Intravesical administration of pirarubicin against superficial bladder cancer: Relationship between tumor tissue concentration and exposure time in the bladder or therapeutic effect

Safety Assessment of Ultrasound-Assisted Intravesical Chemotherapy in Normal Dogs: A Pilot Study

Intravesical chemotherapy after transurethral resection is a treatment option in patients with non-muscle invasive bladder cancer. The efficacy of intravesical chemotherapy is determined by the cellular uptake of intravesical drugs. Therefore, drug delivery technologies in the urinary bladder are promising tools for enhancing the efficacy of intravesical chemotherapy. Ultrasound-triggered microbubble cavitation may enhance the permeability of the urothelium, and thus may have potential as a drug delivery technology in the urinary bladder. Meanwhile, the enhanced permeability may increase systemic absorption of intravesical drugs, which may increase the adverse effects of the drug. The aim of this preliminary safety study was to assess the systemic absorption of an intravesical drug that was delivered by ultrasound-triggered microbubble cavitation in the urinary bladder of normal dogs. Pirarubicin, a derivative of doxorubicin, and an ultrasound contrast agent (Sonazoid) microbubbles were administered in the urinary bladder. Ultrasound (transmitting frequency 5 MHz; pulse duration 0.44 μsec; pulse repetition frequency 7.7 kHz; peak negative pressure −1.2 MPa) was exposed to the bladder using a diagnostic ultrasound probe (PLT-704SBT). The combination of ultrasound and microbubbles did not increase the plasma concentration of intravesical pirarubicin. In addition, hematoxylin and eosin staining showed that the combination of ultrasound and microbubble did not cause observable damages to the urothelium. Tissue pirarubicin concentration in the sonicated region was higher than that of the non-sonicated region in two of three dogs. The results of this pilot study demonstrate the safety of the combination of intravesical pirarubicin and ultrasound-triggered microbubble cavitation, that is, ultrasound-assisted intravesical chemotherapy.

Efficacy of Bladder Intravesical Chemotherapy with Three Drugs for Preventing Non-Muscle-Invasive Bladder Cancer Recurrence

Epirubicin, gemcitabine, and pirarubicin are widely used as first-line drugs for intravesical chemotherapy to prevent tumor recurrence after transurethral bladder tumor resection for non-muscle-invasive bladder cancer (NMIBC). However, which drug is better is less discussed. A total of 335 NMIBC patients administered intravesical chemotherapy underwent transurethral bladder tumor resection (TURBT) in our hospital from October 2015 to October 2019. After TURBT, all the patients received standard intravesical chemotherapy. Through clinical data collection and telephone follow-up, the tumor recurrence and adverse reactions of all patients after bladder perfusion treatment were counted. Recurrence was defined as new tumor appearance in the bladder. Of the 335 patients who underwent intravesical chemotherapy, 109 patients received epirubicin and 114 patients and 112 patients were given gemcitabine and pirarubicin, respectively. According to the general information of the patients, the patients were divided into intermediate-risk and high-risk bladder cancer and compared separately. There was no statistical difference in clinical and pathological features between different groups (P > 0.05). The recurrence rate of intermediate-risk bladder cancer patients shows no difference between three groups (P > 0.05). As for the high-risk bladder cancer patients, it is found that the 1-year recurrence rate between three groups was not statistically significant (P > 0.05), whereas the 2-year recurrence rate of patients given gemcitabine (9.87%) was significantly lower than that of epirubicin (25.37%) and pirarubicin (24.32%), and the difference was statistically significant (P < 0.017, Bonferroni adjusted P value). The Kaplan-Meier survival curves showed that the recurrence-free survival rate of patients received gemcitabine was significantly higher than that of the other two groups. Comparing the incidence of adverse reactions during the infusion of the three groups of patients, the differences were not statistically significant (P > 0.05). In patients with high-risk non-muscle-invasive bladder cancer, the application of gemcitabine intravesical chemotherapy is related with a relatively lower recurrence rate but similar incidence of adverse reactions.

Preparation, characterization and evaluation of [125I]-pirarubicin: A new therapeutic agent for urinary bladder cancer with potential for use as theranostic agent

Improving urinary bladder cancer diagnosis, follow-up, and therapy tools to overcome existing limitations and increase survival rates is a highly desirable goal. In the current investigation, pirarubicin, a new generation antineoplastic anthracycline, was labeled with [¹²⁵I] via an electrophilic substitution reaction. The reaction parameters were studied to optimize the iodination process. The labeled compound showed high radiochemical yield (98.5 ± 2.1%) and consistently remained above 90% for more than 20 h at room temperature and in the presence of serum at 37 °C. The binding of [¹²⁵I]-pirarubicin to its target DNA-human topoisomerase II complex was assessed in-silico. The in-vitro tracer uptake by cancer cells was high and reached saturation (88.4 ± 2.3%) after 3 h with nuclei to cells ratio of 40 ± 1.2%. The labeled compound antiproliferative effect was much stronger than the unlabelled pirarubicin, as cleared by the growth inhibition test. Radiotoxicity improved cancer cells drug cytotoxicity. The in-vivo evaluation results showed that the [¹²⁵I]-pirarubicin tends to preferentially accumulate in urinary bladder cancerous tissues.

