Phosphorylated AKT Protein Is Overexpressed in Human Peripheral T-cell Lymphomas and Predicts Decreased Patient Survival

Research progress on the mechanism of common inflammatory pathways in the pathogenesis and development of lymphoma

In recent years, the incidence and mortality rates of lymphoma have gradually increased worldwide. Tumorigenesis and drug resistance are closely related to intracellular inflammatory pathways in lymphoma. Therefore, understanding the biological role of inflammatory pathways and their abnormal activation in relation to the development of lymphoma and their selective modulation may open new avenues for targeted therapy of lymphoma. The biological functions of inflammatory pathways are extensive, and they are central hubs for regulating inflammatory responses, immune responses, and the tumour immune microenvironment. However, limited studies have investigated the role of inflammatory pathways in lymphoma development. This review summarizes the relationship between abnormal activation of common inflammatory pathways and lymphoma development to identify precise and efficient targeted therapeutic options for patients with advanced, drug-resistant lymphoma.

Genomic and transcriptomic profiling of peripheral T cell lymphoma reveals distinct molecular and microenvironment subtypes

Peripheral T cell lymphoma (PTCL) is a heterogeneous group of non-Hodgkin's lymphomas varying in clinical, phenotypic, and genetic features. The molecular pathogenesis and the role of the tumor microenvironment in PTCL are poorly understood, with limited biomarkers available for genetic subtyping and targeted therapies. Through an integrated genomic and transcriptomic study of 221 PTCL patients, we delineate the genetic landscape of PTCL, enabling molecular and microenvironment classification. According to the mutational status of RHOA, TET2, histone-modifying, and immune-related genes, PTCL is divided into 4 molecular subtypes with discrete patterns of gene expression, biological aberrations, and vulnerabilities to targeted agents. We also perform an unsupervised clustering on the microenvironment transcriptional signatures and categorize PTCL into 4 lymphoma microenvironment subtypes based on characteristic activation of oncogenic pathways and composition of immune communities. Our findings highlight the potential clinical rationale of future precision medicine strategies that target both molecular and microenvironment alterations in PTCL.

Peripheral T cell lymphomas: from the bench to the clinic

Peripheral T cell lymphomas (PTCLs) are a heterogeneous group of orphan neoplasms. Despite the introduction of anthracycline-based chemotherapy protocols, with or without autologous haematopoietic transplantation and a plethora of new agents, the progression-free survival of patients with PTCLs needs to be improved. The rarity of these neoplasms, the limited knowledge of their driving defects and the lack of experimental models have impaired clinical successes. This scenario is now rapidly changing with the discovery of a spectrum of genomic defects that hijack essential signalling pathways and foster T cell transformation. This knowledge has led to new genomic-based stratifications, which are being used to establish objective diagnostic criteria, more effective risk assessment and target-based interventions. The integration of genomic and functional data has provided the basis for targeted therapies and immunological approaches that underlie individual tumour vulnerabilities. Fortunately, novel therapeutic strategies can now be rapidly tested in preclinical models and effectively translated to the clinic by means of well-designed clinical trials. We believe that by combining new targeted agents with immune regulators and chimeric antigen receptor-expressing natural killer and T cells, the overall survival of patients with PTCLs will dramatically increase.

Dihydroartemisinin triggers c-Myc proteolysis and inhibits protein kinase B/glycogen synthase kinase 3β pathway in T-cell lymphoma cells

Recent studies have revealed a positive therapeutic effect of dihydroartemisinin (DHA) on tumor cells. However, the underlying mechanism of this has not yet been elucidated. The present study examined the potential therapeutic role and mechanism of DHA in T-cell lymphoma cells. It was revealed that DHA inhibited the proliferation of Jurkat and HuT-78 T-cell lymphoma cells in a concentration- and time-dependent manner. Furthermore, DHA reduced c-Myc protein expression at the transcriptional level, and induced the phosphorylation of c-Myc and the degradation of c-Myc oncoprotein levels. DHA treatment resulted in decreased phosphorylation of protein kinase B (Akt) and glycogen synthase 3β (GSK3β) in T-cell lymphoma cells. In addition, DHA treatment induced cell apoptosis, which was accompanied by an increased ratio of Bax/Bcl-2. Taken together, the results of the present study suggested that DHA may exert its antitumor role by accelerating c-Myc proteolysis and inhibiting the Akt/GSK3β pathway in T-cell lymphoma cells.

