Blockade of PI3K/AKT pathway enhances sensitivity of Raji cells to chemotherapy through down-regulation of HSP70

Functionalized Nanomaterials for Inhibiting ATP-Dependent Heat Shock Proteins in Cancer Photothermal/Photodynamic Therapy and Combination Therapy

Phototherapies induced by photoactive nanomaterials have inspired and accentuated the importance of nanomedicine in cancer therapy in recent years. During these light-activated cancer therapies, a nanoagent can produce heat and cytotoxic reactive oxygen species by absorption of light energy for photothermal therapy (PTT) and photodynamic therapy (PDT). However, PTT is limited by the self-protective nature of cells, with upregulated production of heat shock proteins (HSP) under mild hyperthermia, which also influences PDT. To reduce HSP production in cancer cells and to enhance PTT/PDT, small HSP inhibitors that can competitively bind at the ATP-binding site of an HSP could be employed. Alternatively, reducing intracellular glucose concentration can also decrease ATP production from the metabolic pathways and downregulate HSP production from glucose deprivation. Other than reversing the thermal resistance of cancer cells for mild-temperature PTT, an HSP inhibitor can also be integrated into functionalized nanomaterials to alleviate tumor hypoxia and enhance the efficacy of PDT. Furthermore, the co-delivery of a small-molecule drug for direct HSP inhibition and a chemotherapeutic drug can integrate enhanced PTT/PDT with chemotherapy (CT). On the other hand, delivering a glucose-deprivation agent like glucose oxidase (GOx) can indirectly inhibit HSP and boost the efficacy of PTT/PDT while combining these therapies with cancer starvation therapy (ST). In this review, we intend to discuss different nanomaterial-based approaches that can inhibit HSP production via ATP regulation and their uses in PTT/PDT and cancer combination therapy such as CT and ST.

Insight into the potential candidate genes and signaling pathways involved in lymphoma disease in dogs using a comprehensive whole blood transcriptome analysis

Lymphoma is one of the most prevalent hematological cancers, accounting for 15-20 % of new cancer diagnoses in dogs. Therefore, this study aims to explore the important genes and pathways involved in canine lymphoma progression and understand the underlying molecular mechanisms using RNA sequencing. In this study, RNAs acquired from seven pairs of lymphoma and non-lymphoma blood samples were sequenced from different breeds of dogs. Sequencing reads were preprocessed, aligned with the reference genome, assembled and expressions were estimated through bioinformatics approaches. At a false discovery rate (FDR) < 0.05 and fold change (FC) ≥ 1.5, a total of 625 differentially expressed genes (DEGs) were identified between lymphoma and non-lymphoma samples, including 347 up-regulated DEGs such as SLC38A11, SCN3A, ZIC5 etc. and 278 down-regulated DEGs such as LOC475937, CSMD1, KRT14 etc. GO enrichment analysis showed that these DEGs were highly enriched for molecular function of ATP binding and calcium ion binding, cellular process of focal adhesion, and biological process of immune response, and defense response to virus. Similarly, KEGG pathways analysis revealed 11 significantly enriched pathways such as ECM-receptor interaction, cell cycle, PI3K-Akt signaling pathway, ABC transporters etc. In the protein-protein interaction (PPI) network, CDK1 was found to be a top hub gene with highest degree of connectivity. Three modules selected from the PPI network showed that canine lymphoma was highly associated with cell cycle, ECM-receptor interaction, hypertrophic cardiomyopathy, dilated cardiomyopathy and RIG-I-like receptor signaling pathway. Overall, our findings highlighted new candidate therapeutic targets for further testing in canine lymphoma and facilitate the understanding of molecular mechanism of lymphoma's progression in dogs.

l-Asparaginase synergizes with etoposide via the PI3K/Akt/mTOR pathway in Epstein-Barr virus-positive Burkitt lymphoma

