Establishment of canine mammary gland tumor cell lines harboring PI3K/Akt activation as a therapeutic target.

Canine mammary gland tumors (MGT) have a poor prognosis in intact female canines, posing a clinical challenge. This study aimed to establish novel canine mammary cancer cell lines from primary tumors and characterize their cellular and molecular features to find potential therapeutic drugs. The MGT cell lines demonstrated rapid cell proliferation and colony formation in an anchorage-independent manner. Vimentin and α-SMA levels were significantly elevated in MGT cell lines compared to normal canine kidney (MDCK) cells, while CDH1 expression was either significantly lower or not detected at all, based on quantitative real-time PCR (qRT-PCR) analysis. Functional annotation and enrichment analysis revealed that epithelial-mesenchymal transition (EMT) phenotypes and tumor-associated pathways, particularly the PI3K/Akt signaling pathway, were upregulated in MGT cells. BYL719 (Alpelisib), a PI3K inhibitor, was also examined for cytotoxicity on the MGT cell lines. The results show that BYL719 can significantly inhibit the proliferation of MGT cell lines in vitro. Overall, our findings suggest that the MGT cell lines may be valuable for future studies on the development, progression, metastasis, and management of tumors.

PI3K/mTOR inhibition induces tumour microenvironment remodelling and sensitises pS6high uterine leiomyosarcoma to PD-1 blockade.

BACKGROUND: Uterine leiomyosarcomas (uLMS) are aggressive tumours with poor prognosis and limited treatment options. Although immune checkpoint blockade (ICB) has proven effective in some 'challenging-to-treat' cancers, clinical trials showed that uLMS do not respond to ICB. Emerging evidence suggests that aberrant PI3K/mTOR signalling can drive resistance to ICB. We therefore explored the relevance of the PI3K/mTOR pathway for ICB treatment in uLMS and explored pharmacological inhibition of this pathway to sensitise these tumours to ICB. METHODS: We performed an integrated multiomics analysis based on TCGA data to explore the correlation between PI3K/mTOR dysregulation and immune infiltration in 101 LMS. We assessed response to PI3K/mTOR inhibitors in immunodeficient and humanized uLMS patient-derived xenografts (PDXs) by evaluating tumour microenvironment modulation using multiplex immunofluorescence. We explored response to single-agent and a combination of PI3K/mTOR inhibitors with PD-1 blockade in humanized uLMS PDXs. We mapped intratumoural dynamics using single-cell RNA/TCR sequencing of serially collected biopsies. RESULTS: PI3K/mTOR over-activation (pS6high) associated with lymphocyte depletion and wound healing immune landscapes in (u)LMS, suggesting it contributes to immune evasion. In contrast, PI3K/mTOR inhibition induced profound tumour microenvironment remodelling in an ICB-resistant humanized uLMS PDX model, fostering adaptive anti-tumour immune responses. Indeed, PI3K/mTOR inhibition induced macrophage repolarisation towards an anti-tumourigenic phenotype and increased antigen presentation on dendritic and tumour cells, but also promoted infiltration of PD-1+ T cells displaying an exhausted phenotype. When combined with anti-PD-1, PI3K/mTOR inhibition led to partial or complete tumour responses, whereas no response to single-agent anti-PD-1 was observed. Combination therapy reinvigorated exhausted T cells and induced clonal hyper-expansion of a cytotoxic CD8+ T-cell population supported by a CD4+ Th1 niche. CONCLUSIONS: Our findings indicate that aberrant PI3K/mTOR pathway activation contributes to immune escape in uLMS and provides a rationale for combining PI3K/mTOR inhibition with ICB for the treatment of this patient population.

EGFR and PI3K Signalling Pathways as Promising Targets on Circulating Tumour Cells from Patients with Metastatic Gastric Adenocarcinoma.

