Prognostic model using postoperative normalization of C-reactive protein levels in patients with upper tract urothelial carcinoma treated with radical nephroureterectomy.

INTRODUCTION: To improve the prediction of outcomes in patients who will undergo radical nephroureterectomy (RN U) for upper tract urothelial carcinoma (UTUC), we investigated the preoperative prognostic factors and developed a risk classification model. METHODS: A total of 144 patients who underwent RNU with history of neither neoadjuvant nor adjuvant chemotherapy between 2008 and 2022 were retrospectively reviewed. Associations between perioperative/clinicopathologic factors and outcomes, including cancer-specific survival (CSS), were assessed. We specifically focused on preoperative serum C-reactive protein (CRP) and its postoperative normalization. RESULTS: Non-normalization of postoperative serum CRP level and pathologic T3 stage were identified as independent predictive factors of shorter CSS in univariate and multivariate analysis (p=0.0150 and 0.0037, hazard ratio: 3.628 and 4.470, respectively). We classified the patients into three groups using these factors and found that five-year CSS was 88%, 42.5%, and 0% in the low-risk group (zero factors), intermediate-risk group (one factor), and high-risk group (two factors), respectively (p<0.0001). CONCLUSIONS: Non-normalization of postoperative serum CRP level and pathologic T stage were identified as independent postoperative prognostic factors in patients with UTUC who underwent RNU. These factors can stratify three prognostic groups and may help urologists in clinical decision-making for adjuvant therapy.

Multidisciplinary treatment for small cell carcinoma of the bladder: a case report.

Small cell carcinoma (SCC) of the urinary bladder is a rare and highly aggressive subtype of bladder cancer. Most cases are diagnosed at advanced stages, and its therapeutic strategy remains unestablished. Here, we report a case of bladder SCC in which multidisciplinary treatment has resulted in relatively long-term survival. A 68-year-old man presented with gross hematuria. A cystoscopy revealed an invasive bladder tumor. A transurethral resection of bladder tumor (TURBT) was performed, and the pathological diagnosis was SCC. After systemic chemotherapy using etoposide and carboplatin and subsequent TURBT, a radical cystectomy and ileal conduit were performed. Three months postoperatively, the patient had a recurrence in the para-aortic lymph node. Systemic combination chemotherapy with carboplatin plus irinotecan (CBDCA + CPT-11) was administered, followed by amrubicin and an immune checkpoint inhibitor. In addition to this treatment, radiation therapy for the metastatic region led to the reduction of pain and shrinkage of the metastatic lesion. The patient survived for 2 years after the initial diagnosis. Our report indicates that multidisciplinary treatment can be effective for SCC of the bladder, and a therapeutic strategy including the identification of novel biomarkers should be established.

Ureteral obstruction following transurethral resection of bladder cancer within the Hutch's diverticulum.

Here, we report a rare case of bladder cancer within the left congenital periureteral diverticulum, termed the Hutch's diverticulum. Following transurethral resection of the bladder tumor, repeated pyelonephritis was caused by stricture of the diverticulum orifice and ureter. We attempted transurethral dilation and ureteral stenting, but the obstruction did not improve. The patient's renal dysfunction showed gradual progression due to recurrent left pyelonephritis as well as the ureteral obstruction. Therefore, we finally performed a partial cystectomy, involving stricture and ureteral reimplantation. No tumor recurrence was observed over 39 months, and renal dysfunction did not progress following partial cystectomy.

Impact of adjuvant chemotherapy for patients with locally advanced upper tract urothelial carcinoma in real-world clinical practice.

INTRODUCTION: The impact of adjuvant chemotherapy (ACT) using regimens including gemcitabine and platinum on the improvement of the prognosis of patients with locally advanced upper tract urothelial carcinoma (UTUC) has been recently demonstrated. This study aimed to determine the utility of ACT for patients with locally advanced UTUC in real-world clinical practice and the differences in efficacy among regimens. METHODS: Of 206 UTUC patients who underwent radical nephroureterectomy, 78 were pathologically diagnosed as T3 or higher and/or had pathologically identified lymph node metastasis; 36 in the ACT group and 42 in the non-ACT group were evaluated for patient background, recurrence, and prognosis. In the ACT group, either cisplatin (GC group, 12 cases) or carboplatin (GCa group, 24 cases) was administered as the platinum agent to be combined with gemcitabine. RESULT: The median patient age in the ACT group and that in the non-ACT group was 71 and 79 years, respectively (p<0.0001). There was no significant difference between these two groups in terms of other patient parameters. The two- and five-year cancer-specific survival (CSS ) and the two- and five-year disease-free survival (DFS) for the ACT group were 81.7%, 66.0%, 60.6%, and 56.6%, respectively, and for the non-ACT group were 68.4%, 40.5%, 42.8%, and 29.3%, respectively (p=0.0399 for CSS and p=0.0814 for DFS). There was no significant difference in CSS and DFS between the GC group and GCa group (p=0.9846 and p=0.9389, respectively). CONCLUSIONS: In real-world clinical practice in Japan, UTUC patients who receive ACT after radical nephroureterectomy may be expected to have better cancer control than those who do not receive ACT.

