of Rac1, in the formation of the phagocyte NADPH oxidase complex NOX2

In phagocytes, superoxide anion (O2−), the precursor of reactive oxygen species, is produced by the NADPH oxidase complex to kill pathogens. Phagocyte NADPH oxidase consists of the transmembrane cytochrome b558 (cyt b558) and four cytosolic components: p40phox, p47phox, p67phox, and Rac1/2. The phagocyte activation by stimuli leads to activation of signal transduction pathways. This is followed by the translocation of cytosolic components to the membrane and their association with cyt b558 to form the active enzyme.To investigate the roles of membrane-interacting domains of the cytosolic proteins in the NADPH oxidase complex assembly and activity, we used giant unilamellar phospholipid vesicles (GUV). We also used the neutrophil-like cell line PLB-985 to investigate these roles under physiological conditions. We confirmed that the isolated proteins must be activated to bind to the membrane. We showed that their membrane binding was strengthened by the presence of the other cytosolic partners, with a key role for p47phox. We also used a fused chimera consisting of p47phox(aa 1–286), p67phox(aa 1–212) and Rac1Q61L, as well as mutated versions in the p47phox PX domain and the Rac polybasic region (PB). We showed that these two domains have a crucial role in the trimera membrane-binding and in the trimera assembly to cyt b558. They also have an impact on O2.- production in vitro and in cellulo: the PX domain strongly binding to GUV made of a mix of polar lipids; and the PB region strongly binding to the plasma membrane of neutrophils and resting PLB-985 cells.

Involvement of CXCL12/CXCR4 axis in colorectal cancer: a mini-review.

Migration of metastatic tumor cells is similar to the traffic of leukocytes and has been reported that can be guided by chemokines and their receptors, through the circulation to distant organs. The chemokine CXCL12 and its receptor CXCR4 play an essential role in hematopoietic stem cell homing and the activation of this axis supports malignant events. Binding of CXCL12 to CXCR4 activates signal transduction pathways, with broad effects on chemotaxis, cell proliferation, migration and gene expression. Thus, this axis serves as a bridge for tumor-stromal cell communication, creating a permissive microenvironment for tumor development, survival, angiogenesis and metastasis. Evidence suggests that this axis may be involved in the colorectal cancer (CRC) carcinogenesis. Therefore, we review emerging data and correlations between CXCL12/CXCR4 axis in CRC, the implications for cancer progression and possible therapeutic strategies that exploit this system.

H2O2 Participates in the Induction and Formation of Potato Tubers by Activating Tuberization-Related Signal Transduction Pathways

Reactive oxygen species (ROS), especially hydrogen peroxide, H2O2, act as signaling molecules to widely mediate growth, development, and stress response of plants. In the present study, internal ROS accumulation, effects of exogenous H2O2 treatment, the expression of the key tuberization-related genes, and the effect of knockout of Solanum tuberosum self-pruning 6A (StSP6A) on H2O2-induced tuber formation were investigated to elucidate whether and how H2O2 is involved in induction and formation of potato tubers using two diploid landraces, Solanum phureja and S. ajanhuiri. The results showed that there was a significant accumulation of ROS (including H2O2, superoxide anion, O2−, and total ROS) during tuber induction and formation in stolons/tubers, especially in the hook-like subapical part of stolons prior to tuberization, as detected by staining observation and quantitative measurement. Furthermore, exogenous H2O2 treatment significantly enhanced percentage of tuber formation. By contrast, addition of either the ROS inhibitor diphenyleneiodonium chloride (DPI) or H2O2 scavenger catalase (CAT) resulted in a decline of tuber formation. In addition, expression analysis of nine key tuberization-related genes demonstrated that the H2O2-induced tuberization could be associated with H2O2-controlled regulation of these tuberization- and signaling-pathway-related genes, especially StSP6A, which was dramatically up-regulated during the early stage of tuber induction and H2O2 treatment. When StSP6A was knocked out by CRISPR-Cas9-mediated genome editing, the tuberization frequency of StSP6A null-mutants became significantly lower at various H2O2 concentration treatments. These findings indicate that H2O2 accumulation in stolons might play an important role by acting as a signaling molecule to initiate tuber induction, H2O2-induced tuber formation is triggered by regulating the tuberization-related gene expression and activating signal transduction pathways, and StSP6A is a pivotal player in H2O2-induced tuber formation in potato.