The prognosis for metastatic gastric adenocarcinoma (mGAC) remains poor. Gene alterations in receptor tyrosine kinases (RTKs) such as epidermal growth factor receptor (EGFR) and their downstream effectors including catalytic subunit alpha of the phosphatidylinositol 3-kinase (PIK3CA) are common in mGAC. Targeted RTK and phosphatidylinositol-3-kinase (PI3K) treatments have demonstrated clinical benefits in other solid tumours and are key potential targets for clinical development against mGAC given the presence of recurrent alterations in these pathways. Furthermore, combination RTK/PI3K treatments may overcome compensatory mechanisms that arise using monotherapies, leading to improved patient outcomes. Herein, we investigated RTK/PI3K single and combination drug responses against our unique human mGAC-derived PIK3CA gain-of-function mutant, human epidermal growth factor receptor 2 (HER2)-negative, EGFR-expressing circulating tumour cell line, UWG02CTC, under two- and three-dimensional culture conditions to model different stages of metastasis. UWG02CTCs were highly responsive to the PI3K p110α-subunit targeted drugs PIK-75 (IC50 = 37.0 ± 11.1 nM) or alpelisib (7.05 ± 3.7 µM). Drug sensitivities were significantly increased in 3D conditions. Compensatory MAPK/ERK pathway upregulation by PI3K/Akt suppression was overcome by combination treatment with the EGFR inhibitor gefitinib, which was strongly synergistic. PIK-75 plus gefitinib significantly impaired UWG02CTC invasion in an organotypic assay. In conclusion, UWG02CTCs are a powerful ex vivo mGAC drug responsiveness model revealing EGFR/PI3K-targeted drugs as a promising combination treatment option for HER2-negative, RAS wild-type mGAC patients.

ABCG2 Mediates Resistance to the Dual EGFR and PI3K Inhibitor MTX-211 in Cancer Cells.

MTX-211 is a first-in-class dual inhibitor of epidermal growth factor receptor (EGFR) and phosphoinositide-3 kinase (PI3K) signaling pathways with a compelling pharmaceutical profile and could enhance the effectiveness of mitogen-activated protein kinase kinase (MEK) inhibitor therapy in colorectal tumors with KRAS mutations. However, the specific mechanisms contributing to the acquired resistance to MTX-211 in human cancers remain elusive. Here, we discovered that the overexpression of the ATP-binding cassette (ABC) drug transporter ABCG2, a prevalent mechanism associated with multidrug resistance (MDR), could diminish the effectiveness of MTX-211 in human cancer cells. We showed that the drug efflux activity of ABCG2 substantially decreased the intracellular accumulation of MTX-211 in cancer cells. As a result, the cytotoxicity and effectiveness of MTX-211 in suppressing the activation of the EGFR and PI3K pathways were significantly attenuated in cancer cells overexpressing ABCG2. Moreover, the enhancement of the MTX-211-stimulated ATPase activity of ABCG2 and the computational molecular docking analysis illustrating the binding of MTX-211 to the substrate-binding sites of ABCG2 offered a further indication for the interaction between MTX-211 and ABCG2. In summary, our findings indicate that MTX-211 acts as a substrate for ABCG2, underscoring the involvement of ABCG2 in the emergence of resistance to MTX-211. This finding carries clinical implications and merits further exploration.

TYM-3-98, a novel selective inhibitor of PI3Kδ, demonstrates promising preclinical antitumor activity in B-cell lymphomas.

AIMS: PI3Kδ is expressed predominately in leukocytes and is commonly found to be aberrantly activated in human B-cell lymphomas. Although PI3Kδ has been intensively targeted for discovering anti-lymphoma drugs, the application of currently approved PI3Kδ inhibitors has been limited due to unwanted systemic toxicities, thus warranting the development of novel PI3Kδ inhibitors with new scaffolds. MAIN METHODS: We designed TYM-3-98, an indazole derivative, and evaluated its selectivity for all four PI3K isoforms, as well as its efficacy against various B-cell lymphomas both in vitro and in vivo. KEY FINDINGS: We identified TYM-3-98 as a highly selective PI3Kδ inhibitor over other PI3K isoforms at both molecular and cellular levels. It showed superior antiproliferative activity in several B-lymphoma cell lines compared with the approved first-generation PI3Kδ inhibitor idelalisib. TYM-3-98 demonstrated a concentration-dependent PI3K/AKT/mTOR signaling blockage followed by apoptosis induction. In vivo, TYM-3-98 showed good pharmaceutical properties and remarkably reduced tumor growth in a human lymphoma xenograft model and a mouse lymphoma model. SIGNIFICANCE: Our findings establish TYM-3-98 as a promising PI3Kδ inhibitor for the treatment of B-cell lymphoma.

