Fludarabine and Cladribine Induce Changes in Surface Proteins on Human B-Lymphoid Cell Lines Involved with Apoptosis, Cell Survival, and Antitumor Immunity

B-cell performance in chemotherapy: Unravelling the mystery of B-cell therapeutic potential

BACKGROUND AND MAIN BODY

The anti-tumour and tumour-promoting roles of B cells in the tumour microenvironment (TME) have gained considerable attention in recent years. As essential orchestrators of humoral immunity, B cells potentially play a crucial role in anti-tumour therapies. Chemotherapy, a mainstay in cancer treatment, influences the proliferation and function of diverse B-cell subsets and their crosstalk with the TME. Modulating B-cell function by targeting B cells or their associated cells may enhance chemotherapy efficacy, presenting a promising avenue for future targeted therapy investigations.

CONCLUSION

This review explores the intricate interplay between chemotherapy and B cells, underscoring the pivotal role of B cells in chemotherapy treatment. We summarise promising B-cell-related therapeutic targets, illustrating the immense potential of B cells in anti-tumour therapy. Our work lays a theoretical foundation for harnessing B cells in chemotherapy and combination strategies for cancer treatment.

KEY POINTS

Chemotherapy can inhibit B-cell proliferation and alter subset distributions and functions, including factor secretion, receptor signalling, and costimulation. Chemotherapy can modulate complex B-cell-T-cell interactions with variable effects on anti-tumour immunity. Targeting B-cell surface markers or signalling improves chemotherapy responses, blocks immune evasion and inhibits tumour growth. Critical knowledge gaps remain regarding B-cell interactions in TME, B-cell chemoresistance mechanisms, TLS biology, heterogeneity, spatial distributions, chemotherapy drug selection and B-cell targets that future studies should address.

In Vivo Imaging of Local Inflammation: Monitoring LPS-Induced CD80/CD86 Upregulation by PET

PURPOSE

The co-stimulatory molecules CD80 and CD86 are upregulated on activated antigen-presenting cells (APC). We investigated whether local APC activation, induced by subcutaneous (s.c.) inoculation of lipopolysaccharides (LPS), can be imaged by positron emission tomography (PET) with CD80/CD86-targeting 64Cu-labelled abatacept.

PROCEDURES

Mice were inoculated s.c. with extracellular-matrix gel containing either LPS or vehicle (PBS). Immune cell populations were analysed by flow cytometry and marker expression by RT-qPCR. 64Cu-NODAGA-abatacept distribution was analysed using PET/CT and ex vivo biodistribution.

RESULTS

The number of CD80+ and CD86+ immune cells at the LPS inoculation site significantly increased a few days after inoculation. CD68 and CD86 expression were higher at the LPS than the PBS inoculation site, and CD80 was only increased at the LPS inoculation site. CTLA-4 was highest 10 days after LPS inoculation, when CD80/CD86 decreased again. A few days after inoculation, 64Cu-NODAGA-abatacept distribution to the inoculation site was significantly higher for LPS than PBS (4.2-fold). Co-administration of unlabelled abatacept or human immunoglobulin reduced tracer uptake. The latter reduced the number of CD86+ immune cells at the LPS inoculation site.

CONCLUSIONS

CD80 and CD86 are upregulated in an LPS-induced local inflammation, indicating invasion of activated APCs. 64Cu-NODAGA-abatacept PET allowed following APC activation over time.

The interaction mechanism between fludarabine and human serum albumin researched by comprehensive spectroscopic methods and molecular docking technique

Fludarabine (Flu) is widely used to treat B-cell chronic lymphocytic leukemia. HSA is of the essence to human, especially in blood circulation system. The interaction mechanism between Flu and HSA was studied by comprehensive spectroscopic methods and molecular docking technique. UV-vis and FL spectrum results indicated that Flu bond with HSA, and there was a new complex produced at the binding site I in subdomain IIA. Association constants at 298 K were 1.637 × 10⁴ M^-1 and 1.552 × 10⁴ M^-1 at 310 K, respectively. The negative enthalpy (ΔH) and positive entropy (ΔS) values for the interaction revealed that the binding behavior was driven by hydrophobic forces and hydrogen bonds. The results obtained from UV, RLS spectra, 3D fluorescence and CD spectrum illustrated that Flu could change the secondary structure of HSA. According to molecule docking result, the binding energy of interaction is -11.15 kcal/mol.

