miR-34a-5p inhibits the malignant progression of KSHV-infected SH-SY5Y cells by targeting c-fos

Background

We aimed to investigate the effects of miR-34a-5p on c-fos regulation mediating the malignant behaviors of SH-SY5Y cells infected with Kaposi's sarcoma-associated herpesvirus (KSHV).

Methods

The KSHV-infected (SK-RG) and uninfected SH-SY5Y parent cells were compared for differentially expressed miRNAs using transcriptome sequencing. Then miR-34a-5p was upregulated in SK-RG cells by the miRNA mimics transfection. Cell proliferation ability was determined by MTT and plate clone assays. The cell cycle was assessed by flow cytometry analysis, and CDK4, CDK6, cyclin D1 levels were determined by Western blot analysis. The migration behavior was detected by wound healing and transwell assays. The protein levels of MMP2 and MMP9 were measured by Western blot analysis. The regulation of c-fos by miR-34a-5p was detected by the dual-luciferase reporter gene assay. Rescue assays were carried out by upregulating c-fos in miR-34a-5p-overexpressing SK-RG cells. KSHV DNA copy numbers and relative virus gene expressions were detected. Xenograft tumor experiments and immunohistochemistry assays were further used to detect the effects of miR-34a-5p.

Results

miR-34a-5p was lower in SK-RG cells. Restoration of miR-34a-5p decreased cell proliferation and migration, leading to a G1 cell cycle arrest and down-regulation of CDK4/6, cyclin D1, MMP2, MMP9. KSHV copy number and expression of virus gene including latency-associated nuclear antigen (LANA), replication and transcription activator (RTA), open reading frame (K8.1), and KSHV G protein-coupled receptor (v-GPCR) were also reduced. Furthermore, c-fos is the target of miR-34a-5p, while enhanced c-fos weakened cellular behaviors of miR-34a-5p-overexpressing cells. Xenograft experiments and immunohistochemistry assays showed that miR-34a-5p inhibited tumor growth and virus gene expression.

Conclusion

Upregulated miR-34a-5p in KSHV-infected SH-SY5Y cells suppressed cell proliferation and migration through down-regulating c-fos. miR-34a-5p was a candidate molecular drug for KSHV-infected neuronal cells.

Novel Virus Related to Kaposi's Sarcoma-Associated Herpesvirus from Colobus Monkey

We determined the complete genome sequence of a virus isolated from a mantled guereza that died of primary effusion lymphoma. The virus is closely related to Kaposi’s sarcoma–associated herpesvirus (KSHV) but lacks some genes implicated in KSHV pathogenesis. This finding may help determine how KSHV causes primary effusion lymphoma in humans.

The Contribution of Kaposi's Sarcoma-Associated Herpesvirus to Mortality in Hospitalized Human Immunodeficiency Virus-Infected Patients Being Investigated for Tuberculosis in South Africa

BACKGROUND

Despite increasing numbers of human immunodeficiency virus (HIV)-infected South Africans receiving antiretroviral therapy (ART), tuberculosis (TB) remains the leading cause of mortality. Approximately 25% of patients treated for TB have microbiologically unconfirmed diagnoses. We assessed whether elevated Kaposi's sarcoma-associated herpesvirus (KSHV) viral load (VL) contributes to mortality in hospitalized HIV-infected patients investigated for TB.

METHODS

Six hundred eighty-two HIV-infected patients admitted to Khayelitsha Hospital, South Africa, were recruited, investigated for TB, and followed for 12 weeks. KSHV serostatus, peripheral blood KSHV-VL, and KSHV-associated clinical correlates were evaluated.

RESULTS

Median CD4 count was 62 (range, 0-526) cells/μL; KSHV seropositivity was 30.7% (95% confidence interval [CI], 27%-34%); 5.8% had detectable KSHV-VL (median, 199.1 [range, 13.4-2.2 × 106] copies/106 cells); 22% died. Elevated KSHV-VL was associated with mortality (adjusted odds ratio, 6.5 [95% CI, 1.3-32.4]) in patients without TB or other microbiologically confirmed coinfections (n = 159). Six patients had "possible KSHV-inflammatory cytokine syndrome" (KICS): 5 died, representing significantly worse survival (P < .0001), and 1 patient was diagnosed with KSHV-associated multicentric Castleman disease at autopsy.

CONCLUSIONS

Given the association of mortality with elevated KSHV-VL in critically ill HIV-infected patients with suspected but not microbiologically confirmed TB, KSHV-VL and KICS criteria may guide diagnostic and therapeutic evaluation.

Association of Household Food- and Drink-Sharing Practices With Human Herpesvirus 8 Seroconversion in a Cohort of Zambian Children

Background

Human herpesvirus 8 (HHV-8) infection occurs in early childhood and is associated with human immunodeficiency virus type 1 (HIV-1) infection and risk for Kaposi sarcoma, but behaviors associated with HHV-8 transmission are not well described.

Methods

We enrolled and followed a prospective cohort of 270 children and their household members to investigate risk factors for HHV-8 transmission in Lusaka, Zambia.

Results

We report an incidence of 30.07 seroconversions per 100 child-years. Independent risk factors for HHV-8 incident infection included having a child who shared utensils with a primary caregiver (hazards ratio [HR], 2.33; 95% confidence interval [CI], 1.49-7.14), having an increasing number of HHV-8-infected household members (HR, 1.27; 95% CI, 1.09-2.79), and having ≥5 siblings/children in the household (HR, 2.24; 95% CI, 1.03-4.88). Playing with >5 children a day was protective against infection (HR, 0.54; 95% CI, .33-0.89), as was increasing child age (HR, 0.96; 95% CI, .93-.99).

Conclusions

This is the first study to find a temporal association between limited child feeding behaviors and risk for HHV-8 infection. Child food- and drink-sharing behaviors should be included in efforts to minimize HHV-8 transmission, and households with a large number of siblings should receive additional counseling as childhood infections occur in the home context.

Establishing and characterizing a new primary effusion lymphoma cell line harboring Kaposi's sarcoma-associated herpesvirus

BACKGROUND

Primary effusion lymphoma is a rare distinct large B-cell neoplasm that is associated with Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Over recent years, 9 KSHV-positive/Epstein-Barr virus (EBV)-negative PEL cell lines have been established.

METHODS

Tumor cells were collected from the pleural effusion of a 49-year-old male with AIDS. Cells were grown in RPMI1640 culture medium supplemented with 10 % fetus bovine serum. Single cell cloning was performed successfully by a limiting dilution method in a 96-well plate. The cell line obtained was designated SPEL.

RESULTS

SPEL cells showed gourd-shaped morphology with a polarized nucleus, expressing CD38, CD138, and Blimp-1, but not B cell markers such as CD19 and CD20. Polymerase chain reaction analysis revealed that SPEL cells were positive for KSHV but negative for EBV. Tetradecanoylphorbol acetate induced expression of KSHV lytic proteins and the production of KSHV particles in SPEL cells. Subcutaneous inoculation of SPEL cells into severe combined immunodeficiency mice resulted in the formation of solid tumors. Next-generation sequencing revealed the 138 kbp genome sequence of KSHV in SPEL cells. Suberic bishydroxamate, a histone deacetylase inhibitor, induced the expression of KSHV-encoded lytic proteins and cell death in SPEL cells.

CONCLUSIONS

A new KSHV-positive and EBV-negative PEL cell line, SPEL was established. This cell line may contribute to furthering our understanding of the pathogenesis of PEL and KSHV infection.