5-AZA Upregulates SOCS3 and PTPN6/SHP1, Inhibiting STAT3 and Potentiating the Effects of AG490 against Primary Effusion Lymphoma Cells.

Epigenetic modifications, including aberrant DNA methylation occurring at the promoters of oncogenes and oncosuppressor genes and histone modifications, can contribute to carcinogenesis. Aberrant methylation mediated by histone methylatransferases, alongside histones, can affect methylation of proteins involved in the regulation of pro-survival pathways such as JAK/STAT and contribute to their activation. In this study, we used DNA or histone demethylating agents, 5-Azacytidine (5-AZA) or DS-3201 (valemetostat), respectively, to treat primary effusion lymphoma (PEL) cells, alone or in combination with AG490, a Signal transducer and activator of transcription 3 (STAT3) inhibitor. Cell viability was investigated by trypan blue assay and FACS analysis. The molecular changes induced by 5-AZA and/or AG490 treatments were investigated by Western blot analysis, while cytokine release by PEL cells treated by these drugs was evaluated by Luminex. Statistical analyses were performed with Graphpad Prism® software (version 9) and analyzed by Student's t test or a nonparametric one-way ANOVA test. The results obtained in this study suggest that 5-AZA upregulated molecules that inhibit STAT3 tyrosine phosphorylation, namely Suppressor of Cytokine Signaling 3 (SOCS3) and tyrosine-protein phosphatase non-receptor type (PTPN) 6/Src homology region 2 domain-containing phosphatase-1 (SHP-1), reducing STAT3 activation and downregulating several STAT3 pro-survival targets in PEL cells. As this lymphoma is highly dependent on the constitutive activation of STAT3, 5-AZA impaired PEL cell survival, and when used in combination with AG490 JAK2/STAT3 inhibitor, it potentiated its cytotoxic effect. Differently from 5-AZA, the inhibition of the EZH1/2 histone methyltransferase by DS-3201, reported to contribute to STAT3 activation in other cancers, slightly affected STAT3 phosphorylation or survival in PEL cells, either alone or in combination with AG490. This study suggests that 5-AZA, by upregulating the expression level of SOCS3 and PTPN6/SHP1, reduced STAT3 activation and improved the outcome of treatment targeting this transcription factor in PEL cells.

Clinical, Functional, and Nutritional Efficacy of a Glutamine-Enriched Oligomeric Diet in Patients with Rectal Cancer.

AIMS: This work aims to evaluate the efficacy of nutritional supplementation with a glutamine-enriched oligomeric diet (GEOD) compared to a standard polymeric diet (SPD) in terms of oncology treatment-related diarrhea (OTRD) (frequency and consistency of stools), gastrointestinal toxicity, and functional and nutritional progress. METHODS: This prospective cohort study compared two groups of patients with rectal cancer in treatment with neoadjuvant chemotherapy and radiotherapy who were at risk of malnutrition. Patients were randomized to receive either 400 ml of GEOD or of SPD from the start of radiotherapy to 30 days after its completion. RESULTS: Eighty patients were recruited, 40 per arm. The GEOD arm had improved stool consistency and a greater reduction in the number of stools compared to the SPD arm (p < 0.001). The relative risk (RR) of developing diarrhea in the GEOD arm was 0.059 (95% CI 0.015-0.229). There was a reduced risk of developing intestinal mucositis in the GEOD arm compared to the SPD arm [RR 0.202 (95% CI 0.102 - 0.399)]. The GEOD arm had greater improvements in functional and nutritional status (p < 0.001). CONCLUSIONS: GEOD had a protective effect in terms of the development of gastrointestinal toxicity associated with chemotherapy and radiotherapy treatment in patients with rectal cancer.

HSPs/STAT3 Interplay Sustains DDR and Promotes Cytokine Release by Primary Effusion Lymphoma Cells.

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma, against which current therapies usually fail. In the present study, we show that targeting HSPs, such as HSP27, HSP70 and HSP90, could be an efficient strategy to reduce PEL cell survival, as it induces strong DNA damage, which correlated with an impairment of DDR. Moreover, as HSP27, HSP70 and HSP90 cross talk with STAT3, their inhibition results in STAT3 de-phosphorylation and. On the other hand, the inhibition of STAT3 may downregulate these HSPs. These findings suggest that targeting HSPs has important implications in cancer therapy, as it can reduce the release of cytokines by PEL cells, which, besides affecting their own survival, could negatively influence anti-cancer immune response.

