There's very little on Spiral. They've been mentioned here a few times:
https://www.tinnitustalk.com/posts/241986
https://www.tinnitustalk.com/posts/241988
There are a couple of abstracts from poster presentations at conferences. From what I can tell, the authors do not appear to be employees of Loop or Spiral Therapeutics, but the poster abstracts do refer to LPT99.
Title:
Inhibition of APAF-1 with LPT99 prevents cisplatin-induced hearing loss
Abstract:
Hearing loss is a common severe adverse effect of chemotherapy with platinum agents, especially cisplatin. Cisplatin induces the depletion of glutathione and antioxidant enzymes, leading to accumulation of reactive oxygen species in the cochlea, which trigger the intrinsic apoptotic pathway in hair cells. The apoptosis protease-activating factor-1 (APAF-1) binds to cytochrome c to form the apoptosome, which recruit procaspase-9 and activates effector caspases. APAF-1 inhibition has been previously validated as therapeutic strategy for the prevention of unwanted apoptosis. Here we evaluate the in vivo therapeutic effect of LPT99, a second generation APAF-1 inhibitor with good cochlear permeability, in the prevention of cisplatin induced-hearing loss in rats. LPT99 (50-200 mM in vehicle) was administered by transtympanic surgery in young male Wistar rats. Ototoxicity was induced immediately after by intraperitoneal slow infusion of cisplatin (10 mg/kg). Hearing was evaluated by registering the auditory brainstem response (ABR) to click and pure tones, before and 3 days after cisplatin administration. Finally, rats were euthanized and the cochleae dissected for total RNA extraction and gene expression or histology. LPT99 treatment of rats attenuated the threshold shifts induced by cisplatin after 3 days of its administration when compared to the vehicle-treated rats. Thresholds of tone frequencies of 20, 28 and 40 kHz were significantly lower than in the cisplatin group. This protective effect was dose-dependent, showing 100 μM dose the best profile. In addition, LPT99 diminished the alterations in ABR peak latencies and amplitudes induced by cisplatin administration. The expression of p53, Il1α and Kim-1 was reduced in LPT99-treated cochleae, suggesting that LPT99 prevents inflammation and apoptosis. In conclusion, transtympanic administration of LPT99 protects from cisplatin-induced hearing loss in rats, confirming APAF-1 as a valid pharmacological target and postulating LPT99 as a potential first in class drug candidate.
(
https://webcache.googleusercontent....handle/10261/154222+&cd=8&hl=en&ct=clnk&gl=us)
Title:
Inhibition of APAF-1 with LPT99 prevents cisplatin-induced apoptosis in HEI-OC1 auditory cells
Abstract:
HEI-OC1 (House Ear Institute - organ of Corti 1) is an epithelial otic cell line that was derived by Kalinec et al. (2003) from the cochlea of a transgenic mouse called ImmortomouseTM, which harbors a temperature-sensitive mutant of the SV40 large T antigen. The modulation of culture conditions allows the progression of the progenitor cells to a differentiated hair cell-like with a phenotype similar to that of the adult organ of Corti. One the most interesting characteristic of these cells is their sensitivity to ototoxic drugs such as aminoglycoside antibiotics or antineoplastic agents as cisplatin, which can cause sensorineural hearing loss. Cisplatin is a highly effective chemotherapeutic agent, but it has significant ototoxic side effects. Apoptosis is an important mechanism of cochlear hair cell loss following exposure to cisplatin. The present study examined the effects of LPT99, a second generation of APAF-1 inhibitors on cisplatin-induced apoptosis. Viability and growth rate of HEI-OC1 cells were determined using a crystal violet based staining method and the activation of Caspase-3, a biochemical marker for apoptosis cell death was evaluated with immunocytochemistry. We observed a dose-dependent decrease in cell viability after challenge with cisplatin (0-5 μg/mL); however survival rate increased in the presence of 1 μM LPT99. According, cells treated with cisplatin showed an IC50 of 4.47±1.94 μg/mL, which increased dramatically to 10.51 ± 3 μg/mL in the presence of LPT99. In addition, immunofluorescence studies suggest that the activity of Caspase-3 after cisplatin treatment decreased in the presence of LPT99. These results suggest that LPT99 protected the cells HEI-OC1 against cisplatin-induced apoptosis by inhibiting of APAF-1.
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https://webcache.googleusercontent....andle/10261/154180+&cd=13&hl=en&ct=clnk&gl=us)