Burkitt lymphoma (BL) is an aggressive Epstein-Barr virus (EBV)-driven B-cell lymphoma characterized by the translocation and rearrangement of the c-Myc proto-oncogene. High-intensity multidrug chemotherapy regimens have a limited effect on the survival of refractory or relapsed BL patients, mainly owing to the high EBV load and drug resistance. l-asparaginase ( l-Asp) and etoposide (VP-16) play a beneficial role in EBV-related lymphoproliferative diseases; however, their roles and mechanisms in BL remain unclear. In this study, we found that VP-16 inhibited BL cell proliferation and arrested the cell cycle at the G₂ /M phase. It also induced autophagy and activated the extrinsic and intrinsic apoptotic signaling pathways in BL cells. Mechanistically, VP-16 inhibited c-Myc expression and regulated the PI3K/Akt/mTOR signaling pathway. Notably, VP-16 also showed a specific synergistic effect with l-Asp to induce apoptosis in EBV-positive BL cells but not in EBV-negative BL cells. VP-16 combined with l-Asp further inhibited c-Myc expression and downregulated the PI3K/Akt/mTOR signaling pathway. Additionally, we found that VP-16 inhibited the expression of latent membrane protein 1 (LMP1), and in combination with l-Asp further decreased LMP1 expression in Raji cells. Our in vivo data also showed that the dual-drug combination significantly inhibited the growth of BL tumors and prolonged the survival of mice compared to VP-16 alone. In conclusion, this study provides new evidence that l-Asp may enhance the antitumor effect of VP-16 by inhibiting the PI3K/Akt/mTOR signaling pathway in EBV-positive BL cells.

Raltitrexed as a synergistic hyperthermia chemotherapy drug screened in patient-derived colorectal cancer organoids

OBJECTIVE

Organoids have recently been used as in vitro models to screen chemotherapy drugs in combination with hyperthermia treatment in colorectal cancer. Our research aimed to establish a library of patient-derived colorectal cancer organoids to evaluate synergism between chemotherapy drugs and hyperthermia; validate an index of the hyperthermia chemotherapy sensitization enhancement ratio (HCSER) to identify the chemotherapeutics most enhanced by hyperthermia; and recommend chemotherapy drugs for hyperthermic intraperitoneal treatment.

METHODS

Organoids were grown from cells extracted from colorectal cancer patient samples or colorectal cancer cell lines. Cells from both sources were encapsulated in 3D Matrigel droplets, which were formulated in microfluidics and phase-transferred into identical cell-laden Matrigel microspheres. The microspheres were seeded in 96-well plates, with each well containing a single microsphere that developed into an organoid after 7 days. The organoids were used to evaluate the efficacy of chemotherapy drugs at both 37°C as a control and 43°C for 90 min to examine hyperthermia synergism. Cell viability was counted with 10% CCK8.

RESULTS

We successfully established a library of colorectal cancer organoids from 22 patient parental tumors. We examined the hyperthermia synergism of 7 commonly used hyperthermic intraperitoneal chemotherapy drugs. In 11 of the 22 patient organoids, raltitrexed had significant hyperthermia synergism, which was indexed as the highest HCSER score within each patient group.

CONCLUSIONS

Our results primarily demonstrated the use of patient-derived colorectal cancer organoids as in vitro models to evaluate hyperthermia synergistic chemotherapeutics. We found that hyperthermia enhanced the effect of raltitrexed the most among the common anti-colorectal cancer drugs.

Inhibition of the PI3K/AKT signaling pathway sensitizes diffuse large B-cell lymphoma cells to treatment with proteasome inhibitors via suppression of BAG3

