Molecular Mechanisms of Kaposi Sarcoma Development

Anaplastic Kaposi Sarcoma of the Right Colon, in a Young Man With Acquired Immunodeficiency Syndrome: A Rare Variant in an Unreported Organ

Kaposi sarcoma (KS) arises in the context of 4 epidemiologic-clinical settings: Classic, endemic, epidemic, and iatrogenic; the most serious types are endemic and epidemic, and visceral involvement occurs mostly in the latter. Several morphological variants of KS have been described, of which the anaplastic one is highly aggressive. We report the case of an anaplastic KS arising from the ascending colon in a 32-year-old human immunodeficiency virus (HIV)-positive male patient with a 6-year history of multiple mucocutaneous KS. Anaplastic KS is most frequent in endemic and classic settings; there are ten cases of anaplastic KS reported in HIV-positive male patients. There is now strong evidence that KS is a clonal neoplasm characterized by chromosomal instability at the molecular level. According to the morphological spectrum and contemporary hypotheses of oncogenesis, conventional KS should be considered an incipient endothelial neoplasia, multiple or single, and anaplastic KS, the fully developed stage of the malignant neoplasm.

EZH2-Myc Hallmark in Oncovirus/Cytomegalovirus Infections and Cytomegalovirus' Resemblance to Oncoviruses

Approximately 15-20% of global cancer cases are attributed to virus infections. Oncoviruses employ various molecular strategies to enhance replication and persistence. Human cytomegalovirus (HCMV), acting as an initiator or promoter, enables immune evasion, supporting tumor growth. HCMV activates pro-oncogenic pathways within infected cells and direct cellular transformation. Thus, HCMV demonstrates characteristics reminiscent of oncoviruses. Cumulative evidence emphasizes the crucial roles of EZH2 and Myc in oncogenesis and stemness. EZH2 and Myc, pivotal regulators of cellular processes, gain significance in the context of oncoviruses and HCMV infections. This axis becomes a central focus for comprehending the mechanisms driving virus-induced oncogenesis. Elevated EZH2 expression is evident in various cancers, making it a prospective target for cancer therapy. On the other hand, Myc, deregulated in over 50% of human cancers, serves as a potent transcription factor governing cellular processes and contributing to tumorigenesis; Myc activates EZH2 expression and induces global gene expression. The Myc/EZH2 axis plays a critical role in promoting tumor growth in oncoviruses. Considering that HCMV has been shown to manipulate the Myc/EZH2 axis, there is emerging evidence suggesting that HCMV could be regarded as a potential oncovirus due to its ability to exploit this critical pathway implicated in tumorigenesis.

Valganciclovir modulates the tumor necrosis factor axis molecules expression and CD4+ T-cell subsets in disseminated Kaposi Sarcoma patients

Valganciclovir (VGC) was used in a randomized clinical trial in patients with disseminated Kaposi Sarcoma/human immunodeficiency virus (DKS/HIV) as add-on therapy to evaluate the proinflammatory axis tumor necrosis factor (TNF) and its receptors (TNFRs) in T cells. Two treatment schedules were used: an experimental regime (ER) and a conventional treatment (CT). Mononuclear cells from patients with DKS/HIV were obtained at baseline (W0), 4 (W4), and 12 weeks (W12). Ten DKS/HIV patients received CT (antiretroviral therapy [cART]) and 10 ER (valganciclovir [VGC] initially, plus cART at the fourth week). HIV+ without KS and HIV- patient groups were included as controls. Correlation between T-cell subsets and HHV-8 viral load (VL) and a multivariate linear regression was performed. Data showed that DKS/HIV patients have an increased frequency of CD8+ T cells, which display a high density of CD8 expression. The ER scheme increases naïve and central memory CD4+ T cells at W4 and W12 of follow-up and induces a balanced distribution of activated CD4+ T-cell subsets. Moreover, ER decreases solTNFR2 since W4 and CT decreased the transmembrane forms of TNF axis molecules. Although CT induces a positive correlation between HHV-8 VL and TNFRs, the use of ER positively correlates with TNF and TNFRs levels through follow-up and a moderate correlation with HHV-8 VL and TNF soluble levels. In conclusion, VGC, as an add-on therapy in DKS/HIV patients, gradually modulates the activation of CD4+ T-cell subsets and the TNF/TNFRs axis, suggesting a better regulation of the inflammatory status.

