Trastuzumab deruxtecan in patients with solid tumours harbouring specific activating HER2 mutations (DESTINY-PanTumor01): an international, phase 2 study.

BACKGROUND: Trastuzumab deruxtecan is a HER2-directed antibody-drug conjugate approved by the US Food and Drug Administration and the European Medicines Agency for HER2-mutant non-small-cell lung cancer. Few treatment options exist for patients with HER2-mutant solid tumours beyond lung cancers. We investigated trastuzumab deruxtecan in metastatic solid tumours with specific activating HER2 mutations. METHODS: In this open-label, phase 2, basket study done in 29 centres in Asia, Europe, and North America, we investigated trastuzumab deruxtecan (5·4 mg/kg every 3 weeks by intravenous infusion) in patients aged 18 years or older with unresectable or metastatic solid tumours with specific activating HER2 mutations, an Eastern Cooperative Oncology Group performance status of 0 or 1, and disease progression following previous treatment (previous HER2-targeted therapy was permitted) or with no satisfactory alternative treatment options. The primary endpoint was confirmed objective response rate by independent central review. Anti-tumour activity and safety were analysed in all patients who received at least one dose of trastuzumab deruxtecan. This trial is registered with ClinicalTrials.gov, NCT04639219, and is active but no longer recruiting. FINDINGS: Between Dec 30, 2020, and Jan 25, 2023, 102 patients (62 [61%] female and 40 [39%] male; median age 66·5 years [IQR 58-72]; 51 [50%] White, two [2%] Black or African American, 38 [37%] Asian, and 11 [11%] did not have race information reported) with solid tumours with activating HER2 mutations received trastuzumab deruxtecan and were included in the anti-tumour activity and safety analyses sets. Patients had a median of three (IQR 2-4) previous treatment regimens. The median duration of follow-up was 8·61 months (IQR 3·71-12·68). The objective response rate by independent central review was 29·4% (95% CI 20·8-39·3; 30 of 102 patients). 52 (51%) patients had a treatment-emergent adverse event of grade 3 or worse; the most common events (in ≥5% of patients) were anaemia (16 [16%]) and neutrophil count decreased (eight [8%]). Drug-related treatment-emergent serious adverse events occurred in ten (10%) patients. Adjudicated drug-related interstitial lung disease or pneumonitis of any grade occurred in 11 patients (11%; three grade 1, five grade 2, one grade 3, and two grade 5); there were two (2%) cases of fatal adjudicated drug-related interstitial lung disease or pneumonitis. INTERPRETATION: Trastuzumab deruxtecan showed anti-tumour activity and durable responses in heavily pretreated patients across multiple tumour types with activating HER2 mutations, with no new safety signals. Prespecified HER2 mutations might be targeted by HER2-directed antibody-drug conjugates and our findings support further investigation of trastuzumab deruxtecan in the pan-tumour setting. FUNDING: AstraZeneca and Daiichi Sankyo.

Homogenized and Lyophilized Amniotic Membrane Dressings for the Treatment of Diabetic Foot Ulcers in Ambulatory Patients.

