Recent updates in the clinical use of platinum compounds for the treatment of gastrointestinal cancers

In Vitro Cytotoxicity Evaluation of Plastoquinone Analogues against Colorectal and Breast Cancers along with In Silico Insights

Colorectal cancer (CRC) and breast cancer are leading causes of death globally, due to significant challenges in detection and management. The late-stage diagnosis and treatment failures require the discovery of potential anticancer agents to achieve a satisfactory therapeutic effect. We have previously reported a series of plastoquinone analogues to understand their cytotoxic profile. Among these derivatives, three of them (AQ-11, AQ-12, and AQ-15) were selected by the National Cancer Institute (NCI) to evaluate their in vitro antiproliferative activity against a panel of 60 human tumor cell lines. AQ-12 exhibited significant antiproliferative activity against HCT-116 CRC and MCF-7 breast cancer cells at a single dose and further five doses. MTT assay was also performed for AQ-12 at different concentrations against these two cells, implying that AQ-12 exerted notable cytotoxicity toward HCT-116 (IC₅₀ = 5.11 ± 2.14 μM) and MCF-7 (IC₅₀ = 6.06 ± 3.09 μM) cells in comparison with cisplatin (IC₅₀ = 23.68 ± 6.81 μM and 19.67 ± 5.94 μM, respectively). This compound also augmented apoptosis in HCT-116 (62.30%) and MCF-7 (64.60%) cells comparable to cisplatin (67.30% and 78.80%, respectively). Molecular docking studies showed that AQ-12 bound to DNA, forming hydrogen bonding through the quinone scaffold. In silico pharmacokinetic determinants indicated that AQ-12 demonstrated drug-likeness with a remarkable pharmacokinetic profile for future mechanistic anti-CRC and anti-breast cancer activity studies.

Platinum-based systematic therapy in triple-negative breast cancer

Due to the lack of definitive hormone receptors, triple negative breast cancer (TNBC) patients receive little clinical benefit from endocrine or molecular targeted therapies, leading to a highly aggressive disease with a high recurrence rate and poor prognosis. In the past decades, chemotherapy has been the mainstay of treatment for TNBC, with taxane/anthracyclines as the representative regimen. However, increasing irreversible cardiotoxicity of anthracyclines and drug-resistance had to be noticed. Gradually, platinum-based chemotherapy has become a topic of interest for researchers. Based on the accumulating studies on platinum-containing regimens for TNBC patients, we will summarize the progress of relevant clinical trials focusing on platinum monotherapy (e.g., cisplatin, carboplatin and oxaliplatin) or in combination with other therapeutic modalities (e.g., other chemotherapeutic agents, molecular targeted therapies and immunotherapy). To further evaluate patient response to platinum and screen for the optimal population to benefit from platinum, we will also analyze current potential biomarkers, such as breast cancer susceptibility genes (BRCA1/2), homologous recombination repair deficiency (HRD), tumor infiltrating lymphocytes (TILs), TP53 family and other emerging indicators (e.g., intrinsic subtype, cyclin-dependent kinase 2 (CDK2) expression, vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9)).

Regulatory role of the transforming growth factor-β signaling pathway in the drug resistance of gastrointestinal cancers

Gastrointestinal (GI) cancer, including esophageal, gastric, and colorectal cancer, is one of the most prevalent types of malignant carcinoma and the leading cause of cancer-related deaths. Despite significant advances in therapeutic strategies for GI cancers in recent decades, drug resistance with various mechanisms remains the prevailing cause of therapy failure in GI cancers. Accumulating evidence has demonstrated that the transforming growth factor (TGF)-β signaling pathway has crucial, complex roles in many cellular functions related to drug resistance. This review summarizes current knowledge regarding the role of the TGF-β signaling pathway in the resistance of GI cancers to conventional chemotherapy, targeted therapy, immunotherapy, and traditional medicine. Various processes, including epithelial-mesenchymal transition, cancer stem cell development, tumor microenvironment alteration, and microRNA biogenesis, are proposed as the main mechanisms of TGF-β-mediated drug resistance in GI cancers. Several studies have already indicated the benefit of combining antitumor drugs with agents that suppress the TGF-β signaling pathway, but this approach needs to be verified in additional clinical studies. Moreover, the identification of potential biological markers that can be used to predict the response to TGF-β signaling pathway inhibitors during anticancer treatments will have important clinical implications in the future.