Cancer and HIV: The Molecular Mechanisms of the Deadly Duo

The immune deficiency associated with human immunodeficiency virus (HIV) infection causes a distinct increased risk of developing certain cancer types. Kaposi sarcoma (KS), invasive cervical cancer and non-Hodgkin's lymphoma (NHL) are the prominent malignancies that manifest as a result of opportunistic viral infections in patients with advanced HIV infection. Despite the implementation of antiretroviral therapy (ART), the prevalence of these acquired immunodeficiency syndrome (AIDS)-defining malignancies (ADMs) remains high in developing countries. In contrast, developed countries have experienced a steady decline in the occurrence of these cancer types. However, there has been an increased mortality rate attributed to non-ADMs. Here, we provide a review of the molecular mechanisms that are responsible for the development of ADMs and non-ADMs which occur in HIV-infected individuals. It is evident that ART alone is not sufficient to fully mitigate the potential for ADMs and non-ADMs in HIV-infected individuals. To enhance the diagnosis and treatment of both HIV and malignancies, a thorough comprehension of the mechanisms driving the development of such cancers is imperative.

Lymphedema and Kaposi sarcoma: A narrative review

BACKGROUND

Kaposi sarcoma (KS), due to HHV-8 infection is classified in 4 subtypes: epidemic, endemic, HIV-related and iatrogenic essentially after organ transplant. Lymphedema is a complication of KS. We reviewed the interactions between HHV-8 infection and lymphedema according an analysis of the literature.

MAIN BODY

HHV-8 can infect different types of cells, among them a privileged tropism for lymphatic endothelial cells. It induces multi-centric endothelial proliferation leading to the occlusion of lymphatic vascular lumen. Lymphatic obstruction progressively lead to the blockage of lymphatic drainage, lymph stasis and lymphedema. Lymphedema mostly involved the lower limb affected by KS. It can then develop simultaneously or after the appearance of KS lesions but also be the first sign of KS, a long time before KS skin lesion onset. Lymphedema diagnosis is clinical and lymphoscintigraphy can confirm it if necessary. Lymphedema may be associated with active lesions of KS or non-evolutive, with only cicatricial lesions. KS should be treated according to the KS subtype, aggressive form, with local or systemic treatments associating with causal treatment, such as HIV infection or reducing immuno-suppressive drugs in transplant patients. In most of the cases, KS treatment may slightly reduce (or not) lymphedema volume which remains a chronic disease. Lymphedema management should be associated in order to reduce the volume and then stabilizing it. Low-stretch bandage, elastic garments and skin care are the cornerstone of treatment.

CONCLUSION

Lymphedema is a frequent complication of KS, and may reveal KS or occurs throughout its course. Association of KS and lymphedema must be known because lymphedema is a chronic disease affecting the quality of life. Beyond the treatment of KS, its management must be specific including a long follow-up to optimize the patient's observance required to maintain the best lymphedema control.

