Advances in dermatologic surgery

Bcl-2 phosphorylation and apoptosis activated by damaged microtubules require mTOR and are regulated by Akt

The serine/threonine kinase mTOR, the major sensor of cell growth along the PI3K/Akt pathway, can be activated by agents acting on microtubules. Damaged microtubules induce phosphorylation of the Bcl-2 protein and lower the threshold of programmed cell death, both of which are inhibited by rapamycin. In HEK293 cells expressing Akt mutants, the level of Bcl-2 phosphorylation and the threshold of apoptosis induced by taxol or by nocodazole are significantly modified. In cells expressing dominant-negative Akt (DN-Akt), Bcl-2 phosphorylation and p70S6KThr421/Ser424 phosphorylation induced by taxol or nocodazole were significantly enhanced as compared to cells expressing constitutively active Akt (CA-Akt) and inhibited by rapamycin. Moreover, DN-Akt cells were more sensitive to antitubule agents than CA-Akt cells. In nocodazole-treated HEK293 cells sorted according to cell cycle, the p70S6KThr421/Ser424 phosphorylation was associated to the G2/M fraction. More relevant, nocodazole inhibited, in a dose-response manner, mTOR phosphorylation at Ser2448. This activity, potentiated in DN-Akt cells, was not detectable in CA-Akt cells. Our results suggest that death signals originating from damaged microtubules in G2/M can compete with G1 survival pathways at the level of mTOR. These findings have implications for cancer therapy and drug resistance.

A history of dermatologic surgery in the United States

BACKGROUND

Dermatologic surgery has a long and distinguished history in the United States.

OBJECTIVE

To examine the specific contributions of American dermatologic surgeons.

METHOD

The medical literature on cutaneous reconstructive and cosmetic surgery for the last century and a half was researched.

RESULTS

Numerous American dermatologic surgeons have had a major impact on scientific and technological discoveries in cutaneous surgery. Dermatologic surgeons have been significantly involved in cutaneous surgery since the second half of the 19th century. Dermatologic surgeons have contributed many important advances to the fields of chemical peeling, cryosurgery, dermabrasion, electrosurgery, hair transplantation, soft tissue augmentation, tumescent liposuction, laser surgery, phlebology, Mohs chemosurgery, cutaneous reconstruction, wound healing, botulium toxin, blepharoplasty, and rhytidectomy.

CONCLUSION

Dermatologic surgeons in the United States have contributed significantly to the history of reconstructive and cosmetic surgery. Dermatologic surgeons have been leaders in advancing this field and are poised to continue in the future.