X-ray repair cross-complementing 1 polymorphism and prognosis of platinum-based chemotherapy in gastric and colorectal cancer: a meta-analysis

BACKGROUND AND AIM

The relationships between the X-ray repair cross-complementing 1 (XRCC1) Arg399Gln polymorphism (rs25487, G > A) and responses to platinum-based chemotherapy of gastric and colorectal cancer patients are controversial. Therefore, we performed a meta-analysis to assess the relationships.

METHODS

We retrieved the relevant articles from MEDLINE and EMBASE databases. Fourteen studies with 1618 gastric and colorectal cancer patients were included. Primary outcomes included response rate (RR), progression-free survival (PFS), and overall survival (OS). Odds ratio (OR) or hazard ratio with 95% confidence interval (CI) were estimated. All analyses were performed using the Stata software version 11.0 and Review Manager (v5.0).

RESULTS

In the dominant model, the A allele of XRCC1 Arg399Gln polymorphism was associated with reduced RR to platinum-based chemotherapy in all gastric and colorectal cancer patients (A/G + A/A vs G/G OR, 0.73; 95% CI, 0.55-0.96) and in Asians (OR, 0.62; 95% CI, 0.44-0.89) but not in Caucasians (OR, 0.92; 95% CI, 0.60-1.42). In addition, stratified analysis for different types of cancers indicated a marginally significant decrease of RR in colorectal cancer patients (OR, 0.68; 95% CI, 0.46-1.00) but not in gastric cancer patients (OR, 0.78; 95% CI, 0.53-1.15). However, we did not observe a significant association between XRCC1 Arg399Gln polymorphism and hazard for PFS and OS for gastric and colorectal cancer patients in all tested models.

CONCLUSIONS

XRCC1 Arg399Gln polymorphism may be a valuable genetic marker for platinum-based chemotherapy of gastric and colorectal cancer patients, and more well-designed studies with large samples are needed to confirm our findings.

Small bowel adenocarcinoma: understaged and undertreated?

BACKGROUND

Primary small bowel adenocarcinoma (SBA) is a rare, chemoresistant tumor with an aggressive clinical nature. Surgery is the mainstay of therapy, but the extent of lymph node (LN) recovery necessary for optimal care of jejunoileal SBA is unknown.

MATERIALS AND METHODS

The SEER database was queried to identify patients whose primary jejunoileal SBA was diagnosed between 1995 and 2005. Patients were grouped by AJCC stage and number of LNs recovered from the surgical specimen.

RESULTS

Of 1444 patients with primary SBA, 93 (6.4%), 529 (36.6%), 356 (24.7%), and 466 (32.3%) were initially diagnosed with stage I, II, III, and IV disease, respectively. Five-year overall survival (OS) rate was 59.8%, 39.5%, 27.0%, and 3.2% for patients with stage I, II, III, and IV SBA, respectively. When ≥10 nodes were recovered, OS rate increased nonsignificantly in stage I (73.2% vs. 55.6%) and significantly in stage II (61.8% vs. 32.9%, P < .001) but was unchanged in stage III (27.4% vs. 27.3%, P = .13). Recovery of ≥10 nodes occurred in 26.9%, 23.6%, and 42.1% of patients with stage I, II, and III SBA, respectively. Multivariate analysis identified age, AJCC stage, site of primary tumor, recovery of ≥10 LNs, and number of positive nodes as significant for OS.

CONCLUSIONS

We have found SBA staging is largely inadequate. Our results suggest recovery of ≥10 LNs ensures accurate staging. Improvement in stage II SBA OS after adequate LN may reflect a high degree of understaging in this dataset rather than a therapeutic effect of LAD.

Comparison of the combined action of oxaliplatin or cisplatin and radiation in cervical and lung cancer cells

BACKGROUND AND PURPOSE

To test the combined effects of oxaliplatin and radiation versus cisplatin and radiation using human cervical and lung cancer cell lines.