Lactobacillus rhamnosus HN001 facilitates the efficacy of dual PI3K/mTOR inhibition prolonging cardiac transplant survival and enhancing antitumor effect.

Solid organ transplantation is a crucial treatment for patients who have reached the end stage of heart, lung, kidney, or liver failure. However, the likelihood of developing cancer post-transplantation increases. Additionally, primary malignant tumors remain a major obstacle to the long-term survival of transplanted organs. Therefore, it is essential to investigate effective therapies that can boost the immune system's ability to combat cancer and prevent allograft rejection. We established a mouse orthotopic liver tumor model and conducted allogeneic heterotopic heart transplantation. Various treatments were administered, and survival curves were generated using the Kaplan-Meier method. We also collected graft samples and measured inflammatory cytokine levels in the serum using an inflammatory array. The specificity of the histochemical techniques was tested by staining sections. We administered a combination therapy of phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) dual inhibitor BEZ235 and Lactobacillus rhamnosus HN001 to primary liver cancer model mice with cardiac allografts. Consistent with our prior findings, L. rhamnosus HN001 alleviated the intestinal flora imbalance caused by BEZ235. Our previous research confirmed that the combination of BEZ235 and L. rhamnosus HN001 significantly prolonged cardiac transplant survival. IMPORTANCE: We observed that the combination of phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) dual inhibitor BEZ235 and Lactobacillus rhamnosus HN001 notably prolonged cardiac transplant survival while also inhibiting the progression of primary liver cancer. The combination therapy was efficacious in treating antitumor immunity and allograft rejection, as demonstrated by the efficacy results. We also found that this phenomenon was accompanied by the regulation of inflammatory IL-6 expression. Our study presents a novel and effective therapeutic approach to address antitumor immunity and prevent allograft rejection.

Curcumin Alone and Combined With PI3K Inhibitors Elicits Positive Effects on Oropharyngeal Cancer Cell Lines Regardless of HPV Status.

BACKGROUND/AIM: Human papillomavirus positive (HPV+) oropharyngeal squamous cell carcinoma (OPSCC) is rising in incidence. Compared to HPV-negative (HPV-) OPSCC, HPV+ cases have a better 5-year survival. With its severe side-effects, today's chemoradiotherapy has not improved outcome compared to radiotherapy alone, so new therapies are needed. Mutations in phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), fibroblast growth factor receptor 3 (FGFR3) and cell division cycle 27 (CDC27) are found in HPV+ OPSCC, and in vitro targeted therapy combining PI3K and FGFR inhibitors showed synergistic effects. Here the effects of targeting CDC27 with curcumin with/without various inhibitors or cisplatin on OPSCC cell lines were examined. MATERIALS AND METHODS: Curcumin was administered to HPV+ OPSCC cell lines CU-OP-2, CU-OP-3 and CU-OP-20, and HPV- CU-OP-17 with/without PI3K, cyclin-dependent kinase 4/6, FGFR, poly (ADP-ribose) polymerase or WEE1 inhibitors (BYL719, PD-0332991, JNJ-42756493, BMN-673 and MK-1775, respectively), or cisplatin. The cell lines were then assessed for 72 h after treatment for viability, proliferation and cytotoxicity. RESULTS: Curcumin led to dose-dependent responses with reduced viability and proliferation; upon combining it with BYL719, additional positive effects were found for most OPSCC lines grown as monolayers, and these effects were validated in CU-OP-2 cells grown as spheroids. Curcumin with MK-1775 or PD-0332991 also elicited some positive effects on CU-OP-2 and CU-OP-17 cells. CONCLUSION: Curcumin alone led to dose-dependent responses and when combined with BYL719, positive effects were revealed, as they were when it was combined with MK-1775 or PD-0332991, suggesting a potential use of some of these combinations for HPV+ OPSCC.

PUMC-MB1 is a novel group 3 medulloblastoma preclinical model, sensitive to PI3K/mTOR dual inhibitor.