Peritoneal and pulmonary tuberculosis following intravesical administration of Bacillus Calmette-Guérin for bladder cancer.

We report a rare case of peritoneal and pulmonary tuberculosis after intravesical instillation of Bacillus Calmette-Guérin (BCG). A 76-year-old man diagnosed as high-grade urothelial carcinoma (UC) with carcinoma in situ (CIS) was treated with intravesical BCG instillation and transurethral resection of bladder tumor (TUR-BT). Three months later, TUR-BT for recurrent tumors and multiple site biopsy of bladder mucosa were performed. During TUR-BT, near perforation in the posterior wall was observed, and was disappeared after observation with urethral catheterization for 1 week. Two weeks later, he was admitted with a complaint of abdominal distention, and a computed tomography (CT) showed ascites. One week later, CT showed pleural effusion and worsening of ascites. Drainage of pleural effusion and ascites puncture was performed, and elevated adenosine deaminase (ADA) and lymphocytes count were subsequently found. In laparoscopic examination, numerous white nodules were observed in the peritoneum and omentum, and Langhans giant cells were pathologically identified in biopsy specimens. Mycobacterium culture confirmed Mycobacterium tuberculosis complex. The patient was then diagnosed with pulmonary and peritoneal tuberculosis. Anti-tuberculous agents consisting of isoniazid (INH), rifampicin (RFP), and ethambutol (EB) were administered. Six months later, a CT scan showed no evidence of pleural effusion or ascites. There has been no recurrence of either urothelial cancer or tuberculosis during follow-up for 2 years.

p130Cas is required for androgen-dependent postnatal development regulation of submandibular glands.

Salivary glands develop through epithelial-mesenchymal interactions and are formed through repeated branching. The Crk-associated substrate protein (p130Cas) serves as an adapter that forms a complex with various proteins via integrin and growth factor signaling, with important regulatory roles in several essential cellular processes. We found that p130Cas is expressed in ductal epithelial cells of the submandibular gland (SMG). We generated epithelial tissue-specific p130Cas-deficient (p130CasΔepi-) mice and aimed to investigate the physiological role of p130Cas in the postnatal development of salivary glands. Histological analysis showed immature development of granular convoluted tubules (GCT) of the SMG in male p130CasΔepi- mice. Immunofluorescence staining showed that nuclear-localized androgen receptors (AR) were specifically decreased in GCT cells in p130CasΔepi- mice. Furthermore, epidermal growth factor-positive secretory granules contained in GCT cells were significantly reduced in p130CasΔepi- mice with downregulated AR signaling. GCTs lacking p130Cas showed reduced numbers and size of secretory granules, disrupted subcellular localization of the cis-Golgi matrix protein GM130, and sparse endoplasmic reticulum membranes in GCT cells. These results suggest that p130Cas plays a crucial role in androgen-dependent GCT development accompanied with ER-Golgi network formation in SMG by regulating the AR signaling.

Deletion of epithelial cell-specific p130Cas impairs the maturation stage of amelogenesis.

Amelogenesis consists of secretory, transition, maturation, and post-maturation stages, and the morphological changes of ameloblasts at each stage are closely related to their function. p130 Crk-associated substrate (Cas) is a scaffold protein that modulates essential cellular processes, including cell adhesion, cytoskeletal changes, and polarization. The expression of p130Cas was observed from the secretory stage to the maturation stage in ameloblasts. Epithelial cell-specific p130Cas-deficient (p130CasΔepi-) mice exhibited enamel hypomineralization with chalk-like white mandibular incisors in young mice and attrition in aged mouse molars. A micro-computed tomography analysis and Vickers micro-hardness testing showed thinner enamel, lower enamel mineral density and hardness in p130CasΔepi- mice in comparison to p130Casflox/flox mice. Scanning electron microscopy, and an energy dispersive X-ray spectroscopy analysis indicated the disturbance of the enamel rod structure and lower Ca and P contents in p130CasΔepi- mice, respectively. The disorganized arrangement of ameloblasts, especially in the maturation stage, was observed in p130CasΔepi- mice. Furthermore, expression levels of enamel matrix proteins, such as amelogenin and ameloblastin in the secretory stage, and functional markers, such as alkaline phosphatase and iron accumulation, and Na+/Ca2++K+-exchanger in the maturation stage were reduced in p130CasΔepi- mice. These findings suggest that p130Cas plays important roles in amelogenesis (197 words).