Deep into the Apoplast: Grapevine and Plasmopara viticola Proteomes Reveal the Secret Beneath Host and Pathogen Communication at 6 h After Contact.

The apoplast is the first hub of plant-pathogen communication where pathogen effectors are recognized by plant defensive proteins and cell receptors, thus activating signal transduction pathways. As a result of this first contact, the host triggers a defense response that involves the modulation of extra- and intracellular proteins. In grapevine-pathogen interactions, little is known about the trafficking between extra- and intracellular spaces. Grapevine is an economically important crop that relies on heavy fungicide use to control several diseases, and a deeper knowledge on the activation of its immune response is crucial to define new control strategies. In this study, we focused on the first 6 h postinoculation with Plasmopara viticola to evaluate grapevine proteome modulation in the apoplast. The in planta P. viticola proteome was also assessed to enable a deeper understanding of plant-pathogen communication. Our results showed that several plant mechanisms are triggered in the tolerant grapevine cultivar Regent after inoculation, such as oomycete recognition, plant cell wall modifications, reactive oxygen species signaling, and secretion of proteins to disrupt oomycete structures. On the other hand, P. viticola proteins related to development and virulence were the most predominant. This pioneer study highlights the early dynamics of cellular communication in grapevine defense that leads to the successful establishment of an incompatible interaction.

The new advance of SALL4 in cancer: Function, regulation, and implication.

SALL4 (split-like protein 4) is a member of the mammalian homologs of the Drosophila homoeotic gene spalt (sal) and acts as a zinc finger transcription factor to govern the self-renewal and pluripotency of embryonic stem cells. SALL4 expression gradually decreases during development and is even absent in most adult tissues. However, increasing evidence suggests that SALL4 expression is restored in human cancers and its aberrant expression is associated with the progression of many hematopoietic malignancies and solid tumors. The potent roles of SALL4 in regulating cancer cell proliferation, apoptosis, metastasis, and drug resistance have been reported. SALL4 plays a dual role in epigenetic modulation by acting as either an activator or a repressor of its target genes. Furthermore, SALL4 interacts with other partners to control the expression of many downstream genes and the activation of various key signaling transduction pathways. SALL4 is considered as a promising diagnostic and prognostic biomarker and therapeutic target for cancer. In this review, we highlighted the major advances in the roles and mechanisms of SALL4 in cancer and the therapeutic strategies for targeting SALL4 to treat cancer.

Advances in molecular evaluation of myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPN) are a group of clonal hematopoietic stem cell disorders with uncontrolled proliferation of one or more hematopoietic cell types, including myeloid, erythroid and megakaryocytic lineages, and minimal defect in maturation. Most MPN are associated with well-defined molecular abnormalities involving genes that encode protein tyrosine kinases that lead to constitutive activation of the downstream signal transduction pathways and confer cells proliferative and survival advantage. Genome-wide sequencing analyses have discovered secondary cooperating mutations that are shared by most of the MPN subtypes as well as other myeloid neoplasms and play a major role in disease progression. Without appropriate management, the natural history of most MPN consists of an initial chronic phase and a terminal blast phase. Molecular aberrations involving protein tyrosine kinases have been used for the diagnosis, classification, detection of minimal/measurable residual disease, and target therapy. We review recent advances in molecular genetic aberrations in MPN with a focus on MPN associated with gene rearrangements or mutations involving tyrosine kinase pathways.

