Trial Information

A Pilot Phase II Trial of Celecoxib in Patients With Grade 2 or 3 Endometrioid-type, Clear Cell, and Papillary Serous Uterine Cancers

Endometrial cancer is the most common gynecologic cancer in the United States. The number
of deaths from endometrial cancer has risen 128% since 1987. In 2001, an estimated 38,300
women will develop endometrial cancer (ACS Facts and Figures) and an estimated 6,600 women
will die from endometrial cancer. Preinvasive and well-differentiated endometrial cancers
are hormonally driven and often cured with surgery alone. Higher-grade tumors are usually
not hormonally driven and proliferate via unknown mechanisms. These tumors are largely
responsible for the rising death rate. Responses to toxic treatment protocols for recurrent
endometrial cancer are dismal. Unfortunately, these post-menopausal women also often have
comorbidities, which limit their eligibility for current chemotherapy and radiotherapy
treatments.

Expression of COX-II has been identified in many human cancers including: colon cancer,
gastric cancer, esophogeal cancer, bladder cancer, head and neck cancer, liver cancer,
pancreatic cancer, prostate cancer and breast cancer. COX-II expression is also strongly
expressed in the primary tumor and metastasic site in human cervical cancer. COX-II may
influence cell cycle control by upregulating the proliferative capacity of neoplastic
endometrial cells. Furthermore, COX-II inhibitors inhibit tumor proliferation even in cells
that do not express COX. This suggests an alternative mechanism of action not yet defined
that may play a role in inhibiting the growth of cancer tissue.

The enhanced expression of COX-II has led investigators to use COX-II inhibitors in the
prevention and/or treatment of colon and prostate cancers both in vivo and in vitro.
Celecoxib is now FDA approved for chemoprevention of colon cancer in familial adenomatous
polyposis patients. If it can be shown that COX-II is downregulated by COX-II inhibitors in
endometrial cancer, they may offer similar chemopreventative or chemotherapeutic potentials
that have already been proven in colon cancer.

COX-II enzyme activity may not always correlate with end organ gene expression. Multiple
genes have been implicated in apoptotic pathways and are affected by COX-II inhibitors.
NS-398, a selective COX-II inhibitor causes elevations in APC expression and downregulation
of c-myc. Prostate apoptosis response 4 (Par-4) levels are increased in cells treated with
COX inhibitors. PTEN and hMLH1 are genes which are implicated in malignant transformation
of endometrial tissue. 5-Lipooxygenase (5-LOX) is often correlated with COX-I and COX-II.
Thus, in addition to COX-I and COX-II, these are good candidate genes to study the effects
of COX-II inhibitors on uterine cancers.

Preliminary Data Since COX-II expression is seen in the endometrium and in other
hormonally-dependent tumors, we have investigated the expression of COX-II in endometrial
cancer. Our preliminary studies on 41 fixed samples of benign and neoplastic endometrium
revealed that COX-II was not expressed in benign endometrial tissue, stains minimally (~1%
of tumor cells) in well-differentiated endometrial carcinomas, and stains most strongly in
poorly-differentiated carcinomas (~12% of tumor cells, most staining strongly). COX-II is
expressed in all poorly differentiated uterine cancers. Our study also demonstrated that
COX-II was also strongly expressed in uterine papillary serous carcinomas (UPSC) as well as
clear cell carcinomas of the uterus. These findings were confirmed by Ferrandina, et al. A
small percent of our patients as well as the patients in the Ferrandina study have only 1+
or 1-5% staining. These 'low-expressers' only made up 1/13 (7.7%) of our patients.

COX-II expression in endometrial carcinoma has a slight inverse correlation with apoptosis
(r=-0.534). However, COX-II expression in endometrial carcinoma correlated with
lymphovascular invasion (r=0.69) and depth of invasion (r=0.68). There was no correlation
between COX-II expression and ER (r=0.03) or PR (r=-0.02). The presence of a
poorly-differentiated tumor may imply a hormonally-independent pathway resulting in
de-differentiation. In summary, our preliminary data reveals that COX-II expression is high
in grade 2 and 3 endometrioid-type endometrial cancers, as well as UPSC and clear cell
subtypes and is correlated with known clinical prognostic factors.

Expression of COX-II has been identified in many types of human cancers. Uterine cancer is
the most common gynecologic cancer in the US and there has been an increase in uterine
cancer deaths over the past decade mainly due to the difficulty in treating recurrences in
the more aggressive histologic types. The study co-investigators have also identified
COX-II expression in grade 2 and 3 endometrioid-type, clear cell, and papillary serous types
of uterine cancers. Upregulation of COX-II may control the cell cycle by regulating the
proliferative capacity of neoplastic endometrial cells. This is a Phase II pre-post
intervention comparison study in eligible patients looking at the effects of a COX-II
inhibitor on uterine cancer. The patients whose endometrial biopsy shows grade 2 or 3
endometrioid-type, clear cell, and papillary serous types of uterine cancers will be put on
a selective COX-II inhibitor, Celebrex (Celecoxib) until the day of their surgery. The
expression of COX-II and p21 will be quantified after treatment with Celecoxib in eligible
patients. This expression will be evaluated by performing immunohistochemical staining on
the endometrial biopsy (pre-intervention) and the hysterectomy specimen (post-intervention).
Apoptosis, evaluated by the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-
digoxigenin nick end-labeling (TUNEL) assay, will also be evaluated and compared to COX-II
expression in endometrial cancer in the two specimens, endometrial biopsy
(pre-intervention) and uterus (post-intervention). In addition to IHC analysis and
apoptosis, gene expression of COX-related genes in the post-intervention uterine specimens
will. This gene expression will be compared to matched controls who were not treated with a
COX-II inhibitor. COX-II expression will be correlated with established clinical prognostic
factors including lymphovascular invasion, depth of myometrial invasion and lymph node
involvement. We hypothesize that Celecoxib will downregulate the expression of COX-II in
these tumor types as it does in other similar tumors. We also hypothesize that apoptosis,
as measured with the TUNEL assay, will be increased in areas with less COX-II expression and
should be inversely proportional to cellular p21 expression. Additionally, COX-II
inhibitors affect apoptotic pathways even in cells that do not express COX-II. For low
expressing cells, COX-II inhibitor activity may be better documented with apoptosis. We
hypothesize COX-related gene expression will be altered thus suggesting an up- or
down-regulation of these genes in the end-organ tissue. Documenting downregulation of COX-II
enzyme and altered gene expression in endometrial carcinoma after treatment with Celecoxib
may result in further prospective studies using selective COX-II inhibitors as effective,
well-tolerated chemotherapeutic agents in these uterine cancers that are resistant to many
current therapies.