The unique function of p130Cas in regulating the bone metabolism.

p130 Crk-associated substrate (Cas) functions as an adapter protein and plays important roles in certain cell functions, such as cell proliferation, spreading, migration, and invasion. Furthermore, it has recently been reported to have a new function as a mechanosensor. Since bone is a tissue that is constantly under gravity, it is exposed to mechanical stress. Mechanical unloading, such as in a microgravity environment in space or during bed rest, leads to a decrease in bone mass because of the suppression of bone formation and the stimulation of bone resorption. Osteoclasts are multinucleated bone-resorbing giant cells that recognize bone and then form a ruffled border in the resorption lacuna. p130Cas is a molecule located downstream of c-Src that is important for the formation of a ruffled border in osteoclasts. Indeed, osteoclast-specific p130Cas-deficient mice exhibit osteopetrosis due to osteoclast dysfunction, similar to c-Src-deficient mice. Osteoblasts subjected to mechanical stress induce both the phosphorylation of p130Cas and osteoblast differentiation. In osteocytes, mechanical stress regulates bone mass by shuttling p130Cas between the cytoplasm and nucleus. Oral squamous cell carcinoma (OSCC) cells express p130Cas more strongly than epithelial cells in normal tissues. The knockdown of p130Cas in OSCC cells suppressed the cell growth, the expression of receptor activator of NF-κB ligand, which induces osteoclast formation, and bone invasion by OSCC. Taken together, these findings suggest that p130Cas might be a novel therapeutic target molecule in bone diseases, such as osteoporosis, rheumatoid arthritis, bone loss due to bed rest, and bone invasion and metastasis of cancer.

Real-world evidence for long-term safety and effectiveness of ipragliflozin in treatment-naïve versus non-naïve Japanese patients with type 2 diabetes mellitus: subgroup analysis of a 3-year post-marketing surveillance study (STELLA-LONG TERM).

BACKGROUND: STELLA-LONG TERM was a 3-year post-marketing surveillance study that evaluated the long-term safety and effectiveness of ipragliflozin in Japanese patients with type 2 diabetes mellitus (T2DM). This subgroup analysis examined the safety and effectiveness of ipragliflozin in treatment-naïve and non-naïve patients. MATERIALS AND METHODS: Patients were stratified into two subgroups: treatment-naïve (patients who had not received any antidiabetic drugs before starting ipragliflozin monotherapy) and non-naïve (all other patients). Patients who had added or switched antidiabetic drugs during follow-up were excluded from the analysis from that point. The incidence of adverse drug reactions (ADRs) and changes from baseline in glycosylated hemoglobin (HbA1c), body weight, fasting plasma glucose (FPG) and laboratory parameters were assessed. RESULTS: Of the 11,051 patients in the safety analysis set, 1980 patients (17.92%) were treatment-naïve and 9071 (82.08%) were non-naïve. In the safety analysis set, treatment-naïve patients reported significantly lower incidences of ADRs (10.81% vs 20.87%; p < 0.001) and serious ADRs (0.86% vs 2.09%; p < 0.001) compared with non-naïve patients, as well as significantly lower incidences of polyuria/pollakiuria, volume depletion-related events, skin complications and renal disorders. In the effectiveness analysis, sustained and significant reductions from baseline to 36 months were observed in HbA1c, FPG and body weight in both treatment-naïve and non-naïve patients (all p < 0.001 vs baseline). CONCLUSIONS: Over 3 years, ipragliflozin was better tolerated in treatment-naive than in non-naive Japanese patients with T2DM and had similar efficacy in these populations. Therefore, ipragliflozin is a useful first-line treatment option for patients with T2DM. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02479399. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13340-021-00501-w.

Systemic inflammatory responses after orthopedic surgery in patients with rheumatoid arthritis treated with tofacitinib.

