Nickel-Catalyzed Gas-Free Reductive Carbonylation of Aryl Thianthrenium Salts to Access Aryl Amides and Aryl Thioesters

A nickel-catalyzed site-selective reductive carbonylation of arenes via aryl thianthrenium salts is described. Using Mo(CO)6 as a convenient solid CO source and reductant and employing nitroarenes and sulfonyl chlorides as readily available nitrogen and sulfur sources, a range of aryl amides and aryl thioesters were successfully synthesized in moderate to good yields. The utility of this transformation is demonstrated through the synthesis of antimicrobial agents and the late-stage functionalization of biorelevant molecules.

Endoplasmic reticulum stress disrupts signaling via altered processing of transmembrane receptors

Cell communication systems based on polypeptide ligands use transmembrane receptors to transmit signals across the plasma membrane. In their biogenesis, receptors depend on the endoplasmic reticulum (ER)-Golgi system for folding, maturation, transport and localization to the cell surface. ER stress, caused by protein overproduction and misfolding, is a well-known pathology in neurodegeneration, cancer and numerous other diseases. How ER stress affects cell communication via transmembrane receptors is largely unknown. In disease models of multiple myeloma, chronic lymphocytic leukemia and osteogenesis imperfecta, we show that ER stress leads to loss of the mature transmembrane receptors FGFR3, ROR1, FGFR1, LRP6, FZD5 and PTH1R at the cell surface, resulting in impaired downstream signaling. This is caused by downregulation of receptor production and increased intracellular retention of immature receptor forms. Reduction of ER stress by treatment of cells with the chemical chaperone tauroursodeoxycholic acid or by expression of the chaperone protein BiP resulted in restoration of receptor maturation and signaling. We show a previously unappreciated pathological effect of ER stress; impaired cellular communication due to altered receptor processing. Our findings have implications for disease mechanisms related to ER stress and are particularly important when receptor-based pharmacological approaches are used for treatment.

Bone Marrow-Targeted Liposomes Loaded with Bortezomib Overcome Multiple Myeloma Resistance

Multiple myeloma (MM) poses a significant therapeutic challenge due to its persistent progression and low survival rate. Although the proteasome inhibitor bortezomib has revolutionized MM treatment, MM aggressiveness and drug resistance remain critical concerns. To tackle this problem, we developed AMD3100-targeted Bortezomib Liposomes (ATBL) designed for the targeted delivery of bortezomib to MM cells. Uptake of ATBL into MM cells was dependent on CXCR4 and was enhanced compared to nontargeted liposomes, both in vitro and in vivo. Treating MM-bearing mice with ATBL achieved superior therapeutic efficacy compared to treatment with free bortezomib or nontargeted bortezomib-loaded liposomes. Notably, the therapeutic activity of ATBL was limited in mice inoculated with CXCR4-knockdown MM cells, highlighting CXCR4 as a potential biomarker for ATBL response. Importantly, ATBL was effective against an aggressive and bortezomib-resistant MM clone both in vitro and in vivo. Toxicity and biodistribution profiles demonstrated the safety and bone marrow-targeting ability of ATBL. Collectively, this study highlights ATBL as a promising next-generation proteasome inhibitor-based therapy that incorporates bone marrow-targeting ability and sensitizing elements to overcome drug resistance in MM.

Immunoproteasome as a Target for Prodrugs

Immunoproteasome (iCP) is a proteasome isoform that is expressed under inflammatory conditions such as cytokine interferon-γ exposure. The iCP has different catalytic subunits other than the standard CP (standard core particle), allowing the production of major histocompatibility complex class I (MHC-I) compatible peptides for eventual T-cell activation. We have previously reported the design of a fluorescent probe that monitors iCP activity in cells called TBZ-1, and we applied TBZ-1's iCP recognition sequence for prodrug release into iCP-active cells. Here, we demonstrate a proof-of-concept of the iCP as a prodrug release enzyme. The "payload" we utilized was a toxic moiety, doxorubicin, and a degrader for transcription factor, BRD4. Both examples show that iCP activity is required to elicit cell death or degradation of BRD4. This report highlights that the iCP is a viable prodrug target, and its activity can be used to release a variety of cargo in cells expressing the iCP.

Concurrent presentation of proliferative glomerulonephritis with monoclonal immunoglobulin deposits and light chain proximal tubulopathy: a case report and review of the literature

The simultaneous occurrence of proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) and light chain proximal tubulopathy (LCPT) presents a unique diagnostic and therapeutic challenge. PGNMID is characterized by monoclonal immunoglobulin deposition in glomeruli, leading to proliferative glomerular pathology, while LCPT involves monoclonal light chain deposition in proximal tubular cells, causing tubulointerstitial damage. Both conditions are classified under monoclonal gammopathy of renal significance (MGRS), but their coexistence in a single patient is exceedingly rare. This case report details the presentation of a patient with nephrotic syndrome and renal insufficiency, where renal biopsy revealed both PGNMID and LCPT. Treatment with bortezomib, cyclophosphamide, and dexamethasone achieved clinical remission and significant renal function recovery. This case emphasizes the critical role of renal biopsy in the diagnosis, particularly in the absence of detectable monoclonal proteins, and demonstrates the efficacy of targeted therapy in managing such complex renal pathologies. These findings contribute to a better understanding of MGRS and may guide future therapeutic strategies for similar cases.

Boron enabled bioconjugation chemistries

Novel bioconjugation reactions have been heavily pursued for the past two decades. A myriad of conjugation reactions have been developed for labeling molecules of interest in their native context as well as for constructing multifunctional molecular entities or stimuli-responsive materials. A growing cluster of bioconjugation reactions were realized by tapping into the unique properties of boron. As a rare element in human biology, boronic acids and esters exhibit remarkable biocompatibility. A number of organoboron reagents have been evaluated for bioconjugation, targeting the reactivity of either native biomolecules or those incorporating bioorthogonal functional groups. Owing to the dynamic nature of B-O and B-N bond formation, a significant portion of the boron-enabled bioconjugations exhibit rapid reversibility and accordingly have found applications in the development of reversible covalent inhibitors. On the other hand, stable bioconjugations have been developed that display fast kinetics and significantly expand the repertoire of bioorthogonal chemistry. This contribution presents a summary and comparative analysis of the recently developed boron-mediated bioconjugations. Importantly, this article seeks to provide an in-depth discussion of the thermodynamic and kinetic profiles of these boron-enabled bioconjugations, which reveals structure-reactivity relationships and provides guidelines for bioapplications.

Differential scanning calorimetric domain dissection for HSA upon interaction with Bortezomib: Unveiling the binding dynamics

Human serum albumin (HSA), a crucial plasma protein, plays a significant role in drug interactions within the bloodstream, bearing considerable clinical relevance. Bortezomib (BTZ) is a potent anti-cancer drug for multiple myeloma (MM) and mantle cell lymphoma (MC). The mechanism of BTZ transfer in the blood remains undetermined. This study aims to investigate the binding of BTZ to HSA using the techniques of differential scanning calorimetry (DSC), circular dichroism (CD), fluorescence spectroscopy, and computational methods such as molecular docking and molecular dynamics simulations. This study presents the thermal dissection of domain I (DI) of HSA by subjecting it to a temperature elevation of 79.2 °C (2 °C above Tm of DI) using DSC, which provides new information on the thermal behavior of HSA domains. Furthermore, the deconvolution analysis of the HSA thermogram in the absence and presence of BTZ revealed that the drug binding site is located in DI and impacts DII. The interaction between BTZ and HSA with a binding affinity (Kb) of 7.744±0.2 ×105 M-1 influences protein dynamics and reduces HSA's thermal stability by almost 1 °C. This study is crucial for predicting the pharmacokinetics and pharmacodynamics of BTZ, aiding in developing safer and more effective treatments for MM and MC.