Macrophage metabolic reprogramming and atherosclerotic plaque microenvironment: Fostering each other?

Macrophages are the central immune cells in atherosclerosis (AS) and play a critical role in the initiation, progression and invasion of atherosclerotic plaques. Metabolic reprogramming is a crucial feature that determines macrophage function and is driven by a combination of intrinsic alterations in macrophages and extrinsic factors such as cytokines acting in the plaque microenvironment. Intrinsic macrophage mechanisms activate signal transduction pathways that change metabolic enzyme activity, and the expression of metabolic regulators. Extrinsic signalling mechanisms involve lipids and cytokines in the microenvironment, promoting and amplifying macrophage metabolic reprogramming. This review describes the intrinsic and extrinsic mechanisms driving macrophage metabolic reprogramming in the AS microenvironment and the interplay of these metabolic rewires in the microenvironment. Moreover, we discuss whether targeting these different pathways to treat macrophage microenvironmental changes can alter the fate of the vulnerable plaques.

Interferons and Resistance Mechanisms in Tumors and Pathogen-Driven Diseases-Focus on the Major Histocompatibility Complex (MHC) Antigen Processing Pathway.

Interferons (IFNs), divided into type I, type II, and type III IFNs represent proteins that are secreted from cells in response to various stimuli and provide important information for understanding the evolution, structure, and function of the immune system, as well as the signaling pathways of other cytokines and their receptors. They exert comparable, but also distinct physiologic and pathophysiologic activities accompanied by pleiotropic effects, such as the modulation of host responses against bacterial and viral infections, tumor surveillance, innate and adaptive immune responses. IFNs were the first cytokines used for the treatment of tumor patients including hairy leukemia, renal cell carcinoma, and melanoma. However, tumor cells often develop a transient or permanent resistance to IFNs, which has been linked to the escape of tumor cells and unresponsiveness to immunotherapies. In addition, loss-of-function mutations in IFN signaling components have been associated with susceptibility to infectious diseases, such as COVID-19 and mycobacterial infections. In this review, we summarize general features of the three IFN families and their function, the expression and activity of the different IFN signal transduction pathways, and their role in tumor immune evasion and pathogen clearance, with links to alterations in the major histocompatibility complex (MHC) class I and II antigen processing machinery (APM). In addition, we discuss insights regarding the clinical applications of IFNs alone or in combination with other therapeutic options including immunotherapies as well as strategies reversing the deficient IFN signaling. Therefore, this review provides an overview on the function and clinical relevance of the different IFN family members, with a specific focus on the MHC pathways in cancers and infections and their contribution to immune escape of tumors.

Abstract 6221: Support for targeted therapy selection in triple negative breast cancer patients using aberrant signal transduction pathway activity profiles