Glucose and mannose analogs inhibit KSHV replication by blocking N-glycosylation and inducing the unfolded protein response

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent for Kaposi's sarcoma (KS), an HIV/AIDS-associated malignancy. Effective treatments against KS remain to be developed. The sugar analog 2-deoxy- d-glucose (2-DG) is an anticancer agent that is well-tolerated and safe in patients and was recently demonstrated to be a potent antiviral, including KSHV and severe acute respiratory syndrome coronavirus 2. Because 2-DG inhibits glycolysis and N-glycosylation, identifying its molecular targets is challenging. Here we compare the antiviral effect of 2-DG with 2-fluoro-deoxy- d-glucose, a glycolysis inhibitor, and 2-deoxy-fluoro- d-mannose (2-DFM), a specific N-glycosylation inhibitor. At doses similar to those clinically achievable with 2-DG, the three drugs impair KSHV replication and virion production in iSLK.219 cells via downregulation of viral structural glycoprotein expression (K8.1 and gB), being 2-DFM the most potent KSHV inhibitor. Consistently with the higher potency of 2-DFM, we found that d-mannose rescues KSHV glycoprotein synthesis and virus production, indicating that inhibition of N-glycosylation is the main antiviral target using d-mannose competition experiments. Suppression of N-glycosylation by the sugar drugs triggers ER stress. It activates the host unfolded protein response (UPR), counteracting KSHV-induced inhibition of the protein kinase R-like endoplasmic reticulum kinase branch, particularly activating transcription factor 4 and C/EBP homologous protein expression. Finally, we demonstrate that sugar analogs induce autophagy (a prosurvival mechanism) and, thus, inhibit viral replication playing a protective role against KSHV-induced cell death, further supporting their direct antiviral effect and potential therapeutic use. Our work identifies inhibition of N-glycosylation leading to ER stress and UPR as an antienveloped virus target and sugar analogs such as 2-DG and the newly identified 2-DFM as antiviral drugs.

The immune subtypes and landscape of sarcomas

Background

Considering the molecular heterogeneity of sarcomas and their immunologically quiet character, immunotherapy (e.g., immune checkpoint inhibitors) plays a viable role in only a subset of these tumors. This study aimed to determine the immune subtypes (IMSs) of sarcomas for selecting suitable patients from an extremely heterogeneous population.

Results

By performing consensus clustering analysis of the gene expression profiles of 538 patients with sarcomas in online databases, we stratified sarcomas into three IMSs characterized by different immune cell features, tumor mutational burdens (TMBs), gene mutations, and clinical outcomes. IMS1 showed an immune “hot” and immunosuppressive phenotype, the highest frequencies of CSMD3 mutation but the lowest frequencies of HMCN1 and LAMA2 mutations; these patients had the worst progression-free survival (PFS). IMS2 was defined by a high TMB and more gene mutations, but had the lowest frequency of MND1 mutations. IMS3 displayed the highest MDN1 expression level and an immune “cold” phenotype, these patients had the worst PFS. Each subtype was associated with different expression levels of immunogenic cell death modulators and immune checkpoints. Moreover, we applied graph learning-based dimensionality reduction to the immune landscape and identified significant intra-cluster heterogeneity within each IMS. Finally, we developed and validated an immune gene signature with good prognostic performance.

Conclusions

Our results provide a conceptual framework for understanding the immunological heterogeneity of sarcomas. The identification of immune-related subtypes may facilitate optimal selection of sarcoma patients who will respond to appropriate therapeutic strategies.

Imaging More than Skin-Deep: Radiologic and Dermatologic Presentations of Systemic Disorders

Background: Cutaneous manifestations of systemic diseases are diverse and sometimes precede more serious diseases and symptomatology. Similarly, radiologic imaging plays a key role in early diagnosis and determination of the extent of systemic involvement. Simultaneous awareness of skin and imaging manifestations can help the radiologist to narrow down differential diagnosis even if imaging findings are nonspecific. Aims: To improve diagnostic accuracy and patient care, it is important that clinicians and radiologists be familiar with both cutaneous and radiologic features of various systemic disorders. This article reviews cutaneous manifestations and imaging findings of commonly encountered systemic diseases. Conclusions: Familiarity with the most disease-specific skin lesions help the radiologist pinpoint a specific diagnosis and consequently, in preventing unnecessary invasive workups and contributing to improved patient care.