NFE2L2 and STAT3 Converge on Common Targets to Promote Survival of Primary Lymphoma Cells.

NFE2L2 and STAT3 are key pro-survival molecules, and thus, their targeting may represent a promising anti-cancer strategy. In this study, we found that a positive feedback loop occurred between them and provided evidence that their concomitant inhibition efficiently impaired the survival of PEL cells, a rare, aggressive B cell lymphoma associated with the gammaherpesvirus KSHV and often also EBV. At the molecular level, we found that NFE2L2 and STAT3 converged in the regulation of several pro-survival molecules and in the activation of processes essential for the adaption of lymphoma cells to stress. Among those, STAT3 and NFE2L2 promoted the activation of pathways such as MAPK3/1 and MTOR that positively regulate protein synthesis, sustained the antioxidant response, expression of molecules such as MYC, BIRC5, CCND1, and HSP, and allowed DDR execution. The findings of this study suggest that the concomitant inhibition of NFE2L2 and STAT3 may be considered a therapeutic option for the treatment of this lymphoma that poorly responds to chemotherapies.

p62/SQSTM1 promotes mitophagy and activates the NRF2-mediated antioxidant and anti-inflammatory response restraining EBV-driven B lymphocyte proliferation.

Reactive oxygen species (ROS) and DNA repair, respectively, promote and limit oncogenic transformation of B cells driven by Epstein-Barr virus (EBV). We have previously shown that EBV infection reduced autophagy in primary B lymphocytes and enhanced ROS and interleukin 6 (IL-6) release, promoting B-cell proliferation and immortalization. In this study, we explored the role of p62/SQSTM1, accumulated as a consequence of autophagy reduction in EBV-infected B lymphocytes, and found that it exerted a growth-suppressive effect in these cells. At the molecular level, we found that p62 counteracted IL-6 production and ROS increase by interacting with NRF2 and promoting mitophagy. Moreover, p62/NRF2 axis sustained the expression level of H2AX and ataxia-telangiectasia mutated (ATM), whose activation has been shown to have growth-suppressive effects during the first steps of EBV infection, before latency is established. In conclusion, this study shows for the first time that the accumulation of p62 and the activation of p62/axis counteracted EBV-driven proliferation of primary B lymphocytes.

The impairment of DDR reduces XBP1s, further increasing DNA damage, and triggers autophagy via PERK/eIF2alpha in MM and IRE1alpha/JNK1/2 in PEL cells.

Cancer cells, particularly MM, that are highly secretory cells, and PEL cells that harbor KSHV, are characterized by high level of stress to which they adapt by activating DDR, UPR and autophagy. It is known that UPR sensors may affect DDR, but whether DDR manipulation influences UPR is less known. In this study, we found an intricate interplay between these responses. Indeed, PARP and CHK1 inhibition by AZD2461 and UCN-01, by downregulating c-Myc, reduced the expression of XBP1s, constitutively expressed in these cells, and upregulated CHOP. Interestingly, given the role of XBP1s in regulating DDR, BRCA-1 expression level was reduced, exacerbating DNA damage. Finally, DDR/UPR interplay activated a pro-survival autophagy via PERK/eIF2alpha axis in MM and IRE1alpha/JNK axis in PEL cells, since in the latter case PERK/eIF2alpha activation could be prevented by KSHV that, as other herpesviruses, tries to avoid the blocks of protein translation that this pathway may induce.

Anticancer effect of AZD2461 PARP inhibitor against colon cancer cells carrying wt or dysfunctional p53.

Colon cancer is one of the most common cancers, currently treated with traditional chemotherapies or alternative therapies. However, these treatments are still not enough effective and induce several side effects, so that the search of new therapeutic strategies is needed. The use of Poly-(ADP-ribose)-polymerase (PARP) inhibitors, although originally approved against BRCA-1 or BRCA-2 mutated cancers, has been extended, particularly in combination with other treatments, to cure cancers that do not display defects in DNA repair signaling pathways. The role of p53 oncosuppressor in the regulating the outcome of PARP inhibitor treatment remains an open issue. In this study, we addressed this topic by using a well-tolerated PARP 1/2/3 inhibitor, namely AZD2461, against colon cancer cell lines with different p53 status. We found that AZD2461 reduced cell proliferation in wtp53 and p53-/- cancer cells by increasing ROS and DNA damage, while R273H mutant (mut) p53 counteracted these effects. Moreover, AZD2461 improved the reduction of cell proliferation by low dose radiation (IR) in wtp53 cancer cells, in which a down-regulation of BRCA-1 occurred. AZD2461 did not affect cell proliferation of mutp53 colon cancer cells also in combination with low dose radiation, suggesting that only wt p53 or p53 null colon cancer cells could benefit AZD2461 treatment.