Transformation of mouse T cells requires MYC and AKT activity in conjunction with inhibition of intrinsic apoptosis

Peripheral T-cell lymphoma is an aggressive non-Hodgkin's lymphoma characterized by excessive proliferation of transformed mature T cells. The number and nature of genetic aberrations required and sufficient for transformation of normal T cells into lymphomas is unknown. Here, using a combinatorial in vitro-approach, we demonstrate that overexpression of MYC together with activated AKT in conditions of inhibition of intrinsic apoptosis rapidly resulted in transformation of mature mouse T cells with a frequency approaching 100%. Injection of transformed cells into mice resulted in rapid development of aggressive T cell lymphoma, characterized by spread to several organs, destruction of tissue architecture and rapid death of the animals. TcR-sequencing revealed a polyclonal repertoire of tumor cells indicating that co-expression of MYC, activated AKT and BCLXL is sufficient for tumor transformation and do not require acquisition of additional genetic events. When analyzing cells with inducible expression we found that proliferation of transformed T cells required sustained expression of both MYC and AKT. AKT exerted a dual function as it inhibited induction of, and promoted exit from, cellular quiescence and contributed to inhibion of apoptosis. Downregulation of AKT and/or MYC together with BCLXL resulted in rapid and complete elimination of cells through induction of apoptotic cell death.

A nomogram based on phosphorylated AKT1 for predicting locoregional recurrence in patients with oesophageal squamous cell carcinoma

Background: The AKT signalling pathway controls survival and growth in many malignant tumours. However, the prognostic value of phosphorylated AKT1 (p-AKT1) for locoregional-progression free survival (LPFS) in oesophageal squamous cell carcinoma (ESCC) has not been established. Our aim was to develop a nomogram to predict local recurrence using p-AKT1 and main clinical characteristics in patients with thoracic ESCC undergoing radical three-field lymph node dissection.

Methods: Immunohistochemistry was performed to examine p-AKT1 expression in 181 thoracic ESCC patients. The Kaplan-Meier method was used to calculate LPFS. Cox regression analysis was also performed to evaluate prognostic factors. A nomogram comprising biological and clinical factors was established to predict LPFS.

Results: The 5-year LPFS rate was 63.9%. Multivariate analysis revealed that expression of p-AKT1 (p<0.001), pathologic N category (p=0.004) and number of lymph nodes retrieved (p=0.001) were independent prognostic factors for LPFS. Increased expression of p-AKT1 was associated with decreased LPFS in patients with ESCC. In addition, a nomogram was established based on all significant independent factors for locoregional recurrence risk. Harrell's c-index for predicting LPFS was 0.78.

Conclusion: Activation of AKT1 was associated with poor locoregional control in ESCC patients. The nomogram, based on p-AKT1 expression and clinically significant parameters, could be used as an accurate stratification model for predicting locoregional recurrence in patients with ESCC after radical resection.

m-TOR inhibitors and their potential role in haematological malignancies

It is widely demonstrated that the PI3K-AKT-mTOR signalling is critical in normal myeloid and lymphoid development and function. Thus, it is not strange that this pathway is often deregulated in haematological tumours, providing a strong preclinical rationale for the use of drugs targeting the PI3K-AKT-mTOR axis in haematological malignancies. The main focus of this review is to examine the mammalian target of rapamycin (mTOR, also termed mechanistic target of rapamycin [MTOR]) signalling pathways and to provide a brief overview of rapalogs and second-generation mTOR inhibitors used to target its aberrant activation in cancer treatment. We will also discuss the results obtained with the use of these agents in patients with acute leukaemia, Hodgkin lymphoma, non-Hodgkin lymphomas, multiple myeloma and Waldenström macroglobulinaemia. Ongoing clinical trials in haematological malignancies that are investigating first- and second-generation mTOR inhibitors as single agents and as components of combination regimens are also presented.

Oncogenic Signaling Pathways and Pathway-Based Therapeutic Biomarkers in Lymphoid Malignancies

Lymphoma is characterized by heterogeneous biology, pathologic features, and clinical outcome. This has been proven by accumulating pathologic and molecular evidence attributed to underlying aberrant alterations at genetic, epigenetic, transcriptional, protein, microenvironmental levels, and dysregulated oncogenic signaling pathways. In the era of precision medicine, targeting oncogenic pathways to design drugs and to optimize treatment regimens for the lymphoma patients is feasible and clinically significant. As such, further understanding of the biology and the mechanisms behind lymphoma development and identification of oncogenic pathway activation and pathway-based biomarkers to better design precise therapies are challenging but hopeful. Furthermore, pathway-based targeted therapies in combination with traditional chemotherapy, single specific targeted antibody therapy, and immunotherapy might raise the hope for the patients with lymphoma, especially for relapsed and refractory lymphoma patients.

