Cetuximab therapy in the treatment of metastatic colorectal cancer: the future frontier? Int J Surg. 2013;11:507-513. [PMID: 23660586 DOI: 10.1016/j.ijsu.2013.04.014]

KRAS-specific antibody binds to KRAS protein inside colorectal adenocarcinoma cells and inhibits its localization to the plasma membrane

Colorectal cancer (CRC) is the third highest incidence cancer and a leading cause of cancer mortality worldwide. To date, chemotherapeutic treatment of advanced CRC that has metastasized has a dismayed success rate of less than 30%. Further, most (80%) sporadic CRCs are microsatellite-stable and are refractory to immune checkpoint blockade therapy. KRAS is a gatekeeper gene in colorectal tumorigenesis. Nevertheless, KRAS is ‘undruggable’ due to its structure. Thus, focus has been diverted to develop small molecule inhibitors for its downstream effector such as ERK/MAPK. Despite intense research efforts for the past few decades, no small molecule inhibitor has been in clinical use for CRC. Antibody targeting KRAS itself is an attractive alternative. We developed a transient ex vivo patient-derived matched mucosa-tumor primary culture to assess whether anti-KRAS antibody can be internalized to bind and inactivate KRAS. We showed that anti-KRAS antibody can enter live mucosa-tumor cells and specifically aggregate KRAS in the cytoplasm, thus hindering its translocation to the inner plasma membrane. The mis-localization of KRAS reduces KRAS dwelling time at the site where it tethers to activate downstream effectors. We previously showed that expression of SOX9 was KRAS-mutation-dependent and possibly a better effector than ERK in CRC. Herein, we showed that anti-KRAS antibody treated tumor cells have less intense SOX9 cytoplasmic and nuclear staining compared to untreated cells. Our results demonstrated that internalized anti-KRAS antibody inhibits KRAS function in tumor. With an efficient intracellular antibody delivery system, this can be further developed as combinatorial therapeutics for CRC and other KRAS-driven cancers.

An internalizing antibody targeting of cell surface GRP94 effectively suppresses tumor angiogenesis of colorectal cancer

Colorectal cancer (CRC) is one of the life-threatening malignancies worldwide. Thus, novel potential therapeutic targets and therapeutics for the treatment of CRC need to be identified to improve the clinical outcomes of patients with CRC. In this study, we found that glucose-regulated protein 94 (GRP94) is overexpressed in CRC tissues, and its high expression is correlated with increased microvessel density. Next, through phage display technology and consecutive in vitro functional isolations, we generated a novel human monoclonal antibody that specifically targets cell surface GRP94 and shows superior internalizing activity comparable to trastuzumab. We found that this antibody specifically inhibits endothelial cell tube formation and simultaneously promotes the downregulation of GRP94 expression on the endothelial cell surface. Finally, we demonstrated that this antibody effectively suppresses tumor growth and angiogenesis of HCT116 human CRC cells without causing severe toxicity in vivo. Collectively, these findings suggest that cell surface GRP94 is a novel potential anti-angiogenic target in CRC and that antibody targeting of GRP94 on the endothelial cell surface is an effective strategy to suppress CRC tumor angiogenesis.

[Predictive factors for mandibular osteoradionecrosis after irradiation of head and neck cancers]

The identification of the different risk factors for mandibular osteoradionecrosis (ORN) must be done before and after the management of patients with head and neck cancer. Various clinical criteria for this severe radiation-induced complication are related to the patient (intrinsic radiosensitivity, malnutrition associated with thin weight loss, active smoking intoxication, microcapillary involvement, precarious oral status, hyposalivation) and/or related to the disease (oral cavity, large tumor size, tumor mandibular invasion). Therapeutic risk factors are also associated with a higher risk of ORN (primary tumor surgery, concomitant radio-chemotherapy, post-irradiation dental avulsion, preventive non-observance with the absence of stomatological follow-up and daily installation of gutters fluoride and, non-observance curative healing treatments). Finally, various dosimetric studies have specified the parameters in order to target the dose values distributed in the mandible, which increases the risk of ORN. An mean mandibular dose greater than 48-54Gy and high percentages of mandibular volume receiving 40 to 60Gy appear to be discriminating in the risk of developing an ORN.