Abstract Introduction: Success of therapeutic interventions largely rely on the pathological and biological characteristics of the tumor and varies due to the heterogeneous nature of breast cancers. Triple negative breast cancers (TNBC) stain IHC negative for both hormone receptors (ER, PR) and HER-2. TNBC is usually treated with chemotherapy because of absence of any molecular target. This study is initiated to characterize TNBC based on a new methodology that measures and quantifies signal transduction pathways (STPs) activities to reveal potential tumor-driving STPs in TNBC and create new options for targeted therapy. Method: Using the mRNA-based OncoSIGNal pathway activity profiling PCR test (InnoSIGN) STP activities of 7 pathways (AR, ER, PI3K, MAPK, HH, TGFβ and Notch) in 39 samples from normal breast tissue and 12 TNBC patients were quantified and expressed on a scale from 0-100. Normal healthy breast tissue was obtained from breast reduction surgery and areas where epithelial cells content was at least 50% were annotated and harvested for mRNA isolation and STP analyses. The normal STP activity is representing the normal physiological activity and is used as reference value. Aberrant high pathway activity in a patient tumor sample was concluded when this score was higher than twice the standard deviation above the mean of normal breast tissue STP activity. Results: STP thresholds for interpretation of high aberrant activity were determined from 39 normal breast samples. Using these thresholds, STP activities in 12 TNBC samples were analyzed. In these TNBC samples, MAPK was in 75%, HH in 67%, PI3K in 58%, and AR, Notch and TGFβ were in 17% of the cases above the thresholds. In 50% of the cases a combination of MAPK and HH or a combination of PI3K and HH were found above thresholds. In 42% of the cases MAPK in combination with PI3K were above thresholds. Increased activity of AR was never observed in combination with increased HH activity. Conclusion: By using the OncoSIGNal test high aberrant STP activities could be determined in TNBC patient samples. Results show that different pathways are aberrantly active, depending on the patient sample, which opens the opportunity for personalized targeted treatment of individual TNBC patients. Next steps: The TNBC data set will be extended to further profile the STP activity in relation to different clinical outcomes and to investigate new opportunities for targeted therapies. Citation Format: Diederick M. Keizer, Yvonne J. Wesseling, Dianne A. van Strijp, Saskia M. Vermeer, Eveline C. den Biezen. Support for targeted therapy selection in triple negative breast cancer patients using aberrant signal transduction pathway activity profiles [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6221.

Abstract 958: Signal transduction pathway activity of TGF-β and Hedgehog as possible response predictors to checkpoint inhibition in patients with advanced melanoma; a retrospective cohort study

Abstract Introduction: Although immunotherapy is highly effective in patients with melanoma, not all patients respond equally well to immune checkpoint inhibition (ICI). Preclinical data indicate that TGF-β pathway activity mediates immune evasion by tumor T cell exclusion and may therefore be predictive for response. Recently, a new mRNA-based methodology has been developed to measure and quantify signal transduction pathway (STP) activities in tissue. This study was initiated to characterize the STPs in advanced melanoma samples to better understand the role of STPs in immune check point efficacy. Method: The OncoSIGNal pathway activity profiling PCR test (InnoSIGN) was used to measure the activity of 8 different STPs (AR, PI3K, MAPK, Hedgehog (HH), TGF-β, Notch, NFkB and JAK-STAT1/2) in biopsies (FFPE) from patients with advanced melanoma (n=34) and expressed on a scale from 0 -100. A biopsy of a metastatic site was obtained prior start of ICI therapy (nivolumab or pembrolizumab). These samples were analyzed for STP activity and related to progression-free survival (PFS). Also, STP activities were compared between responders (n=15; partial or complete response) and non-responders (n=19; defined as progression within 6 months). Results: The mean HH score of responders versus non-responders was 35.7 + 6.1 vs 41.6 + 8.7 (p=0.038), while TGF-β scores were 53.9 + 6.2 vs 56.8 + 8.2 (p=0.265), respectively. Cox regression analysis showed a hazard ratio of 1-1.1 for PFS of both HH and TGF-β (HH: p=0.032) (TGF-β: p=0.071). Kaplan Meier curves indicated a better PFS for lower HH activity at a threshold of 46 (p< 0.001) and lower MAPK activity at a threshold of 47.3 (p= 0.041). No relation with PFS was detected for TGF-β activity. No statistically significant differences were observed in STP activity between different metastatic locations ((sub)cutaneous, lymph node or visceral metastases). Conclusion: Signal transduction pathway activity of metastatic samples, taken prior start of ICI therapy, from patients with advanced melanoma, suggest that TGF-β did not correlate with response nor PFS but increased HH and MAPK STP activity may relate towards a worse PFS from ICI therapy. Citation Format: Stefan G. vanRavensteijn, Daniele V. Taurello, Avital Amir, Yvonne J. Wesseling, Anne G. vanBrussel, Diederick M. Keizer, Henk M. Verheul, Kalijn F. Bol. Signal transduction pathway activity of TGF-β and Hedgehog as possible response predictors to checkpoint inhibition in patients with advanced melanoma; a retrospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 958.

