Structure-Based Discovery of Selective Histone Deacetylase 8 Degraders with Potent Anticancer Activity.

Inducing protein degradation by proteolysis targeting chimeras has gained tremendous momentum as a promising novel therapeutic strategy. Here, we report the design, synthesis, and biological characterization of highly potent proteolysis targeting chimeric small molecules targeting the epigenetic regulator histone deacetylase 8 (HDAC8). We developed potent and effective HDAC8 degraders, as exemplified by SZUH280 (16e), which effectively induced HDAC8 protein degradation and inhibited cancer cell growth even at low micromolar concentrations. Our preliminary mechanistic studies revealed that SZUH280 hampers DNA damage repair in cancer cells, promoting cellular radiosensitization. In mice, a single SZUH280 dose induced rapid and prolonged HDAC8 protein degradation in xenograft tumor tissues. Moreover, SZUH280 alone or in combination with irradiation resulted in long-lasting tumor regression in an A549 tumor mouse model. Our findings qualify a new chemical tool for HDAC8 knockdown and may lead to the development of a new class of cancer therapeutics.

Yohimbine Ameliorates Temporomandibular Joint Chondrocyte Inflammation with Suppression of NF-κB Pathway.

Local joint inflammation plays an important role in the pathogenesis of temporomandibular joint (TMJ) osteoarthrosis (TMJOA). Yohimbine, an alpha-2 adrenergic receptor antagonist, possesses anti-inflammatory properties; however, the ability of Yohimbine to protect against TMJOA-associated chondrocyte inflammation remains unclear. We conducted in vitro and in vivo analyses to investigate whether Yohimbine could ameliorate TMJOA-induced chondrocyte inflammation and to elucidate the mechanisms involved. Chondrocytes of TMJOA mice were stimulated with interleukin (IL)-1ß or noradrenaline (NE), and the resulting production of inflammation-related factors was evaluated in the presence or absence of Yohimbine. Furthermore, two TMJOA mouse models were treated with Yohimbine and the therapeutic effect was quantified. NE (10-6 M) triggered inflammatory cytokine secretion by TMJ chondrocytes, and Yohimbine suppressed IL-1ß- or NE-induced IL-6 upregulation in TMJ chondrocytes with the nuclear factor (NF)-κB pathway inhibition. Yohimbine also ameliorated cartilage destruction in the TMJOA models. Interestingly, αmpT, a tyrosine hydroxylase inhibitor, reversed the effects of Yohimbine by activating the NF-κB pathway. Collectively, these findings show that Yohimbine ameliorated TMJ chondrocyte inflammation and the suppression of NF-κB pathway contributes to this effect.

Mandibular distraction osteogenesis in the treatment of pediatric temporomandibular joint ankylosis with micrognathia and obstructive sleep apnea syndrome: A case report with 4-year follow-up.

Temporomandibular joint (TMJ) ankylosis in pediatric patients is rare and may cause severe micrognathia and obstructive sleep apnea syndrome. The present study reports on the treatment and 4-year follow-up of a pediatric patient with early-onset bilateral TMJ ankylosis and severe secondary micrognathia, as well as obstructive sleep apnea syndrome. A typical 'bird face' appearance was noted with severe mandible retrognathism and a significant convex facial profile. The treatment of this patient involved TMJ ankylosis release with condylectomy and simultaneous bilateral mandibular distraction osteogenesis, which enabled the surgeons to simultaneously reconstruct the neocondyle and correct facial malformations. Following treatment, the micrognathia was corrected and the oropharyngeal airway was significantly expanded. However, the maximal incisal opening was limited. During the 4-year follow-up, no signs of mandible retraction were noted and mouth opening increased to 17 mm (passive) compared with the inability to open that was noted immediately following surgery. A certain degree of MIO shrinkage was identified in the patient. In such cases of TMJ ankylosis, early post-operative exercise, active post-operative physiotherapy and stringent follow-up are essential to prevent post-operative shrinkage and adhesions.

Role of osteoprotegerin in the regulation of dental epithelial­mesenchymal signaling during tooth development.

Dental epithelial­mesenchymal signaling is crucial for tooth development, but the detailed mechanism is not fully understood. Using microarray analysis, it was revealed that the expression of osteoprotegerin, an important factor regulating bone remodeling, significantly increased after removal of the dental epithelium. Immunohistochemical staining revealed that osteoprotegerin expression within the dental mesenchyme was quite low during the prenatal period, but significantly increased after birth. To investigate the influence of osteoprotegerin upon tooth development, first­molar tooth germs from embryonic day 14.5 (E14.5) Chinese Kunming mice were treated with different concentrations of osteoprotegerin. It was revealed that osteoprotegerin could inhibit the expression of odontogenic markers while promoting the expression of osteogenic markers, thereby disrupting tooth morphogenesis. These findings were further supported by in vitro and in vivo cultures. Finally, quantitative reverse transcription­polymerase chain reaction and immunofluorescence studies revealed that, after osteoprotegerin treatment, the activity of the wingless/integrated (Wnt)/ß­catenin pathway increased, indicating that increased osteoprotegerin expression in prenatal tooth development could lead to uncontrolled upregulation of the Wnt/ß­catenin pathway.

