Bovine leukemia virus (BLV) has spread worldwide and causes serious problems in the cattle industry owing to the lack of effective treatments and vaccines. BLV is transmitted via horizontal and vertical infection, and cattle with high BLV proviral load (PVL), which is a useful index for estimating disease progression and transmission risk, are considered major infectious sources within herds. PVL strongly correlates with highly polymorphic bovine lymphocyte antigen (BoLA)-DRB3 alleles. The BoLA-DRB3*015:01 and *012:01 alleles are known susceptibility-associated markers related to high PVL, and cattle with susceptible alleles may be at a high risk of BLV transmission via direct contact with healthy cows. In contrast, the BoLA-DRB3*009:02 and *014:01:01 alleles comprise resistant markers associated with the development of low PVL, and cattle with resistant alleles may be low-risk spreaders for BLV transmission and disrupt the BLV transmission chain. However, whether polymorphisms in BoLA-DRB3 are useful for BLV eradication in farms remains unknown. Here, we conducted a validation trial of the integrated BLV eradication strategy to prevent new infection by resistant cattle and actively eliminate susceptible cattle in addition to conventional BLV eradication strategies to maximally reduce the BLV prevalence and PVL using a total of 342 cattle at 4 stall barn farms in Japan from 2017 to 2019. First, we placed the resistant milking cattle between the BLV-positive and -negative milking cattle in a stall barn for 3 years. Interestingly, the resistant cattle proved to be an effective biological barrier to successfully block the new BLV infections in the stall barn system among all 4 farms. Concomitantly, we actively eliminated cattle with high PVL, especially susceptible cattle. Indeed, 39 of the 60 susceptible cattle (65%), 76 of the 140 neutral cattle (54%), and 20 of the 40 resistant cattle (50%) were culled on 4 farms for 3 years. Consequently, BLV prevalence and mean PVL decreased in all 4 farms. In particular, one farm achieved BLV-free status in May 2020. By decreasing the number of BLV-positive animals, the revenue-enhancing effect was estimated to be \5,839,262 for the 4 farms over 3 years. Our results suggest that an integrated BLV eradication program utilization of resistant cattle as a biological barrier and the preferential elimination of susceptible cattle are useful for BLV infection control.

Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis, the most prevalent neoplastic disease of cattle worldwide. The immune response to BLV and disease susceptibility and resistance in cattle are strongly correlated with the bovine leukocyte antigen (BoLA)-DRB3 allelic polymorphism. BLV infection continues to spread in Egypt, in part because the relationships between BLV infection, proviral load in Egypt, and BoLA-DRB3 polymorphism are unknown. Here, we identified 18 previously reported alleles in 121 Holstein cows using a polymerase chain reaction sequence-based typing method. Furthermore, BoLA-DRB3 gene polymorphisms in these animals were investigated for their influence on viral infection. BoLA-DRB3*015:01 and BoLA-DRB3*010:01 were identified as susceptible and resistant alleles, respectively, for BLV infection in the tested Holsteins. In addition, BoLA-DRB3*012:01 was associated with low PVL in previous reports but high PVL in Holstein cattle in Egypt. This study is the first to demonstrate that the BoLA-DRB3 polymorphism confers resistance and susceptibility to PVL and infections of BLV in Holstein cattle in Egypt. Our results can be useful for the disease control and eradication of BLV through genetic selection.

Cancer is characterized by abnormal cell growth and remains a leading global cause of death despite advances in conventional therapies. Limitations such as lack of selectivity, cytotoxic side effects, and multidrug resistance underscore the need for potent anticancer agents. Topoisomerase II (TOP2) has emerged as a pivotal target for anticancer drugs, categorized as poisons and catalytic inhibitors. While clinically used TOP2-based drugs predominantly act as poisons, concerns regarding their cytotoxicity and DNA-damaging potential persist. In response to these challenges, exploring natural bioactive compounds (NBCs), including small molecules from Chinese herbs, as sources of novel anticancer agents has become a focal point in pharmaceutical research. Recognizing that NBCs alone may not satisfy as anticancer agents, this review aims to comprehensively analyze the current published studies, specifically focusing on the combined applications of TOP2-inhibiting approved chemotherapeutics and natural products. The review explores this approach's potential synergies and challenges, emphasizing the importance of developing effective and targeted anticancer strategies.