Proteasome inhibitors represent a novel class of drugs that have clinical efficacy against hematological and solid cancer types, including acute myeloid leukaemia, myelodysplastic syndrome an non-small cell lung cancer. It has been demonstrated that the anti-apoptotic protein B-cell lymphoma-2-associated athanogene 3 (BAG3) is induced by proteasome inhibitors in various cancer cells and serves an important role in chemotherapy resistance. The phosphatidylinositol 3-kinase (PI3K)/RAC-α serine/threonine-protein kinase (AKT) pathway is constitutively activated in a number of lymphoid malignancy types, including diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. In the present study, the aim was to elucidate the role of the PI3K/AKT signaling pathway in the induction of BAG3, following exposure to a proteasome inhibitor in DLBCL cell lines. Bortezomib and MG132 were used as proteasome inhibitors. Western blotting was used to evaluate the roles of proteasome inhibitors and the PI3K/AKT pathway in BAG3 induction in DLBCL cells (LY1 and LY8), and LY294002 was used to block the PI3K/AKT pathway. Cell viability was detected using a Cell Counting Kit-8 assay. Apoptosis of LY1 and LY8 cells was quantified by Annexin V/7-amino-actinomycin D flow cytometry. The BAG3 protein was markedly induced upon exposure to bortezomib and MG132 in a dose-dependent manner. The PI3K/AKT inhibitor LY294002 significantly suppressed the induction of BAG3 by proteasome inhibitors. Inhibition of the PI3K/AKT pathway decreased the proliferation and increased the apoptosis induced by proteasome inhibitors. The present results indicated that the PI3K/AKT pathway is associated with the activation of BAG3 expression in DLBCL cells, and is involved in the protective response against proteasome inhibition.

Inhibition of JAK2/STAT3 Signaling Pathway Suppresses Proliferation of Burkitt's Lymphoma Raji Cells via Cell Cycle Progression, Apoptosis, and Oxidative Stress by Modulating HSP70

Background

The aim of this study was to investigate the effect of the JAK2/STAT3 pathway on the proliferation, cell cycle distribution, apoptosis, and oxidative stress of Raji cells via regulating HSP70 expression.

Material/Methods

Raji cells were divided into Blank, HSP70 siRNA, NC siRNA, AG490 (a JAK2/STAT3 signaling pathway inhibitor), and HSP70 siRNA + rh JAK2 (recombinant human JAK2) groups. HSP70 expression was detected by quantitative real-time reverse transcription-PCR (qRT-PCR); the expression levels of HSP70 and JAK2/STAT3 pathway-related proteins were evaluated by Western blotting; cell proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays; cell cycle distribution was observed by flow cytometry; cell apoptosis was tested by Annexin V-FITC/PI and Hoechst 33342/PI staining; reactive oxygen species (ROS) production was measured by dichloro-dihydro-fluorescein diacetate (DCFH-DA) assays; and MDA content and SOD and GSH-Px activities were determined using detection kits.

Results

AG490 obviously down-regulated HSP70 expression, inhibited proliferation, induced cell cycle arrest at the G0/G1 phase, and promoted apoptosis in Raji cells; these effects were similar to the effects of HSP70 siRNA. Furthermore, ROS production and MDA content were increased in Raji cells treated with HSP70 siRNA or AG490, while SOD and GSH-Px activities were reduced. Raji cells in the HSP70 siRNA + rh JAK2 group did not significantly differ from those in the Blank group in regards to proliferation, cell cycle, apoptosis, and oxidative stress.

Conclusions

Blocking the JAK2/STAT3 signaling pathway may inhibit proliferation, induce cell cycle arrest, and promote oxidative stress and apoptosis in Raji cells via the down-regulation of HSP70.

Salidroside inhibits the proliferation and migration of gastric cancer cells via suppression of Src‑associated signaling pathway activation and heat shock protein 70 expression