Post-Transcriptional Regulatory Crosstalk between MicroRNAs and Canonical TGF-β/BMP Signalling Cascades on Osteoblast Lineage: A Comprehensive Review

MicroRNAs (miRNAs) are a family of small, single-stranded, and non-protein coding RNAs about 19 to 22 nucleotides in length, that have been reported to have important roles in the control of bone development. MiRNAs have a strong influence on osteoblast differentiation through stages of lineage commitment and maturation, as well as via controlling the activities of osteogenic signal transduction pathways. Generally, miRNAs may modulate cell stemness, proliferation, differentiation, and apoptosis by binding the 3'-untranslated regions (3'-UTRs) of the target genes, which then can subsequently undergo messenger RNA (mRNA) degradation or protein translational repression. MiRNAs manage the gene expression in osteogenic differentiation by regulating multiple signalling cascades and essential transcription factors, including the transforming growth factor-beta (TGF-β)/bone morphogenic protein (BMP), Wingless/Int-1(Wnt)/β-catenin, Notch, and Hedgehog signalling pathways; the Runt-related transcription factor 2 (RUNX2); and osterix (Osx). This shows that miRNAs are essential in regulating diverse osteoblast cell functions. TGF-βs and BMPs transduce signals and exert diverse functions in osteoblastogenesis, skeletal development and bone formation, bone homeostasis, and diseases. Herein, we highlighted the current state of in vitro and in vivo research describing miRNA regulation on the canonical TGF-β/BMP signalling, their effects on osteoblast linage, and understand their mechanism of action for the development of possible therapeutics. In this review, particular attention and comprehensive database searches are focused on related works published between the years 2000 to 2022, using the resources from PubMed, Google Scholar, Scopus, and Web of Science.

The Activation of PPARγ by (2Z,4E,6E)-2-methoxyocta-2,4,6-trienoic Acid Counteracts the Epithelial-Mesenchymal Transition Process in Skin Carcinogenesis.

Cutaneous squamous cell carcinoma (cSCC) is the most common UV-induced keratinocyte-derived cancer, and its progression is characterized by the epithelial-mesenchymal transition (EMT) process. We previously demonstrated that PPARγ activation by 2,4,6-octatrienoic acid (Octa) prevents cutaneous UV damage. We investigated the possible role of the PPARγ activators Octa and the new compound (2Z,4E,6E)-2-methoxyocta-2,4,6-trienoic acid (A02) in targeting keratinocyte-derived skin cancer. Like Octa, A02 exerted a protective effect against UVB-induced oxidative stress and DNA damage in NHKs. In the squamous cell carcinoma A431 cells, A02 inhibited cell proliferation and increased differentiation markers' expression. Moreover, Octa and even more A02 counteracted the TGF-β1-dependent increase in mesenchymal markers, intracellular ROS, the activation of EMT-related signal transduction pathways, and cells' migratory capacity. Both compounds, especially A02, counterbalanced the TGF-β1-induced cell membrane lipid remodeling and the release of bioactive lipids involved in EMT. In vivo experiments on a murine model useful to study cell proliferation in adult animals showed the reduction of areas characterized by active cell proliferation in response to A02 topical treatment. In conclusion, targeting PPARγ may be useful for the prevention and treatment of keratinocyte-derived skin cancer.