BACKGROUND: Diabetic foot ulcers (DFUs) constitute a complication that occurs in 19% to 34% of patients with diabetes mellitus (DM). The aim of this study is to describe median days to healing, average velocity of wound closure, and percentage of wound surface closed at 3, 6, and 12 weeks through the use of homogenized and lyophilized amniotic membrane (hAMpe) dressings for the treatment of DFUs in ambulatory patients. METHODS: An observational, descriptive, longitudinal study was performed. Patients presenting with granulation-based DFU, after proper debridement, were included from August 19, 2021, until July 14, 2023. hAMpe dressings placed every 3 days were used for the treatment of these ulcers. RESULTS: Sixteen patients were included with a mean age of 52.38 (8.07) years. The analyzed lesions were postsurgical ulcers in 15 of the 16 included patients. Median ulcer size was 19.5 cm2 (6.12-36). The median ABI was 1.10 (1-1.14). The median days to healing was 96 (71-170). The median percentage closure of the wound at 3 weeks was 41% (28.9%-55.3%), at 6 weeks it was 68.2% (48.6%-74.2%), and at 12 weeks it was 100% (81%-100%). The average velocity closure was 1.04% per day (95% CI 0.71%-1.31%). It was higher during the closure of the first 50% of the ulcer, 2.12% per day (95% CI 0.16%-4.09%), and decreased from 50% to 25% of the ulcer size to 0.67% per day (95% CI 0.23%-1.10%) and from 25% to closure to 0.47% per day (95% CI 0.14%-0.80%), P < .001. CONCLUSION: These results are difficult to compare to other studies given the higher surface area of the ulcers included in our sample. The development of hAMpe dressings enables patients to apply them without requiring assistance from health care teams and was not associated with any recognized complications. LEVEL OF EVIDENCE: Level IV, case series.

Two synthetic steroid analogs reduce human respiratory syncytial virus replication and the immune response to infection both in vitro and in vivo.

HRSV is responsible for many acute lower airway infections and hospitalizations in infants, the elderly and those with weakened immune systems around the world. The strong inflammatory response that mediates viral clearance contributes to pathogenesis, and is positively correlated with disease severity. There is no specific effective therapy on hand. Antiviral synthetic stigmastanes (22S, 23S)-22,23-dihydroxystigmast-4-en-3-one (Compound 1) and 22,23-dihydroxystigmasta-1,4-dien-3-one (Compound 2) have shown to be active inhibiting unrelated virus like Herpes Simplex type 1 virus (HSV-1) and Adenovirus, without cytotoxicity. We have also shown that Compound 1 modulates the activation of cell signaling pathways and cytokine secretion in infected epithelial cells as well as in inflammatory cells activated by nonviral stimuli. In the present work, we investigated the inhibitory effect of both compounds on HRSV replication and their modulatory effect on infected epithelial and inflammatory cells. We show that compounds 1 and 2 inhibit in vitro HRSV replication and propagation and reduce cytokine secretion triggered by HRSV infection in epithelial and inflammatory cells. The compounds reduce viral loads and inflammatory infiltration in the lungs of mice infected with HRSV.

The Oncogenic PI3K-Induced Transcriptomic Landscape Reveals Key Functions in Splicing and Gene Expression Regulation.

The phosphoinositide 3-kinase (PI3K) pathway regulates proliferation, survival, and metabolism and is frequently activated across human cancers. A comprehensive elucidation of how this signaling pathway controls transcriptional and cotranscriptional processes could provide new insights into the key functions of PI3K signaling in cancer. Here, we undertook a transcriptomic approach to investigate genome-wide gene expression and transcription factor activity changes, as well as splicing and isoform usage dynamics, downstream of PI3K. These analyses uncovered widespread alternatively spliced isoforms linked to proliferation, metabolism, and splicing in PIK3CA-mutant cells, which were reversed by inhibition of PI3Kα. Analysis of paired tumor biopsies from patients with PIK3CA-mutated breast cancer undergoing treatment with PI3Kα inhibitors identified widespread splicing alterations that affect specific isoforms in common with the preclinical models, and these alterations, namely PTK2/FRNK and AFMID isoforms, were validated as functional drivers of cancer cell growth or migration. Mechanistically, isoform-specific splicing factors mediated PI3K-dependent RNA splicing. Treatment with splicing inhibitors rendered breast cancer cells more sensitive to the PI3Kα inhibitor alpelisib, resulting in greater growth inhibition than alpelisib alone. This study provides the first comprehensive analysis of widespread splicing alterations driven by oncogenic PI3K in breast cancer. The atlas of PI3K-mediated splicing programs establishes a key role for the PI3K pathway in regulating splicing, opening new avenues for exploiting PI3K signaling as a therapeutic vulnerability in breast cancer. SIGNIFICANCE: Transcriptomic analysis reveals a key role for the PI3K pathway in regulating RNA splicing, uncovering new mechanisms by which PI3K regulates proliferation and metabolism in breast cancer. See related commentary by Claridge and Hopkins, p. 2216.

