Background: CD59, a GPI-anchored membrane protein, protects cancer cells from complement-dependent cytotoxicity (CDC) by inhibiting the formation of the membrane attack complex (MAC). It has been demonstrated to be overexpressed in most solid tumors, where it facilitates tumor cell escape from complement surveillance. The role of CD59 in cancer growth and interactions between CD59 and immune cells that modulate immune evasion has not been well explored. Methods: Using cancer patient database from The Cancer Genome Atlas (TCGA) and other public databases, we analyzed CD59 expression, its prognostic significance, and its association with immune cell infiltration in the tumor microenvironment, identifying associated genomic and functional networks and validating findings with invitro cell-line experimental data. Results: This article describes the abundant expression of CD59 in multiple tumors such as cervical squamous cell carcinoma (CESC), kidney renal cell carcinoma (KIRC), glioblastoma multiforme (GBM), head and neck squamous cell carcinoma (HNSC), and stomach adenocarcinoma (STAD), as well as in pan-cancer, using The Cancer Genome Atlas (TCGA) database and confirmed using multiple cancer cell lines. The expression of CD59 significantly alters the overall survival (OS) of patients with multiple malignancies such as CESC, GBM, HNSC, and STAD. Further, the correlation between CD59 and Treg and/or MDSC in the tumor microenvironment (TME) has shown to be strongly associated with poor outcomes in CESC, GBM, HNSC, and STAD as these tumors express high FOXP3 compared to KIRC. Moreover, unfavorable outcomes were strongly associated with the expression of CD59 and M2 tumor-associated macrophage infiltration in the TME via the IL10/pSTAT3 pathway in CESC and GBM but not in KIRC. In addition, TGFβ1-dominant cancers such as CESC, GBM, and HNSC showed a high correlation between CD59 and TGFβ1, leading to suppression of cytotoxic T cell activity. Conclusion: Overall, the correlation between CD59 and immune cells predicts its prognosis as unfavorable in CESC, GBM, HNSC, and STAD while being favorable in KIRC.

Breast cancer, ranking as the second leading cause of female cancer-related deaths in the U.S., demands the exploration of innovative treatments. Repurposing FDA-approved drugs emerges as an expedited and cost-effective strategy. Our study centered on proguanil, an antimalarial drug, reveals notable anti-proliferative effects on diverse breast cancer cell lines, including those derived from patients. Proguanil-induced apoptosis was associated with a substantial increase in reactive oxygen species (ROS) production, leading to reduced mitochondrial membrane potential, respiration, and ATP production. Proguanil treatment upregulated apoptotic markers (Bax, p-H2AX, cleaved-caspase 3, 9, cleaved PARP) and downregulated anti-apoptotic proteins (bcl-2, survivin) in breast cancer cell lines. In female Balb/c mice implanted with 4T1 breast tumors, daily oral administration of 20 mg/kg proguanil suppressed tumor enlargement by 55%. Western blot analyses of proguanil-treated tumors supported the in vitro findings, demonstrating increased levels of p-H2AX, Bax, c-PARP, and c-caspase3 as compared to controls. Our results collectively highlight proguanil’s anticancer efficacy in vitro and in vivo in breast cancer, prompting further consideration for clinical investigations.

Background/Objectives: CD318 (also known as CDCP1) is a transmembrane protein that is overexpressed in many cancers and contributes to tumor progression, invasion, and metastasis by activating SRC family kinases through phosphorylation. Emerging evidence also suggests that CD318 plays a role in modulating the tumor immune microenvironment, although its precise mechanism in tumor progression is still not well understood. Methods: To investigate this, we analyzed the expression and immune-related functions of CD318 using the publicly available data from The Cancer Genome Atlas (TCGA) across colorectal adenocarcinoma (COAD), cervical squamous cell carcinoma (CESC), lung adenocarcinoma (LUAD), and pancreatic adenocarcinoma (PAAD). Results: All four cancers exhibited a high level of CD318 expression. Notably, in CESC, LUAD, and PAAD, plasmin-mediated cleavage of CD318 leads to phosphorylation of SRC and protein kinase C delta (PKCδ), which activates HIF1α and/or p38 MAPK. These downstream effectors translocate to the nucleus and promote the transcriptional upregulation of TGFβ1, fostering an immunosuppressive tumor microenvironment through Treg cell recruitment. In contrast, this signaling cascade appears to be absent in COAD. Instead, our analysis indicate that intact CD318 in COAD interacts with the surface receptors CD96 and CD160, which are found on CD8⁺ T cells and NK cells. Conclusions: This interaction enhances cytotoxic immune responses in COAD by promoting CD8⁺ T cell and NK cell activity, offering a possible explanation for the favorable prognosis associated with high CD318 expression in COAD, compared to the poorer outcomes observed in CESC, LUAD, and PAAD.