OBJECTIVE: To investigate the acute phase response to surgical stress in patients with rheumatoid arthritis (RA) treated with tofacitinib, a Janus kinase (JAK) inhibitor. METHODS: A retrospective matched pair analysis of 34 patients treated with tofacitinib and 34 patients treated with conventional disease-modifying anti-rheumatic drugs (csDMARDs) was performed. Patients were matched for age, sex, and type of surgery; body temperature, C-reactive protein (CRP) level, and white blood cell (WBC) count, neutrophil count, and lymphocyte count were compared between the tofacitinib and csDMARDs groups within 2 weeks after orthopedic surgery. Postoperative complications within 90 days were also assessed. RESULTS: No surgical site infection or delayed wound healing was observed in the tofacitinib group; whereas, one case of superficial infection was noted in the csDMARDs group. A similar postoperative increase in body temperature and CRP level was observed in both the groups. Postoperatively, the tofacitinib group showed an increase in WBC and neutrophils counts and a decrease in lymphocyte count, unlike the csDMARDs group. In contrast to two patients (2.6%) in the csDMARDs group, seven patients (20.6%) in the tofacitinib group had lymphocyte counts below 500 cells/µL within 2 weeks postoperatively. CONCLUSION: Tofacitinib did not suppress postoperative increase in body temperature and CRP level. Because of the postoperative decrease in lymphocyte count in patients treated with tofacitinib, the timing for resuming tofacitinib treatment after surgery should be carefully considered. Key Points • This study is the first to report the complications and systemic inflammatory responses after orthopedic surgery in patients treated with tofacitinib in comparison with matched pairs treated with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) • While tofacitinib does not suppress postoperative increase in body temperature and CRP level, the postoperative decrease in lymphocyte count in patients treated with tofacitinib is significant compared with patients treated with csDMARDs • Attention should be paid to a reduced lymphocyte count when to resume tofacitinib after surgery.

Effect of ipragliflozin on liver function in Japanese type 2 diabetes mellitus patients: subgroup analysis of a 3-year post-marketing surveillance study (STELLA-LONG TERM).

The STELLA-LONG TERM prospective post-marketing surveillance study assessed ipragliflozin in Japanese patients with type 2 diabetes mellitus (T2DM). This subgroup analysis of patients with liver impairment used the final 3-year results. Data on patients, adverse drug reactions (ADRs), and changes in glycemic parameters and liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], gamma-glutamyl transpeptidase [γ-GTP] and alkaline phosphatase [ALP]) were collected, and the fatty liver index (FLI) was calculated. In the effectiveness analysis (n = 8,763), baseline liver function was normal in 2,605 patients (ALT <31/<21 U/L [men/women]) and abnormal in 3,277 (ALT ≥31/≥21 U/L). The abnormal liver function group had higher mean body weight and BMI than the normal liver function group (p < 0.001). In the safety analysis (n = 11,051), urinary tract infections, genital infections and hepatic disorders were more common in the abnormal than normal liver function group (2.25% vs. 1.07%; 1.78% vs. 1.14% and 1.85% vs. 1.01%). In the abnormal liver function group, there were significant (p < 0.001) decreases from baseline at 36 months in AST and ALT (from 38.8 and 53.7 U/L to 29.3 and 37.7 U/L, respectively), γ-GTP (from 75.4 to 51.7 U/L) and ALP (from 254.8 to 234.5 U/L), which were greater than in the normal liver function group. FLI reductions at 36 months were significant (p < 0.001) in subgroups with baseline FLI of ≥30 or ≥60. In conclusion, ipragliflozin improved liver function over 3 years in patients with impaired liver function, although ADRs occurred more frequently than in the normal liver function group.

Safety and Effectiveness of Ipragliflozin in Elderly Versus Non-elderly Japanese Patients with Type 2 Diabetes: Subgroup Analysis of STELLA-LONG TERM.