Bystander effect of antibody-drug conjugates: fact or fiction?

PURPOSE OF REVIEW: Summarizing the current preclinical and clinical evidence about bystander effect of antibody-drug conjugates (ADCs) in solid tumors. RECENT FINDINGS: One of the main challenges of treating solid tumors with ADCs is the heterogeneous expression of the target antigen (Ag), which however may be overcome by the so-called bystander killing effect. This unique, but still debated, feature of certain ADCs is represented by the unintentional payload diffusion from Ag-positive tumor cells to adjacent Ag-negative tumor cells. Some pharmacological characteristics, such as a hydrophobic payload or a cleavable linker, seem to play a major role in this effect. Abundant preclinical evidence of the bystander effect has emerged, and the clinical activity of ADCs in tumors with a heterogeneous Ag expression suggests the relevance of this feature. Additional studies are required to investigate if the bystander effect is necessary for achieving a solid activity with ADCs.

Genomic Alterations in PIK3CA-Mutated Breast Cancer Result in mTORC1 Activation and Limit the Sensitivity to PI3Kα Inhibitors.

PI3Kα inhibitors have shown clinical activity in PIK3CA-mutated estrogen receptor-positive (ER+) patients with breast cancer. Using whole genome CRISPR/Cas9 sgRNA knockout screens, we identified and validated several negative regulators of mTORC1 whose loss confers resistance to PI3Kα inhibition. Among the top candidates were TSC1, TSC2, TBC1D7, AKT1S1, STK11, MARK2, PDE7A, DEPDC5, NPRL2, NPRL3, C12orf66, SZT2, and ITFG2. Loss of these genes invariably results in sustained mTOR signaling under pharmacologic inhibition of the PI3K-AKT pathway. Moreover, resistance could be prevented or overcome by mTOR inhibition, confirming the causative role of sustained mTOR activity in limiting the sensitivity to PI3Kα inhibition. Cumulatively, genomic alterations affecting these genes are identified in about 15% of PIK3CA-mutated breast tumors and appear to be mutually exclusive. This study improves our understanding of the role of mTOR signaling restoration in leading to resistance to PI3Kα inhibition and proposes therapeutic strategies to prevent or revert this resistance. SIGNIFICANCE: These findings show that genetic lesions of multiple negative regulators of mTORC1 could limit the efficacy of PI3Kα inhibitors in breast cancer, which may guide patient selection strategies for future clinical trials.

MRE11-RAD50-NBS1 Complex Is Sufficient to Promote Transcription by RNA Polymerase II at Double-Strand Breaks by Melting DNA Ends.

The MRE11-RAD50-NBS1 (MRN) complex supports the synthesis of damage-induced long non-coding RNA (dilncRNA) by RNA polymerase II (RNAPII) from DNA double-strand breaks (DSBs) by an unknown mechanism. Here, we show that recombinant human MRN and native RNAPII are sufficient to reconstitute a minimal functional transcriptional apparatus at DSBs. MRN recruits and stabilizes RNAPII at DSBs. Unexpectedly, transcription is promoted independently from MRN nuclease activities. Rather, transcription depends on the ability of MRN to melt DNA ends, as shown by the use of MRN mutants and specific allosteric inhibitors. Single-molecule FRET assays with wild-type and mutant MRN show a tight correlation between the ability to melt DNA ends and to promote transcription. The addition of RPA enhances MRN-mediated transcription, and unpaired DNA ends allow MRN-independent transcription by RNAPII. These results support a model in which MRN generates single-strand DNA ends that favor the initiation of transcription by RNAPII.

A synthetic stigmastane displays antiadenoviral activity and reduces the inflammatory response to viral infection.

