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Long-term adaptation of lymphoma cell lines to hypoxia is mediated by diverse molecular mechanisms that are targetable with specific inhibitors
A large body of evidence suggests that hypoxia drives aggressive molecular features of malignant cells irrespective of cancer type. Non-Hodgkin lymphomas (NHL) are the most common hematologic malignancies characterized by frequent involvement of diverse hypoxic microenvironments. We studied the impact of long-term deep hypoxia (1% O2) on the biology of lymphoma cells. Only 2 out of 6 tested cell lines (Ramos, and HBL2) survived ≥ 4 weeks under hypoxia. The hypoxia-adapted (HA)b Ramos and HBL2 cells had a decreased proliferation rate accompanied by significant suppression of both oxidative phosphorylation and glycolytic pathways. Transcriptome and proteome analyses revealed marked downregulation of genes and proteins of the mitochondrial respiration complexes I and IV, and mitochondrial ribosomal proteins. Despite the observed suppression of glycolysis, the proteome analysis of both HA cell lines showed upregulation of several proteins involved in the regulation of glucose utilization including the active catalytic component of prolyl-4-hydroxylase P4HA1, an important druggable oncogene. HA cell lines demonstrated increased transcription of key regulators of auto-/mitophagy, e.g., neuritin, BCL2 interacting protein 3 (BNIP3), BNIP3-like protein, and BNIP3 pseudogene. Adaptation to hypoxia was further associated with deregulation of apoptosis, namely upregulation of BCL2L1/BCL-XL, overexpression of BCL2L11/BIM, increased binding of BIM to BCL-XL, and significantly increased sensitivity of both HA cell lines to A1155463, a BCL-XL inhibitor. Finally, in both HA cell lines AKT kinase was hyperphosphorylated and the cells showed increased sensitivity to copanlisib, a pan-PI3K inhibitor. In conclusion, our data report on several shared mechanisms of lymphoma cell adaptation to long-term hypoxia including: 1. Upregulation of proteins responsible for glucose utilization, 2. Degradation of mitochondrial proteins for potential mitochondrial recycling (by mitophagy), and 3. Increased dependence on BCL-XL and PI3K-AKT signaling for survival. In translation, inhibition of glycolysis, BCL-XL, or PI3K-AKT cascade may result in targeted elimination of HA lymphoma cells.
Daratumumab/lenalidomide/dexamethasone in transplant-ineligible newly diagnosed myeloma: MAIA long-term outcomes
In the MAIA study, daratumumab plus lenalidomide and dexamethasone (D-Rd) improved progression-free survival (PFS) and overall survival (OS) versus lenalidomide and dexamethasone (Rd) alone in transplant-ineligible patients with newly diagnosed multiple myeloma (NDMM). We report updated efficacy and safety from MAIA (median follow-up, 64.5 months), including a subgroup analysis by patient age (<70, ≥70 to <75, ≥75, and ≥80 years). Overall, 737 transplant-ineligible patients with NDMM were randomized 1:1 to D-Rd or Rd. The primary endpoint, PFS, was improved with D-Rd versus Rd (median, 61.9 vs 34.4 months; hazard ratio [HR], 0.55; 95% confidence interval [CI], 0.45–0.67; P < 0.0001). Median OS was not reached in the D-Rd group versus 65.5 months in the Rd group (HR, 0.66; 95% CI, 0.53–0.83; P = 0.0003); estimated 60-month OS rates were 66.6% and 53.6%, respectively. D-Rd achieved higher rates of complete response or better (≥CR; 51.1% vs 30.1%), minimal residual disease (MRD) negativity (32.1% vs 11.1%), and sustained MRD negativity (≥18 months: 16.8% vs 3.3%) versus Rd (all P < 0.0001). D-Rd demonstrated clinically meaningful efficacy benefits across age groups. No new safety concerns were observed. Updated results (median follow-up, >5 years) continue to support frontline use of D-Rd in transplant-ineligible patients with NDMM.
