Activation of the Protein Kinase B (PKB), or AKT pathway has been shown to correlate with acute myeloid leukemia (AML) prognosis. B55α-Protein Phosphatase 2A (PP2A) has been shown to dephosphorylate AKT at Thr-308 rendering it inactive. In fact, low expression of the PP2A regulatory subunit B55α was associated with activated phospho-AKT and correlated with inferior outcomes in AML. Despite this fact, no studies have specifically demonstrated a mechanism whereby B55α expression is regulated in AML. In this study, we demonstrate novel loss of function mutations in the PPP2R2A gene identified in leukemic blasts from three AML patients. These mutations eliminate B55α protein expression thereby allowing constitutive AKT activation. In addition, leukemic blasts with PPP2R2A gene mutation were more sensitive to treatment with the AKT inhibitor MK2206, but less responsive to the PP2A activator FTY720. Using leukemia cell lines, we further demonstrate that B55α expression correlates with AKT Thr-308 phosphorylation and predicts responsiveness to AKT inhibition and PP2A activation. Together our data illustrate the importance of the B55α-PP2A-AKT pathway in leukemogenesis. Screening for disruptions in this pathway at initial AML diagnosis may predict response to targeted therapies against AKT and PP2A.

Background

Survivin is expressed in prostate cancer (PCa), and its downregulation sensitizes PCa cells to chemotherapeutic agents in vitro and in vivo. Small membrane-bound vesicles called exosomes, secreted from the endosomal membrane compartment, contain RNA and protein that they readily transport via exosome internalization into recipient cells. Recent progress has shown that tumor-derived exosomes play multiple roles in tumor growth and metastasis and may produce these functions via immune escape, tumor invasion and angiogenesis. Furthermore, exosome analysis may provide novel biomarkers to diagnose or monitor PCa treatment.

Methods

Exosomes were purified from the plasma and serum from 39 PCa patients, 20 BPH patients, 8 prostate cancer recurrent and 16 healthy controls using ultracentrifugation and their quantities and qualities were quantified and visualized from both the plasma and the purified exosomes using ELISA and Western blotting, respectively.

Results

Survivin was significantly increased in the tumor-derived samples, compared to those from BPH and controls with virtually no difference in the quantity of Survivin detected in exosomes collected from newly diagnosed patients exhibiting low (six) or high (nine) Gleason scores. Exosome Survivin levels were also higher in patients that had relapsed on chemotherapy compared to controls.

Conclusions

These studies demonstrate that Survivin exists in plasma exosomes from both normal, BPH and PCa subjects. The relative amounts of exosomal Survivin in PCa plasma was significantly higher than in those with pre-inflammatory BPH and control plasma. This differential expression of exosomal Survivin was seen with both newly diagnosed and advanced PCa subjects with high or low-grade cancers. Analysis of plasma exosomal Survivin levels may offer a convenient tool for diagnosing or monitoring PCa and may, as it is elevated in low as well as high Gleason scored samples, be used for early detection.

Abstract Background We have evaluated an attenuated Listeria monocytogenes (Lm) candidate vaccine vector in nonhuman primates using a delivery regimen relying solely on oral vaccination. We sought to determine the impact of prior Lm vector exposure on the development of new immune responses against HIV antigens. Findings Two groups of rhesus macaques one Lm naive, the other having documented prior Lm vector exposures, were evaluated in response to oral inoculations of the same vector expressing recombinant HIV-1 Gag protein. The efficacy of the Lm vector was determined by ELISA to assess the generation of anti-Listerial antibodies; cellular responses were measured by HIV-Gag specific ELISpot assay. Our results show that prior Lm exposures did not diminish the generation of de novo cellular responses against HIV, as compared to Listeria-naïve monkeys. Moreover, empty vector exposures did not elicit potent antibody responses, consistent with the intracellular nature of Lm. Conclusions The present study demonstrates in a pre-clinical vaccine model, that prior oral immunization with an empty Lm vector does not diminish immunogenicity to Lm-expressed HIV genes. This work underscores the need for the continued development of attenuated Lm as an orally deliverable vaccine.

In the past decade, targeted therapies for solid tumors, including non-small cell lung cancer (NSCLC), have advanced significantly, offering tailored treatment options for patients. However, individuals without targetable mutations pose a clinical challenge, as they may not respond to standard treatments like immune-checkpoint inhibitors (ICIs) and novel targeted therapies. While the mechanism of action of ICIs seems promising, the lack of a robust response limits their widespread use. Although the expression levels of programmed death ligand 1 (PD-L1) on tumor cells are used to predict ICI response, identifying new biomarkers, particularly those associated with the tumor microenvironment (TME), is crucial to address this unmet need. Recently, inflammatory cytokines such as interleukin-1 beta (IL-1β) have emerged as a key area of focus and hold significant potential implications for future clinical practice. Combinatorial approaches of IL-1β inhibitors and ICIs may provide a potential therapeutic modality for NSCLC patients without targetable mutations. Recent advancements in our understanding of the intricate relationship between inflammation and oncogenesis, particularly involving the IL-1β/PD-1/PD-L1 pathway, have shed light on their application in lung cancer development and clinical outcomes of patients. Targeting these pathways in cancers like NSCLC holds immense potential to revolutionize cancer treatment, particularly for patients lacking targetable genetic mutations. However, despite these promising prospects, there remain certain aspects of this pathway that require further investigation, particularly regarding treatment resistance. Therefore, the objective of this review is to delve into the role of IL-1β in NSCLC, its participation in inflammatory pathways, and its intricate crosstalk with the PD-1/PD-L1 pathway. Additionally, we aim to explore the potential of IL-1β as a therapeutic target for NSCLC treatment.