Single implants in the esthetic zone: analysis of recent peri-implant soft tissue alterations and patient satisfaction. A photographic study.

PURPOSE: The appearance of the peri-implant soft tissue is a crucial factor in the success of implant therapy. However, no effective objective method exists to observe and document this factor over the long term. The aim of this clinical trial was to determine whether oral photographs can be used for peri-implant soft tissue data collection by observing peri-implant soft tissue alterations after placement of a single-tooth implant in the esthetic zone and to determine whether the pink esthetic score (PES) reflects patient satisfaction with the peri-implant soft tissue esthetic result. MATERIALS AND METHODS: Twenty-eight consecutive patients received single implants in the esthetic zone. Clinical photographs were taken to collect data on the peri-implant soft tissue at baseline (crown placement) and again 3 months later. Two observers assigned PES values to the peri-implant soft tissue in the photographs. Changes in the PES value from baseline to the 3-month follow-up were calculated. Patient satisfaction was measured using a visual analog scale (VAS) at the 3-month follow-up appointment. The correlation between the VAS and PES scores was calculated. RESULTS: The mean PES value (± SD) was 8.68 ± 2.69 at baseline and 10.37 ± 2.13 at follow-up (P < .01). VAS values ranged from 72.5 to 100. A significant correlation was found between VAS and PES values. The linear regression of patient satisfaction and PES values was significant. CONCLUSIONS: Oral photographs can be used to collect PES data on peri-implant soft tissue. The esthetic result of peri-implant soft tissue is markedly improved 3 months after restoration of the implant with a porcelain-fused-to-metal crown. The PES value generally reflects the degree of patient satisfaction with the peri-implant soft tissue esthetic result.

Simultaneous maxillomandibular distraction osteogenesis in severe progressive hemifacial atrophy with two distractors.

Progressive hemifacial atrophy is a rare disorder characterized by an acquired, idiopathic, self-limited, unilateral facial atrophy involving skin, subcutaneous tissue, fat, muscle, and bone. Symmetry and contour restoration are the main treatment challenges. Among many techniques, microvascular reconstruction has been introduced as the gold standard to correct the atrophic deformity. For some patients with severe manifestations, soft tissue reconstruction alone does not obtain the desired outcome. In this series, we used an effective method to restore the severe progressive hemifacial atrophy by simultaneous maxillomandibular distraction osteogenesis with 2 distractors. The results demonstrate an improvement in both the profile and the occlusion plane of the patients with corresponding satisfactory esthetic and functional outcomes. We conclude that the simultaneous maxillomandibular distraction osteogenesis with 2 distractors is an effective method for hemifacial atrophy and bone frame reconstruction, especially ones involved in the discrepancy of the occlusal plane.

The study of distraction osteogenesis with nitinol shape memory alloy spring controlled by infrared light.

OBJECTIVE: The objective of this study was to investigate the feasibility of distraction osteogenesis with a nitinol shape memory alloy spring controlled by infrared light. STUDY DESIGN: In each of 20 New Zealand white rabbits, a critical-size defect (15 x 10 mm) was made in the body of the mandible, and a 10 x 8-mm segmental osteotomy was performed just anterior to the defect to create a transporting disk. A heat-controlled distractor and a temperature detector were then inserted (experimental group). Nothing was attached to the other side of the mandible (control group). After a 2-day latency period, the distractor was activated by the infrared at a rate of once per day for 9 days. The contralateral side was treated with the same infrared light. Gross, radiographic, and histologic analyses and dual energy x-ray absorptiometry were performed at regular intervals. RESULTS: In the experimental group, the mandibular defect was reconstructed, whereas in the control group it was not. The histologic appearance of regenerated bone was similar to that observed with traditional distraction osteogenesis. CONCLUSION: Distraction osteogenesis using a nitinol spring controlled by infrared light is possible.

Changes of mandibular movement tracings after the correction of mandibular protrusion by bilateral sagittal split ramus osteotomy.

