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The cell dynamics and cell origin for anagen hair follicle (HF) repair following chemotherapeutic injury are unclear. We first mapped the HF response to cyclophosphamide (CYP) at natural anagen VI in mice. We found that 30‐60 mg/kg of CYP leads to dose‐dependent HF dystrophy that was spontaneously repaired with anagen resumption, while 120 mg/kg of CYP prematurely induced catagen/telogen entry. To explore how anagen HF repair is achieved in the dystrophic anagen pathway, we analysed the cell dynamics at 30 mg/kg of CYP. Hair bulbs first shrunk due to matrix cell apoptosis associated with DNA double‐strand breaks. DNA damage was repaired, and ordered hair bulb structures were restored within 96 hours. Bulge stem cells did not undergo apoptosis nor proliferation. K5+ basal lower proximal cup cells and outer root sheath cells quickly replenished the cells in the germinative zone and regenerated the concentric layered structures of the lower HF segment. Therefore, anagen HFs are able to summon extra‐bulge progenitor cells in close proximity to the damaged matrix for quick repair after CYP injury. [ABSTRACT FROM AUTHOR]

Neurofibromatosis type 1 (NF1) is an inherited neurological disorder. Approximately 5–13% of NF1 patients may develop a malignant peripheral nerve sheath tumor (MPNST), which is a neurofibrosarcoma transformed from the plexiform neurofibroma or schwannoma. Given the large size and easy metastasis of MPNST, it remains difficult to be cured by either surgical or conventional chemotherapy. In this study, we investigated the possibility of combining photodynamic therapy (PDT) and chemotherapy to treat MPNST by using a dual-effect liposome (named as PL-cDDP-Ce6), in which a chemotherapeutic agent, cisplatin (cDDP), and photosensitizer, chlorine e6 (Ce6) were encapsulated in the same carrier. The cytotoxic effect of PL-cDDP-Ce6 against MPNST cells was significantly higher than cells treated with liposomal cDDP or Ce6 alone or in combination after light irradiation. Treatment with the dual-effect liposomes in mice bearing xenograft MPNST tumor reveals a significant increase in survival rate compared to those treated with liposomal cDDP and Ce6 in combination. Moreover, there is no weight loss or derangements of serum biochemistry. In conclusion, this study demonstrates the clinical potential and advantage of using this liposomal drug for the treatment of MPNST. [ABSTRACT FROM AUTHOR]