Salidroside, an active ingredient extracted from the Rhodiola rosea plant, has potential anti-tumor effects. However, the effects of salidroside on gastric cancer cell proliferation and migration remain unclear. In the present study, the inhibitory effects of salidroside on gastric cancer cell proliferation, migration and invasion and the molecular mechanisms underlying these effects were investigated. The human gastric cancer cell line, BGC-823, was treated with different concentrations of salidroside (200, 400 and 600 µg/ml). Cell proliferation was determined with Cell Counting Kit-8 and colony formation assays, and the migration and invasion of cells was detected by a wound healing and Transwell assay, respectively. Western blotting was performed to detect the levels of N-cadherin, E-cadherin and heat shock protein (HSP)70. In addition, the phosphorylation of proto-oncogene tyrosine-protein kinase Src (Src), protein kinase B (Akt), mitogen activated protein kinase 1 (ERK), signal transducer and activator of transcription (STAT)3 and focal adhesion kinase 1 (FAK) was examined by western blotting. The levels of matrix metalloproteinase (MMP)-2 and MMP-9 were determined by enzyme-linked immunosorbent assay kits. Levels of reactive oxygen species (ROS) in cells were measured by a fluorescence plate reader with dichloro-dihydro-fluorescein diacetate. The results indicated that salidroside significantly suppressed cell proliferation and colony formation, inhibited cell migration and invasion, increased E-cadherin expression and decreased N-cadherin, MMP-2 and MMP-9 expression. Furthermore, salidroside suppressed ROS production and subsequently reduced the phosphorylation of Src, Akt, ERK and FAK. Salidroside also inhibited HSP70 expression, and HSP70 overexpression reversed the inhibitory effects of salidroside on BGC-823 cell proliferation, migration and invasion. In conclusion, the present study revealed that salidroside inhibited the proliferation, migration and invasion of BGC-823 cells by downregulating ROS-mediated Src-associated signaling pathway activation and HSP70 expression.

Nuclear heat shock protein 110 expression is associated with poor prognosis and hyperthermo-chemotherapy resistance in gastric cancer patients with peritoneal metastasis

AIM

To investigate the significance of heat shock protein 110 (HSP110) in gastric cancer (GC) patients with peritoneal metastasis undergoing hyperthermo-chemotherapy.

METHODS

Primary GC patients (n = 14) with peritoneal metastasis or positive peritoneal lavage cytology who underwent distal or total gastrectomy between April 2000 and December 2011 were enrolled in this study. The patients underwent postoperative intraperitoneal hyperthermo-chemotherapy using a Thermotron RF-8 heating device two weeks after surgery. We analyzed nuclear HSP110 expression in surgically resected tumors using immunohistochemistry. Additionally, the effect of HSP110 suppression on hyptherthermo-chemosensitivity was assessed in vitro in the MKN45 GC cell line using the HSP inhibitor KNK437.

RESULTS

HSP110 immnohistochemical staining in 14 GC patients showed that five (35.7%) samples belonged to the low expression group, and nine (64.3%) samples belonged to the high expression group. Progression-free survival was significantly shorter in the HSP110 high-expression group than in the low-expression group (P = 0.0313). However, no significant relationships were identified between HSP110 expression and the clinicopathological characteristics of patients. Furthermore, high HSP110 expression was not an independent prognostic factor in GC patients with peritoneal metastasis (P = 0.0625). HSP110 expression in MKN45 cells was suppressed by KNK437 at the hyperthermic temperature of 43 °C in vitro. Comparison of MKN45 cell proliferation in the presence and absence of KNK437 at 43 °C, revealed that proliferation was significantly decreased when HSP110 was inhibited by KNK437. Additionally, HSP110 suppression via HSP inhibitor treatment increased cellular sensitivity to hyperthermo-chemotherapy in vitro.

CONCLUSION

The expression of nuclear HSP110 in GC patients might be a new marker of chemosensitivity and a therapeutic target for patients who are tolerant to existing hyperthermo-chemotherapies.

A correlation analysis between tumor imaging changes and p-AKT and HSP70 expression in tumor cells after osteosarcoma chemotherapy