Monoclonal antibodies and chimeric antigen receptor (CAR) T cells in the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer deaths worldwide. Besides common therapeutic approaches, such as surgery, chemotherapy, and radiotherapy, novel therapeutic approaches, including immunotherapy, have been an advent in CRC treatment. The immunotherapy approaches try to elicit patients` immune responses against tumor cells to eradicate the tumor. Monoclonal antibodies (mAbs) and chimeric antigen receptor (CAR) T cells are two branches of cancer immunotherapy. MAbs demonstrate the great ability to completely recognize cancer cell-surface receptors and blockade proliferative or inhibitory pathways. On the other hand, T cell activation by genetically engineered CAR receptor via the TCR/CD3 and costimulatory domains can induce potent immune responses against specific tumor-associated antigens (TAAs). Both of these approaches have beneficial anti-tumor effects on CRC. Herein, we review the different mAbs against various pathways and their applications in clinical trials, the different types of CAR-T cells, various specific CAR-T cells against TAAs, and their clinical use in CRC treatment.

Outcome of indeterminate liver lesions on computed tomography in patients with colorectal cancer

Introduction The aim of this study was to determinate the outcome of indeterminate liver lesions on computed tomography (CT) in patients with a background history of colorectal cancer (CRC) and to identify clinicopathological variables associated with malignancy in these lesions. A secondary aim was to devise a management algorithm for such patients. Methods Patients referred to our institution with indeterminate liver lesions on CT with a background history of CRC between January 2012 and December 2014 were included in the study. Clinicopathological factors, surveillance period and histological findings were analysed. Results Fifty-six patients with indeterminate liver lesions were identified. Fifty-three (94.6%) of these required further imaging (magnetic resonance imaging [MRI; n=50] and positron emission tomography combined with CT [n=3]). For the patients who had MRI, the underlying diagnosis was benign in 19 and colorectal liver metastasis (CRLM) in 8 while 23 patients and an indeterminate lesion. In cases that remained indeterminate following MRI, liver resection was performed in 2 patients for a high suspicion of CRLM while the 21 remaining patients underwent interval surveillance (median: 9 months, range: 3-52 months). Of these 21 patients, 14 had benign lesions while CRLM was noted in 6 patients and an incidental hepatocellular carcinoma in a single patient. Age ≥65 years was the only statistically significant clinicopathological factor in predicting an underlying malignancy in patients with indeterminate liver lesions on CT. Conclusions Over a third of the patients diagnosed with indeterminate liver lesions on CT subsequently showed evidence of CRLM. These indeterminate lesions are more likely to be malignant in patients aged ≥65 years.

Resection margin influences the outcome of patients with bilobar colorectal liver metastases

AIM

To evaluate the outcome of patients with bilobar colorectal liver metastases (CRLM) and identify clinico-pathological variables that influenced survival.

METHODS

Patients with bilobar CRLM were identified from a prospectively maintained hepatobiliary database during the study period (January 2010-June 2014). Collated data included demographics, primary tumour treatment, surgical data, histopathology analysis and clinical outcome. Down-staging therapy included Oxaliplatin- or Irinotecan- based regimens, and Cetuximab was also used in patients that were K-RAS wild-type. Response to neo-adjuvant therapy was assessed at the multi-disciplinary team meeting and considered for surgery if all macroscopic CRLM were resectable with a clear margin while preserving sufficient liver parenchyma.

RESULTS

Of the 136 patients included, thirty-two (23.5%) patients were considered inoperable and referred for palliative chemotherapy, and thirty-four (25%) patients underwent liver resection. Seventy (51.4%) patients underwent down-staging therapy, of which 37 (52.8%) patients responded sufficiently to undergo liver resection. Patients that failed to respond to down-staging therapy (n = 33, 47.1%) were referred for palliative therapy. There was a significant difference in overall survival between the three groups (surgery vs down-staging therapy vs inoperable disease, P < 0.001). All patients that underwent hepatic resection, including patients that had down-staging therapy, had a significantly better overall survival compared to patients that were inoperable (P < 0.001). On univariate analysis, only resection margin significantly influenced disease-free survival (P = 0.017). On multi-variate analysis, R0 resection (P = 0.030) and female (P = 0.036) gender significantly influenced overall survival.

CONCLUSION

Patients undergoing liver resection with bilobar CRLM have a significantly better survival outcome. R0 resection is associated with improved disease-free and overall survival in this patient group.