Cyclophosphamide (CTX) is a chemotherapeutic drug used to treat mammary gland tumors. Despite its cytotoxic effect on cancer cells, it causes harm to hepatic and renal tissues, ranging from mild infiltration to necrosis and finally cytolysis, depending on the dosage and duration of treatment. It also suppresses bone marrow, resulting in leukopenia, anemia, and thrombocytopenia. This study aimed to evaluate the protective effects of concanavalin A (con-A) and IL-27 conditioned immune therapeutics on Ehrlich ascites carcinoma (EAC) tumor-bearing mice treated with CTX. To achieve this, naive splenocyte cells were activated in vitro for 3 days with the T cell mitogen concanavalin A (Con-A; 5 µg/mL) and/or IL-27 (10; ng/mL). After a single i/p injection of CTX (4 mg/mouse), they were adoptively transferred into (EAC) tumor-bearing mice. After tumor implantation, hematological analysis, liver function, and kidney function were evaluated. According to the findings, the CTX-treated group had significantly lower total leucocyte count, lymphocytes, neutrophils, hematocrit, and RBCs than the control group. Interestingly, Con-A + IL-27 normalized the total leucocytes' count, especially lymphocytes and neutrophils. When Con-A + IL-27 was compared to CTX, there was a significant increase in hematocrit and platelet count. AST, ALT, bilirubin, creatinine, and urea levels were not significantly different between normal and Con-A + IL-27, but CTX significantly increased AST compared to normal. According to the findings, adoptive transfer of Con-A + IL-27 conditioned splenocyte cells into lymphopenic hosts restored hematological and biochemical parameters and recovery from chemotherapy-induced lymphopenia.

Bovine leukemia virus (BLV) is the etiological agent of B‐cell leukemia/lymphoma in cattle worldwide. Although previous studies have linked BLV to breast cancer in women, its zoonotic potential remains controversial. Moreover, no previous studies have clearly investigated the BLV latency in human cells. In this study, we aimed to establish and characterize human cell lines stably infected with BLV as in vitro models of natural BLV infection. Human epithelial 293T, human cervical cancer HeLa cells (HeLa), and human breast cancer MCF7 cells were infected with cell‐free virus from persistently infected fetal lamb kidney (FLK–BLV) cultures. Single clones of the three infected cell lines were tested every 2 weeks for 18 months. The three infected clones maintained the full‐length BLV provirus. None of the three infected cell lines showed cellular expression of viral gp51 and p24 proteins, cell‐to‐cell infectivity, or detectable virion p24 and RNA throughout the study, indicating BLV silencing in human cells. A significant delay in the doubling time of BLV‐infected 293T and MCF7 cells with cytopathic effects on cellular morphology was observed after BLV latency. The findings revealed that latent BLV‐induced apoptosis in 293T and MCF7 cells but not in HeLa. Additionally, analysis of apoptosis‐related pathways showed that BLV infection did not increase expression of antiapoptotic markers in all infected cell lines. In conclusion, we successfully established three stably infected human cell lines by BLV silencing. Of critical importance to public health, human cells latently infected with BLV undergo apoptosis but not malignant transformation. Further studies to analyze the mechanisms of BLV–human interaction in established models are in progress.

Bovine leukemia virus (BLV), a major cause of B-cell lymphoma in cattle worldwide, has been linked to human breast cancer. Here, we performed comparative whole-transcriptome analysis of single clones of human epithelial 293T, breast cancer MCF7, and cervical cancer HeLa cells, stably infected with BLV, versus uninfected controls using RNA-sequencing technology. Differential expression analysis revealed 2050, 1314, and 2772 differentially expressed genes (DEGs) between BLV-infected 293T, MCF7, and HeLa cells and controls, respectively. Most DEGs were upregulated in BLV-infected 293T (76.5%) and MCF7 (69.1%) cells but downregulated in HeLa cells (62.0%). Functional enrichment analyses revealed enrichment of “Gene expression” and “Membrane Trafficking” pathways across all cell lines, and that of “Apoptosis” and “Axon guidance” pathways uniquely in 293T and MCF7 cells. Twenty genes linked to apoptosis of 293T and MCF7 cells were identified, and expression of 11 of these was confirmed using quantitative real-time PCR. The expression of EFEMP1 and LXN, which showed the greatest fold change, was validated: EFEMP1 knockdown and LXN overexpression inhibited cell proliferation, induced apoptosis, and altered growth morphology of 293T and MCF7 cells. This is the first transcriptome profiling of human cells during BLV latency, which should help understand the behavior of BLV.