PURPOSE: Medulloblastoma (MB), a common and heterogeneous posterior fossa tumor in pediatric patients, presents diverse prognostic outcomes. To advance our understanding of MB's intricate biology, the development of novel patient tumor-derived culture MB models with necessary data is still an essential requirement. METHODS: We continuously passaged PUMC-MB1 in vitro in order to establish a continuous cell line. We examined the in vitro growth using Cell Counting Kit-8 (CCK-8) and in vivo growth with subcutaneous and intracranial xenograft models. The xenografts were investigated histopathologically with Hematoxylin and Eosin (HE) staining and immunohistochemistry (IHC). Concurrently, we explored its molecular features using Whole Genome Sequencing (WGS), targeted sequencing, and RNA sequecing. Guided by bioinformatics analysis, we validated PUMC-MB1's drug sensitivity in vitro and in vivo. RESULTS: PUMC-MB1, derived from a high-risk MB patient, displayed a population doubling time (PDT) of 48.18 h and achieved 100% tumor growth in SCID mice within 20 days. HE and Immunohistochemical examination of the original tumor and xenografts confirmed the classification of PUMC-MB1 as a classic MB. Genomic analysis via WGS revealed concurrent MYC and OTX2 amplifications. The RNA-seq data classified it within the Group 3 MB subgroup, while according to the WHO classification, it fell under the Non-WNT/Non-SHH MB. Comparative analysis with D283 and D341med identified 4065 differentially expressed genes, with notable enrichment in the PI3K-AKT pathway. Cisplatin, 4-hydroperoxy cyclophosphamide/cyclophosphamide, vincristine, and dactolisib (a selective PI3K/mTOR dual inhibitor) significantly inhibited PUMC-MB1 proliferation in vitro and in vivo. CONCLUSIONS: PUMC-MB1, a novel Group 3 (Non-WNT/Non-SHH) MB cell line, is comprehensively characterized for its growth, pathology, and molecular characteristics. Notably, dactolisib demonstrated potent anti-proliferative effects with minimal toxicity, promising a potential therapeutic avenue. PUMC-MB1 could serve as a valuable tool for unraveling MB mechanisms and innovative treatment strategies.

Targeting the PI3K/AKT signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023).

INTRODUCTION: Recent years have witnessed great achievements in drug design and development targeting the phosphatidylinositol 3-kinase/protein kinase-B (PI3K/AKT) signaling pathway, a pathway central to cell growth and proliferation. The nearest neighbor protein-protein interaction networks for PI3K and AKT show the interplays between these target proteins which can be harnessed for drug discovery. In this review, we discuss the drug design and clinical development of inhibitors of PI3K/AKT in the past three years. We review in detail the structures, selectivity, efficacy, and combination therapy of 35 inhibitors targeting these proteins, classified based on the target proteins. Approaches to overcoming drug resistance and to minimizing toxicities are discussed. Future research directions for developing combinational therapy and PROTACs of PI3K and AKT inhibitors are also discussed. AREA COVERED: This review covers clinical trial reports and patent literature on inhibitors of PI3K and AKT published between 2020 and 2023. EXPERT OPINION: To address drug resistance and drug toxicity of inhibitors of PI3K and AKT, it is highly desirable to design and develop subtype-selective PI3K inhibitors or subtype-selective AKT1 inhibitors to minimize toxicity or to develop allosteric drugs that can form covalent bonds. The development of PROTACs of PI3Kα or AKT helps to reduce off-target toxicities.

Learnings from phosphatidylinositol 3-kinase inhibitors in lymphoma-Moving to a model where less can be more.

The role of Pi3K inhibitors in lymphoma is diminishing due to the adverse results from trials in indolent lymphoma, but is a one-size-fits-all approach to drug development penalising some lymphoma subtypes and the newer generation of Pi3K inhibitors? The report by Soumerai et al. of zandelisib with zanubrutinib in follicular and mantle cell lymphoma is an important addition to the data. Commentary on: Soumerai et al. Safety and efficacy of zandelisib plus zanubrutinib in previously treated follicular and mantle cell lymphomas. Br J Haematol 2024;204:1762-1770.

Inhibition of PI3K p110δ rebalanced Th17/Treg and reduced macrophages pyroptosis in LPS-induced sepsis.

