Immune status, strain background, and anatomic site of innoculation affect mouse papillomavirus (MmuPV1) induction of exophytic papillomas or endophytic trichoblastomas

Papillomaviruses (PVs) are able to induce papillomas, premalignant lesions, and carcinomas in a wide variety of species. PVs are classified first based on their host and tissue tropism and then their genomic diversities. A laboratory mouse papillomavirus, MmuPV1 (formerly MusPV), naturally infects NMRI-Foxn1nu/Foxn1nu (nude; T cell deficient) mice. C57BL/6J wild-type mice were not susceptible to MmuPV1 infection; however, immunocompetent, alopecic, S/RV/Cri-ba/ba (bare) mice developed small papillomas at injection sites that regressed. NMRI-Foxn1nu and B6.Cg-Foxn1nu but not NU/J-Foxn1nu mice were susceptible to MmuPV1 infection. B6 congenic strains, but not other congenic strains carrying the same allelic mutations, that lack B- and T-cells, but not B-cells alone, were susceptible to infection, indicating that mouse strain and T-cell deficiency are critical to tumor formation. Although lesions initially observed were exophytic papillomas around the muzzle, exophytic papillomas on the tail and condylomas of the vaginal lining could be induced by experimental infections. On the dorsal skin, locally invasive, poorly differentiated tumors developed with features similar to human trichoblastomas. Transcriptome analysis revealed significant differences between the normal skin in these anatomic sites and in papillomas versus trichoblastomas. The primarily dysregulated genes involved molecular pathways associated with cancer, cellular development, cellular growth and proliferation, cell morphology, and connective tissue development and function. Surprisingly, few of the genes commonly associated with basal cell carcinoma or squamous cells carcinoma were dramatically dysregulated.

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Sundberg JP, Stearns TM, Joh J, Proctor M, Ingle A, Silva KA, Dadras SS, Jenson AB, Ghim SJ