ABSTRACT
The BCL2-specific inhibitor, venetoclax, has demonstrated remarkable clinical activity in the treatment of chronic lymphocytic leukemia (CLL), either alone or in combination with CD20 antibodies. Nevertheless, patients who fail to attain a complete remission relapse, and require further therapy. Data on retreatment with venetoclax at disease progression are currently limited. Here, we report patterns of clonal evolution in an R/R CLL patient that has demonstrated successful retreatment. A 57 year-old lady with chemotherapy- refractory (FCR, RCHOP, high dose methyl prednisolone) TP53 mutant CLL was treated for 21 months with single-agent venetoclax in 2014 (NCT01889186). She attained an MRD positive CR with the resolution of massive lymphadenopathy and with only low-level (0.01%) disease in the bone marrow. However, she subsequently progressed rapidly with a lymphocyte doubling time of only 4 weeks and was treated with tirabrutinib and idelalisib in combination (NCT02968563) from December 2015 for 37 months before progressing December 2019. She was retreated with venetoclax and rituximab but died of COVID-19-induced respiratory failure in March 2020. To study the clonal evolution underlying these events, in vitro drug sensitivity assays and whole exome sequencing (WES) were used to study peripheral blood mononuclear (PBMC) and bone marrow samples. WES of sample 1 showed multiple mutations in CLL driver genes: SF3B1 R625C, KMT2C R4434Q, and TP53 R110L at VAFs of 37, 17, 35%, respectively. Mutations in other genes associated with CLL included FANCA L217F (47%) and SPEN P3402S (46%). At disease progression (sample 2), following venetoclax, there was the loss of detectable (WES at 100× coverage) TP53 R110L (with loss of 17p deletion on interphase FISH and analysis of copy number) but maintenance of SF3B1 R625C (44%), KMT2C R4434Q 30%), FANCA L217F (47%), and SPEN P3402S (55%). These data, therefore, suggest the TP53 mutant subclone was largely lost during therapy. No other mutations were identified as possible resistance mediators. There were no detectable BCL2 mutations. In vitro drug sensitivity testing to venetoclax showed an EC50 of 228nM (CLL EC50 usually 3-5 nM). The patient was then treated with the BTK inhibitor tirabrutinib in combination with idelalisib, with an excellent clinical response. After 10 months (sample 3, during the lymphocytosis induced by BTKi/PI3Kdi) SF3B1, KMT2C, FANCA, and SPEN mutations were detected at VAFs of 26, 30, 54, and 56%, respectively. At this point the TP53 R110L mutation was detected again at a VAF of 4%, indicating that stopping venetoclax allowed the clone to re-emerge. At this time, there were no detectable BTK or PLCG2 mutations. The patient then responded for a further 37 months before disease progression. At progression (sample 4), SF3B1, KMT2C, FANCA, and SPEN mutations were still detected in the peripheral blood at VAFs of 43, 31, 48, and 50%, respectively. The VAF of the TP53 R110L mutation had increased to 33%. Additionally, a BTK mutation (T474I) was identified with a VAF of 16%. Identical results were obtained using a bone marrow sample. Now, however, in vitro analysis demonstrated a high degree of sensitivity to venetoclax (EC50 0.72 nM). The patient was, therefore, retreated with venetoclax and rituximab. At the point of re-treatment, VAFs were maintained, with the emergence of a new subclonal NOTCH1 G1001D mutation at a VAF of 3%. The patient, unfortunately, died 4 months after commencing therapy due to COVID-19 associated pneumonitis. A full disease reassessment was not made but the patient's blood count had normalized, with rapid clearance of CLL cells from the peripheral blood, recovery of normal hematological indices, resolution of splenomegaly, and partial resolution of lymphadenopathy on CT scan. These data, therefore, suggest that re-treatment with venetoclax in CLL can be successful. Regaining sensitivity to venetoclax may largely depend on shifting clonal dynamics. The molecular basis of venetoclax resistance in this case is currently being investigated. A so in this particular case, it appears that the TP53 mutant subclone was more sensitive to BCL2 inhibition than TP53 wild-type subclone(s), and was largely eliminated by initial venetoclax treatment, contrasting with recently published data suggesting resistance of TP53 mutant hematological malignancies to BCL2 inhibition due to increased thresholds for BAX/BAK activation (Thijssen et al., 2021).