Viral infection is a significant cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (Allo-HSCT), largely due to its impact on and interaction with immune reconstitution. Both innate and adaptive immunity are essential for effective viral control, yet their recovery post-transplant is often delayed or functionally impaired. Emerging evidence suggests genetic variation, particularly polymorphisms in the IL28B gene (encoding IFN-λ3), as a critical factor influencing the quality and timing of immune responses during the early post-transplant period. This review explores the role of IL28B polymorphisms in shaping antiviral immunity, in general, as well as after Allo-HSCT. IL28B variants have been implicated in modulating interferon-stimulated gene (ISG) expression, natural killer (NK) cell activity, and type I/III interferon signaling, all central components of innate immune defense against viral infections. Furthermore, IL28B polymorphisms, particularly rs12979860, have been shown in both general populations and limited HSCT cohorts to alter T cell response and interferon production, affecting reactivation and clearance of multiple viruses such as cytomegalovirus (CMV), hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein–Barr virus (EBV), COVID-19, and BK polyomavirus (BKPyV) as well as Graft vs. Host disease, thereby affecting adaptive immune reconstitution and long-term viral control. Understanding how IL28B genotype alters immune dynamics in transplant recipients could enhance risk stratification for CMV and other diseases and inform personalized prophylactic or therapeutic strategies. Therefore, this review highlights IL28B as a promising biomarker and potential immunoregulatory target in the management of viral infection post-Allo-HSCT.

CD24 is an emerging innate immune checkpoint that regulates inflammatory and antiviral immune responses through interactions with Siglec family receptors. Although CD24 has been extensively studied in immune regulation and has recently gained attention as a therapeutic target in infectious and inflammatory diseases, its role in cancer remains incompletely understood. CD24 is overexpressed in multiple human malignancies, where accumulating evidence suggests that it promotes tumor progression and immune evasion through activation of diverse intracellular and extracellular signaling pathways. However, the importance of its subcellular localization and associated signaling remains poorly defined. Here, we investigated CD24 expression, localization, signaling associations, immune-cell infiltration, and clinical outcomes using publicly available cancer datasets, focusing on breast cancer (BRCA), cervical squamous cell carcinoma (CESC), and glioblastoma multiforme (GBM). Our analyses revealed prominent membrane-associated CD24 localization in BRCA and CESC, whereas CD24 was predominantly cytoplasmic in GBM. BRCA and CESC exhibited increased integrin β1 expression and distinct associations between CD24 and components of integrin β1/SRC and TGFβ-associated signaling networks, including MEK1 and SMAD7. In addition, we identified a structurally consistent and energetically favorable predicted interface between CD24 and Siglec-10, suggesting a mechanism by which CD24 may suppress anti-tumor immunity. Elevated CD24 expression was associated with immune-infiltration patterns consistent with an immunosuppressive tumor microenvironment in BRCA and CESC, including negative associations with M1 macrophage, CD8⁺ T-cell, and NK-cell infiltration. Importantly, high CD24 expression was associated with unfavorable overall survival in BRCA and CESC, whereas the opposite relationship was observed in GBM. Collectively, these findings suggest that the subcellular distribution of CD24 may be associated with distinct tumor signaling, the immune microenvironment, and prognostic profiles, highlighting the potential importance of CD24 localization in determining its tumor-type-specific biological functions.

Breast cancer is a serious disease and the second leading cause of cancer-related death among women in the U.S. New treatments for this aggressive disease are urgently needed. Repurposing FDA-approved drugs for cancer treatment is an alternative that saves time and lowers the costs needed for drug development. In this study, we investigated the effects of proguanil, an anti-malarial drug, in breast cancer cells. Proguanil exhibited a significant cytotoxic effect on breast cancer cell lines including patient derived cell lines. Proguanil caused apoptosis through increased production of ROS and consequent decrease of mitochondrial membrane potential, mitochondrial respiration, and ATP production rates. ROS generation by proguanil was up to 3-fold higher when compared to the control. Proguanil treatment increased the expression of Bax, p-H2AX, cleaved-caspase 9, cleaved PARP, and down-regulated bcl-2 and survivin in breast cancer cell lines. The enlargement of 4T1 breast tumors in female Balb/c mice was suppressed by 55% through daily oral administration of 20mg/kg of proguanil. Western blot analyses of proguanil- treated tumors showed increased levels of p-H2AX, Bax, c-PARP, and c-caspase3 compared to control. Proguanil proved to be an efficient in vitro and in-vivo inhibitor of breast cancer cells, hence should be considered further for clinical investigation against breast cancer.