Cancer is associated with higher morbidity and mortality and is the second leading cause of death in the US. Further, in some nations, cancer has overtaken heart disease as the leading cause of mortality. Identification of molecular mechanisms by which cancerous cells evade T cell-mediated cytotoxic damage has led to the modern era of immunotherapy in cancer treatment. Agents that release these immune brakes have shown activity to recover dysfunctional T cells and regress various cancer. Both cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and Programmed Death-1 (PD-1) play their role as physiologic brakes on unrestrained cytotoxic T effector function. CTLA-4 (CD 152) is a B7/CD28 family; it mediates immunosuppression by indirectly diminishing signaling through the co-stimulatory receptor CD28. Ipilimumab is the first and only FDA-approved CTLA-4 inhibitor; PD-1 is an inhibitory transmembrane protein expressed on T cells, B cells, Natural Killer cells (NKs), and Myeloid-Derived Suppressor Cells (MDSCs). Programmed Death-Ligand 1 (PD-L1) is expressed on the surface of multiple tissue types, including many tumor cells and hematopoietic cells. PD-L2 is more restricted to hematopoietic cells. Blockade of the PD-1 /PDL-1 pathway can enhance anti-tumor T cell reactivity and promotes immune control over the cancerous cells. Since the FDA approval of ipilimumab (human IgG1 k anti-CTLA-4 monoclonal antibody) in 2011, six more immune checkpoint inhibitors (ICIs) have been approved for cancer therapy. PD-1 inhibitors nivolumab, pembrolizumab, cemiplimab and PD-L1 inhibitors atezolizumab, avelumab, and durvalumab are in the current list of the approved agents in addition to ipilimumab. In this review paper, we discuss the role of each immune checkpoint inhibitor (ICI), the landmark trials which led to their FDA approval, and the strength of the evidence per National Comprehensive Cancer Network (NCCN), which is broadly utilized by medical oncologists and hematologists in their daily practice.

Guanine-quadruplexes (G4s) are non-canonical four-stranded structures that can be formed in guanine (G) rich nucleic acid sequences. A great number of G-rich sequences capable of forming G4 structures have been described based on in vitro analysis, and evidence supporting their formation in live cells continues to accumulate. While formation of DNA G4s (dG4s) within chromatin in vivo has been supported by different chemical, imaging and genomic approaches, formation of RNA G4s (rG4s) in vivo remains a matter of discussion. Recent data support the dynamic nature of G4 formation in the transcriptome. Such dynamic fluctuation of rG4 folding-unfolding underpins the biological significance of these structures in the regulation of RNA metabolism. Moreover, rG4-mediated functions may ultimately be connected to mechanisms underlying disease pathologies and, potentially, provide novel options for therapeutics. In this framework, we will review the landscape of rG4s within the transcriptome, focus on their potential impact on biological processes, and consider an emerging connection of these functions in human health and disease.

G-quadruplexes (GQs) are four-stranded secondary structures formed by G-rich nucleic acid sequence(s). DNA GQs are present abundantly in the genome and affect a wide range of processes associated with DNA. Recent studies show that RNA GQs are present in different transcripts, including coding and noncoding areas of mRNA, telomeric RNA as well as in other premature and mature noncoding RNAs. When present at specific locations within the RNAs, GQs play important roles in key biological functions, including the regulation of gene expression and telomere homeostasis. RNA GQs regulate pre-mRNA processing, such as splicing and polyadenylation. Evidently, among other processes, RNA GQs also control mRNA translation, miRNA and piRNA biogenesis, and RNA localization. The regulatory mechanisms controlled by RNA GQs mainly involve binding to RNA binding protein that modulate GQ conformation or serve as an entity in recruiting additional protein regulators to act as a block element to the processing machinery. Here we provide an overview of the ever-increasing number of discoveries revealing the role of RNA GQs in biology and their relevance in human diseases and therapeutics.

IMPORTANCEThe addition of daratumumab to backbone multiple myeloma (MM) regimens is associated with improved response rates and progression-free survival (PFS). Whether improved outcomes are also associated with this regimen among patients with cytogenetically defined high-risk MM (HRMM) remains unclear.OBJECTIVE To measure PFS associated with adding daratumumab to backbone MM regimens among patients with HRMM.DATA SOURCES For this systematic review and meta-analysis, MEDLINE, Embase, PubMed, Scopus, Web of Science Core Collection, Cochrane Library, clinical trials registries, and meeting libraries were searched from inception to January 2, 2020, using terms reflecting multiple myeloma and daratumumab.STUDY SELECTION Included studies were phase 3 randomized clinical trials that compared backbone MM regimens with the same regimen plus daratumumab in newly diagnosed or relapsed or refractory MM, such that the only difference between the intervention and control groups was use of daratumumab and reported outcomes by cytogenetic risk. High-risk MM was defined as the presence of t(4;14), t(14;16), or del(17p).DATA EXTRACTION AND SYNTHESIS Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, 2 investigators independently extracted study data, with disagreements resolved by a third investigator. Quality was assessed by the Cochrane risk-of-bias method.MAIN OUTCOMES AND MEASURES Data on effectiveness were extracted using hazard ratios (HRs) for PFS. Relative log-HRs were pooled using a DerSimonian-Laird random-effects model. Heterogeneity was assessed using the Cochran Q and the I 2 statistic. RESULTSOf 5194 studies screened, 6 phase 3 trials were eligible, including 3 trials for newly diagnosed MM (2528 patients; 358 with HRMM) and 3 trials for relapsed or refractory MM (1533 patients; 222 with HRMM). Among patients with newly diagnosed HRMM, the addition of daratumumab to backbone regimens was associated with improved PFS (pooled HR, 0.67; 95% CI, 0.47-0.95; P = .02), with little evidence of heterogeneity (Cochran Q, P = .77; I 2 = 0%). Similar results were seen among patients with relapsed or refractory HRMM (pooled HR, 0.45; 95% CI, 0.30-0.67; P < .001), again with little evidence of heterogeneity (Cochran Q, P = .63; I 2 = 0%).CONCLUSIONS AND RELEVANCE This study suggests that incorporating daratumumab to backbone regimens may be associated with improved PFS among patients with newly diagnosed HRMM or relapsed or refractory HRMM.