VPA and TSA Interrupt the Interplay between mutp53 and HSP70, Leading to CHK1 and RAD51 Down-Regulation and Sensitizing Pancreatic Cancer Cells to AZD2461 PARP Inhibitor.

HDAC inhibitors (HDACi) represent promising anti-cancer treatments, as the acetylation of histone and non-histone proteins is often dysregulated in cancer and contributes to cancer onset and progression. HDACi have been also reported to increase the cytotoxicity of DNA-damaging agents, such as radiation or cisplatin. In this study, we found that TSA and, even more effectively, VPA synergized with AZD2461, PARP1, 2 and 3 inhibitor (PARPi) to induce DNA damage and reduce pancreatic cancer cell survival. At a molecular level, VPA and TSA down-regulated CHK1 and RAD51, which is correlated with the interruption of the cross-talk between mutp53 and HSP70. Moreover, VPA and to a lesser extent TSA reactivated wtp53 in these cells, which contributed to CHK1 and RAD51 reduction. These findings suggest that the combination of HDACi and PARPi might improve the treatment of pancreatic cancer, which remains one of the most aggressive and therapy-resistant cancers.

Concomitant Inhibition of IRE1α/XBP1 Axis of UPR and PARP: A Promising Therapeutic Approach against c-Myc and Gammaherpesvirus-Driven B-Cell Lymphomas.

It is emerging that targeting the adaptive functions of Unfolded Protein Response (UPR) may represent a promising anti-cancer therapeutic approach. This is particularly relevant for B-cell lymphomas, characterized by a high level of constitutive stress due to high c-Myc expression. In this study, we found that IRE1α/XBP1 axis inhibition exerted a stronger cytotoxic effect compared to the inhibition of the other two UPR sensors, namely PERK and ATF6, in Burkitt lymphoma (BL) cells, in correlation with c-Myc downregulation. Interestingly, such an effect was more evident in Epstein-Barr virus (EBV)-negative BL cells or those cells expressing type I latency compared to type III latency BL cells. The other interesting finding of this study was that the inhibition of IRE1α/XBP1 downregulated BRCA-1 and RAD51 and potentiated the cytotoxicity of PARP inhibitor AZD2661 against BL cells and also against Primary Effusion Lymphoma (PEL), another aggressive B-cell lymphoma driven by c-Myc and associated with gammaherpesvirus infection. These results suggest that combining the inhibition of UPR sensors, particularly IRE1α/XBP1 axis, and molecules involved in DDR, such as PARP, could offer a new therapeutic opportunity for treating aggressive B-cell lymphomas such as BL and PEL.

Sialic Acid-Siglec Axis in Human Immune Regulation, Involvement in Autoimmunity and Cancer and Potential Therapeutic Treatments.

Siglecs are sialic acid-binding immunoglobulin-like lectins. Most Siglecs function as transmembrane receptors mainly expressed on blood cells in a cell type-specific manner. They recognize and bind sialic acids in specific linkages on glycoproteins and glycolipids. Since Sia is a self-molecule, Siglecs play a role in innate immune responses by distinguishing molecules as self or non-self. Increasing evidence supports the involvement of Siglecs in immune signaling representing immune checkpoints able to regulate immune responses in inflammatory diseases as well as cancer. Although further studies are necessary to fully understand the involvement of Siglecs in pathological conditions as well as their interactions with other immune regulators, the development of therapeutic approaches that exploit these molecules represents a tremendous opportunity for future treatments of several human diseases, as demonstrated by their application in several clinical trials. In the present review, we discuss the involvement of Siglecs in the regulation of immune responses, with particular focus on autoimmunity and cancer and the chance to target the sialic acid-Siglec axis as novel treatment strategy.

Preparation and In Vitro Evaluation of RITUXfab-Decorated Lipoplexes to Improve Delivery of siRNA Targeting C1858T PTPN22 Variant in B Lymphocytes.