MATERIAL AND METHODS

CaSki cervical cancer cells, and A549 lung cancer cells were cultured under standard conditions. Cells were treated with escalating doses of gamma-irradiation (0-6 Gy), and with oxali- and cisplatin for 2 h or 24 h, or a combination of both. Cell survival was measured by a colony-forming assay. Survival curves were fitted to the data using the linear quadratic model. Sensitizer enhancement ratios (SER) were calculated at the 37% survival level, and isobologram analysis was applied to test for the drug-radiation interactions.

RESULTS

Oxaliplatin as well as cisplatin alone were cytotoxic in both cell lines. In CaSki cells, oxaliplatin and cisplatin significantly increased radiation toxicity. In A549 cells no increase of radiation toxicity was observed after treatment with cisplatin, however, isobologram analysis revealed supra-additive interaction between oxaliplatin and radiation in A549 cells.

CONCLUSION

Oxaliplatin had the same effectiveness on tumor cells as cisplatin and induced enhanced radiation toxicity in lung cancer cells, where cisplatin was not able to achieve radiosensitization.

In vitro and in vivo antitumour effects of novel, orally active bile acid-conjugated platinum complexes on rat hepatoma

(NH3)2Pt(triacid) and (PPh3)2Pt(dehydrocholate)2 are novel bile acid-conjugated platinum complexes administered by oral route. The aims of the present study were to evaluate their in vitro cytotoxic activities on rat hepatoma cell line N1-S1, the in vivo antitumour effects in a syngeneic and orthotopic rat hepatoma model and the drug-related toxicities. Cisplatin, carboplatin and mitoxantrone were used as control drugs. In vitro experiments showed a concentration- and time-dependent antiproliferative activity of bile-conjugated platinum complexes. (NH3)2Pt(triacid) had similar effects on cell growth of cisplatin and carboplatin (e.g. at 48 h, IC50 0.7+/-0.05 microM vs. 0.63+/-0.28 microM and 1.1+/-0.3 microM, respectively; mean+/-S.D.). (NH3)2Pt(triacid) was able to inhibit tumour growth in a dose-dependent extent, reaching the maximum inhibitory effect at the 80 mg/kg dose (1.95+/-0.5 g vs. 13.85+/-3.9 g of control tumour weight). By contrast, despite the promising in vitro antiproliferative activity, (PPh3)2Pt(dehydrocholate)2 showed no significant in vivo antitumour effect. The toxicity profile of (NH3)2Pt(triacid) resulted favourable with minimal loss of weight and no gastrointestinal or neurological symptoms. Instead, (PPh3)2Pt(dehydrocholate)2 showed dose-dependent signs of severe weight loss and neurological alterations. In conclusion (NH3)2Pt(triacid) is a tolerable and active platinum derivative endowed by a preclinical antitumour activity by oral route.

The emerging role of oxaliplatin in the treatment of gastric cancer

Gastric cancer is often diagnosed in locally advanced or metastatic stages and, therefore, of poor prognosis. Many controversies exist about surgery, neoadjuvant, adjuvant and palliative treatments of gastric cancer. So we need to explore a variety of novel management options including the use of new agents and new combinations. Some of these agents include oral fluoropyrimidine, irinotecan, docetaxel and oxaliplatin. Oxaliplatin is a diaminocyclohexane-platinum compound that is significantly different from cisplatin and carboplatin with respect to its activity and toxicity. Oxaliplatin is an alkylating agent inhibiting DNA replication by forming adducts between two adjacent guanines or guanine and adenine molecules. However, the adducts of oxaliplatin appear to be more effective than cisplatin adducts in regard to the inhibition of DNA synthesis. In contrast to cisplatin, oxaliplatin has demonstrated efficacy alone and in combination with 5-fluorouracil in advanced colorectal cancer. Many studies are ongoing to test the combination in noncolorectal gastrointestinal tumors and other malignancies. This review focuses on the increasing amount of data concerning the clinical activity of oxaliplatin-based regimens in advanced gastric cancer.