Although human adenovirus (ADV) infections are mild and self-limited in immunocompetent individuals, they can be severe and life-threatening in immunocompromised patients. Despite their significant clinical impact, there are not currently approved antiviral therapies for ADV infections. On the other hand, in some cases, the immune response induced by ADV infection can cause tissue damage. Even more, in the case of adenovirus vectors used in gene therapy, host immunity generally antagonize viral efficacy. Therefore, the need for searching an effective and safe therapy is increasing. In this work, we describe the antiadenoviral activity of the synthetic stigmastane (22S, 23S)-22,23-dihydroxystigmast-4-en-3-one (Compound 1) with already reported antiviral and antiinflammatory activities against other viruses of clinical importance. Compound 1 displayed no virucidal activity and did not affect ADV entry to the cells. The compound inhibited viral replication and it also reduced cytokine secretion in epithelial and inflammatory infected cells. Thus, Compound 1 would be a promissory drug potentially useful against adenoviral infections as well as an adjuvant of adenoviral vectors in gene therapy.

HER2-Mediated Internalization of Cytotoxic Agents in ERBB2 Amplified or Mutant Lung Cancers.

Amplification of and oncogenic mutations in ERBB2, the gene encoding the HER2 receptor tyrosine kinase, promote receptor hyperactivation and tumor growth. Here we demonstrate that HER2 ubiquitination and internalization, rather than its overexpression, are key mechanisms underlying endocytosis and consequent efficacy of the anti-HER2 antibody-drug conjugates (ADC) ado-trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) in lung cancer cell lines and patient-derived xenograft models. These data translated into a 51% response rate in a clinical trial of T-DM1 in 49 patients with ERBB2-amplified or -mutant lung cancers. We show that cotreatment with irreversible pan-HER inhibitors enhances receptor ubiquitination and consequent ADC internalization and efficacy. We also demonstrate that ADC switching to T-DXd, which harbors a different cytotoxic payload, achieves durable responses in a patient with lung cancer and corresponding xenograft model developing resistance to T-DM1. Our findings may help guide future clinical trials and expand the field of ADC as cancer therapy. SIGNIFICANCE: T-DM1 is clinically effective in lung cancers with amplification of or mutations in ERBB2. This activity is enhanced by cotreatment with irreversible pan-HER inhibitors, or ADC switching to T-DXd. These results may help address unmet needs of patients with HER2-activated tumors and no approved targeted therapy.See related commentary by Rolfo and Russo, p. 643.This article is highlighted in the In This Issue feature, p. 627.

RNase A treatment and reconstitution with DNA damage response RNA in living cells as a tool to study the role of non-coding RNA in the formation of DNA damage response foci.

Non-coding RNA (ncRNA) molecules have been shown to play a variety of cellular roles; however, the contributions of different types of RNA to specific phenomena are often hard to dissect. To study the role of RNA in the assembly of DNA damage response (DDR) foci, we developed the RNase A treatment and reconstitution (RATaR) method, in which cells are mildly permeabilized, incubated with recombinant RNase A and subsequently reconstituted with different RNA species, under conditions of RNase A inactivation and inhibition of endogenous transcription. The block of transcription right after RNase A removal represents a key innovation of RATaR, preventing potential contributions of endogenously neo-synthesized transcripts to the phenotypes studied. A critical aspect of this technique is the balance between sufficient permeabilization of membranes to allow enzyme/RNA access into the cell nucleus and cell viability. Here, we present our protocol for RNA-dependent DDR foci disassembly and reassembly using fluorescent DDR RNAs (DDRNAs) in NIH2/4 cells, an engineered NIH3T3-derived cell line. The use of sequence-specific, fluorescent RNA molecules permits the concomitant determination of their subcellular localization and biological functions. We also outline adaptations of RATaR when implemented in different cell lines exposed to various genotoxic treatments, such as γ-radiation, restriction enzymes and telomere deprotection. In all these cases, the entire procedure can be completed within 2 h without the need for special equipment or uncommon skills. We believe this technique will prove useful for investigating the contribution of RNA to a variety of relevant cellular processes.