Bortezomib in cancer therapy: Mechanisms, side effects, and future proteasome inhibitors

The ubiquitin-proteasome pathway (UPP) regulates protein stability and normal cellular functions with the help of autocatalytic proteasome complex. Studies have linked aberrant proteasome activity to malignant cells and found that proteasome inhibitors play a significant role as therapeutic drugs for various types of cancer, specifically multiple myeloma and mantle cell lymphoma. Bortezomib, the first FDA-approved proteasome inhibitor for treating different stages of multiple myeloma, acts on cancer cells by inhibiting the 26S proteasome, modulating NF-κB, phosphorylating Bcl-2, upregulating of NOXA, blocking p53 degradation, activating caspase, generating reactive oxygen species (ROS), and inhibiting angiogenesis. However, its efficacy is limited due to side effects such as peripheral neuropathy (PN), thrombotic microangiopathy (TMA), and acute interstitial nephritis (AIN). Therefore, a better understanding of its precise mechanism of action may help mitigate these side effects. In this review, we have discussed the proposed mechanisms of action and off target effects of Bortezomib, along with the prospects of next generation potential proteasome inhibitor drugs in the treatment of cancer.

Deoxygenative Geminal Silylboration of Amides Using Silylboronates: Synthesis and Use of α-Boryl-α-Silylalkylamines

α-Silylalkylamines and α-borylalkylamines are versatile synthetic intermediates and attractive scaffolds found in pharmaceutical drugs and agrochemicals. Despite great progress on synthetic methods for preparation of α-silylalkylamines or α-borylalkylamines, there are no general strategies for preparation of α-boryl-α-silylalkylamines and the reactivity has not been explored. Here we report deoxygenative geminal silylboration of amides using silylboronates in the presence of alkoxide base catalyst, producing α-boryl-α-silylalkylamines. The silicon and boron groups in α-boryl-α-silylalkylamines are found to be utilized to chemoselective transformations, such as protonation and alkylation. This protocol serves various α-silylalkylamines and α-borylalkylamines from readily available amides.

Factors determining the sensitivity to proteasome inhibitors of multiple myeloma cells

Multiple myeloma is an incurable cancer that originates from antibody-producing plasma cells. It is characterized by an intrinsic ability to produce large amounts of immunoglobulin-like proteins. The high rate of synthesis makes myeloma cells dependent on protein processing mechanisms related to the proteasome. This dependence made proteasome inhibitors such as bortezomib and carfilzomib one of the most important classes of drugs used in multiple myeloma treatment. Inhibition of the proteasome is associated with alteration of a number of important biological processes leading, in consequence, to inhibition of angiogenesis. The effect of drugs in this group and the degree of patient response to the treatment used is itself an extremely complex process that depends on many factors. At cellular level the change in sensitivity to proteasome inhibitors may be related to differences in the expression level of proteasome subunits, the degree of proteasome loading, metabolic adaptation, transcriptional or epigenetic factors. These are just some of the possibilities that may influence differences in response to proteasome inhibitors. This review describes the main cellular factors that determine the degree of response to proteasome inhibitor drugs, as well as information on the key role of the proteasome and the performance characteristics of the inhibitors that are the mainstay of multiple myeloma treatment.

Autophagy and oxidative stress modulation mediate Bortezomib resistance in prostate cancer

Proteasome inhibitors such as Bortezomib represent an established type of targeted treatment for several types of hematological malignancies, including multiple myeloma, Waldenstrom's macroglobulinemia, and mantle cell lymphoma, based on the cancer cell's susceptibility to impairment of the proteasome-ubiquitin system. However, a major problem limiting their efficacy is the emergence of resistance. Their application to solid tumors is currently being studied, while simultaneously, a wide spectrum of hematological cancers, such as Myelodysplastic Syndromes show minimal or no response to Bortezomib treatment. In this study, we utilize the prostate cancer cell line DU-145 to establish a model of Bortezomib resistance, studying the underlying mechanisms. Evaluating the resulting resistant cell line, we observed restoration of proteasome chymotrypsin-like activity, regardless of drug presence, an induction of pro-survival pathways, and the substitution of the Ubiquitin-Proteasome System role in proteostasis by induction of autophagy. Finally, an estimation of the oxidative condition of the cells indicated that the resistant clones reduce the generation of reactive oxygen species induced by Bortezomib to levels even lower than those induced in non-resistant cells. Our findings highlight the role of autophagy and oxidative stress regulation in Bortezomib resistance and elucidate key proteins of signaling pathways as potential pharmaceutical targets, which could increase the efficiency of proteasome-targeting therapies, thus expanding the group of molecular targets for neoplastic disorders.

Optimal strategies of oncolytic virus-bortezomib therapy via the apoptotic, necroptotic, and oncolysis signaling network

Bortezomib and oncolytic virotherapy are two emerging targeted cancer therapies. Bortezomib, a proteasome inhibitor, disrupts protein degradation in cells, leading to the accumulation of unfolded proteins that induce apoptosis. On the other hand, virotherapy uses genetically modified oncolytic viruses (OVs) to infect cancer cells, trigger cell lysis, and activate anti-tumor response. Despite progress in cancer treatment, identifying administration protocols for therapeutic agents remains a significant concern, aiming to strike a balance between efficacy, minimizing toxicity, and administrative costs. In this work, optimal control theory was employed to design a cost-effective and efficient co-administration protocols for bortezomib and OVs that could significantly diminish the population of cancer cells via the cell death program with the NF$ \kappa $B-BAX-RIP1 signaling network. Both linear and quadratic control strategies were explored to obtain practical treatment approaches by adapting necroptosis protocols to efficient cell death programs. Our findings demonstrated that a combination therapy commencing with the administration of OVs followed by bortezomib infusions yields an effective tumor-killing outcome. These results could provide valuable guidance for the development of clinical administration protocols in cancer treatment.

Contribution of HSP90 Cleavage to the Cytotoxic Effect of Suberoylanilide Hydroxamic Acid In Vivo and the Involvement of TXNIP in HSP90 Cleavage

Heat shock protein (HSP) 90 is expressed in most living organisms, and several client proteins of HSP90 are necessary for cancer cell survival and growth. Previously, we found that HSP90 was cleaved by histone deacetylase (HDAC) inhibitors and proteasome inhibitors, and the cleavage of HSP90 contributes to their cytotoxicity in K562 leukemia cells. In this study, we first established mouse xenograft models with K562 cells expressing the wild-type or cleavage-resistant mutant HSP90β and found that the suppression of tumor growth by the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was interrupted by the mutation inhibiting the HSP90 cleavage in vivo. Next, we investigated the possible function of thioredoxin interacting protein (TXNIP) in the HSP90 cleavage induced by SAHA. TXNIP is a negative regulator for thioredoxin, an antioxidant protein. SAHA transcriptionally induced the expression of TXNIP in K562 cells. HSP90 cleavage was induced by SAHA also in the thymocytes of normal mice and suppressed by an anti-oxidant and pan-caspase inhibitor. When the thymocytes from the TXNIP knockout mice and their wild-type littermate control mice were treated with SAHA, the HSP90 cleavage was detected in the thymocytes of the littermate controls but suppressed in those of the TXNIP knockout mice suggesting the requirement of TXNIP for HSP90 cleavage. We additionally found that HSP90 cleavage was induced by actinomycin D, β-mercaptoethanol, and p38 MAPK inhibitor PD169316 suggesting its prevalence. Taken together, we suggest that HSP90 cleavage occurs also in vivo and contributes to the anti-cancer activity of various drugs in a TXNIP-dependent manner.