This study sought to investigate osteosarcoma property changes after neoadjuvant chemotherapy and to analyze any correlation between changes with phospho-AKT (p-AKT) and heat shock protein 70 (HSP70) expression in osteosarcoma cells. Thirty patients with osteosarcoma treated at Liaocheng People's Hospital between January and October, 2016 were given an imaging examination before and after neoadjuvant chemotherapy to examine osteosarcoma tumor properties, with images scored. Immunohistochemistry was used to determine p-AKT and HSP70 expression levels, as well as tumor cell necrosis rate (TCNR), in specimens obtained before and after chemotherapy. The correlation between the imaging changes of osteosarcoma after chemotherapy and the expressions of p-AKT and HSP70 in tumor cells. Compared with pre-chemotherapy, the imaging scores of the 30 patients significantly increased after chemotherapy (P<0.05). The radiographic score of the TCNR ≥90% group was 11.3±0.5, which was significantly higher than that of the TCNR <90% group (8.7±0.3, P<0.05). p-AKT expression in osteosarcoma cells was found in 13.3% of samples (4/30 cases) after chemotherapy, which was significantly lower than prior to chemotherapy (73.3%, 22/30 cases, P<0.05). After chemotherapy, HSP70 expression in osteosarcoma cells was found in 6.7% of samples (2/30 cases), which was significantly lower than prior to chemotherapy (83.3%, 25/30 cases, P<0.05). p-AKT and HSP70 expression levels were found to be correlated with TCNR after chemotherapy (P<0.05). After chemotherapy, p-AKT and HSP70 expression levels demonstrated a positive correlation with TCNR. Tumor property changes, as uncovered by imaging, were significantly inversely correlated with tumor cell p-AKT and HSP70 expression after chemotherapy. Therefore, osteosarcoma properties, as determined through X-ray imaging, were closely related to p-AKT and HSP70 expression in osteosarcoma cells after neoadjuvant chemotherapy. The effect of chemotherapy can be evaluated by observing the above examination results.

Heat shock-induced HIKESHI protects cell viability via nuclear translocation of heat shock protein 70

Heat shock proteins (HSPs), particularly HSP70, help restore normal cellular function following damage caused by stressors. HSP expression in tumor tissues indicates cancer progression, and while the development of HSP inhibitors is progressing, these substances are not widely used to treat cancer. HIKESHI (C11orf73) does not control the intracellular movement of HSP70 at normal temperatures; however, it does regulate the function and movements of HSP70 during heat shock. In this study, we examined the intracellular movement of HSP70 during heat shock to investigate the significance of HIKESHI expression in gastric cancer (GC) and determine if HIKESHI inhibition has cytotoxic effects. We examined HIKESHI using GC cell lines and immunostaining in 207 GC tissue samples. HIKESHI expression in GC tissues was associated with the progression of lymphatic invasion. Suppressing HIKESHI using siRNA did not affect cell viability at normal temperatures. However, suppressing HIKESHI during heat shock inhibited HSP70 nuclear transport and suppressed cell viability. Our results suggest that HIKESHI is a marker of cancer progression and that the combination of HIKESHI inhibition and hyperthermia is a therapeutic tool for refractory GC.

Nuclear heat shock protein 110 expression is associated with poor prognosis and chemotherapy resistance in gastric cancer

Heat shock protein (HSP) expression is induced by the exposure to stress, such as fever, oxidative stress, chemical exposure, and irradiation. In cancer, HSP promotes the survival of malignant cells by inhibiting the induction of apoptosis. In colorectal cancer, a loss-of-function mutation of HSP110 (HSP110ΔE9) has been identified. HSP110ΔE9 inhibits the nuclear translocation of wild-type HSP110, which is important for its chaperone activity and anti-apoptotic effects. The patients carrying HSP110ΔE9 mutation exhibit high sensitivity to anticancer agents, such as oxaliplatin and 5-fluorouracil. There is still insufficient information about HSP110 localization, the clinicopathological significance of HSP110 expression, and its association with chemotherapy resistance in gastric cancer. Here, we found that high nuclear expression of HSP110 in gastric cancer tissues is associated with cancer progression, poor prognosis, and recurrence after adjuvant chemotherapy. In vitro results showed that HSP110 suppression increases the sensitivity to 5-fluorouracil and cisplatin of human gastric cancer cell lines. Our results suggest that nuclear HSP110 may be a new drug sensitivity marker for gastric cancer and a potential molecular therapeutic target for the treatment of gastric cancer patients with acquired anticancer drug resistance.