PURPOSE: We investigated the effects on mandibular movement tracings after the correction of mandibular protrusion by bilateral sagittal split ramus osteotomy (BSSRO). PATIENTS AND METHODS: This study was comprised of 30 control subjects and 14 mandibular protrusion patients. Mandibular movements were recorded during opening, protrusion, and laterotrusion of the jaw with the ARCUSdigma 3-dimensional mandibular kinesiograph (KaVo Dental, Biberach, Germany). The kinematic center and incisor point were used as reference points. RESULTS: The mandibular movement tracings of patients before the correction of mandibular protrusion by BSSRO were significantly different from those in subjects in the control group, whereas there were no significant differences between the mandibular movement tracings after the correction of mandibular protrusion by BSSRO and those in the control group. Furthermore, the mean biases of the condylar kinematic center in the 3-dimensional directions during the opening, protrusive, and laterotrusive movements of the jaws in the preoperative group were smaller than those in the postoperative group (P < .05), which were similar to those in the control group (P > .05). CONCLUSION: After correction by BSSRO, the mandibular movement tracings in mandibular protrusion patients will be altered to be similar to those in subjects in the control group, which we believe might support the return of mandibular functional movements in treated patients.

Retinoic acid and sodium butyrate as cell cycle regulators in the treatment of oral squamous carcinoma cells.

All-trans retinoic acid (ATRA) and sodium butyrate (SB) have shown growth-inhibitory and differentiation-inducing properties to tumor cells when used as single agents or in combination, but the exact molecular mechanism still remains to be determined. In order to determine the mechanism of the synergy in treatment with RA and SB, we evaluated the growth inhibition capability of ATRA and SB, alone or in combination, in human oral squamous carcinoma cell lines SCC-1 and SCC-9, and identified the expression of cell cycle-related genes. ATRA and SB inhibited cell growth and induced cell cycle G1 arrest. The inhibition effect was more pronounced with SB than with ATRA (p = 0.000). There were interactions between ATRA and SB (p = 0.000). Consistent with the inhibition effect and G1 arrest, ATRA and SB, alone or in combination, induced the expression of G1 phase markers cyclin-dependent kinase (CDK) 6, p21, and p27; inhibited the expression of S-G2 phase proteins CDK2; and decreased Rb phosphorylation. Cyclin D1 expression was increased in the SB- and ATRA + SB-treated groups, but inhibited in the ATRA-treated group. Cyclin B1 and cyclin E expression was slightly decreased in the SB- and ATRA + SB-treated groups, but did not change in the ATRA-treated group. These results indicate that the growth inhibition and G1 arrest of oral squamous carcinoma cells in response to ATRA and/or SB correlates with the induction of G1 phase cell cycle regulatory proteins CDK6, p21, and p27 and the inhibition of S-G2 phase cell cycle regulatory protein CDK2.

[Risk factors of fat necrosis in pectoralis major myocutaneous flaps].

OBJECTIVE: To explore the risk factors of fat necrosis in pectoralis major myocutaneous flaps. METHODS: From May 1998 to December 2005, 82 patients underwent reconstruction of oral and maxillofacial defects with pectoralis major myocutaneous flaps in our hospital. Postoperative fat necrosis of the flaps was occurred in 10 cases. Logistic regression analysis was used to investigate the risk factors. RESULTS: (1) Logistic univariate regression analysis indicated that there was a significant correlation between fat necrosis of pectoralis major myocutaneous flap and the following risk facoars: obesity, subcutaneous tissues dissection performed by electrotome, the design of skin island beyond the seventh costal cartilage and smoking. (2) Logistic multivariate regression analysis suggested that there was a significant correlation between fat necrosis of pectoralis major myocutaneous flap and obesity, subcutaneous tissues dissection performed by electrotome, the design of skin island beyond the seventh costal cartilage, whereas there was no significant correlation between fat necrosis of flap and smoking. CONCLUSIONS: Obesity, subcutaneous tissues dissection performed by electrotome and the design of skin island beyond the seventh costal cartilage were the risk factors of fat necrosis in pectoralis major myocutaneous flap.

[Correction of dento-maxillofacial deformities following cleft lip and palate repair with orthognathic surgery and orthodontics].

OBJECTIVE: To restore good occlusion and face profile, the orthognathic operation and orthodontics were used to correct the dento-maxillofacial deformities following the repair of cleft lip and palate. METHODS: 21 patients (7 males and 14 females, mean age of 20.6 years) were included in this study. Their dento-maxillofacial deformities following the repair of cleft lip and palate have been corrected in our hospital since 1996. Of them, 17 patients received pre- and postoperative orthodontic treatments. 21 cases underwent the following surgical procedures: Le Fort I osteotomy in 7 cases, multisegmental Le Fort I osteotomy in 5 cases, Le Fort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) in 4 cases, Le Fort I osteotomy and mandibular body osteotomy in 2 cases, BSSRO and genioplasty in 2 cases, BSSRO in 1 case. Rigid internal fixation was used in all patients. After multisegmental Le Fort I osteotomy, the rigid fixed palatine splint was used for 6 approximately 8 weeks. RESULTS: Osteotomy segments healed well in all cases without severe complications. 14 patients were followed-up for an average of 25.6 months. There was no evident relapse. 12 patients who received pre- and postoperative orthodontic treatments had satisfactory occlusion and face profile. CONCLUSIONS: Orthognathic operation combined with orthodontics can be used satisfactorily to correct the dento-maxillofacial deformities following cleft lip and palate repair.