Optimized Liposomal Delivery of Bortezomib for Advancing Treatment of Multiple Myeloma

Bortezomib (BTZ), a boronic acid-derived proteasome inhibitor, is commonly employed in treating multiple myeloma (MM). However, the applications of BTZ are limited due to its poor stability and low bioavailability. Herein, we develop an optimized liposomal formulation of BTZ (L-BTZ) by employing a remote-loading strategy. This formulation uses Tiron, a divalent anionic catechol derivative, as the internal complexing agent. Compared to earlier BTZ-related formulations, this alternative formulation showed significantly greater stability due to the Tiron-BTZ complex's higher pH stability and negative charges, compared to the meglumine-BTZ complex. Significantly, the plasma AUC of L-BTZ was found to be 30 times greater than that of free BTZ, suggesting an extended blood circulation duration. In subsequent therapeutic evaluations using two murine xenograft tumor models of MM, the NCI-H929 and OPM2 models showed tumor growth inhibition (TGI) values of 37% and 57%, respectively. In contrast, free BTZ demonstrated TGI values of 17% and 11% in these models. Further, L-BTZ presented enhanced antitumor efficacy in the Hepa1-6 HCC syngeneic model, indicating its potential broader applicability as an antineoplastic agent. These findings suggest that the optimized L-BTZ formulation offers a significant advancement in BTZ delivery, holding substantial promise for clinical investigation in not merely MM, but other cancer types.

ABPP-CoDEL: Activity-Based Proteome Profiling-Guided Discovery of Tyrosine-Targeting Covalent Inhibitors from DNA-Encoded Libraries

DNA-encoded chemical library (DEL) has been extensively used for lead compound discovery for decades in academia and industry. Incorporating an electrophile warhead into DNA-encoded compounds recently permitted the discovery of covalent ligands that selectively react with a particular cysteine residue. However, noncysteine residues remain underexplored as modification sites of covalent DELs. Herein, we report the design and utility of tyrosine-targeting DELs of 67 million compounds. Proteome-wide reactivity analysis of tyrosine-reactive sulfonyl fluoride (SF) covalent probes suggested three enzymes (phosphoglycerate mutase 1, glutathione s-transferase 1, and dipeptidyl peptidase 3) as models of tyrosine-targetable proteins. Enrichment with SF-functionalized DELs led to the identification of a series of tyrosine-targeting covalent inhibitors of the model enzymes. In-depth mechanistic investigation revealed their novel modes of action and reactive ligand-accessible hotspots of the enzymes. Our strategy of combining activity-based proteome profiling and covalent DEL enrichment (ABPP-CoDEL), which generated selective covalent binders against a variety of target proteins, illustrates the potential use of this methodology in further covalent drug discovery.

Natural Products-Pyrazine Hybrids: A Review of Developments in Medicinal Chemistry

Pyrazine is a six-membered heterocyclic ring containing nitrogen, and many of its derivatives are biologically active compounds. References have been downloaded through Web of Science, PubMed, Science Direct, and SciFinder Scholar. The structure, biological activity, and mechanism of natural product derivatives containing pyrazine fragments reported from 2000 to September 2023 were reviewed. Publications reporting only the chemistry of pyrazine derivatives are beyond the scope of this review and have not been included. The results of research work show that pyrazine-modified natural product derivatives have a wide range of biological activities, including anti-inflammatory, anticancer, antibacterial, antiparasitic, and antioxidant activities. Many of these derivatives exhibit stronger pharmacodynamic activity and less toxicity than their parent compounds. This review has a certain reference value for the development of heterocyclic compounds, especially pyrazine natural product derivatives.

Development of AMBER Parameters for Molecular Simulations of Selected Boron-Based Covalent Ligands

Boron containing compounds (BCCs) aroused increasing interest in the scientific community due to their wide application as drugs in various fields. In order to design new compounds hopefully endowed with pharmacological activity and also investigate their conformational behavior, the support of computational studies is crucial. Nevertheless, the suitable molecular mechanics parameterization and the force fields needed to perform these simulations are not completely available for this class of molecules. In this paper, Amber force field parameters for phenyl-, benzyl-, benzylamino-, and methylamino-boronates, a group of boron-containing compounds involved in different branches of the medicinal chemistry, were created. The robustness of the obtained data was confirmed through molecular dynamics simulations on ligand/β-lactamases covalent complexes. The ligand torsional angles, populated over the trajectory frames, were confirmed by values found in the ligand geometries, located through optimizations at the DFT/B3LYP/6-31g(d) level, using water as a solvent. In summary, this study successfully provided a library of parameters, opening the possibility to perform molecular dynamics simulations of this class of boron-containing compounds.

MiR-672-5p-Mediated Upregulation of REEP6 in Spinal Dorsal Horn Participates in Bortezomib-Induced Neuropathic Pain in Rats

Evidence shows that miRNAs are deeply involved in nervous system diseases, but whether miRNAs contribute to the bortezomib (BTZ)-induced neuropathic pain remains unclear. We aimed to investigate whether miRNAs contribute to bortezomib (BTZ)-induced neuropathic pain and explore the related downstream cascades. The level of miRNAs in the spinal dorsal horn was explored using miRNA microarray and PCR. MiR-672-5p was significantly downregulated in dorsal horn neurons in the rats with BTZ treatment. Intrathecal injection of miR-672-5p agomir blunted the increase of the amplitude and frequency of sEPSCs in dorsal horn neurons and mechanical allodynia induced by BTZ. In addition, the knockdown of miR-672-5p by intrathecal injection of antagomir increased the amplitude and frequency of sEPSCs in dorsal horn neurons and decreased the mechanical withdrawal threshold in naïve rats. Furthermore, silico analysis and the data from subsequent assays indicated that REEP6, a potential miR-672-5p-regulating molecule, was increased in the spinal dorsal horn of rats with BTZ-induced neuropathic pain. Blocking REEP6 alleviated the mechanical pain behavior induced by BTZ, whereas overexpressing REEP6 induced pain hypersensitivity in naïve rats. Importantly, we further found that miR-672-5p was expressed in the REEP6-positive cells, and overexpression or knockdown of miR-672-5p reversely regulated the REEP6 expression. Bioinformatics analysis and double-luciferase reporter assay showed the existence of interaction sites between REEP6 mRNA and miR-672-5p. Overall, our study demonstrated that miR-672-5p directly regulated the expression of REEP6, which participated in the neuronal hyperexcitability in the spinal dorsal horn and neuropathic pain following BTZ treatment. This signaling pathway may potentially serve as a novel therapeutic avenue for chemotherapeutic-induced mechanical hypersensitivity.

