Serologic Response to Vaccine for COVID-19 in Patients with Hematologic Malignancy: A Prospective Cohort Study.

BACKGROUND: Patients with hematological cancers have increased COVID-19 morbidity and mortality, and these patients show attenuated vaccine responses. This study aimed to characterize the longitudinal humoral immune responses to COVID-19 vaccination in patients with hematological malignancies. PATIENTS AND METHODS: We conducted a prospective cohort study, collecting samples from March 2021 to July 2022, from patients seen at a cancer treatment center in London, Ontario, Canada, who met the following eligibility criteria: age ≥18 years, diagnosed with a hematological malignancy, recipient of a COVID-19 vaccine during the study period, and able to provide informed consent. RESULTS: Median anti-S titers (MST) were 0.0, 64.0, and 680.5 U/mL following first (V1), second (V2), and third (V3) vaccine doses, respectively. Patients with lymphoid malignancies' response to vaccination was attenuated compared to myeloid malignancy patients after V2 and V3 (P < .001, P < .01). Active treatment was associated with lower antibody titers (MST 10) compared to treatment 12-24 months (MST 465, P = .04367) and >24 months (MST 1660.5, P = .0025) prior to vaccination. V3 significantly increased antibody titers compared to V2 for patients less than 3 months from treatment. Increasing age was associated with smaller antibody response following V2 (P < .05), but not following V3. Patients receiving anti-CD20 therapy did not demonstrate increased antibody titer levels after V3 (V2 MST 0, V3 MST 0; P > .05). CONCLUSION: We report an attenuated serologic response to COVID-19 vaccination in our study population of patients with hematological malignancy. The immune response to vaccination was affected by patient age, diagnosis, treatment, and timing of treatment exposure.

A Rare Association of Mixed Autoimmune Hemolytic Anemia with Gastric Carcinoma.

This case report outlines a 70-year-old female patient who presented with a concurrent mixed autoimmune hemolytic anemia (AIHA) and a gastric adenocarcinoma. Her treatment course of these two diseases is summarized, which included supportive care, neoadjuvant chemotherapy for her gastric adenocarcinoma, steroids, rituximab, and surgical resection of the tumor. This approach ultimately led to the stabilization of her AIHA and primary cure for her solid malignancy. We briefly review both AIHA and gastric adenocarcinoma as clinical entities, propose working causes of hemolytic anemia including gastric adenocarcinoma, and outline a successful treatment pathway for these two concurrent conditions.

Apoptotic Blocks in Primary Non-Hodgkin B Cell Lymphomas Identified by BH3 Profiling.

To determine causes of apoptotic resistance, we analyzed 124 primary B cell NHL samples using BH3 profiling, a technique that measures the mitochondrial permeabilization upon exposure to synthetic BH3 peptides. Our cohort included samples from chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), high-grade B cell lymphoma with translocations in MYC and BCL2 (HGBL-DH), mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL). While a large number of our samples displayed appropriate responses to apoptosis-inducing peptides, pro-apoptotic functional defects, implicating BAX, BAK, BIM or BID, were seen in 32.4% of high-grade NHLs (12/37) and in 3.4% of low-grade NHLs (3/87, p < 0.0001). The inhibition of single anti-apoptotic proteins induced apoptosis in only a few samples, however, the dual inhibition of BCL2 and MCL1 was effective in 83% of samples, indicating MCL1 was the most common cause of lack of response to the BCL2 inhibitor, venetoclax. We then profiled Toledo and OCI-Ly8 high-grade lymphoma cell lines to determine which drugs could reduce MCL1 expression and potentiate venetoclax responses. Doxorubicin and vincristine decreased levels of MCL1 and increased venetoclax-induced apoptosis (all p < 0.05). Overall, in primary NHLs expressing BCL2 that have no defects in pro-apoptotic signaling, a poor response to venetoclax is primarily due to the presence of MCL1, which may be overcome by combining venetoclax with doxorubicin and vincristine-based chemotherapy or with other anti-microtubule inhibitors.

Piperazin-1-ylpyridazine Derivatives Are a Novel Class of Human dCTP Pyrophosphatase 1 Inhibitors.

The dCTP pyrophosphatase 1 (dCTPase) is a nucleotide pool "housekeeping" enzyme responsible for the catabolism of canonical and noncanonical nucleoside triphosphates (dNTPs) and has been associated with cancer progression and cancer cell stemness. We have identified a series of piperazin-1-ylpyridazines as a new class of potent dCTPase inhibitors. Lead compounds increase dCTPase thermal and protease stability, display outstanding selectivity over related enzymes and synergize with a cytidine analogue against leukemic cells. This new class of dCTPase inhibitors lays the first stone toward the development of drug-like probes for the dCTPase enzyme.

Lysophosphatidic acid receptor (LPAR) modulators: The current pharmacological toolbox.

Lysophosphatidic acids (LPA) are key lipid-signalling molecules that regulate a remarkably diverse set of cellular events, such as motility, chemotaxis, cell cycle progression, viability, and wound healing. The physiological and pathophysiological consequences of LPA signalling are evident and misregulation of LPA signalling can lead to pathologies like cancer, atherosclerosis, ischaemia, and fibrosis. LPA exerts its biological actions mainly through several types of G protein-coupled receptors, some of which display opposing or redundant effects. For this reason, selective LPA receptor small-molecule ligands can shine light on LPA biology and present an exciting opportunity for drug discovery endeavours. This review provides insights into the detailed chemical nature and pharmacological profile of the small-molecules thus far developed as LPA receptor modulators, as well as information on the preparation of key pharmaceuticals. This summary will facilitate future research efforts and nurture collaboration between chemists and biologists working in this emerging field.

Solid phase synthesis of peptide-selenoesters.

The synthesis of proteins by native chemical ligation greatly enhances the application of chemistry to complex molecules such as proteins. The essential building blocks for this approach traditionally have been peptide-thioester segments that are linked chemoselectively in consecutive reactions. By using peptide selenoesters instead of thioesters, the ligation rate can be significantly accelerated permitting couplings at difficult sites and potentially enabling new ligation strategies. To facilitate the routine synthesis of selenoester peptides, a general and straightforward procedure has been developed that generates a suitably functionalized resin from which the desired selenoester peptide can be readily synthesized. This simple approach utilizes readily available and cheap chemical agents and enables production of peptide selenoesters of excellent quality in short time and with high recovery. In addition, the stability of peptide selenoesters was examined under different native chemical ligation conditions and compared to thioesters. Selenoesters are slightly more reactive and more susceptible to hydrolysis and aminolysis than thioesters but sufficiently stable under mildly acidic conditions (pH 6.5). Under these conditions, rapid selenoester-mediated ligation is kinetically favoured.

Efficient chemical synthesis of human complement protein C3a.

We report the total chemical synthesis of human C3a by one-pot native chemical ligation of three unprotected peptide segments, followed by efficient in vitro folding that yielded the anaphylatoxin C3a in high yield and excellent purity. Synthetic C3a was fully active and its crystal structure at 2.1 Å resolution showed 3 helices and a C-terminal turn motif.