Determining protein biomarkers for DLBCL using FFPE tissues from HIV negative and HIV positive patients

DLBCL is the most common lymphoma subtype occurring in older populations as well as in younger HIV infected patients. The current treatment options for DLBCL are effective for most patients yet the relapse rate is high. While many biomarkers for DLBCL exist, they are not in clinical use due to low sensitivity and specificity. In addition, these biomarkers have not been studied in the HIV context. Therefore, the identification of new biomarkers for HIV negative and HIV positive DLBCL, may lead to a better understanding of the disease pathology and better therapeutic design. Protein biomarkers for DLBCL were determined using MALDI imaging mass spectrometry (IMS) and characterised using LC-MS. The expression of one of the biomarkers, heat shock protein (Hsp) 70, was confirmed on a separate cohort of samples using immunohistochemistry. The biomarkers identified in the study consisted of four protein clusters including glycolytic enzymes, ribosomal proteins, histones and collagen. These proteins could differentiate between control and tumour tissue, and the DLBCL immunohistochemical subtypes in both cohorts. The majority (41/52) of samples in the confirmation cohort were negative for Hsp70 expression. The HIV positive DLBCL cases had a higher percentage of cases expressing Hsp70 than their HIV negative counterparts. The non-GC subtype also frequently overexpressed Hsp70, confirming MALDI IMS data. The expression of Hsp70 did not correlate with survival in both the HIV negative and HIV positive cohort. This study identified potential biomarkers for HIV negative and HIV positive DLBCL from FFPE tissue sections. These may be used as diagnostic and prognostic markers complementary to current clinical management programmes for DLBCL.

MicroRNA-520a attenuates proliferation of Raji cells through inhibition of AKT1/NF-κB and PERK/eIF2α signaling pathway

Burkitt's lymphoma (BL) is a fast growing cancer of the human lymphatic system, and an extremely invasive B-cell non-Hodgkin's lymphoma. We explored the mechanism of apoptosis in Raji cells associated with the post-transcriptional regulation factors. To confirm that the predicted microRNA-520a (miR-520a) is matched with AKT1, 3' untranslated region (UTR) luciferase activity of AKT1 was used in the assessment. In the presence of the mimics or inhibitors of miR-520a, cell function of Raji, such as proliferation, growth and apoptosis were analyzed. The expression of endoplasmic reticulum (ER) stress‑related proteins were examined. Luciferase reporter analysis showed that miR‑520a leads to decreased activity of luciferase gene fused with AKT1 3'UTR. Therefore, AKT1 is a direct target of miR‑520a. Our data indicated that the mimics of miR‑520a inhibited growth, proliferation of Raji cells and promoted its apoptosis, which was related to downregulation of AKT1, NF‑κB and ER stress response mediated by PERK/eIF2α pathway. On the contrary, the inhibitors of miR‑520a promoted growth, proliferation of Raji cells and inhibited its apoptosis, which was related to AKT1/NF‑κB and PERK/eIF2α pathway. We identified miR‑520a, which specifically binds to AKT1 mRNA 3'UTR. miR‑520a is a crucial mediator for proliferation and ER stress in Raji cells through regulating the AKT1/NF‑κB or PERK/eIF2α signaling pathway. Our findings suggest that targeting miR‑520a is a promising therapeutic strategy in BL.

Fisetin targets phosphatidylinositol-3-kinase and induces apoptosis of human B lymphoma Raji cells

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Fisetin inhibits PI3K activity at the enzymatic and cellular levels.

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Fisetin induces the apoptosis of Raji cells by downregulating cIAP-2 protein expression.

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The pro-apoptotic activity of fisetin may be linked to a potential to inhibit mTOR signaling and to induce DNA damage.

Aberrant regulation of phosphatidylinositol-3-kinases (PI3Ks) is known to be involved in the progression of cancers. PI3K-binding flavonoids such as quercetin and myricetin have been shown to inhibit PI3K activity, but the direct targeting of fisetin to PI3K has not been established. Here, we carried out an in silico investigation of fisetin binding to PI3K and determined fisetin’s inhibitory activity in enzymatic and cell-based assays. In addition, fisetin induced apoptosis in human Burkitt’s lymphoma Raji cells by inhibiting both PI3Ks and mammalian target of rapamycin (mTOR). Our results indicate that fisetin may serve as a natural backbone for the development of novel dual inhibitors of PI3Ks and mTOR for the treatment of cancer.