Advances in covalent drug discovery

Covalent drugs have been used to treat diseases for more than a century, but tools that facilitate the rational design of covalent drugs have emerged more recently. The purposeful addition of reactive functional groups to existing ligands can enable potent and selective inhibition of target proteins, as demonstrated by the covalent epidermal growth factor receptor (EGFR) and Bruton's tyrosine kinase (BTK) inhibitors used to treat various cancers. Moreover, the identification of covalent ligands through 'electrophile-first' approaches has also led to the discovery of covalent drugs, such as covalent inhibitors for KRAS(G12C) and SARS-CoV-2 main protease. In particular, the discovery of KRAS(G12C) inhibitors validates the use of covalent screening technologies, which have become more powerful and widespread over the past decade. Chemoproteomics platforms have emerged to complement covalent ligand screening and assist in ligand discovery, selectivity profiling and target identification. This Review showcases covalent drug discovery milestones with emphasis on the lessons learned from these programmes and how an evolving toolbox of covalent drug discovery techniques facilitates success in this field.

Integrative transcriptome analysis of SARS-CoV-2 human-infected cells combined with deep learning algorithms identifies two potential cellular targets for the treatment of coronavirus disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) quickly spread worldwide, leading coronavirus disease 2019 (COVID-19) to hit pandemic level less than 4 months after the first official cases. Hence, the search for drugs and vaccines that could prevent or treat infections by SARS-CoV-2 began, intending to reduce a possible collapse of health systems. After 2 years, efforts to find therapies to treat COVID-19 continue. However, there is still much to be understood about the virus' pathology. Tools such as transcriptomics have been used to understand the impact of SARS-CoV-2 on different cells isolated from various tissues, leaving datasets in the databases that integrate genes and differentially expressed pathways during SARS-CoV-2 infection. After retrieving transcriptome datasets from different human cells infected with SARS-CoV-2 available in the database, we performed an integrative analysis associated with deep learning algorithms to determine differentially expressed targets mainly after infection. The targets found represented a fructose transporter (GLUT5) and a component of proteasome 26s. These targets were then molecularly modeled, followed by molecular docking that identified potential inhibitors for both structures. Once the inhibition of structures that have the expression increased by the virus can represent a strategy for reducing the viral replication by selecting infected cells, associating these bioinformatics tools, therefore, can be helpful in the screening of molecules being tested for new uses, saving financial resources, time, and making a personalized screening for each infectious disease.

Targeting Key Signaling Pathways in Glioblastoma Stem Cells for the Development of Efficient Chemo- and Immunotherapy

Glioblastoma multiforme (GBM) is the most aggressive and most common malignant brain tumor with poor patient survival despite therapeutic intervention. On the cellular level, GBM comprises a rare population of glioblastoma stem cells (GSCs), driving therapeutic resistance, invasion, and recurrence. GSCs have thus come into the focus of therapeutic strategies, although their targeting remains challenging. In the present study, we took advantage of three GSCs-populations recently established in our lab to investigate key signaling pathways and subsequent therapeutic strategies targeting GSCs. We observed that NF-κB, a crucial transcription factor in GBM progression, was expressed in all CD44+/CD133+/Nestin+-GSC-populations. Exposure to TNFα led to activation of NF-κB-RELA and/or NF-κB-c-REL, depending on the GBM type. GSCs further expressed the proto-oncogene MYC family, with MYChigh GSCs being predominantly located in the tumor spheres ("GROW"-state) while NF-κB-RELAhigh GSCs were migrating out of the sphere ("GO"-state). We efficiently targeted GSCs by the pharmacologic inhibition of NF-κB using PTDC/Bortezomib or inhibition of MYC by KJ-Pyr-9, which significantly reduced GSC-viability, even in comparison to the standard chemotherapeutic drug temozolomide. As an additional cell-therapeutic strategy, we showed that NK cells could kill GSCs. Our findings offer new perspectives for developing efficient patient-specific chemo- and immunotherapy against GBM.

Proteasome Inhibitors and Their Potential Applicability in Osteosarcoma Treatment

Simple Summary

Bone cancer has seen minimal benefits in therapeutic options in the past 30 years. Proteasome inhibitors present a new avenue of research for the treatment of bone cancer. Proteasome inhibitors impair the function of the proteasome, a structure within the cell that removes unwanted and misfolded proteins. Bone cancer cells heavily rely on the proteasome to properly function and survive. Impairing the proteasome function can have detrimental consequences and lead to cell death. This review provides a thorough summary of the in vitro, in vivo, and clinical research that has explored proteasome inhibitors for the treatment of bone cancer.

Abstract

Osteosarcoma (OS) is the most common type of bone cancer, with ~30% of patients developing secondary/metastatic tumors. The molecular complexity of tumor metastasis and the lack of effective therapies for OS has cultivated interest in exploiting the proteasome as a molecular target for anti-cancer therapy. As our understanding towards the behavior of malignant cells expands, it is evident that cancerous cells display a greater reliance on the proteasome to maintain homeostasis and sustain efficient biological activities. This led to the development and approval of first- and second-generation proteasome inhibitors (PIs), which have improved outcomes for patients with multiple myeloma and mantle cell lymphoma. Researchers have since postulated the therapeutic potential of PIs for the treatment of OS. As such, this review aims to summarize the biological effects and latest findings from clinical trials investigating PI-based treatments for OS. Integrating PIs into current treatment regimens may better outcomes for patients diagnosed with OS.

Activity Screening of Fatty Acid Mimetic Drugs Identified Nuclear Receptor Agonists

Fatty acid mimetics (FAM) are bioactive molecules acting through the binding sites of endogenous fatty acid metabolites on enzymes, transporters, and receptors. Due to the special characteristics of these binding sites, FAMs share common chemical features. Pharmacological modulation of fatty acid signaling has therapeutic potential in multiple pathologies, and several FAMs have been developed as drugs. We aimed to elucidate the promiscuity of FAM drugs on lipid-activated transcription factors and tested 64 approved compounds for activation of RAR, PPARs, VDR, LXR, FXR, and RXR. The activity screening revealed nuclear receptor agonism of several FAM drugs and considerable promiscuity of NSAIDs, while other compound classes evolved as selective. These screening results were not anticipated by three well-established target prediction tools, suggesting that FAMs are underrepresented in bioactivity data for model development. The screening dataset may therefore valuably contribute to such tools. Oxaprozin (RXR), tianeptine (PPARδ), mycophenolic acid (RAR), and bortezomib (RAR) exhibited selective agonism on one nuclear receptor and emerged as attractive leads for the selective optimization of side activities. Additionally, their nuclear receptor agonism may contribute relevant and valuable polypharmacology.

Access to Unexplored 3D Chemical Space: cis ‐Selective Arene Hydrogenation for the Synthesis of Saturated Cyclic Boronic Acids

A new class of saturated boron‐incorporated cyclic molecules has been synthesized employing an arene‐hydrogenation methodology. cis‐Selective hydrogenation of easily accessible, and biologically important molecules comprising benzoxaborole, benzoxaborinin, and benzoxaboripin derivatives is reported. Among the various catalysts tested, rhodium cyclic(alkyl)(amino)carbene [Rh‐CAAC] (1) pre‐catalyst revealed the best hydrogenation activity confirming turnover number up to 1400 with good to high diastereoselectivity. A broad range of functional groups was tolerated including sensitive substituents such as −F, −CF₃, and −silyl groups. The utility of the synthesized products was demonstrated by the recognition of diols and sugars under physiological conditions. These motifs can have a substantial importance in medicinal chemistry as they possess a three‐dimensional structure, are highly stable, soluble in water, form hydrogen bonds, and interact with diols and sugars.