ABSTRACT
AIM: Levamisole, an antiparasitic drug, was reported to have positive effects in various clinical trials in the treatment of COVID-19. However, the number of studies on the effects of levamisole on the reproductive system and sexual behavior in male rats is limited. The present study aimed to investigate the possible effects of levamisole on sexual behavior, testicular histopathology, serum gonadotropin, and testosterone levels in male rats. METHODS: Twenty male Sprague-Dawley rats were divided into two groups as control and levamisole were used. Rats were given levamisole (2 mg/kg) dissolved in distilled water for 30 days, while only distilled water was administered to the control group by oral gavage. Finally, sexual behavior tests (SBT) were performed for 30 min. Then, the animals were decapitated, blood samples and testis tissues were taken. The Bax, Hsp70 and cytochrome c immunohistochemistry staining were performed in testis tissues, and gene expression levels were measured by real-time PCR. The luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were measured by ELISA in serum samples. RESULTS: In SBT parameters, mount latency (ML, p<0.001), intromission latency (IL, p<0.01), and the postejaculatory interval (PEI, p<0.01) were significantly prolonged. Also, the copulatory rate (CR, p<0.05) was significantly reduced. Serum LH, FSH, and testosterone levels did not change. In the histopathological stainings, irregularities in the seminiferous tubule germinal epithelium, congestion, edema in the interstitial area, and metaphase arrest in some spermatocytes were detected in the levamisole group (p<0.001). Levamisole treatment also significantly increased cytochrome c, Bax, and Hsp 70 immunoreactivities and Bax (p=0.05) and Hsp 70 (p<0.01) gene expression levels in testicular tissue. CONCLUSION: Levamisole may decrease sexual motivation and copulation efficiency. Also, it may adversely affect testicular histopathology in male rats.
ABSTRACT
Comprehensive proteomic studies of HSC derived from bone marrow of healthy human subjects (n = 59) in different age groups (range: 20 - 72 years) showed that aging HSCs are characterized not only by myeloid lineage skewing, senescence associated secretory phenotype (SASP), accumulation of reactive oxygen species (ROS), anti-apoptosis, but prominently by elevated glycolysis, glucose uptake, and accumulation of glycogen. This is caused by a subset of HSC that has become more glycolytic than others and not on a per cell basis. Subsequent comparative transcriptome studies of HSCs from human subjects >60 years versus those from <30 years have confirmed this association of elevated glycolysis with aging transcriptome signature. Provided with this background and based on glucose metabolism levels, we have developed a method to isolate human HSCs (CD34+ cells) from bone marrow into three distinct subsets with high, intermediate, and low glucose uptake (GU) capacity (GU high, GU inter, GU low). For human subjects >60 years old (n=9), the proportions of these subsets are: GU high= 5.4+3.5 %, GU inter= 66.4+22.5 %, GU low= 28.2+21.7 %. For subjects <30 years (n=5), the proportions are GU high= 1.7+1.5 %, GU inter= 66.5+36.9 %, GU low= 31.8+36.7. Single-cell RNA-sequencing (scRNA-seq) studies and gene ontology analysis of biological processes revealed that, compared to the GU inter and GU low subsets, the GU high cells showed a significantly higher expression of genes involved in myeloid development, inflammation response (AIF1, CASP2, ANXA1, ZFP36), anti-apoptosis (GSTP1, NME1, BCL2, DMNT1, BAX), cell cycle checkpoint (MCL1, CDK1, CDK4, EIF5A), histone regulation (BCL6, EGR1, KDM1A, MLLT3), b-galactosidase, and significantly lower expressions of genes involved in lymphoid development, and of MDM4, MDM2, FOXP1, SOX4, RB1. Functional studies indicated that the glycolytic enzymes were elevated in elderly HSCs, and the GU low subset corresponded to primitive and more pluripotent HSCs than the GU interand GU high subsets. Pathway analyses have then demonstrated that the GU high subset is associated with up-regulated p53 as well as JAK/STAT signaling pathways, characteristic of senescent HSCs observed in murine models. Applying Gene Set Enrichment Analysis (GSEA) algorithms, we have compared the scRNA-seq data of CD34+ cells derived from young (<30 years) versus older (>60 years) subjects, as well as the scRNA-seq data from GU high subset versus GU inter and GU lowsubsets from each individual subject (n = 6). The results are shown in Figure 1. In analogy to the comparison between old (>60 years) versus young (<30 years) HSCs (CD34+ cells), GSEA of the GU high versus GU inter and GU low subsets shows the same pattern of changes - significant upregulation of gene-set expressions for (a) inflammatory response (b) G2M checkpoint, (c) MTORC1, (d) ROS, (Fig. 1B), (e) allograft rejection;and down-regulation of gene-set expressions for (f) pluripotency, (g) androgen response, (h) UV response (Fig. 1C) as well as (i) interferon-a induction during SARS-CoV2-infection (data not shown in Fig. 1). Thus, our novel findings of elevated glycolysis coupled with significant activation of MTORC1 in the senescent cells of the HSC compartment have provided evidence for the important role of calorie restriction (CR) for healthy aging of HSCs. In numerous animal models, aging has been shown to be driven by the nutrient-sensing MTORC1 network. In animal models of aging, CR has been reported to deactivate the MTOR pathway, thus slowing aging and delaying diseases of aging. Conclusion: In a series of multi-omics studies, we have demonstrated that the GU high subset is identical to the senescent cells (SCs) in human HSC compartment. Studies in animal models have shown that SCs in murine bone marrow are responsible for driving the aging process, and elimination of this subset by inhibitors of anti-apoptotic factors is able to rejuvenate hematopoiesis in mice. Our present results have provided cellular and molecular evidence that SCs in human HSC compartment re also dependent on anti-apoptotic factors, elevated MTORC1 as well as increased glycolysis for survival. Inhibition of MTORC1 or glycolysis, either by specific inhibitors or by CR, may eliminate senescent HSCs and promote rejuvenation of human hematopoiesis. [Formula presented] Disclosures: No relevant conflicts of interest to declare.