Synergistic Anti-Tumor Effect of CRM197 & Paclitaxel in Ovarian Cancer

CRM197, an inhibitor of heparin-binding EGF-like growth factor (HB-EGF), produces a synergistic ovarian cancer anti-tumor effect when combined with paclitaxel, according to study results published in the March 15th issue of the International Journal of Cancer.  The investigators, Dr. Shingo Miyamoto and his colleagues, are affiliated with the Fukuoka University in Japan.  “The treatment of CRM197 in conjunction with paclitaxel results in a marked synergistic anti-tumor effect in ovarian cancer cells in vivo, suggesting a novel combination therapy for ovarian cancer patients including those showing chemo-resistance.”  Accordingly, the investigators generally concluded that inhibitory agents against HB-EGF, such as CRM197, represent possible chemotherapeutic and chemosensitizing agents for ovarian cancer. …

CRM197, an inhibitor of heparin-binding EGF-like growth factor (HB-EGF), produces a synergistic ovarian cancer anti-tumor effect when combined with paclitaxel, according to study results published in the March 15th issue of the International Journal of Cancer.  The investigators, Dr. Shingo Miyamoto and his colleagues, are affilitated with the Fukuoka University in Japan.

According to the researchers, HB-EGF plays a pivotal role in tumor growth and clinical outcomes in patients with ovarian cancer, thereby making it a target for future ovarian cancer therapy. CRM197 is a non-toxic variant of the diphtheria toxin.  The investigators conducted studies in which CRM197 and paclitaxel (Taxol®) were tested against ovarian cancer cell cultures (in vitro) and overexpressing HB-EGF ovarian cancer cells which were injected into mice.

The investigators discovered that paclitaxel induced transient ERK activation and sustained activation of JNK and p38 MAPK, effects that were reduced by overexpression of HB-EGF. CRM197 effectively suppressed the paclitaxel-induced anti-apoptotic signals mediated by ERK and Akt and enhanced the pro-apoptotic signals JNK and p38 MAPK.

The investigators also noted that in the mice with ovarian cancer xenografts, paclitaxel and CRM197 completely blocked tumor formation at doses of 10 mg/kg paclitaxel and 5 mg/kg CRM197.

Based on the foregoing, Miyamoto et. al. concluded that “the enhancement of HB-EGF expression abrogates the antitumor effect of paclitaxel by altering the balance of anti-apoptotic and pro-apoptotic signals induced by paclitaxel. The treatment of CRM197 in conjunction with paclitaxel results in a marked synergistic anti-tumor effect in ovarian cancer cells in vivo, suggesting a novel combination therapy for ovarian cancer patients including those showing chemo-resistance.”  Accordingly, the investigators generally concluded that inhibitory agents against HB-EGF, such as CRM197, represent possible chemotherapeutic and chemosensitizing agents for ovarian cancer.

Phase 1 [clinical] study of the use of CRM197 has already started at Fukuoka University for patients with advanced ovarian cancer under the approval of the ethical committee,” the investigators added.

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