Sepsis is a systemic inflammatory response syndrome caused by trauma or infection, which can lead to multiple organ dysfunction. In severe cases, sepsis can also progress to septic shock and even death. Effective treatments for sepsis are still under development. This study aimed to determine if targeting the PI3K/Akt signaling with CAL-101, a PI3K p110δ inhibitor, could alleviate lipopolysaccharide (LPS)-induced sepsis and contribute to immune tolerance. Our findings indicated that CAL-101 treatment improved survival rates and alleviated the progression of LPS-induced sepsis. Compared to antibiotics, CAL-101 not only restored the Th17/regulatory T cells (Treg) balance but also enhanced Treg cell function. Additionally, CAL-101 promoted type 2 macrophage (M2) polarization, inhibited TNF-α secretion, and increased IL-10 secretion. Moreover, CAL-101 treatment reduced pyroptosis in peritoneal macrophages by inhibiting caspase-1/gasdermin D (GSDMD) activation. This study provides a mechanistic basis for future clinical exploration of targeted therapeutics and immunomodulatory strategies in the treatment of sepsis.

Strategies and techniques for preclinical therapeutic targeting of PI3K in oncology: where do we stand in 2024?

INTRODUCTION: The PI3K/AKT/mTOR signaling pathway is an important signaling pathway in eukaryotic cells that is activated in a variety of cancers and is also associated with treatment resistance. This signaling pathway is an important target for anticancer therapy and holds great promise for research. At the same time PI3K inhibitors have a general problem that they have unavoidable toxic side effects. AREAS COVERED: This review provides an explanation of the role of PI3K in the development and progression of cancer, including several important mutations, and a table listing the cancers caused by these mutations. We discuss the current landscape of PI3K inhibitors in preclinical and clinical trials, address the mechanisms of resistance to PI3K inhibition along with their associated toxic effects, and highlight significant advancements in preclinical research of this field. Furthermore, based on our study and comprehension of PI3K, we provide a recapitulation of the key lessons learned from the research process and propose potential measures for improvement that could prove valuable. EXPERT OPINION: The PI3K pathway is a biological pathway of great potential value. However, the reduction of its toxic side effects and combination therapies need to be further investigated.

PI3Kγδ inhibition suppresses key disease features in a rat model of asthma.

BACKGROUND: Two isoforms of Phosphoinositide 3-kinase (PI3K), p110γ and p110δ, are predominantly expressed in leukocytes and represent attractive therapeutic targets for the treatment of allergic asthma. The study aim was to assess the impact of administration of an inhaled PI3Kγδ inhibitor (AZD8154) in a rat model of asthma. METHODS: Firstly, we checked that the tool compound, AZD8154, inhibited rat PI3K γ & δ kinases using rat cell-based assays. Subsequently, a time-course study was conducted in a rat model of asthma to assess PI3K activity in the lung and how it is temporally associated with other key transcription pathways and asthma like features of the model. Finally, the impact on lung dosed AZD8154 on target engagement, pathway specificity, airway inflammation and lung function changes was assessed. RESULTS: Data showed that AZD8154 could inhibit rat PI3K γ & δ isoforms and, in a rat model of allergic asthma the PI3K pathway was activated in the lung. Intratracheal administration of AZD8154 caused a dose related suppression PI3K pathway activation (reduction in pAkt) and unlike after budesonide treatment, STAT and NF-κB pathways were not affected by AZD8154. The suppression of the PI3K pathway led to a marked inhibition of airway inflammation and reduction in changes in lung function. CONCLUSION: These data show that a dual PI3Kγδ inhibitor suppress key features of disease in a rat model of asthma to a similar degree as budesonide and indicate that dual PI3Kγδ inhibition may be an effective treatment for people suffering from allergic asthma.

PI3Kδ and mTOR dual inhibitors: Design, synthesis and anticancer evaluation of 3-substituted aminomethylquinoline analogues.