Autoimmune endocrine disorders, such as type 1 diabetes (T1D) and thyroiditis, at present are treated with only hormone replacement therapy. This emphasizes the need to identify personalized effective immunotherapeutic strategies targeting T and B lymphocytes. Among the genetic variants associated with several autoimmune disorders, the C1858T polymorphism of the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene, encoding for Lyp variant R620W, affects the innate and adaptive immunity. We previously exploited a novel personalized immunotherapeutic approach based on siRNA delivered by liposomes (lipoplexes) that selectively inhibit variant allele expression. In this manuscript, we improved lipoplexes carrying siRNA for variant C1858T by functionalizing them with Fab of Rituximab antibody (RituxFab-Lipoplex) to specifically target B lymphocytes in autoimmune conditions, such as T1D. RituxFab-Lipoplexes specifically bind to B lymphocytes of the human Raji cell line and of human PBMC of healthy donors. RituxFab-Lipoplexes have impact on the function of B lymphocytes of T1D patients upon CpG stimulation showing a higher inhibitory effect on total cell proliferation and IgM+ plasma cell differentiation than the not functionalized ones. These results might open new pathways of applicability of RituxFab-Lipoplexes, such as personalized immunotherapy, to other autoimmune disorders, where B lymphocytes are the prevalent pathogenic immunocytes.

COVID-19: A Review on Diagnosis, Treatment, and Prophylaxis.

Coronavirus 2 (CoV) Severe Acute Respiratory Syndrome (SARS-CoV2) is causing a highly infectious pandemic pneumonia. Coronaviruses are positive sense single-stranded RNA viruses that infect several animal species, causing symptoms that range from those similar to the common cold to severe respiratory syndrome. The Angiotensin Converting Enzyme 2 (ACE2) is the SARS-CoV2 functional receptor. Measures are currently undertaken worldwide to control the infection to avoid disruption of the social and economic equilibrium, especially in countries with poor healthcare resources. In a guarded optimistic view, we hope that the undertaken preventive and treatment measures will at least contribute to contain viral diffusion, attenuate activity, or even eliminate SARS-CoV2. In this review, we discuss emerging perspectives for prevention/treatment of COVID-19 infection. In addition to vaccines under development, passive immunization is an open opportunity since patients develop neutralizing antibodies. A full spectrum of potential drugs for COVID-19 infections could in turn affect virus binding or enzymatic activities involved in viral replication and transcription. Furthermore, clinical trials are currently evaluating the safety and efficacy of anti-inflammatory drugs, such as tocilizumab. Bioinformatics may allow characterization of specific CD8+ and CD4+ T cell responses; thus, CoV2 T cells' frequency can be correlated with the disease severity and outcome. Combinatorial antibody phage display may be empowered to identify the immune repertoire of CoV2-specific neutralizing antibodies.

Loss of biliverdin reductase-A favors Tau hyper-phosphorylation in Alzheimer's disease.

Hyper-active GSK-3ß favors Tau phosphorylation during the progression of Alzheimer's disease (AD). Akt is one of the main kinases inhibiting GSK-3ß and its activation occurs in response to neurotoxic stimuli including, i.e., oxidative stress. Biliverdin reductase-A (BVR-A) is a scaffold protein favoring the Akt-mediated inhibition of GSK-3ß. Reduced BVR-A levels along with increased oxidative stress were observed early in the hippocampus of 3xTg-AD mice (at 6 months), thus suggesting that loss of BVR-A could be a limiting factor in the oxidative stress-induced Akt-mediated inhibition of GSK-3ß in AD. We evaluated changes of BVR-A, Akt, GSK-3ß, oxidative stress and Tau phosphorylation levels: (a) in brain from young (6-months) and old (12-months) 3xTg-AD mice; and (b) in post-mortem inferior parietal lobule (IPL) samples from amnestic mild cognitive impairment (MCI), from AD and from age-matched controls. Furthermore, similar analyses were performed in vitro in cells lacking BVR-A and treated with H2O2. Reduced BVR-A levels along with: (a) increased oxidative stress; (b) reduced GSK-3ß inhibition; and (c) increased Tau Ser404 phosphorylation (target of GSK-3ß activity) without changes of Akt activation in young mice, were observed. Similar findings were obtained in MCI, consistent with the notion that this is a molecular mechanism disrupted in humans. Interestingly, cells lacking BVR-A and treated with H2O2 showed reduced GSK-3ß inhibition and increased Tau Ser404 phosphorylation, which resulted from a defect of Akt and GSK-3ß physical interaction. Reduced levels of Akt/GSK-3ß complex were confirmed in both young 3xTg-AD and MCI brain. We demonstrated that loss of BVR-A impairs the neuroprotective Akt-mediated inhibition of GSK-3ß in response to oxidative stress, thus contributing to Tau hyper-phosphorylation in early stage AD. Such changes potential provide promising therapeutic targets for this devastating disorder.

