Drug repurposing: Ibrutinib exhibits immunosuppressive potential in organ transplantation

Effect of rituximab in patients with PLA2R-associated membranous nephropathy and malignancy

INTRODUCTION

Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) is a common cause of nephrotic syndrome in nondiabetic adults who are also within the common age group for malignancy. How to treat patients with PLA2R-associated MN and malignancy effectively and safely still requires careful consideration. The aim of our study was to examine the outcomes and safety of rituximab (RTX) in these patients.

METHODS

Retrospective analysis of clinical data was performed on 15 patients with PLA2R-associated MN and malignancy. Patients were followed every 1-3 months for a minimum of 24 months. Clinical data were collected, including CD19+ B cells, anti-PLA2R antibodies, 24-hour urinary protein, serum albumin, and serum creatinine. The percentage of patients who achieved clinical remission and immunological remission was also measured.

RESULTS

Among these 15 patients, 14 patients with solid tumors received treatment for malignant diseases with complete resection. One patient received chemotherapy for chronic myeloid leukemia, and achieved complete remission 36 months before the diagnosis of MN. There were 6 (40.00 %) patients who achieved complete remission and 14 (93.33 %) patients who achieved complete or partial remission at the last visit after RTX treatment. At the last visit, patients were clinically improved, as evidenced by significant improvements in anti-PLA2R antibody titer [2.00 (2.00, 2.00) vs 35.25 (11.18, 91.58) RU/ml, P = 0.002], 24-hour urine protein [0.39 (0.11, 2.28) vs 9.22 (4.47, 14.73) g/d, P = 0.001], and serum albumin [38.15 (34.80, 43.20) vs 23.70 (18.70, 25.70) g/L, P = 0.001]. During the follow-up, the renal function of those patients remained stable. Recurrence of malignant tumors or the occurrence of new tumor events were not observed.

CONCLUSION

In this single-center retrospective study with a small sample size, RTX therapy might be an effective and safe treatment in patients with PLA2R-associated MN and malignancy.

Underlying Ciliary Body Uveal Melanoma in a Patient with Chronic Lymphocytic Leukemia Presenting for Hyphema

(1) Background: Ciliary body uveal melanoma is a rare subtype of uveal melanoma which comprises 3–5% of melanomas, an immunogenic cancer, and can present multifaceted initial clinical manifestations, masquerading as various ocular pathologies. Chronic lymphocytic leukemia (CLL) presents immunodeficiency and risk for the development of a secondary malignancy, with Bruton’s tyrosine kinase inhibitor treatment having a mutagenic effect and a secondary anti-platelet aggregation effect. We present the case of a 65-year-old patient undergoing treatment for CLL with ibrutinib who presented with recurrent hyphema that masked an underlying, inferiorly situated, ciliary body uveal melanoma; (2) Methods: Retrospective case review; (3) Results: An ophthalmological examination together with imaging via mode B ultrasound and contrast-enhanced magnetic resonance imaging resulted in the clinical and imagistic diagnosis of a ciliary body uveal melanoma. A pathological examination of the enucleated eye confirmed the diagnosis. Postoperative tumoral reoccurrence was not detected for 1½ years, however, CLL immunosuppression worsened with admission for severe COVID-19 disease. (4) Conclusions: CLL patient screening for melanoma should also include detailed ophthalmological examinations, which could also include ultrasound ophthalmological imaging. The avoidance of uveal melanoma metastatic disease is paramount for patient survival. CLL manifests additional profound immunosuppression.

Insights into the effects of difenoconazole on the livers in male mice at the biochemical and transcriptomic levels

Difenoconazole (DFZ) is a broad-spectrum triazole fungicide, that is extensively used in agriculture. Studies have shown that residues of DFZ and other fungicides have toxic effects on nontarget organisms. However, its hepatoxicity in mammals remains unclear. Here, we characterized the toxic hepatic effects in male C57BL/6 mice exposed to 30 and 100 mg/kg bw DFZ for 14 and 56 days, respectively. The results revealed that DFZ could increase the relative liver weights, however, the relative fat and spleen weights decreased. More importantly, DFZ exposure changed the hepatic morphology and induced hepatic oxidative stress. Gene expression analysis suggested that DFZ could induce a glycolipid metabolism disorder. Moreover, hepatic transcriptomic analysis revealed the effects of DFZ exposure on the transcriptional levels of various genes, and enrichment analysis of differentially expressed genes (DEGs) showed that energy metabolism and immune-associated pathways were mainly affected. We validated the results from transcriptomic analysis and found that some key genes related to energy metabolism were affected. In addition, flow cytometry showed that the CD3+/CD4+ and CD3+ /CD8+ levels declined in the spleen of mice. Taken together, these findings combined with transcriptome analysis highlighted that DFZ caused different endpoints in the liver, which could provide more evidence for investigating the toxic effects of DFZ in mammals.