Severe cellular stress drives apoptosis through a dual control mechanism independently of p53

For past two decades, p53 has been claimed as the primary sensor initiating apoptosis. Under severe cellular stress, p53 transcriptional activity activates BH3-only proteins such as Bim, Puma, or Noxa to nullify the inhibitory effects of anti-apoptotic proteins on pro-apoptotic proteins for mitochondrial outer membrane permeabilization. Cellular stress determines the expression level of p53, and the amount of p53 corresponds to the magnitude of apoptosis. However, our studies indicated that Bim and Puma are not the target genes of p53 in three cancer models, prostate cancer, glioblastoma, and osteosarcoma. Bim counteracted with Bcl-xl to activate apoptosis independently of p53 in response to doxorubicin-induced severe DNA damage in prostate cancer. Moreover, the transcriptional activity of p53 was more related to cell cycle arrest other than apoptosis for responding to DNA damage stress generated by doxorubicin in prostate cancer and glioblastoma. A proteasome inhibitor that causes protein turnover dysfunction, bortezomib, produced apoptosis in a p53-independent manner in glioblastoma and osteosarcoma. p53 in terms of both protein level and nuclear localization in combining doxorubicin with bortezomib treatment was obviously lower than when using DOX alone, inversely correlated with the magnitude of apoptosis in glioblastoma. Using a BH3-mimetic, ABT-263, to treat doxorubicin-sensitive p53-wild type and doxorubicin-resistant p53-null osteosarcoma cells demonstrated only limited apoptotic response. The combination of doxorubicin or bortezomib with ABT-263 generated a synergistic outcome of apoptosis in both p53-wild type and p53-null osteosarcoma cells. Together, this suggested that p53 might have no role in doxorubicin-induced apoptosis in prostate cancer, glioblastoma and osteosarcoma. The effects of ABT-263 in single and combination treatment of osteosarcoma or prostate cancer indicated a dual control to regulate apoptosis in response to severe cellular stress. Whether our findings only apply in these three types of cancers or extend to other cancer types remains to be explored.

Compound cellular stress maximizes apoptosis independently of p53 in glioblastoma

We examined the apoptotic response of two glioblastoma cells, p53 wild type U87 and p53 mutated T98G, to doxorubicin, bortezomib, and vorinostat, which respectively target DNA, 26S proteasome and histone deacetylase, to clarify p53's function in apoptosis. We demonstrated that doxorubicin induced apoptosis in U87 cells but not in T98G cells. The level of p53 was definitively correlated to the extent of DNA damage and apoptosis initiation. Dominant-negative p53 reduced p21 expression, but did not affect doxorubicin-induced apoptosis, so the transcriptional activity of p53 seemed not to participate in doxorubicin-induced apoptosis. However, p53 concentrated into the nucleus during heavy apoptosis. Bortezomib could induce apoptosis in U87 with high sensitivity and T98G cells with low sensitivity. In contrast, vorinostat promoted apoptosis in both U87 and T98G cells and reduced the basal level of p53 in U87 cells, indicating that p53 played no role in the vorinostat-induced apoptosis. To clearly define the role of p53 in bortezomib- and doxorubicin-induced apoptosis, we combined doxorubicin with bortezomib to treat U87 cells to assess this combination's effect on apoptosis and p53 status. Interestingly, the combination of doxorubicin with bortezomib engendered compound stress, resulting in a synergistic outcome for apoptosis in U87 cells. However, the amounts of p53 in the total count and in the nucleus were much lower with the combination than with doxorubicin alone, suggesting that p53 played no role in either the compound stress, doxorubicin-only or bortezomib-induced apoptosis.

Treatment with bortezomib for recurrent proliferative glomerulonephritis with monoclonal IgG deposits in kidney allograft. Case report and review of the literature

Proliferative glomerulonephritis with monoclonal immunoglobulin IgG deposits (PGNMID) is an already described form of renal involvement by monoclonal gammopathy. PGNMID is known to recur in kidney allografts. Bortezomib has shown clinical success in the treatment of multiple myeloma. However, its effect for recurrent PGNMID in kidney allografts has rarely been reported. We present the case of a 61-year-old woman who developed recurrent PGNMID 3 weeks after kidney transplantation. This patient was initially treated with steroid pulses (500 mg/day for 2 days) and two cycles of rituximab therapy (200 mg/body). However, disease progression was observed with mesangial matrix expansion and subendothelial deposits by light microscopy and stronger staining for IgG3 and kappa in the mesangial area by Immunofluorescence (IF) microscopy. Thus, we started treatment with bortezomib therapy (1.3 mg/m2, once weekly, on days 1, 8, 15, and 22 in a 5-week cycle, for a total of six cycles). Bortezomib therapy reduced massive proteinuria, although monoclonal immune deposits on IF and the serum creatinine level did not change during the treatment period. Seven months after completion of the first bortezomib course, we decided to prescribe a second course of bortezomib with the same regimen. Each course resulted in a > 50% reduction of proteinuria. Bortezomib may delay the progress of PGNMID in kidney allograft patients.

Bortezomib-Induced Epigenetic Alterations in Nerve Cells: Focus on the Mechanisms Contributing to the Peripheral Neuropathy Development

Bortezomib-induced peripheral neuropathy (BiPN) occurs in approximately 40% of patients with multiple myeloma. The induction of severe neuropathy entails the dose reduction or complete elimination of bortezomib (BTZ). Interestingly, discontinuation of BTZ mostly results in a reduction or complete resolution of peripheral neuropathy (PN) symptoms. Therefore, it is likely that the BiPN mechanisms are based on temporary/reversible changes such as epigenetic alterations. In this study, we examined the effect of treating nerve cells, differentiated from the Lund human mesencephalic (dLUHMES) cell line, with several low-dose BTZ (0.15 nM) applications. We showed a significant decrease in global histone H3 acetylation as well as histone H3 lysine 9 acetylation. Moreover, analysis of the genetic microarray showed changes mainly in epigenetic processes related to chromatin rearrangement, chromatin silencing, and gene silencing. GSEA analysis revealed three interesting signaling pathways (SIRT1, B-WICH and, b-Catenin) that may play a pivotal role in PN development. We also performed an analysis of the miRNA microarray which showed the interactions of miR-6810-5p with the genes MSN, FOXM1, TSPAN9, and SLC1A5, which are directly involved in neuroprotective processes, neuronal differentiation, and signal transduction. The study confirmed the existence of BTZ-induced complex epigenetic alterations in nerve cells. However, further studies are necessary to assess the reversibility of epigenetic changes and their potential impact on the induction/resolution of PN.