STAT6 mutations compensate for CREBBP mutations and hyperactivate IL4/STAT6/RRAGD/mTOR signaling in follicular lymphoma
Activating mutations in STAT6 are common in Follicular Lymphoma (FL) and transformed FL and various other B cell lymphomas. Here, we report RNA-seq based gene expression data on normal human lymph node derived B lymphocytes (NBC; N = 6), and primary human FL WT (N = 11) or mutant (N = 4) for STAT6 before and after ex vivo stimulation with IL4. We found that STAT6 mutants result in broad based augmentation of IL4-induced gene expression. Unexpectedly, in FL with WT STAT6 we measured reduced baseline and IL4-induced gene expression levels when compared with NBC lymphocytes or FL with STAT6 mutations. We tracked the attenuated IL4/JAK/STAT6 response to co-existing CREBBP mutations and experimentally verified that intact CREBBP is required for the induction of many IL4-induced genes. One of the IL4-induced genes here identified is RRAGD, a small G-protein involved in lysosomal mTOR activation. We show that IL4 treatment induced RRAGD expression, that RRAGD is required for mTOR activation in lymphoma cells and that IL4-enhanced BCR signaling induced mTOR activation. The IL4 and BCR-induced mTOR activation was reduced by CREBBP mutants and augmented by mutant STAT6, establishing a link between STAT6 mutations and mTOR regulated pro-growth pathways in lymphoma.
Targeting of TAMs: can we be more clever than cancer cells?
With increasing incidence and geography, cancer is one of the leading causes of death, reduced quality of life and disability worldwide. Principal progress in the development of new anticancer therapies, in improving the efficiency of immunotherapeutic tools, and in the personification of conventional therapies needs to consider cancer-specific and patient-specific programming of innate immunity. Intratumoral TAMs and their precursors, resident macrophages and monocytes, are principal regulators of tumor progression and therapy resistance. Our review summarizes the accumulated evidence for the subpopulations of TAMs and their increasing number of biomarkers, indicating their predictive value for the clinical parameters of carcinogenesis and therapy resistance, with a focus on solid cancers of non-infectious etiology. We present the state-of-the-art knowledge about the tumor-supporting functions of TAMs at all stages of tumor progression and highlight biomarkers, recently identified by single-cell and spatial analytical methods, that discriminate between tumor-promoting and tumor-inhibiting TAMs, where both subtypes express a combination of prototype M1 and M2 genes. Our review focuses on novel mechanisms involved in the crosstalk among epigenetic, signaling, transcriptional and metabolic pathways in TAMs. Particular attention has been given to the recently identified link between cancer cell metabolism and the epigenetic programming of TAMs by histone lactylation, which can be responsible for the unlimited protumoral programming of TAMs. Finally, we explain how TAMs interfere with currently used anticancer therapeutics and summarize the most advanced data from clinical trials, which we divide into four categories: inhibition of TAM survival and differentiation, inhibition of monocyte/TAM recruitment into tumors, functional reprogramming of TAMs, and genetic enhancement of macrophages.
Improved prognosis of advanced-stage extranodal NK/T-cell lymphoma: results of the NKEA-Next study
A retrospective study of extranodal natural killer/T-cell lymphoma (ENKL) patients diagnosed between 2014 and 2021 in Japan was conducted. Among 351 patients with sufficient data, 116 (33%) were in the advanced stage (5 in stage III and 111 in stage IV) at diagnosis, and were further analyzed. The median age was 60 years (range: 19–90), and 68 (59%) were male. Ninety-four (85%) of stage IV patients had two or more extranodal involvements. The most common first-line regimen was SMILE (steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide; 52%). The 2-year overall survival (OS) for all patients was 38.5%, which was significantly improved after 2017 (25.2% for 2014–2017 vs. 50.7% for 2018–2021; P = 0.008). Patients treated with SMILE showed better OS than those treated with DeVIC or CHOP (2y-OS: 57.1%, 35.8%, and 0%, respectively; P < 0.001). The prognosis was significantly better in patients who received hematopoietic stem cell transplantation (HSCT) than in those who did not (2-year OS: 68.3% vs. 17.6%, P < 0.001). Multivariate analysis showed SMILE and HSCT were significant factors for OS. In conclusion, the prognosis of advanced-stage ENKL has improved in recent years. The L-asparaginase-containing chemotherapy and subsequent HSCT is considered the recommended strategy.
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