Phosphatidylinositide-3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) have recently been identified as potential cancer targets. In our work, a new family of quinoline analogues was designed, developed, and evaluated as dual inhibitors of PI3Kδ/mTOR. The preliminary biological activity analysis led to the discovery of the lead compounds 5h and 5e. Compounds 5h and 5e exhibited excellent anti-tumor potency with IC50 of 0.26 µM and 0.34 µM against Ramos cells, respectively. Importantly, based on the enzymatic activity assay results, compounds 5h and 5e were identified as dual inhibitors of PI3Kδ and mTOR, with IC50 values of 0.042 µM and 0.056 µM for PI3Kδ and 0.059 µM and 0.073 µM for mTOR, respectively. Furthermore, these compounds showed superior selectivity for blocking PI3Kδ compared to other PI3K isoforms (α, ß, and γ), supporting the concept of developing inhibitors that specifically target PI3Kδ/mTOR. The most effective compound 5h was chosen for additional biological testing. At a low dose of 0.5 µM, a western blot investigation confirmed the anticancer effects by inhibiting the PAM cascade, which in turn reduced downstream biomarkers pAkt (Ser473), pAkt (Thr308), and pRPS6 (Ser235/236). Furthermore, it increased apoptosis at the early (10.03 times) and late (17.95 times) stages in the Annexin-V assay as compared to the standard. In addition, the expression of p53, caspase-3, caspase-9, and the Bax/BCl-2 ratio were all significantly increased by compound 5h in the ELISA assay. Based on these results, it appears that 5h may activate the intrinsic apoptosis pathway, which in turn triggers cell death. Furthermore, the anticancer effects could be attributed to the inhibition of PI3Kδ/mTOR, as shown by docking interactions. Lastly, it demonstrated improved in vitro metabolic stability and passed the in silico ADMET/drug-likeness test. This profile recommends 5h for future in vivo PK-PD and efficacy investigations in animal cancer models.

The PI3K/AKT/mTOR signaling pathway in breast cancer: Review of clinical trials and latest advances.

Breast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer mortality in women. As the phosphatidylinositol 3-kinase (PI3K) signaling pathway is involved in a wide range of physiological functions of cells including growth, proliferation, motility, and angiogenesis, any alteration in this axis could induce oncogenic features; therefore, numerous preclinical and clinical studies assessed agents able to inhibit the components of this pathway in BC patients. To the best of our knowledge, this is the first study that analyzed all the registered clinical trials investigating safety and efficacy of the PI3K/AKT/mTOR axis inhibitors in BC. Of note, we found that the trends of PI3K inhibitors in recent years were superior as compared with the inhibitors of either AKT or mTOR. However, most of the trials entering phase III and IV used mTOR inhibitors (majorly Everolimus) followed by PI3K inhibitors (majorly Alpelisib) leading to the FDA approval of these drugs in the BC context. Despite favorable efficacies, our analysis shows that the majority of trials are utilizing PI3K pathway inhibitors in combination with hormone therapy and chemotherapy; implying monotherapy cannot yield huge clinical benefits, at least partly, due to the activation of compensatory mechanisms. To emphasize the beneficial effects of these inhibitors in combined-modal strategies, we also reviewed recent studies which investigated the conjugation of nanocarriers with PI3K inhibitors to reduce harmful toxicities, increase the local concentration, and improve their efficacies in the context of BC therapy.

Discovery of Potent and Selective PI3Kδ Inhibitors for the Treatment of Acute Myeloid Leukemia.

PI3Kδ is an essential target correlated to the occurrence and development of acute myeloid leukemia (AML). Herein, we investigated the pyrazolo[3,4-d]pyrimidine derivatives as potent and selective PI3Kδ inhibitors with high therapeutic efficacy toward AML. There were 44 compounds designed and prepared in a four-round optimization, and the biological evaluation showed that (S)-36 exhibited potent PI3Kδ inhibitory activity, high selectivity, and high antiproliferative activities against MV-4-11 and MOLM-13 cells, coupled with high oral bioavailability (F = 59.6%). In the MOLM-13 subcutaneous xenograft model, (S)-36 could significantly suppress the tumor progression with a TGI of 67.81% at an oral administration dosage of 10 mg/kg without exhibiting obvious toxicity. Mechanistically, (S)-36 could robustly inhibit the PI3K/AKT pathway for significant suppression of cell proliferation and remarkable induction of apoptosis both in vitro and in vivo. Thus, compound (S)-36 represents a promising PI3Kδ inhibitor for the treatment of acute myeloid leukemia with high efficacy.

Inhibition of PI3K/AKT signaling using BKM120 reduced the proliferation and migration potentials of colorectal cancer cells and enhanced cisplatin-induced cytotoxicity.