INTRODUCTION: STELLA-LONG TERM is a post-marketing surveillance study evaluating the safety and effectiveness of ipragliflozin in Japanese patients with type 2 diabetes mellitus. METHODS: Patients were classified by age at ipragliflozin initiation (< 65 and ≥ 65 years), and elderly patients were subclassified by baseline body mass index (BMI) < 25.0 or ≥ 25.0 kg/m2. Incidence of adverse drug reactions (ADRs) and effectiveness were evaluated over 3 years. RESULTS: Among 11,051 patients, 7894 (71.4%) were aged < 65 years and 3157 (28.6%) ≥ 65 years. The 3-year ADR incidence was similar in patients aged ≥ 65 (19.04%) and < 65 years (19.36%; P = 0.701). Serious ADRs were more frequent in the subgroup ≥ 65 years (2.79% vs 1.55%; P < 0.001). In terms of ADRs of special interest, a significantly greater proportion of elderly patients had skin complications (2.22% vs 1.62%, P = 0.033), renal disorders (2.28% vs 1.51%, P = 0.005), hypoglycemia (0.73% vs 0.43%, P = 0.048), or malignant tumors (1.01% vs 0.24%, P < 0.001), while the incidence of polyuria/pollakiuria (5.97% vs 4.47%, P = 0.002) and hepatic disorders (1.39% vs 0.73%, P = 0.004) was significantly higher in non-elderly than elderly patients. In patients aged ≥ 65 years, the incidence of ADRs was higher when baseline BMI was ≥ 25 kg/m2 versus < 25 kg/m2 (24.40% vs 17.68%; P < 0.001). Glycosylated hemoglobin, fasting blood glucose, and body weight significantly decreased from baseline in both age groups at each evaluation up to 3 years (all P < 0.001). CONCLUSIONS: Ipragliflozin was well tolerated and effective for 3 years in routine clinical use in elderly and non-elderly patients, although elderly patients had a higher rate of serious ADRs. No new safety concerns were identified. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02479399.

Safety and effectiveness of ipragliflozin in Japanese patients with type 2 diabetes mellitus and impaired renal function: subgroup analysis of a 3-year post-marketing surveillance study (STELLA-LONG TERM).

STELLA-LONG TERM, a 3-year post-marketing surveillance study, evaluated the safety and effectiveness of the sodium-glucose cotransporter 2 inhibitor ipragliflozin in Japanese type 2 diabetes mellitus (T2DM) patients. Final results in the safety (n = 6697) and effectiveness populations (n = 5625) were analyzed by stratifying patients by baseline estimated glomerular filtration rate (eGFR, mL/min/1.73 m2) into four subgroups (≥ 90, 60 to < 90, 45 to < 60, and < 45) and two subgroups (≥ 60 and < 60). Adverse drug reaction (ADR) incidence, and changes from baseline in glycosylated hemoglobin (HbA1c), bodyweight, and eGFR were assessed. The percentage of patients experiencing ADRs and serious ADRs was similar across most eGFR subgroups. Polyuria/pollakiuria was the most common ADR. Renal disorders and volume depletion ADRs were more frequent in the subgroups with more severe renal impairment at baseline than in those with an eGFR of 60 to < 90 or ≥ 90 mL/min/1.73 m2. Bodyweight and HbA1c decreased in all subgroups, the latter by - 0.91% to - 0.40% (P < 0.05 vs. baseline). eGFR increased in the 45 to < 60 mL/min/1.73 m2 subgroup (+ 1.42 ± 8.77 mL/min/1.73 m2; P = 0.006). It decreased in the ≥ 90 and 60 to < 90 mL/min/1.73 m2 subgroups (- 8.27 ± 13.73 and - 1.22 ± 10.34 mL/min/1.73 m2; P < 0.001), but not to < 60 mL/min/1.73 m2. In conclusion, there were no new or unexpected safety findings in Japanese patients treated with ipragliflozin for T2DM, and long-term sustained improvements in HbA1c and bodyweight were observed regardless of the presence of renal impairment.

[SURGEON QUESTIONNAIRE FOR ESTABLISHING A SURGEON EDUCATION SYSTEM FOR TRANSURETHRAL LASER RESECTION OF THE PROSTATE (HoLEP)].

(Introduction)HoLEP's role in the surgical management of benign prostatic hyperplasia (BPH) is steadily growing. In this study, a questionnaire containing questions about perioperative management was submitted to HoLEP surgeons to help establish standard surgical training procedures. (Methods)We sent a comprehensive 17 questionnaires on HoLEP procedures to 18 surgeons. The questionnaire asked, "Which method are you using, the 1-LOBE or 3-LOBE method?", "What educational methods are being used for surgeons?", "How long is the catheter insertion period after HoLEP?", and "What is the most difficult problem encountered in surgical HoLEP education and what aspect of training is the most emphasized?" (Results)Sixteen (88.9%) surgeons answered these questionnaires. Five surgeons reported using the one lobe method, five surgeons reported using the three lobe method, and four surgeons answered that it depends on the case. Regarding educational methods, the main answer was that it is important to evaluate pre-HoLEP imaging tests such as MRI and cystoscopy and to simulate surgery for education. Regarding the postoperative catheter insertion period, 1 day: 1 surgeon, 2 days: 9 surgeons, 3 days: 3 surgeons, 4 days or more: 1 surgeon. The most important thing reported for surgical education was to help beginners understand the characteristics of lasers, including direction, distance to prostate tissue, and adenoma removal. (Conclusions)The surgeons' responses clearly indicated some differences in practices between institutions. More detailed data from these results will provide a step towards designing standardized surgical and educational protocols for HoLEP.