Pharmacological boost of DNA damage response and repair by enhanced biogenesis of DNA damage response RNAs.

A novel class of small non-coding RNAs called DNA damage response RNAs (DDRNAs) generated at DNA double-strand breaks (DSBs) in a DROSHA- and DICER-dependent manner has been shown to regulate the DNA damage response (DDR). Similar molecules were also reported to guide DNA repair. Here, we show that DDR activation and DNA repair can be pharmacologically boosted by acting on such non-coding RNAs. Cells treated with enoxacin, a compound previously demonstrated to augment DICER activity, show stronger DDR signalling and faster DNA repair upon exposure to ionizing radiations compared to vehicle-only treated cells. Enoxacin stimulates DDRNA production at chromosomal DSBs and at dysfunctional telomeres, which in turn promotes 53BP1 accumulation at damaged sites, therefore in a miRNA-independent manner. Increased 53BP1 occupancy at DNA lesions induced by enoxacin ultimately suppresses homologous recombination, channelling DNA repair towards faster and more accurate non-homologous end-joining, including in post-mitotic primary neurons. Notably, augmented DNA repair stimulated by enoxacin increases the survival also of cancer cells treated with chemotherapeutic agents.

Aesculus hippocastanum L. seed extract shows virucidal and antiviral activities against respiratory syncytial virus (RSV) and reduces lung inflammation in vivo.

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease and bronchiolitis in children worldwide. No vaccine or specific, effective treatment is currently available. ß-escin is one of the main bioactive constituents of Aesculus hippocastanum L. (Hippocastanaceae) seed extract (AH), and both ß-escin and AH have demonstrated a beneficial role in clinical therapy because of their anti-edematous, anti-inflammatory and antioxidative effects. Besides, we have reported that ß-escin and AH show virucidal, antiviral and immunomodulatory activities against the enveloped viruses HSV-1, VSV and Dengue virus in vitro. In this study, we demonstrate that ß-escin and AH have virucidal and antiviral activities against RSV, as well as NF-κB, AP-1 and cytokine modulating activities in RSV infected epithelial and macrophage cell lines in vitro. Besides, in a murine model of pulmonary RSV infection, AH treatment improves the course of acute disease, evidenced by decreased weight loss, reduced RSV lung titers, and attenuated airway inflammation. In contrast, even though ß-escin showed, similarly to AH, antiviral and immunomodulatory properties in vitro, it neither reduces viral titers nor attenuates lung injury in vivo. Thus, our data demonstrate that AH restrains RSV disease through antiviral and immunomodulatory effect.

Virucidal, antiviral and immunomodulatory activities of ß-escin and Aesculus hippocastanum extract.

OBJECTIVES: ß-Escin, one of the constituents of Aesculus hippocastanum L. (Hippocastanaceae) seed extract (AH), inhibits NF-κB activation, which plays an important role in HSV-1 replication. The aim was to examine the antiherpetic activity of ß-escin and AH, as well as their effect on the activation of NF-κB and AP-1 and cytokine secretion in epithelial cells and macrophages. METHODS: Cell viability was evaluated using MTT assay, and antiviral and virucidal activity was determined by plaque assay. The effect on NF-κB and AP-1 signalling pathways activation was determined by a luciferase reporter assay, and cytokine production was measured by ELISA. KEY FINDINGS: ß-Escin and AH had virucidal and anti-HSV-1 activities, and the antiviral activity was discovered for other enveloped viruses (VSV and Dengue). Moreover, ß-escin and AH significantly reduced NF-κB and AP-1 activation and cytokine production in macrophages stimulated with HSV-1 and TLRs ligands. However, an enhanced activation of these pathways and an increase in the levels of pro-inflammatory cytokines in ß-escin and AH-treated HSV-1-infected epithelial cells were found. CONCLUSIONS: This study demonstrates virucidal and broad-spectrum antiviral activities for ß escin and AH. Besides, ß-escin and AH modulate cytokine production depending on the stimuli (viral or non-viral) and the cell type under study.