Systematic review and meta-analysis of the risk of severe and life-threatening thromboembolism in cancer patients receiving anti-EGFR monoclonal antibodies (cetuximab or panitumumab)

Cancer-associated thromboembolism is a substantial problem in clinical practice. An increase in the level of fibrinopeptide A (a substance associated with hypercoagulable states) has been observed in humans exposed to fluorouracil. Anti-EGFR monoclonal antibodies cetuximab and panitumumab, which are now widely used in patients with metastatic colorectal cancer, could prolong the uncovering of endothelial structures resulting from flouorouracil or other co-administered agents, thus favouring several factors leading to thromboembolism. We performed a systematic review and meta-analysis of randomised, controlled trials assessing whether cancer patients receiving anti-EGFR monoclonal antibodies cetuximab and panitumumab are at increased risk of thromboembolic events. We searched electronic databases (Medline, Embase, Web of Science, Central) and reference lists. Phase II/III randomised, controlled trials comparing standard anti-cancer regimens with or without anti-EGFR monoclonal antibodies and reporting serious venous thromboembolic events were included in the analysis. Seventeen studies (12,870 patients) were considered for quantitative analysis. The relative risk (RR) for venous thromboembolism (18 comparisons) was 1.46 (95% CI 1.26 to 1.69); the RR of pulmonary embolism, on the basis of eight studies providing nine comparisons, was 1.55 (1.20 to 2.00). Cancer patients receiving anti-EGFR monoclonal antibodies-containing regimens are approximately 1.5 times more likely to experience venous or pulmonary embolism, compared to those treated with the same regimens without anti-EGFR monoclonal antibodies. Clinicians should consider patient's baseline thromboembolic risk when selecting regimens that include cetuximab or panitumumab. Potential non-reporting of these important adverse events remains a concern. PROSPERO registration number is CRD42014009165.

Does nodal status influence survival? Results of a 19-year systematic lymphadenectomy experience during lung metastasectomy of colorectal cancer

OBJECTIVES

Resection of pulmonary metastases originating from colorectal cancer is increasingly considered. While several adverse risk factors for long-term outcome are known, the selection of patients who may benefit from surgery remains unclear. In particular, few studies have addressed the impact of lymph node involvement, and signification of the hilar or mediastinal level of extent.

METHODS

We retrospectively reviewed the data of 320 patients operated in two thoracic departments between 1992 and 2011. Appropriate statistical tests were used to compare groups at risk.

RESULTS

There were 105 women and 215 men with a mean age of 63.3 years (range: 27-86) at the time of metastasectomy. Lymph node involvement appeared as a significant prognostic factor in both the univariate and multivariate analyses [median survival: 94 months N0 vs 42 months N+, P < 0.0001; OR = 0.573 (0.329-1), P = 0.05]. Survival was similar for hilar and mediastinal locations (median survival: 47 months vs 37 months, respectively, P = 0.14). Associated hepatic metastases had a negative impact on survival in both univariate and multivariate analyses [median survival: 74 months vs 47 months, P < 0.01; OR = 0.387 (0.218-0.686), P = 0.001]. Multiple lung metastases significantly decreased survival in univariate analysis only (median survival: 81 months vs 55 months, P < 0.01). Disease-free survival and preoperative carcinoembryonic antigen had no impact on survival.

CONCLUSIONS

While lymph node involvement was associated with decreased survival, the impact of mediastinal location on survival did not differ from that of hilar location. Consequently, these patients should not be excluded from surgical treatment.

A miR-30d antisense oligonucleotide inhibits proliferation and promotes apoptosis of colon cancer cells

AIM: To investigate the expression of miR-30d in colon cancer tissues and the effect of a miR-30d antisense oligonucleotide (ASO) on the proliferation and apoptosis of colon cancer cells.

METHODS: The expression of miR-30d in 102 colon cancer tissues and matched tumor-adjacent tissues was detected by real-time quantitative PCR. After colon cancer cells were transfected with a miR-30d ASO, cell proliferation and apoptosis were measured by MTT assay, colony formation assay and flow cytometry.

RESULTS: miR-30d was overexpressed in 52.94% (54/102) of colon cancer tissues, and the positive rate of miR-30d overexpression was significantly higher in colon cancer tissues than in tumor-adjacent colon tissues (P < 0.05). Transfection of miR-30d ASO significantly reduced the expression of miR-30d (P < 0.05), decreased cell survival at 24, 48 and 96 h (all P < 0.05), inhibited colony formation (P < 0.05), and increased apoptosis (P < 0.05) compared with control cells. In addition, the expression of Bcl-2 mRNA and protein was significantly decreased after the expression of miR-30d was down-regulated.

CONCLUSION: MiR-30d is overexpressed in human colon cancer. Inhibition of the expression of miR-30d can effectively inhibit growth and promotes apoptosis of colon cancer cells. MiR-30d may become a new target for the regulation of gene expression in colon cancer.