Pyrazine and Phenazine Heterocycles: Platforms for Total Synthesis and Drug Discovery

There are numerous pyrazine and phenazine compounds that demonstrate biological activities relevant to the treatment of disease. In this review, we discuss pyrazine and phenazine agents that have shown potential therapeutic value, including several clinically used agents. In addition, we cover some basic science related to pyrazine and phenazine heterocycles, which possess interesting reactivity profiles that have been on display in numerous cases of innovative total synthesis approaches, synthetic methodologies, drug discovery efforts, and medicinal chemistry programs. The majority of this review is focused on presenting instructive total synthesis and medicinal chemistry efforts of select pyrazine and phenazine compounds, and we believe these incredible heterocycles offer promise in medicine.

Sensors to the Diagnostic Assessment of Anticancer and Antimicrobial Therapies Effectiveness by Drugs a with Pyrazine Scaffold

Treatment with pyrazine derivatives—antituberculosis pyrazinamide (PZA), anticancer bortezomib (BZM), and antifungal pyrazine-2-amidoxime (PAOX) and pyrazine-2-thiocarboxamide (PTCA)—is associated with side effects, as observed in the case of other therapeutic drugs. To prevent the side effects of pyrazine derivatives, researchers are working to develop a universal method that will detect these compounds in body fluids. There is a lack of literature data about voltammetric measurements with poly-L-amino acid-modified GCEs surfaces. The available reports describe the application of various modifications of these electrodes for the detection of different active substances of drugs; however, they do not indicate one particular method for the detection of drugs with a pyrazine skeleton. This research aimed to prepare three types of glassy carbon electrodes (GCEs) with modified surfaces by electropolymerization using 1, 10, and 100 mM solutions of L-glycine (Gly), L-alanine (Ala), L-lysine (Lys), respectively. The poly-amino acid coatings applied on GCE surfaces were analyzed in detail under a three-dimensional (3D) microscope and were used as chemosensors of four pyrazine drugs in stoichiometric tests. The results were compared with the measurements made on an unmodified GCE. To obtain reliable results, the linearity of measurements was also verified in the concentration gradient and appropriate scanning speed was chosen to achieve the most accurate measurements.

A general synthesis of aromatic amides via palladium-catalyzed direct aminocarbonylation of aryl chlorides

Aryl amines made easy by palladium-catalyzed aminocarbonylation of aryl chlorides.

Severe cellular stress activates apoptosis independently of p53 in osteosarcoma

Apoptosis induced by doxorubicin, bortezomib, or paclitaxel, targeting DNA, 26S proteasome, and microtubules respectively, was assessed in two osteosarcoma cells, p53 wild-type U2OS and p53-null MG63 cells. Doxorubicin-induced apoptosis only occurred in U2OS, not in MG63. In contrast, bortezomib and paclitaxel could drive U2OS or MG63 toward apoptosis effectively, suggesting that apoptosis induced by bortezomib or paclitaxel is p53-independent. The expressions of Bcl2 family members such as Bcl2, Bcl-xl, and Puma could be seen in U2OS and MG63 cells with or without doxorubicin, bortezomib, or paclitaxel treatment. In contrast, another member, Bim, only could be observed in U2OS, not in MG63, under the same conditions. Bim knockdown did not affect the doxorubicin-induced apoptosis in U2OS, suggested that a BH3-only protein other than Bim might participate in apoptosis induced by doxorubicin. Using a BH3-mimetic, ABT-263, to inhibit Bcl2 or Bcl-xl produced a limited apoptotic response in U2OS and MG63 cells, suggesting that this BH3-mimetic cannot activate the Bax/Bak pathway efficiently. Significantly, ABT-263 enhanced doxorubicin- and bortezomib-induced apoptosis synergistically in U2OS and MG63 cells. These results implied that the severe cellular stress caused by doxorubicin or bortezomib might be mediated through a dual process to control apoptosis. Respectively, doxorubicin or bortezomib activates a BH3-only protein in one way and corresponding unknown factors in another way to affect mitochondrial outer membrane permeability, resulting in apoptosis. The combination of doxorubicin with ABT-263 could produce synergistic apoptosis in MG63 cells, which lack p53, suggesting that p53 has no role in doxorubicin-induced apoptosis in osteosarcoma. In addition, ABT-263 enhanced paclitaxel to induce moderate levels of apoptosis.

Transplantation and immunosuppression: a review of novel transplant-related immunosuppressant drugs

Immunosuppressive drugs used in the transplantation period are generally defined as induction and maintenance therapy. The use of immunosuppressants, which are particularly useful and have fewer side effects, decreased both mortality and morbidity. Many drugs such as steroids, calcineurin inhibitors (cyclosporine-A, tacrolimus), antimetabolites (mycophenolate mofetil, azathioprine), and mTOR inhibitors (sirolimus, everolimus) are used as immunosuppressive agents. Although immunosuppressant drugs cause many side effects such as hypertension, infection, and hyperlipidemia, they are the agents that should be used to prevent organ rejection. This shows the importance of individualized drug use. The optimal immunosuppressive therapy post-transplant is not established. Therefore, discovering less toxic but more potent new agents is of great importance, and new experimental and clinical studies are needed in this regard.Our review discussed the mechanism of immunosuppressants, new agents' discovery, and current therapeutic protocols in the transplantation.

Recent Developments in the Practical Application of Novel Carboxylic Acid Bioisosteres

BACKGROUND

The carboxylic acid is an important functional group which features in the pharmacophore of some 450 drugs. Unfortunately, some carboxylic acid-containing drugs have been withdrawn from market due to unforeseen toxicity issues. Other issues associated with the carboxylate moiety include reduced metabolic stability or limited passive diffusion across biological membranes. Medicinal chemists often turn to bioisosteres to circumvent such obstacles.

OBJECTIVE

The aim of this review is to provide a summary of the various applications of novel carboxylic acid bioisosteres which have appeared in the literature since 2013.

RESULTS

We have summarised the most recent developments in carboxylic acid bioisosterism. In particular, we focus on the changes in bioactivity, selectivity or physiochemical properties brought about by these substitutions, as well as the advantages and disadvantages of each isostere.

CONCLUSION

The topics discussed herein highlight the continued interest in carboxylate bioisosteres. The development of novel carboxylic acid substitutes which display improved pharmacological profiles is testament to the innovation and creativity required to overcome the challenges faced in modern drug design.

The Proteasome Inhibitor Bortezomib Induces Apoptosis and Activation in Gel-Filtered Human Platelets

Bortezomib (BTZ) has demonstrated its efficacy in several hematological disorders and has been associated with thrombocytopenia. There is controversy about the effect of BTZ on human platelets, so we set out to determine its effect on various types of platelet samples. Human platelets were investigated in platelet-rich plasma (PRP) and as gel-filtered platelets (GFPs). Mitochondrial inner membrane potential depolarization and phosphatidylserine (PS) and P-selectin expression levels were studied by flow cytometry, while thrombin generation was measured by a fluorescent method. In PRP, BTZ caused negligible PS expression after 60 min of treatment. However, in GFPs, PS expression was dose- and time-dependently increased in the BTZ-treated groups, as was P-selectin. The percentage of depolarized cells was also higher after BTZ pretreatment at both time points. Peak thrombin and velocity index increased significantly even with the lowest BTZ concentration (p = 0.0019; p = 0.0032) whereas time to peak and start tail parameters decreased (p = 0.0007; p = 0.0034). The difference between PRP and GFP results can be attributed to the presence of plasma proteins in PRP, as the PS-stimulating effect of BTZ could be attenuated by supplementing GFPs with purified human albumin. Overall, BTZ induces a procoagulant platelet phenotype in an experimental setting devoid of plasma proteins.