Increased Mammalian Target of Rapamycin Signaling Contributes to the Accumulation of Protein Oxidative Damage in a Mouse Model of Down's Syndrome.

BACKGROUND: Neurodegenerative diseases are characterized by increased levels of oxidative stress and an altered mammalian target of rapamycin (mTOR)/autophagy axis; however, the mutual relationship between these two events is controversial. Previous studies in Down's syndrome (DS) and Alzheimer's disease (AD) suggested that the accumulation of protein oxidative damage results from the increased free radical production, mainly related to metabolic alterations, mitochondrial degeneration and amyloid-ß deposition, and aberrant activity of protein degradative systems. SUMMARY: This study analyzed mTOR signaling in Ts65Dn mice, a model of DS, at 6 and 12 months of age compared with euploid mice showing the early aberrant hyperphosphorylation of mTOR coupled with the reduction of autophagosome formation. Moreover, the evaluation of protein oxidation shows an increase in protein nitration and protein-bound 4-hydroxynonenal in 12-month-old Ts65Dn mice suggesting the potential involvement of altered autophagy in the buildup of protein oxidative damage. In addition, data obtained on cell culture support the protective role of autophagy in reducing protein oxidation. KEY MESSAGES: Overall, this study provides further evidence for the role of mTOR hyperactivation and reduced autophagy in the accumulation of protein oxidative damage during DS and AD pathologies.

ATF6 supports lysosomal function in tumor cells to enable ER stress-activated macroautophagy and CMA: impact on mutant TP53 expression.

The inhibition of the unfolded protein response (UPR), which usually protects cancer cells from stress, may be exploited to potentiate the cytotoxic effect of drugs inducing ER stress. However, in this study, we found that ER stress and UPR activation by thapsigargin or tunicamycin promoted the lysosomal degradation of mutant (MUT) TP53 and that the inhibition of the UPR sensor ATF6, but not of ERN1/IRE1 or EIF2AK3/PERK, counteracted such an effect. ATF6 activation was indeed required to sustain the function of lysosomes, enabling the execution of chaperone-mediated autophagy (CMA) as well as of macroautophagy, processes involved in the degradation of MUT TP53 in stressed cancer cells. At the molecular level, by pharmacological and genetic approaches, we demonstrated that the inhibition of ATF6 correlated with the activation of MTOR and with TFEB and LAMP1 downregulation in thapsigargin-treated MUT TP53 carrying cells. We hypothesize that the rescue of MUT TP53 expression by ATF6 inhibition, could further activate MTOR and maintain lysosomal dysfunction, further inhibiting MUT TP53 degradation, in a vicious circle. The findings of this study suggest that the presence of MUT TP53, which often exerts oncogenic properties, should be considered before approaching treatments combining ER stressors with ATF6 inhibitors against cancer cells, while it could represent a promising strategy against cancer cells that harbor WT TP53.

Mail-Order Pharmacy Dispensing of Mifepristone for Medication Abortion After In-Person Screening.

