Nasopharynx carcinoma

Velutin (flavone) Terpene Lethedon tannaensis (Thymelaeaceae) TOPI (calf thymus) [cytotoxic -human nasopharynx carcinoma KB cells (5)] 9.3Ft... 

Four compounds isolated from C. hindsii [37], maytenfolone-A (10), celasdin A (11), celasdin B (12) and celasdin C (13) were tested for cytotoxicity in four cancer cell lines. The lines used were KB (nasopharynx carcinoma), HEPA-2B (hepatoma), HELA (cervix carcinoma) and COLO-205 (colon carcinoma). Compound (10) showed... 

Bruceanols G (70) and H (71) were evaluated against three cancer cell lines SK-MEL-5 (melanoma), COLO-205 (colon cancer), and KB (nasopharynx carcinoma). These compounds were only marginally cytotoxic in the melanoma cell line with ED50 values of 4.08 and 6.37 pM, respectively. However, bruceanol G (70) showed activity against the COLO-205 and KB cell lines with ED50 values of 0.44 and 0.55 pM, respectively [38],... 

Further investigation of the B. antidysenterica extract [10] led to the isolation of three new quassinoids bmceanol-D (17), -E (18), -F (19), and known a diSsmoiAs yadanzioside-N A), bruceantin (1), and isobnicein-B (5). Bruceanol-D (17) and -F (19) were both obtained as colorless amorphous solids and bruceanol-E (18) was obtained as colorless needles. They showed cytotoxicity for tumor cells such as KB (nasopharynx carcinoma), A-549 (human lung carcinoma), HCT-8 (human colon tumor), P-388 (murine lymphocytic lei emia), TE-671 (human medulloblastoma), and RPMI-7951 (human melanoma), as shown in Table 1. 

Fractions of a water-alcohol extract of spreading dogbane exhibited cytotoxic activity in human nasopharynx carcinoma cells (Kupchan et al. 1964). 

Earlier, some of the same considerations had led me in 1957 to initiate a study of amphibian venoms of the steroidal bufadienolide (6) type as potential sources of new antineoplastic substances. Eventually we found that some of the toad venom bufadienolides such as marinobufagin significantly inhibit growth of the National Cancer Institute s KB cell line derived from a human nasopharynx carcinoma and lead to a curative response with the murine Ehrlich ascites system (7). However, the therapeutic indices were unattractive for further development. So the effort was extended in 1965-66, as Just noted, to encompass a geographically far-reaching area (Asia, Africa, Australia etc.) and an extensive research program to evaluate marine invertebrates and arthropods for structurally unique and useful anticancer constituents. Subsequently we isolated the first such invertebrate antineoplastic constituents (8-12). Meanwhile, our early expectations have been abundantly realized and the discovery of the bryostatins provides a splendid illustration. 

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