Status of PI3K/Akt/mTOR pathway inhibitors in lymphoma

The phosphatidylinositol-3-kinase (PI3K) pathway is well known to regulate a wide variety of essential cellular functions, including glucose metabolism, translational regulation of protein synthesis, cell proliferation, apoptosis, and survival. Aberrations in the PI3K pathway are among the most frequently observed in cancer, and include amplifications, rearrangements, mutations, and loss of regulators. As a net result of these anomalies, the PI3K pathway is activated in many malignancies, including in Hodgkin and non-Hodgkin lymphomas, and yields a competitive growth and survival advantage, increased metastatic ability, and resistance to conventional therapy. Numerous inhibitors targeting various nodes in the PI3K pathway are undergoing clinical development, and their current status in lymphoma will be the focus of this review.

13-methyltetradecanoic acid exhibits anti-tumor activity on T-cell lymphomas in vitro and in vivo by down-regulating p-AKT and activating caspase-3

13-Methyltetradecanoic acid (13-MTD), a saturated branched-chain fatty acid purified from soy fermentation products, induces apoptosis in human cancer cells. We investigated the inhibitory effects and mechanism of action of 13-MTD on T-cell non-Hodgkin’s lymphoma (T-NHL) cell lines both in vitro and in vivo. Growth inhibition in response to 13-MTD was evaluated by the cell counting kit-8 (CCK-8) assay in three T-NHL cell lines (Jurkat, Hut78, EL4 cells). Flow cytometry analyses were used to monitor the cell cycle and apoptosis. Proteins involved in 13-MTD-induced apoptosis were examined in Jurkat cells by western blotting. We found that 13-MTD inhibited proliferation and induced the apoptosis of T-NHL cell lines. 13-MTD treatment also induced a concentration-dependent arrest of Jurkat cells in the G₁-phase. During 13-MTD-induced apoptosis in Jurkat cells, the cleavage of caspase-3 and poly ADP-ribose polymerase (PARP, a caspase enzymolysis product) were detected after incubation for 2 h, and increased after extending the incubation time. However, there was no change in the expression of Bcl-2 or c-myc proteins. The appearance of apoptotic Jurkat cells was accompanied by the inhibition of AKT and nuclear factor-kappa B (NF-κB) phosphorylation. In addition, 13-MTD could also effectively inhibit the growth of T-NHL tumors in vivo in a xenograft model. The tumor inhibition rate in the experimental group was 40%. These data indicate that 13-MTD inhibits proliferation and induces apoptosis through the down-regulation of AKT phosphorylation followed by caspase activation, which may provide a new approach for treating T-cell lymphomas.

Simultaneous inhibition of pan-phosphatidylinositol-3-kinases and MEK as a potential therapeutic strategy in peripheral T-cell lymphomas

Peripheral T-cell lymphomas are very aggressive hematologic malignancies for which there is no targeted therapy. New, rational approaches are necessary to improve the very poor outcome in these patients. Phosphatidylinositol-3-kinase is one of the most important pathways in cell survival and proliferation. We hypothesized that phosphatidylinositol-3-kinase inhibitors could be rationally selected drugs for treating peripheral T-cell lymphomas. Several phosphatidylinositol-3-kinase isoforms were inhibited genetically (using small interfering RNA) and pharmacologically (with CAL-101 and GDC-0941 compounds) in a panel of six peripheral and cutaneous T-cell lymphoma cell lines. Cell viability was measured by intracellular ATP content; apoptosis and cell cycle changes were checked by flow cytometry. Pharmacodynamic biomarkers were assessed by western blot. The PIK3CD gene, which encodes the δ isoform of phosphatidylinositol-3-kinase, was overexpressed in cell lines and primary samples, and correlated with survival pathways. However, neither genetic nor specific pharmacological inhibition of phosphatidylinositol-3-kinase δ affected cell survival. In contrast, the pan-phosphatidylinositol-3-kinase inhibitor GDC-0941 arrested all T-cell lymphoma cell lines in the G1 phase and induced apoptosis in a subset of them. We identified phospho-GSK3β and phospho-p70S6K as potential biomarkers of phosphatidylinositol-3-kinase inhibitors. Interestingly, an increase in ERK phosphorylation was observed in some GDC -0941-treated T-cell lymphoma cell lines, suggesting the presence of a combination of phosphatidylinositol-3-kinase and MEK inhibitors. A highly synergistic effect was found between the two inhibitors, with the combination enhancing cell cycle arrest at G0/G1 in all T-cell lymphoma cell lines, and reducing cell viability in primary tumor T cells ex vivo. These results suggest that the combined treatment of pan-phosphatidylinositol-3-kinase + MEK inhibitors could be more effective than single phosphatidylinositol-3-kinase inhibitor treatment, and therefore, that this combination could be of therapeutic value for treating peripheral and cutaneous T-cell lymphomas.