Small molecule inhibitors of the mitochondrial ClpXP protease possess cytostatic potential and re-sensitize chemo-resistant cancers

The human mitochondrial ClpXP protease complex (HsClpXP) has recently attracted major attention as a target for novel anti-cancer therapies. Despite its important role in disease progression, the cellular role of HsClpXP is poorly characterized and only few small molecule inhibitors have been reported. Herein, we screened previously established S. aureus ClpXP inhibitors against the related human protease complex and identified potent small molecules against human ClpXP. The hit compounds showed anti-cancer activity in a panoply of leukemia, liver and breast cancer cell lines. We found that the bacterial ClpXP inhibitor 334 impairs the electron transport chain (ETC), enhances the production of mitochondrial reactive oxygen species (mtROS) and thereby promotes protein carbonylation, aberrant proteostasis and apoptosis. In addition, 334 induces cell death in re-isolated patient-derived xenograft (PDX) leukemia cells, potentiates the effect of DNA-damaging cytostatics and re-sensitizes resistant cancers to chemotherapy in non-apoptotic doses.

Cleavage of HSP90β induced by histone deacetylase inhibitor and proteasome inhibitor modulates cell growth and apoptosis

HSP90, one of the molecular chaperones, contributes to protein stability in most living organisms. Previously, we found cleavage of HSP90 by caspase 10 in response to treatment with histone deacetylase inhibitor or proteasome inhibitor in leukemic cell lines. In this study, we investigated this phenomenon in various cell lines and found that HSP90 was cleaved by treatment with SAHA or MG132 in 6 out of 16 solid tumor cell lines. To further investigate the effects of HSP90 cleavage on cells, we introduced mutations to the potential cleavage sites of HSP90β and found that the 294th aspartic acid residue of the protein was mainly cleaved. In the K562 and Mia-PaCa-2 cell lines expressing HSP90β D294A, the cleavage of HSP90 by the treatment with SAHA or MG132 was reduced compared with the K562 and Mia-PaCa-2 cell lines expressing HSP90β WT. Accordingly, cell growth and survival were enhanced by HSP90β D294A expression. Therefore, we suggest that HSP90 cleavage widely occurs in several cell lines, and cleavage of HSP90 may have a potential for one of the mechanisms involved in the anti-tumor effects of known drugs and novel anti-tumor drug candidates.

Identification of an irreversible PPARγ antagonist with potent anticancer activity

Melanoma is responsible for most skin cancer deaths, and its incidence continues to rise year after year. Different treatment options have been developed for melanoma depending on the stage of the disease. Despite recent advances in immuno- and targeted therapies, advanced melanoma remains incurable and thus an urgent need persists for safe and more effective melanoma therapeutics. In this study, we demonstrate that a novel compound MM902 (3-(3-(bromomethyl)-5-(4-(tert-butyl) phenyl)-1H-1,2,4-triazol-1-yl) phenol) exhibited potent efficacies in inhibiting the growth of different cancer cells, and suppressed tumor growth in a mouse xenograft model of malignant melanoma. Beginning with MM902 instead of specific targets, computational similarity- and docking-based approaches were conducted to search for known anticancer drugs whose structural features match MM902 and whose pharmacological target would accommodate an irreversible inhibitor. Peroxisome proliferator-activated receptor (PPAR) was computationally identified as one of the pharmacological targets and confirmed by in vitro biochemical assays. MM902 was shown to bind to PPARγ in an irreversible mode of action and to function as a selective antagonist for PPARγ over PPARα and PPARδ. It is hoped that MM902 will serve as a valuable research probe to study the functions of PPARγ in tumorigenesis and other pathological processes.

From Cancer to Immune-Mediated Diseases and Tolerance Induction: Lessons Learned From Immune Oncology and Classical Anti-cancer Treatment

Success in cancer treatment over the last four decades has ranged from improvements in classical drug therapy to immune oncology. Anti-cancer drugs have also often proven beneficial for the treatment of inflammatory and autoimmune diseases. In this review, we report on challenging examples that bridge between treatment of cancer and immune-mediated diseases, addressing mechanisms and experimental models as well as clinical investigations. Patient-derived tumor xenograft (PDX) (humanized) mouse models represent useful tools for preclinical evaluation of new therapies and biomarker identification. However, new developments using human ex vivo approaches modeling cancer, for example in microfluidic human organs-on-chips, promise to identify key molecular, cellular and immunological features of human cancer progression in a fully human setting. Classical drugs which bridge the gap, for instance, include cytotoxic drugs, proteasome inhibitors, PI3K/mTOR inhibitors and metabolic inhibitors. Biologicals developed for cancer therapy have also shown efficacy in the treatment of autoimmune diseases. In immune oncology, redirected chimeric antigen receptor (CAR) T cells have achieved spectacular remissions in refractory B cell leukemia and lymphoma and are currently under development for tolerance induction using cell-based therapies such as CAR Tregs or NK cells. Finally, a brief outline will be given of the lessons learned from bridging cancer and autoimmune diseases as well as tolerance induction.

Effect Evaluation of Strychnos nux-vomica L. with Integrative Methods for Bortezomib-Induced Peripheral Neuropathy in Multiple Myeloma Patients: A Self-Controlled Clinical Trial

OBJECTIVE

To explore the clinical effect and adverse reactions of Strychnos nux-vomica in bortezomib-induced peripheral neuropathy (BIPN) of patients with multiple myeloma (MM).

METHODS

A total of 19 MM patients with BIPN were enrolled and Nux Vomica Capsule (NVC, 0.4 g, thrice daily) were orally administrated for 30 days. Comparative analysis on parameters between pre- and post-therapy, including peripheral neuropathy (PN) grade, neurotoxicity score, Chinese medicine (CM) syndrome score, total neuropathy score (TNS), coagulation function, and serum nerve growth factor (NGF) levels were conducted. The adverse events were monitored.

RESULTS

In BIPN of MM patients who received NVC, PN grade was lowered, neurotoxicity score was obviously decreased (P⩽0.01), and both CM syndrome score and TNS were remarkably decreased (P<0.01). After the therapy, activated partial thromboplastin time was prolonged (P<0.01) and fibrinogen was declined (P<0.05), showing improvement in the hypercoagulable state of patients. No significant difference of NGF recovery degrees was detected between pre- and post-therapy (P>0.05). No evident adverse reactions were observed during the course of treatment.

CONCLUSION

Strychnos nux-vomica L. has significantly effect with a good safety in treatment of BIPN in MM patients.

Modulation of stress and immune response by Amblyomin-X results in tumor cell death in a horse melanoma model

We have investigated Amblyomin-X-treated horse melanomas to better understand its mode of action through transcriptome analysis and the in vivo model. Amblyomin-X is a Kunitz-type homologous protein that selectively leads to the death of tumor cells via ER stress and apoptosis, currently under investigation as a new drug candidate for cancer treatment. Melanomas are immunogenic tumors, and a better understanding of the immune responses is warranted. Equine melanomas are spontaneous and not so aggressive as human melanomas are, as this study shows that the in vivo treatment of encapsulated horse melanoma tumors led to a significant reduction in the tumor size or even the complete disappearance of the tumor mass through intratumoral injections of Amblyomin-X. Transcriptome analysis identified ER- and mitochondria-stress, modulation of the innate immune system, apoptosis, and possibly immunogenic cell death activation. Interactome analysis showed that Amblyomin-X potentially interacts with key elements found in transcriptomics. Taken together, Amblyomin-X modulated the tumor immune microenvironment in different ways, at least contributing to induce tumor cell death.