Sulforaphane suppresses paraquat-induced oxidative damage in bovine in vitro-matured oocytes through Nrf2 transduction pathway

Sulforaphane (SFN), a bioactive phytocompound extracted from cruciferous plants, has received increasing attention due to its vital cytoprotective role in eliminating oxidative free radical through activation of nuclear factor erythroid 2-related factor (Nrf2)-mediated signal transduction pathway. This study aims at a better insight into the protective benefit of SFN in attenuating paraquat (PQ)-caused impairment in bovine in vitro-matured oocytes and the possible mechanisms involved therein. Results showed that addition of 1 μM SFN during oocyte maturation obtained higher proportions of matured oocytes and in vitro-fertilized embryos. SFN application attenuated the toxicological effects of PQ on bovine oocytes, as manifested by enhanced extending capability of cumulus cell and increased extrusion proportion of first polar body. Following incubation with SFN, oocytes exposed to PQ exhibited reduced intracellular ROS and lipid accumulation levels, and elevated T-SOD and GSH contents. SFN also effectively inhibited PQ-mediated increase in BAX and CASPASE-3 protein expressions. Besides, SFN promoted the transcription of NRF2 and its downstream antioxidative-related genes GCLC, GCLM, HO-1, NQO-1, and TXN1 in a PQ-exposed environment, indicating that SFN prevents PQ-caused cytotoxicity through activation of Nrf2 signal transduction pathway. The mechanisms underlying the role of SFN against PQ-induced injury included the inhibition of TXNIP protein and restoration of the global O-GlcNAc level. Collectively, these findings provide novel evidence for the protective role of SFN in alleviating PQ-caused injury, and suggest that SFN application may be an efficacious intervention strategy against PQ cytotoxicity.

Functional estrogen receptor signal transduction pathway activity and antihormonal therapy response in low-grade ovarian carcinoma.

Advanced low-grade ovarian carcinoma (LGOC) is difficult to treat. In several studies, high estrogen receptor (ER) protein expression was observed in patients with LGOC, which suggests that antihormonal therapy (AHT) is a treatment option. However, only a subgroup of patients respond to AHT, and this response cannot be adequately predicted by currently used immunohistochemistry (IHC). A possible explanation is that IHC only takes the ligand, but not the activity, of the whole signal transduction pathway (STP) into account. Therefore, in this study, the authors assessed whether functional STP activity can be an alternative tool to predict response to AHT in LGOC. Tumor tissue samples were obtained from patients with primary or recurrent LGOC who subsequently received AHT. Histoscores of ER and progesterone receptor (PR) were determined. In addition, STP activity of the ER STP and of six other STPs known to play a role in ovarian cancer was assessed and compared with the STP activity of healthy postmenopausal fallopian tube epithelium. Patients who had normal ER STP activity had a progression-free survival (PFS) of 16.1months. This was significantly shorter in patients who had low and very high ER STP activity, with a median PFS of 6.0 and 2.1months, respectively (p<.001). Unlike ER histoscores, PR histoscores were strongly correlated to the ER STP activity and thus to PFS. Aberrant low and very high functional ER STP activity and low PR histoscores in patients with LGOC indicate decreased response to AHT. ER IHC is not representative of functional ER STP activity and is not related to PFS.

The effect of non-surgical periodontal therapy on salivary IL-6 levels in patients with moderate to severe generalized chronic periodontitis.

Generegulation of IL-6 is characterized by the presence of inflammatory cytokines, bacterial products, viral infection, andactivation of the diacylglycerol-, cyclic AMP-, or Ca + + -activated signal transduction pathways. Scaling and root planning (SRP), a non-surgical periodontal therapy, was studied in connection toseveral clinical parameters for its effect on salivary IL-6 levels in patients with generalized chronic periodontitis. For this study, a total of 60 GCP patients were included. Plaque index (PI), gingival index (GI), pocket probing depth (PPD), bleeding on probing percentage (BOP%), and clinical attachment loss were among the clinical indicators covered (CAL). Following SRP, mean IL-6 levels in patients with GCP were significantly higher in the pre-treatment group (2.93 5.17 pg/ml; p 0.05) than in the posttreatmentgroup (5.78 8.26 pg/ml; baseline). Pre- and post-treatment IL-6 levels for PI (pre), BOP percent (pre/post), GI (post), and PPD were found to be positively correlated (post). In patients with GCP, the study showed a statistically significant correlation between periodontal metrics and salivary IL-6. Changes in periodontal indices and IL-6 levels that are statistically significant over time indicate that non-surgicaltreatment is effective, and IL-6 can be regarded as a potent disease activity marker.