BACKGROUND: Although extensive efforts have been made to improve the treatment of colorectal cancer (CRC) patients, the prognosis for these patients remains poor. A wide range of anti-cancer agents has been applied to ameliorate the clinical management of CRC patients; however, drug resistance develops in nearly all patients. Based on the prominent role of PI3K/AKT signaling in the development of CRC and current interest in the application of PI3K inhibitors, we aimed to disclose the exact mechanism underlying the efficacy of BKM120, a well-known pan-class I PI3K inhibitor, in CRC-derived SW480 cells. MATERIALS AND METHODS: The effects of BKM120 on SW480 cells were studied using MTT assay, cell cycle assay, Annexin V/PI apoptosis tests, and scratch assay. In the next step, qRT-PCR was used to investigate the underlying molecular mechanisms by which the PI3K inhibitor could suppress the survival of SW480 cells. RESULT: The results of the MTT assay showed that BKM120 could decrease the metabolic activity of SW480 cells in a concentration and time-dependent manner. Investigating the exact mechanism of BKM120 showed that this PI3K inhibitor induces its anti-survival effects through a G2/M cell cycle arrest and apoptosis-mediated cell death. Moreover, the scratch assay demonstrated that PI3K inhibition led to the inhibition of cancer invasion and inhibition of PI3K/AKT signaling remarkably sensitized SW480 cells to Cisplatin. CONCLUSION: Based on our results, inhibition of PI3K/AKT signaling can be a promising approach, either as a single modality or in combination with Cisplatin. However, further clinical studies should be performed to improve our understanding.

PI3K and tankyrase inhibitors as therapeutic targets in colorectal cancer.

INTRODUCTION: The pathways like Wingless-related integration (Wnt/ß-catenin) and PI3K play an important role in colorectal cancer (CRC) development; however, their roles are distinct in the process of oncogenesis. Despite their differences, these pathways interact through feedback mechanisms and regulate the common effectors both in the upstream and the downstream processes in normal and pathological conditions. Their ability to reciprocally control each other is a primary resistance mechanism for the selective inhibitors in CRC. AREA COVERED: This review highlights the Wnt/ß-catenin and PI3K pathways that are interrelated in CRC, recent advances and some key perspectives in developing inhibitors that could target the tankyrase enzyme and PI3K, apart from a brief description of the potential of dual inhibitors of PI3K and Tankyrases (TNKS). EXPERT OPINION: Recent research has focused on overcoming the challenges particularly relating to the resistance and efficacy of dual inhibitors targeting PI3K and tankyrase proteins. Despite these challenges, PI3K as well as tankyrases remain promising therapeutic targets for the treatment of solid tumors. The design of potent inhibitors is crucial to effectively block these protein signaling pathways. Moreover, it is essential to explore the potential of dual-target inhibition of other signaling pathways in conjunction with PI3K and tankyrase.

PI3Kα inhibitor GNE-493 triggers antitumor immunity in murine lung cancer by inducing immunogenic cell death and activating T cells.

Phosphatidylinositol 3-kinase (PI3K) is frequently hyperactivated in cancer, playing pivotal roles in the pathophysiology of both malignant and immune cells. The impact of PI3K inhibitors on the tumor microenvironment (TME) within lung cancer remains largely unknown. In this study, we explored the regulatory effects of GNE-493, an innovative dual inhibitor of PI3K and mammalian target of rapamycin (mTOR), on the TME of lung cancer. First, through the analysis of The Cancer Genome Atlas-lung squamous cell carcinoma (LUSC) cohort, we found PIK3CA to be related to CD8 T cells, which may affect the overall survival rate of patients by affecting CD8 function. We herein demonstrated that GNE-493 can significantly inhibit tumor cell proliferation and promote cell apoptosis while increasing the expression of the immunogenic death-related molecules CRT and HSP70 using in vitro cell proliferation and apoptosis experiments on the murine KP lung cancer cell line and human A549 lung cancer cell line. Next, through the establishment of an orthotopic tumor model in vivo, it was found that after GNE-493 intervention, the infiltration of CD4+ and CD8+ T cells in mouse lung tumor was significantly increased, and the expression of CRT in tumors could be induced to increase. To explore the mechanisms underlying PI3K inhibition-induced changes in the TME, the gene expression differences of T cells in the control group versus GNE-493-treated KP tumors were analyzed by RNA-seq, and the main effector pathway of anti-tumor immunity was identified. The IFN/TNF family molecules were significantly upregulated after GNE-493 treatment. In summary, our findings indicate that GNE-493 promotes immunogenic cell death in lung cancer cells, and elucidates its regulatory impact on molecules associated with the adaptive immune response. Our study provides novel insights into how PI3K/mTOR inhibitors exert their activity by modulating the tumor-immune interaction.