Efficacy, safety, pharmacokinetics and pharmacodynamics of SAR245409 (voxtalisib, XL765), an orally administered phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor: a phase 1 expansion cohort in patients with relapsed or refractory lymphoma

The maximum tolerated dose of SAR245409 (voxtalisib), a pan-class I phosphoinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor, was determined in a phase 1 dose-escalation study in advanced solid tumors. We report safety, pharmacokinetics (PK), pharmacodynamics and preliminary efficacy of SAR245409 capsules 50 mg twice daily in an expansion cohort of 16 patients with relapsed/refractory lymphoma. The most common treatment-related adverse events (AEs) were nausea (31.3%) and diarrhea (25.0%). The most common grade 3/4 treatment-related AE was increased alanine aminotransferase (12.5%). PK results were consistent with solid tumors, confirming a relatively short steady-state half-life (mean 4.61 h). Among 12 evaluable patients, one complete response and two partial responses were achieved in patients with and without PI3K/mTOR pathway alterations. In a patient with mantle cell lymphoma achieving PR, SAR245409 was associated with significant inhibition of PI3K/mTOR and extracellular signal-related kinase (ERK) pathways. Preliminary efficacy warrants further evaluation of SAR245409 in lymphoma.

Nitric oxide plays a dual role in the oxidative injury of cultured rat microglia but not astroglia

Nitric oxide (NO) and oxidative stress caused by reactive oxygen species (ROS) accumulation are two important factors that lead to the progression of human neurological diseases. NO can be detrimental or protective to neurons under oxidative toxicity; however, in the case of brain exposure to oxidative stress, in addition to neurons, the existence of glia may also be disturbed by toxic ROS. The influence NO will have on ROS-mediated glial injury remains unclear. Here, we examined the effects of NO on cell viability under oxidative stress induced by hydrogen peroxide (H2O2) in rat primary mixed glia cultures, as well as pure astroglia and microglia cultures. We found that in mixed glia cultures, both H2O2 and NO donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP) elicited cell death in a concentration-dependent manner. Combinations of H2O2 and SNAP at sublytic concentrations were sufficient to damage mixed glia, and sublytic concentrations of SNAP could reduce the insults that resulted from toxic H2O2. Furthermore, in microglia or astroglia, sublytic concentrations of H2O2 were toxic when combined with SNAP, and the potency was increased with an increased SNAP concentration. In microglia but not astroglia, a toxic H2O2-induced apoptotic injury was attenuated by a sublytic level of SNAP. H2O2 at toxic levels activated p38 mitogen-activated protein kinases (MAPK) and p53 pathways and increased DNA double strand breaks (DSBs) in microglia, whereas the rescue exerted by sublytic SNAP against toxic H2O2 occurred via the activation of both Akt and extracellular-signal-regulated kinase (ERK) cascades and decreased DNA DSBs. Moreover, a sublytic concentration of SNAP induced both heat shock protein 70 and heme oxygenase-1, which may be involved in decreasing the susceptibility of microglia to H2O2 toxicity. These results suggest that NO exhibits a concentration-dependent dual action of weakening or enhancing oxidative injury in mixed glia, particularly microglia.

Clinical development of phosphatidylinositol 3-kinase inhibitors for non-Hodgkin lymphoma

Phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway is extensively explored in cancers. It functions as an important regulator of cell growth, survival and metabolism. Activation of this pathway also predicts poor prognosis in numerous human malignancies. Drugs targeting this signaling pathway have been developed and have shown preliminary clinical activity. Accumulating evidence has highlighted the important role of PI3K in non-Hodgkin lymphoma (NHL), especially in the disease initiation and progression. Therapeutic functions of PI3K inhibitors in NHL have been demonstrated both in vivo and in vitro. This review will summarize recent advances in the activation of PI3K signaling in different types of NHL and the applications of PI3K inhibitors in NHL treatment.