Tumor Growth Measurement

Our laboratory uses a mouse model to study preventative and therapeutic vaccination strategies for human papilloma virus (HPV)-associated tumors. For preventative vaccination studies, six- to eight-week-old female C57BL/6 mice are injected subcutaneously with LPDI on days 0 and 5 and are challenged on day 10 with a subcutaneous injection of 10 E7-expressing TC-1 tumor cells with tumor growth measured three times weekly. 

Treatment started when the tumors were measurable and tumor growth was assessed by calipers every 3 days. Mice were sacrificed when tumors reached a volume that hampered them. 

Dose (in vinca equivalents), administered on days 2, 5, 8, required to produce a 50% suppression of tumor growth relative to controls. The tumors were measured 28 days after tumor inoculation (s.c., I x 10 cells). T222 Animals pretreated with 350 R -/-radiation 24 hr prior to tumor inoculation and dosed on days 3, 6, and 9. 

Indeed, TCA (42) at a concentration of 10 Xg/mL, has been shown to elevate levels of ROS, as measured by flow cytometry. Consistent with earlier observations regarding structure-activity relationships, Me-TCA (44) showed 3-fold induction of ROS while dihydro-TCA (43) had no effect on the cellular levels of ROS.It is noteworthy that parthenolide (45), a sesquiterpene natural product structurally related to TCA, has previously been shown to increase the levels of ROS by glutathione depletion in hepatocellular carcinoma cell lines. In a separate study, parthenolide was able to inhibit DNA synthesis, cause cell cycle arrest, and induce apoptosis which are important mechanisms for controlling tumor growth. 

Rotating culture vessels such as simulated microgravity systems are primarily used to study 3-D tumor growth and differentiation. However, mixed cell populations combined with matrix proteins can be used to generate a complex microenvironment in which cell-cell interactions and invasion can be measured (95). A similar system has also been described for the coculture of endothelial cells, myofibroblasts, and tumor cell clusters embedded in Matrigel . Differential labeling of the cell populations enables their invasion and the effects of inhibitors to be measured (96). 

Each group should be made by at least 5-6 animals to follow tumor growth and 2-3 for each scheduled time point for the measurement of the residual expression of the target gene. 

The effect of many drugs used to treat cancer also reflects a cumulative action—eg, the extent of binding of a drug to DNA is proportional to drug concentration and is usually irreversible. The effect on tumor growth is therefore a consequence of cumulative exposure to the drug. Measures of cumulative exposure, such as AUC, provide a means to individualize treatment. 

Tumor growth rate, as assessed by repeated measure of tumor burden, is analyzed using a repeated measures test (32). 

Formation of regional lymph node metastasis can be an important step in dissemination of cancer cells. In colorectal cancer, lymph node metastasis frequently occurs in patients (7, 8) and is an important factor in staging the disease. In particular, the metastatic lymph node ratio (LNR number of metastatic lymph nodes/number of examined lymph nodes) is predictive of overall survival (OS) and disease-free survival (DFS) in colorectal cancer patients (9, 10). Hence, an animal model of colorectal cancer with measurable lymphatic metastasis that allows for rapid evaluation of the effects of candidate treatment regimens on primary tumor growth and lymph node metastasis would be of great value. 

Fig. 14.3. Treatment effect on tumor growth. (A) Treatment with IFL significantly (P= 0.0009, RM ANOVA) inhibited the growth of FIT-29LP tumors as measured by bioluminescence imaging. (B) Tumor weight measurements confirmed antitumor effects of IFL. Mean tumor weight in the IFL group was significantly (P< 0.0001, one-way ANOVA) lower...

Perform statistical analysis utilizing repeated measures ANOVA (JMP software, Version 5 from SAS Institute, Cary, NC) to evaluate the treatment effects on tumor growth. Compare tumor weight measurements between treatment groups utilizing one-way ANOVA. 

In parallel to these studies, carbamate compounds 1 and 11-14 were assessed for their antitumor efficacy in mouse cancer xenograft models.15 When implanted human colon cancer CXF280 xenografts were grown within mice for fourteen days, doses of test compounds were administered orally. After a three-week regimen, excised tumor volumes were measured and the percent inhibition of tumor growth was calculated. From this investigation, capecitabine (1) was found to be the most effective treatment, and was furthermore found not to cause intestinal toxicity.16 All of these preclinical observations contributed to the selection of capecitabine as a candidate for further development. 

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