Importance: Before 2021, the US Food and Drug Administration required mifepristone to be dispensed in person, limiting access to medication abortion. Objective: To estimate the effectiveness, acceptability, and feasibility of dispensing mifepristone for medication abortion using a mail-order pharmacy. Design, Setting, and Participants: This prospective cohort study was conducted from January 2020 to May 2022 and included 11 clinics in 7 states (5 abortion clinics and 6 primary care sites, 4 of which were new to abortion provision). Eligible participants were seeking medication abortion at 63 or fewer days' gestation, spoke English or Spanish, were age 15 years or older, and were willing to take misoprostol buccally. After assessing eligibility for medication abortion through an in-person screening, mifepristone and misoprostol were prescribed using a mail-order pharmacy. Patients had standard follow-up care with the clinic. Clinical information was collected from medical records. Consenting participants completed online surveys about their experiences 3 and 14 days after enrolling. A total of 540 participants were enrolled; 10 withdrew or did not take medication. Data were analyzed from August 2022 to December 2023. Intervention: Mifepristone, 200 mg, and misoprostol, 800 µg, prescribed to a mail-order pharmacy and mailed to participants instead of dispensed in person. Main Outcomes and Measures: Proportion of patients with a complete abortion with medications only, reporting satisfaction with the medication abortion, and reporting timely delivery of medications. Results: Clinical outcome information was obtained and analyzed for 510 abortions (96.2%) among 506 participants (median [IQR] age, 27 [23-31] years; 506 [100%] female; 194 [38.3%] Black, 88 [17.4%] Hispanic, 141 [27.9%] White, and 45 [8.9%] multiracial/other individuals). Of these, 436 participants (85.5%; 95% CI, 82.2%-88.4%) received medications within 3 days. Complete abortion occurred after medication use in 499 cases (97.8%; 95% CI, 96.2%-98.9%). There were 24 adverse events (4.7%) for which care was sought for medication abortion symptoms; 3 patients (0.6%; 95% CI, 0.1%-1.7%) experienced serious adverse events requiring hospitalization (1 with blood transfusion); however, no adverse events were associated with mail-order dispensing. Of 477 participants, 431 (90.4%; 95% CI, 87.3%-92.9%) indicated that they would use mail-order dispensing again for abortion care, and 435 participants (91.2%; 95% CI, 88.3%-93.6%) reported satisfaction with the medication abortion. Findings were similar to those of other published studies of medication abortion with in-person dispensing. Conclusions and Relevance: The findings of this cohort study indicate that mail-order pharmacy dispensing of mifepristone for medication abortion was effective, acceptable to patients, and feasible, with a low prevalence of serious adverse events. This care model should be expanded to improve access to medication abortion services.

Acetylation increases expression, interaction with TRAPPC4 and surface localization of PD-L1.

PD-L1 is an immune checkpoint inhibitor, whose surface expression may be exploited by cancer cells to escape T cell-mediated immune recognition. PD-L1 expression and nuclear localization can be affected by epigenetic modifications, such as acetylation. In this study, we showed that VPA, a class I/IIa HDAC inhibitor, upregulated PD-L1 expression on the surface of pancreatic cancer cells. To this effect contributed the increased transcription, in correlation with histone acetylation of the PD-L1 gene and the acetylation of PD-L1 protein, which led to an increased interaction with TRAPPC4, molecule involved in PD-L1 recycling to the cell membrane. Interestingly, the BRD4 inhibitor JQ-1, counteracted PD-L1 transcription and reduced its surface expression, suggesting that such a combination could improve the outcome of VPA treatment, also because it increased the cytotoxic effect of VPA. Also considering that this HDACi did not upregulate PD-L2 and that the supernatant of VPA-treated cancer cells did not increase PD-L1 expression on the surface of macrophages exposed to it.

JQ-1/bortezomib combination strongly impairs MM and PEL survival by inhibiting c-Myc and mTOR despite the activation of prosurvival mechanisms.

Multiple myeloma (MM) and primary effusion lymphoma (PEL) are two aggressive hematologic cancers against which bortezomib and JQ-1, proteasome and bromodomain and extraterminal domain (BET) inhibitors, respectively, have been shown to have a certain success. However, the combination of both seems to be more promising than the single treatments against several cancers, including MM. Indeed, in the latter, proteasome inhibition upregulated nuclear respiratory factor 1 (NRF1), and such a prosurvival effect was counteracted by BET inhibitors. In the present study, we found that JQ-1/bortezomib induced a strong cytotoxic effect against PEL and discovered new insights into the cytotoxic mechanisms induced by such a drug combination in PEL and MM cells. In particular, a stronger c-Myc downregulation, leading to increased DNA damage, was observed in these cells after treatment with JQ-1/bortezomib than after treatment with the single drugs. Such an effect contributed to mechanistic target of rapamycin (mTOR)-phosphorylated eukaryotic translation initiation factor 4E-binding protein 1 (p-4EBP1) axis inhibition, also occurring through c-Myc downregulation. However, besides the prodeath effects, JQ-1/bortezomib activated unfolded protein response (UPR) and autophagy as prosurvival mechanisms. In conclusion, this study demonstrated that JQ-1/bortezomib combination could be a promising treatment for MM and PEL, unveiling new molecular mechanisms underlying its cytotoxic effect, and suggested that UPR and autophagy inhibition could be exploited to further potentiate the cytotoxicity of JQ-1/bortezomib.