Inhibition of microRNA-155 Reduces Neuropathic Pain During Chemotherapeutic Bortezomib via Engagement of Neuroinflammation

As a chemotherapeutic agent, bortezomib (BTZ) is used for the treatment of multiple myeloma with adverse effect of painful peripheral neuropathy. Our current study was to determine the inhibitory effects of blocking microRNA-155 (miR-155) signal on BTZ-induced neuropathic pain and the underlying mechanisms. We employed real time RT-PCR and western blot analysis to examine the miR-155 and expression of pro−inflammatory tumor necrosis factor-α receptor (TNFR1) in the dorsal horn of the spinal cord. Its downstream signals p38-MAPK and JNK and transient receptor potential ankyrin 1 (TRPA1) were also determined. Mechanical pain and cold sensitivity were assessed by behavioral test. In result, inhibition of miR-155 significantly attenuated mechanical allodynia and thermal hyperalgesia in BTZ rats, which was accompanied with decreasing expression of TNFR1, p38-MAPK, JNK, and TRPA1. In contrast, miRNA-155 mimics amplified TNFR1-TRPA1 pathway and augmented mechanical pain and cold sensitivity. In addition, mechanical and thermal hypersensitivity induced by miRNA-155 mimics were attenuated after blocking TNFR1, p38-MAPK, JNK, and TRPA1. Overall, we show the key role of miR-155 in modifying BTZ-induced neuropathic pain through TNFR1-TRPA1 pathway, suggesting that miR-155 is a potential target in preventing neuropathic pain development during intervention of BTZ.

Transition metal-free synthesis of alkyl pinacol boronates

This review systematically outlined the research in the area of transition metal free synthesis of alkyl pinacol boronates, which are versatile and important scaffolds to construct diverse organic compounds.

Chemotherapy-Induced Peripheral Neuropathy and Changes in Cytoskeleton

Despite the different antineoplastic mechanisms of action, peripheral neurotoxicity induced by all chemotherapy drugs (anti-tubulin agents, platinum compounds, proteasome inhibitors, thalidomide) is associated with neuron morphological changes ascribable to cytoskeleton modifications. The "dying back" degeneration of distal terminals (sensory nerves) of dorsal root ganglia sensory neurons, observed in animal models, in in vitro cultures and biopsies of patients is the most evident hallmark of the perturbation of the cytoskeleton. On the other hand, in highly polarized cells like neurons, the cytoskeleton carries out its role not only in axons but also has a fundamental role in dendrite plasticity and in the organization of soma. In the literature, there are many studies focused on the antineoplastic-induced alteration of microtubule organization (and consequently, fast axonal transport defects) while very few studies have investigated the effect of the different classes of drugs on microfilaments, intermediate filaments and associated proteins. Therefore, in this review, we will focus on: (1) Highlighting the fundamental role of the crosstalk among the three filamentous subsystems and (2) investigating pivotal cytoskeleton-associated proteins.

Bortezomib therapy in a real-world setting in patients with relapsed or refractory multiple myeloma

Bortezomib is a proteasome inhibitor, approved for treating newly diagnosed and relapsed multiple myeloma (MM). This realworld, multicenter, observational, non-interventional study of bortezomib was designed to collect and analyze prospective data in Taiwanese patients with relapsed or refractory MM. The primary endpoints included clinical effectiveness outcomes (disease response, disease progression [PD], time-to-response, time-toprogression, response duration, and overall survival [OS]). Secondary endpoints were safety and healthcare resource utilization.

Total 100 patients (median [range] age 64.9 [37.0-85.5] years) were enrolled; 47 patients completed the study. Of the withdrawn patients (n=53), there were 48 deaths (PD-related death: n=35, adverse events [AEs]-related: n=12, other reason: n=1), and 5 due to loss to follow-up. Four patients in Cycle 1, 6 patients each in Cycle 2 and 5, 7 in Cycle 3, 10 patients in Cycle 4, 5 patients in Cycle 6, and 3 patients each in Cycle 7 and 8 achieved overall response during the study. Time-to-response was 4.68 months (95%CI: 3.2, NE) and response duration was 10.08 months (95%CI: 2.3, 28.6). Median OS was 9.8 months (95%CI: 3.8, 13.7), and median time-to-progression was 11.3 months (95%CI: 6.2, 20.2). Most common non-hematological AEs were diarrhea (n=32) and hypoesthesia (n=25); most common hematological AE was thrombocytopenia (n=18).

Efficacy and safety profile of bortezomib in Taiwanese patients with MM was similar to global and other Asian population. Study provides a critical insight on use of bortezomib in realworld clinical practice, which can be helpful for Taiwanese healthcare providers’ decision-making processes.

Boronic acids as building blocks for the construction of therapeutically useful bioconjugates

This review summarizes boronic acid's contribution to the development of bioconjugates with a particular focus on the molecular mechanisms underlying its role in the construction and function of the bioconjugate, namely as a bioconjugation warhead, as a payload and as part of a bioconjugate linker.

Evaluating Treatment Strategies for Spinal Lesions in Multiple Myeloma: A Review of the Literature

Background

Vertebral disease is a major cause of morbidity in 70% of patients diagnosed with multiple myeloma (MM). Associated osteolytic lesions and vertebral fractures are well documented in causing debilitating pain, functional restrictions, spinal deformity, and cord compression. Currently, treatment modalities for refractory MM spinal pain include systemic therapy, radiotherapy, cementoplasty (vertebroplasty/kyphoplasty), and radio frequency ablation. Our objectives were to report on the efficacy of existing treatments for MM patients with refractory spinal pain, to determine if a standardized treatment algorithm has been described, and to set the foundation upon which future prospective studies can be designed.

Methods

A systematic search of the PubMed database was performed for studies relevant to the treatment of vertebral disease in MM patients. A multitude of search terms in various combinations were used, including but not limited to: "vertebroplasty," "kyphoplasty," "radiation," "multiple myeloma," "radiotherapy," and "radiosurgery."

Results

Our preliminary search resulted in 219 articles, which subsequently resulted in 19 papers following abstract, title, full-text, and bibliography review. These papers were then grouped by treatment modality: radiotherapy, cementoplasty, or combination therapy. Significant pain and functional score improvement across all treatment modalities was found in the majority of the literature. While complications of treatment occurred, few were noted to be clinically significant.

Conclusions

Treatment options-radiotherapy and/or cementoplasty-for vertebral lesions and pathologic fractures in MM patients demonstrate significant radiographic and clinical improvement. However, there is no consensus in the literature as to the optimal treatment modality as a result of a limited number of studies reporting head-to-head comparisons. One study did find significantly improved pain and functional scores with preserved vertebral height in favor of kyphoplasty over radiotherapy. When not contraindicated, we advocate for some form of cementoplasty. Further prospective studies are required before implementation of a standardized treatment protocol.

Level of Evidence

5.