Abstract P2-26-02: Valproic acid induces apoptosis and mitochondrial perturbations in breast cancer cells

Abstract Introduction: Breast cancer is the second leading cause of death among women after lung cancer. Despite the increase and improvement in preventive screening, breast cancer still remains a threat, both for pre- and postmenopausal women, due to the rapid development of resistance to drug treatments, which recalls the complicity of multiple factors. Breast cancer prognosis can be correlated with specific histological subtypes and their receptor status. Depending on stage and invasiveness, ER + and PR + breast cancers are treated with surgery and adjuvant chemotherapy, which includes endocrine-based agents, such as SERMS (Tamoxifen), SERDs (Fulvestrant) and aromatase inhibitors (Letrazole and Anastrazole). Resistance to endocrine therapy can be explained by various mechanisms, such as mutations of the estrogen receptor, epigenetic modifications of the same receptor, alterations in hormone synthesis and metabolism, aberrant activation of signaling transduction pathways (up-regulation of PI3K, MAPK, CDKs). To reduce pharmacological resistance, it is possible to use histone deacetylase inhibitors, such as valproic acid, as the epigenetic alterations play an important role in the oncogenesis of breast cancer. Epigenetic modifications of genes are a mechanism used by cancer cells to silence the expression of tumor suppressor genes, driven by epigenetic mutations of regulator factors. The valproic acid, used as an antiepileptic drug and for the treatment of bipolar disorders, is also a selective inhibitor of class I and class II HDAC isoforms, involved in the progression of different types of tumors. In this study, we tested the effects of valproic acid on the signaling involved in apoptosis and in the generation of Reactive Oxygen Species (ROS) in MCF-7 breast cancer cells. Methods: MTT assay was performed to evaluate cell proliferation. Cell cycle, ROS levels and apoptosis were analyzed by flow cytometry, while protein levels were detected by Western Blotting (WB). Results: Cell treatment with valproic acid reduced cell proliferation and induced G0/G1 cell cycle arrest. In addition, the drug enhanced the generation of ROS by the mitochondria and addressed breast cell death by apoptosis. Indeed, the valproic acid was found to downregulate the anti-apoptotic marker Bcl-2 and to upregulate the expression of pro-apoptotic markers, such as Bax and Bad, leading to release of cytochrome C into the cytosol and PARP cleavage. The drastic reduction in mitochondrial membrane potential and in mitochondrial mass was observed following treatment with valproic acid, indeed the ratio between the two parameters, index of functionality per mitochondrion, resulted to be lowered, thus emphasizing the metabolic perturbation in the cells. Conclusion: In summary, our results have demonstrated that in estrogen receptor positive breast cancer cells the valproic acid is a suitable drug to arrest cell growth, to address apoptosis and mitochondrial perturbations, all factors that are important in determining cell fate and health. This study encourages that valproic acid, as an epigenetic drug, is a promising class of antineoplastic agent to be further explored also in combination with other classical chemotherapeutics in breast tumors. Citation Format: Alessandro Paolì, Martina Forestiero, Giuseppina Daniela Naimo, Loredana Mauro, Maria Luisa Panno, Francesca Giordano. Valproic acid induces apoptosis and mitochondrial perturbations in breast cancer cells [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-26-02.

From outside to inside and back again: the lysophosphatidic acid-CCN axis in signal transduction.