[Maxilla reconstruction with the free iliac osteomuscular flap and simultaneous osseointegrated implant embeding].

OBJECTIVE: To evaluate the clinical outcome of reconstruction of maxillary defects with vascularized iliac crest flap and simultaneous osseointegrated implant embedding. METHODS: During September to October 2003, two patients with maxillary defects from tumor resection underwent microsurgical reconstruction. The free iliac osteomuscular flap transferring and simultaneous osseointegrated implant embedding were performed to repair the defects. Three months after the reconstructive surgery, an abutment operation was preformed and denture was applied in both cases. RESULTS: The flaps survived well. Postoperative follow-up for 8 to 9 months showed that the patients obtained good zygomaxillary appearance, normal occlusion, and satisfactory pronunciation, without oronasal fistula or other serious complications. CONCLUSIONS: The free iliac crest osteomuscular flap with simultaneous osseointegrated implant embedding is an ideal, effective and cosmetically acceptable method for maxilla reconstruction.

[Expression of p15 and p16 proteins in tongue squamous cell carcinoma and their significances].

BACKGROUND & OBJECTIVE: Abnormal expression of p15 and p16 were commonly found in many kinds of primary tumors, but the possible correlation between p15 and p16 abnormalities and tongue neoplasms is still unknown. This study was designed to investigate the expression of p15 and p16 proteins and their possible correlation with clinicopathology and prognosis of tongue squamous cell carcinoma (TSCC). METHODS: The expression of p15 and p16 were detected by immunohistochemistry (ultra-sensitive SP method) and the results were analyzed quantitatively by imagine cytometry in 45 cases of TSCC and 10 cases of normal tongue tissues, thereafter, the results were analyzed with clinicopathological parameters and survival time. RESULTS: Both p15 and p16 proteins were expressed in squamous epithelia of the normal tongue tissues. The negative expression rates of p15 and p16 protein in TSCC were 46.7%(21/45) and 66.7%(30/45), respectively. 80%(12/15) of the p16 positive cases accompanied with p15 positive staining. However, 85.7%(18/21) of the cases with p15 deletion exhibited p16 negative expression. Most of the cases with both p15 and p16 co-deletion were found in stage III and IV (16/18). The expression rates of p15 and/or p16 in stage I, II were significantly higher than those in stage III, IV (P< 0.05), while p15 and/or p16 expression rates in node-positive groups were much lower than those in node-negative groups (P< 0.01). p15 deletion, or both p15 and p16 co-deletion group, also had a decreased 3-year survival rate (P< 0.05). CONCLUSION: The expression of p15 and p16 protein are closely associated with clinical stages and cervical lymph node metastasis of TSCC. p15 deletion, or both p15 and p16 co-deletion in TSCC can also predict a poor prognosis. p15 and p16 expression can be used as parameters for evaluating clinical stages and metastatic potential as well as prognosis of TSCC.

[The effects of insulin-like growth factor-II on the proliferation of osteoblast-like cells in vitro].

OBJECTIVE: To seek for the appropriate concentration, at which IGF-II can exerts its strong effects on postirradiation proliferation, physiological function and differentiation of the rat's osteoblast-like cells (ROB). METHODS: The osteoblast-like cells used were isolated from the calvariae of neonatal (one-day-old) SD rats by sequential enzymatic digestion. The third passages of the cells were irradiated with gamma-ray from a (60)Co source at the doses of 100, 400, 600, and 900 cGy. The medium was changed immediately after irradiation and 5 concentrations of IGF-II, i.e., 0, 0.1, 1.0, 10.0, and 100.0 microgram/L were added. 6 days after radiation (9 days in culture), the examination, or the measurement of relative cell number, was carried out. RESULTS: Radiation inhibited the ROB, even lethally. IGF-II completely counteracted the inhibitory effects when the cells were exposed to the radiation at lower dose (100 cGy), and partially when at higher dose (400 cGy). But after the radiation at much higher dose as 900 cGy, the damages were irreversible, even with the existence of this growth factor. CONCLUSIONS: At least a portion of effective recovery of postirradiation damages may be due to IGF-II-induced radioresistance. Incubation with IGF-II can increase radioresistance or repair of radiation-induced cells damages. However, this effect depends on the dose of radiation.