Breast cancer stem cells mutations: A new understanding of intratumoral heterogeneity

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Background: Breast cancer has long been recognized as a heterogeneous disease. This has profound implications for diagnosis, treatment and disease recurrence. Oncogenic mutations have been identified in breast cancer cells with stem-like and progenitor properties (BCSC). We have previously reported that BCSC mutations correlated with axillary lymph node metastases. This was even more significant when micrometastatic disease was included. Our hypothesis is that tumor heterogeneity extends to the genetics of BCSC, and that BCSC mutations are better predictors of lymph node status than whole tumor genetics. Methods: BCSC from fresh tissue specimens were matched to their whole tumor specimens. BCSC and whole tumor DNA were sent for PCR-based mutation analysis. Patient data was collected by chart review. Results: Twenty-eight matched BCSC and whole tumor samples were analyzed. PI3K/Akt signaling mutations in PIK3CA, AKT1, HRAS, and MET were identified in BCSC from 10 tumors. In 4 of these, mutations were also identified in the corresponding whole tumor specimens. In 4 patients, mutations were identified in whole tumor samples only. Fourteen tumors had no mutations. Tumor stage, grade, receptor status, and age did not correlate with tumor or BCSC mutation status. In contrast to BCSC mutations, mutation status of the whole tumor did not correlate with micro or macro metastatic disease in the lymph node (p = 0.92). Conclusions: Mutations in BCSC are more predictive of lymph node metastases than mutations identified in the tumors. Thus, PI3K/Akt pathway mutations in tumor precursor cells may have a stronger influence on tumor metastatic potential than mutations identified in whole tumor samples. Whole tumors and BCSC populations demonstrate significant heterogeneity, as mutations identified in BCSC and tumors were not always concordant. Rare BCSC populations must be tested separately as they provide crucial prognostic and treatment information in conjunction with whole tumor genetic analyses.

Overcoming autopsy barriers in pediatric cancer research

BACKGROUND

More than 13,000 children annually in the United States and Canada under the age of 20 will be diagnosed with cancer at a mortality approaching 20% 1,2. Tumor samples obtained by autopsy provide an innovative way to study tumor progression, potentially aiding in the discovery of new treatments and increased survival rates. The purpose of this study was to identify barriers to autopsies and develop guidelines for requesting autopsies for research purposes.

PROCEDURE

Families of children treated for childhood cancer were referred by patient advocacy groups and surveyed about attitudes and experiences with research autopsies. From 60 interviews, barriers to autopsy and tumor banking were identified. An additional 14 interviews were conducted with medical and scientific experts.

RESULTS

Ninety-three percent of parents of deceased children did or would have consented to a research autopsy if presented with the option; however, only half of these families were given the opportunity to donate autopsy tissue for research. The most significant barriers were the physicians' reluctance to ask a grieving family and lack of awareness about research opportunities.

CONCLUSIONS

The value of donating tumor samples to research via an autopsy should be promoted to all groups managing pediatric cancer patients. Not only does autopsy tumor banking offer a potentially important medical and scientific impact, but the opportunity to contribute this Legacy Gift of autopsy tumor tissue also creates a positive outlet for the grieving family. Taking these findings into account, our multidisciplinary team has developed a curriculum addressing key barriers.

The synthetic triterpenoid, CDDO-Me, modulates the proinflammatory response to in vivo lipopolysaccharide challenge

The synthetic triterpenoid, CDDO-Me, has potent antiproliferative and antioxidant properties. However, its immunomodulatory effects in the context of LPS challenge are incompletely defined. Pretreatment with oral CDDO-Me significantly improved survival following lethal-dose LPS challenge in mice. To define this protection further, we measured effects of CDDO-Me pretreatment on splenocyte populations and cytokine production following LPS challenge, using low-level LPS pretreatment as an in vivo control for reducing cytokine production. Despite similar decreases in levels of LPS-inducible, circulating proinflammatory cytokines (IL-12p70, IFN-gamma, IL-6, IL-17, and IL-23) and increases in heme oxygenase 1 (HO-1) protein expression, low-dose LPS and CDDO-Me pretreatments markedly differed in their overall response profiles. Splenocytes from LPS-pretreated mice contained reduced numbers of dendritic cells, increased percentages of Th17 and T-regulatory cells, lower levels of TLR-inducible IL-6, and higher levels of TLR-inducible IL-10. In contrast, CDDO-Me protection against LPS challenge had no impact on absolute numbers or distribution of splenocyte subsets, despite attenuating in vivo induction of proinflammatory cytokines in an IL-10-independent manner. Together, these results suggest that CDDO-Me pretreatment uniquely confers protection against LPS challenge by modulating the in vivo immune response to LPS. Thus, CDDO-Me potentially represents a novel oral agent for use in LPS-mediated inflammatory diseases.

Human neuroblastoma cells rapidly enter cell cycle arrest and apoptosis following exposure to C-28 derivatives of the synthetic triterpenoid CDDO

Synthetic triterpenoids, such as 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) and its derivatives, are an extremely potent class of new anti-cancer therapeutic agents, characterized by high anti-tumor potency and low toxicity to normal tissues. This report is the first to investigate the effects of C-28 derivatives of CDDO on 22 pediatric solid tumor cell lines, including neuroblastoma, rhabdomyosarcoma, osteosarcoma, and Ewing's sarcoma. We determined IC(50)s in the range of 5-170 nM for inhibition of colony formation and DNA synthesis, and 110-630 nM for metabolic cell death and decrease in cell number, using the C-28 CDDO analogs, CDDO methyl ester (CDDO-Me), CDDO imidazolide (CDDO-Im), CDDO ethyl amide (CDDO-EA), CDDO trifluoroethyl amide (CDDO-TFEA), and CDDO diethylamide (CDDO-DE). After treatment of human neuroblastoma cells with CDDO-Me, cell cycle studies show depletion of the S-phase, while apoptosis studies show conformational activation and mitochondrial translocation of Bax protein, as well as activation of caspases -3 and -8. These data demonstrate the potential utility of CDDO analogs as promising novel therapeutic agents for high-risk pediatric solid tumors.