CCN1 and CCN2 are matricellular proteins that are transcriptionally induced by various stimuli, including growth factors. CCN proteins act to facilitate signaling events involving extracellular matrix proteins. Lysophosphatidic acid (LPA) is a lipid that activates G protein-coupled receptors (GPCRs), enhancing proliferation, adhesion, and migration in many types of cancer cells. Our group previously reported that LPA induces production of CCN1 protein in human prostate cancer cell lines within 2-4h. In these cells, the mitogenic activity of LPA is mediated by LPA Receptor 1 (LPAR1), a GPCR. There are multiple examples of the induction of CCN proteins by LPA, and by the related lipid mediator sphingosine-1-phosphate (S1P), in various cellular models. The signaling pathways responsible for LPA/S1P-induced CCN1/2 typically involve activation of the small GTP-binding protein Rho and the transcription factor YAP. Inducible CCNs can potentially play roles in downstream signal transduction events required for LPA and S1P-induced responses. Specifically, CCNs secreted into the extracellular space can facilitate the activation of additional receptors and signal transduction pathways, contributing to the biphasic delayed responses typically seen in response to growth factors acting via GPCRs. In some model systems, CCN1 and CCN2 play key roles in LPA/S1P-induced cell migration and proliferation. In this way, an extracellular signal (LPA or S1P) can activate GPCR-mediated intracellular signaling to induce the production of extracellular modulators (CCN1 and CCN2) that in turn initiate another round of intracellular signaling.

MAPK Cascade Signaling Is Involved in α-MMC Induced Growth Inhibition of Multiple Myeloma MM.1S Cells via G2 Arrest and Mitochondrial-Pathway-Dependent Apoptosis In Vitro

Multiple myeloma is a hematological malignancy characterized by the unrestricted proliferation of plasma cells that secrete monoclonal immunoglobulins in the bone marrow. Alpha-momorcharin (α-MMC) is a type I ribosome-inactivating protein extracted from the seeds of the edible plant Momordica charantia L., which has a variety of biological activities. This study aimed to investigate the inhibitory effect of α-MMC on the proliferation of multiple myeloma MM.1S cells and the molecular mechanism of MM.1S cell death induced through the activation of cell signal transduction pathways. The cell counting kit-8 (CCK-8) assay was used to determine the inhibitory effect of α-MMC on the proliferation of MM.1S cells and its toxic effect on normal human peripheral blood mononuclear cells (PBMCs). The effect of α-MMC on the MM.1S cells' morphology was observed via inverted microscope imaging. The effects of α-MMC on the MM.1S cell cycle, mitochondrial membrane potential (MMP), and apoptosis were explored using propidium iodide, JC-1, annexin V- fluorescein isothiocyanate/propidium iodide fluorescence staining, and flow cytometry (FCM) analysis. Western blot was used to detect the expressions levels of apoptosis-related proteins and MAPK-signaling-pathway-related proteins in MM.1S cells induced by α-MMC. The results of the CCK-8 showed that in the concentration range of no significant toxicity to PBMCs, α-MMC inhibited the proliferation of MM.1S cells in a time-dependent and concentration-dependent manner, and the IC50 value was 13.04 and 7.518 μg/mL for 24 and 48 h, respectively. Through inverted microscope imaging, it was observed that α-MMC induced a typical apoptotic morphology in MM.1S cells. The results of the FCM detection and analysis showed that α-MMC could arrest the MM.1S cells cycle at the G2 phase, decrease the MMP, and induce cell apoptosis. Western blot analysis found that α-MMC upregulated the expression levels of Bax, Bid, cleaved caspase-3, and cleaved PARP, and downregulated the expression levels of Mcl-1. At the same time, α-MMC decreased the expression levels of p-c-Raf, p-MEK1/2, p-ERK1/2, p-MSK1, and p-P90RSK, and increased the expression levels of p-p38, p-SPAK/JNK, p-c-Jun, and p-ATF2. The above results suggest that α-MMC can inhibit the proliferation of multiple myeloma MM.1S cells. MAPK cascade signaling is involved in the growth inhibition effect of α-MMC on MM.1S cells via cycle arrest and mitochondrial-pathway-dependent apoptosis.