Synthesis, characterization and biological evaluation of C5'-N-cyclopropylcarboxamido-C6-amino-C2-alkynylated purine nucleoside analogues

In an effort to develop potent antibacterial and anticancer agents, a series of C5'-N-cyclopropylcarboxamido-C6-amino-C2-alkynylated purine nucleoside analogues 11a-g were synthesized through a Sonogashira cross-coupling reaction. The nine-step synthesis is easy to perform, and employs commercially available reagents. 2-Iodo-5'-N-cyclopropylcarboxamidoadenosine (9) was used as the starting intermediate for the synthesis of title derivatives 11a-g. Synthetic intermediates (2-9) and final products (11a-g) were appropriately characterized by IR, ¹H NMR, ¹³C NMR and mass spectroscopy. The synthesized purine nucleoside analogues (11a-g) were evaluated for their in vitro antibacterial activity against two gram-positive and two gram-negative bacteria. They were then tested for cytotoxicity against MDA-MB-231 and Caco-2 cancer cell lines to determine their anti-cancer activity. Among the tested compounds, compounds 11c and 11g showed most potent antibacterial activity against S.aureus and P.aeruginosa bacterial strains. Compounds 11b and 11e displayed considerable IC₅₀^s of 7.9 and 6.8 µg/mL, respectively, vs MDA-MB-231 cell lines of 7.5 and 8.3 µg/mL, respectively, against the Caco-2 cell lines.

From genome to proteome: Looking beyond DNA and RNA in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) remains the most common leukemia in the Western world. Whilst its disease course is extremely heterogeneous (ranging from indolent to aggressive), current methods are unable to accurately predict the clinical journey of each patient. There is clearly a pressing need for both improved prognostication and treatment options for patients with this disease. Whilst molecular studies have analyzed both genetic mutations and gene expression profiles of these malignant B-cells, and as a result have shed light on the pathogenesis of CLL, proteomic studies have been largely overlooked to date. This review summarizes our current knowledge of the proteomics of CLL, and discusses some of the issues in CLL proteomic research, such as reproducibility and data interpretation. In addition, we look ahead to how proteomics may significantly help in the development of a successful treatment for this currently incurable disease.

Mechanisms of action of fludarabine nucleoside against human Raji lymphoma cells

Fludarabine (2-FaraAMP) is a purine analog that is effective against chronic lymphocytic leukemia (CLL) and non-Hodgkins lymphoma (NHL). For some cases of CLL, 2-FaraAMP as a single agent can clear the blood of leukemia cells, but leukemia stem cells usually remain protected in sanctuary sites. It is clear that 2-FaraAMP has multiple mechanisms of action that may collectively result in strand breaks in DNA, accumulation of phosphorylated p53 and apoptosis. We have demonstrated using the human Burkitt's lymphoma B-cell line, Raji, that p53, p63 and p73 all accumulate in the nucleus, following treatment of cells with fludarabine nucleoside (2-FaraA). In addition, phosphorylated p53 accumulates in the cytosol and at mitochondria. Using sophisticated methods of proteomic analysis with mass spectrometry, proteins that become differentially abundant after treatment of cells with 2-FaraA have been identified, providing considerable additional information about the cellular responses of B-lymphoid cancers to this purine analog. The levels of proteins involved in the unfolded protein response increase, indicating that endoplasmic reticulum stress is likely to be one mechanism for induction of apoptosis. The levels of a number of proteins found on the outer plasma membrane change on cells treated with 2-FaraA, suggesting that signaling from the B-cell antigen receptor (BCR) is stimulated, resulting in induction of apoptosis through the intrinsic pathway. Increased levels of the cell surface proteins, CD50, CD100 and ECE-1, would promote survival of these cells; the balance between these survival and death responses would determine the fate of the cell.

Successful transplantation of kidney allografts in sensitized rats after syngeneic hematopoietic stem cell transplantation and fludarabine

Current methods to remove donor-specific HLA antibody (DSA) from sensitized patients remain imperfect. We tested novel approaches to desensitization using an animal model of allogeneic sensitization with skin grafts from dark agouti (DA) to Lewis rats. At the peak IgG alloantibody response we transplanted DA kidneys into nephrectomized Lewis recipients (n = 6) and all died within 10 days from antibody-mediated rejection (AMR). Allogeneic hematopoietic stem cell transplants (HSCT) from DA donors failed to engraft after lethal or sub-lethal irradiation. Sensitized rats given lethal irradiation plus syngeneic green fluorescent protein (GFP) + HSCT had repopulation of blood, spleen, thymus and lymph nodes by GFP+ cells. At 2 months after HSCT, serum DSA levels were reduced 60-70% and DSA (IgG) production in cultured splenocytes was also significantly decreased. However, there was only a modest improvement in graft survival from an average of 6.5 to 13.9 (n = 9) days. Adding seven daily doses of fludarabine to the preconditioning regimen resulted in long-term survival (>90 days) in 7 out of 10 rat kidney allografts. We conclude that syngeneic HSCT performed after preconditioning with irradiation and fludarabine can reduce DSA, prevent DSA rebound and AMR, enabling successful transplantation in animals with strong antibody reactivity to the donor MHC.