Clinical Trials of the BTK Inhibitors Ibrutinib and Acalabrutinib in Human Diseases Beyond B Cell Malignancies

The BTK inhibitors ibrutinib and acalabrutinib are FDA-approved drugs for the treatment of B cell malignances. Both drugs have demonstrated clinical efficacy and safety profiles superior to chemoimmunotherapy regimens in patients with chronic lymphocytic leukemia. Mounting preclinical and clinical evidence indicates that both ibrutinib and acalabrutinib are versatile and have direct effects on many immune cell subsets as well as other cell types beyond B cells. The versatility and immunomodulatory effects of both drugs have been exploited to expand their therapeutic potential in a wide variety of human diseases. Over 470 clinical trials are currently registered at ClinicalTrials.gov to test the efficacy of ibrutinib or acalabrutinib not only in almost every type of B cell malignancies, but also in hematological malignancies of myeloid cells and T cells, solid tumors, chronic graft versus host disease (cGHVD), autoimmune diseases, allergy and COVID-19 (http:www.clinicaltrials.gov). In this review, we present brief discussions of the clinical trials and relevant key preclinical evidence of ibrutinib and acalabrutinib as monotherapies or as part of combination therapies for the treatment of human diseases beyond B cell malignancies. Adding to the proven efficacy of ibrutinib for cGVHD, preliminary results of clinical trials have shown promising efficacy of ibrutinib or acalabrutinib for certain T cell malignancies, allergies and severe COVID-19. However, both BTK inhibitors have no or limited efficacy for refractory or recurrent solid tumors. These clinical data together with additional pending results from ongoing trials will provide valuable information to guide the design and improvement of future trials, including optimization of combination regimens and dosing sequences as well as better patient stratification and more efficient delivery strategies. Such information will further advance the precise implementation of BTK inhibitors into the clinical toolbox for the treatment of different human diseases.

The novel immunosuppressant prenylated quinolinecarboxylic acid-18 (PQA-18) suppresses macrophage differentiation and cytotoxicity in xenotransplantation

Innate immunity plays a major role in xenograft rejection. However, the majority of immunosuppressants focus on inhibiting acquired immunity and not innate immunity. Therefore, a novel immunosuppressant suitable for use in conjunction with xenografts continues to be needed. It has been reported that prenylated quinolinecarboxylic acid-18 (PQA-18), a p21-activated kinase 2 (PAK2) inhibitor, exerts an immunosuppressive function on T cells. Hence, the possibility exists that PQA-18 might be used in conjunction with xenografts, which prompted us to investigate the efficacy of PQA-18 on macrophages compared with Tofacitinib, a janus kinase (JAK) inhibitor. Initial experiments confirmed that PQA-18 is non-toxic to swine endothelial cells (SECs) and human monocytes. Both PQA-18 and Tofacitinib suppressed macrophage-mediated cytotoxicity in both the differentiation and effector phases. Both PQA-18 and tofacitinib suppressed the expression of HLA-ABC by macrophages. However, contrary to Tofacitinib, PQA-18 also significantly suppressed the expression of CD11b, HLA-DR and CD40 on macrophages. PQA-18 significantly suppressed CCR7 expression on day 3 and on day 6, but Tofacitinib-induced suppression only on day 6. In a mixed lymphocyte reaction (MLR) assay, PQA-18 was found to suppress Interleukin-2 (IL-2)-stimulated T cell proliferation to a lesser extent than Tofacitinib. However, PQA-18 suppressed xenogeneic-induced T cell proliferation more strongly than Tofacitinib on day 3 and the suppression was similar on day 7. In conclusion, PQA-18 has the potential to function as an immunosuppressant for xenotransplantation.