From "Cellular" RNA to "Smart" RNA: Multiple Roles of RNA in Genome Stability and Beyond.

Coding for proteins has been considered the main function of RNA since the "central dogma" of biology was proposed. The discovery of noncoding transcripts shed light on additional roles of RNA, ranging from the support of polypeptide synthesis, to the assembly of subnuclear structures, to gene expression modulation. Cellular RNA has therefore been recognized as a central player in often unanticipated biological processes, including genomic stability. This ever-expanding list of functions inspired us to think of RNA as a "smart" phone, which has replaced the older obsolete "cellular" phone. In this review, we summarize the last two decades of advances in research on the interface between RNA biology and genome stability. We start with an account of the emergence of noncoding RNA, and then we discuss the involvement of RNA in DNA damage signaling and repair, telomere maintenance, and genomic rearrangements. We continue with the depiction of single-molecule RNA detection techniques, and we conclude by illustrating the possibilities of RNA modulation in hopes of creating or improving new therapies. The widespread biological functions of RNA have made this molecule a reoccurring theme in basic and translational research, warranting it the transcendence from classically studied "cellular" RNA to "smart" RNA.

Damage-induced lncRNAs control the DNA damage response through interaction with DDRNAs at individual double-strand breaks.

The DNA damage response (DDR) preserves genomic integrity. Small non-coding RNAs termed DDRNAs are generated at DNA double-strand breaks (DSBs) and are critical for DDR activation. Here we show that active DDRNAs specifically localize to their damaged homologous genomic sites in a transcription-dependent manner. Following DNA damage, RNA polymerase II (RNAPII) binds to the MRE11-RAD50-NBS1 complex, is recruited to DSBs and synthesizes damage-induced long non-coding RNAs (dilncRNAs) from and towards DNA ends. DilncRNAs act both as DDRNA precursors and by recruiting DDRNAs through RNA-RNA pairing. Together, dilncRNAs and DDRNAs fuel DDR focus formation and associate with 53BP1. Accordingly, inhibition of RNAPII prevents DDRNA recruitment, DDR activation and DNA repair. Antisense oligonucleotides matching dilncRNAs and DDRNAs impair site-specific DDR focus formation and DNA repair. We propose that DDR signalling sites, in addition to sharing a common pool of proteins, individually host a unique set of site-specific RNAs necessary for DDR activation.

A damaged genome's transcriptional landscape through multilayered expression profiling around in situ-mapped DNA double-strand breaks.

Of the many types of DNA damage, DNA double-strand breaks (DSBs) are probably the most deleterious. Mounting evidence points to an intricate relationship between DSBs and transcription. A cell system in which the impact on transcription can be investigated at precisely mapped genomic DSBs is essential to study this relationship. Here in a human cell line, we map genome-wide and at high resolution the DSBs induced by a restriction enzyme, and we characterize their impact on gene expression by four independent approaches by monitoring steady-state RNA levels, rates of RNA synthesis, transcription initiation and RNA polymerase II elongation. We consistently observe transcriptional repression in proximity to DSBs. Downregulation of transcription depends on ATM kinase activity and on the distance from the DSB. Our study couples for the first time, to the best of our knowledge, high-resolution mapping of DSBs with multilayered transcriptomics to dissect the events shaping gene expression after DSB induction at multiple endogenous sites.

Synthetic stigmasterol derivatives inhibit capillary tube formation, herpetic corneal neovascularization and tumor induced angiogenesis: Antiangiogenic stigmasterol derivatives.