MKP-1 overexpression is associated with chemoresistance in bladder cancer via the MAPK pathway

Mitogen activated protein kinase phosphatase-1 (MKP-1) has been revealed to be overexpressed in bladder cancer, particularly in non-muscle invasive bladder cancer. MKP-1 may also be associated with chemotherapy resistance. However, the underlying mechanism is yet to be elucidated. The current study investigated the expression of MKP-1 by performing immunohistochemistry in surgically resected specimens obtained from primary and recurrent patients with bladder cancer. The results revealed that MKP-1 expression increased in recurrent patients. Additionally, a 3D model of the human bladder cancer cell line, RT112, was established to determine the role of MKP-1 in drug resistance. The results demonstrated that MKP-1 overexpression protected bladder cancer cells against cell death. Contrarily, MKP-1 knockdown was revealed to sensitize cells to death. In addition, the application of MAPK inhibitors effectively increased RT112 cell sensitivity to pirarubicin. In conclusion, the results of the current study indicated that MKP-1 treatment resulted in bladder cancer cell chemoresistance via JNK, ERK and p38 pathways. MKP-1 may also serve as a potential therapeutic target for chemoresistance in patients with bladder cancer.

Capsaicinoids enhance chemosensitivity to chemotherapeutic drugs

Cytotoxic chemotherapy is the mainstay of cancer treatment. Conventional chemotherapeutic agents do not distinguish between normal and neoplastic cells. This leads to severe toxic side effects, which may necessitate the discontinuation of treatment in some patients. Recent research has identified key molecular events in the initiation and progression of cancer, promoting the design of targeted therapies to selectively kill tumor cells while sparing normal cells. Although, the side effects of such drugs are typically milder than conventional chemotherapies, some off-target effects still occur. Another serious challenge with all chemotherapies is the acquisition of chemoresistance upon prolonged exposure to the drug. Therefore, identifying supplementary agents that sensitize tumor cells to chemotherapy-induced apoptosis and help minimize drug resistance would be valuable for improving patient tolerance and response to chemotherapy. The use of effective supplementary agents provides a twofold advantage in combination with standard chemotherapy. First, by augmenting the activity of the chemotherapeutic drug it can lower the dose needed to kill tumor cells and decrease the incidence and severity of treatment-limiting side effects. Second, adjuvant therapies that lower the effective dose of chemotherapy may delay/prevent the development of chemoresistance in tumors. Capsaicinoids, a major class of phytochemical compounds isolated from chili peppers, have been shown to improve the efficacy of several anti-cancer drugs in cell culture and animal models. The present chapter summarizes the current knowledge about the chemosensitizing activity of capsaicinoids with conventional and targeted chemotherapeutic drugs, highlighting the potential use of capsaicinoids in novel combination therapies to improve the therapeutic indices of conventional and targeted chemotherapeutic drugs in human cancers.

Anaphylactic shock due to intravesical administration of pirarubicin hydrochloride for the fifth time

We report the first case of anaphylaxis induced by intravesical administration of pirarubicin hydrochloride during spinal anesthesia. The patient was a 64-year-old woman being followed up for transitional cell carcinoma of the bladder. Anaphylaxis occurred the fifth time pirarubicin hydrochloride was administered intravesically. Pirarubicin hydrochloride, an anthracycline antitumor antibiotic that is widely used for intravesical instillation chemotherapy, is administered at the end of surgery. Because this is about the time that the patient is leaving the operating room, attention to patient monitoring tends to be divided. Because anaphylaxis may occur at this time, staff should remain vigilant of the risk of anaphylaxis.

Capsaicin enhances anti-proliferation efficacy of pirarubicin via activating TRPV1 and inhibiting PCNA nuclear translocation in 5637 cells

The recurrence of bladder cancer after surgery with or without chemotherapy remains a major challenge in bladder cancer treatment. Previous studies have shown that transient receptor potential vanilloid 1 (TRPV1) acts as a tumor suppressor through inducing apoptosis in bladder cancer cells. However, whether activation of TRPV1 has any synergistic effects with pirarubicin (THP), one of main drugs used in urinary bladder instillation chemotherapy to improve chemotherapeutic efficacy has remained elusive. The present study verified that TRPV1 was differentially expressed in bladder cancer cell lines. Furthermore, activation of TRPV1 by capsaicin was shown to induce growth inhibition of 5637 cells in which TRPV1 was highly expressed, while the growth of T24 cells, which express TRPV1 at low levels, was not affected. In addition, the present study demonstrated that activation of TRPV1 enhanced the anti‑proliferative effects of pirarubicin using an MTT assay and cell cycle analysis. Finally, immunofluorescent microscopy revealed that activation of TRPV1 prevented the translocation of proliferating cell nuclear antigen to the nucleus. This phenomenon was reversed by pre‑treatment with capsazepine, a specific TRPV1 antagonist. In conclusion, the present study confirmed the anti‑tumor activity of TRPV1 against bladder cancer. Activation of TRPV1 may be applied as a novel strategy to treat bladder cancer or enhance the therapeutic efficacy of traditional chemotherapeutic drugs.