Although its mesomorphic properties have been studied for many years, only recently has the molecule of life begun to reveal the true range of its rich liquid crystalline behavior. End-to-end interactions between concentrated, ultrashort DNA duplexes—driving the self-assembly of aggregates that organize into liquid crystal phases—and the incorporation of flexible single-stranded “gaps” in otherwise fully paired duplexes—producing clear evidence of an elementary lamellar (smectic-A) phase in DNA solutions—are two exciting developments that have opened avenues for discovery. Here, we report on a wider investigation of the nature and temperature dependence of smectic ordering in concentrated solutions of various “gapped” DNA (GDNA) constructs. We examine symmetric GDNA constructs consisting of two 48-base pair duplex segments bridged by a single-stranded sequence of 2 to 20 thymine bases. Two distinct smectic layer structures are observed for DNA concentration in the range ∼230to∼280 mg/mL. One exhibits an interlayer periodicity comparable with two-duplex lengths (“bilayer” structure), and the other has a period similar to a single-duplex length (“monolayer” structure). The bilayer structure is observed for gap length ≳10 bases and melts into the cholesteric phase at a temperature between 30 °C and 35 °C. The monolayer structure predominates for gap length ≲10 bases and persists to >40 °C. We discuss models for the two layer structures and mechanisms for their stability. We also report results for asymmetric gapped constructs and for constructs with terminal overhangs, which further support the model layer structures.

Highlights d INCR1 is expressed from the PD-L1 locus in interferonstimulated tumor cells d INCR1 regulates tumor interferon signaling d Silencing INCR1 sensitizes tumor cells to T cell-mediated killing d INCR1 binds HNRNPH1 to promote PD-L1 and JAK2 expression

As cells encounter adverse environmental conditions, such as hypoxia, oxidative stress or nutrient deprivation, they trigger stress response pathways to protect themselves until transient stresses have passed. Inhibition of translation is a key component of such cellular stress responses and mounting evidence has revealed the importance of a class of tRNA-derived small RNAs called tiRNAs in this process. The most potent of these small RNAs are those with the capability of assembling into tetrameric G-quadruplex (G4) structures. However, the mechanism by which these small RNAs inhibit translation has yet to be elucidated. Here we show that eIF4G, the major scaffolding protein in the translation initiation complex, directly binds G4s and this activity is required for tiRNA-mediated translation repression. Targeting of eIF4G results in an impairment of 40S ribosome scanning on mRNAs leading to the formation of eIF2α-independent stress granules. Our data reveals the mechanism by which tiRNAs inhibit translation and demonstrates novel activity for eIF4G in the regulation of translation.

Recent transcriptome-wide studies have identified a diverse pool of transfer RNA (tRNA)derived RNAs or tRNA-derived fragments (tRFs). Some of these RNAs have been demonstrated to be functional and involved in multiple biological processes ranging from the regulation of gene expression to transgenerational epigenetic inheritance. Post-transcriptional maturation of tRNAs includes various processing events including extensive decoration by various RNA modifications, which are required for correct tRNA folding and stability. Moreover, tRNA modifications determine the pattern and specificity of tRNA cleavage. The major drawbacks of many studies in the field of tRFs are that most of them used synthetic RNAs that closely mimic endogenous tRFs in their sequence, yet lack RNA modification that is found in vivo. Here, we developed a simple method to isolate tRNA-derived stress-induced RNAs (tiRNAs), a specific subset of tRFs. Our approach is scalable, cost-effective and relies on the purification of individual tiRNAs based on a sequence-specific RNA/DNA isolation technique using DNA probes. Our method facilitates functional studies of tiRNAs by addressing how physiological RNA modifications within tRNA fragments affect their biological activities. Here, we report pilot functional studies on selected endogenous tiRNAs, namely tiRNA Ala and tiRNA Gly . We show that natural 5ʹ-tiRNA Ala molecules assemble into G-quadruplex structures, and endogenous 5ʹ-tiRNA Gly possesses translation inhibition activity.