Angiogenesis plays a critical role in initiating and promoting several diseases, such as cancer and herpetic stromal keratitis (HSK). Herein, we studied the inhibitory effect of two synthetic stigmasterol derivatives on capillary tube-like structures and on cell migration in human umbilical vein endothelial cells (HUVEC): (22S,23S)-22,23-dihydroxystigmast-4-en-3-one (compound 1) and (22S,23S)-3ß-bromo-5α,22,23-trihydroxystigmastan-6-one (compound 2). We also studied their effect on VEGF expression in IL-6 stimulated macrophages and in LMM3 breast cancer cells. Furthermore, we investigated the antiangiogenic activity of the compounds on corneal neovascularization in the murine model of HSK and in an experimental model of tumor-induced angiogenesis in mice. Both compounds inhibited capillary tube-like formation, but only compound 1 restrained cell migration. Compound 1, unlike compound 2, was able to reduce VEGF expression. Only compound 1 not only reduced the incidence and severity of corneal neovascularization, when administered at the onset of HSK, but it also restrained the development of neovascular response induced by tumor cells in mice skin. Our results show that compound 1 inhibits angiogenesis in vitro and in vivo. Therefore, compound 1 would be a promising drug in the treatment of those diseases where angiogenesis represents one of the main pathogenic events.

Synthetic stigmastanes with dual antiherpetic and immunomodulating activities inhibit ERK and Akt signaling pathways without binding to glucocorticoid receptors.

BACKGROUND: We have previously shown that some synthetic hydroxylated stigmastanes derived from plant sterols inhibit in vitro HSV-1 replication in ocular cell lines and decrease cytokine production in stimulated macrophages, suggesting that these steroids might combine antiviral and immunomodulating properties. In this paper we report the synthesis of some analogs fluorinated at C-6 in order to study the effect of this modification on bioactivity. METHODS: The following methods were used: organic synthesis of fluorinated analogs, cytotoxicity determination with MTT assays, cytokine production quantification with ELISAs, glucocorticoid activity determination by displacement assays, immunofluorescence and transcriptional activity assays, studies of the activation of signaling pathways by Western blot, antiviral activity evaluation through virus yield reduction assays. RESULTS: We report the chemical synthesis of new fluorinated stigmastanes and show that this family of steroidal compounds exerts its immunomodulating activity by inhibiting ERK and Akt signaling pathways, but do not act as glucocorticoids. We also demonstrate that fluorination enhances the antiviral activity. CONCLUSIONS: Fluorination on C-6 did not enhance the anti-inflammatory effect, however, an increase in the in vitro antiviral activity was observed. Thus, our results suggest that it is possible to introduce chemical modifications on the parent steroids in order to selectively modulate one of the effects. GENERAL SIGNIFICANCE: This family of steroids could allow the development of an alternative treatment for ocular immunopathologies triggered by HSV-1, without the undesirable side effects of the currently used drugs.

Small Molecules as Anti-TNF Drugs.

Tumor necrosis factor (TNF, TNF-α, cachectin) is a pleiotropic, proinflammatory cytokine with multiple biological effects, many of which are not yet fully understood. Although TNF was initially described as an anti-tumor agent more than three decades ago, current knowledge places it central to immune system homeostasis. TNF plays a critical role in host defense against infection, as well as an inhibitory role in autoimmune disease. However, TNF overproduction generates deleterious effects by inducing the transcription of genes involved in acute and chronic inflammatory responses including asthma, rheumatoid arthritis, Crohn's disease, and psoriasis. Direct inhibition of TNF by biologics, such as monoclonal antibodies and circulating TNF receptor constructs, has produced effective treatments for these disorders and validated the inhibition of this proinflammatory cytokine as an effective therapy. Unfortunately, these biological therapies suffer from several drawbacks, including high cost and the induction of autoantibody production. Thus, the development of small molecules able to modulate TNF production or signaling pathways remains a central challenge in Medicinal Chemistry. Considerable efforts have been made over the past two decades to develop such inhibitors, which could potentially be administered orally and would presumably be cheaper. This review is focused on the recent development of compounds that modulate the activity of this cytokine by acting at different levels, such as TNF expression, processing, binding to its receptors and direct inhibition. These approaches will be compared and discussed.