Real-World Evidence for Long-Term Safety and Effectiveness of Ipragliflozin in Japanese Patients with Type 2 Diabetes Mellitus: final Results of a 3-Year Post-Marketing Surveillance Study (STELLA-LONG TERM).

OBJECTIVE: To evaluate the long-term safety and effectiveness of ipragliflozin in real-world clinical practice in Japanese patients with type 2 diabetes mellitus (T2DM). RESEARCH DESIGN AND METHODS: This post-marketing surveillance study (STELLA-LONG TERM) included Japanese patients newly initiated on ipragliflozin between 17 July 2014 and 16 October 2015 (data lock: 30 September 2019). Survey items included demographics, treatments, adverse drug reactions (ADRs), vital signs, and laboratory variables. RESULTS: Of 11,424 registered patients, safety and efficacy analysis sets comprised of 11,051 and 8,763 patients, respectively. ADRs occurred in 2,129 patients (19.27%) and serious ADRs occurred in 210 patients (1.90%). Renal and urinary disorders (n = 739, 6.69%), particularly polyuria/pollakiuria (n = 612, 5.54%) and volume depletion-events, including dehydration (n = 243, 2.20%), comprised the most common ADRs. Mean (SD) change in hemoglobin A1c (─0.66 [1.25] %), fasting plasma glucose (─28.8 [50.1] mg/dL) and body weight (─3.33 [4.32] kg) from baseline to 36 months were statistically significant (P < 0.001). CONCLUSIONS: The safety profile of long-term ipragliflozin treatment in routine clinical practice is consistent with previously reported interim data at 12 or 24 months and pre-approval clinical trials. Ipragliflozin treatment was also associated with sustained improvements in efficacy parameters for over 3 years.

Kif1c regulates osteoclastic bone resorption as a downstream molecule of p130Cas.

Podosome formation in osteoclasts is an important initial step in osteoclastic bone resorption. Mice lacking c-Src (c-Src-/- ) exhibited osteopetrosis due to a lack of podosome formation in osteoclasts. We previously identified p130Cas (Crk-associated substrate [Cas]) as one of c-Src downstream molecule and osteoclast-specific p130Cas-deficient (p130CasΔOCL-/- ) mice also exhibited a similar phenotype to c-Src-/- mice, indicating that the c-Src/p130Cas plays an important role for bone resorption by osteoclasts. In this study, we performed a cDNA microarray and compared the gene profiles of osteoclasts from c-Src-/- or p130CasΔOCL-/- mice with wild-type (WT) osteoclasts to identify downstream molecules of c-Src/p130Cas involved in bone resorption. Among several genes that were commonly downregulated in both c-Src-/- and p130CasΔOCL-/- osteoclasts, we identified kinesin family protein 1c (Kif1c), which regulates the cytoskeletal organization. Reduced Kif1c expression was observed in both c-Src-/- and p130CasΔOCL-/- osteoclasts compared with WT osteoclasts. Kif1c exhibited a broad tissue distribution, including osteoclasts. Knockdown of Kif1c expression using shRNAs in WT osteoclasts suppressed actin ring formation. Kif1c overexpression restored bone resorption subsequent to actin ring formation in p130CasΔOCL-/- osteoclasts but not c-Src-/- osteoclasts, suggesting that Kif1c regulates osteoclastic bone resorption in the downstream of p130Cas (191 words). SIGNIFICANCE OF THE STUDY: We previously showed that the c-Src/p130Cas (Cas) plays an important role for bone resorption by osteoclasts. In this study, we identified kinesin family protein 1c (Kif1c), which regulates the cytoskeletal organization, as a downstream molecule of c-Src/p130Cas axis, using cDNA microarray. Knockdown of Kif1c expression using shRNAs in wild-type osteoclasts suppressed actin ring formation. Kif1c overexpression restored bone resorption subsequent to actin ring formation in osteoclast-specific p130Cas-deficient (p130CasΔOCL-/- ) osteoclasts but not c-Src-/- osteoclasts, suggesting that Kif1c regulates osteoclastic bone resorption in the downstream of p130Cas.